US2945051A - Metallic salts of commercial stearic acid - Google Patents

Description

July 12, 1960 G. M. DAVIS 2,945,051

METALLIC SALTS OF COMMERCIAL STEARIC ACID Filed Oct. 19, 1955 IN VEN TOR. GERALD M. DAV/5',

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AT TOR/YE X United *itate METALLIC SALTS F (ZOMlVlERCIAL S'IEARIC ACID Gerald M. Davis, Clark Township, Union County, Ni, assignor to American Cyanamid Company, New York, N.Y., a corporation of Maine Filed Oct. 19, 1955, Ser. No. 541,323

4 (Ilaims. (Cl. 260-414) The present invention relates to metallic stearates and more particularly to metallic salts or soaps of higher fatty acids of from about 12 to about 22 carbon atoms, which acids are known and sold in industry as commercial fatty acids and sometimes'as commercial stearic acids. More specifically, the present'inventionrelates to magnesium, calcium and zinc soaps of higher fatty acids which are characterized by a relatively large crystal size. The invention includes the metallic stearate 'compositions and the methods of their preparation.

The greater portion of themetallic stearates of commerce are made from relatively cheap grades of stearic acid which are actually mixtures of higher fatty acids of from about 12 to about 22 carbon atoms and include both saturated and unsaturated acids. The solid acids and the hydrogenated fatty acids represent one group of these commercial fatty acids and normally contain (1) larger proportions of the saturated fatty acids and (2) smaller proportions of the unsaturated acids. This group of acids normally have iodine values of less than 20. On

the other hand, the animal liquid acids, the vegetable liquid acids, the animal fatty acids and the vegetable fatty acids represent another large group of commercial fatty acids which normally contain (1) larger proportions (Sf-unsaturated acids and (2) smaller proportions of saturated acids. 1 The members of this latter group normally have iodine values in excess of 20 and frequently up to as high asabout 160 or more.

Metallic stearates such as zinc stearate prepared from acid mixtures of the former group of fatty acids are frequently used in lacquers, varnishes, printing inks and in surface coating compositions as flattening and sanding sealing agents and to provide covering power. When used for these purposes, a stearate composition having a relatively large average crystal size is preferred, with a minimum of smaller particles or fines of less than 1 micron average diameter. The fiatting and covering efficiency, the sanding sealing properties and the viscosity characteristics of the lacquer would be considerably improved ifzinc stearates having an averagecrystal size on the order of from about 1 to about 7 microns or larger were available .with not more than about 5% by weight having a crystal size of less than about 1 micron. This has been established as desirable inasmuch as zinc stearate crystals in the range of from about 0.1 to about 1 micron in average diameter or slightly larger have been found to give poor flatting and sanding scaling properties and to form a gel in the lacquer, varnish, printing ink, or other material either during grinding or upon subsequent storage.

It is therefore a principal object of the present invention to provide metallic stearate having a relatively large crystal size and possessing improved efliciency as a flatting, covering and sanding sealing agent in surface coating compositions and exhibiting decreased gelling or thickening tendencies during grinding or working or on storage. 7

It has been found that the average crystal size of metallic soaps of commercial stearic acids is materially increased When acids of the first described group are used and when the metallic stearate is formed by a direct reaction of the fatty acids in a molten condition in a sin gle continuous phase with an aqueous slurry of a hydroxide of the particular preferred metal.

Metallic stearates have formerly been prepared normally by reacting the selected fatty acid with an alkali metal hydroxide and then reacting the resulting alkali metal stearate with a metallic salt whereby the metallic stearate, which is formed by metathesis, precipitates out and is separated, filtered, washed and dried.

Other methods have been employed wherein the fatty acids have been present in an emulsified or dispersed condition, such as an aqueous emulsion, and the metallic soap which precipitated out was collected, filtered, washed having relatively small crystal size such as is shown in. T Figure 'l. 'The improved methods of the present invention produce a producthaving a much larger crystal size such as illustrated in Figure 2 of the drawing.

a The improved methods of the present invention are therefore distinguished from the methods of the prior art in (1) the fact that the metallic stearates are formed by a direct reaction of the fatty acids and the hydroxide of the desired metal Without going through any intermediate stages involving the preparation of alkali metal stearates and (2) the fact that the fatty acid mixture is present in a molten condition in a single continuous phase and not in an emulsified or dispersed polyphase system.

