US3224976A - Detergent bar - Google Patents

Description

United States Patent 3,224,976 DETERGENT BAR Richard Edward Farrar, Morris Plains, and Albert Lyle Sehulerud, Nutley, N..'l., assignors to tIolgate-Palmolive Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Aug. 8, 1960, Ser. No. 47,925 2 Claims. (Cl. 252-119) This invention relates to soap-synthetic organic detergent bars which are suitable for cleaning human skin. They are especially useful as detergents for persons whose skins are deficient in lipophilic materials.

During cleaning of the skin in the conventional manner with a cake or bar of soap, the Washing and emulsifying actions of the soap, together with the mechanical scrubbing of the skin, remove skin oils, as well as the dirt, foreign matter, perspiration residues and flakes of dead skin which it is desired to wash off. Under most normal conditions removed skin oils are quickly replaced so that the person using the soap bar usually does not experience any discomfort due to excessive drying of the skin. However, many people suffer from dry skins, usually either because the body mechanism for replacing skin oils does not operate efiiciently or because of subjection of the skin to excessive washing. Therefore, it has often been found desirable to use lotions or oils for increasing the suppleness of the skin by application of these materials after the bath or after washing the hands.

The removal of oils from the skin can be somewhat decreased by the inclusion in a soap or other detergent composition of emollient agents, which appear to function either by decreasing the ability of the detergent to dissolve and emulsify out the skin oils or else by aiding in the redeposition of lipophilic material on the skin surface.

The inclusion of oleaginous materials or superfatting agents usually causes soap bars to become softer and very often adversely affects the lathering ability and also the character of the detergent compositions lather. Such disadvantageous properties of the product may be tolerated by those who are very seriously bothered by a dry skin condition and therefore are willing to accept the useful emollient detergent, despite its inherent faults. Still, for a bar to achieve widespread acceptance by the public it should possess the usual properties of a good toilet soap.

Usually, the addition of superfatting materials softens a soap, making it more diflicult to plod and press with standard soap making equipment. It also generally reduces the capability of the soap holding the usual percentages of moisture because the superfatting material has an excessive plasticizing action which, supplemented by the action of Water, makes the product excessively soft. Bars that can be made satisfactorily often possess properties which make them unacceptable during use. Thus, the softer of these bars tend to smear on the wash stand, are consumed too quickly, due to the presence of the soft surface layer and oftentimes lather poorly and slowly. Some of the emollient agents that have been added to soaps tend to migrate through cake of soap in storage to form a hard surface film which cuts down on the initial lathering power of the bar of soap when the consumer is first using it.

The above disadvantages are those which have been found attendant to the addition of emollients to soap compositions. It should be remembered that the ordinary soaps made from mixtures of major proportions of tallow and minor proportions of coconut oil or equivalents are fairly hard and can tolerate the addition of small quantities of oleaginous materials without softening as much as is usually the case with synthetic detergents. The synthetic organic detergents are generally softer than soap detergents and therefore the problem of excessive softening or plasticizing of the compositions is magnified. Thus, it was considered usual to find, as the inventors did, that the inclusion of a certain mixture of emollient materials in soap-synthetic detergent bar compositions would allow the production of these bars on standard soap making equipment and still would make a product that would be highly acceptable to the discriminating consumer. Such a bar is not unduly tacky despite the presence of the emollient in addition to the generally softer, more soluble combination of synthetic organic detergent with soap. The lather generated by such a bar during use is especially creamy and was found by many users to be superior to that obtained from a soap-synthetic bar containing no such emollient combination.

The emollient material composition employed in the present soap-synthetic detergent bars is one comprising about 4 to 11% of petrolatum, 30 to of the petrolatum weight of glycerol, and about 1 to 2.5% of lanolin, all the foregoing percentages being on a final bar basis. The combination of petrolatum and lanolin with the glycerol in the proportions cited yields an emollient composition which gives a skin softening effect discernible by the users of the detergent product but does not excessively plasticize the bar nor seriously affect its processing characteristics detrimentally. The rather large quantity of emollient material has an appreciable and desirable effect on the lather characteristics of the product, as well as on the skin of the user and does not make the bar unacceptably soft.

