US3423389A - Rosin compounds of improved color and stability - Google Patents

Description

United States Patent Of] ice 3,423,389 Patented Jan. 21, 1969 14 Claims ABSTRACT OF THE DISCLOSURE The color and color retention of tall oils, tall oil fractions, rosins and rosin compounds are improved by adding about 0.01% to 1% of a phenol sulfide monomer or polymer and heating at 180-350 C., preferably under a blanket of nitrogen, until products of better color characteristics are obtained.

This is a continuation in part of two copending applications of Charles G. Wheelus, Serial Nos. 579,851 and 579,819, filed on September 16, 1966.

Application Serial No. 579,851 is a continuation-in-part of Serial No. 496,660, filed October 15, 1965, which became abandoned after the continuation-in-part application was filed.

Application Serial No. 579,819 is a continuation-in-part of Serial No. 496,667, filed on October 15, 1965 and Serial No. 560,866 filed June 27, 1966, both now abandoned.

This invention relates to methods for improving the color and color retention of tall oil, tall oil fractions predominating in fatty acids, tall oil fractions predominating in rosin acids, rosins and rosin compounds including tall oil rosin, wood rosin and gum rosin and compounds thereof. The invention includes methods wherein these materials are subjected to heat treatments at bleaching temperatures within the range of about 180 C. to about 350 C. in the presence of small quantities of a particu larly defined class of phenol sulfide bleaching and color stabilizing agents and for times such that improvements in color characteristics are obtained. The invention also includes the improved tall oils, tall oil fractions, rosins and rosin compounds obtained by these methods, all of which are characterized by a lighter color and an enhanced color stability as compared with the raw materials from which they were obtained.

Tall oil is a mixture of rosin and fatty acids released by acidulation of the black liquor soap skimmed off the black liquorthe concentrated alkaline digestion liquor Washed out of paper pulp in the sulfate or kraft process for manufacture of paper. The crude tall oil is then commonly fractionally distilled to provide various cuts ranging from rosin-fatty acid mixtures having a fatty acid content as low as about 1% by weight and rosin content as high as about 99% by weight, usually up to about 90% by weight, to other such mixtures wherein the rosin content is below about 1% by weight, e.g., 0.3% by weight,

and the fatty acid content is as high as about 99% by weight, e.g., 99.3% by weight.

The term tall oil fractions predominating in fatty acids is employed herein to mean crude, solvent/acidrefined, and distilled tall oil portions as Well as tall oil fractional distillation products, each having a fatty acid content of at least about 50% by Weight, the balance being mainly rosin acids in admixture with minor amounts of unsaponifiable materials of complex chemical constitution. The fatty acids consist mainly of a mixture of oleic, linoleic, conjugated linoleic, palmitic, and stearic acids together with lesser amounts of palmitoleic, higher molecular weight saturated acids such as arachidic (C behenic (C acids, higher molecular weight unsaturated and polyunsaturated acids, and low boiling monobasic and dibasic acids.

Preferred tall oils treated according to the present invention are the commercially available acid/solvent-refined tall oils. Typically, these are crude tall oils which have been slurried in a hydrocarbon solvent such as hexane, in a weight ratio of about 40 parts tall oil to 60 parts hexane, then treated with about 8-12% by weight of 96-100% concentrated sulfuric acid at about 35 C., and separated. Such refined tall oils generally contain about 50% by weight or more of fatty acids, the balance being rosin acids, dimerized rosin acids, and unsaponifiable materials.

Other preferred tall oils are the commercially available tall oil fractions containing a minimum of by weight fatty acids and a maximum of 5% by weight rosin acids, the balance being minor amounts of complex unsaponifiable materials.

Light color and color stability are important characteristics for commercial acceptance of tall oil fatty acids and end products prepared therefrom. Thus, tall oil fatty acids are conventionally saponified, amidated, aminated, condensed with ethylene oxide and esterified to provide a host of household and industrial products such as soaps, synthetic detergents, disinfectants, wax emulsions, paper chemicals, coating compositions, epoxy esters and other well known products.

A method commonly employed to improve, i.e., to lighten, the color of tall oil fatty acids involves dry-blending and heating the fatty acid fraction with an adsorbent material such as activated clay. Fullers earth, activated carbon or the like to remove color bodies. The tall oil fatty acid is thereafter separated by filtration and the clay discarded.

To stabilize the resulting improved color, it has become conventional to add known oxidation inhibitors.

While effective, the prior art methods of bleaching and stabilizing tall oil fatty acids have serious deficiencies. Thus, some of the fatty acids will be adsorbed with color bodies onto the adsorbent materials and subsequently lost when the adsorbed material is discarded, thereby adding to the expense of the recovered bleached product. Furthermore, a second treatment with an oxidation inhibitor is often required to stabilize the improved color. This further increases the expense of the final product.

