US2547280A - Cold process for producing an improved soap composition - Google Patents

Description

0R PRODU D P COMPOSITION Fi March 8, 1949 )0 H I5 I6 FATTY ORGANlO ALKAL! ACETK,

ACID ACID METAL ACID April 3, 1951 R. w. PETERSON 2,547,280 T c ggOCES CING AN 12 EMULSION SOLUTION 8 Aengnou SAPONIFICATION 20 1 TREATMENT K comma FOR MARKET ZZ-\ AGTATIDN 4 23 TREATMENT coouue FOR MARKET EQ. Z

INVENTOR. ROY \rJ. PETER$ON BY i a M yM TTORNEYS Patented Apr. 3, 1 951 UNITED. STATES PATENT OFFICE COLD PROCESS FORZPRODUCING A'N IMPROVED SOAP COMPOSITION I R y W- eterson, Fresn a f- Application March 8, 1949," Serial No.'80,154

.- l Claims;

The-presentinventio relates to an improved scap and-a cold-made process for producing. the

soaps are generally produced by-one of three well known processes generally referred to as the ,fullsboiled process, the half-boiled process, and the cold-made process. Each of these processes have their individual. advantages and disadvantages. Explanation of the present invention is facilitated by comparison with well known proc- (ass of soap production. I The full-boil d processis he one most s nelly mpl yed in so p ma in d ons s f faseries of steps including several brine changes, a so-called strong ch ange, and a finishing ehange; Successive steps of boiling are required. "Although the reaction that goes on in saponification'is exothermic, much steam or other source of. 'heat'is'required to raise and to maintain" requisite temperatures. The process not only re- -.quires considerable heat and thus objectionable 11131 expense, butalso demands complex equipinent and apparatus. The temperatures required in forming the soap make the selection of apparatusmaterials of importance in avoiding soap discoloration. The full-boiled process requires a period of time, usually several days, to produce a batch of soap. The advantages of this process are that scraps of soap can be reworked and processed, glycerin can be extracted from the soap; and soaps of various qualities can readily be formed and segregated.

The half -boi1ed process is more economical than the full-boiled process but is productive of inferior soaps and precludes the extraction of glycerin.

'- Th -simplest method of making soap is'the cold-made process. It is distinguished fromthe half-boiled process largely in the matter of temperature. This process, however, requires precise controls. The fats must be purer, the lye of exactly the correct proportion and concentration, and the temperature controls precise. None of the glycerin is recovered in this process, all scrap .soap. must be discarded for no provision is made for reworking the same, and incomplete saponification frequently results in discolored or other defective soap batches; Further, it is difficult to add additional ingredients such as perfume or the like to'soap made. by the cold-.made'prooes becausep ts; Susceptibility tothe breaking of the, emulsi during saponification incident to the introduction of suchadditional materials; and

even the m'qst. careful stirring. Soap. produced .by the. coldemade. process..-nor1nally -.-'must. :age

months before it is sufiiciently' cured-for" the market.

, making of the so called .cold made type obviating the precisetemperature, proportion and concen- ,,tration..requirements heretofore demanded in such a-process.- i Anotherobject is to provide a cold-made process for-making soap that eliminates the waste,

. occasional soap: discoloration and incomplete saponificationcharacteristic of the conventional cold-made-processes.

Another object is to provide for the convenient introduction of perfumes and/or filling .materials in a soap produced by a cold-made process.

Another object is to provide a bar soap of improved physical form conducive to washing ef-' fic-iency and a method of forming'the same economically.

Another object is to provide a soap havingim proved sudsing and cleansing characteristics.

Another object is to provide a soaphaving the aged soap soon after -itsformation,.- A further object is to provide a soap that has iel ii cient cleansing properties'a-nd yet ismild and gentle to the-skin; delicate fabrics, hair, painted surfaces, linoleum-asphalt tile, and other materials on which conventional soaps have adeleterious efiect. v

Still further objects,- and advantages will become apparent in the subsequent description in the-specification.