In addition to the special emollient material, the novel soap-synthetic detergent bar of this invention is one comprising 40 to 77.8% soluble alkali metal soap of higher fatty acids with a major proportion thereof being sodium soap, 8 to 30% alkali metal salt of a synthetic organic detergent which is a sulfuric reaction product, and 8 to 14% moisture. In a preferred formula there are present 4 to 7% petrolatum, l to 2.5% lanolin, 1.2 to 4.9% glycerol (30 to 70% of the petrolatum), 40 to 60% soluble sodium soap of fatty acids of 10 to 18 carbon atoms, 8 to 30% sodium salt of substantially saturated higher fatty monoglyceride sulfate in which the higher fatty acids group is of 10 to 18 carbon atoms, 2 to 10% starch and about 10 to 13% moisture. In place of the 8 to 30% monoglyceride sulfate an especially useful product contains 8 to 20% of that material with 3 to 10% of a curd dispersing detergent added.

The petrolatum employed in the invented combination soap-synthetic detergent bars is preferably that which is commonly known as white petrolatum. This is a mixture of petroleum hydrocarbons covering a range of about 16 to 32 carbon atoms per molecule, usually averaging about 22 carbon atoms. These higher molecular weight petroleum fractions are practically odorless and colorless and do not detrimentally affect either the aroma or appearance of toilet soaps and detergents, which is so important to their acceptance by the consumer. Less than about 4% of petrolatum in the invented bar products is usually considered insuflicient to give a significant, readily discernible effect to those persons bothered by dry skin conditions, While more than about 11% will often change the bar characteristics to make it more difficut to produce and also to soften it excessively so that it is not as acceptable a consumer product.

With the petrolatum, as another of the emollient constituents of these products there is present 1 to 2.5% lanolin, preferably about 1.5% thereof. Lanolin more closely approximates the chemical nature of the sebum than does petrolatum and it supplements the petrolatum and improves the condi-tioning of the skin. Although lanolin usually has a very detrimental effect on the latheri-ng power of soap, even more so than petrolatum, in the invented compositions this effect is appreciably lessened and the lathering quality is even improved, apparently due in part at least to the presence of glycerine in these bars. The lanolins employed may be in the form of the various derivatives now known and used including the lanolin esters and ethoxylates but natural lanolin is preferred.

The glycerine employed is used in quantity dependent on the amount of other emollients present, particularly dependent on the major emollient, petrolatum. Usually about 50% of the amount of petrolatum is the proportion of glycerol desired but this range may be from 30 to 70%. Although both petrolatum and lanolin have a softening effect on the combination bar, as do the normal amounts of moisture present in such bars, with the present emollient composition it has been found possible to include rather high amounts of moisture in the bars despite the pressence of liquid and unctuous substances in the formula. This is especially the case when the percentage of petrolatum is from 4 to 7%. Above 7% etrolatum, it is usually desirable to use a moisture content in the lower half of the 8 to 14% range, but 8 to 11% moisture is still a reasonable commercial level.

The compatibility of these emollient detergent bar compositions with proportions of moisture usually used in soap bars is an important advantage of these products because it decreases the necessity for drying soap chips to very low moisture contents. In addition to attendant saving in drying costs, and faster production and more eflicient utilization of equipment, lower drying temperatures may be employed, helping to maintain the stability of the sulfuric reaction product detergent. At 8 to 14% bar moisture content it has been found that soap-synthetic detergent compositions can still be plodded and pressed on standard factory equipment even though the rather large percentages of petrolatum and lanolin are also present, which would be expected to make the formula softer, tacky and more difiicult to manufacture efficiently. In addition to the beneficial effect of the glycerol in allowing better production and in improving the properties of the bar in storage and use, it also is thought that it aids the petrolatum to penetrate the upper skin cell layers and thereby helps it to be retained on the skin, where it can exert its softening and lubricating effect.