An object therefore of the invention is to provide a method of bleaching tall oil fractions predominating in fatty acids while simultaneously substantially stabilizing the improved color.

A further object is to provide a method of bleaching, and substantially stabilizing the resulting improved color of tall oil fractions predominating in fatty acids by a simple treatment which avoids fatty acid loss and eliminates or substantially reduces the expense of prior art multi-step methods.

Another object is to provide tall oil fractions predominating in fatty acids having improved color and color stability.

By rosins and rosin compounds is meant abietyl com pounds, i.e., hydrophenanthrene radical-containing materials, including but not limited to the following: tall oil rosin, tall oil fractions predominating in rosin acids, i.e., containing at least about 50% by Weight of rosin acids; wood rosin; and gum rosin; modifications of these products such as hydrogenated rosins, formaldehyde-treated rosins (such as described in US. Patents 2,934,468 and 3,132,127). Diels-Alder reaction products such as fumarated rosins and maleated rosins; derivatives of such rosins including rosin esters, rosin amines, rosin amides, rosin alcohols, rosin-alkylene oxide adducts; and the numerous well-known equivalents of the foregoing materials. The term rosinyl, as defined in US. Patent 2,l54,- 629, is a convenient representation for the rosins and rosin compounds of the present invention.

Rosin esters include reaction products of rosin and monoand polyhydroxy alcohols'such as methanol, ethanol, butanol, ethylene glycol, pentaerthritol, glycerol, and the like. Among the many well-known rosin amines may be mentioned the products prepared by dehydrating the ammonium salt of rosin to the nitrile which is then re duced by hydrogen to the amine. Rosin amides are conventionally prepared either by decomposing ammonium salts of rosin or by reacting rosin with primary amines. Rosin alcohols are conventionally prepared by reduction of the corresponding rosin esters. Rosin-alkylene oxide adducts include the known reaction products of rosin and ethylene oxide and the like.

It is important in many end uses of rosin compounds that the starting material be light-colored and that the color remain stable under normal conditions of use. Thus, rosin compounds are widely employed in the manufacture of paper size, as plasticizers for films such as poly ethylene and polypropylene, and for the manufacture of rosins used in paint and varnish. In these and other end uses the industry desires a light colored product which also exhibits color stability. Hence, industry looks for these properties in the rosin compound intermediates used to make these products since good color and stability is normally retained in the end product.

It is known that rosin compounds may be bleached somewhat by heating at elevated temperatures or by treatment with sulfur, sulfur dioxide and similar substances. However, the degree of bleaching often is poor and the treated compounds do not exhibit good color stability. Furthermore, substantial amounts of the treating agent, e.g., sulfur, are often required, thus adding to the expense of treatment. Distillation and crystallization are also employed to achieve bleaching but these methods require elaborate apparatus and extended processing time and thus substantially increase the expense of the treated products. Other problems encountered in prior art bleaching methods include retention of the odor of the treating agent in the rosin compounds (particularly objectionable if sulfur) and tendency to form unsaponifiable materials during the treatment.

An object of the present invention is to provide light colored rosin compounds which also exhibit color stability.

A further object is to provide a method of bleaching and stabilizing rosin compounds without substantial effect on other properties of the compounds, particularly formation of unsaponifiable materials.

A still further object is to provide a low cost method of bleaching and stabilizing rosin compounds which requires only catalytic amounts of a treating agent.

These and other objects, features, and advantages of '7 the invention will become more apparent from the description which follows:

The rosin compounds are bleached and stabilized by treatment with minor amounts of a treating compound of Formula I at elevated temperatures for a time sufficient to effect bleaching. Very small amounts of the additive are effective and may be termed catalytic amounts, e.g., from about 0.01% to 1.0%, preferably 0.02% to 0.5%, by weight of the treating compound based on the weight of the rosin compound.

The range of temperature and time of treatment will vary depending on the type of rosin, modified rosin or rosin derivative employed. Little or no bleaching is observed in the absence of heating or if the rosin compounds are heated in the absence of the treating compound. Normally, the rosin compound is heated in the presence of the treating compound at a temperature in the range of from about 180 C. to 350 C. for up to about 18 hours, the longer times corresponding to the lower temperatures and vice versa. A maximum bleach of tall oil rosin is observed in 30 minutes in a temperature range of about 250 C. to 275 C. at a treating compound concentration of 0.1% and substantially instantaneous bleach is observed at or above 300 C. The higher temperatures generally promote lighter colors when the treating compound concentration is held constant but excessive temperatures should be avoided since degradation and excessive formation of unsaponifiable materials may result therefrom. Optimum bleaching and color stability is obtained for most of the rosin compounds when the same are treated with about 0.1% to 0.5% of the treating agent at 240 C. to 275 C. for about 30 minutes to one hour.

