CA2210455A1 - Water-based adhesives containing thermally-inhibited starches - Google Patents

Abstract

Thermally-inhibited starches and flours are used in conventional water-based adhesives such as corrugating, cigarette, remoistenable, kraft adhesives. The starches or flours are thermally-inhibited by dehydrating the starch to anhydrous or substantially anhydrous and then heat-treating the starch or flour for a time and at a temperature sufficient to inhibit the starch and improve its viscosity stability. The starch or flour may be thermally or non-thermally dehydrated (e.g., by alcohol extraction or freeze-drying). Preferably, the pH of the starch is adjusted to at least a neutral pH prior to the dehydration.

Description

W096/23038 PCT~S96100988 WATER-BASED ADHESIVES CONTAINING
Y-INHIBITED STARCHES
Technical Field This invention relates to water-based adhesives contAin;ng starches and flours.
Bac~Lo~nd Art Heat Treatment of Starches and Flours Heat/moisture treatment and annealing of starches and/or flours are taught in the literature and distingll;che~ by the amount of water present.
~nneAling~ involves slurrying a grAnl~lAr starch with cess water at temperatures below the starch's or f lour's gelatinization temperature. "Heat/moisture-treatment" involves a semi-dry treatment at temperatures below the starch's or f lour's gelatinization temperature, with no added moisture and with the only moisture present being that normally present in a starch granule (which is typically 10% or more).
In the following discussion, a history of the various heat/moisture and Ann~Al;~g treatments of starch and/or flour is set out.
GB 263.897 (accepted Dec. 24, 1926) discloses an im~Lovement in the heat treatment process of GB
228,829. The process of the '829 patent involves dry heating flour or wheat to a point at which substantially all of the gluten is rendered non-retainable in a wA~h; ng test and then blending the treated flour or wheat with untreated f lour or wheat to provide a blend having superior strength. The im~ovement of the '897 patent is cont; nll; ng the dry heating, without, however, gelatinizing the starch, for a considerable time beyond that n~ceccAry to render all of the gluten non-CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 ret~;n~hle. "Dry-heating" excludes heating in a steam atmosphere or an atmosphere con~i n; ng considerable quantities of water vapor which would tend to gelatinize the starch. The wheat or flour may contain the usual amount of moisture, preferably not greater than 15%. The heat treatment may exceed 7 hours at 77-93~C (170-200~F), e.g., 8 to 14 hours at 82~C (180~F) or 6 hours at 100~C
(212~F).
GB 530.226 (accepted Dec. 6, 1940) discloses a method for drying a starch cake cont~i ni ng about 40-50%
water with hot air or another gas at 149~C (300~F) or above without gelatinizing the starch. The starch cake is disintegrated by milling it to a finely divided state prior to drying.
GB-595.552 (accepted December 9, 1947) discloses treatment of starch, more particularly a corn starch, which involves drying the starch to a relatively low moisture content of 1-2%, not ~Ycee~ing 3%, and subsequently dry heating the substantially moisture-free starch at 115-126-C for 1 to 3 hours. The treatment is inten~ to render the starch free from thermophilic bacteria. The starch should not be heated longer than n~C~c~ry to effect the desired sterilization.
U.S. 3 490.917 (issued January 20, 1970 to C.A.F. Doe et al.) discloses a process for preparing a non-chlorinated cake flour suitable for use in cakes and sronges having a high sugar to flour ratio. The starch or a flour in which the gluten is substantially or completely detached from the starch granules is heated to a temperature of from 100-140~C and then cooled. The conditions are selected so that dextrinization does not occur, e.g., about 15 minutes at 100-115~C and no hold and rapid cooling at the higher temperatures. The heat treatment should be carried out under conditions which allow the water vapor to escape. The reduction in CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 moisture content due to the heat treatment ~çpDn~ upon the temperature employed. At treatment temperatures of 100-105~C, the moisture content is r~ c~ from 10-12% to 8-9%, by weight, while at medium and high temperatures 5 the moisture content is typically reduced to 7% or less.
Preferably, during cooling the moisture is allowed to reach moisture equilibrium with the atmosphere. The gelatinization temperature of the heat treated starch or flour is a~roximately 0.5-1~C higher than that of a 10 comparable chlorinated flour or starch. The heating can be carried out in many ways, including heating in a hot air fluidized bed.
U.S. 3 578 497 (issued May 11, 1971 to E. T.
Hjermstad) discloses a process for non-chemically 15 improving the paste and gel properties of potato starch and imparting a swelling temperature as much as -7 to -1~C (20 to 30~F) higher. A conc~ntrated suspension (20-40% dry solids) at a neutral pH (5.5-8.0, preferably 6-7.5) is heated either for a long time at a relatively low 20 temperature or for a short time at sllcc~csively higher temperatures. The suspension is first heated at a temperature below the incipient swelling temperature of the particular batch of starch being treated (preferably 49~C - 120~F). Then the temperature is gradually raised 25 until a temperature well above the original swelling temperature is attained. It is essential that swelling be avoided during the different heating periods so that gelatini~Ation does not occur. After this steeping treatment the starch has a higher degree of gr~n~ r 30 stability. It resists rapid gelatinization and pro~llcec a rising or fairly flat viscosity curve on cooling. The r pastes are very short textured, non-gumming, non-slimy, cloudy and non-cohesive. They form firm gels on cooling and aging.

CA 022104~ 1997-07-24 W096/23038 PCT~S96100988 U.S. 3 977 897 (issued August 31, 1976 to Wurzburg et al.) discloses a method for preparing non-chemically inhibited amylose-contA;n;ng starches. Both cereal and root ~tarches can be inhibited, but the inhibition effects are more observable with root starches. Amylose-free starches, such as waxy corn starch, show no or very slight inhibition. The Brabender viscosity of cooke~ pastes derived from the treated starch was used to determine the inhibition level.
Inhibition was indicated by a delayed peak time in the case of the treated corn starch, by the lack of a peak and a higher final viscosity in the case of the treated achira starch, and by the loss of cohesiveness in the case of the treated tapioca starch. The grA~l7lAr starch is susr~n~e~ in water in the presence of salts which raise the starch's gelatinization temperature so that ~he suspension may be heated to high temperatures without causing the starch granules to swell and Lu~LuLe yielding a gelatinized product. The preferred salts are sodium, ammonium, magnesium or potassium sulfate; sodium, potassium or ammonium chloride; and sodium, potassium or ammonium phosphate. About 10-60 parts of salt are used per 100 parts by weight of starch. Preferably, about 110 to 220 parts of water are used per 100 parts by weight of starch. The suspension is heated at 50-100~C, preferably 60-90~C, for about 0.5 to 30 hours. The pH of the suspension is maint~;ne~ at about 3-9, preferably 4-7.
Highly A 1 kA 1 i ne systems, i.e., pH levels above 9 retard inhibition.
U.S. 4 013 799 (issued March 22, 1977, to Smalligan et al.) discloses heating a tapioca starch above its gelatinization temperature with insufficient moisture (15 to 35% by total weight) to produce gelatinization. The starch is heated to 70-130~C for 1 CA 022104~ 1997-07-24 W096l23038 PCT~S96/00988 to 72 hours. The starch is used as a thickener in wet, pre-csok~ baby foods having a pH below about 4.5.

U.S. 4.303 451 (issued December 1, 1981 to Seidel et al.) di~closes a method for preparing a pregelatinized waxy maize starch having improved flavor characteristics reminiscent of a tapioca starch. The starch is heat treated at 120-200~C for 15 to 20 minutes.
The pregelatinized starch has gel strength and viscosity characteristics suitable for use in pudding mixes.
U.S. 4 303 452 (issued Dec. 1, 1981 to Ohira et al.) discloses smoking a waxy maize starch to im~lo~e gel strength and impart a smoky taste. In order to counteract the smoke's acidity and to obtain a final product with a pH of 4-7, the pH of the starch is raised to pH 9-11 before smoking. The preferred water content of the starch during smoking is 10-20%
The article "Differential ScAnn;~g Calorimetry of Heat-Moisture Treated Wheat and Potato Starches" by J.W. Donovan et al. in Cereal Chemistry, Vol. 60, No. 5, pp. 381-387 ~1983) discloses that the gelatinization temperature of the starches increased as a result of the heat/moisture treatment or ann~Al;~g. See also the article "A DSC Study Of The Effect Ann~Aling On Gelatinization Behavior of Corn Starch" by B.R. Krueger et al. in Journal of Food Science, Vol. 52, No. 3, pp.
715-718 (1987).
U-S- 4.391.836 (;~Cll~ July 5, 1983 to C.-W.
Chiu) discloses instant gelling tapioca and potato starches which are non-grAnlllAr and which have a reduced viscosity. Unmodified potato and tapioca starches do not normally gel. The starches of the patent are rendered non-grAnnl~ and cold-water-dispersible by forming an aqueous slurry of the native starch at a pH of about 5-12 and then drum-drying the slurry. The starches are CA 022104~ 1997-07-24 -W096/~038 PCT~S96/00988 rendered gelling by heat treating the drum-dried starch for about 1.5 to 24 hours at 125-180~C to reduce the viscosity to within defined Brabender viscosity limitations.
U.S. 4 491 483 (issued January 1, 1985 to W.E.
Dudacek et al.) discloses subjecting a semi-moist blend of a granular starch with at least 0.25 wt. % of a fatty acid surfactant and sufficient water (about 10-40 wt. %) to a heat-moisture treatment at from about 50-120~C, followed by drying to about 5-15 wt. %, preferably 10 wt.
%, moisture. The heat-moisture treated starch-surfactant ~oduct is characterized by a hot water dispersibility of from about 60-100% and a higher pasting temperature than the grA~tllAr starch from which it is derived.
Preferably, the treatment takes place in a closed contA; n~r SO that the moisture can be maint~i ne~ at a constant level. The preferred conditions are 3 to 16 hours at 60-90~C. Degradation and dextrinization reactions are undesirable as they destroy the thic~ g ability of the starch. The use of conditions, such as, e.g., 35% moisture at 90~C for 16 hours results in r~ c~ paste viscosity. It is believed the ~ once of the surfactant during the treatment permits formation of a complex within the partially swollen starch matrix with straight chain portions of the starch molecules. The limited moisture environment allows complex formation without gelatinization.
Japanese Patent Publication No. 61-254602, (published December 11, 1987) discloses a wet and dry method for heating waxy corn starch and derivatives thereof to impart emulsification properties. The wet or dry starch is heated at 100-200~C, preferably 130-150~C, for 0.5 to 6 hours. In the dry method, the water content is 10%, preferably 5%, or less. In the wet method, the CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 water content is 5 to 50%, preferably 20-30%. The pH is 3.5-8, preferably 4-5.
The article "Hydrothermal Modification of Starches: The Difference between Annealing and Heat/Moisture-Treatment", by Rolf Stute, Starch/Starke Vol. 44, No. 6, pp. 205-214 (1992) Lepol~s almost identical modifications in the properties of potato starch with ~nn~Aling and heat/moisture treatments even through the alteration of the granular structure is different. The Br~h~A~r curves of the heat/moisture-treated and AnneAled potato starches show the same typical changes, including a higher gelatinization temperature and a lower peak viscosity or no peak. The DSC curves also show a shift to higher gelatinization temperatures for both treatments. A combined treatment involving ~nne~ling a heat/moisture-treated potato starch leads to a further increase in gelatinization temperature without detectable changes in gelatinization enthAlAry and with retention of the viscosity changes caused by the heat treatment. A combined treatment involving annealing a heat/moi~ L~L e treat potato starch does not lower the gelatinization temperature, when compared ts the base starch, and increases the gelatinization temperature at higher heat/moisture treatment levels.
Chemical Crosslinkinq of Starches and Flours Starches and flours are chemically modified with difunctional reagents such as phosphorus oxychloride, sodium trimet~phosphate, adipic anhydride, acetic anhydride and epichlorohydrin to produce chemically crosslinked starches having excellent tolerance to processing variables such as heat, shear, and pH extremes. Such chemically crosslinked starches (also referred to as "inhibited starches") provide a desirable smooth texture and possess viscosity stability throughout processing operations and normal shelf life.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/OOs88 In contrast, when unmodified (i.e., non-crosslinked) starches, particularly waxy-based starches, are gelatinized, they reach a peak viscosity which soon begins to breakdown, loose thick~n;ng capacity and textural qualities, and behave unpredictably during storage as a result of the stresses encountered during processing. Heat, shear, and/or an extreme pH, especially an acidic pH, tend to fully disrupt the starch granules and disperse the starch.
ADHESIVES
Starches have long been used as an adhesive material in various applications such as the fabrication of corrugated board, paper bags, paper boxes, laminated paperboard, spiral-wound tubes, gummed labels, gummed tapes and other gumming applications. See the discussion in Starch Chemistry and Technology, 2nd Edition, by R.
Whistler et al., 1984, pp. 593-610 and Chapter 22 "Starch and Its Nodifications" by M.W. Rutenberg, pp. 22-63 and 22-64 in "~n~hook of Water-Soluble Gums and Resins"
edited by Robert L. Davidson and published by McGraw-Hill Book Co. (1980).
U.S. 2 791.512 (issued 5/7/57 to Hutch et al.) discloses remoisten;~g adhesive compositions which are an intimate mixture of water and dextrinized amylopectin which is substantially free of amylose (e.g., waxy maize). At about 40-60% solids, the viscosity is 2,000-20,000 cps at about 52-54~C (125-130~F). Up to 30~ of ordinary converted corn starch or corn dextrine can be included in the adhesive composition.
U.S. 3 155 527 (issued 11/3/64 to Mentzer) discloses a water-resistant adhesive suitable for paper board production contains about 1 part of gelatinized starch, about 3-6 parts of ungelatinized starch, about 0.5-2 parts of urea, about 0.25-1 part of formaldehyde, about 15-25 parts of water, and an alkaline material CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 present in an amount sufficient to give a pH of about 10-12.5. The carrier portion is formed by gelatinizing starch in an alkaline medium, cooling the resulting paste, and mixing with a slurry of ungelatinized starch, water, urea, and formaldehyde. Suitable starches include those normally present in water-resi~tant adhesives, e.g., corn, potato, waxy maize, sorghum, and/or tapioca.
Y.S. 3 331 697 (issued 7/18/67 to Salamon) discloses an adhesive adapted for ho~Ai~g gypsum and other cellulosic materials which is an aqueous paste cont~;ning about 3-15 wt. % of an alkylene oxide-modified starch (e.g., potato starch reacted with 1-7% ethylene oxide), about 2-20 wt. % of a fibrous reinforcing filler (e.g., asbestos), about 30-65 wt. % of a particulate filler (e.g., finely divided limestone, and water in an amount sufficient to give a solid content of 45-75 wt. %.
U.S. 3 408 214 (issued 10/29/68 to Mentzer) discloses a remoisten;~g adhesive which has improved open time and bond time. The adhesive mixture contains an ungelatinized chemically modified starch substantially free of set back propylene or polyethylene glycol (200-7,000 mol. wt.), water, and optionally a plasticizer.
The components are mixed in sufficient water to give a slurry of 30-70% solids, preferably the pH is adjusted to 8-12, and the mixture is heated to gelatinize the starch.
U.S. 3 477 903 (issued 11/11/69 to T.S.
Semegran et al.) discloses water resistant adhesive compositions which comprise a mixture, in an aqueous medium, of amylose product cont~;n;ng at least 55 wt. %
amylose and a peptizing agent selected from the group consisting of alkali metal hydroxides, alkali or alkaline earth metal salts, salts of transition metals, sodium salicylate, and formaldehyde. The amylose product may be an isolated amylose as the whole starch. The amylose may be heat and/or acid treated or oxidized to give thin CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 boiling starches. The amylose may al~o be chemically derivatized.
U.S. 3 640 756 (issued 2/8/72 to Beersma et al.) discloses a remoistenable pregummed paper such as wall paper which are coated with a layer of a high mol~cl~lAr weight polymeric binding agent on which is absorbed a cold-water-swelling, chemically crosslinked granular starch ether or ester cont~i n; ng hydLophilic ~ubstituents (e.g., a crosslinked grAnlll~r starch phosphate prepared by reaction with a phosphorus-con~; n; ng acid and urea or a crosslinked granualr carboxymethyl starch crosslinked with epichlorohyddrin.
The degree of crosslinking should be 1-50 crosslinks per anhyd~oylucose unit. All starch bases are suitable.
Y.S. 3 690.938 (issued September 12, 1972 to T.G. Swift) discloses a remoistenable adhesive composition with excellent "slip" properties for preparted wall coverings. The adhesive is a blend of 30-40 wt. % of an acid-hydrolyzed waxy starch (at least 80%
amylopectin), 15-25 wt. % of a slip agent such as methyl, hydlo~e~hyl, and carboxymethyl cellulose, and 35-55 wt.
% (dry ~olids) of a plasticizer such as sodium or potassium methacrylate.
U.S. 3.810 783 (issued 5/14/7~ to W.A. Bomball) discloses a starch-hA-c~ remoistenable prepasted wallcovering adhesive which comprises an oxidized yellow dent corn starch, methyl ether of cellulose, predispersed coating clay, hydrolyzed polyvinyl alcohol, monobasic sodium phosphate, paraffin wax, a sodium salt of sulfonated paraffin wax, a crossl; nk; ng agent such as glyoxal, small amounts of a suitable fungicide, and optionally polyvinyl acetate. The oxidation is ~G~l~Lolled to give a starch with a Brookfield viscosity of 1,200-2,000 cps (30% solids, 155~F, 20 rpm, No. 3 spindle).