In general, an aqueous slurry of the hydroxide is employed and is normally added slowly with gentle agitation to the fatty acid mixture which has previously been heated so that it is in a molten condition.

The molten condition of the fatty acid mixture may be obtained by applying heat directly to the mixture of solid fatty acids until it melts but it is preferred to add the solid fatty acids to water and to heat the same until the fatty acid mixture melts and floats as a single continuous phase or layer on top of the water. I

In the event that a gentle agitation is used during the heating of the fatty acid, such should not be enough to form an emulsion or to intermix the water and the fatty acid to any substantial degree. No emulsion agent should be present which would tend to create e1ther a temporary emulsion or a permanent emulsion.

The slurry of the particular hydroxide is added slowly to the molten fatty acid and the metallic stearate precipitates out in the usual fashion as known in the art and is then separated, filtered, washed and dned by procedures known in the art.

The invention will be further described by reference to the following examples which set forth the specific embodiments of the present invention. These embodiments, however, are merely illustrative and are not to be construed as limitative of the present invention.

Example 1 A sodium stearate soap solution was prepared by adding 127 lbs. of sodium hydroxide to 936 gallons of hot water at a temperature of approximately -75 C. 800 lbs. of.

300 lbs. of zinc sulfate (36% zinc) was dissolved in 2.140 gallons of hot water at a temperature of approximately 6070 C. 1.2 lbs. of concentrated hydrochloric acid (C.P.) was added to this solution which was then dilutedto 2996 gallons for the desired concentration. The pH of this solution was determined to be 3.0.

2322 gallons of hot water at approximately 67 C. was run into a precipitating tank. The sodium stearate soap solution and the zinc sulfate solution were then simultaneously run into the warm water. Measurements of the pH were taken continuously and the pH was controlled to 6.5-6.7. A small amount of zinc sulfate was then added to adjust the final pH to 6.5;

The precipitate of zinc stearate was then separated by a filtering operation wherein the wash water comprised softened water at a temperature above 22 C. The drying took place with air heated to a temperature 103 '105 C.

during the earlier part of. the drying and 100 C. during the later part of the drying.

The final producthas the following analysis:

Moisture per'cent 0.6

Water soluble ash ....do 0.5

ZnO content n do 14.6

Acid No. 1.2 I Percent CaO -1 0.02.

Percent Fe p.p.rn. 30

The. zinc stearate resulting from this method of substantially simultaneously adding the sodium stearate solution. and the zinc sulfate solution was. a relatively fine crystalline product and is illustrated. in Figure 1. Such a product was" satisfactorily used as a' mold lubricant but was not acceptable as a flatting or sanding sealing agent.

Example 2 400 grams of Zinc sulfate (ZnSO -H O) was dissolved in 2000 grams of water at room temperature. 179.5 grams of 100% sodium hydroxide (dissolved) was added to the Zinc sulfate solution with slow agitation.

100 grams of Hyfac 400 (a hydrogenated fatty acid of a relatively cheap rubber grade having high color (70Y/14R-5.25 SC.) and containing 1% lauric acid, 3% myristie acid, 28% palmitic acid, 63% stearic acid and.5% oleic acid) (Iodine valueWijs) was melted in 16,000grams of hot water maintained at a temperature.

between65 and 70 C. Slow agitation was used and was not sufiiciently strong as to emulsify or disperse the fatty acid which remained for the most part in a separate layer distinct from the hot water. layer.

The zinc hydroxide slurry formed by the reaction of the zinc sulfate and the sodium hydroxide was then added to the melted fatty acid with slow agitation and the temperature was maintained between 65 and 70 C. The zinc stearate precipitated out, was separated and filtered, washed and then dried at a temperature of about 100 to 105 C. for about 45 minutes.

The resulting zinc stearate had the following properties:

15.68% total ash 15.28% washed ash 0.40% water soluble ash 1.43% moisture and volatile matter at 105 C. 7.45 apparent density (lbs/cu. ft.)

1.68 acid value (mgm. KOH) 6000 film area (sq. cm./g.)

The zinc stearate resulting from this method of preparation was a relatively coarse crystalline product and is illustrated in Figure 2. Such a product was satisfactorily used asa fi'atting and sanding sealing agent.