Referring to the drawing: Fig.- 1 is aqschematic representation, or flow "diagram, illustrative of the soap making process of-thepresentqinvention;

Fig. 2 is= a greatly enlarged-schematic representation oi the soap. structure-of the present invention productive of certain advantages-subse'q'uentlv describech c Referring ins-greater detail to the drawing vIn Figs Lethe; numeral 4 mdesi'gna-tes oleaginous esses.

edissipate. preliminaryv to. agitationuntil a submaterial suitable for making soap of the present invention. Coffee oil, soybean oil, coconut oil, peanut oil, rice oil, animal fat, and any suitable fatty acid may be employed. A source of dilute solutions of water soluble organic acids is represented at H. Acetic acid, oxalic acid, citric acid, tartaric acid and many others are suitable to the purpose. The acids are preferably di-. luted with water, as will subsequently become apparent in the examples, to form weakly aciduous solutions. The fatty acid and the organic acid solutions are mixed, as indicated at l2, to form a fatty acid and a water soluble acid emulsion.

A source of dilute acetic acid is indicated at I 5. The acetic acid is conveniently of approximately five percent (5%) strength in water, such as is found in vinegar. A source of alkali metal, such as sodium hydroxide in commercial lye form, is represented at IS. The acetic acid *solution and the sodium'hydroxide are agitated 'mitted to dissipate its heat generated by the interaction of sodium hydroxide and acetic acid unt l a substantially tepid temperature prevails.

The aciduous-oleaginous emulsion shown at l2 is mixed with the strongly alkaline solut on represented at IT, as shown at l8.-' As is well known in soap making processes, the addition of an alkali metal to a fatty acid results in the saponification of the fatty acid. In the full-boiled process the saponification is carried on at elevated temperatures to obtain improved results and to avoid precise control of purity, proportion and agitation requirements. {made process, the saponiflcation is successfully accomplished only with such precise tempera- In the coldture proportion, and purity control. In the coldmade process, agitation causes the emulsion to break and the entire soap batch is ruined. Preconditioned for saponification by the addition of dilute solutions of water soluble organic acids "to the fatty acids and of a dilute solution of "acet c acid to the a kali metal saponification is carried on without the precise control requirements conventionally known in cold-made proc- This preconditioning not only permits the agitation of the materials during saponification but in the soap of the present invention such agitation conducted in even a relatively violent manner is productive of improved results. The agitation of the fatty-acid-water-so1ublejorganic-acid emulsion and the acetic-acid-alkalimetal solution is represented at l8.

The violence and duration of the agitation performed at l8 are dependent upon the results desired. Normally the mixture is agitated in a mechanical beater for from three to five minutes and the vigor of agitation gradually decreased as the saponifying mixture approaches a homogeneovs and finely textured condition. When "the ag tation is extended for longer periods the saponifying soap becomes crumbly and small quantities of liquor appear. Further, when the agitation is performed in the presence of the exothermic heat incident to saponificatioma stantially tepid condition prevails, a coarser grained crumbly soap results, somewhat similar to that achieved by extended periods of agitation. During the agitation step performed at I8, perfumes, filling materials, and/or other ingredients desired to be incorporated in the finished soap are added.

Sub equent to the agitation at l8, the saponified soap is permitted to cool as represented at IS. The soap resulting at l9 may be finished for commercial use as by cutting and pressing into bars, by grinding into powder or flakes, or by any other appropriate physical or other treatment desired. This finishing step is represented at 20. It has been found convenient when making a powdered soap, to conduct the agitation step [8 as described so as to achieve a crumbly soap. This crumbly soap is readily converted into soap powder by a simple crushing operation, thus inexpensively performing a powdering step conventionally of considerable expense. The crushing is preferably achieved by means of steel rollers between which the soap is forced but may be accomplished in any man ner desired.

It is to be noted that soap produced by the processes described herein is of a quality having all of the attributes attributable to aging of conventional cold-made soap aged for several months promptly upon the completion of the saponification and cooling.