CA 022104~ 1997-07-24 W096/23038 P~ 100988 U.S. 3,844,807 (issued 10/29/74 to G.F. Bramel) discloses water resistant, short tack adhesive paste for ho~; ng paper products such as multi-wall envelope bags.
the dry pre-blend comprises two premix blends of acid hydrolyzed starch, hydroxyethylated starch, buffering salts and a specific type of starch modifier (e.g., polyoxyethylene laurate). The preblends and mixture thereof are slurried with water and a urea-formaldehyde resin (added for water resistance prior to use. The mixture is then cooked.
U.S. 3,950,593 (issued 4/13/76 to W.A. Bomball et al.) discloses adhesive formulations for pre~mmed remoistenable tape having a long open ime and short tack time. An acid hydrolyzed derivatized waxy maize starch is used as a replacement for animal glue. In one emho~;ment, the major ingredient is a waxy maize starch which is first acid hydrolyzed and then copolymerized with an acrylamide monomer. In a second embodiment, an acid-hydrolyzed, cyanoethylated waxy maize starch provides the major adhesive ingredient.
U.S. 4,329,181 (issued May 11, 1982 to Chiu et al.) discloses a corrugating adhesive having im~o~ed tack where the gelatinized carrier starch is an amylose starch contAining at least 40% amylose and an AlkAli-labile stabilizing groups (e.g., acetyl) which areremoved when the carrier starch is in~ol~oLated into an alkaline corrugating adhesive.
U.S. 4,366,275 (issued 12/28/82 to M.A. Silano et al.) discloses a water-resistant starch-hA~e~ alkaline corrugating adhesive composition which contains a crosslinking additive which is low in free formaldehyde.
U.S. 5,085,228 (issued 2/4/92 to N.T. Mooney et al.) discloses a starch-based adhesive for cigarette manufacturing which comprises a mixture of a chemically crossl inke~ starch, a fluidity or converted starch. ~he CA 022104~ 1997-07-24 W096l23038 PCT~S96/00988 starches have an amylopectin content of at least 70 wt. %
and are prepared by cook;~g at high temperature and pressure. Suitable starches include waxy maize, waxy rice, tapioca, potato, maize (corn), wheat, arrowroot and sago.
U.S. 5 087,649 (issued 2/11/92 to J. Wegner et al.) discloses a dry paste, such as a wallpaper paste, which is prepared from a mixture contAi~;ng carboxymethylated and/or alkoxylated starch, a cellulose ether, a water dispersible or water soluble polymer, other conventional additives (preservatives, wetting agents, and fillers), and water. The adhesive is dried in a thin layer on surface by heating to 80-200~C. The starch can be optionally treated with a chemical crossl i nk i ng agent.
Y.S. S 155 140 (;cc~ 10/13/92 to K. Marten et al.) discloses a cigarette gluing adhesive which is an aqueous mixture contA; n; ng gum arabic, a water soluble starch degradation product (oxidatively or hydrolytically degraded starches and dextrins) and/or carboxymethyl starch and/or gelatinized starch an optionally typical preservatives.
U.S. 5 329 004 (issued 7/12/94 to J.L. Eden et al.) discloses a cigarette manufacturing adhesive which 2S is a natural based liquid starch phosphate. The starch phosphate is made from a fluidity or converted starch having a high amylopectin content. The final starch p~o phAte composition is steam injection cooked at high temperature and pressure.
There is a need in the adhesives industry for non-chemically-crosslinked starches which have the same functional properties as chemically-crossl; nk~ starches.
Disclosure of Invention The present invention provides aqueous-based adhesives which comprise an aqueous-based carrier and a CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 cooked or precooked (i.e., pregelatinized) thermally-inhibited starch or flour. The thermally-inhibited starch or flour may be a granular starch or a pregelatinized granular or non-granular starch. The pregelat; n; ~Ation may be carried out prior to or after the thermal inhibition. For some uses modified thermally-inhibited starches or flours may be useful.
The starches and flours are thermally inhibited, without the addition of chemical reagents, in a heat treatment process that results in the starch or flour becoming and rem~;n;~g inhibited. The starches and flours are referred to as "inhibited" or "thermally-inhibited (abbreviated "T-I"). When these thermally-inhibited starches and flours are dispersed and/or cooked in water, they exhibit the textural and viscosity properties characteristic of a chemically-crosslinked starch. The starch granules are more resistant to viscosity breakdown. This resistance to breakdown results in what is subjectively considered a non-cohesive or "short" texLu~ed paste, meAn;ng that the gelatinized starch or flour tends to be salve-like and heavy in viscosity rather than runny or gummy.
When the thermally-inhibited starches and flours are non-pregelatinized grAn~llAr starches or flours, the starches or flours exhibit an lln~hA~ged or rPAl~ceA gelatinization temperature. In collLlast, most An~eAled and heat/moisture treated starches show an increased gelat;~;zAtion temperature. Chemically-crossl;nkeA starches show an unchanged gelatinization temperature. It is believed the overall granular structure of the thermally-inhibited starches and flours has been altered.
The starches and flours that are substantially completely inhibited will resist gelatinization. The starches and flours that are highly inhibited will CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 gelatinize to a limited extent and show a continuing rise in vi~cosity but will not attain a peak viscosity. The starches and flours that are moderately inhibited will exhibit a lower peak viscosity and a lower percentage breakdown in viscosity compared to the same starch that is not inhibited. The starches and flours that are lightly inhibited will show a slight increase in peak viscosity and a lower percentage breakdown in viscosity compared to the same starch that is not inhibited.
The starches and flours are inhibited by a process which comprises the steps of dehydrating the starch or flour until it is anhydrous or substantially anhyd~ous and then heat treating the anhydrous or substantially anhydrous starch or flour at a temperature and for a period of time sufficient to inhibit the starch or flour. As used herein, "substantially anhydrous"
means contA; n i ng less than 1% moisture by weight. The dehydration may be a thermal dehydration or a non-thermal dehydration such alcohol extraction or freeze drying. An optional, but preferred, step is adjusting the pH of the starch or flour to neutral or greater prior to the dehydration step.
The amount of thermal inhibition required will ~pen~ on the reason the starch or flour is included in the adhesive, as well as the particular processing conditions used to prepare the adhesive. A~hPcives prepared with the thermally-inhibited starches and flours will pQcc~cc viscosity stability, process tolerance such as resistance to heat, acid, and shear, and improved te~L~e. Aqueous dispersions or cooks of the thermally-inhibited starches exhibit enh~nceA viscosity stability and, in some cases, increased adhesion which makes them particularly useful in adhesives.
ner~; ng on the extent of the heat treatment, various levels of inhibition can be achieved. For CA 022104~ 1997-07-24 .

W096/23038 PCT~S96/00988 example, lightly inhibited, higher viscosity products with little breakdown, as well as highly inhibited, low viscosity products with no breakdown, can be prepared by the thermal inhibition process described herein.
Typically, if a highly inhibited starch or flour is used, the amount of the starch or flour is about 1-20%, preferably 2-5%, by weight hAs~ on the weight of the adhesive composition. Typically, if a lightly inhibited starch or flour is used, the amount of the starch or flour is about 1-40%, preferably 10-20%, by weight based on the weight of the adhesive composition.
The adhesives can be a liquid adhesive or a paste prepared by cooking the starch or flour in an aqueous medium or a dried film of a remoistenable adhesive. Adhesives contAining the thermally-inhibited starches or flours are especially useful for kraft adhesives, cigarette-making adhesives, envelope adhesives, corrugating adhesives, lay-flat laminating adhesives, tube-win~ing adhesives, bottle labeling adhesives, other packaging and converting adhesives, and in the preparation of ceramic tile cement.
Mode(s) For Carrying Out The Invention All starches and flours are suitable for use herein. The thermally-inhibited starches and flours can be derived from any native source. A native starch or flour is one as it is found in nature in unmodified form.
Typical sources for the starches and flours are cereals, tubers, roots, legumes and fruits. The native source can be corn, pea, potato, sweet potato, hAnAn~ barley, wheat, rice, sago, amaranth, tapioca, so~yhum, waxy maize, waxy tapioca, waxy rice, waxy barley, waxy potato, waxy so~yhum, starches contAining greater than 40%
amylose, and the like.
The thermal inhibition process may be carried out prior to or after other starch or flour reactions CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 used to modify starch or flour. The starches may be modified by conversion (i.e., acid-, enzyme-, and/or heat-conversion), oxidation, phosphorylation, etherification (e.g., by reaction with ~ylene oxide), esterification (e.g., by reaction with acetic anhydride or octenylsuccinic anhydride), and/or chemical crossl ;nk;ng (e.g., by reaction with phosphorus oxychloride or sodium trimetaphosphate). The flours may be modified by bleaching or enzyme cGll~e~ion.
~-v~eduLes for modifying starches are described in the Chapter "Starch and Its Modification" by M.W. Rute~h~rg, pages 22-26 to 22-47, ~An~hook of Water Soluble Gums and Resins, R.L. Davidson, Editor (McGraw-Hill, Inc., New York, NY 1980).
Native grA~llAr starches have a natural pH of about 5.0 to 6.5. When such starches are heated to temperatures above about 125~C in the presence of water acid hydrolysis (i.e., degradation) of the starch occurs.
This degradation impedes or prevents inhibition.
Therefore, the dehydration conditions need to be cho~en 80 that degradation is avoided. Suitable conditions are thermally dehydrating at low temperatures and the starch's natural pH or thermally dehydrating at higher temperatures after increasing the pH of the starch to neutral or above. As used herein, "neutral" covers the range of pH values around pH 7 and is meant to include from about pH 6.5-7.5. A pH of at leat 7 is preferred.
More preferably, the pH is 7.5-10.5. The most preferred pH range is above 8 to below lO. At a pH above 12, gelat;n;~Ation more easily occurs. Therefore, pH
adjustments below 12 are more effective. It cho~ be noted that the textural and viscosity benefits of the thermal inhibition process tend to be ~nh~nce~ as the pH
is increased, although higher pHs tend to increase CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 browning of the starch or flour during the heat treating step.
To adjust the pH, the non-pregelatinized granular starch or flour is typically slurried in water or another aqueous medium, in a ratio of 1.5 to 2.0 parts of water to 1.0 part of starch or flour, and the pH is raised by the addition of any suitable base. Buffers, such as sodium phosphate, may be used to maintain the pH
if n~e~. Alternatively, a solution of a base may be sprayed onto the powdered starch or flour until the starch or flour attains the desired pH, or an alkaline gas such as ammonia can be infused into the starch or flour. After the pH adjustment, the slurry is then either dewatered and dried, or dried directly, typically to a 2-15~ moisture content. These drying pro~ed~Les are to be disting~ h~ from the thermal inhibition process steps in which the starch or flour is dehydrated to anhydrous or substantially anhydrous and then heat treated.
The starches or flours can be pregelatinized prior to or after the thermal inhibition process using methods known in the art. The amount of pregelat;ni~Ation, and consequently, whether the starch will display a high or a low initial viscosity when dispersed in water, can be regulated by the pregelatinization procedure used, as is known in the art.
The resulting pregelatinized starches are useful in applications where cold-water-soluble or cold-water-~rp~rSible starches are used.
Pregelatinized grAmllAr starches and flours have retAin~ their grAnlllAr structure but lost their polarization crosses. They are pregelatinized in such a way that a majority of the starch granules are swollen, but remain intact. Exemplary proceCces for preparing pregelatinized grAnlllAr starches are disclosed in U.S.

~ t CA 022104~ 1997-07-24 o\ ~ l -Y ~ J I~; +~'J ~ 344t;j6: # ~3 18 R~P~AC3MENT PA~E
4,~80,~51 ~i3sued Ju~y 28, 1981 to E. Pitchon et al.~, .S. ~,465,70~ ued ~ugust 1~, 19~ to J.~. ~astman et al.~, Y.~. 5.~37,9~ sued Augu~t 6, 1~1 to S.
Rajagopalan~, ~nd U.~. 5, 149f 7g9 (i~ued Septe~ber a2, l9g2 to Roger W. Ruben~).
Pre~elatinized non-granular starches and flour ha~e al30 10R; their polariza~io~ ~ra~ses ~nd h~ve ~ecome so ~wollen thit the ~tarches have lost their gra~ular ~3tructure an~ ~roken into fragment~. They can be prepared acc~ in~ t~' any of ~he known phy~ical, chemical ~r thermal pre~ela'cinization proc~3~e~ that de~tro~ the ~ anule ~uch ~ drum d~ying, extrusion, or jet-cooking.
See U.8. 1,51i.512 (i~ued ~ov. ~5, lg24 to R.~
Stut~ke), U.S. 1,901,109, ~issu~d March 14, 1~33 to W.
Maier); ~. 2,31~,453 ~ ued March 23, 1943 to A,A, S~lzbu~g; US. 2~5a2~198 (issued Ja~uary 8, 1957 to Q.R.
Ethr~dge~; US. 2, aos ,965 ~is~ued Septem~er lO, 1957 to O.R. ~h~idge~; US. 2,91g,214 (issued De~r~h_r 2~, 195 to O.R. ~thrilge); ~ ,~40, R7~ ued June ~4, 1~0 to ~.~. El~a~l; U.S. 3,086,8g~ ued Ap~il 23, 1963 to A. !Carko et al.); ~.3- 3,~3,836 ~ ued May lg, 1~4 to U.~. Win~rey); U.S. 3.137,5~2 (i~ued Ju~e 1~, 19~4 to T.F. Pra~zman et al.); ~.$. 3.234.04~ ued February 8, 1~66 to G.R. 3tchison); U.~. 3,~Q7,3~4 ~is ued ~eptember ~, 1971 to F.J. Ger~ino); .U.~ 3.,63Ø77~ ued December l~, Lg71 to A.A. Winkler); and ~.~. 5 131,953 i~sued ~ly ~ 9~ ~o J.J. Ka~ica et al.~. ;
I~ :he pre~elatiniza~ion proce~ erformed flr~t and the pregelatinized starch or flour i gr~nular, the pH i~ ~djl~ed ~y ~lu~rying ~he pregelatinized ~a~ular ~ar~h or ~lour in water in ~ r~tio of 1.5-2.0 p~rt~ to 1.0 ?~rt st~rch, and option~lly, ~he pH i~ j ~A~072~21~04~i~i 1997-07-24 AMENDEOSHER