Example 3 200 grams of Zinc sulfate (ZnSO -H O) was dissolved in 1200 grams of'water at room temperature. 85 grams of 100% sodium hydroxide (dissolved)'was added to the zinc sulfate solutionwith slow agitation.

500 grams of Hy-fac 410 (a hydrogenated tallow fatty acid having a lower col'or' ('30Y/5R5.25" S.C.)" than Hyfac 400 and containing 1% lauric acid, 3% myristic acid, 28% palmitic acid, 63% stearic acid and 5% oleic acid) (Iodine value-7) was melted in 16,000 grams of hot water maintained at a temperature between 65 and 70 C. Slow agitation was used' and was not sufficiently strong as to emulsify or disperse the fattyacid which remained for the most part in. av separate layer distinct from the hot water layer.

The zinc hydroxide slurry formed by the reaction of the Zinc sulfate and the sodium hydroxide was? then added to the melted fatty acid with slow agitation and the temperature. was maintained. between 65 and 70 C. The zinc stearate precipitated out, was separated and filtered, washed and then dried at a temperature of about 100 to 105 C. for about 45 minutes.

The resulting zinc stearate had the following properties:

15.48% total ash 15.10% washed ash 0.38% water soluble. ash n 0.80% moisture .andlvolatile. matter at 105 C.

' 8.0 apparent density '(lbs.[cu. ft.) 7

0.84, acid value (mgm- .KOH)f 5250 film area (so. cmi/gdj Thezinc stearateresulting fromlthis methodof preparation was arelatively coarse: crystalline product and was approximately similar: iirsize-to the crystals illustrated in Figure 2. (Majority of crystalsbetweenl and 7-microns.) Such a; product: was. satisfactorily used as w flatting and sanding sealing agent.

Example74 200 grams of zinc sulfate (ZnSO -H O) was dissolved in 1200 grams of water at room temperature. grams of sodium hydroxidev (dissolved) was added to the zinc sulfate. solution. with slowagitation.

500 grams of Hyfac 420 (a: hydrogenated tal'low fatty acid havinga color 4Y/0.4R- -5.25" SC. and containing 3% myn'stic acid, 29% palmitic. acid, 65% stearic acid and 3% oleic acid) (Iodine. value 3.). was' melted in 16,000 grams of hot water maintainedata-temperature between 65 and- 70- (3. Slowagitation was used and was not sufficiently strong as to:- ernulsify the fatty acid which remainedfor' the most part in-a separate-layerdistinct fromthe hot water. layer.

The zinc' hydroxide slurry formed. from; thereaction of the zinc sulfate and the sodium: hydroxide was then added to the-melted: fatty acid. and the temperature was maintained between. 65 and 70 C. The zinc st'earate precipitated out,.was separated and filtered,.washed and then dried at a temperature of: about 100 to C. for. about 45 minutes.

The resultingzinc stearate hadthe following properties:

15.75% total ash 15.20% washed ash" 0.55% water soluble ash 1.08% moisture and volatile matter'at' 105 C. 8.4 apparent density (lbs/cu. fti)" 1120 acid value (mgm. KOH

5500 film area ("sqi omz/ g.)

grams'of 100% sodium hydroxide was then added to the hot fatty acid and zinc sulfate mixture.

The zinc stearate precipitated out, was separated and filtered, washed and then dried at a temperature of about 100 to 105 C. for about 45 minutes.

The resulting zinc stearate had the following properties:

The zinc stearate resulting from this method of preparation was a relatively coarse crystalline product having a particle size ranging from. about 1 micron up to about 7 microns with less than by weight less than about 1 micron.

Example 6 200 grams of zinc sulfate (ZnSO -H O) was dissolved in 1200 grams of water at room temperature. 85 grams of 100% sodium hydroxide (dissolved) was added to the zinc sulfate solution with slow agitation.

. 500 grams of Hyfac 430 (a hydrogenated fish oil fatty acid containing 4% myristic'acid, 32% palmitic acid, 22% stearic acid, 23% arachidic acid, 13% behenic acid and 6% oleic acid) (Iodine value-) was melted in 16,000 grams of hotwater maintained at a temperature between 65 and 70 C. Slow agitation was used and was not sufficiently strong as to emulsify the fatty acid which remained for the most part in a separate layer distinct from the hot water layer.

