US 2601597 A
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Patented June 24, 1952 APPLICATION OF DISPERSED COATING MATERIALS TO CELLULOSIC FIBERS John H. Daniel, J r., Stamford, Lucius H. Wilson,
Greenwich, Randall Hastings, Stamford, and
Chester G. Landes, New Canaan, Conn., as-
; signors to American 'Cyanamid Company, New 3. York, N. Y., a corporation of Maine No Drawing. Application September 6, 1946, Serial No. 695,292
7 Claims. 1
This invention relates to the application of coating or impregnating materials to fibrous cellulosic material, to coated or impregnated cellulosicfibers obtained thereby, and to the manufacture of other articles from the coated or impregnated fibers. More particularly, the invention relates to the incorporation of dispersions or emulsions of water-insoluble coating or impregnating materials such as resins, precipitated or insoluble sizes, elastomers, waxes, pitches, bitumens, oils, etc. into fibrous cellulosic material such as paper stock, cotton, and the like followed if desired by forming the resulting pretreated cellulosic material into fibrous felted sheets or articles such as paper, paper board, moulded or premculded cellulosic articles and the like. The invention includes processes for the manufacture of new types of paper, paper board, pulp and pulp preiorms as well as a wide variety of novel products obtained therefrom, either directly or by subsequent treatments such as shredding, impregnating, cold pressing, hot pressing, heating, calendering, hot calendering and the like. I
Heretofore the principal methods of incorporating resins, waxes, waterproofing and greaseproofing agents, binding agents and the like into a sheet of pulp or paper have been by impregnation of-the formed sheet or object by a water solution, organic solvent solution or dispersion of the material to be incorporated or by addition of the impregnating agent to the pulp-Water slurry, called slush stock or paper stock, either as a substantially Water-insoluble dry powdered material or as a precipitate from a water solution, solvent solution, or dispersion or emulsion of the impregnating material. Thus, for example, it is common practice to add fillers such as clay and sizing materials such'as rosin soap, rosin or wax emulsions or dispersions, latices, asphalt emulsions, and the like to slush stock in the beater, stock chest or at any other point in the stock system prior to sheet formation, preceded or follower by the addition of alum. By this procedure the sizing materials are precipitated and the resulting fiocs are entangled or mixed with the fibrous paper stock and 'are carried into the finished paper.
This procedure works fairly well in those cases where only small amounts of certain materials are added to the paper, such as amounts on the order of 0.5-5 on the weight of the fiber. However, serious operating difficulties are frequently encountered when attemptsare made to incorporate larger quantities of impregnating agents by these methods. Some or all of the following difiiculties are frequently encountered.
1. The resinous material is agglomerated in balls or lumps instead of forming flocs of small particle size. This may cause the sheet to stick to the presses, driers, felts and calenders when the impregnated pulp is run out on a papermaking machine.
2. Coverage of the individual fibers may be poor.
3. Distribution of the resin in the sheet may be non-uniform, resulting in a mottled appearance of the sheet and causing non-uniform ink reception.
4. Sheet formation is often harmed.
5'. Precipitation of the resin is frequently incomplete, and much of the resinous impregnating material is lost in the white water.
6. Agglomerates of the resin, together with unprecipitated resin, tend to deposit as sticky aggregates in pipe lines, tanks, and various other portions of the papermaking equipment.
Some Of these difficulties, such as the appearance of rosin spots and lumps of agglomerated material are frequently encountered in paper mills even when amounts as small as O.253% of certain types of rosin and wax emulsions are added.
The present invention has as a principal object an improved method for the incorporation of impregnating agents into fibrous cellulosic material in such a manner that many of the difficulties enumerated above are avoided. In accordance with preferred embodiments of the invention, this is accomplished by obtaining a more uniform and complete coating or impregnation of the cellulosic fibers with the impregnating agent prior to the felting or forming step. A second important object is to provide a process for the incorporation of a wide varietyof impregnating agents into or upon fibrous cellulosic material in such a manner that these added materials do not seriously interfere with the normal method of production of paper pulp sheets, pulp preforms and the like on standard papermaking equipment, even when large quantities of impregnating materials are used. A further object is to eliminate many of the difiiculties ordinarily encountered in the coagulation of resinous dispersions by inorganic precipitating agents such as alum, including difiiculties arising through non-uniform coverage of the pulp fibers, formationof sticky aggregates of the precipitated material, and extremely slow drainage of water from agglomerated resin-fiber masses on the sheetforming wire or screen.
Further objects of the invention involve the formation, on standard papermaking or pulpforming or preforming equipment, of easily handled sheets, boards and preforms containing new combinations of fibers, or fibers and fillers, with certain special resinous impregnating agents that have not heretofore been incorporated successfully by slush stock treatment. Thus, for example, certain special thermosetting resins or condensates such as urea-formaldehyde resins, phenol-formaldehyde resins, alkyd resins and the like may be incorporated into paper stock in the quantities necessary for premoulding and moulding processes. Similarly, a wide variety of thermoplastic resins, elastomers and the like may be incorporated in the large quantities necessary for laminating and moulding processes.
A wide variety of organic binders, sizing agents, oils, waxes, pitches, gums and natural resins may also be incorporated. Various combinations of any two or more of these resins may likewise be incorporated if desired. By applying the principles of this invention, resin-impregnated paper or paper board having superior properties can be prepared, as well as new types of products made from the treated paper or pulp by such conventional operations as laminating, moulding, pressing, calendering, extruding and the like. Instead of forming the treated pulps or fibers, they can be shredded, chopped or ground to produce new types of insulating agents, moulding powders, fillers for standard moulding or casting resins, and the like.
The present invention is based on the discovery of an unusual type of flocculation and deposition that is brought about by the action of cationic alkylenepolyamine-halohydrin resins in an aqueous system containing fibrous cellulosic material of the type of paper pulp suspended therein together with an aqueous dispersion of water-insoluble coating or impregnating agents. It has been found that in such a system the cationic alkylenepolyamine-halohydrin resin causes a controlled flocculation such that particles of the impregnating agent are uniformly coated upon or impregnated into the cellulose fibers. When dispersed or defiocculated water-insoluble impregnating or coating agents are applied in this manner the cellulosic fibers retain their property offe'lting or forming into shaped or sheeted articles despite the presence of large quantities of the impregnating agent, which in some cases may even be greater than the weight of the cellulosic fibers themselves. Moreover, when the proper quanti ties of cationic alkylenepolyamine-halohydrin resin are applied in the manner hereinafter described a high degree of retention of the flocculated material by the cellulosic fibers is obtained, and losses of organic material in the white water system are largely avoided.
