US2388767A - Soap composition - Google Patents

Description

Patented Nov. 13, 1945 2,388,767 soar oom'osrrron Leopold Sai'rin, Philadelphia, l'a., asslgnor to Wilson 8; 00., Inc., a corporation of Delaware No Drawing. Application April 1, 1943, Serial No. 481,458

8 Claims. (01. 252-121) This invention relates to improved soap comtion of a high quality toilet soap having a high sudsing rate from fats and oils substantially free from low carbon chain fatty acids, especially lauric acid.

In the preparation of a high quality toilet soap in accordance with prior art methods it is the usual practice to incorporate into the soap stock a substantial percentage, from about 10 to 30%, of fats and oils containing a high percentage of low carbon chain fatty acids rich in lauric acid such as cocoanut oil, babassu oil and palm kernel oil to enhance the lathering and sudsing properties of the soap, particularly in cold and hard water. The presence of these low carbon chain fatty acids, in the amounts normally used, is objectionable because they not infrequently irritate the skin of some users. Nonetheless, their use has been quite prevalent because of the difliculty and cost involved in producing a highgrade soap, which lathers and foams well in cold and hard water, from soap base, such as tallow stock, palm oil, olive oil, or other animal and vegetable fats and oils, free from substantial percentages of low carbon chain fatty acids.

The use of surface active agents to enhance the lathering and sudsing properties of high carbon chain fatty acid soaps such as tallow base soaps is, of course, well-known; however, their use in the preparation of a high grade toilet soap has not been satisfactory because either the resulting soap was of an inferior quality, or too costly because of the need of a relatively large amount of the surface active agent.

Some of these prior art surface active agents are effective to improve the lathering and sudsing properties of a soap made from tallow stock, for example, and at the same time make possible the formation of a fair grade of toilet soap, but it is necessary to use as much as about 40 to 50% of the commercially available surface active agent with respect to the soap stock to obtain a satisfactory soap, thereby substantially adding to the cost. In substantially lesser amounts, say about 2% and less, these surface active agents are ineffective and, for all practical purposes, use-- less. The hydrocarbon sulfonates now commercially available are entirely unsuitable for use in the preparation of a high quality toilet soap, regardless of the amount used. Others of these prior art surface active agents are active only in conjunction with inorganic alkaline or neutral salts and must be used in amounts of at least 5% in order to improve the foaming and sudsing properties of a tallow base soap, for example. to any substantial extent. The resulting compositions are good detergent compositions, but are entirely unsuitable as high grade toilet soaps. These salt-containing detergent compositions, in soap cake form, tend to crack and have a harsh action on the skin, due largely to the presence of the salts. In addition, the introduction of the salt into the soap composition undergoing processing introduces considerable technical difliculties, particularly during the milling operation.

In accordance with the present invention I have made high grade toilet soaps having superior foaming and sudsing properties from tallow stock and other high carbon chain fatty acid stocks or mixtures of high carbon chain fatty acid stocks by incorporating into these stocks or into the saponifled stocks before final soap formation, small amounts of a specially prepared and purified surface active agent and rosin, preferably hydrogenated rosin. The surface active agent in accordance with the present invention is a purifled, substantially salt-free alkali sulfonate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons of 12 to 14 carbon atoms in the molecules. The crude mixture, from which this purified, substantially salt-free agent is obtained as hereinafter described, may be made, for example, in accordance with the methods described in the Henke and Lockwood United States Patent No. 2,197,800, granted April 23, 1940.

The quantity of purified, substantially saltfree surface active agent used in accordance with the present invention need be no more than about 1% to 1 and may be less, say about of 1% or even as little as of 1% by weight of the finished soap. As for the rosin or hydrogenated rosin, the quantity may vary from about 1 to 5%, preferably about 3 to 5% by weight of the soap. Slightly larger and lesser amounts may, of course, be used, but optimum results are obtained with an amount of rosin or hydrogenated rosin in the order of about 3% to about 5%. Amounts of rosin or hydrogenated rosin substantially above about 5% reduce, the quality of the soap.

The combination of the purified, substantially salt-free surface active agent in accordance with the present invention and 0f the rosin or hydrogenated rosin in a high carbon chain fatty acid soap results in the formation of a high grade toilet soap having superior foaming and sudsing properties in both cold and hard water. Moreover, the soap in accordance with the present invention has no irritating action on the skin, even of persons normally allergic to soaps. The foam from the soaps of my invention is abundant, rich and free lathering, although different from that of soaps made from stock containing oils rich in lauric acid.

