Патент USA US2411443код для вставки
Patented Nov. 19, 1946 2,11,443 UNITED STATES PATENT OFFICE’ Lyle J. Lofdahl, Chicago, 111., assignor to Indus trial Patents Corporati0n,.Chicago, 111., a cor poration of Delaware ' No Drawing. Application May 1, 1944, Serial No. 533,645 10 Claims. (Cl. 260-3985) 1 2 The present invention relates to the improve ment of soaps and, more speci?cally, it is con cerned with the manufacture of soap composi tions having improved resistance to discolora Generally speaking, the agent may be employed in the proportion of from about 0.003 per cent- to tion and rancidi?cation. . The deterioration of color and odor in soaps is generally attributable, either directly or indi rectly, to autoxidation of unsaturated fatty acid radicals contained in the products in various per 2 per cent based on the weight of the resulting soap product. The upper limit will, in most cases, be governed by economical considerations, whereas the lower limit will depend upon the proportion of unsaturated functions in the raw material. It is preferred to employ from about 0.1 per cent to about 1 ‘per cent of the agent to centages. The oxidative process is, furthermore, 10 provide a satisfactory stabilizing action for most greatly accelerated in the ‘presence of certain purposes. It is obvious, however, that very small metals which apparently catalyze the oXidative amounts of the agent are required in the case of reaction. Since hydrogenating the unsaturated soaps made from partially or fully hydrogenated functions in the soap stock greatly increases the fats and tallow. On the other hand, amounts in cost and tends to reduce the desirable solubility 15 excess of about 1 per cent may be desired in the of the product, this method of achieving sta case of highly unsaturated soaps. 7 bility has not proven to be entirely satisfactory. The agent may be prepared by ?rst stirring The incorporation of certain types of tin com powdered borax into an aqueous solution of stan pounds, including sodium stannate, sodium stan nic chloride until the mixture has been raised nite, alpha stannic acid, and others, has been 20 to a pH value of from about 4 to 6. ‘ proposed in the prior art as a means for inhibit ing the chemical processes resulting in rancidi ?cation and discoloration of soap. Although a number of these derivatives inhibit rancidi?ca The mixture is continuously stirred until it as tion for satisfactory periods of time, preliminary 25 sumes a gel-like condition and, preferably, the discoloration has been found to occur prior to pH adjusted to about neutral. The gel product odor rancidi?cation. The main object of the invention is to improve the resistance of manufactured soaps to discolor ation. ’ _ _ Another object is to satisfactorily inhibit dis coloration and rancidi?cation in soap products while, at the same time, preserving‘ the fresh soap contains about 30 per cent solids and is ready for incorporation into'the soap. The stannic borate gel formed by the above 30 procedure or stannic borate per se may be added to the soap or soap product at any convenient point in the manufacturing‘ operation. For ex ample, it has been found advantageous to incor odor for an inde?nite_period. porate the agent into‘ the soap stock while in the The invention contemplates stabilizing soap by 35 kettle or the crutcher, prior to‘ framing or before the incorporation of stannic borate therein. It the drying operation. In the case of a toilet soap, has been discovered that when this compound is it may be added before, after, or during the mill incorporated into the soap during the process of ing operation, with or without coloring matter, manufacture, it is possible to accomplish a sub perfumes, fillers and the like. The addition of » stantial improvement in the prediscoloration pe 40 the agent is preferably accomplished as soon as riod of the resulting soap composition. Further possible after saponi?cation so as to curtail the more, a substantial extension of the prerancid formation of intermediate peroxides. As a gen i?cation period over that possible in the use of eral rule, the sooner the antioxidant can be added other tin compounds as inhibitors is obtained. to the soap stock, the more effective the stabiliz Preferably the invention is carried out by incor 45 ing action. porating the reaction product of an aqueous In order to obtain a comparison between the solution of stannic chloride and borax, having a effect of stannic ‘borate with known inhibitors on substantially neutral pH, into the soap» stock lengthening the prediscoloration period of soap during the process of manufacture. The ad products, a number of samples were prepared vantage of adding the agent in this form is that 50 from the same lot of soap containing the same substantially improved dispersion results due to amount‘ of stabilizer (0.05 per cent) and the the colloidal condition of the reaction product. samples subjected to aging treatments to deter The amount of the agent to be added is de mine the relative deterioration that had occurred pendent on the degree of unsaturation of the raw during the respective periods. At the termina materials, e. g. fat, in a particular instance. 