The process of the invention therefore comprises as an essential feature the flocculation of an aqueous dispersion of an impregnating agent in the presence of fibrous cellulosic material suspended in the aqueous medium by the action of a cationic alkylenepolyamine-halohydrin resin. The distinctive type of flocculation that is ob-' tained when an aqueous solution of this type ofresin is added to an aqueous dispersion such, for example, as an emulsion-polymerized polystyrene dispersion will be described and illustrated hereinafter in greater detail. The invention in its broader aspects includes any process wherein this" flocculating action is used for the deposition or incorporation of an impregnating agent into flbrous cellulosic material.
In addtion to the foregoing, one of the most important features of the invention is the discovery that the distinctive flocculating action of the cationic alkylenepolyaminehalohydrin resin continues, and is in many cases actually ening the felting properties of the fibers, so that after impregnation they can still be felted together and formed into sheeted or moulded products by conventional wet-moulding or papermak ing procedures.v
Although the invention is not dependent on any particular theory of operation, the following is offered as themost probable explanation of the unusual type ofiluocculation and retention that is obtained. As is noted above, definite quanti ties of the cationic polyamine-halohydrin resin are adsorbed upon and retained by the cellulosic fibers when the cationic resin solution is added to an aqueous-suspension thereof. As a result of this treatment. the fiber-resin entity becomes positively charged, as contrasted with the nega-' tive charge usually associated with cellulose fibers. The resulting positively charged, resintreatedfibers in aqueous suspension exert an appreciable flocculating action on emulsions or dis-' persions of water-insoluble organic materials. and this is particularly evident when the emulsified or dispersed impregnating material carries a negative charge as when an anionic dispersing agent is employed in its preparation. The result is that after addition of the emulsion or dispersion ofthe impregnating agent to the aqueous suspension ofresin-treated cellulosic pulp, the dis'- persed particles are attracted to and flocculated on the positively charged fibers forming a layer or coating upon and around the fibers and per mitting the formation of a mat of the coated fibers on a screen or paper machine wire, with substantial retention of both the fibers and the coagulated particles of the non-fibrous disper-" sion'.
When the aqueous suspension of cellulosic material is pretreated with acontrolled excess of the cationic polyamine-halohydrin resin, over and above that required to impart a positive charge on the cellulosic fibers, the iinad'sorbed positively charged polyamine-halohydrin resin also possesses a strong fio'cculating action. Therefore when an emulsion or dispersion of an organic impregnating agent is added, two simul+ taneous flocculating' actions occur. 4 Part of the dispersednon-fibrous particles of impregnating agent are attracted to and deposited on the positively" charged fibers, forming a substantially uniform coating over the entire fiber surface. Simultaneously, the remainder of the emulsified or dispersed particles are coagulated into small floc's or agglomerates containing in intimate admixture the poly'amine-"halohydrin resin and particles of the added emulsion or dispersion. These fiocs or aggregates of combined resins, by reasons of their finely divided condition. readily coat or entangle with the fibrous portion of the mixture and offer little resistance to the drainage of the water during felting and forming of a sheet or mass of the pulp on a screen'or wire. As a result of these combined fiocculations it is possible, by proper control of the amount of added polyamine-halohydrin resin and other factors, to obtain complete or nearly complete retention of both the cationic resin and almost any desired proportion of organic impregnating agents.
Although the foregoing is regarded as the most probable explanation of the phenomena involved, the process of the invention is not necessarily limited thereto. On the contrary, it is possible that other factors may play an important part in the flocculation of the dispersed impregnating agents. Thus, for example, both the cellulose fibers and the alkylenepolyamine-halohydrin resin attached thereto, as well as the excess poly-.
amine resin remaining in aqueous suspension, undoubtedly present enormous surfaces upon which the molecules of various emulsifying agents can be adsorbed from water solution. It is therefore quite possible that the polyamine resincoated fibers, as well as the polyamine-halohydrin resin itself, may adsorb appreciable quantities' of emulsifying or emulsion-stabilizing agents associated with a third component added to the system, and thereby contribute to the flocculation of the particles of the third component and their agglomeration on the fibers. This mechanism may explain why materials dispersed by means of non-ionic or in some cases even by cationic dispersing or emulsifying agents are often retained with cellulose fibers by means of the cationic alkylenepolyamine halohydrin resin solution.
' The flocculating agents used in practicing our invention, and which are designated for convenience'as polyamine-halohydrin resins are reaction products of polyamines with polyfunctional halohydrins such as a dihalohydrin, e. g. alpha-dichlorhydrin, dibromhydrin or di-iodhydrin or any of the corresponding monohalohydrins containing a second radical or group capable of reacting or promoting reaction with a'polyamine such as epichlorhydrin, epibromhydrin, epi-iodhydrin, di-epi-iodhydrin and the like. Although arylenediamines such as p-phenylenediamine may be used in preparing these the halohydrin is believed to take place in two stages, the first being a simple linear condensation and the second a polymerization or selfalkylation reaction. We have found, however, that resinous products suitable for use as flocculating agents in the process of the present invention are obtained without the necessity of obtaining a thermosetting resin by this reaction. Thus, for example, excellent results are obtained with condensation products of equimolecular quantities of polyalkylenepolyamines such as diethylenetriamine, triethylenetetramine and tetraethylenepentamine and epichlorhydrin or di-,
chlorhydrin, even though the condensation at this molecular ratio yields resins which are not thermosetting. On the other hand, the condensation product of two mols of epichlorhydrin or dichlorhydrin with one mol of a polyalkylenepolyamine such as tetraethylenepentamine is thermosetting in character, and can be used where a thermosetting resin is desired. Larger proportions of the halohydrin can be and frequently are employed Where a thermosetting resin having a greater speed of cure is desired, the optimum being between about 2:1 and 3:1. When more than four mols of the polyfunctional halohydrin are used for each mol of tetraethylenepentamine or similar polyalkylenepolyamine the resin is thermosetting but the syrups are less stable in character and must be manufactured and stored at concentrations of less than 10% to avoid premature gelation.
The cationic polyamine resins used in practicing the present invention are therefore prepared by reacting one mol of a polyamine, and preferably an alkylenepolyamine such as ethylenediamine or a polyalkylenepolyamine such as diresins the preferred compounds are alkylenepolyamines, since these form colorless resins with halohydrins whereas the corresponding resinous condensation products of the arylenepolyamines are likely to be highly colored.
The alkylenepolyamines used in preparing the resins employed in practicing our invention are well-known compound corresponding to the formula H2N('CnH2n.HN)mH in which a: is one or more. Typical amines of this class are the alkylenediamines such as ethylenediamine and 1,3- propylenediamine and polyalkylenepolyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine and the corresponding polypropylenepolyamines and polybutylenepolyamines. The halohydrins are derivatives of glycerol in which one terminal hydroxy group is substituted by a halogen atom; i. e., by chlorine, fluorine, bromine and the like. We have found that the presence of a terminal halogen atom in these reagents imparts cationic properties to the resins which they form by reaction with alkylene polyamines, and this is probably the reason why these resins are substantive to cellulose fibers.