The combination of the purified, substantially salt-free surface active agent and the hydrogenated rosin in a tallow base or like soap not only increases the solubility of these soaps, but decreases their normal sensitivity to hard water and changes essentially their foaming and sudsing properties. I am not prepared to state the reason for this, but it appears that the purified, substantially salt-free surface active agent in combination with the hydrogenated rosin has a specific promoting and activating action on tallow base soaps and other high carbon chain fatty acid soaps substantially free from low carbon chain fatty acids such as lauric acid. When tested in accordance with standard methods, the foaming and sudsing properties of the soaps of the present invention are greater by far than are those of tallow or like soaps containing only the purified substantially salt-free surface active agent or only the rosin or hydrogenated rosin in the amounts used in accordance with the present invention, the effect of the combination on tallow and like high carbon chain fatty acid soaps is synergistic.

The purified, substantially salt-free surface active agent in accordance with the present invention is prepared by treating a crude mixture of sulfonated hydrocarbons having a predominant portion of straight chain saturated hydrocarbons of 12 to 14 carbon atoms of the following general specifications Active ingredients per cent About 50 Salt do 3 to 6 Not reacted oil do Less than 5 Color Light brown In carrying out the refining treatment in accordance with the present invention, 1 part by weight of the crude mixture of the above described surface active agent, for example, is mixed with about 3 to 5 parts by weight of a fatty acid or its equivalent such as oleic acid, tallow fatty acids and abietic acid, normal or hydrogenated, to separate the salt, water and other impurities from the active ingredients. Rosin or hydrogenated rosin itself may be similarly used, and I prefer to use them rather than the free acids to effect refining because the rosin or hydrogenated rosin is used as a constituent of my soap along with the refined agent. For example, 1 part by weight of the crude mixture of the surface active agent is mixed with 3 parts by weight of hydrogenated rosin and the mixture is heated to 212 F. or thereabouts. The rosin melts slowly and dissolves in the impure agent. After standing for about 6 hours at a temperature between about 190 and 200 F., two layers result. The top layer contains the rosin and most of the hydrocarbon sulfonates contained in the impure surface active agent, and the bottom layer contains almost all of the water and salt, organic impurities, coloring matter, and a small percentage of the hydrocarbon sulfonates. The hydrocarbon sulfonates dissolved in the rosin are very highly purified and refined. The bottom layer is drawn off and the top layer is treated with concentrated potash or soda lye to saponify the constituents thereof. The product of this saponification, already containing the purified, substantially salt-free surface active agent and hydrogenated rosin in the desired proportions, is added to the soap in the crutcher or to soap flakes before or during milling in the proper amounts. The product of this saponificatlon may be added to the soap during other stages in the soap making process, if desired.

The following examples will illustrate the present invention and it is to be understood that this invention is not to be limited to the details of these illustrative examples or to the procedure outlined therein since these may be varied rather widely, as desired, as is well-known in the art.

Example 1.100% beef tallow is saponified, settled, dried down to about 12% moisture, flaked in the usual manner in preparing toilet soap and then mixed in an amalgamator in the usual way. A mixture of hydrogenated rosin sodium soap and refined hydrocarbon sulfonates, prepared as above described, is added to the soap flakes in the amalgamator in proportions to provide about 3% by weight of the hydrogenated rosin and about /4 of 1% by weight of hydrocarbon sulfonates with respect to the soap and mixed for a short period of time. The milling operation proceeds in the usual manner and the finished soap cake has a good appearance and lathers freely in cold and medium hard water. The foam is abundant and rich; cleans well; and does not irritate the skin.

Example 2.--To 100% beef tallow liquid kettle soap in the crutcher is added a mixture of hydrogenated rosin and sulfonated hydrocarbons, refined as described above, in the proportions described in Example 1. The soap is now dried and formed into finished soap fiakes in the usual manner. These flakes are very light in color, have a good odor, produce an abundant and rich foam and are suitable for all washing purposes.