W096/23038 PCT~S96/00988 adjusted to neutral or greater. In another embodiment, the slurry is simultaneously pregelatinized and dried and the dried, starch or flour is thermally inhibited. If the thermal inhibition process is performed first, the starch or flour is slurried in water, the pH of the starch or flour is adjusted to neutral or greater, and the starch or flour is dried to about 2-15% moisture.
The dried starch or flour is then dehydrated and heat treated. The inhibited starch or flour is reslurried in water, optionally pH adjusted, and simultaneously pregelatinized and dried.
For non-granular pregelatinized starches or flours prepared by drum drying, the pH is raised by slurrying the starch or flour in water at 30-40% solids and A~ ing a sufficient amount of a solution of a base until the desired pH is reached.
For non-granular pregelatinized starches or flours prepared by the continuous coupled jet-cooking/spray-drying process of U.S. 5.131.953 or the dual atomization/spray-drying process of U.S. 4.280.851, the starch or flour is slurred at 6-10% solids in water and the pH is adjusted to the desired pH by adding a sufficient amount of a solution of a base until the desired pH is reached.
Suitable bases for use in the pH adjustment step include, but are not limited to, sodium hyd~oxide, sodium carbonate, tetrasodium pyrophosphate, ammonium or~hsrho~phate, disodium orthophosphate, trisodium r~rh~te, calcium carbonate, calcium hydroxide, potassium carbonate, and potassium hydroxide, and any other bases a~ ~ved for use under applicable regulatory - laws. The preferred base is sodium carbonate. It may be possible to use bases not a~ved under the above regulations provided they can be washed from the starch CA 022104~ 1997-07-24 W096l23038 PCT~S96100988 so that the final product conforms to good manufacturing practices for the desired end use.
A thermal dehydration is carried out by heating the starch or flour heating device for a time and at a temperature sufficient to reduce the moi~ture content to less than 1%, preferably 0%. Preferably, the temperatures u~ed are 125~C or less, more preferably 100~
to 120~C. The dehydrating temperature can be lower than 100~C, but a temperature of at least 100~C will be more efficient for removing moisture.
Representative processes for carrying out the non-thermal dehydration include freeze drying or extracting the water from the starch or flour using a solvent, preferably a hydrophilic solvent, more preferably a hydrophilic solvent which forms an azeotropic mixture with water (e.g., ethanol).
For a laboratory scale dehydration with a solvent, the starch or flour (about 4-5% moisture) is placed in a Soxhlet thimble which is then placed in the Soxhlet apparatus. A suitable solvent is placed in the apparatus, heated to the reflux temperature, and refluxed for a time sufficient to dehydrate the starch or flour.
Since during the refluxing the solvent is c~nA~n~A onto the starch or flour, the starch or flour is ~YpQs~A to a lower temperature than the solvent's boiling point. For example, during ethanol extraction the temperature of the starch is only about 40-50~C even though ethanol's boiling point is above 78~C. When ethanol is used as the solvent, the refluxing is con~inlleA for about 17 hours.
The extracted starch or flour is removed from the thimble, spread out on a tray, and the ~Yc~cc solvent is allowed to flash off. The time required for ethanol to flash off is about 20-30 minutes. The dehydrated starch or flour is immediately placed in a suitable heating apparatus for the heat treatment. For a commercial scale CA 022104~ 1997-07-24 W096/23038 PCT~S9~9 dehydration any continuous extraction apparatus is suitable.
For dehydration by freeze drying, the starch or flour (4-5% moisture) is placed on a tray and put into a freeze dryer. A suitable bulk tray freeze dryer is available from FTS Systems of Stone Ridge, New York under the trademark Dura-Tap. The freeze dryer is run through a ~Lo~-ammed cycle to remove the moisture. The temperature is held constant at about 20~C and a vacuum is drawn to about 50 milliTorr (mT). The starch or flour is removed from the freeze dryer and immediately placed into a suitable heating apparatus for the heat treatment.
After it is dehydrated, the starch or flour is heat treated for a time and at a temperature sufficient to inhibit the starch or flour. The preferred heating temperatures are greater than about 100~C. For practical purposes, the upper limit of the heat treating temperature is about 200~C. Typical temperatures are 120-180~C, preferably 140-160~C, most preferably 160~C.
The temperature selected will depend upon the amount of inhibition desired and the rate at which it is to be achieved.
The time at the final heating temperature will ~p~n~ upon the level of inhibition desired. When a conventional oven is used, the time ranges from 1 to 20 hours, typically 2-5 hours, usually 3.5 - 4.5 hours.
When a fluidized bed is used, the times range from 0 minutes to 20 hours, typically 0.5-3.0 hours. Longer times are required at lower temperatures to obtain more inhibited starches. Different levels of inhibition may be required ~p~n~ing on the adhesive end use - application, e.g., to adjust the final viscosity/solids ratio and/or to achieve specific rheological ~ ~erLies.
For most applications, the thermal dehydrating and heat treating steps will be continuous and CA 022104~ 1997-07-24 Wos6/23o38 PCT~S96/00988 accompli~heA by the application of heat to the starch or flour beginning from ambient temperature. The moisture will be driven off during the heating and the starch or flour will become anhydrous or substantially anhydrous.
Usually, at the initial levels of inhibition, the peak viscosities are higher than the peak viscosities of starches or flours heated for longer times, although there will be greater breakdown in viscosity from the peak viscosity. With continued heat treating, the peak viscosities are lower, but the viscosity breakdowns are less.
The process may be carried out as part of a continuous process involving the extraction of the starch from a plant material.
As will be seen in the following examples, the source of the starch or flour, initial pH, dehydrating conditions, heating time and temperature, and equipment used are all interrelated variables that affect the amount of inhibition.
The heating steps may be performed at normal res, under vacuum or under pressure, and may be accompl i.Ch~A by conventional means known in the art. The preferred method is by the application of dry heat in dry air or in an inert gaseous environment.
The heat treating step can be carried out in the same apparatus in which the thermal dehydration occurs. Most conveniently, the process is continuous with the thermal dehydration and heat treating o~u~ling in the same apparatus, as when a fluidized bed reactor is used.
The dehydrating and heat treating apparatus can be any industrial ovens, conventional ovens, microwave ovens, dextrinizers, dryers, mixers and blenders equipped with heating devices and other types of heaters, provided that the apparatus is fitted with a vent to the CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 atmosphere so that moisture does not accumulate and precipitate onto the starch or flour. The preferred apparatus is a fluidized bed. Preferably, the apparatus is equipped with a means for removing water vapor, such as, a vacuum or a blower to sweep air or the fluidizing gas from the head-space of the fluidized bed. Suitable fluidizing gases are air and nitrogen. For safety reA~QnC~ it is preferable to use a gas contAin;ng less than 12% oxygen.
Superior inhibited starches and flours having high viscosities with low percentage breakdown in viscosity are obtA;~e~ in shorter times in the fluidized bed reactor than can be achieved using other conventional heating ovens or dryers.
The starches may be inhibited individually or more than one may be inhibited at the same time. The starches may be inhibited in the pr~C~nc~ of other materials or ingredients that would not interfere with the thermal inhibition process or alter the ~opelLies of the starch product.
Following the thermal inhibition step, the resulting starches may be screened to the desired particle size. If the starch is a non-pregelatinized grAntllAr starch, the starch can be slurried in water, w~ A, filtered, dried, and bleached. If the starch is a grAnlllAr pregelatinized starch, the starch can be wAche~ by any known methods that will maintain grAmllAr integrity.
If desired, the pH may be adjusted.
Industrial ApPlicability The thermally-inhibited starches and flours can - be used wherever starches and flours are conventionally used in adhesives. Typical adhesive categories include - liquid adhesives, pastes, cold-water-soluble adhesives, water-resistant adhesives, and numerous other CA 022104~ 1997-07-24 , 24 REPI.Ar~M3NT PA~
appli~ation~. In most ~ppli~ation~, ~he ~t~r~h is cooked and 801u~iliz d an~ used ~ either the only colnp~nen~ in ~ddition to w~ter i~ the adhesive or a~ an added comporlent in nore complex ~ormula~ ion~ to pro~ride the re~a~lr~d tack, overall adh~ion, ~olution vi3cosity, s~ability, ani/or de~ired rheologica~ ch~acteristlcs.
Adh~si~e3 for ~pecific application~ include corrugating aihesi~res, mu~iwall bag adhesi~res, lami~ating adhesives, tube-winding adhe~lves, labelling adhesive~ e bag searn a~hesi~reg, tissue arld towel adhesive~, ci~arette adhesive~, w~llpaper adhe~i~es, adhesive~ ~or disposables, remoistenable adhe~i~e~, bcokb~ in~ a~he~ive3, cup and plate adhesi~re~, ca~e and c~rtcn s~al a-7he~ivee, car'c~n f~x~ning adhe~i~e~, glued lap adhe~i~e~, and the like.
Mo~ cig~re~e-making adhe3i~re3 are based on ~ynthetic polym~r ~y~temg. ~here is, ho~e~e~, a growing trend to th~ u6e of natural products in thi~ area.
Modified ~ta~ches, such as chemically modified ~tarc~hes and dextrin~, ar~ being u8~d for ~uch con~tructions.
Adhe~ive~ ccntain~ng the~ starches and dextrins h~v~ ~
~rookfield vi~co~ity of ~pproximately 500~5~00 cps.~ and they are u~ea in all appllcation~ including ~ide ~eams and ~ippi ng. A side seam i8 the b~nd produced to factlitate tke formatio~ of the tobacco filled ci~arette rod. Tippinc i~ the proce~s by which the separate filter section is ccmbi~ed with the ~ob~co filled ~ectlon by ~eans of an cverlapping bond.
Co~venti~al re~oi~tena~le envelope adhesi~e~
are prepared by the addition of dex~rin, plasticizer and other ~ddltive~ to dextrin-emulsi~ied ~inyl acetate h~mopolymers or copolym~rs. The remoisten~ble adhe~ive can compri~e an aque~u~ emul~ion of an ethylene-vinyl ace~ate poly~er, an e~ul~ifier or a protective colloid, a dex~ , and the ~hermally-~nh~h~ted ctarch. These .~ , NB1370~

a~O ~

J r ~ v~ L ~ S ~ ~ S . ) ~ ~ t ~ S i J J ~ ~J J L .~

R: 3PLACEMENT PAGE
24~
a~he~iv~s arf: char~c~er~ized by ~uperior drying speed~ and high glos~ roperties p~rticul~rly de~irable for 3uch appli~tions .
i N~ 3 70S8 . 1 ,~MEtJDEO SHE~ , 2 5 R~3PLAC~3ME~r PAG~
Co ~u~ating ~dhesi~e~ are p~epared u~i~g star~h, wate~, alkaii, and other op~ic~al ingredients, e.g., a ~ate~pr~c~ing ~ent. The corrugatin~ adhe~i~e3 compri~e wat3r, an alkali, a gelatinized t~ermally~
inhibited ca-rier s~arch, and ~n ungelatinized ~tarch.
Alternati~el r, the cor~ug~ting adhe9i~re~ comprise water, an alkali, a gel~tin~ zed carrier ~tarch, and an ungel~tinize~l ther~lly-inhibited ~tarch. The thermally inhibited ge:.atinized carrier ~tarch can be selected from t~e group co~lsi~ti~ of corn, ~igh amylo3e ~rn, pctato, wheat ~d ml:~tures therec~. Ctarches used a~ the caYrier portion may tontai~ portio~s or mixtures of high amylo~e st~rch. A m.xture of corn starch and hi~h amylo3e corn ~tar~h ~an b~ u~ed.
Ad~.esiY~ are also u~ed for b~ttle labelling, tukewinding, lay flat ~amin~ting, ~nd ti~sue/to~el and dispo~able ~2ticle~.
Env~Qpe ~dh~iv~
The dextrins utiliz~d in t~e en~elope ad~e~i~es may ~e deri~ed ~rom any a~ailable ~tarch ba~e in~luding, but not limited to, waxy ~aize, waxy sorgh~m, sago, tapioca, po~a~o, corn, ~or~hum, rice and wheat a3 well a3 t~e deriva~i~ e~ there~f . In ~11 ins~ances ~he starch b~3e ~houl~ ~e in un~elatirlized fo~m and ~hould remain in that ~orrn throughcut the ~ubsequerlt dex~rinization proces~ .
In ~on~erting these starch base~ into dex~rins, one may em~loy any o~ th~ usual dextri~izatio~ procedure~
well known t~ ~hose ~killed in the art, l~cludi~
tre~tment of 3~arch wl~h either heat or acid. It ~hould ke n~ed that when referen~e i8 made to "d~xtrins, l~ it in~lude~ the legraded st~rch produc~ ~ prepared ei~her by me~n~ of a pr,~ce~ whereirl the appliea~le gtarches are c~nverted Wit l ~cids and/or oxidizing a~ents, in the NB~.37~91~ . 1 AMENDEDS~~EJ

J rL~ o~ V~ I ~ ~ r I ~ + ~J U~ 3'J-L ~;5: ~ 3 R~PLA~EM3NT PAG~

pregence of ~a~cer, at superatmo~ph~ri~ pressures ar~d t~mpe~ature~ exce~ of about 212~F~ ~r by mean~ af enzy~;~e conve~.~ion procedure9 u~ilizing an enzyme such a~
alpha-amylas~. Addition~l in~ormatio~ relatiIlg to the dextrinizatic n of ~arche3 m~y be ~ound Chapters XII-XIII
of IlChe~istr~ ~n~ Industry o~ Starc~" edited by R.W.
Ke~r, publis~ed ir~ l~SO by the Acade~ic Press of New York, New Yo~k.
Th~ ~dheai~e polymer ba3e i~ prepared by conventi~al ethyle~e ~inyl acetate polymerization ....
.

N~137QS~8. 1 CA 022l04~ l997-07-24 ~MENDEDSHEETI , wos6/23038 PCT~Ss6/00988 When used in the final adhesive composition, the dextrin will be present in an amount up to about 40%, typically about 8-25%, preferably 15-20%, by weight of the formulation, with the humectant and dextrin-emulsified ethylene vinyl acetate re~in comprising therem~i n~r of the composition. Various optional additives, such as plasticizers, preservatives, thic~n~rs, bleaching agents, and the like may also be ~ t in the adhesive compositions in order to modify certain characteristics thereof.
Although the humectant component and the optional additional dextrin have been referred to as being "post-added," it should be recognized that the post-addition is merely the most convenient and generally accepted method of formulating "front" seal adhesives and that it is possible to add the humectant and the additional dextrin directly to the monomer charge prior to the actual polymerization.
Corrugating Adhesives The pro~el~res employed in the production of CUL L ~ated paperboard usually involve a continlloll~
e_s whereby a strip of paperboard is first corrugated by means of heated, fluted rolls. The ~Lo~L~ding tips on one side of this fluted paperboard strip are then coated with an adhesive, and a flat sheet of paperboard, commonly known in the trade as facing, is thereafter applied to these tips. By applying heat and pressure to the two paperboard strips thus brought together, an adhe~ive bond is formed. The above-described proçel .e pro~-~ceC what is known as a single-faced board in that the facing is applied to only one surface. If a double-faced paperboard is desired, in which an inner fluted layer is sandwiched between two facings, a cecon~
operation is performed wherein the adhesive is applied to the eY~oso~ tips of the single-faced board and the CA 022104~ 1997-07-24 W096/23038 - PCT~S9~J'~