The condensation between the polyamine and ethylenetriamine or tetraethylenepentamine with one or more mols, preferably 1-3 mols, of a polyfunctional halohydrin. This reaction is preferably carried out at temperatures below the boiling point of the mixture, usually not substantially higher than 60-'70 C., in order to permit the use of relatively concentrated solutions while obtaining the resin in a hydrophilic or water-dilutable condition. Usually the halohydrin is added slowly to the polyamine, which is preferably dissolved'in water or a watermiscible solvent, at a rate such that the reaction temperature is maintained at about 50-55 C.
When a thermosetting resin is desired the reaction product, after the initial exothermic reaction, may be maintained at 60-70 C. until an increase in viscosity is noted, indicating that the second stage of the resin-forming reaction has set in, after which it is cooled and diluted with water if necessary to form a stable syrup. In some cases, and particularly where a dihalohydrin is being used, sufficient alkali such as sodium hydroxide, sodium or potassium carbonate, or sodium or potassium phosphate may be added before or during the second stage of the reaction to neutralize the syrup by combining with any hydrohalide that is not taken up by the polyamine. quently gives improved results when condensing a polyamine of relatively low molecular weight, such as ethylenediamine, diethylenetriamine, or triethylenetetramine with several molecular proportions of a monohalohydrin such as epichlorhydrin in the preparation of a thermosetting resin. If desired the syrup may be subjected to a vacuum distillation after the first stage of the reaction is completed to remove any unreacted epichlorhydrin, dichlorhydrin or other polyfunctional halohydrin.
This alkali addition also fre-' accuser Anywater insoluble coating or impregnatingagenz m'ay be applied -by the process of "the in ventfon in amounts 1 varying from. a' few per cent"u'p' to-more than the weight of thefibrou's cellulosic material. By "coating orimpregnatingmgentf 'we mean, of course, a material which will coat or impregnate the cellulosic fibers and immove theirvalue for their intended "use. The
great maj orityof coating andimpregnating materi'als usedin practicinglthe invention are or ga'nio 'amorphous or micro-crystalline materials o=tlie =typeof waxes; gums; resins and the-like. The following I types'oi materials of this' clas's are illustrative of the wide variety of impregnatingtagents that may b'e 'ap'pliedz Waxes.
Paraflln Crudersoale wax Carnauba wax Monte-n wax amorphous petJr o leum wax Chlorinatedwvaxes' Petrola'itum- Bituminous Asphalt Bitumens Tars andpitches Rosins wood rosm Acid-treated or poly- Gum ro'sin merized rosin Het treated rosin- Disproportionated ros- Hydrogenated rosin Limed rosin V Sulfur-treated rosin Elastomers Natural latices Synthetic latices Isoprene polymers Neoprene polymers Butadiene polymers Copolyme'rs of butadiene, isoprene, etc. with acrylonitrile ResinsThermosett-ing Phenol aldehyde resins including particularly the phenol and alkyl-phenol formaldehyde.
moulding resins Pine wood pitch phenol formaldehyde. resin dispersions'(U. S. Patent No. 2,357,091)
Llgriin-phenol-formaldehyde resin dispersions (U. S. Patent No. 2,357,090) Ur'e'ai-aldehyde resins FUrfural-Iormaldehyde formaldehyde resins Alkyd resins Non'cation'ic melamine-formaldehyde. resins Alkylated or alcohol-reacted urea-formaldehyde resins andfurfuryl alcohol- Alkylated or" alcohol reacted melamine-formal V dehyde resins Resins-Thermoplastic Polyvinyl compounds Polystyrene 1 Polyacrylates P'olyrnethacrylates Polyvinyl esters such as vinyl chlorides and". .65.
vinyl acetate polymers and. copolymers of the two,
Polyvinyl acetal Polyvinyl alcohols Copolymers of styrene with vinyl chloride; acrylic acid esters, acrylonitrile, etc. I
Thermoplastic phenol-formaldehyde resins; in
eluding phenol-acetaldehyde" and phenolfurfural resins and-corresponding. resins obtained from eresols and 'other-alkyl phenolsa Oil-modified phenol-formaldehyde resins? Esters 'ofx rosin with polyhyclric.alcohols suchiasi glyceriney pentaerythritol; dipentaerythritolra:
polyallyl alcohols; etc: Resins from melamine: and h-igh'er"aldhydesii Polyindene -resins Coumarone: resins Vinylacetyl'ene resins VinsoP resinpi. e. residuewfrom purifyingwood-fz rosin: HalogenatedJvinylacetylen'e" resins Acetyl gu'ms Any] of the above materials, either singlyor? in adinixtu're, may, beapp'lied to fibrous'cellu' losic materials with the aid of 'cationicalkylenfi polyamine-halohydrinresins i by the process of I the present'invention The impregnating" age t is added Ltd the. aqueous stock" suspension con' j tainingfthe cellulose fibers as a. dispersioii'irfwater" or aqueous liquid. Depending on"the"ty pe of "impregnating agent," the" dispersions niayj 're quire'ino I addediernulsifying or dispersing agents 1 whatsoever, as. in the case of naturallatices. However; in many. cases dispersions "of fineri par-i ticl lsizeif 'a'ndibetter "impregnating properties are obtainediwith" the aid. of dispersi'i'lgiagerits,,and.= many-.types of dispersing agents.v may be 'usee;:'
In'TgeneraL' any. anionic or' non-ionic dispersing;
agent may, 'befemplo'yed in emulsifying; or. 113;;
pending the impregnating l agents in water? oiother} aqueous liquids, and. in certain cases".v the;
cationic emulsifying; agents may. also be used;-
Typi'cal' anionic emulsifying. agents which may; beeneinployed with successare. the-soapsof aliphatic. and 'cyclo-aliphaticacids such as.
tassium .oleate, potassium lnaphthenat'e. and the like, amine soaps such as triethanolami ne oleate}; sulfated. aliphatic compounds such} as sodium lauryl sulfate and the sulfatesof higherlsecond aryI alcoholsand; sulfonated castor oilj su-lfo- 'nated. products. such: I asllsodium keryl benzene sulfonate, sodium: isopropyl. naphthalene sulfol Irate}; esters..otlsulfocarhoxylic acids sueh as es-; tersl o-f sodiuinisulfoacetate, dialkyl "sulfosuc'cifnates, .dis'odiuni-lmonoalkyl I sulfosucciriates'; amidesiof .suliocarboxylic acidssuch as. sodium sulffo'succin'amates and'lthe. like, sulfonated ligninl etc.
nona dmc' emulsifying agents such'.a o1yhy-'- v dric .alcoh'ol Les't'ers .andiethers may alsohe usedy. 'rypic rcompounds of thisclass are-polyethylene) lycol-substituted m aleic.acid- .'estersl-of--.the Jer mula.
rnannitan and sorhit'an Inonoesters; ofhigher fatty'aeidsisuch as palmitic, stearic and oleic acids I and their ethylene. oxide condensation prodi'i'cts' and 'arylealkyl polyether alcohols.