To avoid oxidation, the treatment is generally conducted under a blanket of inert gas such as nitgrogen, carbon dioxide, steam and the like.

In accordance with the invention the above and other objects are accomplished 'when the tall oil or fraction thereof or rosin or rosin compound is heated at an effective temperature within the range of about l350 C., hereinafter sometimes called a bleaching temperature, in the presence of effective amounts of a treating com pound of the formula where n is an integer from 1 to 3 inclusive, p is an integer from. 0 to and preferably about 5 to 20 inclusive, and

the sum of m and n on each Aryl is: preferably between 1 and 5*inclusive. R is a hydrocarbon group, e.g., alkyl, cycloalkyl and substituted alkyl, e.g., C -C wherein the substituents are cycloalky], aryl, alkaryl, and the like and desirably contains from 1 to 22 carbon atoms inclusive. Preferred alkyl groups are straight chain secondary and tertiary alkyl groups containing up to 8 carbon atoms inclusive. Preferred Aryl groups are those containing 6 to 18 carbon atoms inclusive typically phenyl,

naphthyl and anthracyl. Typical cycrloalkyl groups contain 3-8 carbon atoms in the ring, e.g., cyclopropyl, cy' clopentyl and cyclohexyl.

In Formula 1 when Aryl is phenyl it will be apparent that when p is 0 the sum of m and n on each phenyl ring will not be more than 5 and when p is 1 or higher the sum of m and n on each phenyl ring will not be more than 4. It will also be apparent, however, the values for n and m may range higher, when Aryl is naphthyl or anthracyl, since when p is O or at least 1 more than 5 or 4 sites, respectively, are available for OH and R substituents. The values for m, n, x and p, except when 0, are positive, whole numbers.

Included are compounds and position isomers having R groups of mixed character, i.e., the R group or groups on one aryl ring may differ from the R group or groups on the other aryl rings; In and 11 may be the same or different for each aryl ring; and when more than one R group is present on an aryl ring, such groups may be identical or different.

The term treating agent" or treating compound," or like term, is intended herein to mean compounds defined by Formula I above.

From the repeating unit of Formula I above it will be seen that the invention includes not only the use of thiobis compounds (p equals 0) but also higher molecular weight materials, for example, where p is 100 or more, provided sumcient sites are available for polymerization, e.g., the sum of n and m where aryl is phenyl does not exceed 4. The upper limit of molecular weight is dependent only upon how the compound is made, e.g., whether the material is sufficiently fluid in the reaction medium for polymerization to continue, and upon use conditions, e.g., whether the material can be effectively admixed or blended for good contact with the material to be bleached. Ob-

viously, a polymer of such high molecular weight as to be unmanageably tacky or glassy is to be avoided in the practice of the invention. From the viewpoint of economy and ease of preparation and use according to the invention, preferred treating agents are those which are soluble in the material treated, e.g., compounds of Formula I wherein p is in the range of to about 20.

As typical and non-limiting examples of the treating agents may be mentioned:

Thiobis naphthols, e.g.:

1,1-thiobis( 3-naphthol) 2,2-thiobis(ix-naphthol) 2,2 thiobis phenols, e.g.:

2,2'-thiobis (4-methyl-6-tert.-buty1phenol) 2,2'-thiobis(4,6-dimethylphenol) 2,2-thiobis(4,6-di-tert.-butylphenol) 2,2-thiobis( 4-ethyl-6-tert.-butylphenol) 2,2'-thiobis(4-n-propyl-6-amylphenol) 2,2' thiobis(4-methyl-6-n-octylphenol) 2,2-thiobis(4-amyl'6-tert.-octylphenol) 2,2'-thiobis(4-methy1-6-n-decylphenol) 2,2'-thiobis(4-methyl-6-laurylphenol) 2,2-thiobis [4-methyl-6( 1-methylcyclohexyl phenol] 2,2'-thiobis [4-methyl-6-( l-methylbenzyl phenol] 2,2'thiobis(4'methylpheno1) 2,2-thiobis(6tert.-butylphenol) 2,2'-thiobis(4,6-dilaurylphenol) 2,2'-thiobis(4,6-distearylphenol) 3,3'-thiobisphenols, e.g.:

3,3-thiobis-[methyl-6-(1,1,3,3-tetramethylbutyl) phenol] 3,3'-thiobis- (methyl-6-t-dodecylphenol) 3,3-thiobis (pentadecyl-t-butylphenol) 4,4'-thiobis penols, e.g.:

Thiobis-polyhydroxy compounds, e.g.:

4,4-thiobis(resorcinol), 5,5'-thiobis(pyrogallol) the diand trithiobis variants of any of the foregoing, and higher molecular weight materials corresponding to the repeating unit of any of the foregoing. These and other like compounds are disclosed, for example, in US. Patents 2,670,382; 2,670,383; 2,841,619; 3,060,121; 3,069,384; 3,157,517; 3,211,794 and Compt. rend. 198, 1791-3 (1934), said disclosures being incorporated herein by reference.