Where it is desired to remix the soap cooled at l9 as to add additional materials or to change the physical condition, the soap is heated slowly as represented at 2| until melted. Subsequent to melting the soap may be stirred, other materials mixed therewith, and-generally treated as the soap was originally treated in the agitation step represented at Hi. This step is schematically represented at 22 and is clearly distinguished fromthe conventional cold-made process in which such operations are not possible."

Subsequent to this second treating of the soap, the same is cooled and permitted to solidify at 23 as originally permitted at l9. This soap resulting at 23 is then finished in any desired manner as at 24. The finishing step 24 can take any of the forms suggested for step 20. The following examples serve to illustrate various embodiments of the present invention. The examples are offered by Way of explanation rather than limitation and it is to be understood that variations in quantities and substitutions of equivalent chemical materials may be accomplished without departing from the spirit or th scope of the present invention.

Example I Coffee oil kilograms 3.0 Commercial lye (94% sodium hydroxide) grams" 504 Water liters 2.0 Acetic acid grams Oxalic acid do 50 Example II Animal fat kilograms --.3;0 Commercial lye (94% sodium hydroxide) grams 515 ,Water liters 2.0 'Acetic acid grams 50 .Qxalic acid do amaze m;

fcihttenzseea n11 mnllhmi nugramsa 3f0 "commercial il'lye 1 (94% TSOdlIlIlTL hydroxide) grams; "564 Water" "liters; 2.0 Acetic-"a 1 "lgrams; 10.0 EUXaIic acid" v. do; 160

v :EwampZeJ-Y- "(iiifie toi-ftl, kilograms 330 iCTommercial lye" '(94 sodium hydroxide) grams; 60 Water do "2E0 fActi acid' -do '46 QX8ij1ii31Gifi.- -'dd; f134 iEmmplvesl i lii'anut OiI1 kilograms 43:0 floznmercial Ilye (9'4 :sodium hydroxide).

'gra'ms 420 Water" v. liters, 1.7 sodiumia'cetate 'grams a v:150 Example .1 1

5011'- kilograms.-- 320 grams; E20- WBKBIYII "lent-em- 1:5 fsodium acetate grams-l; 100 rfiodiimi ioxal'ate.: l melon"- l 150 ampere. i2 iiiimp'fl? kiln ramw' fig 3.ommercial lye 194%?s01dium =.ih'ydroxide')" Water: liters; 220 isodium 'acetate- 'grams I200 sodi 'ummxalate do 200 .:E.ra,mpleIX ix-r-iimal fat ki1ograms 31b Commercial -"1ye (94% sodium hydroxide) grams; 546 'Water liters 2.0 'Gxalic" acid "grams; 134 :Sfidiunliacetate .do' 200 r Example p '55 Animai-iat; ,kilograms "310 water-u -'gra-ms; 486 'iCommercial lye (94% sodium hydroxidelj I do 10'0" G,it1ic:{acid l "litersl 2 Example XI "animal fat r -kilograms 320 "waterpn'; lite'rs 2" 5 Commercial lye (94% sodium hydroxide)" l 7 grams 4'76 "Tartaric acid do 100 Example annnal;rat; l, 'kl'1ojgrams ..3l0 jWater l.. ,r l lit'ers i 12 "Commercial: "lye 1 (94% sodium hydroxide) v r 7 grams; 5I3 Oxalic acid do; '100 Commercial lye "(94% ,orr'the jfattyfacids in emulsion form.

sodium hydroxide) grams 476 Lactic acid do- In the first four examples vthe sodium hydroxide is dissolvedlin a .dilutesolution. of acetic acid Iin water, and. the fatty acid suspended .in emulsion form in a solution of the .oxalicacid and water preliminary to theisapon-ification-steps. It is jtobe understood that various oils and lfats have 'various acidity characteristics and thus theproportions of alkali 'metal required toneutralize' the same will vary somewhat. As isQindi'catedFin Examples '1 te l inclusively, various quantities of acetic acid and oxalic acid may,be-employed. Although there is no precise critical limit to the quantity of Water soluble organic acid employed, it is generally preferable to have the content between one percent (1%) and eight percent L(8%")'b y weight of the soap. Examples 1 to 4 inclusively also demonstrate the balancing of the alkali metal employed with the quantity of fatty acid, oxalic acid, and acetic acid to achieve a neutral *soap', which in'most instances is desired.