Another class ofcompounds that may =be used 6 either as .emulsifyingagents or as emulsion stabilizers..ar'e' the gums and proteins. Thus; tim example,"- gum arabio may loe used, as '--well assoy-aab'ean protein; sodium alginateeandthe l ike-.'-. Ammoniumcaseinate' is another; etn-ulsifiying. agentthat" 'has .cbteen used with: success.
Ammonium or otherwater-soluble" or water! dispersible salts o'fflalkyd resins of high .acid
number may" also be employed; such asthe puss ucts" obtained by adding sod um "'hydioi ideito condensation products of maleic acid "and glyceriner modified? plithalic anhydridegglycerlne f any ac-id -'-con'densa-tion'= products of high acid number; polyhydric alcohol, esters of t'erpen malelctacid conderisation products andme like:-
1 In? generals. thereloreianysuitable wetting or emulsifying agent may be used in practicing the invention.
Any fibrous cellulosic material capable of adsorbing cationic polyamine, halohydrin resin from an aqueous solution thereof may be coated or impregnated by the process of the invention. A wide variety of fibrous cellulosic material used in the preparation of paper, board, moulded resin fillers and the like may be used, such as Kraft pulp, rag pulp, soda, sulfate, ground-wood, sulfite pulp and alpha pulp. Similarly, other forms of fibrous cellulose such as cotton linters, and the like may be employed. These materials may be used alone or in admixture with fibers from other sources, such as jute, hemp, sisal, strings, chopped canvas, asbestos. fibers, glass fibers, and other material, either cellulosic or noncellulosic, that may improve the impact resistance, mechanical strength or other properties of the formed or moulded impregnated material. Typical products that may be improved by the process of the invention are waterproof or moisture-vaporproof paper, paper or board containers or cartons for milk, butter, foods, etc., resin-impregnated laminating paper, abrasives composed of resin-impregnated paper coated with abrasive particles, moulded articles, premoulded articles, electrical insulators, filter paper, heat-insulating paper, or loose masses of unfelted and unmoulded impregnated cellulose stock used for air filters, dust filters, heat insulation and the like.
The particular procedure whereby the impregnating agent'is flocculated and coated on the fibrous cellulosic material may vary somewhat with diiferent impregnating agents, but usually follows the same general plan. The cellulosic material is preferably first suspended in water and may be-beaten for shorter or longer periods of time, after which the stock may be brushed out in a Jordan engine or other refining machine if desired. Any desired ratio of cellulosic material to water may be maintained, but we prefer to operate at a stock consistency of about 0.5% to 6%. The cationic alkylenepolyamine-halohydrin resin is then added, preferably in the form of an-aqueous dispersion of about -l5% resin solids, after which the stock suspension is preferably allowed to stand for anywhere from minutes up to 3-4 hours or longer., This period of standing is not a necessary step, since the adsorption of cationic resin by the paper pulp is quite rapid, but the subsequent behavior of the impregnated stock on a papermaking machine is much better when the addition of the impregnating agent is delayed'for-this period of time. The pH of the stock during the adsorption of the cationic polyamine-halohydrin resin and prior to additiongof-the impregnating agent should preferably be within the range of about 3-8 since the resin retention is not as good at higher or lower values. a
' After pretreatment of cellulosic fibers with the cationic alkylene-polyamine-halohydrin resin,
or less have given excellent results in practice, and therefore we recommend the addition of the impregnating agent in the form of an aqueous dispersion having at most this particle size. The flocculation of the impregnating agent and its adsorption by the cationic resin-treated cellulose fiber is fairly rapid, and the standing time of the mixture after the impregnating agent has been added makes very little difference in the resin retention. The stock can therefore be formed immediately after the addition Of the impregnating agent or after a considerable period of time, as desired. However, a more uniform impregnation of the stock is sometimes obtained when the impregnating dispersion is added slowly to the resintreated stock instead of adding it all at once. In continuous operation, where the resin dispersion is added continuously to a stream of the treated stock, this effect can be obtained by introducing the resin dispersion simultaneously at several points in the stock-treating system. Also the point of addition can be selected so that the time of contact available for flocculation before sheet formation is adjusted to give maximum flocculation.
The optimum quantity of the colloidalpolyamine-halohydrin resin that should be used to obtain the best retention of a dispersed or emulsified resin, wax, or other impregnating agent may vary with the nature and particle size of the dispersion, the nature of the cationic resin colloid, the time of contact between the pulp fibers and the polyamine resin solution, the pH of the stock and other factors. Also, because of the properties of the dispersed material added and the requirements of the finishedsheet or article to be made, it may be desirable to modify the proportion of polyamine resin'in order to obtain increased properties thereof in the finished product. In general, the proper amount-of polyamine resin colloid-required may vary from small amounts on the order of 0.1%, based on the weight of the paper stock, up to several times the weight of the impregnating agent.- Larger quantities of the cationic polyamine-halohydrin resin are usually, needed to obtain the maximum retention-with decreasing quantities of impregnating agent, but goodretention can be obtained at any desired ratio of impregnating agent to fiber by observing the proper operating conditions. When using relatively large quantities of impregnating agent, on the' order of 100% or more of the weight of the cellulosic fibers, the optimum quantity of cationic resin is within the range of about 15%, based on the weight of resin solids in the impregnating agent. With smaller quantities of impregnating agent, such as 5-50% onthe weight of the cellulose, larger quantities of the cationic resin on the order of the impregnating agent is introduced in the form 2-20% should be used. Larger quantities'of the polyamine resin up to or more on the weight of the impregnating agent may be added to modify the properties of the finished product if desired, but in such cases there is a definite falling off in the retention and also an increase in the drainage time of the stock. It is usually desirable to run trials with the specific dispersion of impregnating agent to be added, using the desired operating conditions, before deciding'finally on the exact proportions of cationic polyaminehalohydrin resin to use.
Although a high degree of flocculation and retention of the added impregnating agent is obtained by the use of cationic polyalkylenepolyamine-halohydrin resins alone, it is sometimes 13 ance. Strong and flexible papers having the properties of leather or cloth can be manufactured by incorporating synthetic or natural rubber latices, elastomers, and resins in suitable proportion. Heating, calendering, and other mechanical processing can be used to enhance the desired properties. Fire or flame resistance may be imparted to paper and paper board by incorporation of such materials as chlorinated waxes, polymers of chlorinated styrene, aminotriazine pyrophosphates such as melamine pyrophosphate and various thermosetting resins. Mineral fibers also maybe incorporated at the same time to assist in obtaining maximum fire resistance.