proceJ~es with the one difference being the use of an aqueous solution of dextr,in as the emulsifier or protective colloid. The polymerization is then carried out in an aqueous medium under pressures less than about 130 atmospheres in the presence of a catalyst. If necefiCAry~ the system is main~in~A at a pH of 2 to 6 by using a suitable buffering agent. The polymerization is performed at conventional temperatures from about 70~ to 225~C, preferably from 120~ to 175~F, for sufficient time to achieve a low monomer content, e.g., from about 1 to 8 hours, preferably from 3 to 7 hours, and produces a latex having less than 1.5%, preferably less than 0.5% by weight of the free monomer. Conventional batch, semi-continuous or continuous polymerization procedu~e_ may be employed. See, for example, U.S. 3 708 388 (issued January 2, 1973 to Iacoviello et al.) and U.S. 4 164 488 (issued August 14, 1979 to Gregorovich et al.).
In addition to the required dextrin solution used as a protective colloid, other emulsifiers, generally of a non-ionic or anionic oil-in-water variety may also be used in the polymerization reaction. When used, the emulsifiers are generally present in amounts of 0.1 to 1% of the monomers used in the polymerization and is added either entirely to the initial charge or A~AeA
continuously or intermittently during polymerization or as a post-reaction stabilizer.
The preferred polymerization proce~llre is a modified batch processing wherein the major amounts of some or all the comonomers and emulsifier are charged to the reaction vessel after polymerization has been initiated. It is preferred to add the vinyl ester intermittently or continuously over the polymerization period of about 0.5-10 hours, preferably 2-6 hours.
The lattices are proAIlc~ and used at relatively high solids contents, e.g., between 35 and CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 waxy maize, sorghum, wheat, as well as high-amylose starches, i.e., starches which contain 40% or more by weight of amylose, and the various derivatives of these starches. Suitable starches include various starch derivatives such as ethers, esters, thin-boiling starches prepared by known processes such as mild acid treatments or oxidation, high amylose starch derivatives. Preferred starches are those typically employed in alkaline corrugating adhesives.
The starch content of the adhesive can vary considerably dep~n~in~ on several factors such as the in~ e~ end-use and the type of starch used. The total amount of starch employed, including the gelatinized and ungelatinized portions of starch, ordinarily will be in the range of about 10-40% by total weight of the adhesive.
The remainder of the adhesive composition is composed of about 0.3-5% of an alkali such as sodium h~dLoxide, h~e~ on total weight of starch, about 0.3-10%
on dry basis of an optional crosslinking additive tbased on total weight of starch), and about 54-89% of water h~ on total weight of the adhesive. The preferred amounts of all ingredients are 10-35% starch, 1-4%
~lk~l i, 60-81% water and, if used, 1-5% of the crosslinkin~ additive. A suitable crosslinkin~ additive is described in U.S. 4 366 275 (issued December 28, 1982 to M.A. Sitano et al.).
The alkali employed herein is preferably sodium l~d,oxide; however, other bases may be employed as partial or full replacement of the sodium hydroxide and include, for example, alkali metal hydLoxides such as potassium hydLoxide, alkaline earth hyd~oxides such as calcium l.yd~oxide, alkaline earth oxides such as barium oxide, alkali metal carbonates such as sodium carbonate, CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 75%, al~ho~gh they may be diluted with water if desired.
The preferred total solids are about 40-70%, most preferably about 50-68%, by weight. When used herein the term "solids" refers to the combined amounts of ethylene vinyl acetate resin, dextrin and other non-volatiles ~L e~-ent in the latex.
The particle size of the latex can be regulated by the quantity and type of the emulsifying agent or agents employed. To obtain ~maller particles sizes, greater amounts of emulsifying agents are used. As a general rule, the greater the amount of the emulsifying agent employed, the smaller the average particle size.
The humectant used herein may be any of those conventionally used in formulating remoistenable "front seal" adhesives, typically sugars, sorbitol, glycerine, ~L o~ylene glycol, and glycol ethers. These humectants are used in the adhesive formulations at levels of about 0.5-5% by weight of the total adhesive formulation.
In preparing the adhesive composition, an aqueous solution of the dextrin is prepared and ~AA~A to the ethylene vinyl acetate latex or the dry dextrin is ~AAe~ directly to the latex. The adhesive composition is then heated and maint~;ne~ at a temperature of about 160~-180~F with agitation for a period sufficient to ensure complete dissolution. Any other additives which are to be employed are added at this point. The resulting mixture is then diluted with additional water, if neC~cc~ry~ to the desired viscosity, generally in the range of about 2,000 to 11,000 cps, preferably about 6,000 cps. In the embodiment wherein dextrin is not post-added, it may be n~eCc~ry to add a thicken~r (e.g., polyacrylamide, carboxymethyl cellulose, or 11YdL oxyethyl cellulose) in order to obtain a viscosity within these limits.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 ratio of 5.5-6.5:1. Moisture content of all pregelatinized samples after spray drying and before the dehydration step in the thermal inhibition process was 4-10%.
For the samples pregelatinized by drum drying the pH was raised by slurrying the starch or flour in water at 30-40% solids and adding a sufficient amount of a 5% sodium carbonate solution until the desired pH was reached. A single steam-heated steel drum at about 142-145~C was used for the drum drying.
For the samples pregelatinized by the continuous coupled jet-cooking/spray-drying process of U.S. 5.131,953 or the dual atomization/spray-drying ~ LS of U.S. 4.280.851, the starch or flour was slurred at 6-10% solids in water and the pH was adjusted to the desired pH by A~ ing a sufficient amount of 5%
sodium carbonate solution until the desired pH was reached.
Exce~ where a conventional oven or dextrinizer is specified, the test samples were dehydrated and heat treated in a fluidized bed reactor, model number FDR-lOO, manufa~uLed by Procedyne Corporation of New Brunswick, New Jersey. The cross-sectional area of the fluidized bed reactor was 0.05 s~ meter. The starting bed height was 0.3-0.8 meter, but usually 0.77 meter. The fluidizing gas was air except where otherwise indicated.
When gr~nt~l~ non-pregelatinized starches were being heat treated, the gas was used at a velocity of 5-15 meter/min. When pregelatinized granular starches were being heat treated, the gas was used at a velocity of 15-21 meter/min. The side walls of the reactor were heated with hot oil, and the fluidizing gas was heated with an electric heater. The samples were loaded into the reactor and then the fluidizing gas in~o~ c~, or the samples were loaded while the fluidizing gas was being CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 adhesive-coated tips are then pressed against a Q~con~
facing in the combining section of the corrugator under the influence of pressure and heat. A typical corrugating process and the use and operation of corrugators are described in U.S. Pat. Nos. 2.102 937 and 2.051.025 (to Bauer).
The particular adhesive employed in the corrugating process is selected on the basis of several factors, including the type of bond required in the final application of the f;n;~he~ corrugated product. Starch-hA~~~ adhesives are most commonly used due to their desirable adhesive properties, low cost and ease of preparation.
The most fundamental of starch corrugating adhesives is an alkaline adhesive which is comprised of ungelatinized starch susp~n~e~ in an aqueous ~icpersion of cooke~ starch. The adhesive is pro~llceA by gelatinizing starch in water with sodium hydroxide (caustic soda) to yield a primary mix of gelatinized or rooke~ carrier starch. The cooke~ carrier starch is then slowly added to a secondary mix of ungelatinized starch, borax and water to produce the full-formulation adhesive.
In the corrugating process, the adhesive is applied (usually at between 25~ and 55~C) to the tips of the fluted paper medium or single-faced board. Upon the application of heat the ungelatinized starch gelatinizes, ting in an instantaneous increase in viscosity and the formation of the adhesive bond.
The starch component, which may be an ungelatinized starch and/or a gelatinized carrier starch may be selected from any of the several starches, native - or converted, heretofore employed in starch corrugating adhesive compositions. The ungelatinized starch is usually corn starch. Other suitable starches include, for example, those starches derived from corn, potato, CA 022104~ 1997-07-24 W096/23038 PCT~S96100g88 The starch slurry is heated rapidly to 92~C and held for 10 minutes. The peak viscosity and viscosity ten minutes after peak viscosity were recorded in BrAh~nA~r Units (BU). The percentage breakdown in viscosity (+ 2~) was calculated according to the formula:

% Breakdown = peak - (peak ~ 10') x 100, peak where "peak" is the peak viscosity in BrAh~ndPr units, and "(peak ~ 10')" is the viscosity in BrAh~n~çr Units at ten minutes after peak viscosity. If no peak viscosity was reached, i.e., the data indicate a rising (ris.) curve or a flat curve, the viscosity at 92~C and the viscosity at 30 minutes after attaining 92~C were recorded.
Using data from the BrAh~n~r curves, inhibition was determined to be present if, when ~i~p~rsed at 5~ or 6.3% solids in water at 92-95~C and pH

3, during the BrAh~n~r heating cycle, the BrAh~n~r data showed (i) no or almost no viscosity, indicating the starch wa~ so inhibited it did not gelatinize or ~r onyly resisted gelatinization; (ii) a continuous rising viscosity with no peak viscosity, indicating the starch was highly inhibited and gelatinized to a limited extent;
(iii) a lower peak viscosity and a lower percentage breakdown in viscosity from peak viscosity compared to a nL~ol, indicating a moderate level of inhibition; or (iv) a slight increase in peak viscosity and a lower percentage breakdown compared to a ~o~ ol, indicating a low level of inhibition.
Characterization Of Inhibition of Non-Preqelatinized Granular Starches BY Br~h~n~er Curves Characterization of a thermally-inhibited starch is made more conclusively by reference to a measurement of its BrAh~n~er viscosity after it is ~;sr~rsed in water and gelatinized.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 and alkali metal silicates such as sodium silicate. The alkali may be employed in aqueous or solid form.
Sample Preparation Unless indicated otherwise, all the starches and flours used were provided by National Starch and Chemical Company of Bridgewater, New Jersey.
The collL~ols for the test samples were from the same native source as the test samples, were unmodified or modified in the same manner as the test samples, and were at the same pH unless otherwise indicated.
All starches and flours, both test and control samples, were prepared and tested individually.
The pH of the samples was raised by slurrying the starch or flour in water at 30-40~ solids and ~;ng a sufficient amount of a 5% sodium carbonate solution until the desired pH was reached.
Measurements of pH, either on samples before or after the thermal inhibition steps, were made on samples consisting of one part starch or flour to four parts water.
After the pH adjustments, if any, all non-gelatinized granular samples were spray dried or flash dried as conventional in the art (without gelatinization) to about 2-15% moisture.
After the pH adjustment, if any, slurries of the starches to be pregelatinized to gr~n~ r pregelatinized starches were i~.LLolllc~ into a pilot spray dryer, Type 1-KA#4F, from APV Crepaco, Inc., Dryer Division, Attleboro Falls, Massachusetts, using a spray nozzle, Type 1/2J, from Spraying Systems Company of Wheaton, Ill. The spray nozzle had the following configurations: fluid cap 251376, air cap 4691312. The low initial cold viscosity samples were sprayed at a steam:starch ratio of 3.5-4.5:1, and the high initial cold viscosity samples were sprayed at a steam:starch CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 measurement of the extent of pregelatinization. The higher the viscosity at 30~C, the grater the extent of grAn~ r swelling and hydration during the pregelatinization process.
Heating was continued to 95~C and held at that temperature for lO minutes.
The peak viscosity and viscosity lO minutes after 95~C were recorded in Brabender Units (BU). The percentage breakdown was calculated using the previous formula:
If no peak viscosity was reached, that is, the data indicated a rising curve or a flat curve, the viscosity at 95~C and the viscosity at 10 minutes after attA;ni~g 95~C were recorded.
Characterization of Inhibition of Pregelatinized Granular Starches bY Brabender Curves As ~;~c~ above, characterization of a thermally-inhibited starch is made more conclusively by reference to a measurement of its viscosity after it is ~isr~rsed in water and gelatinized using the instrument described above.
For pregelatinized granular starches, the level of viscosity when dispersed in cold water will be ~ep~n~nt on the extent to which the starch was initially cooke~ out during the pregelatinization process. If the granules were not fully swollen and hydrated during pregelatinization, gelatinization will continue when the starch is dispersed in water and heated. Inhibition was determined by a measurement of the starch viscosity when the starch was dispersed at 4.6% solids in water at pH 3 and heated to 95~C.
When the pregelatinized grAntll~r starch had a high initial cold viscosity, meaning it was highly rooke~
out in the pregelatinization process, the resulting BrAhen~er traces will be as follows: for a highly CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 inLLol~c~. No difference was noted in the samples in the order of loading. Unless otherwise specified, the samples were brought from ambient temperature up to no more than 125~C until the samples became anhydrous and were further heated to the specified heat treating temperatures. When the heating temperature was 160~C, the time to reach that temperature was less than three hours.
The moisture level of the samples at the final heating temperature was O%, except where otherwise stated. Portions of the samples were removed and tested for inhibition at the temperatures and times indicated in the tables.
These samples were tested for inhibition using the following Brabender Procedures.
BrAh~n~er Proc~ltlre -Non-Pregelatinized Granular Starches Unless other stated, the following BrAhen~r procGll-e was used. All samples, except for corn, tapioca and waxy rice flour, were slurried in a sufficient amount of distilled water to give a 5%
anhydLous solids starch slurry. Corn, tapioca, and waxy rice flour were slurried at 6.3% anhydrous solids. The pH was adjusted to pH 3.0 with a sodium citrate, citric acid buffer and the slurry was introAllce~ into the sample cup of a BrAhpnApr VISCO/Amylo/GRAPH (manufa~Led by C.W. BrAhen~r Instruments, Inc., Hacken~Ack, NJ) fitted with a 350 cm/gram cartridge. The VISCO\Amylo\GRAPH
records ~he torque required to h~l ~nce the viscosity that develops when a starch slurry is subjected to a -ammed heating cycle. The record consists of a curve tracing the viscosity through the heating cycle in arbitrary units of measurement termed BrAh~n~r Units (BU)-CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 is occurring at a slow rate and to a limited extent; for a less inhibited starch, the trace will ~how a dropping curve, but the overall breakdown in viscosity from the peak viscosity will be lower than that for a non-inhibited cGI.L~ol.
Brabender Procedure - Crosslinked Starches The crosslinked, thermally-inhibited cationic and amphoteric starches (23.0 g) to be tested was combined with 30 ml of an aqueous solution of citric acid monohydrate (prepared by diluting 210.2 g of citric acid monohydrate to lOOO ml in a volumetric flask) and sufficient water was added to make the total charge weight 460.0 g. The slurry is added to the cooking chamber of the Br~he~er VISCO amylo GRAPH fitted with a 700 cm/gram cartridge and rapidly heated from room temperature to 95~C. The peak viscosity (highest viscosity observed) and the viscosity after 30 minutes at 95~C were recorded. The percentage breakdown in viscosity (+2%) was calculated according to the formula~0 % Breakdown = Peak - (ViscositY after 30' at 95~C) x lOO
Peak Characterization of Inhibition bY Cooks A dry blend of 7 g of starch or flour (anhydrous basis) and 14 g of sugar were added to 91 ml of water in a Waring blender cup at low speed, then transferred to a cook-up h~ker~ allowed to stand for lO
minutes, and then evaluated for viscosity, color, clarity and texture.
Some of the granular non-pregelatinized starch samples were tested for pasting temperature and/or gelatinization temperature using the following procedures.
RaPid Visco Analyzer fRVA) This test is used to determine the onset of gelatinization, i.e., the pasting temperature. The onset CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 For non-inhibited starches, the cycle passes through the initiation of viscosity, usually at about 60-70~C, the development of a peak viscosity in the range of 67-95~C, and any breakdown in viscosity when the starch is held at an elevated temperature, llc?l~lly 92-95~C.
Inhibited starches will show a BrAh~n~r curve different from the curve of the same starch that has not been inhibited (hereinafter the control starch). At low levels of inhibition, an inhibited starch will attain a peak viscosity somewhat higher than the peak viscosity of the control, and there may be no decrease in percentage breakdown in viscosity compared to the control. As the amount of inhibition increases, the peak viscosity and the breakdown in viscosity decrease. At high levels of inhibition, the rate of gelatinization and sw~ll;ng of the granules decreases, the peak viscosity ~;CArrears, and with prolonged cooking the BrAh~n~er trace becomes a rising curve indicating a slow continuing increase in viscosity. At very high levels of inhibition, starch granules no longer gelatinize, and the BrAh~n~r curve remains flat.
BrAh~n~er Procedure - Pregelatinized Granular and Non-Granular Starches The pregelatinized thermally-inhibited starch to be tested was slurried in a sufficient amount of distilled water to give a 4.6% anhydrous solids starch slurry at pH 3 as follows: 132.75 g sucrose, 26.55 g starch, 10.8 g acetic acid, and 405.9 g water were mixed for three minutes in a stAnAArd home Mixmaster at setting #1. The slurry was then il.L~Gl~c~ to the sample cup of a BrAh~n~r VISC0/Amylo/GRAPH fitted with a 350 cm/gram cartridge and the viscosity measured as the slurry was heated to 30~C and held for 10 minutes. The viscosity at 30~C and 10 minutes after hold at 30~C were recorded.
The viscosity data at these temperatures are a CA 022104~ 1997-07-24 W096123038 PCT~S96/00988 The viscometer is turned on and the spindle is rotated at a constant speed (e.g., 10 or 20 rpm) for at least 3 revolutions before a reading is taken. Using the appropriate conversion factors, the viscosity (in centipoises) of the sample is recorded.
EXAMPLES
The following examples will more fully illustrate the embodiments of this invention. In the examples, all parts are given by weight and all temperatures are in degrees Celsius unless otherwise noted. The thermally-inhibited starches and cullLLols in the following examples were prepared as described above and are defined by textural characteristics or in relation to data taken from Brabender curves using the above-described proce~ll~es. Unless otherwise specified, the thermally-inhibited starches and flours referred to as "granular" starches are non-pregelatinized granular starches and flours.
The thermally-inhibited starches and flours are referred to as "T-I" starches and flours and the conditions used for their preparation (i.e., pH to which the starch is adjusted and heat treatment temperature and time at that temperature) are included in parenthesis (pH;temperature/hold time at that temperature). All pH
adjustments are done with sodium carbonate unless specified otherwise.
In the first three examples to follow, the moisture indicated is the moisture content in the starch before the dehydration and heat treating steps. As indicated above, as the starches were brought from ambient temperature up to the heating temperature, the ~tarches became anl.~dL~s or substantially anhydrous.
In the tables the abbreviations "sl.", "mod.", "v.", "ris." and "N.D." stand for slight or slightly, moderate or moderatly, very, rising, and not determined.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 inhibited that the starch, the trace will be a flat curve, indicating that the starch is already very swollen and is so inhibited starch it is resisting any further gelatinization or the trace will be a rising curve, indicating that further gelatinization is occurring at a 810w rate and to a limited extent; for a less inhibited starch, the trace will he a dropping curve, indicating that some of the granules are fragmenting, but the overall breakdown in viscosity will be lower than that for a non-inhibited control or the trace will show a cecQnA peak but the breakdown in viscosity will be lower than that for a non-inhibited control.
When the pregelatinized starch had a low initial cold viscosity, meAn;ng it was not highly cooked out in the pregelatinization process and more co~king is n?~~ to reach the initial peak viscosity, the resulting Br~h~n~e~ traces will be as follows: for a highly inhibited starch, the trace will be a rising curve, indicating that further gelatinization is occurring at a slow rate and to a limited extent; for a less inhibited starch, the trace will show a peak viscosity as gelatinization occurs and then a drop in viscosity, but with a lower percentage breakdown in viscosity than for a non-inhibited control.
If no peak viscosity was reached, that is, the data indicated a rising curve or a flat curve, the viscosity at 95~C and the viscosity at 10 minutes after att~ining 95~C were recorded.
Characterization of Inhibition of Pregelatinized Non-Granular Starches of Brabender Curves The resulting Brabender traces will be as follows: for a highly inhibited starch the trace will be flat, indicating that the starch is so inhibited that it is resisting any further gelatinization or the trace will be a rising curve, indicating that further gelatinization CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 4 8.2 10.6 4 heavy to v. sl. to heavy mod.
cohesive 8.2 10.6 4.5 heavy non-cohesive 6 8.2 10.6 5.5 heavy, non-th; nnP~t cohesive 7 8.2 10.6 6 mod. heavy non-cohesive unmod- -- -- v. heavy cohesive ifiedb cross- -- -- v. heavy non-linkedC cohesive a. All samples were commercial samples of gr~nlll Ar waxy maize starch obt~; neA from National Starch and Chemical Company, Bridgewater, New Jersey.
b. The unmodified cv~ ol was a commercial gr~mllAr waxy maize starch obt~; n~A from National Starch and Chemical Company, Bridgewater, New Jersey.
c. The modified control was a commercial crosslinked (phosphorous oxychloride treated) granular waxy maize starch obt~;neA from National Starch and Chemical Company, Bridgewater, New Jersey.
d. Samples were cooked by slurrying 7.0 g of starch (at 12% moisture) in 91 mls water at neutral pHs and heating the starch slurry for 20 minutes in a boi~ing water bath.
e. The cold evaluation was carried out at 25 C.