Particularly preferred are the polyhydroxy compounds such as 4,4-thiobis(resorcinol) and 5,5-thiobis(pyrogallol), the so-called hindered thiobisphenols, e.g., those wherein each aromatic ring is substituted by one hydroxy group, one bulky group, e.g., secondary or tertiary alkyl group, and one short straight chain (C -C alkyl group, and higher molecular weight compounds wherein p is in the range of 5 to 20. Typical of the hindered thiobis phenols are 2,2-thiobis(4-methyl-6'tertiarybutylphenol); 4,4-thiobis(6-tertiary butyl meta cresol); and 4,4'-thiobis- (6'tertiary butyl ortho cresol). Of the thiobisphenols, the first shows best results and it would appear that as the sulfur atom is shifted away from a position ortho to the hydroxyl and the methyl group is shifted toward the ortho from the para position, bleaching efiiciency decreases. Typical of the higher molecular weight compounds is poly[thio-(resorcinol)] wherein p is 6 to 9.

The conditions of treatment may be varied over fairly wide ranges and are therefore not particularly critical. Likewise, sequence of admixture of treating compound and fatty acid fraction is non-critical. Very small amounts of the additive are effective and may be termed catalytic amounts, e.g., from about 0.01% to 1.0%, preferably 0.02% to 0.5%, by weight of the treating compound based on the weight of the tall oil or rosin or compound thereof. The treating compounds may be employed singly or in mixtures of two or more.

Good bleaching and color stability of tall oil fatty acid fractions is generally achieved by treating them for from about 5 minutes to 5 hours over a temperature range of about 200 C. to 300 C., the lower temperature corresponding to the longer time and vice versa. Preferred conditions are a treatment for from about 15 minutes to one hour over about 240 C. to 275 C., time and temperature being inversely related. Little or no bleaching and colorstabilization is noted below about 200 C., and above about 300 C., decomposition and polymerization sets in, particularly in tall oil fractions containing higher proportions of fatty acids, e.g., to 99%. The process may be conducted at atmospheric, subor superatmospheric pressure if desired, with corresponding temperature adustments. Procedures may be batch, semi-continuous or continuous.

To avoid oxidation, the treatment is conducted under a blanket of inert gas such as nitrogen, carbon dioxide, steam or the like. Additional treatment of tall oil fatty acid fractions to obtain further bleaching and color stability is unnecessary for most end product uses of the fatty acids. However, if desired, bleaching with clay in the conventional manner may be employed as a supplemental treatment to further reduce the color. Other stabilizing treatments likewise may be employed if desired, such as the addition of oxidation inhibitors and the like.

From the foregoing description, and also from the examples appended hereto, it will be seen that the present invention is based on the discovery that tall oil and tall oil ingredients, including particularly rosins and rosin compounds, can be bleached to lighter and more colorstable products by heating them in the presence of the phenol sulfide bleaching agents described. The present inventor, jointly with Joseph James McBride, has also discovered that these same phenol sulfides are also disproportionation accelerators or catalysts so that disproportionated rosins can be obtained when rosins containing them are heated at from about 250 C. to 350 C. until their abietic acid content is reduced to less than 15%. It will be understood that this discovery is not claimed as such herein as it is the claimed subject matter of a copending application Serial No. 579,817 filed Sept. 16, 1966 now Patent No. 3,377,324 dated Apr. 9, 1968.

The following is a summary of the subject matter of that application.

Under more stringent conditions of treatment, such as heating rosin at 300 C. or higher in the presence of catalytic amounts (as defined hereinabove) of treating agent, disproportionation occurs simultaneously with bleaching. Generally, disproportionation may be achieved with bleaching when rosin is heated at from about 250 C. to 350 C. for from about 1 to 8 hours, preferably from 290 C. to 320 C. for from about 3 to 6 hours. A conse quence of disproportionation is greatly improved resistance of the rosin to oxidation.

For purposes of disproportionation, rosin includes the treated samples in air at 110 C. (oven) for 1 hour. The color and stability of the feed were 7 and 7+, respectively.