The water solubel alkali metal soap which is usually the major constituent of these soap-synthetic detergent bars is usually over 75% sodium soap and very often is entirely sodium soap. While it is preferred to employ soaps derived from approximately equal parts of coconut oil and tallow, those containing other proportions of these oils or their equivalents are also useful. If the content of saturated fatty acids in the 12 to 14 carbon atom range (and even the small proportion below 12 carbon atoms, also usually found in coconut oil) is substantial relative to the content of 16 and 18 carbon acids present, the bar made will lather more quickly and it has been found to be harder and less apt to slough in a soap dish or in water than a bar containing greater quantities of unsaturated soaps or those of 16 to 18 carbon atoms. Thus, it is preferred to utilize a fat charge in the soap making process which will result in a soap predominantly of higher fatty acids of to 18 carbon atoms, preferably 85% or more of 12-18 carbon atoms, and having 25 to 60% thereof of 10 to 14 carbon atoms and 75 to 40% of 16 to 18 carbon atoms, the soap being more than 65% of saturated fatty acids.

The alkali metal salt of sulfuric reaction product detergent, usually the sodium salt is one having a fatty, alkyl or aliphatic portion of 10 to 18 carbon atoms, preferably in a straight line configuration. The most desirable of these compounds are the monoglyceride sulfates, usually esters of coconut oil fatty acids. Other preferred sulfuric reaction products, included in which term are sulfates and sulfonates, are the curd-dispersing detergents, such as higher acyl amides of amino lower aliphatic sulfonic acid in which the acyl group is of 12 to 18 carbon atoms,

the alkyl linking nitrogen and sulfur is 2 to 3 and the nitrogen may be alkylated with a 1 to 3 carbon group. Among other sulfuric reaction products which may be useful in various amounts in these compositions are the fatty alcohol sulfates, the higher alkyl benzene sulfonates, in which the alkyl group is normal, the higher alkyl ether glyceryl sulfonates and the methyl or other lower alkyl, esters of alpha sulfonated higher fatty acids. Of these materials, those found by experience to be of primary importance and utility are the monoglyceride sulfates and the higher acyl amides of taurine, such as the sodium .oleic acid amide of N-methyl taurine, which taurides are excellent curd dispersing compounds.

As had been mentioned previously the problem of preventing exessive softness of superfatted detergent bars is a greater one than that with superfatted soaps because the more soluble detergents tend to soften combination soapsynthetic detergent bars and also tend to make them more liable to absorb moisture, slough and smear during use, all of which characteristics are undesirable. It has been discovered in the past that the presence of starch in formulas of this type has the effect of limiting these undesirable synthetic detergent characteristics in the combination bar. Thus, bars comprising monoglycenide sulfate, higher fatty acid amides of N-alkyl-ated taurine, soap and moisture are improved by the presence of small proportions of starch. It has been found by the present inventors that starch, with the emollient composition disclosed, also allows them to produce an emollient combination soap-synthetic detergent bar which can satisfactorily compete with soaps on the basis of physical characteristics of moisture absorption, drying rate, slough and softness, all of which one might expect to be poor in a soap-synthetic detergent bar and would certainly expect to be poorer in a bar containing rather substantial proportions of emollient material. It is preferred that the starch used should be that desigated as alkali stable. This means that the starch does not hydrolyze, discolor or change chemically to an objectionable extent in the presence of the soap, synthetic detergents and moisture in this combination bar. The test of S-choc-h and Jensen as described at pages 679 and 680 of the text Chemistry and Industry of Starch, 2nd Edition (1950), by Ralph W. Kerr, should result in a maximum alkali number of about 10 and preferably 5 or less. Instead of using natural starch obtained from corn or potatoes and usually containing up to 30% amylose, one may use a starch fraction such as amylopectin or those starches containing 98% amlyopectin. In view of the similar structure of amylopectin and other starches these compounds as well as modified starches are included within the word starch as employed in this specification and in the claims.

The amount of moisture used in making these combination bars should be sufiicient to allow for efficient plodding and pressing at high speeds without excessive tackiness or Without the opposite effect, a shortness of the bar product. It is preferred to use from 10 to 13% moisture with these compositions but, depending upon the particular detergents, soaps and quantities of emollient and glycerol present, one may use from 8 to 14% and still obtain satisfactory products. As has been mentioned, when employing 8 to 11% petrolatum moisture content is preferably reduced to about 8 to 11%.