55 tion of the test period, color readings were taken 2,411,449 3 on the aged samples, using a Zeiss Pulfrich alpha stannic acid, stannous chloride and other Photometer which measures the whiteness of the acid-forming salts which have at least a mild sample in comparison with a pure white block corrosive action on metallic surfaces. of baryta white. A reading of 100 on this instru It is obvious that the proportions of the agent ment indicated a material which is pure white. U! employed may be varied over wide limits without In the following table, the control indicates departing from the spirit of the invention. More samples. which did not contain any- stabilizer, over, the speci?c manner described herein for in while the color of the fresh samples prior to sub corporating the agent into the soap stock is purely jection to the aging tests are indicated in the last column. for the purpose of illustration and is not intended as limiting the invention. I claim: 1. The method of stabilizing soap, which com Aged - Alpha Sodium Sodium sggggéc stannic stanacid nate stsnnito Chg; _ Color of fresh sample I. Six months at room con ditions _____ ._ 56. 2 49. 5 _______________ __ 43. 7 70. 0 43. 6 70.0 3. The method of improving the color stability 79. 8 20 of soap, which comprises incorporating therein II. Six months porating therein a small amount of stannic borate. at room con ditions _____ __ 59.0 ______ -_ 55.3 73. S ______ __ 55. 1 51.7 111. Two weeks at 45° C ____ s. - prises incorporating therein stannic borate in suf?cient amount to substantially retard de 15 terioration and color formation. 2. The method of improving the color stability of a soap composition, which comprises incor ______________ _- during the process of manufacture the reaction product of an aqueous solution of stannic chloride In Experiment I, the effect of stannic borate is . and borax, having a substantially neutral pH, compared with that of alpha stannic acid in a said product comprising as an essential ingredient milled soap by aging both samples for 6 months at room conditions. As shown in the table, the 25 stannic borate. 4. The method of stabilizing soap, comprising sample containing stannic borate showed a ma incorporating therein from about 0.003 per cent terial improvement in color over the sample con to about 2 per cent of stannic borate. taining alpha stannic acid. Experiment II sim 5. The method of stabilizing soap, comprising ilarly demonstrates the superiority of stannic boram over sodium stannate and sodium stannite 30 incorporating therein between about 0.1 per cent and about 1 per cent of stannic borate. in samples taken from another soap lot. In 6. A color stable soap product, comprising a Experiment III, the eifect of stannic borate on body of soap and stannic borate uniformly dis the prediscoloration period of framed soap is persed through said body in su?icient amount to compared with sodium stannate. In this case, the stabilize substantially the soap against deteriora samples Were given an accelerated aging test by tion and color formation. maintaining them at 45° C. for 2 weeks. It was '7. A stable soap product, comprising soap and observed that the sample containing stannic bor a small amount of stannic borate stabilizer in ate showed a very marked improvement in color corporated therein. and odor over the sample containing sodium 8. A stable soap product comprising soap and stannate. In Examples 1 and 2, the agents were 40 added during amalgamation and prior to milling, between about 0.003 per cent to about 2 per cent while in Example 3, the agents were added during of stannic borate incorporated therein to stabilize the crutching stage of processing. the color. A soap stock consisting of 83 per cent tallow 9. A stable soap product comprising soap and soap and 17 per cent coconut soap has been 45 between about 0.1 per cent to about 1 per cent of stabilized with 0.2 per cent of a reaction product stannic borate incorporated therein to retard de of an aqueous solution of stannic chloride and terioration and color formation. borax, while being processed in the crutcher. 10. A stable soap product comprising soap and The stabilized soap product maintained substan a small amount of the reaction product of an tially the original color for an inde?nite period aqueous solution of stannic chloride and borax of time. incorporated therein to retard deterioration and An outstanding advantage is that stannic borate color formation, said product comprising essen is a neutral product and, therefore, entirely free tially stannic borate. from any corrosive action on soap making equip ment. In this respect, the agent is superior to LYLE J. LOFDAI-IL.