The zinc hydroxide slurry formed from-the reaction of the zinc sulfate and the sodium hydroxide was then added to the melted fatty acid with slow agitation and the temperature wasmaintained between 65 and 70 C. The zinc stearate precipitated out, was separated and filtered, washed and then dried at a temperature of about 100 to 105 C. for about 45 minutes.

The resulting zincstearate had the following properties:

17.88% total ash 14.80% washed ash 3.08% water soluble ash 0.50% moisture and volatile matter at 105 C. 8.0 apparent density (lbs./ cu. ft.)

1.68 acid value (mg-m. KOH) 5250 film area (sq. cm./g.)

Example 7 400 grams of zinc sulfate (ZnSO -H O) was dissolved in 2000 grams of water at room temperature. 180 grams of 100% sodium hydroxide (dissolved) was added to the zinc sulfate solutionwith slow agitation.

1000 grams of Emersol 110 (a single-pressed fatty acid containing 2% myristic acid, 48% palmitic acid, 39% stearic acid, 10% oleic acid and 1% linoleic with an Iodine value of was melted in 16,000 grams of hot water maintained at a temperature between 65 and 70 C. Slow agitation was used and was not sufliciently strong as to emulsify the fatty acid which remained for the most part in a separate layer distinct from the hot water layer.

The zinc hydroxide slurry formed from the reaction of the zinc sulfate and the sodium hydroxide. wasthen added to the melted fatty acid with gentle agitation'and.

the temperature was maintained betwecn'65 and 70 C.

tered, washed and then dried at a temperature of about to C. for about 45 minutes.

The resulting zinc stearate had the following properties:

7 15.88% total ash 15.38% washed ash 0.50% water soluble ash 1.30% moisture and volatile matter at 105 C. 7.4 apparent density (lbs./cu. ft.)

1.68 acid value (mgm. KOH) 6000 film area (sq. cm./g.)

The zinc stearate resulting from this method of preparation was a relatively coarse crystalline product and is illustrated in Figure 2. Such a product was satisfactorily used as a flatting and sanding sealing agent.

Example 8 grams of calcium chloride (CaCI -H O) was dissolved in 1200 grams of water at room temperature. 93 grams of 100% sodium hydroxide (dissolved) was added to the calcium chloride solution with slow agitation.

600 grams of Hyfac 400 was melted in16,000 grams of hot water at a temperature maintained between 65 and 70 C. Slow agitation was used which was not sufficiently strong as to emulsify or disperse the fatty acid which remained for the most part in a separate layer distinct from the hot water layer. 1

The calcium hydroxide slurry formed by the reaction of the calcium chloride of the sodium hydroxide was then added with slow agitation to the melted fatty acidand The calcium stearate resulting from this method of precipitation was a relatively coarse crystalline producthaving a particle size which was well above an average of 1' micron, with several particles being noted as about 7-8 microns across. Such a product was satisfactorily used in waterproofing compositions wherein the larger plate-like crystals provided for more even spreading. The product showed no tendencies to form a gel in coating material either during grinding or upon subsequent storage.

Example 9 165 grams of calcium chloride cacn-n o and 600 grams of Hyfac 410 were dissolved in 16,000 grams of water at a temperature of about 6570 C. 93 grams of 100% sodium hydroxide (dissolved) was added to the mixture with slow agitation. The calcium stearate precipitated out, was separated and filtered, washed, then dried at a temperature of about 100 to 105 C. for about 45 minutes. l V The resulting calcium stearate had the following properties:

7.28% total-ash 7.20% washed ash 0.08% water soluble ash 2.5% moisture and volatile matter at 105 C. 7.5 apparent density (lbs. per cu. ft.)

1.56 acid value (mgm. KOH) Percent chlorideslight trace The-calcium stearate resulting from this method of 7 precipitation-was a. relatively. coarse crystalline...product v and is similar to that; illustrated; inFigure 2;. Such; a. product. was; satisfactorily used. in. coating; compositions and. showed no tendencies to form a gel either during grinding or upon subsequent storage.

Example 10 165 grams of calcium chloride; (CaGlz'HgQl-was dissolved in 1200 grams of water. at'room temperature. 93 grams of 100% sodium hydroxide (dissolved) was. added to the calcium chloride solution with slow agitation.