As previously'des'cribed, the alkali metal inexcess of that requiredby the acetic acid combines "with the "watersolubleorganic acid to form the alkali metal salt of said metal and acid. It .has been discovered that the reduction of the alkali metalwemployedlanduthe substitution ofthe alkaliametallsaltof lthe water soluble organic acid 'inmthe .fatty .acid emulsion in place lot th-e acid itself achieve comparable results. In Exam- .iple -5, ,the peanut l. oi1..is suspended 'in. emulsion form in a'ldilute solution of sodium-acetate pre-' li'minaryQtoithe saponi-ficationby the sodium hy- .idroxide. It lis to be noted that in- Example .5,

noacetic acid is used with the sodium hydrox- "Ih'is achieves a result superior' to that of the conventional cold-madeprocess for making soapbut .not as good results as the preferred interaction otth'e alkali metal in a solution containing a salt of acetic acid and the alkali metal TIri'EXample 6 the sodium hydroxide dissolved in a dilute solution of sodium acetate andlthe olive oilsuspendcd 'in' emulsion iormlin asdilute 'solution'of .sodium oxalate preliminary to the sapunification. Example '6 achieves results'superior *toExani'ple 5 'and'ithat are comparable :to the results of Examples; to "'4 inclus'iveiy;

spar-nae sified in a dilute solution of oxalic acid prelimi- 'jf nary to saponification. l

Aqueous solutions of acetic acid and water soluble alkali metal salts of acetic acid are most successful as the medium in which the alkali metal may be dissolved preliminary to saponification; However, it is readily demonstrated that other water soluble organic acids and their water soluble alkali metal salts may housed in form- ;ing the-fatty acid emulsions. Examples 10 to 16, both inclusively, demonstrate embodiments of the present invention in which the fatty acids are suspended in dilute solutions of various suitable water soluble organic acids preliminary to saponification. In these examples, the significant step of dissolving the alkali metal in a dilute solution of acetic acid or alkali metal salts of acetic acid has been omitted for purposes of simplicity. In this particular, the soaps resulting from Examples 10 to 16 are not preferred but demonstrate soaps involving certain phases of the present invention having advantages over conventional soaps.

It is obvious that the present invention is not limited to the use of sodium hydroxide as the alkali metal. For example, if potassium hydroxide is employed in place of the sodium hydroxide in Examples 10 to 16, both inclusively, highly satisfactoryw soaps are obtained, In order to "make such soaps, the following quantities 'of potassium hydroxide are substituted for the speci- Grams of Potassium Hydroxide for Specified Sodium Hydroxide Example The broad essence of the present invention is believed to reside in the discoveries that the emulsifying of the fatty acid employed in making soap in a dilute solution of organic acidyor an alkali metal salt of an organic acid achieves the saponification advantages indicated above, that the conducting of the saponification step 'with the alkali metal dissolved in an. aqueous solution of acetic acid or alkali metal salt of acetic acid is advantageous; and that the employment of these two discoveries in the saponification step permits the vigorous agitation of the 'materials during saponifioation achieving a resultant soap having physical properties contributing advantages to the soap not heretofore known "in addition to outstanding chemical ad- {vantages incident to its composition. In Fig. '2 is schematically represented in greatl :magnifiedform, the physical condition of soap produced by the process of the present invention.v Hard, alka li metal soap particles are in- V dicated at 21. The particles are sheathed by thin layers of water soluble salts of the o ganic acids and the alkali metal employed, represented at 28. These layers of soluble salts act much in the manner of mortar in holding the soap particles 21 in bar or flake form. The soap particles are not necessarily spherical and may take various shapes. They are small in size, somewhat dependent upon the agitation conditions as to temperature and violence thereof prevail;- ing during saponification. When the agitation is not unduly long and the agitation is conducted before the exothermic heat of saponification has been dissipated, the particles formed are microscopic in size. When the agitation is conducted for protracted periods and/or at reduced temperatures the particles are somewhat larger, approaching macroscopic in size This is;partic ularly true where the melting and re-agitating steps are employed.