Due in part at least to the presence of moisture in these bars, it has sometimes been found that the starch used will discolor, even though it may be what is designated as an alkali stable starch. Such discoloration can be prevented by the addition of a small proportion of hisulfite compound such as sodium metabisulfite which apparently has a reducing effect and presents color development even in the presence of the petrolatum and lanolin emollients. Other adjuvants may also be included in these compositions. Among these are the bactericides, e.g., hexachlorophene, trichlorocarbanilide, halosalicyl-haloanilides, mercurials; perfumes; pigments and opacifying agents, e.g., titanium dioxide; dyes and colorants; brighteners, e.g., aminostilbenes; sequestrants, e.g., tetrasodium ethylene diamine tetraacetate; antioxidants and stabilizers, e.g., stannic chloride, stannous chloride, ditertiary-butyl para cresol; and so forth. The amount of adjuvants should be that sufiicient to impart the desired activity to the product without substantially adversely affecting the bar properties, such as detergency, emmoliency, production and use characteristics. Usually the total amount of such adjuvants will be less than and preferably less than 5%.

To prevent the combination detergent bar from exhibiting crystallization on the surface thereof, the proportion of water soluble alkali metal sulfates and chlorides should be held to a practical minimum. Since more than 7% of these salts, in combination, causes undesirable crystallization, the content thereof should be kept lower than that limit, preferably less than 5%. Usually there will be present at least about 1% of these salts as unremoved products of neutralization of the detergent materials.

The bars of this invention may be made by the usual methods employed for manufacturing corresponding soap products, with only the minor modifications thereof which would be known to those skilled in the art of making combination soap-synthetic detergent bars. The various constituents of the formulas are preferably mixed in the crutcher except for the emollients which are added subsequently. The crutcher mix is dried to the proper moisture content and the soap-synthetic detergent chips are broken up and blended with emollient and other desired adjuvants in the amalgama-tor. Usually the starch is not hydrated appreciably in either the crutcher or in the drying operation, lower alcohol being added to the crutcher to prevent such hydration. Of course, in the amalgamation step the moisture content may be further adjusted by addition of water. The amalgamator mix is then milled in conventional manner to form a homogeneous chip which is next compacted and extruded, usually by a soap plodder. After plodding, the extruded bar is cut to lengths and pressed in a conventional soap press, such as the standard high-speed duplex press in which opposed dies from the soap cake in a rotatable die box.

The following examples are given to illustrate the invention but it is evident that they should not be regarded as limitative thereof. All amounts and percentages in the specification and claims will be by weight unless otherwise indicated.

Example I Percent Sodium hydrogenated coconut oil fatty acids mono- The synthetic organic detergents, soap and starch are mixed in a crutcher (together with accompanying salts and ether solubles) to form an aqueous solutiondispersion or slurry. Isopropanol is present in sulficient quantity to prevent gelation of the starch, which gelation in the crutcher interferes with satisfactory mixing and pumping and often results in a spotty burnt-like discoloration on the dried chip and soap bars subsequently made from such crutcher mixes. Into the crutcher one also adds the sodium metabisulfite and soap stabilizer, an antioxidant.

After mixing to substantial homogeneity, preferably at elevated temperature, the slurry is pumped to a film drier and the chips or ribbons resulting are broken up and blended with the other component materials in an amalgamator. After addition of chips to the amalgamator the pigment and color solution are added. Meanwhile, a uniform melt of petrolatum, lanolin and glycerol is made by heating to about 110 F. and the emollient composition is admixed with the soap-synthetic detergent chips. Following sufiicient mixing to evenly distribute the emollient, perfume is added and the amalgamator mix is milled to homogeneity, plodded, cut and pressed in the usual manner for making soap and soap-synthetic detergent bars.

The bars made were evaluated for emollient effect, as well as for lathering speed and quality, hand washing performance, curd dispersion, sloughing, abrasion resistance, appearance and tactile qualities. They were satisfactory in all these respects and, despite the comparatively great content of emollient and no special hardening agents used, were not unduly soft. The comparative hardness of the bar is reflected in low sloughing and abrasion rates as Well as in its capability of being processed like soaps and other soap-synthetic detergent bars containing no emollient.