600-grams of Emersol 130 (a triple-pressed fatty acid containing 1% myristic acid; 50% palmitic acid, 47% stearic acidand 2% oleic acid) was melted in 16,000 grams of hot water at a temperature maintained between 65 and 70 C. Slow agitation-was used which was not sufficiently, strongas to emulsify or disperse the fatty acid which remained'for the most part in a separate layer distinct. from the hot .water layer.

The calcium hydroxide formed. by the, reaction of the calcium chloride of the sodium hydroxide was then added to the melted fatty acid and the temperature was maintained between 65 and 70 C. The addition is made slowly With' slow. agitation. The calcium stearate precipitated out," was separated and filtered, washed andthen dried at aternperature of about 100 to 105 C. for about 45 minutes. v

The resultingcalcium stearate had the following properties:

9.55 total ash 9.50% washed ash 0.05% Water soluble ash 2.3%moisture and volatile matter at 105 C. 7.4 apparent density (lbs. per cu. ft.) 1

1.12 :acid value .(mgm. KOH) Percent chlorideslight trace The calcium stearate resulting from, this method of precipitation was relatively coarse crystalline product and was satisfactorily used in coating compositions.w It possessed excellent coveringpower and showed no gelling or thickening action.

Example. 11.

100 grams-of hydrated-lime wasdissolved in 1200 grams of hot water atabout 65 70 0.

600*grams-of Hyfac 420was'melted in 16,000 grams of hot Water at a-temperature maintained between 65 and-70 C. Slow agitation was -usedwhich was not sufficiently strongasto emulsify or disperse the fatty acid which remained for the most part in a separate layer distinct-fromthe hot water layer.

The-lime slurry was then-slowly with gentle agitation added to the melted fatty acid and the temperature was maintained between 65 and 70 C. The calcium stearate. precipitated out, was .sep arated andfiltered and then dried at..a.temperature.of about 10.0 to 105 C. for about 45 minutes.

The resulting calcium stearate. had the following, properties:

10:65 total ash 10;60%* washed ash 0.05% watersoluble ash 1.95% moisture and volatile matter at 105 C. 10.0 apparent density (lbs. per cu. ft.)

2.24 acid value (mgm. KOH) Percent chlorideslight trace The calcium. stearate, resulting from this method .of precipitation was a relatively coarse crystalline product having a particle size whichwas well. abovean average-- diameter of 1 micron, with several. particles being noted as about 7-8 microns diameter. Such a product was satisfactorily used. in agwaterproofing composition and showed 2 no -.tendenciesvto; tormia; gel either. durinecr n ineor upon subsequent storage;

Example 12 100 grams of hydrated,limerwaaaddedrto l6;000"grams- 01": water at, 65-70. 6. temperature. v

600 grams of Hyfac 430 was melted and added slowly to the dilute lime slurry with slow agitation:

The calcium stearate precipitated out, was separated and filtered and then dried at a temperature-of about 100 to 105 C. for about -mi-nutes;

The resulting calcium stearate hadthe" following properties:

10.80% total ash 10.70% washedash 0.10% water soluble ash V 2.63% moisture and volatile mattenat 105 C. 13.50 apparent density (lbs. per cu.-ft';--)"

7.00 acid value (mgm. KOH) 0.05 chlorides Thecalcium stearate resulting fromthis method-ofprecipitation-was arelatively coarse crystalline product andwas used satisfactorily'in waterproofing-paper, textiles,

cordage, wood, cement, plaster, asbestos, I'OCKWOOI, and-- 'various building materials. It showed-no' -tendencies to form a gel or thicken: eith'erduring: grinding or--upon subsequent storage. 7

Example 13 gentle agitation to the melted fatty acid and the temperature was maintained about C. Themagnesiumhydroxide precipitated out, was separatedandfiltered, washed and then dried at a temperatureof-'about-75' C. for about 15 hours.

The resulting magnesium stearate properties:

8.02% total ash 6.88% washed ashi 1.14% water soluble'ash 0.65% moistureand volatilematterat.1059 CI. 4.06 acid value (mg-m. KOH) The magnesium stearate resulting from this method 'of preparation was a relatively coarse crystalline product and apparently existed in plate-like structures having less of a tendency to ball up,gel or thicken.