Example 3.A soap stock consisting of palm oil and 10% olive oil foots is saponified, settled, dried down to 13% moisture, and fiaked in accordance with the usual practice in making toilet soap. A mixture of hydrogenated rosin soap and purified hydrocarbon sulfonates, refined as described above, is added to the flakes in the amalgamator in an amonut to provide about /4 of 1% by weight of hydrocarbon sulfonates and about 5% by weight of hydrogenated rosin soap with respect to the soap fiakes and milled for a short period of time. The resulting soap does not irritate the skin and compares very favorably in foaming properties with the same type of soap without any additional improving agents, but containing about 7 to 10% of saponified cocoanut oil.

The form in which the soaps or soap preparations in accordance with the present invention are sold in trade depends, of course, on the purpose for which they are intended. Thus, they may be in the form of bars, flakes, sticks, powders, solutions, etc. Regardless of the form of the finished soap, it dissolves readily in water, whether soft or hard, and forms an abundant and rich foam which has excellent cleaning properties. The soap is excellent for shaving.

The soaps of the present invention are high quality. substantially salt-free soaps, of good appearance and with no tendency to crack. They are relatively inexpensive soaps because the amounts of added foam improving materials are so small as to have but a small effect on the ultimate cost. These soaps, in the form of bars especially, wash away very economically. Regardless of the form of the soap, the action thereof on the skin is mild and definitely nonirritating. The addition of the hydrogenated rosin and purified hydrocarbon sulfonates in accordance with the present invention does not require any special equipment and does not introduce any technical difliculties in processing the soap. In fact, no changes in the conventional soap making procedure are required.

If it is desired to impart some special properties to the soap to make it suitable for a particular purpose, this may be done in the usual manner as by adding the desired quantity of one or more antiseptic or germicidal substances, therapeutic substances, perfumes, colors and dyestuffs to the soaps in the desired stage of manufacture.

I claim:

1. A soap composition comprising essentially an alkali metal soap of a tallow soap stock and small amounts of hydrogenated rosin and a purified, substantially salt-free alkali sulfonate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons of 12 to 14 carbon atoms in the molecules, the amount of said sulfonate varying from about to 1 /2% by weight and the said rosin from about 1 to 5% by weight.

2. A soap composition comprising essentially an alkali metal soap of a mixture of a major amount of palm oil and a minor amount of olive oil foots and small amounts of hydrogenated rosin and a purified, substantially salt-free alkali sulfonate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons of 12 to 14 carbon atoms in the molecules, the amount of said sulfonate varying from about A to 1 /z% by weight and the said rosin from about 1 to 5% by weight.

3. A soap composition comprising essentially an alkali metal soap of a tallow soap stock and small amounts of saponified hydrogenated rosin and a purified, substantially salt-tree alkali sulfonate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons of 12 to 14 carbon atoms in the molecules, the amount of said sulfonate varying from about to 1 by weight and the said rosin from about 1 to 5% by weight.

4. A soap composition comprising essentially an alkali metal soap of a soap stock of the class consisting of animal and vegetable fats and oils free from substantial percentages of lauric acid, and small amounts of hydrogenated rosin and a purified, substantially salt-free alkali sulionate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons of 12 to 14 carbon atoms in the molecules, the amount of said sulfonate varying from about to 1 by weight and the said rosin from about 1 to 5% by weight.

5. The soap composition set forth in claim 4 wherein the hydrogenated rosin is saponifled.

6. A soap composition comprising essentially an alkali metal soap of a tallow soap stock and small amounts of hydrogenated rosin and a purified, substantially salt-free alkali sulionate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons having from 12 to 14 carbon atoms in the molecules, the amount of said sulfonate varying from about /2 to 1% by weight and the said rosin from about 1 to 5% by weight.

7. A soap composition comprising essentially an alkali metal soap of a tallow soap stock and small amounts of saponified hydrogenated rosin and a purified, substantially salt-free alkali sulfonate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons having from 12 to 14 carbon atoms in the molecules, the amount of said sulfonate varying from about /2 to 1% by weight and the said rosin from about 1 to 5% by weight.

8. A soap composition comprising essentially an alkali metal soap of a soap stock of the class consisting of animal and vegetable fats and oils free from substantial percentages of lauric acid, and small amounts of saponifled hydrogenated rosin and a purified, substantially salt-free alkali sulfonate of a mixture of hydrocarbons having a predominant portion of straight chain saturated aliphatic hydrocarbons having from 12 to 14 carbon atoms in the molecules, the amount of said sulfonate varying from about V of 1% by weight and the said rosin from about 1 to 5% by weight.

LEOPOLD SAFRIN.