As previously suggested, the soap of the pres ent invention when, agitated under conditions forming relatively large soap particles, may be powdered by a crushing operation. This crushing merely breaks the particles from each other where they have been joined by the salt layers 28. In use the water soluble salt films 28 are readily dissolved releasing the ver fine particles of soap for prompt and effective action. To this phenomena are attributed many of. the superior characteristics of the soap of the present invention relating to speed of sudsing, rate of cleaning,. and the like. The soapis mild and" gentle to the skin, delicatefabrics, hair and other ma.- terials. easily damaged by conventional soaps. To what these gentle characteristics may be at tributed is not definitely known, but it is thought that theymay be. incidentto the sodium oxalate or other water soluble salt of the alkali metal in the resultant soap.

The process of the present invention obviates requirements vfor expensive, elaborate, andcomplex apparatus conventionally required for the productionof high quality soap thus enabling small producers with limited capital to compete with large manufacturers. Upon the completion of the cooling of the soap after saponification, no further ageing is required, the soap at that time possessing the attributes of cold-made soap that has been permitted to age for several months.

The process further obviates the precise temperature, proportion, and concentration requirements heretofore demanded in cold-made processes. Incomplete saponification is completely eliminated and thus this source of waste avoided Scraps of soap normally considered waste may :be reworked. s d s r b d i tan erine w th P1?- erations 2|, 22, and 23 in Fig. 1 and completely utilized. The improvements of the process of L the present invention enable the introduction of perfumes and other materials into soaps made with the simplicity of conventional cold-made processes without the danger of the separation of the emulsion during the addition of such materials.

Although I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limitedt'o' thedtails disclosed herein, but is to be accordedthe full "scope of the claims so as to embrace any and all equivalent Having described my invention, what I claim is new and desire to secure by Letters Patent is:

l. A process for making soap comprising forming an emulsion of oleaginous material in a water soluble organic acid, dissolving sodium hydroxide in a dilute solution of acetic acid to the exhaustion of the acetic acid with an excess of sodium hydroxide, reacting the excess odium hydroxide in the solution on the oleaginous material in the emulsion to saponify the same and on the water soluble organic acid to form a sodium salt of the organic acid, and agitating the solution and emulsion during the saponification of the oleaginous material, said sodium hydroxide being employed in an amount sufiicient to interact with the acetic acid, th weak organic acid of the emulsion, and with the oleaginous material to the substantial exhaustion of said materials.

2. In the cold-made proces of manufacturing soap including the saponification of a fatty acid with an alkali metal hydroxide, a step directed to the preconditioning of the materials employed in said process for saponification comprising the formation of an emulsion of the fatty acid in an aqueous solution of a weak organic acid of low 10 3. In the cold-made process of manufacturing soap including the saponification of a fatty acid with an alkali metal hydroxide, the steps of preconditioning the materials employed in the process for agitation during saponiiication, comprising the formation of an emulsion of the fatty acid in a dilute solution of a Weak organic acid of low molecular weight in water, and the dissolving of ROY W. PETERSON.

REFERENCES orran The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Number

Claims (1)

1. 4. IN A PROCESS FOR MAKING SOAP INCLUDING THE SAPONIFICATION OF A FATTY ACID SOAP STOCK MATERIAL WITH SODIUM HYDROXIDE, THE STEP OF FORMING AN EMULSION OF THE SOAP STOCK MATERIAL IN A DILUTE

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