Although I have described-but a-fewspecific examples of my inventive concept, I" consider the same-not to be limited thereby nor to the specific-substances mentioned therein, but to include :various other compounds of equivhad' the-following;

alent constitution as set forth intheclaims-appended hereto. It is to be understood, of course; that-any suit-- able changes, modifications and variations may be made without departing from the scope and spirit-"of the -invention. V Y

What I claim is:

1. A: method of producing-a coarsely crystalline me tallic soap composition having an average crystali-siz'e of from about 1 to 7 microns in diameterwith not more than-5% less than-1 micron. in diameter -from a mixtu-re of: commercial fatty acids of= frorn-l2 to 22*carbon: atomscontaining less than 20% by weight of unsaturated fatty acids and. having .an iodine value ofdess than:20fwhiohi comprises supporting 'a continuous phase layer of said mixture of fatty acids in molten condition on an underlying body of a hot aqueous liquid, reacting therewith an aqueous slurry of a hydroxide of a metal from the group consisting of magnesium, calcium and zinc while maintaining the fatty acid layer distinct from the underlying aqueous layer and thereby precipitating a soap of said metal and said mixture of fatty acids and washing and drying the soap so produced.

2. A method of producing a coarsely crystalline zinc soap composition having an average crystal size of from about 1 to 7 microns in diameter with not more than less than 1 micron in diameter from a mixture of com! mercial fatty acids of from 12 to 22 carbon atoms con-- taining less than 20% by weight of unsaturated fatty acids and having an iodine value of less than 20 which comprises supporting a continuous phase layer of said mixture of fatty acids in molten condition on an underlying body of a hot aqueous liquid, reacting therewith an aqueous slurry of zinc hydroxide while maintaining the fatty acid layer distinct from the underlying aqueous layer and thereby precipitating the zinc soap of said mixture of fatty acids and Washing and drying the soap so produced.

3. A coarsely crystalline metallic soap selected from the group consisting of the magnesium, calcium and zinc soaps of commercial fatty acids of from 12 to 22 carbon atoms containing less than 20% by weight of unsaturated fatty acids and having an iodine value of less than 20, said soap being characterized by an average crystal size of from about .1 to about 7 microns in diameter with not more than about 5% by weight having diameters less than 1 micron and by an absence of gel-forming tendencies in coating compositions.

4. A coarsely crystalline zinc soap of a mixture of commercial fatty acids of from 12 to 22 carbon atoms containing less than 20% of unsaturated fatty acids and having an iodine value of less than 20, said soap being characterized by an average crystal size of from about 1 to about 7 microns in diameter with not more than 5% by weight having diameters less than 1 micron and by an absence of gel-forming tendencies when the soap is incorporated into a surface coating composition.

References Cited in the file of this patent UNITED STATES PATENTS 2,466,925 Brauner Apr. 12, 1949 2,650,932 Kebrick Sept. 1, 1953 2,809,121 Davis et a1. Oct. 8, 1957 OTHER REFERENCES Fisher: Soaps and Proteins, 1921, pages 10 and 26.

Claims (1)

1. A METHOD OF PRODUCING A COARSELY CRYSTALLINE METALLIC SOAP COMPOSITION HAVING AN AVERAGE CRYSTAL SIZE OF FROM ABOUT 1 TO 7 MICRONS IN A DIAMETER WITH NOT MORE THAN 5% LESS THAN 1 MICRON IN A DIAMETER FROM A MIXTURE OF COMMERCIAL FATTY ACIDS OF FROM 12 TO 22 CARBON ATOMS CONTAINING LESS THAN 20% BY WEIGHT OF UNSATURATED FATTY ACIDS AND HAVING AN IODINE VALUE OF LESS THAN 20 WHICH COMPRISES SUPPORTING A CONTINUOUS PHASE LAYER OF SAID MIXTURE OF FATTY ACIDS IN MOLTEN CONDITION ON AN UNDERLYING BODY A HOT AQUEOUS LIQUID, REACTING THEREWITH AN AQUEOUS SLURRY OF A HYDROXIDE OF A METAL FROM THE GROUP CONSISTING OF MAGNESIUM, CALCIUM AND ZINC WHILE MAINTAINING THE FATTY ACID LAYER DISTINCT FROM THE UNDERLYING AQUEOUS LAYER AND THEREBY PRECIPITATING A SOAP OF SAID METAL AND SAID MIXTURE OF FATTY ACIDS AND WASHING AND DRYING THE SOAP SO PRODUCED.

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