PREFORMING AND MOULDING synthetic rubber are coated on the fibers in the manner described above, the product can be worked on heated rolls wherein other fillers such as finely divided carbon black or zinc oxide may incorporated together with curing accelerators such as mercaptobenzothiazole and antioxidants if desired after which the product can be cured by heating in moulds in the usual manner.
In the manufacture of large articles of irregular shape from moulding compositions containing a resinous binder together with a cellulosic filler considerable difliculty has been experienced in obtaining adequate draw or flow in all parts of the mould. To overcome this difliculty a technique preforming or premoulding has been developed, in which a uniform mixture of the resinous binder and filler is made into approximately the desired shape of the finished article without curing the resin. The process of the present invention is particularly well suited for preforming processes of this type, since the fibrous character of the filler is retained and therefore the preforming can be done by wet moulding processes. Moreover, there is much less loss of resin in the drainage water when operating in accordance with the principles of the present invention.
Preforms prepared with the aid of cationic polyamide-halohydrin resin solutions will simplify many moulding problems and increase the types of fillers and resins that may be moulded. Wood flour, cotton flocks, kraft paper stock and other standard materials may be used as well as macerated cellulosic fabrics such as canvas, cords and other fillers that impart increased toughness and impact strength to the moulded piece. Any of these fillers, or any desired mixture thereof can be suspended in water, treated with cationic polyalkylenepolyamine-halohydrin resin solution and then impregnated uniformly with thermosetting or thermoplastic resinous binders in the manner described above, after which they can be preformed into the desired shape by straining or forming on a screen or other permeable surfacehaving the desired shape. Losses due to resins dissolved or suspended in the water hours.
passing through the screen are usually less than 10%, and even these small quantities of resin can be readily recovered by reuse of the water. Phenol-formaldehyde and cresol-formaldehyde resins are advantageously applied by this method in amounts of 10100%, based on the dry weight of the cellulosic fibers.
LAMINATING AND MOULDING Sheets and boards impregnated with large quantities of thermoplastic or thermosetting resins by the process of the invention are particularly well suited for laminating and moulding processes by reason of the uniform distribution of the resinous material. Laminating paper is preferably made On an ordinary Fourdrinier machine or on a cylinder machine. Heavier board for moulding purposes is often made on a socalled wet machine; i. e. a paper-making cylinder feeding a drum on which the wet sheet may be wound until board of the desired thickness is obtained. When thermosetting resins are used a curing catalyst such as phthalic acid, oxalic acid and the like may be sprayed on the wet paper before it is dried or, in the case of phenol-formaldehyde resins, hexamethylene tetra mine may be applied as a spray to the dried paper or board. Laminating is accomplished by pressing astack of the impregnated sheets between hot platens. Moulding is accomplished either directly from the paper or board, used as a preform, or after the felted fibrous material is shredded or .chopped to obtain better flow in the mould. Mouldings of high mechanical strength and impact resistance are obtained by this procedure. The invention will be further illustrated by the following specific examples, which show preferred embodiments thereof. It should be understood, however, that the invention in its broader aspects is not limited to these examples, but that other modifications and variations in materials, quantities and procedures may be resorted to within the scope of the appended claims.
Example 1 the temperature of the solution at about 50 C.
Stirring was then continued at the same temper-'- ature for an additional 30 minutes after which.
the batch was stirred at C. for a short time, whereby a 50% resin solution was obtained.
Emulsion No. l: A solution of 1.2 parts by weight of uponol C in 58.8 parts of water was heated to 94 C. and 0.05 parts of 40% hydrogen peroxide were added. To this solution 40 parts of styrene were introduced uniformly during 1.5 hours. The exothermic polymerization reaction proceeded smoothly and was complete after 3.5 Steam was blown through the batch to remove unpolymerized material and the dispersion was adjusted to 25% solids. Duponol C is a higher alkyl sulfate (molecular weight 350) containing 10.8% Nazsoi and 3.4% moisture.
Emulsion No. 2 was a polystyrene emulsion prepared exactly as described for Emulsion No.1, but 2 parts by weight of sodium petroleum sulfonate was used instead of the Duponol C.
Emulsion No. 3: To a solution of 5 parts by weight of Duponol C in parts there was added 0.5 parts of 30% hydrogen peroxide and the solution was heated to 94 C. A mixture of anon-s97 1 5 50*parts by' weight of styrene and 50 parts of ethyl acrylate 'wasintroduced uniformly during 1.5 hours, after which the procedure of Emulsion N':-' 1 was followed.
These-resins were used in the preparation of hardboard. Pine chips were cooked 30 minutes with steam at 100 lbs/sq. in. pressure, and defibered. The pulp was diluted with water to 2% solids, a so'lutionof the epichlorhydrin-polyamine resin was added and mixed thoroughly and the mixture was allowed to stand at least onehalt hour? Thepolystyrene or styrene-ethyl aor ylat'e copolynfer emulsion was then added sloWlyr'and stirringwas continued until the filtrate'trom a sample was clear, showing a good retentibnpfi resin on the fibers;
The stockwas made into board on a handsheet machinebyidiluting to 1% fiber consistency and felting with a vacuum of 11 inches of mercury. The sheets; having an'area 01*72 square inches, were pressed"between a wire screen and a pol ished' steel platen'to remove excess water and the wet'board was hot pressed between 5-inch stops, to"give-"a standard thickness, at 350 F. for 15 minutest'using about 1,500 lbs/sq. in. pressure. The dens'e'boards were cooled under slight pressure'and tested'for modulus of rupture with a conventional beam tester.
In the-following table the amounts of resins are expressed a'sper cent of the weight of the dry fiber used, and these amounts express the actual w elghflof-resin' solids and do not include the weight'of solvent or aqueous phase of the emulstone. The fiber weights are dry weights expressed in grams' while the modulus of rupture is given in pounds per'square inch.
hydrin-polyamine resins; Substantially com.- plete retention of the emulsified thermoplastic resiryisob-tainablewith-as little as 0.75% of the polyamine resin, based on the weight of the fibers, when relatively small amounts of polystyrene: are applied- Larger amounts on the order of-1.5-2% of the l polyamine resin will effect a substantially complete retention of 1 50- 1 00 of polystyrene.
Example 2 IB-gram batches of bleached kraf't pulp, beaten to a Greene freeness of 475500,:weresuspendedin waterv to about 1.5% consistency and treated with varyingamountsof-the epichlorhydrin-tetraethylenepentamine resin described in Example 1. After" 3 hours aging the pH was adjusted to 6.5-7.0 and an emulsion of wax or polystyrene resin was added in an amount equal to the dryweight of the fiber. The mixtures were thenstirred'for'S minutes,- or longer if the filtrate from. a sample remained turbid, and were then-dilutedwithwater to 1 fiber and ZOO-gram portions wereused to form, hand'sheets on: a laboratory-handsheet machine. The retention of wax or resin 'was calculated from the gain in weight of the sheet over the fiber-weight. The followingwax emulsions were used.