As compared to the colors of the control after each sampling, maximum bleaching was not more than about two points (7- to 5*) on the color scale. However, this is considered a good result in the art, particularly in view of the substantial stability of the improved color.

TABLE I Sta- Sta- Sta- Sta- Sta- Sta- Color bll- Color bil- Color bil- Color bil- Color bil- Color bility lty ity ity ity ity tall oil rosin, wood rosin, gum rosin, crude materials and mixtures containing any of the foregoing, and in general, abietic acid-containing materials. Rosin mixtures include any of the mixtures of abietic acid with tall oil or tall oil fractions containing various proportions of rosin and fatty acids.

The conditions for disproportionation will be governed by considerations of economy, i.e., conditions effective for reasonably fast rate of disproportionation while avoiding conditions which will cause degradation of the rosin, such as extreme temperatures.

The degree of disproportionation may be controlled as desired and as dictated by the degree of stability required in the end use. Generally, the abietic acid content should be reduced to less than about by weight of the rosin and preferably to the more commercially acceptable level of less than about 5%, same basis. Reduction of abietic acid content can be followed during the reaction by sampling and analysis, employing any of the procedures known in the art such as the Rubber Reserve (ultraviolet) method or, preferably, by gas-liquid chromatography.

EXAMPLES The above-described features of the invention will be more particularly described and illustrated by the following specific examples, many of which constitute preferred embodiments thereof. In order to demonstrate more clearly the application of the inventive principles to tail oil fractions and to rosins and rosin compounds, respectively, the examples dealing with these two classes are arranged in two separate groups and are numbered consecutively within each group.

Group A.-Bleaching and stabilizing tall oil and tall oil fatty acids Examples 1-8 The data reported in Table I was obtained under con ditions substantially as follows:

To a 1000 ml. reaction flask equipped with agitator, thermometer, and gas inlet tube was charged 500 grams of a commercially available tall oil fraction of typical analysis 94.2% mixed saturated and unsaturated fatty acids, 4.2% rosin acids and 1.6% unsaponifiables. Then was added, 2,2-thiobis(4methyl-6-t-butylphenol) in the amounts indicated. A nitrogen atmosphere was then provided and the mixture heated at the indicated temperature for 15 minutes to 2 hours with sampling at 15 minute intervals.

The color scales are based on Gardner 1933 standards wherein the lower the number the lighter the color. Thus 6 is about tea-colored and 1 is pale yellow. The samples were each tested for color stability (stab) by heating Examples 9-10 The thiobisphenol treatment shows good bleaching with substantial stability as compared with the feed. As also shown, further bleaching and stability is achieved by subsequent clay treatment. The colors are based on Gardner 1933 standards.

TAB LE 11 9 10 Example Color Stability Color Stability 7- 8- 8 9- 5 ti G 7* (3laytrcatod. 2+ 4 3 5 Examples l113 Table III demonstrates bleaching, and stabilization of the resulting improved color, of solvent/acid-refined tall oils by treatment at 250 C. under nitrogen with 0.1% by weight of 2,2' thiobis(4-methyl-6-tbutylphenol) for the indicated times essentially as described in Examples 1-8. The tall oils were three grades (Examples 11-13) of Facoil solvent refined tall oils obtained by heating a hexane slurry of crude tall oil with concentrated sulfuric acid and separating the resultant refined oil. The color scale is the same as Examples 18. The color is improved (lightened) by the acid treatment and further improved by the method of the invention as a comparison of the feed color and stability shows.

Examples l416 Under substantially the same conditions as described in Examples l-13 above, good bleaching and stabilization of the resulting color is obtained by treatment of high Group B.Bleaching and stabilizing rosin compounds In all of the examples of this group S-l rosin is tall oil rosin conforming to the Naval Stores Act (February 8, 1952) and Federal Specification LLLR6266, Class C (May 27, 1957). S2 rosin is substantially the same as 3-1 rosin except that it contains less bottoms than S-l rosin. N rosin is an N-colored S-l tall oil rosin and SH rosin is a heat-treated S-l tall oil rosin.

a suitable reaction vessel equipped with thermometer, inert gas inlet and means for agitation. When steam is employed as the inert gas, a suitable condenser is attached. The treating agent is then added to the vessel and heat is applied. The contents are reacted. under an inert gas blanket, such as nitrogen or steam, while maintaining the temperature at a preselected level. Colors are determined following this treatment. Samples are then tested for color stablility after aeration. The samples are aerated by drawing over them for 10 minutes a volume of air equal to 2 milliliters of air per gram of rosin compound which has been heated to 180-200 C. under agitation. The vessel containing the treated rosin compound is then closed and agitation continued for 20 minutes at 180 C. in 200 C. Aeration and color sampling is repeated as required.