CA 022104~ 1997-07-24 W096t23038 PCT~S96/00988 of gelatinization is indicated by an increase in the viscosity of the starch slurry as the starch granules begin to swell.
A 5 g starch sample (anhydrous basis) is placed in the analysis cup of a Model RVA-4 Analyzer and slurried in water at 20% solids. The total charge is 25 g. The cup is placed into the analyzer, rotated at 160 rpm, and heated from an initial temperature of 50~C up to a final temperature of 80~C at a rate of 3~C per minute.
A plot is generated showing time, temperature, and viscosity in centipoises (cP). The pasting temperature is the temperature at which the viscosity reaches 500 cP.
Both pasting temperature and pasting time are recorded.
~ifferential ScAn~;nq Calorimetry (DSC) This test provides a quantitative measurement of the enthalapy (~H) of the energy transformation that occurs during the gelatinization of the starch granule.
The peak temperature and time required for gelatinization are recorded. A Perkin-Elmer DSC-4 differential CcAnn;ng calorimeter with data station and large volume high pressure sample cells is used. The cells are prepared by weighing accurately lO mg of starch (dry basis) and the a~p~o~iate amount of distilled water to a~lGximately equal 40 mg of total water weight (moisture of starch and distilled water). The cells are then sealed and allowed to equilibrate overnight at 4~C before being scanned at from 25-150~C at the rate of 10~C/minute. An empty cell is used as the blank.
Brookfield Viscometer Procedure Test samples are measured using a Model RVT
8rookfield Viscometer and the appropriate spindle (the spindle is selected based on the anticipated viscosity of the material). The test sample, usually a cooked starch paste or dextrin, is placed in position and the spindle is lowered into the sample to the appropriate height.

CA 022104~ 1997-07-24 W096/23038 PCT~3~6/

TABLE III - Process Variables Cold Evaluation of Sam~lea Heatinq - 160~C Gelatinized Sampleb Mois-E~ ture ~ ViscositY/Texture (%) (hrs.) Waxy BarleY Starch 1 8.7 8.5 1.5 heavy cohesive 2 8.7 8.5 2.5 heavy sl. mod.
cohesive 3 8.7 8.5 3.5 mod. heavy non-to heavy cohesive 4 5.2 10.8 1.5 thin --5.2 10.8 2.5 thin/ --~hi~n~t Waxy -- -- 0 heavy cohesive Barley CG~ILr ol Tapioca Starch 6 8.8 10.3 2 heavy to v. cohesive heavy 7 8.8 10.3 3 heavy to v. cohesive/
heavy less than Sample 6 8 8.8 10.3 4 heavy to v. sl.
heavy cohesive to sl.
lumpy W096/23038 PCT~S96/00988 This example illustrates the preparation of the starches of this invention from a commercial granular waxy maize base starch by the heat treatment process of this invention.
Processing conditions and their effects on viscosity and texture of waxy maize starch are set forth in the Tables below.
To obtain a heat-stable, non-cohesive thickener, samples of granular starch were slurried in 1.5 parts of water, the pH of the slurry was adjusted with the addition of a 5% Na2CO3 solution and the slurry was agitated for 1 hour, then filtered, dried, and yL OUl.d . The dry starch samples (150 g) were placed into an aluminum foil pan (4" x 5" x 1-1/2") and heated in a conventional oven under the conditions described in Tables I and II. Br~hen~r viscosity measurements demonstrated that the most heat-stable starches were ob~i n~ by heating at 160-C and a pH of at least 8.0 for about 3.5 to 6.0 hours.
TABLE I - Process Variables Waxy Cold Evaluation of Maizea Heating - 160~CGelatinized Sam~lesd~e Mois-E~ ture Time ViscositY Texture (%) (hrs.) 1 6.0 lO.9 2 heavy to v. cohesive heavy 2 6.0 lO.9 4thin to mod. --3 8.2 10.6 3.5 heavy to v. cohesive, heavy less than unmodified control CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 TABLE IV - Process Variables Cold Evaluation of SampleaHeating - 160~C Gelatinized Sampleb Mois-E~ ture Time Viscosity/Texture (%) (hrs.) V.O. Hybrid Starch 1 8.7 10.5 2.0 heavy cohesive v.
sl. less than control 2 8.7 10.5 3.0 heavy sl. mod.
cohesive 3 8.7 10.5 4.0 mod. heavy smooth, to heavy very sl.
cohesive 4 8.7 10.5 5.0 mod. heavy smooth, short, non-cohesive 8.7 10.5 6.0 moderate smooth, short, non-cohesive V.O. 5.9 11.4 O heavy cohesive Hybrid Col,~rol a. V.O. hybrid starch samples were granular starches obt~; ~eA from National Starch and Chemical Company, Bridgewater, New Jersey.
b. Samples were cooked by slurrying 7.5 g of starch at 12% moisture in lOO mls of water and heating the starch slurry for 20 minutes in a boiling water bath.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 TABLE II - Brabender Evaluation Waxy BrAh~nA~r Maizea Process Variables Viscosityb (BU) Viscosity Heating Peak at 95~C/
E~ Temp. Time Viscosity 20 mins.
(~C) (hrs.) 3 8.2 160 3.5 985 830 4 8.2 160 4.0 805 685 8.2 160 4.5 640 635 6 8.2 160 5.5 575 570 Unmodified -- none none 1640 630 ~ol.L~ol 1 6.0 160 2.0 1055 560 2 6.0 160 4.0 140 80 a. See Table I for a description of samples.
b. In the BrAh~ r pro~ re, a sample cont~in;ng 5.4%
anhydrous solids of starch dispersed in water was heated rapidly to 50~C, then the heat was increased by 1.5~C per minute to 95~C, and held for 20 minutes.

This example illustrates that a variety of gr~ntll ~r starches may be processed by the method of this invention to provide a non-cohesive thickener with properties similar to chemically crosslinked starches.
Processing conditions and their effects on the viscosity and texture of waxy barley, tapioca, VØ
hybrid and waxy rice starches are set forth in the tables below.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Waxy Process Cold Evaluation of Maizea Variablesb Gelatinized StarchC
Heat Time ViscositY Texture (hrs.) 1. Test 16 heavy, sl. cohesive (20-4~ H20) thinner than ~Gll LL ol 4. Control 0 heavy cohesive (12.1% H20) 5. Test 7 heavy cohesive (20.4~ H20) 6. Control 0 heavy cohesive (12.1% H20) a. Samples were obt~;n~A from National Starch and Chemical Company, Bridgewater, New Jersey.
b. Process was con~lcted at pH 5.2.
c. See Table III for cook conditions.
The results demo-.~LLate that moisture ~
during the process yields a product which is as cohesive and undesirable as a o~llLLol starch which had not been heated.
Part B
Samples (900 g) of a commercial granular waxy maize starch (obt~i n~ from National Starch and Chemical Company, Bridgewater, New Jersey) were placed in a 10" x 15" x 0.75" aluminum tray and heated in an oven at 180-C
for 15, 30, 45 and 60 minutes. The pH of the starch was not adjusted and remained at about 5.2 during the heating process. Sample viscosity and texture were evaluated by the method of Example 1.
As shown in Table VI, below, the pH 5.2 samples were characterized by an undesirable, cohesive texture CA 022104~ 1997-07-24 W096/23038 PCT/U~5~/00988 9 8.8 10.3 5 heavy non-cohesive lumpy 5.5 10.9 3 mod. heavy --Tapioca -- -- 0 v. heavy cohesive Control 5 Waxy Rice Starch 1 9.1 9.0 2 v. heavy cohesive 2 9.1 9.0 3 heavy sl.
cohesive 3 9.1 9.0 4 heavy sl.
cohesive 4 9.1 9.0 5 mod. heavy non-to heavy cohesive 10 Waxy -- -- 0 v. heavy cohesive Rice CG11l,~ ol a. Tapioca starch samples were commercial gr~n~ r starch obt~in~ from National Starch and Chemical Company, Bridgewater, New Jersey. Waxy barley starch samples were commercial granular starch obt~;ne~ from AlKo, Finland. Waxy rice starch samples were commercial granular starch obtAine~
from Mitsubishi Corporation, Japan.~0 b. Samples were cooked by slurring 7.5 g of starch at 12% moisture in 100 mls of water and heating the starch slurry for 20 minutes in a boiling water bath.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Viscosity (B.U.) Heating Tem~erature and Time Peak Break-peak + 10'down (%) Control (none) 1135 730 64.3 110~C for 22 hrs. 1185 970 18.1 160~C for 0 hr. 1055 880 16.6 160~C for 2 hrs. 665 660 0.7 175~C for 0 hr. 850 755 11.2 180~C for 0 hr. 715 680 4.9 190~C for 0 hr. 555 550 0.9 200~C for 0 hr. ris. -- --200~C for 2 hrs. none -- --The data shows that inhibited anhydrous or substantially anhyd~ GUS samples can be obtAin~A at heat treating temperatures between 100-200~C, with more inhibition obtA;n~ at higher temperatures or at longer times at lower temperatures. The starch samples heated at 200~C were highly inhibited (rising curves) or completely inhibited (no gelatinization).

Samples of a high amylose starch (Hylon V - 50%
amylose) at its natural pH and pH 9.5 were evaluated for the effect of the high amylose content on inhibition.
The starches were thermally-inhibited at 160~C in the fluidized bed for the indicated time. Due to the high levels of amylose, it was nPc~ccAry to use a pressurized Visco/amylo/Graph (C.W. BrAhPn~er~ HackencAck, NJ) to obtain BrAhen~r curves. Samples were slurried at 10%
starch solids, heated to 120~C, and held for 30 minutes.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 The viscosity and texture evaluation results show that a non-cohesive, heat-stable starch thickener may be prepared from waxy barley, V.O. hybrid, tapioca and waxy rice starches by the process of this invention.
The amount of inhibition (non-cohesive, thicken;n~
character in cooke~ aqueous dispersion) increased with increasing time of heat treatment.

This example illustrates the effects of temperature, the pH, and starch moisture content on the viscosity and texture of the treated starch.
Part A
A waxy maize starch sample (lOO g) contA;n;ng 20.4% moisture was heated in an oven at lOO-C for 16 hours in a sealed glass jar. A ceco~ sample was heated for 4 hours and a third sample was heated for 7 hours under the same conditions. The product viscosity and texture were compared to a 12.1% moisture granular waxy maize starch control using the cook evaluation method of~0 Example 1, Table I. Results are shown in Table V, below.
TABLE V - Effect of Process Moisture Waxy Process Cold Evaluation of Maizea Variablesb Gelatinized StarchC
Heat Time ViscositY Texture (hrs.) 1. Test 16 heavy, sl. cohesive (20.4% H2O) thinner than control 2. CollLrol O heavy cohesive (12.1% H2O) 3. Test 4 heavy cohesive (20.4% H2O) CA 022104~ 1997-07-24 W096/23038 PCT~Ss6/oo988 Heat Treatment Conditions viscositY (B.U.) 30~C 95~C Break-30~C+ 10' Peak 95~C + 10' down ) ~ 6.0 - High Initial Viscosity Control 1280 960 960170 90 91 160~C for 0 min. 700 980 700610 370 47 160~C for 30 min.600 910 720690 370 49 160~C for 90 min.450 780 915740 400 56 160~C for 150 min.360 590 925800 500 46 ~H 6.0 - Low Initial Viscosity Control 230 250 750340 100 87 160~C for 30 min.100 130 600370 210 65 160~C for 60 min.100 140 730500 260 64 160~C for 120 min.100 130 630430 260 S9 160~C for 180 min.90 120 550390 240 56 ~H 8.0 - High Initial Viscosity Control 1400 1020 1020 270 100 90 160~C for 0 min.700 1060 1050 760 280 73 160~C for 60 min.260 600 13401200780 42 160~C for 90 min.240 440 1280 1240 100022 160~C for 120 min.280 420 1320 1320 1280 3 160~C for 150 min.120 200 860860 820 7 160~C for 180 min.180 260 980980 920 8 PH 8.0 - Low Initial Viscosity Control 250 250 820340 130 84 160~C for 0 min. 50 100 690460 270 61 160~C for 60 min. 40 50 840590 320 62 160~C for 120 min.20 30 720650 450 38 160~C for 180 min.20 30 590570 450 24 30 PH 10 - High Initial Viscosity C~l.L~ol 1010 740 1010 300 160 84 140~C for 0 min. 550 850 1280 1080 750 41 150~C for 0 min. 270 420 1680 1680 1540 8 CA 022104~ 1997-07-24 W096t23038 PCT~S96/00988 similar to that of a waxy maize starch control which had not been heat treated.
TABLE VI - Effect of ~cidic Process pH
Process Cold Evaluation of SamPle Variablesa Gelatinized Starchb Heatinq Time Viscosity Texture (minutes) 1 15 v. heavy cohesive 2 30 v. heavy cohesive 3 45 v. heavy cohesive 4 60 heavy to cohesive v. heavy uo~ ol 0 v. heavy cohesive a. The pH was not adjusted from that of the native waxy maize starch (a pH = 5.2) and Samples 1-4 correspond to starch treated by the process of U.S. Pat. No. 4 303.4Sl (no pH adjustment).
b. See Table III for cook conditions.
Thus, a combination of selected factors, including the pH, moisture content and the type of native starch, determine whether a desirable, non-cohesive, heat-stable starch thickener is produced by the process of this invention.

This example shows carrying out the thermal inhibition in the fluidized bed previously described.
The effects of temperature and time at the indicated temperature on the level of inhibition of waxy maize grA~ r starch at pH 9.5 are shown below.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Cook Evaluation Heat Treatment Viscosity ~ Hours at 14Q~C of Cook Texture Q~ CQOk Waxy Maize 6 2 mod. sl. cohesive, smooth 6 4 mod. to thin sl. cohesive, smooth 6 6 mod. v. sl. cohesive, smooth 6 8 mod. v. sl. cohesive, smoQth 8 2 mod. cohesive, smooth 8 4 mod. to heavy sl. cohesive, smooth 8 6 mod. v. sl. cohesive, smooth 8 8 mod. v. sl. cohesive, smooth 2 mod. sl. cohesive, smooth 4 mod. to heavy non-cohesive, short, smooth 6 mod. non-cohesive, short, smooth 8 mod. non-cohesive, short, smooth Ta~ioca 6 2 mod. to heavy v. cohesive, long 6 4 mod. to heavy cohesive CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 The results are shown below:
Natural ~H~H 9.5 Viscosity (BU)Viscosity rBU) Peak Break-Peak Break-~eak + lQ' downPeak ~ 10' down (%)(%) Control 1180 525 55.5 1180 525 55.5 (0 min.) (120 min.) The data show that inhibition was ob~A; neA only on the high pH sample.