Wax. Emulsion No. 1: A mixture of 225 parts by weight of molten scalewax and'22 parts of oleic acidwasadded to 250 parts of hot'water containing 2.6 parts of" NaOH .followed; by heating for-15 minutes and homogenizingsto a smooth emulsion of 1-2- microns particle size.
Wax Emulsion No. 2: 250 parts by weight of molten scale wax were added to'250parts of hot water containing 5-partsof Duponol C followed by homogenizing to a smooth emulsion.
- v Dram Polystyrene Emulsion: This was No. 1 of sa leljiber' 2 3 Amount age Mod. of Example 1. I
No. Weight Resin ge' Rupture 40 In the following tables, which show the results obtained; the top row gives'the amount of" epi- 149 v n 49 2 318 chlorhydrin-polyamine added asv per cent of the 133 0. 75 1 5 71' 51365 dry weight of the fibers and the bottomrow 3g l Z 3% shows theresin retention as percent of the total 70 2,0 1 100 300 111 resin added; i. e. wax or polystyrene plus epi- 53 kg 5 33 chlorhydrin-polyamine resin.. The presence of 126 1.0 s 10 as 111025 cloudiness in the white water after the first mat 91260 of fibers is formed on the screen indicates an These results show that polystyrene and styreneethyl acrylate copolymer resins can be applied to cellulosic fibers in any desired proporincomplete'flocculation' of the emulsified wax or polystyrene by the cationic resin, whereas a clear white water indicates an: almost complete-'fiocculation.
WAX EMULSION NO. 1
Per cent Cationic Resin. 0 1 2 s 5 1o Dra nage Time, sec .l 33 42 43 40 35 Wh1te-Water Clear Cloudy Cloudy Sl; cloudy Clear I Clear SheetWe1ght,grams 2.03 2.29 2.96 3. 53 3. 67 3. 61 Retention 12.9 45.6 72.8 78. 2 71.8
WAX EMULSION NO. 2
Per cent Cationic Resin. 0 1 2 3 5 10 Drainage Time, sec 19 42 41 36 35 34 White Water Clear S1. cloudy Clear Clear Clear Clear Sheet Weight, grams. 2.02 3. D0 3. 3. 65 3. 67 3. 59 Retention 48. 5 75.0 79. 2 78. 7 71. 4
POLYSTYRENE EMULSICN Per cent Cationic Resin. 0 1 2 3 5 1D Drainage Time, sec 18 22 55 8O 71 52 White Water Clear Cloudy' Clear Clear Clear Clear Sheet Weight, gram 1. 97 2. 3. 79 3. 80 3. 3. 92 Retention 43. 1 89. 3 88: 9 91. 8 88. 7
tlons up to of the weight of the fiber with- These'results show that goodretentions of out diificulty by" the application. of cationic halowaxes" and" resins are obtained when relatively small amounts of halohydrin-alkylenepolyamine resins on the order of 1-10'% are used, even with quantities of impregnating materials equal to the weight of the cellulose fibers.
18 solution of 40 parts of 10% potassium stearate and 0.5 parts of sodium isopropyl naphthalene sulfonate in 24.5 parts of water followed by homogenizing to a particle size of 1-2 microns.
with 4 mols of fumaric acid and 2 mols of phthalic anhydride for about 8 hours at 180 C. This resin is dissolved in about 25% of its weight of diallyl phthalate. 35 parts by weight of this product are agitated while adding a Example 3 5 -Alkyd Resin Emulsion B: A solution containing 1.6 parts by .weight of gum arabic, 0.5- parts The procedure of Example 2 was followed, but of lignin sulfonate. p rts of boric acid and a thermosetting polyamine-halohydrin prepared .8 p r o water is pr p and mixed Wi h by the following prgcedure was used; 47.5 parts Of the same alkyd resin 50111131011. A solution of 37.8 parts by weight (0.2 mols) 10 This mixture is homogenized to 1-2 microns parof tetraethylenepentamine in 93 parts of water ticle size. was prepared and epichlorhydrin was added yp p olo m d yd es emulsion slowly with stirring at a rate such that the reare: action temperature did not rise above 50 C. Phenol Resin Emulsion: A mixture was pre- After 35.5 parts (0.6 mols) of epichlorhydrin pared containing 200 parts by weight of phenol, had been added the stirring was continued at 146 parts of 37% aqueous formalin, 0.3 parts of 50 C. until the product became viscous. The sodium alkyd sulfate Wetting agent (molecresulting hydrophilic colloid was diluted with ular weight about 300-330), 2.8 parts of water to a 15% solution. 7 methyl cellulose, 2 parts of 18.4% hydrochloric The wax emulsions and polystyrene emulsion acid and 200 parts of Water and heated with were the same as in Example 2. The results are agitation for about 40-50 minutes at 9G-100 shown in the following tables, where the figures C., or until a phenol-formaldehyderesin emulhave the same meaning as the corresponding sion was obtained. figures in that example. Bleached kraft paper pulp was beaten to a WAX EMULSION N0. 1
Per cent Cationic Resin. 0 2 3 4 5 10 Drainage Time, sec 37 40 33 33 White Water Clear Cloudy Cloudy 81. cloudy Clear Clear Sheet Weight, grams 2.07 3. 25 3.27 3. 38 3. 63 3. 83 Retention 57.9 58.3 1 63.1 74.3 80.0
WAX EMULSION No. 2
Per cent Cationic Resin 0 l 2 3 5 10 Drainage Time, sec. 21' 16 28 25 23 44 White Water Clear Cloud Clear Clear Clear Cloudy Sheet Weight, gram 2.09 3.56 3.65 3.58 3. 61 3.31 Retention 72. 8 76. 6 72. 4 72. 4 55. 5
POLYSTYRENE EMULSION Per cent Cationic Resin. 0 1 2 3 5 10 Drainage Time, sec 20 10 15 34 60 83 White Water Clear Cloudy S1. cloudy Clear Clear Cloudy SheetVVeight, grams 1.97 2. 42 3. 40 3.87 3.86 3.11 Retention 22.3 70.2 92.3 90.2 51.8
Example 4 Greene freeness of 475-500 and then used to make a number of stock suspenslons, each containing The principles of the present invention may sufiicient fiber to make a sheet weighing apbe applied to the impregnation of cellulosic fi- 5O proximately 2 grams suspended in water at 1.5% bers such as groundwood, steam-treated or exconsistency. Cationic tetraethylenepentamineploded wood fibers, kraft paper stock or othe epichlorhydrin resin solution was added to some types of paper" pulp with emulsions of thermoof these suspensions in the amounts indicated setting resins such as phenol-aldehyde resins, below, the remainder being used as controls, and alkyd resins and the like. One important class the suspensions were allowed to age 3 hours beof l y ins hat may be u d f r i pr sfore treatment. The pH of the resin-containing n io r co in y i m tho i th h rsamples was then adjusted to 6.5-7 and one of 11108617131113 p yba 0 dD01y y 0 31001101 the above-described resin emulsions was added in alkyd resins op lym rized with a polym ri l the amount indicated in the following tables. unsaturated organic compound having a boil- The stock was then made into handsheets on a ing point above 60 C. which contains at least small sheet-making machine provided with a one I-I2C'=C group and is freefrflm double bon graduated glass stock cylinder so that the rate y s in co j at t ew 511 38 yr of drainage could be measured accurately. The and m yl Styrenes, lyl p l m yl sheets were dried at 160 F. and weighedand the methacrylate, 571 maleate fllmarate and total resin retention and resin content was dethe likeyp c resin emulsions Of this Class termined from the increase in weight. In the are the following: following tables the per cent of cationic resin is A ky R si Emulsion A! All alkyd resin is based on the actual Weight of resin solids in the p pared by heating oi/m 0f nr101$ 0f emulsion added and the per cent of emulsion ethy ene glycol a 3 111015 of (1181711316116 7 represents resin solids based on'the dry weight of the fiber. The degree of clarity of the white water is determined after a mat of fibers has been formed on the sheet-making wire, and indicates the completeness of flocculation of the dispersed resin.