Table I below shows a number of runs representing batches of several types of rosin compounds treated as above. For comparison, the results of treatment with several commercially available antioxidants are shown in section 4 of the table.

TABLE I Treatment Color Table Run Type rosin section (batch) compound lemp., Weight, Feed After treating After aeration C. Additive percent 1 hour 18 hours t 2 3 1 1 X WW. ww-wo, WG-N 2 .1 x Y 3A A 3 .4 X 4A 4A A 4 X WW..." WWWCL WG 5 .1 X 3A An-.." 6 .4 4A 2A 7 .1 Y X WW-WG. N 8 WW-WG. WG-N 9 .4 3A X 11 0.1 12 4A 2 13 0.1 5A. 4A 2A 14 0.1 6A 3A 2A 0.05% added at the start of the bleach and 0.05% added after A hour.

In a typical treatment, a rosin compound is charged to Although the non-thiobisphenol sulfur-containing additives show some bleaching, it will be noted that additive I gives a better bleach and less color loss after two aerations than the others. Also notable is the absence of bleaching with additive II which has the same structure as I except that sulfur is replaced by CH Table II below shows the effect of treatment, as in the foregoing runs, on analytical values of S2 tall oil rosin samples. It will be seen that abietic acid content is only slightly reduced and the other values are negligibly affected if at all. Loss of abietic acid, i.e., disproportionation, can be minimized by not heating over 300 C. and by shortening the time of treatment. The analytic methods are those identified or described in Acintol Tall Oil Products, Arizona Chemical Company, New York, November 1964, pages 2326 except that the percent abietic acid is measured by the Rubber Reserve Method and hardness is determined by reading the depth of penetration in 0.1 mm. units of a standard needle into a solid sample, employing a Universal Model Penetrometer.

TABLE 11 'lreating Conditions Analyses Run (batch) Additive, Temp. Time Acid Racine Unsaps, Fatty Specific Hard- S.P., Abietic weight hours number acids percent; acids, rotation uess, C. aci Color percent percent percent mm. percent- 30 (iced) 175. 6 90. 3. 3 4. 0 +4. 1 0. 79. 5 29. 9 X 31 0.1 275 1 174.3 90. 7 4.1 3.1 +15. 5 0.1 83.0 22.1 5A 275 l 174. 8 90. 7 4. 0 3. 3 +8. 3 0. 1 80.0 26. 7 2A 0.1 200 l 175. 3 90. 3 3. 7 3. 9 +11. 9 0. 1 79.0 23. 3 4A 0. 1 240 1 176. 7 89. 4 3.5 5. 5 +7. 4 0.0 81. 0 27. 9 2A Example 2 treating at 275 C. for /1 hour, a color of K resulted.

TABLE III S-1 Rosin S-2 Rosin Color WG'I Percent of WG'I Percent of Additive I Additive 1 Control 0.1 0.4 Control 0.1 0.4

Feed X X X 1 Aeration. WW. X WW WW... X 2 Aerntions... WW-WG- WW X-WW- WW. WW... X 3 Aerations 'G WG... X-WW. WG WW... X

Example 3.Formaldehyde-treated tall oil rosin Part (A). An S-l tall oil rosin sample was first treated with paraformaldehyde in a conventional manner. This product was thereafter bleached as follows:

The formaldehyde-treated rosin was charged to a 1- liter, 3-neck flask with attached agitator, thermometer, gas inlet tube, and condenser. The rosin was heated to 260 C. under a nitrogen blanket and 2,2-thiobis(4-methyl-6-tbutylphenol) was charged to the flask. Heating was continued under steam at 275 C. as indicated with the following results:

TABLE IV Color Additive, 1. percent by weight A [tor blcaclnng- Food )5 hour 1 hour M-N .\l

Part (B).An S-l tall oil rosin, color WW, was charged to a reaction vessel and heated to 275 C. Then 0.02% by weight of 2,2'thiobis(4 methyl 6-t butylphenol) was added and heating was continued for /2 hour. At this time the color was Y. The reaction mixture was then cooled over 40 minutes to 225 C. Color was then 3A. Paraformaldehyde was then introduced at 148 C. and the resulting formaldehyde treated rosin had a color of K.

Part (C).In another run, paraformaldehyde (1 part to 43 parts tall oil rosin) and 2,2-thiobis(-methyl-6-t-butylphenol), 0.02% by weight, were added to 5-1 tall oil rosin, color WW, at 148 C. under pressure. At the end of the formaldehyde treatment, the pressure was vented. A color of 1 (dark) resulted. After heating to 275 C., a color of I (light) was obtained which lightened still further to K when the heating was continued at 275 C. for /2. hour. Cooling was applied and, after 45 minutes, a temperature of 210 C. was reached. A color of M was obtained.