This example shows the preparation of pregelatinized granular, thermally-inhibited waxy maize starches. The pregelatinization step was carried out prior to the thermal inhibition. The fluidized bed described previously was used.
Starch slurries (30-40% solids), pH adjusted to 6, 8, and 10, were pregelatinized in a pilot size spray drier (Type-l-KA#4F, from APV Crepaco, Inc., Dryer Division, of Attle Boro Falls, M~c~chusetts) using a spray nozzle, Type 1/2 J, from Spraying Systems Company of Wheaton, Illinois. The spray nozzle had the following configuration: fluid cap, 251376, and air cap, 4691312.
The resulting high and low viscosity pregelatinized granular starches were dehydrated and heat treated at the temperature and time indicated. The ~ thermally-inhibited starches were evaluated for inhibition using the Br~h~n~er procedure previously de~cribed.
The results are shown below:

CA 022104~ 1997-07-24 W096/23038 PCT~Ss6/00988 8 8 mod. non-cohesive, v. sl.
set, smooth 2 heavy v. cohesive 4 heavy to mod. sl. cohesive, v. sl. set, smooth 6 heavy to mod. non-cohesive, short, mod. set, smooth 8 heavy to mod. non-cohesive, short, mod. set, smooth Heat Treatment Conditions ViscositY (BU) Breakdown 30~C 30~C+10' Peak 95~C95~C+10' (%) Waxy Maize at ~H 8 and 140~C
2 hrs 400 1115 1115 515515 60 6 hrs 400 955 1120 11201023 38 Tapioca at ~H 8 and 140~C
2 hrs 1140 2685 2685 2685880 78 6 hrs 370 800 1110 1110890 46 The results show that thermally-inhibited pregelatinized grAmllAr starches can be prepared using other starch bases and that for non-cohesive starches longer times and/or higher pHs are required when an oveno rather than a fluidized bed is used for the dehydration and heat treatment.

This example shows the preparation of pregelatinized, non-granular starches which were pregelatinized by drum-drying and then thermally inhibited.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 160~C for 0 min. 170 240 -- 1180 1440ris.
160~C for 30 min. 80 85 -- 410 650ris.
160~C for 60 min. 60 60 -- 150 300ris.
160~C for 90 min. 50 50 -- 80 140ris.
120~C for 120 min. 40 40 -- 80 130ris.
150~C for 150 min. 40 40 -- 60 90 ris.
160~C for 160 min. 40 40 -- 45 70 ris.
DH 1O - Low Initial Viscosity CollL~ol 200 190 615 350 190 69 130~C for 0 min. 110 180 1500 880 530 65 150~C for 0 min. 50 80 16701540 1250 25 160~C for 0 min. 30 30 -- 1040 1320 ris.
160~C for 30 min. 30 30 -- 380 640 ris.
160~C for 60 min. 30 30 -- 150 310 ris.
160~C for 90 min. lO 10 -- 50 120 ris.
The results show some thermal inhibition was at~Aine~ in all the dehydrated and heat treated pregelatinized grAnlllAr starches and that increasing the initial pH and the heat treatment time increased the level of inhibition. For the samples at pH 6.0, at 0 and 30 minutes, the recorded peak was actually a c~co~ peak obtained after the initial high viscosity began to breakdown. For some of the samples at pH 10, no peak viscosity was reached, indicating a highly inhibited starch.

This example describes the preparation of thermally-inhibited pregelatinized grA~ Ar starches from additional starch bases as well as a waxy maize starch.
The granular starches were adjusted to the indicated pH, pregelatinized using the ~.,cel~,e previously described, and heat treated in an oven at 140~C for the indicated time. The cook evaluation and Brabender results are shown below.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 8 hr~ heavy sl. cohesive, pulpy TaPioca - ~H 8 2 hrs heavy to v. heavy v. cohesive, pulpy 4 hrs heavy v. cohesive, pulpy 5 6 hrs N.D. N.D.
8 hrs heavy v. sl. cohesive, pulpy T~eioca lO - ~H
2 hrs heavy cohesive, pulpy 4 hrs heavy to v. heavy sl. cohesive, pulpy lO 6 hrs heavy non-cohesive, short, pulpy 8 hrs mod. heavy non-cohesive, short, pulpy Potato - pH 6 2 hrs heavy to v. heavy cohesive, pulpy 4 hrs heavy cohesive, pulpy 15 6 hrs mod. to heavy cohesive, pulpy 8 hrs mod. to heavy cohesive, pulpy Potato - pH 8 2 hrs heavy to v. heavy v. cohesive, pulpy 4 hrs v. heavy cohesive, pulpy 20 6 hrs v. heavy cohesive, pulpy 8 hrs v. heavy cohesive, pulpy Potato - pH lO
2 hrs heavy to v. heavy v. cohesive, pulpy 4 hrs v. heavy slight set, sl. chunky 25 6 hrs heavy slight set, sl. chunky CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 6 6 mod. sl. cohesive, smooth 6 8 mod. non-cohesive, short, smooth 8 2 mod. to heavy v. cohesive 8 4 mod. to heavy cohesive 8 6 mod. to heavy non-cohesive, short, smooth 8 8 mod. to heavy non-cohesive, short, smooth 2 mod. to heavy cohesive, long 4 mod. to heavy v. sl. cohesive, smooth 6 mod. non-cohesive, short, smooth 8 mod. to heavy non-cohesive, short, smooth PotatO
6 2 heavy to v. cohesive, long v. heavy 6 4 heavy cohesive 6 6 mod. to heavy sl. cohesive 6 8 mod. to heavy v. sl. cohesive 8 2 heavy to v. cohesive, long v. heavy 8 4 v. heavy sl. cohesive 8 6 heavy non-cohesive, sl. set, smooth CA 022104~1997-07-24 W096/23038 PCT~S96/00988 atomizer - centrifugal wheel. The pregelatinized non-granular starch was adjusted to pH 8.7 and dehydrated and heat treated for 8 hours in an oven at 140~C. The characteristics of the resulting thermally-inhibited starches are set out below.
Viscosity (BU) 30~C 30~C+10' Peak 95~C 95~C+10' Breakdown (%~
Co~lLLol 200 195 245 245 130 47 High 350 240 420 410 335 20 Amylose The results show that even a high amylose starch can be inhibited. There was less breakdown for the thermally-inhibited starch and the overall viscosity was higher.

The example shows that thermally-inhibited waxy maize starches can be prepared by drum drying the starches prior to thermal inhibition. The resulting non-gr~ r thermally-inhibited drum-dried starches are compared with the non-grAmll ~r thermally-inhibited waxy maize starches prepared by the continuous coupled jet-cooking and spray-drying process used in Example 8 and with granular thermally-inhibited starches prepared by the dual atomization/spray drying process described in U.S. 4,280.251 (which was used in Example 6). The conditions used for the oven dehydration and heat treatment were 8 hours at 140~C.
The characterization of the resulting thermally-inhibited pregelatinized starches is shown below.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Samples of waxy maize, tapioca and potato starches, at pH 6, 8, and 10, were pregelatinized by drum-drying. The samples were placed in a 140~C oven, dehydrated to anhydrous, and heat treated at 140~C for the indicated times.
The viscosity and textural characteristics of the thermally-inhibited starches are set out below.
Cook ViscositY Cook Texture Waxy Maize - ~H 6 10 2 hrs heavy v. cohesive, pulpy 4 hrs heavy to v. heavy cohesive, pulpy 6 hrs heavy sl. cohesive, pulpy 8 hrs mod. to heavy v. sl. cohesive, pulpy Waxy Maize - pH 8 15 2 hrs heavy v. cohesive, pulpy 4 hrs heavy sl. cohesive, pulpy 6 hrs mod. to heavy v. sl. cohesive, pulpy 8 hrs mod. to heavy v. sl. cohesive, pulpy WaxY Maize - ~H 10 20 2 hrs heavy cohesive, pulpy 4 hrs heavy to mod. v. sl. cohesive, pulpy 6 hrs mod. non-cohesive, short, pulpy 8 hrs mod. non-cohesive, short, pulpy Ta~ioca - pH 6 25 2 hrs v. heavy cohesive, pulpy 4 hrs heavy to v. heavy sl. cohesive, pulpy 6 hrs mod. heavy sl. cohesive, pulpy CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 80~C overnight to thermally dehydrate the starch to <1%
(o%) moisture. The other sample was placed in a Soxhlet extractor and allowed to reflux overnight (about 17 hours) with anhydrous ethanol (boiling point 78.32~C).
The ethanol-extracted sample was placed on paper so that the eYcecc alcohol could flash off which took about 30 minutes. The ethanol-extracted starch was a free flowing powder which was dry to the touch.
For the heat treatment, the oven-dehydrated starches and ethanol-extracted starches were placed on trays in a forced draft oven and heated for 3, 5, and 7 hours at 160~C.
The thermally-inhibited (T-I) starches and the controls were evaluated using the Brabender Procedu~e previously described was used. The results are shown below:
BRABENDER RESULTS
Viscosity (BU) Dehydra- Heat tion Treat- Peak Break-Method ment ~a~ + 10' down (160~C) (%) Waxy Maize (pH 5.3) Control -- -- 1245 330 74 Dehydrated oven -- 1290 350 73 Dehydrated ethanol -- 1205 245 80 T-I oven 5 hrs. 95 45 53 T-I ethanol 5 hrs. 255 185 28 T-I oven 7 hrs. 60 35 42 T-I ethanol 7 hrs. 165 105 36 CA 022104~ 1997-07-24 W096/~038 PCT~S96/00988 8 hrs mod. heavy moderate set, sl.
chunky Brabenders were run on some of the above starches. The results are shown below.
~ Viscosity fB.U.) 30~C 95~C Break-30~C+10' Peak 95~C +10' down (%) WaxY Maize - ~H 8 2 hrs. 6653000 46201120 300 94 6 hrs. 7001640 24452440 1900 22 Tapioca - pH 8 102 hrs. 15003170 3290 680 600 82 6 hrs. 11801870 1873 780 600 68 The results show that longer heating times and/or higher pHs are required to prepare non-cohesive starches at 140~C. It is expected that heating at 160~C, lS preferably in a fluidized bed, will provide non-cohesive starches.

This example shows the preparation of another pregelatinized non-granular starch which was jet-cooked, spray-dried, and then thermally inhibited.
A gr~n~ r high amylose starch (50% amylose) was jet-cooke~ and spray-dried using the con~; nllgll~
coupled jet-cooking/spray-drying process described in U.S. 5.131.953 and then thermally inhibited for 8 hours at 140~C. The jet-cooking/spray-drying conditions used were as follows: slurry - pH 8.5-9.0; cook solids - 10%;
moyno setting - about 1.5; cooking temperature - about 145~C; ~Ycecc steam - 20%; boiler pressure - about 85 p8i; back pressure - 65 psi; spray-dryer - Niro dryer;
inlet temperature - 245~C; outlet temperature - 115~C;

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 The Br~h~n~r results are shown below ViscositY (BU) Heat Treat-Dehydration ment Peak Break-Starch Method Time Peak +10' down Ta~ioca (pH 9.5 and 160~C) Dehydrated oven -- 745 330 58 Dehydrated ethanol -- 720 330 54 T-I oven 5 hrs. 270 260 3 T-I ethanol 5 hrs. 260 258 T-I oven 7 hrs. 110 155 ris.
T-I ethanol 7 hrs. 100 145 ri~.
Corn (pH 9.5 and 160~C) Dehydrated oven -- 330 280 15 Dehydrated ethanol -- 290 250 14 T-I oven 5 hrs. 10 80 ris.
T-I ethanol 5 hrs. 10 170 ris.
T-I oven 7 hrs. 10 65 ris.
T-I ethanol 7 hrs.10 45 ris.
Wax,y Rice (~H 9.5 and 160~C) Dehydrated oven -- 1200 590 50.8 Dehydrated ethanol -- 1155 450 61.0 T-I oven 5 hrs.518 640 ris.
T-I oven 7 hrs.265 458 ris.
T-I ethanol 7 hrs.395 520 ris.

CA 022104~ 1997-07-24 WO 96/23038 PCr/US96/00988 Drum-Pried/Non-Granular T-I Waxy Maize (~H 8) Viscosity fBU) 30~C 30~C+10 ' Peak 95~C 95~C+10 ' Breakdown CG1~l.r O1 640 2770 3530 1690 1550 56 5 Jet-Cooked/S~ra~-Dried/Non-Granular T-I Waxy Maize - PH 8 Control 60 90 100 41 30 70 ~team Atomized/S~raY-Dried/Granular T-I Waxy Maize - ~H 8 Control 100 1010 1080 340 170 84 The results show that after 8 hours heat treatment at 140~C all the pregelatinized thermally-inhibited starches showed much less breakdown. The results also show that a higher degree of inhibition 15 along with a higher peak viscosity can be obtained if the starch granules are completely disrupted as by drum drying or jet cooking.

This example shows that a granular starch can 20 be dehydrated by ethanol extraction and that a better tasting starch is obt~; n~ .
A granular waxy maize starch was slurried in 1.5 parts water h~c~(~ on the weight of the starch and adjusted to PH 7 and 9. 5 with 5% sodium carbonate, held 25 for 30 minutes, filtered, and dried on a tray to a moisture content of about 5-6% moisture. The starch having the PH of 5.3 was a native starch which was not PH
- adjusted.
For the dehydration, the dried PH 5.3, PH 7.0, 30 and PH 9.5 starches were each separated into two samples.
One sample was dried on trays in a forced draft oven at CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 The thermally-inhibited starches were slurried at 6.6~ solids (anhydrous basis), pH adjusted to 6.0-6.5, and then cookeA out in a boiling water bath for 20 minutes. The resulting cooks were allowed to cool and then evaluated for viscosity, texture, and color.
Dehydration Time at Method 160~C Viscosity Texture Color Oven None heavy to cohesive sl. off-v. heavy white Ethanol None heavy to cohesive sl. off-v. heavy white 10 Oven5 hours mod. heavy non- sl. tan, to heavy cohesive, darker*
smooth Ethanol 5 hours mod. heavy non- sl. tan to heavy cohesive, smooth Oven 7 hours mod. heavy non- mod. tan, to heavy cohesive, darker*
smooth Ethanol7 hours mod. heavy non- mod. tan to heavy cohesive, smooth * Slightly darker than ethanol-dehydrated samples.
These Br~h~nA~r results show that highly inhibited starches can be obtained by both thermal and non-thermal dehydration. The cook evaluation results show that there is a benefit for the ethanol-dehydrated, thermally-inhibited starches in terms of re~l~c~A color.
As will be shown hereafter, there is also a flavor im~o~ement with ethanol dehydration.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 WaxY Maize (7~H 7.0) Dehydrated oven -- 1240 38069 T-I oven 7 hrs. 298 24020 T-I ethanol 7 hrs. 400 31023 Waxy Maize (pH 9.5) Dehydrated oven -- 1250 400 68 Dehydrated ethanol -- 1070 350 67 T-I ethanol 3 hrs. 665 635 5 T-I oven 3 hrs. 680 655 4 T-I oven 5 hrs. 245 460ris.
T-I ethanol 5 hrs. 160 375ris.
T-I Oven 7 hrs. 110 295ris.
T-I Ethanol 7 hrs. 110 299ris.
The results show that the starches can be dehydrated by ethanol extraction. The results also show that dehydration without the subsequent heat treatment did not inhibit the starch. The viscosity breakdown was not significantly different from that of the native waxy maize starch. Both of the thermally-inhibited pH 7 starches were higher in viscosity than the pH 5.3 (as is) thermally-inhibited starches. The starches which were thermally-inhibited at pH 9.5 were moderately highly inhibited or highly inhibited (rising curve).

GrAm7lAr tapioca, corn, and waxy rice starches and waxy rice flour were adjusted to pH 9.5, dehydrated - in an oven and by extraction with ethanol, and heat treated at 160~C for the indicated time. They were - evaluated for BrAhen~7Pr viscosity using the procedure previously described.

CA 022104~ 1997-07-24 wos6/23038 PCT/US96/00988 dehydrated and heat treated in an oven for the indicated time and temperature.
The peak gelatinization temperature and enthalpy (I~H) are shown below.
Peak Gelatinization Waxy Maize Temperature (~C) Enthalpy fcal/g) Unmodified 74 4.3 T--I 68 2.9 (pH 9.5;160~C
for 8.5 hrs.) T-I Waxy Naize 59 2.8 (pH 6;160~C
for 8 hrs.) X-linked 73 4.4 (0.0296 POC13) X--link~A 72 4.2 (o.049~ POC13) X-linked 74 4.2 (0.06% POC13) The results show that there was a significant reduction in peak gelatinization temperature of the thermally inhibited (T-I) starches. The heat treatment r~ ceA the enthalpy (~H) from 4.3 cal/g for the 25 unmodified starch to 2.8 - 2.9 cal/g for the thermally-inhibited starch. The chemically crossl; nk~f~ (X-linked) starches are essentially identical to the unmodified waxy starch in peak temperature (72-74~C vs. 74~C) and enthalpy (4.2-4.4 vs 4.3 cal/g). The reduced 30 gelatinization temperature and decrease in enthalpy suggest that the overall grAn~ r structure has been altered by the dehydration and heat treatment.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/OOg88 WaxY Rice Flour (PH 9.S and 160~C) Dehydrated oven -- 895 700 22 Dehydrated ethanol -- 870 410 53 T-I oven 5 hrs. 38 73 ris.
T-I ethanol 5 hrs. 140 260 ris.
T-I oven 7 hrs. 10 16 ris.
T-I ethanol 7 hrs. 40 100 ris.
The results show that pH 9.5-adjusted, ethanol-extracted, heat-treated tapioca and corn starches had viscosity profiles generally similar to those of the same thermally-inhibited starches which were oven-dehydrated.
The 7 hours heat-treated samples were more inhibited than the 5 hour heat-treated samples.