ALKYD RESIN EMULSION A Per Cent Drainage I Percent Per Cent White Dry Sheet Per Cent 4 oatlqmlzrnesmyof 1235 Emulsion 33? Water Wt. Grs. Retention gi I None None 2.00 2 13s 22 2-: @9
2 22 2-2 2-2 Example 3 150 4. 63' 78: s '3 ALKYD RESIN EM None None 17 2.07
100 2G S1. 3. 22 5. 64 35. 8 Example l cloudy 5 100 24 d0 3. 03 45. 7 31. 7 10 100 23 Clean-.. 3. 40 60. 5 39. 2 2 2 2 23-; 2; 5' 100 2 on y 3 1c 100 Very 2.74 30.4. 24. 4
PHENQL RESIN EMULSION None 2.11 100 3. 38 5 100 3. Example 1 g g: 24
Example 5 The finalemulsion contained 40% of coumarone Coumarone Resin No. 1: An solution of Cumar RH in xylene was prepared and 50 parts by weight were added to an aqueous solution prepared by dissolving 2 parts by weight of 25% sodium dioctyl sulfosuocinate and 1.5 parts of Tween 40 (a condensation product of ethylene oxide with sorbitan monopalmitate) in 46.5 parts of water. The mixture was homoge nized to an emulsion of fine particle size to'which. 20 parts of water were added. The xylene was then stripped out in a distillation column, leaving a dispersion containing 45% of coumarone in wat r. o u 0n.c nta n e.2% i-fimul i ine agents.
Coumarone Resin No. 2 The sameern-ulsifying procedure. was followed but Cumar DX," a
resin and 2% emulsifying agents.
Batches of bleached kraft pulp was suspended in water and pretreated with l% of. the epichlorhydrin-tetraethylenepentamine resin of Example 1 followed by adding one ofthe above coumarone resin emulsions and forming the stock into sheets, using the procedure described in Example 2. The sheetswere dried to constant weight by heating at F. "The amounts ofresin added, based on the dry weight of the pulp, and m r suits obtained are given in the following table, wherein the water absorption is the amount taken 45 up after soaking 2 minutes in cold water, ex-
pressed as per cent of the dry weightof the paper, and the tensile. strength; is given in pounds per inch width.
lensile Stren th Stiffness 1 Sheet Percent Basis g G "may: No. in Sheet Weight r 4 Dry Wet Dry Wet :12am NO. 1
None 1215 57.7. 2.0- 159. 227.5 14. 2. 123. 0 59.2 19. 7 s9. 5 365.8 25; s 122. 0 5s. 5 19:7 59; 5 549. 7' 25.1 125.0 52.5" 18..8. 62:7 4422 40.9 128.0 43.4 28.4 40.6 355.2 1-F.-.. 52o 146.0 51.6 22.0 43.10 555; 0
RESIN NO. 2
16. s 117.5 51. 5 1s. 3 1 27. 1 1254. 1 29 9. 7 25. 0 124. 5 40. 9 15.4 105. 2 1221. 0 305. a 33. a 124.0 42. 0 12.10 103.. 5 1021: 4 222; o 41. 2 121. 0 5s. 2 12.6 93.8 343. 6 183. 2 49. 2 127. 5 as. 1 12. 1 75. 9 842.. 5 244. 3
somewhat darker coumarone resin, was used.
The sheets were then pressfid for. .5. minutes at 21 500 lbs/sq. in. between platens heated at 150 F. after which the water absorption, tensile strength and stiffness were again determined. The results were:
Tensile Strength Per Cent Stiflness-Gurley Water Sheet No. Absorp Dry Wet tion Dry Wet RE SIN N O. 1
RESIN NO. 2
2-B 66.0 19. 2 86. 6 1043. 4 321. 9 2-0 70. 2 24. 4 62. 7 1122. 2 383. 0 2D 50. 1 16. 4 66. 6 854. 7 267. 0 2-E 51. 5 19. 0 51. 3 510. 6 194. 3 2-F 48. 9 21. 2 43. 1 721. 5 299. 7
These results show that coumarone resin can be applied by the process of the invention for the manufacture of board, such ascorrugated boxboard, and that greatly increased wet strength and substantial improvements in other properties can be obtained therewith.
Example 6 A solution of 94.5 grams (0.5 mols) of tetraethylenepentamine in 492 grams of water was prepared and 161.2 grams (1.25 mols) of dichlorhydrin (C1CH2.CH(OH).CH2C1) was added slowly with agitation while maintaining the temperature below 20 C. The syrup was then cooled to 10 C. and a solution of 51.5 grams of 97% NaOH in 150 grams of water was added. The mixture was agitated for 3 hours to initate the formation of a thermosetting resin. The resulting resin syrup had a pH of 8.0 and a solids content of 22%.