Part (D).The procedure of Part (A) was repeated with 0.02% of the same thiobisphenol additive except that the additive was charged before heating the formaldehydetreated rosin (which had an H color). The mixture was then heated to 275 C. to give a color of I and after Cooling was then applied and, after minutes, a temperature of 210 C. was reached. At this time the color was M.

The foregoing runs show that for good bleaching a somewhat extended heat treatment is required in addition to use of the thiobisphenol additive. The duration of heat treatment will vary according to the temperature. The runs also demonstrate that sequence of formaldehyde treatment and thiobisphenol addition are non-critical with respect to Ibleaching, provided the rosin is heated in the presence of the thiobisphenol, although it is preferred to treat with paraforrnaldehyde prior to bleaching.

Example 4.-Fumaric acid adducts of tall oil rosin Part (A).--In a ]000-ml.. 3-neck flask equipped with agitator, thermometer, gas inlet port and reflux condenser, S-l rosin (color WW) and 4% by weight fumaric acid were heated at -200 C. for 2 hours under nitrogen. A color of N resulted. The resulting rosin was then bleached 30 minutes at 275 C. with 0.1% 2,2-thiobis(4- methyl-6-t-butylphenol). A color of 3A resulted. This color was maintained after an additional 30 minutes treatment at 275 C.

Part (B).-In the same equipment as in Part (A), 8-1 rosin (color WW) was bleached 30 minutes at 275 C. with 0.1% of the same thiobisphenol under nitrogen. A color of 6A resulted. The rosin was then cooled to 200 C. and 4% by weight fumaric acid was added. Treating at 200 C. was continued for 2 hours. After this time, a color of 3A was obtained.

Example 5.Maleic anhydride adducts of tall oil rosin,

In the equipment described in Example 4, S-1 rosin and 3.6% by weight maleic anhydride were heated at 190 C. for 1 hour under nitrogen. A color of M resulted. This adduct was then heated 1 hour at 275 C. with 0.1% 2,2-thiobis(4-methyl-6-t butylphenol), resulting in WG color.

Examples 6-8 TABLE V Color A biotic Ex. A dditive after acid,

treatment percent 6 2,2-thiobis(4411cthyl-ot-butylphenol). 6A 19. 5 7 4,4-thiobis(resorcinol) 5A 18. 4 8 2,2-thiobis(4,trdimethylphenol) 4A 18. 1

Examples 9-10 Essentially as described in Example 1, S2 rosin was treated at 275 C. for 1 hour with 0.1% of the thiobisphenol indicated in Table VI to obtain substantial bleaching as shown. The samples were thereafter cooled to 190- 200 C. and aerated as described in Example 1. These tests show good color stability.

TABLE VI Color Ex. Additive Feed After After aeration bleaching (stability) 1 2 3 9 2,2-thlobls(4,6-dimethylphenol) XWW 6A 4A 3A Y 10 4.4-thiobis(resorcinol) WW 6A A 3A 2A Example 11 about 5 minutes to 5 hours, said phenol sulfide being a A. Preparation of poly[thio(resorcinol)] To a solution of resorcinol in dibutyl ether is slowly added sulfur dichloride. The temperature is held at 10 15 C. for a half hour after the addition and a polymeric black precipitate forms. Sodium hydroxide solution is then added to dissolve the precipitate and the dibutyl ether is stripped by steam distillation. The polymer is thereafter precipated by addition of hydrochloric acid to the residual aqueous phase and is collected by filtration as a material medium tan in color.

The number-average molecular weight is 1250, corresponding to 8 repeating units (p equals 6 in Formula I above) and elemental composition is in the ranges C 4l.58-46.12%, H 2.973.39%, S 21.,3425.06%, ash 324.7%.

B. Bleaching action Essentially as described in Example 1, various samples of S-l tall oil rosin were heated at 275 C. under nitrogen for 30 minutes with 0.02% by weight of the polymeric product of part A above with the good bleaching shown in Table VII below I i TABLE VII Feed color Run Product color 'Ihe color of these products was nearly the same, i.e., product of run 3 was slightly darker than X and the product of run 4 was slightly lighter than WW.

GIT) (HO).. '1 (0B).. (111343-31 {Tr-y) Si]- ]iryl) Rm R p Rm wherein n is an integer from 1 to 3 inclusive, p is an integer from 0 to 100, x is 1 to 3 inclusive, the sum of m and n on each Aryl is from 1 to 5 inclusive. Aryl is phenyl, naphthyl or anthracyl, and R is a hydrocarbon radical of l to 22 carbon atoms, the heating being at a bleaching temperature within the range of about 180 C. to about 350 C. and continuing the heating at said temperature until a substantial lightening in color of the material is obtained but the abietic acid content of any rosin present is not reduced by the heating to less than 15%.