This example compares ethanol extracted granular waxy maize starches and oven-dehydrated granular waxy maize starches heat treated in an oven for 5 and 7 hours at 160~C at the same pH, i.e., pH 8.03.
The Brabender results are shown below.
ViscositY (BU) Dehydration/ Break-Heat Treatment Peak Peak + 10' down (%) Oven/None 1160 360 69 EtOH/None 1120 370 67 Oven/5 hrs. 510 455 11 EtOH/5 hrs. 490 445 9 Oven/7 hrs. 430 395 8 EtOH/7 hrs. 360 330 8 CA 022104~ 1997-07-24 -W096/23038 PCT~S96/00988 Dehydration/ Peak Heat Treatment Gelatinization Conditions TemperatureEnthalpy (cal/q) Control (pH 9.5) 74.82 4.05 127~C for 0 min. 74.84 4.17 160~C for 0 min. 73.04 4.50 160~C for 60 min. 71.84 4.60 160~C for 90 min. 70.86 4.26 Average of 2 readings.
The DSC results show that at the onset of inhibition there was a slight reduction in the peak gelatinization temperature and that as the inhibition temperature and time increased there was a reduction in peak gelatinization temperature. The enthalpy is llnckAnged or slightly higher, unlike the enthalpy of the more highly inhibited starches of the prior example.

This example shows the correlation between the RVA pasting temperature and time and DSC peak gelatinization temperature and time and the reduction in BrAh~n~er viscosity breakdown for various grAn~lAr starch bases and for gr~nl~lAr waxy maize starches dehydrated by various methods including heating, ethanol extraction, and freeze drying. The base starches were unmodified.
The starches were all adjusted to pH 9.5 before dehydration. The ethanol-extracted and freeze-dried ~Vll~ ols were pH adjusted and dehydrated but not heat treated. The dehydrated starches were all heat treated in an oven at 160~C for the indicated time except for the starches chemically crosslinked with sodium trimetAphosphate (STMP) which were heat treated at 160~C
for the indicated time in the fluidized bed previously described.

CA 022104~ 1997-07-24 W096/23038 PCr~S96/00988 A grAn~ r waxy maize starch was pH adjusted to pH 9.5 as previously described. The starch was then placed in a freeze dryer and dried for 3 days until it was anhydrous (0% moisture). The freeze-dried tFD) starch was heat treated for 6 and 8 hours at 160~C in a forced draft oven.
BrAhDn~er evaluations were run. The results are shown below:
Viscosity (BU) Waxy Maize Time at Break-(~H 9.5) 160~C ~ Peak + 10' down (%) Control -- 1260 320 75 F.D. - - 1240 320 74 T-I 6 hrs. 340 465 ris.
T-I 8 hrs. 285 325 ris.
The results show that the starch can be dehydrated by freeze drying and that the subsequent heat treatment is nPcDsc~ry to inhibit the starch. The starches are highly inhibited as shown by their rising viscosity.

This example shows that thermal inhibition reAllce~ the gelatinization temperature of the grA~ r 25 waxy maize starches.
The gelatinization temperature of an untreated waxy maize, a thermally-inhibited (T-I) waxy maize (pH
adjusted and not pH adjusted), and chemically-crosslinked (X-linke~) waxy maize starches (0. 02%, 0.04%, and 0.06%
phQSrhorus oxychloride) were determined by Differential Sc~nn ~ ~g Calorimetry. The starches were thermally CA 022104~ 1997-07-24 PCT~S96/00988 Dehydrated Thermally/Heat Treated at 160~C
T-I 68.15 3.7 70.71 6.6 760 720 5.26 (8 hrs.) Waxy 70.95 4.3 74.23 6.9 1250 400 68.00 Naize C~~ ol ~thanol DehYdrated/Heat Treated at 160~C
T-I 65.00 3.1 71.81 6.7 ris. ris. ris.
(2 hrs.) T-I 63.85 2.8 68.12 6.3 ris. ris. ris.
(7 hrs.) Waxy 71.30 4.4 74.16 6.9 1240 320 74.19 Maize CollL~ol Dehydrated by Freeze DrYinq/Heat Treated at 160~C
T-I 69.50 4.0 66.09 6.1 ris. ris. ris.
(6 hrs.) T-I 66.75 3.5 6~.64 6.0 ris. ris. ris.
(8 hrs.) Cross- 71.70 N.D. 74.33 6.9 ris. ris. ris.
1 ~ nk~rl Waxy Maize C~ ol CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 This example shows that the thermal inhibition may begin as early as 110~C (230~F), that it is substantially noticeable at 160~ (320~F), and that the gelatinization is ll~c-h~nged or reduced. Granular waxy maize starches were pH adjusted to 7.0 and 9.5 and dehydrated and heat treated using air having a Dew point below 9.4~C (15~F) in the fluidized bed previously described at the indicated temperature and time. The Brabender and DSC results are shown below.
Waxy Maize (pH 9.5) Dehydration/
Heat Treatment Conditions Brabender Viscosity (BU) Peak Peak + 10' Breakdown (9~) Control (pH 9.5)1240 300 75.8 93~C for 0 min. 1200 300 75.0 104~C for 0 min. 1205 320 73.4 110~C for 0 min. 1260 400 68.3 121~C for 0 min. 1230 430 65.0 127~C for 0 min. 1255 420 66.5 138~C for 0 min. 1245 465 62.7 149~C for o min. 1300 490 62.3 160~C for 0 min. 1120 910 18.8 160~C for 60 min. 750 730 2.7 - 160~C for 90 min. 690 680 1.4 CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 ViscositY (BU~
30~C 95~C Break-30OC +10' Peak 95~C +10' down (96) Crosslinked 150 165 215 120 70 67 Waxy Maize Control Crosslinked Waxy Maize Starch Cook Evaluation Viscosity 10Qf Cook Texture of Cook Crosslinked Waxy thin to moderate cohesive, pulpy Maize Control T-I Crosslinked very heavy non-cohesive, Waxy Maize very pulpy, short Starch The results show that after the dehydration and heat treatment steps the crossli~ke~ starch was very highly inhibited.

This example shows the thermal inhibition of converted starches.
Samples of waxy maize and tapioca starch were slurried in 1.5 parts water. The slurries were placed in a 52-C water bath, with agitation, and allowed to equilibrate for one hour. Concentrated hydrochloric acid (HCl) was A~e~ at 0.8% on the weight of the samples.
The samples were allowed to convert at 52~C for one hour.
The pH was then adjusted to 5.5 with sodium carbonate, then to pH 8.5 with sodium hydroxide. The samples were CA 022104~ 1997-07-24 -W096/23038 PCT~S96/00988 The results are shown below.
Starch Pastinq DSC Viscosity fB.U.~
Peak Peak Break TemP. Time Tem~. Time Peak +10' down (~C) (min) (~C) (min) (%) Tapioca 68.20 3.7 70.61 6.6 1595 440 72.41 Control DehYdrated ThermallY/Heat Treated at 160~C
T-I 66.65 3.4 68.31 6.3 123Q 560 54.47 (2 hrs.) T-I 64.20 2.9 65.41 6.0 355 335 5.63 (6 hrs.) Potato 61.05 2.3 62.67 5.8 1825 1010 44.66 Control Dehydrated Thermally/Heat Treated at 160~C
T-I 60.25 2.1 61.41 5.6 995 810 18.59 (3 hrs.) T-I 60.20 2.1 61.13 5.6 ris. ris. ris.
(6 hrs.) Waxy 70.95 4.3 73.86 6.9 1215 350 71.79 25 Maize Co~.L~Ql CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Waxy Maize (7% P0 and pH 9.5 at 160~C) Control -- 1420 395 -- -- 72 waxY Maize (3% P0 and natural pH at 160~C) Control -- 1155 280 -- -- 76 waxY Maize (3% P0 and pH 9.5 at 160~C) C~~ ~l -- 1155 280 -- -- 76 CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Thermally Dehydrated Crosslinked WaxY Maize*
T-I 69.10 N.D. 71.66 6.7 ris. ris. ris.
(30 5 min.) T-I 66.00 N.D. 67.14 6.2 ris. ris. ris.
( 150 min.) * Fluidized bed.
The results show that heat treatment of thermally and non-thermally dehydrated granular starches r~Allre~ the pasting and peak gelatinization temperatures while at the same time inhibiting the viscosity breakdown. Because the gelatinization temperature has been lowered by the heat treatment of the dehydrated starch, less time is required to reach the pasting and gelatinization temperatures. The more highly inhibited starches showed a lower pasting temperature and less breakdown in viscosity.

A grAm~lAr waxy maize starch which had been lightly crosslinked with 0.04% phosphorous oxychloride was thermally-inhibited. The granular starch was jet-cooked and spray-dried using the coupled continuous jet-coo~ing/spray-drying process and conditions described in Example 8. The spray-dried starch was oven dehydrated and heat treated for 8 hours at 140~C.
The Brabender results and viscosity and textural characteristics of the resulting thermally-inhibited starch are set out below.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Viscosity after 3280 -- -- 2640 24 hours (Cp8) Viscosity after 3020 2475 2730 2810 7 days (cps) Viscosity after 3000 1980 2140 2940 8 days (cps) Viscosity after 2850 1990 2230 2870 9 days (cps) Appearance clear clear clear yellow Waxy maize samples at the naturally occurring pH and at pH 8.5, were reacted with 1% by weight acetic anhydride (Ac20) and thermally-inhibited. The control was the non-thermally-inhibited waxy maize starch acetate.
The results are shown below.
ViscositY fBU) Break-Time Peak + 92-C + down (min) Peak lo~ 92-C 30' (%) Waxy Maize t1% Ac20 and natural pH at 160~C) Control -- 1480 490 -- -- 67 Waxy Maize (1% Ac2O and natural pH at 160~C) CollLrol -- 1480 490 -- -- 87 CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 recovered by filtering and air drying (approximately 11%
moi~ture). The starches in 50g amounts were placed in an aluminum tray, covered and placed into a forced draft oven at 140~C for 5.5 hours. The starches were evaluated for inhibition.
The results set out in the following table.
WaxY Maize TaPioca ViscositY (BU) VisCositY (BU) Peak Break- Peak Break-Peak + 10' down Peak + 10' down (%) (%) unmodified 1380 250 81.9 810 225 72.2 acid 640 110 82.3 432 115 73.4 converted T-I acid 805 728 9.6 495 350 29.3 converted The results show that converted starches can be thermally inhibited by this process.

Waxy maize samples reacted with 7% and at 3% by weight propylene oxide (P0), at the naturally occurring pH and at pH 9.5, were evaluated for inhibtion.
The results set out in the following tables.
Viscosity fBU) TemP Time Peak Peak + 92~C 920C + Breakdown (~C) (min) 10' 30' (%) Waxy Maize (7% P0 and natural ~H at 160~C) CollLrol -- 1420 395 -- -- 72 CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 The starches were adjusted to pH 9.5 and heat treated at 100~C, 110~C, 120~C, 130~C and 140~C for 0 minutes using the fluidized bed previously described.

This example shows the use of thermally-inhibited converted acetylated waxy maize starch as an adhesive for bonding kraft paper.
A waxy maize starch converted to a water fluidity of 75-85 and derivatized with 3% acetic anhydride was adjusted to pH 9.5, and thermally-inhibited using the fluidized bed reactor as previously described.
Samples were taken at 110~C, 130~C, 150~C, and after 90 minutes at 160~C.
Pre~aration Of The Adhesive The starch samples were cooked at the indicated solids in tap water at 88-93~C (190-200~F) bath temperature for 30 minutes to yield a final solution having a Brookfield viscosity of approximately 1200-1500 cps, which is typical of a st~nA~rd commercial starch cook. The % solids were recorded using a st~nA~rd optical refractometer.
The viscosity stability at room temperature of the starch cooks was evaluated. ~Ah~cion properties were examined by drawing down a wet film of adhesive using a 3.0 mil bird applicator on kraft paper, followed by mating with a c~co~A sheet of kraft paper. This bond was then moderately compressed with a hand roller and allowed to dry overnight. Percent fiber tear following a slow hand pull of the dried bond was evaluated, with 100%
indicating a completely destructive bond. The collLrol was the converted acetylated starch which was not thermally inhibited.
The results are tabulated below:

CA 022104~ 1997-07-24 W096/23038 PCT/U~5 160 0 1220 960 ~ 21 160 90 -- -- 750 790 ris.
160 120 -- -- 620 780 ris.
160 150 -- -- 510 750 ris.
160 180 -- -- 400 700 ris.
The data show that derivatized starches, in this case etherified starches, can be thermally inhibited lo by this process and that higher inhibition can be achieved at higher pH.

A converted hydroxypropylated waxy maize starch (25 WF starch reacted with 2% propylene oxide) was adjusted to pH 9.5 and thermally inhibited using the fluidized bed previously described. Samples were taken at 110~C, 125~C, and 140~C, all for 0 minutes.
The thermally-inhibited starch samples were cooked in tap water at 88-93 C (190-200-F) bath temperature for 30-60 minutes to yield solutions having a Brookfield viscosity of approximately 3000 cps. The viscosity stability at room temperature was evaluated.
The collL~ol was a hydroxy-propylated waxy maize starch which was not thermally-inhibited.
The results are tabulated below.
Solution Stability CollLrol 110~C 125~C 140~C
Water Fluidity 25.0 25.5 20.6 21.8 Solids (%) 18 18 18 18 Initial 3160 2550 2820 2800 Viscosity (cps) CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 As shown above, the thermal inhibition process ~enA~ to impart a slight im~lu~ement in overall stability of the solution viscosity versus the control.
The more thermally-inhibited starch showed an unusually high level of stability. Under these test conditions, the thermal inhibition did not provide either increased or decreased adhesion characteristics.

This example shows the use of a thermally-inhibited, acid converted, hydroxypropylated waxy maize starch as cigarette-making adhesives in the three bo~;ng applications, i.e., cigarette paper to itself for the side seam, tipping paper to itself, and tipping paper to cigarette paper to mimic the tipping bonds.
The acid converted, hydroxy~opylated waxy maize (25 WF starch reacted with 2% propylene oxide) was adjusted to pH 9.5 and thermally inhibited using the fluidized bed previously described. Samples were taken at 110~C, 125~C, and 140~C.
The thermally-inhibited starch samples were CoO~A in tap water at 88-93~C (190-200~F) bath temperature for 30-60 minutes to yield solutions having a Brookfield viscosity of approximately 3000 cps. The viscosity stability at room temperature and adhesion characteristics were evaluated. The control was the acid-converted, hydlop~oplated starch which was not thermallly inhibited.
The results are tAhlllAted below.

CA 022104~ 1997-07-24 W096/23038 PCr/US96/00988 875 600 ~~ ~~ 31 The data show that derivatized starches, in this case esterified starches, can be inhibited to varying degrees and that higher inhibition can be obtA;neA at higher pH.

This example shows the preparation of potato starches modified with an amino-multicarboxylic acid (CEPA) reagent, i.e., 2-chloroethylaminodipropionic acid and their subsequent thermal-inhibition.
Overhead stirring was used throughout this reaction. Deionized water (150 ml) was added to a liter heAker and heated to 45~C with an external constant temperature bath. A total of 30 g sodium sulfate (30% on starch) was dissolved in the water followed by the 20 addition of 100 g of the potato starch. A solution of 3%
aqueous sodium hydroxide (25 ml) was added slowly with good agitation to minimize starch swelling. A 25%
aqueous solution of the CEPA reagent ( 32 ml) to give an 8% starch treatment (dry basis) was added simultaneously with a 3% aqueous sodium hydroxide solution (170 ml).
The addition rates used kept the level of caustic high so that pH was about 11.0 to 11.5 during the reaction. The reaction was run at 42-45 C for 16 hours and then neutralized by adding 3 N hydrochloric acid to adjust pH
30 to about 6. 5, followed by stirring for 30 minutes. The starch was then filtered and washed twice with 150 ml of water and allowed to air dry. Analysis of the starch for bound nitrogen showed 0. 25% N (dry basis).