A water suspension of grams of bleached Kraft paper pulp, diluted to a fiber consistency of 1.56%, was treated with a quantity of the above resin syrup such that 5% resin solids were added, based on the dry weight of the fiber. After adding the resin the suspension was allowed to stand for several hours at a pH of 5.1. The pH was then adjusted to 6.5 with dilute sodium hydroxide solution and a quantity of the polystyrene emulsion No. 1 of Example 1 was added equivalent to 15 grams of resin solids, or 100% resin on the weight of the fiber. The mixture was diluted with water to 1500 grams, so that the suspension contained 1% by weight of fiber and was stirred 15 minutes. ZOO-gram portions were then made into paper on a laboratory handsheet machine along with an equal number of control sheets containing no resin.
The average dry weight of the sheets prepared from the resin-treated stock was 3.83 grams. whereas the average of the blank sheets was 2.09 grams, thus indicating an 83% retention of the resins.
What we claim is:
l. A method of impregnating fibrous cellulosic material with a hydrophobic organic impregnating agent while preserving the freeness and felting properties thereof which consists in preparing a water suspension of the fibrous cellulosic material at (LE-6% consistency, adding to said suspension a hydrophilic cationic alkylenepolyamine-epichlorhydrin resin in amounts of 1-20% of the weight of the organic impregnating agent,
aging the suspension at a pH of about 3 to about 8 for at least 30 minutes, then adding an aqueous dispersion of the impregating agent in defioc- 5 culated condition, fiocculating the impregnating agent in the cellulosic fibrous suspension by the action of the cationic alkylenepolyamine-epichlorhydrin resin, and thereby depositing a substantial proportion of the impregnating agent uniformly on the fibres.
2. A method of impregnating fibrous cellulosic material with approximately 50100% of its Weight of a hydrophobic organic impregnating agent which consists in preparing a water suspension of the fibrous cellulosic material at (XS-6% consistency, adding to said suspension a hydrophilic cationic polyamine-epihalohydrin resin in amounts of at least 1% of the weight of the organic impregnating agent, aging the suspension at a pH of about 3 to about 8 for at least 30 minutes, then adding the requisite quantities of an aqueous dispersion of the impregnating agent in defiocculated condition, fiocculating the impregnating agent in the cellulosic fibrous suspension by the action of the cationic polyamineepihalohydrin resin, and thereby depositing approximately 50-100% by weight of the impregnating agent uniformly on said fibres, said weight of deposited impregnating agent being based on the weight of said fibers.
3. A method of impregnating fibrous cellulosic material with approximately 50-100% of its weight of a hydrophobic organic impregnating agent which consists in preparing a water suspension of the fibrous cellulosic material at 0.56% consistency, adding to said suspension a hydrophilic cationic alkylenepolyamine-epihalohydrin resin in amounts of at least 1% of the weight of the organic impregnating agent, aging 40 the suspension at a pH of about 3 to about 8 for ,at least 30 minutes, then adding the requisite quantities of an aqueous dispersion of the impregnating agent in defiocculated condition, fiocculating the impregnating agent in the cellulosic fibrous suspension by the action of the cationic alkylenepolyamine epihalohydrin resin, and thereby depositing large quantities on the order of 50100% by weight of the impregnating agent uniformly on said fibres, said weight of deposited impregnating agent being based on the Weight of said fibers.
4. A method for the production of felted fibrous cellulosic material having a uniform content of a hydrophobic organic impregnating agent which consists in preparing a water suspension of the fibrous cellulosic material, adding to said suspension a solution of hydrophilic cationic polyamine-epihalohydrin resin, aging the resulting suspension at a pH of about 3-8 for at least 30 minutes, adjusting the pH of the suspension to about 6.5-7.0, and then adding an aqueous dispersion of the impregnating agent in a deflocculated condition, fiocculating the impregnating agent in the cellulosic fibrous suspension by the action of the cationic polyamine-epihalohydrin resin and thereby depositing a substantial proportion of the impregnating agent uniformly on the fibres and forming the impregnated fibres into a felted product while draining the suspending water therefrom.
5. A method of incorporating a water-insoluble hydrophobic impregnating agent uniformly into fibrous cellulosic material which consists in adding a hydrophilic cationic polyamine-epihalohydrin resin to a water suspension 01 said fibrous llul siq ma e e dd. eta-sa d suepe sion an aq ous: i s qn v he m eenetine agent n efl w k n i qn t me pmn unctsleqte rom he ro qns st i :Q an on n9 n9 qn mulei y n z'; a ents, fl w 1 the mpr ena neagent by the: ag pn the. atiQni po yam neen haloh slr n. resin, in; the, cellulqsic fibrous suspension and .therebxi depositing, a .substantial. proportion of the impregnating agent uniformly on the fibres.
6. In a. method, of: making; a." formed cellulosic productnby. the steps of. preparing an, aqueous suspensionofrfibrous cellulosiwmaterial; impregnating the cellulosic materialwith. awaterw-insoluble. hydrophobic organic impregnating agent and formingthe impregnatedcellulosic material into, a. felted. produet; the. improvement; which consists, in first addingia, solution ofahydrophilic cationic polyamine-epihaiohydrin resin v to n the aqueousifiherv suspension, then adding an-aqueous dispersion of y the impregnating; agent: in" deflocculated condition and; flocculating/ the impregnating agent .in thenceliulosic, fibrouswsuspension by the action of the cationic pglyagnine-epihalohydrin resin and ,therebyJdepositing a substantial 1 proportion ofthe impregnating.- agent uniformly on the. fibers.
7. Aimethod according?to.;,c1aim6:?in1,whicl the polyamine-epihalohydrm is; an alkyienepolyamine-epichlorhydrin resin;-
UNITED STATES PATENTS Number Name, Date 1,392,589, Tucker Feb. 26,1935 2404;092, Mupz et a1, Jan. 4, 1938 2,136,928 sc 1 1 Nov. 15,1938 2,223,930 Gniessbaeh e Dec. 3, 1940 2,228,514. Gniessb achm Jan. 10, 1941 --.J=.- A g. 51 2325392 Britt July-27, 1,943
02- Senur G cher Wohnsiedler etal. Mar. 28, 1944 Meye1; July 18, 1944 Ericks Aug, 7, 1945 Bo 1 1 ard1 Feb. 5, 1946 2401:92 7 Tau z MaM Bi 19% 1 735 6; MflX 1 Sept; 10,1946 2. 239; E IiQ S --v..-. 4--- J Z ..-.l 1 '9&7 2 ,469,683 Dudley etwaL V V May.10,v1949 2, 14,50 w -.--,-e--?. ,-,--.-..-.11111 8128; 1949 v 2,,48 7.,899.= Nov 15,;1949 49 ,70 v v, ,v D si 22.19 49 2,563,897 Wilson,et a1,, Aug, 14, 1951 OTHER: REFERENCES Pacific Pulp and." Paper Industry, Apri1'1943, pages 6 to 8.
Rayon. Eextile Monthly,- Mar. 1-9514, page: 79 73.9)..-
IndustriaizuErmineeringfihemistry, Jan. 1939. pa e 1-
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