2. The method of claim 1 wherein the phenol sulfide is a poly [thio(resorcinol)] wherein p is in the range of 5 to 20.

3. A method of improving both the color and the color stability of a tall oil containing at least 50% by weight of fatty acids which comprises heating said tall oil at a temperature of about 200 C. to 300 C. in the presence of about 0.01% to 1% of a phenol sulfide for compound of the formula:

wherein n is an integer from 1 to 3, p is an integer from 0 to 100, x is 1 to 3, the sum of m and n on each Aryl is from 1 to 5, Aryl is selected from the group consisting of phenyl, naphthyl and anthracyl, and R is a hydrocarbon radical having 1 to 22 carbon atoms.

4. A tall oil product produced by the process of claim 3.

5. A method of bleaching and stabilizing the color of a material selected from the group consisting of rosin containing atleast 50% of rosin acids and rosin compounds derived therefrom which comprises heating said material in the presence of about 0.01% to 1% of a phenol sulfide of the formula:

wherein n is an integer from 1 to 3 inclusive, p is an integer from 0 to 100, x is 1 to 3 inclusive, the sum of m and n on each Aryl is from 1 to 5 inclusive, Aryl is phenyl, naphthyl or anthracyl, and. R is a hydrocarbon radical of 1 to 22 carbon atoms, the heating being at about 180 C. to 350 C. and for a time ranging from instantaneous to 18 hours and such that a substantial lightening in color of the material. is obtained but the abietic acid content is not reduced by the heating to less than 15%.

6. The method of claim 5 wherein the material is a member of the group consisting of wood rosin, gum rosin and tall oil rosin.

7. A bleached member of the group consisting of wood rosin, gum rosin and tall oil rosin, said member being produced by the process of claim 6.

8. A method of treating a rosin comprising heating said rosin at a temperature of about 180 C. to 350 C. for about 1 to 8 hours in the presence of about 0.01% to 1% of a phenol sulfide of the formula:

wherein n is an integer from 1 to 3; p is an integer from 0 to x is a number from 1 to 3; the sum of m and n on each Aryl is from 1 to 5; Aryl is selected from the group consisting of phenyl, naphthyl, and anthracyl; and R is a hydorcarbon radical containing from 1 to 22 carbon atoms, the heating being for a time such that a substantial lightening of the material is obtained but the abietic acid content is not reduced by the heating to less than 15 9. The product produced by the process of claim 8.

10. The process of claim 8 wherein said phenol sulfide is poly[thio(resorcinol)] wherein p is in the range of 5 to 20.

11. The process of claim 8 wherein said phenol sulfide is 4,4'-thio-bis-(resorcinol).

12. The process of claim 8 wherein said phenol sulfide is 2,2'-thio-bis-(4-methyl-6-t-butyl-phenol).

15 13. A method of improving both the color and the color stability of a tall oil containing at least 50% by weight of fatty acids which comprises heating said tall oil at 200 C. to 300 C. under a blanket of inert gas and at substantially atmospheric pressure in the presence of an effective amount, within the range of about 0.01% to 1%, of a phenol sulfide for a time, within the range of about 5 minutes to 5 hours, until a substantial lightening of its color is obtained, said phenol sulfide being a compound of the formula Rm Rm where n is an integer from 1 to 3 inclusive, p is an integer from 0 to 100, x is 1 to 3, the sum of m and n on each Aryl is from 1 to 5 inclusive, Aryl is phenyl, naphthyl or anthracyl and R is a hydrocarbon radical of 1-22 carbon atoms.

14. A method according to claim 13 in which the tall Oil is a commercial fraction containing about 94.2% mixed saturated and unsaturated fatty acids, about 4.2% rosin acids and 1.6% unsaponifiables, the phenol sulfide is 2,2'-thiobis(4-methyl-6-t-butylphenol), and the heating is at about 240 C. to 275 C. for from about 15 minutes to two hours.

16 References Cited UNITED STATES PATENTS 3,157,517 11/1964 Tholstrup et al 99--163 3,211,794 12/1965 Cofiield 260609 3,253,042 5/1966 Worrel 260-608 3,281,473 10/1966 OShea 260- 609 FOREIGN PATENTS 512,304 4/ 1955 Canada. 294,526 9/1929 Great Britain.

OTHER REFERENCES DONALD E. CZAJA, Primary Examiner. FRED E. MCKELVEY, Assistant Examiner.

U.S. Cl. X.R. l62--180; 26027, 98, 398.5, 609