Additionally, the bars yielded a rich creamy lather, firmer and more stable than that usually obtainable from synthetic detergent bars and combination soap-synthetic detergent products. With respect to bars devoid of the emollients, lather is often quick-forming but less stable, sometimes even being characterized as lacy to indicate its loose, open, large bubble structure. Although the lather created in washing with the present product is like or better than that obtainable from a very good soap free of synthetic detergent, it is generated at a rate much greater than that found for such soap and forms far less undispersed curd in hard water. A further advantage of the present bars is in the minimizing of the greasy feeling associated with addition of superfatting materials to soap bars. The synthetic detergent and alkali stable starch decrease this effect, giving the bars a more pleasant soaplike feel.

Example II Percent Water soluble sodium soap (made from a fat charge of parts tallow and 20 parts coconut An emollient combination soap-synthetic organic detergent bar of the above formula was made by mixing together in an aqueous slurry, aqueous solutions or dispersions of the soap, sodium sulfonate of methyl ester of fatty acids and soap stabilizers. Isopropyl alcohol was added to the crutcher to improve the miscibility and aid in the drying of this composition. The crutcher mix was dried in a film drier to a moisture suitable for producing a combination soap-synthetic detergent bar within the 8 to 14% range. During the drying essentially all of the lower alcohol was evaporated. The dried chips were blended with opacifier and a melt of mixed emollient composition compounds, after which perfume was added and the mixture was amalgamated, milled, plodded and pressed to cake form.

During the procesing, observations were made to determine whether any difficulty would be encountered in the various steps of the making operations. It was concluded that the product processed much like soap, being milled, plodded and pressed without the difiiculties which might have been expected in emollient combination soapsynthetic detergent compositions.

Evaluations of the finished bar establish that it lathers and cleans very well, feels like soap, is sufiiciently hard to be acceptable to the consumer, is not excessively soluble in the soap dish (being as good in resistance to sloughing as commercial toilet soaps) and forms only small, unobjectionable amounts of undispersed curd in hard water. It is apparent from washing tests that this bar forms appreciably less objectionable curd or bathtub ring than does a soap bar containing the same proportions of added emollients.

In other experiments in which combination soap-synthetic detergent bars containing soap and sodium sulfonates of methyl esters of fatty acids were made it had been found that an increase in the coconut oil fatty acids content of the soap stock produced a somewhat harder bar and diminished any slight tendency of the product to exhibit a tackiness. The bars described in this example were not objectionably tacky but should a formula be made which does not have the desirable surface smoothness and feel associated with emollient soaps, this can be corrected by increasing the coconut oil soap content.

Example III Percent Sodium higher fatty acids monoglyceride sulfate (fatty acids being mixed C12, C18) 12.6 Sodium higher fatty acid amide of N-methyltaurine (derived from tallow) 4.2 Alkali stable starch (Stein-Hall, 91% active) 4.2 Sodium soap derived from equal parts coconut oil and tallow 46.9 White petrolatum 10.0 Lanolin, anhydrous 1.5 Glycerine .0 Sodium chloride 1.4 Sodium sulfate 0.7 Moisture 8.5 Other ingredients (pigment, dye, perfume, stabilizer, unreacted and by-product ether soluble fats) 5.0

This composition was made according to the same general procedure described in Example I. The finished product was evaluated for performance and was found to be an excellent mild soap-synthetic detergent bar which left the skin feeling softer than comparable products containing no added emollient. The lather formed was creamy and the foaming rate was acceptable. The bar was sutficiently hard and processed well despite its very large content of emollient ingredients. The presence of the emollient 'had a perceptible effect on both the appearance of the dry bar and the feel of the bar during washing. It will be noted that the proportion of water '8 employed is 'in the lower part of the 8 to 14% range to compensate in part for the presence of more emollient. However, it appears that even higher moistures than this will also make satisfactory bars.

The above invention has been described in conjunction with illustrative examples thereof. It will be obvious to those skilled in the art who read this specification that other variations and modifications of the invention can be made and various equivalents substituted therein without departing from the principles disclosed or going outside the scope of the specification or purview of the claims.