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Tear Of Samples Bond A B C D E
cig-cig lOO lOO lO0 lOO lOO
cig-tip lOO lOO lO0 lOO lOO
5 tip-tip lOO lOO lOO lOO lOO
Since the adhesion characteristics of the above samples were achieved at significantly lower solids contents than a commercial starch material (18% vs. 45%), studies were carried out comparing the non-thermally-inhibited base starch and Sample D at various solids contents. The results are shown below:
The percent fiber tear (FT) following a slow hand pull of the dried bond was evaluated, with 100%
indicating a completely destructive bond.
Film Tear Bond Control Sam~le D
140~C for O minutes Cig-cig 15% solids 100% FT 100% FT
10% solids 100% FT 100% FT
205% solids O~ FT 25% FT
Tip-tip 15% solids 100% FT 100% FT
10% solids 100% FT 100% FT
S% solids 15% FT 15% FT
Cig-tip 15% solids 100% FT 100% FT
10% solids 100% FT 100% FT

CA 022104~ 1997-07-24 W096l23038 PCT~S96/00988 110~C 130~C 150~C 160~C
for for for for Control 0 min 0 min 0 min 90 min Water 71.4 73.7 73.5 74.3 73.7 Fluidity Solids (%) 17 18 18 18 18 Initial 1300 1460 1490 1350 1320 Viscosity (cps) Viscosity 1710 1840 1620 1880 1430 after 24 hours (cps) Viscosity 3160 3020 2820 2670 1810 after 6 days (cps) Viscosity 3050 3270 2940 2750 1710 after 7 days (cps) Viscosity 3390 3460 3160 2910 1760 after 8 days (cps) Overall 161 137 112 116 33 Viscosity Change (%) ~hP~ion 100% 100% 100% 100% 100 (film - tear) Appearance white white white gray gray-brown CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Xathon LX1.5 0.15 0.15 Petroleum-based defoamer 0.20 0.20 Methyl salicylate o.og o.og The first five ingredients were mixed for 15 minutes, the dextrin-emulsified ethylene vinyl acetate and amioca dextrin were added, and mixture was stirred for 30 minutes at 180-190~F. The rema;n;~g ingredients were added and mixed in while cooling.
After dilution with 21 mls of water, the ~ol.LLol adhesive (69.2% solids) had a Brookfield viscosity of >50,000 cps at 27~C (75~F) whereas the adhesive cont~;n;ng the thermally-inhibited starch (68.0%
solids) had a viscosity of 48,050 cps at 22~C (75~F).
After dilution with an additional 11 mls of water, the respective viscosities were 24,550 cps (~unLLol) and 22,200 cps (T-I starch). The check chill viscosity after aging overnight was 25,200 cps for the col.LLol and 21,800 cps for the T-I starch.
An evaluation of "cottoning" was done on each sample. The results were comparable.

This example shows the use of blends of thermally-inhibited corn starch and thermally-inhibited high amylose corn starch (70% amylose) as the carrier starches of corrugating adhesives.
The adhesives were formulated as follows:
Primary Tank ~l ~2 ~3 ~4 Cook water 2335 g 2335 g 2335 g 2335 g T-I Corn/T-I High 560 g -- -- --30 Amylose Blend (60/40) (pH 9.5;
160~C for 60 min) -CA 022104~ 1997-07-24 W096/23038 PCT~S96tO0988 Solution StabilitY
A B C D
110~C 125~C 140~C
for for for Co~ ol O min O min O min Water 25.0 25.5 20.6 21.8 Fluidity Solids (%) 18 18 18 18 Initial 3160 2550 2820 2800 Viscosity (Cp8) Viscosity 3280 -- -- 2640 after 24 hours (Cp8) Viscosity 3020 2475 2730 2810 after 7 days (cps) Viscosity 3000 1980 2140 2940 after 8 days (cps) Viscosity 2850 1990 2230 2870 after 9 days (cps) Appearanceclear clear clear yellow The percent fiber tear following a slow hand pull of the dried bond was evaluated, with 100%
indicating a completely destructive bond.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 quench water was added and mixing was continued for 5 minutes.
The mixture from the primary tank was added to the contents of the secondary tank at medium speed (860 rpm) over a 20-30 minute period. After the addition was completed, the mixer speed was increased to high (1450 rpm) and mixing was continued for 60 minutes.
With the adhesive at 100~F, the Stein-Hall and Brookfield viscosity r~A~ings were taken after 0, 30, and 60 minute high speed mixing. The results are shown below:
Adhesive Viscosities Brookfield Brookfield Carrier Stein Hall Viscosity Viscosity Starch Viscosity 20 rpm 100 rpm (sec) (cps) (cps) Control - 26 224 228 Unmodified Starch Blend Crosslinked 33 286 273 Starch*
T-I Starch 24 2375 784 Blend (pH
9.5; 160~C
for 60 min) T-I Starch 19 1580 502 Blend (pH
9.5; 160~C
for 180 min) * Comparative Doubleback samples were prepared for adhesive testing.

CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 5% solids 0% FT 10% FT
As indicated by the above results, thermal inhibition appears to impart enhanced adhesion. No increase or decrease in solution viscosity stability was noted.

This example shows the use of a thermally-inhibited (T-I) waxy maize starch in an envelope adhesive. A lightly crosslinked starch was used as the 10 C;~ll~Ol.
The waxy maize was adjusted to pH 9.5 and thermally inhibited at 160~C for 180 minutes using the fluidized bed as previously described.
The ingredients are listed below.
T-I Waxy Maize Ingredients Control Water 40-00 40-00 Petroleum-h~ce~ defoamer 0.30 0.80 Dextrin-emulsified vinyl acetate homopolymer 18.29 18.29 Crosslinked amioca 0.80 --T-I Waxy maize -- 0.80 Dextrin-emulsified 18.29 18.29 polyvinyl acetate Waxy maize dextrin 46.96 46.96 Propylene glycol 1.98 1.98 Polyethylene glycol 2.96 2.96 (Carbowax 600) Dioctyl sulfosuccinate 0.10 0.10 CA 022104~ 1997-07-24 Wos6/23o38 PCT~S96/00988 T-I Starch 174 7 100 Blend (pH
9.5; 160~C
for 60 min) T-I Starch 182 6 100 Blend (pH
9.5; 160~C
for 180 min) ~ Average of 16 runs.
The results show that the thermally-inhibited starches can be used as carrier starches in a typical corrugating adhesive, giving bond strengths (as measured by doubleback evaluations) and Stein Hall viscosities comparable to unmodified or chemically crossl;nke~
carrier starches. The viscosity of adhesives prepared with the thermally-inhibited starches as the carrier starch also poscecsed unique viscosity behavior. The adhesives prepared using the thermally-inhibited starches as the carriers had much higher Brookfield viscosities than the chemically crossl;nke~ or the untreated starches.

This example describes the preparation of a natural-b~ce~, lay-flat laminating adhesive. Adhesives A
and B are formulated as follows:
Parts Tn~redients - B
Water 60 60 Unmodified waxy maize starch 5 --T-I corn starch (pH 9.5; 160~C -- 5 for 90 minutes) CA 022104~ 1997-07-24 W096l23038 PCT~S96100988 T-I Corn/T-I High -- 560 g -- --Amylose Blend (60/40) (pH 9.5;
160~C for 180 5 min) Unmodified -- -- 560 g --Corn/High Amylose Blend (Col.L~ol) Crosslinked -- -- -- 560 g Corn/High Amylose Blend (0.005%
epichlorohydrin)*
Sodium Hydroxide 101 g 101 g 101 g 101 g Water (for 234 g 234 g 234 g 234 g dilution of NaOH
Borax (5 mole) 17 g 17 g 17 g 17 g Quench water 75~F 2335 g 2335 g 2335 g 2335 g Secondary Tank Water (95~F) 7006 g 7006 g 7006 g 7006 g Unmodified raw 3640 g 3640 g 3640 g 3640 g corn starch Borax (5 mole) 67 g 67 g 67 g 67 g * Comparative The moisture of the carrier starches and the raw starch was 10% and the water was adjusted accordingly.
The water and the carrier starch were heated to 130~F. The sodium hydroxide and the dilution water were mixed. Mi Yi ~g was continued for 10 minutes. The borax was added and mixing was cont;m~e~ for 20 minutes. The CA 022104~ 1997-07-24 W096/23038 PCT~Ss6/00988 T-I Converted Tapioca Starch (35 WF; 30.0 pH 9.5; 160~C for 120 minutes) Urea 12.0 Aluminum Sulfate (Crosslinker) 1.0 Ethylene-Vinyl Acetate Resin 15.0 Preservative 0.1 The starch is slurried in water and heated to (190~F). During the heating the urea is added all at once. The slurry is cooked at 88~C (190~F) for 20 minutes and cooled to 57~C (135~F). The crosslinker, pre~;~colved in 10% water (based on the 400 g. sample), is slowly added and mixed thoroughly for 10-15 minutes.
The resin is slowly added and mixed thoroughly for 10-15 minuts. The preservative is added and mixed thoroughly for 5-10 minutes. The mixture is cooled to 22~C (72~F) and the pH, % solids, and initial viscosity are measured.
The pH should be 7-8; the solids should be 40-45%; and the initial viscosity should be 50,000-60,000 cps.
It is expected that this adhesive will have better tack, good rheological properties such as good flowability, and good adhesion. In addition, the elimination of c~ein lowers the formulating cost.

This example describes the preparation of a ceramic tile cement.
The following dry ingredients are blended together:
Tnqredient Parts Type 1 Portland Cement 350 Silica sand (F 65 grade) 620 Lime (Type 5), Calcium Hydroxide 25 CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 Using the freshly prepared adhesive, a small guantity (approximately 50 grams) of the adhesive was poured on glass drawdown plate. Using a 6" x 10" bird applicator, an adhesive drawdown was made by pulling the applicator towards ones~lf to create an adhesive film. A
6" x lO" singleface web was placed over the adhesive drawdown and pressed down uniformly in order to wet the flute tips. A 6" x 12" liner was placed on a hot plate preset at 350~F and the wetted singleface web was quickly transferred onto the liner, covered with a weighted lid, held for five (5) s~conA~, and removed immediately. The finished board samples were placed in a 72~F/50~ relative humidity room to equilibrate for a period of at least 24 hours. For testing, the board was cut in the following manner: (a) first, the excess liner was cut off from both ends of the prepared boards; (b) a 1" x lO" strip of doubleback board was cut off using a specially designed cutter and ~;cc~rded; (c) from the remaining board, two 2" x lO" board samples were cut; and (d) each 2" x lO"
~trip was cut in half.
The 2" by 5" strips were tested for dry pin strength using an a~o~iate H&D tester.
The adhesive results are shown below:
Adhesive Bond Strength - Doubleback DrY Pins Carrier Starch Averaqe flbs.~ Std. Dev. Fiber Tear (%~
CollL~ol - 179 9 lOO
Unmodified Starch Blend Comparative- 183 6 lOO
Crossl;nke~
Starch Blend CA 022104~ 1997-07-24 W096l23038 ~CT~S96/OOg88 T-I converted waxy maize (85 -- 10 WF; pH 9.5; 160~C for 180 minutes) Corn syrup (humectant) 30 30 Sodium Nitrate 18 18 Urea 12 12 It is expected that the resulting adhesives will have better viscosity stability because of the thermal inhibition and better adhesion because of the higher starch solids which can be used since the viscosity of the adhesive will be stable.

This example describes the preparation of an adhesive suitable for use in tissue ply-bonding for the manufacturing of towels and disposables.
The adhesive is formulated as follows:
TnqredientS Parts Water 80 T-I Hydroxypropylated Waxy Maize 20 (8% ~u~lene oxide; pH 9.5; 160~C
for 180 min.) It is expected that the viscosity stability and adhesion will be im~Lo~ed.

This example describes the preparation of a typical bottle labeling adhesive.
The adhesive formulation (400 g) contains the following ingredients:
Tn~redient %
Water 41.9 CA 022104~ 1997-07-24 W096/23038 PCT~S96/00988 High viscosity hydroxypropylated 2.5 methylcellulose (Dow K15 M) T-I Pregelatinized GrA~ r Waxy Maize 2.5 Starch (pH 9.5; 160~C for 0 minutes) A total of 225 parts of water are added to the blended dry ingredients and mixed until smooth. The adhesive should have a Brookfield heliopath viscosity of 225,000 cps (TF spindle, 10 rpm).
The advantages of this formulation should be improved workability and lowered trowelling cost.
Now that the preferred emhoAimentS of the present invention have been described in detail, various modifications and improvements thereto will become readily apparent to those skilled in the art.
Accordingly, the spirit and scope of the invention are to be limited only by the app~n~e~ claims and foregoing specification.

CA 022104~ 1997-07-24

Claims (20)

WHAT IS CLAIMED:

1. An adhesive which comprises an aqueous carrier containing an effective amount of a solubilized thermally-inhibited starch or flour, which starch or flour is prepared by (a) dehydrating a starch or flour to a moisture content of less than 1% to render the starch or flour anhydrous or substantially anhydrous, and (b) heat treating the anhydrous or substantially anhydrous starch or flour for a time and at a temperature sufficient to inhibit the starch or flour, which temperature is 100°C or greater and which time is up to 20 hours, characterized in that the thermally-inhibited starch or flour, after dispersion in water, has improved viscosity stability in comparison to a dispersion of the non-thermally-inhibited base starch or flour in water.

2. The adhesive of Claim 1, wherein the starch or flour is a cereal starch or flour, a tuber starch or flour, a root starch or flour, a legume starch or flour, or a fruit starch or flour; wherein the starch or flour is adjusted to a pH of neutral or greater prior to the dehydrating stop; and wherein the thermally-inhibited starch or flour is a non-pregelatinized thermally-inhibited granular starch or flour which has an unchanged or reduced gelatinization temperature.

3. The adhesive of Claim 1, wherein the starch or flour is a cereal starch or flour, a tuber starch or flour, a root starch or flour, a legume starch or flour, or a fruit starch or flour; wherein the starch or flour is adjusted to a pH of neutral or greater prior to the dehydrating stop; and wherein the thermally-inhibited starch or flour is a pregelatinized granular or non-granular thermally-inhibited starch or flour.

4. The adhesive of Claims 2 or 3, wherein the dehydration is a thermal dehydration; wherein the pH is 7 to 10; wherein the heat treating temperature is 120 to 180°C; and wherein the heating time is 2 to 5 hours.

5. The adhesive of Claim 4, wherein the pH is above 8 to below 10, the heating temperature is 140-160°C, and the heating time is 0.5 to 3 hours.

6. The adhesive of Claim 1, wherein the dehydrating and heat treating steps simultaneously in a fluidized bed.

7. The adhesive of Claim 6, wherein the thermally-inhibited starch of flour is selected from the group consisting of corn, pea, oat, potato, sweet potato, banana, barley, wheat, rice, sago, amaranth, tapioca, sorghum, waxy maize, waxy tapioca, waxy rice, waxy barley, waxy potato, waxy sorghum, and a starch or flour having an amylose content of 40% or greater.

8. The adhesive of Claim 1, wherein the thermally-inhibited starch is corn, potato, rice, oat, waxy maize, waxy tapioca, waxy rice, waxy barley, or waxy potato and wherein the thermally-inhibited flour is tapioca flour.

9. The adhesive of Claim 1, wherein the thermally-inhibited starch is a highly inhibited starch prevent in an amount of about 1-20% by weight or a lightly inhibited starch present in an amount or about 1-40% by weight, based the weight or the adhesive composition.

10. The adhesive of Claim 9, wherein the highly inhibited starch is about 2-5% and the lightly inhibited starch is about 10-20%.

11 The adhesive of Claim 1, wherein the adhesive is a liquid or paste adhesive prepared by cooking the thermally-inhibited starch or flour in water.

12, The adhesive of Claim 1, wherein the adhesive is a corrugating adhesive which comprises water, an alkali, a gelatinized thermally-inhibited carrier starch, and an ungelatinized starch or corrugating adhesive which comprises water, an alkali, a gelatinized carrier starch, and an ungelatinized thermally-inhibited starch.

13. The adhesive or Claim 12, wherein the thermally-inhibited gelatinized carrier starch is selected from the group consisting of corn, high amylose corn, potato, wheat and mixtures thereof.

14. The adhesive of Claim 13, wherein the thermally-inhibited gelatinized carrier starch is a mixture of corn starch and high amylose corn starch.

15. The adhesive of Claim 1, which is a remoistenable adhesive comprising an aqueous emulsion of an ethylene-vinyl acetate polymer, an emulsifier or a protective colloid, a dextrin, and the thermally-inhibited starch.

16. The adhesive of Claim 1, which is used for bonding cigarette paper.

17. The adhesive of Claim 1, which is used for bonding bottle labels to glass or plastic bottles.

18. The adhesive of Claim 1, which is used as a laminating adhesive.

19. The adhesive of Claim 1, which is used as a tube-winding adhesive or as a ply bonding adhesive for disposables.

20. The adhesive of Claim 1, which is used as a ceramic tile cement.