What is claimed is:

1. A milled and plodded detergent bar particularly suitable for cleaning dry skin comprising 40 to 60% of water soluble sodium soap of higher fatty acids of 10 to 18 carbon atoms, 25 to 60% thereof being of 10 to 14 carbon atoms, to 40% being of 16 to 18 carbon atoms and the soap being 65 to of soap of saturated higher fatty acids, 8 to 20% of sodium higher fatty acid monoglyceride sulfate having a fatty acyl group of 10 to 18 carbon atoms, 3 to 10% of sodium salt of higher fatty acyl amide of a lower amino sulfonic acid in which the fatty acyl group is of 12 to 18 carbon atoms and the lower amino sulfonic acid is of 2 to 3 carbon atoms between the amino and sulfonic acid groups, 4 to 7% of petrolatum, 30-70% of glycerol by weight of the petrolatum, 1 to 2.5% of lanolin, 2 to 10% of starch having a maximum alkali number of about 10 and 8 to 14% of moisture.

2. A milled and plodded detergent bar particularly suitable for cleaning dry skin comprising 40 to 60% of water soluble sodium soap of higher fatty acids of 10 to 18 carbon atoms derived from a mixture of equal parts tallow and coconut oil, 8 to 20% of sodium coconut oil fatty acids monoglyceride sulfate, 3 to 10% of sodium salt of the higher fatty acyl amide of N-methyl taurine in which the acyl group is of 16 to 18 carbon atoms, 4 to 7% of white petrolatum, 30-70% of glycerol by weight of the petrolatum, 1 to 2.5% of lanolin, 2 to 10% of starch having a maximum alkali number of about 10, 10 to 13% of moisture and less than 5% total of water soluble alkali metal sulfates and chlorides.

References Cited by the Examiner UNITED STATES PATENTS 1,906,484 5/1933 Nuesslein 252152 2,438,169 3/1948 Hoyt 252-121 2,494,580 1/1950 Preston 252121 2,714,093 7/1955 Blumenthal 252-421 XR 2,749,315 6/1956 Faier 252117 2,781,320 2/1957 Jelinek et al 252-121 2,894,912 7/1959 Geitz 252--121 2,921,907 1/1960 Kleyn 252107 FOREIGN PATENTS 796,627 6/ 1958 Great Britain. 799,075 7/ 1958 Great Britain.

OTHER REFERENCES Thomssen: Modern Cosmetics, published by Drug and Cosmetic Industry, 3rd. ed., 1947, pp. 119, 120, 123, 124.

JULIUS GREENWALD, Primary Examiner.

Claims (1)

1. A MILLED AND PLODDED DETERGENT BAR PARTICULARLY SUITABLE FOR CLEANING DRY SKIN COMPRISING 40 TO 60% OF WATER SOLUBLE SODIUM SOAP OF HIGHER FATTY ACIDS OF 10 TO 18 CARBON ATOMS, 25 TO 60% THEREOF BEING OF 10 TO 14 CARBON ATOMS, 75 TO 40% BEING OF 16 TO 18 CARBON ATOMS AND THE SOAP BEING 65 TO 100% OF SOAP OF SATURATED HIGHER FATTY ACIDS, 8 TO 20% OF SODIUM HIGHER FATTY ACID MONOGLYCERIDE SULFATE HAVING A FATTY ACYL GROUP OF 10 TO 18 CARBON ATOMS, 3 TO 10% OF SODIUM SALT OF HIGHER FATTY ACYL AMIDE OF A LOWER AMINO FULFONIC ACID IN WHICH THE FATTY ACYL GROUP IS OF 12 TO 18 CARBON ATOMS AND THE LOWER AMINO SULFONIC ACID IS OF 2 TO 3 CARBON ATOMS BETWEEN THE AMINO AND SULFONIC ACID GROUPS, 4 TO 7% OF PETROLATUM, 30-70% OF GLYCEROL BY WEIGHT OF THE PETROLATUM, 1 TO 2.5% OF LANOLIN, 2 TO 10% OF STARCH HAVING A MAXIMUM ALKALI NUMBER OF ABOUT 10 AND 8 TO 14% OF MOISTURE.