JPS649961B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION The present invention relates to liquid skin cleansers. More particularly, the present invention relates to liquid skin cleansers comprising surfactants and lather enhancers. Cleansing the skin with surface-active cleansers has been a center of great interest. Many people clean and scrub their skin with various surface-active cleansers several times a day. Skin cleansers gently cleanse the skin, cause little or no irritation, do not degrease or dry the skin after frequent regular use. Certain synthetic surfactants are particularly mild. However, a major drawback of mild liquid synthetic surfactant systems when formulated for skin cleansing is poor foaming properties. Compared to the best bar soap standards (bar is rich in coconut soap and overfat), these traditional liquid surfactant formulations have poor foaming properties or poor foaming properties. It has one of the following skin-friendly properties. As expected, foaming properties vary with the choice of surfactant and its concentration. The number of possible liquid surfactant compositions with or without skin sensate agents is numerous. The rheological and phase properties exhibited by prototypes vary widely (ie, dilute liquids, gels, viscous pastes, solutions, emulsions).
The phase stability of the original forms is mostly tolerated for short periods of time, but only a small portion retains their original properties and acceptability over long periods of time. Optimizing foaming as a single variable is a fairly simple method. Known high foaming anionic surfactants in combination with foam enhancers produce acceptable foam volumes. Unfortunately, the highest foaming anionic surfactants generally have the highest sebum removal properties and are also the worst in clinical mildness.
The mildest surfactants with the least ability to remove sebum, such as lauryl ether (12EO) ammonium sulfate (NH ₄ AE ₁₂ S), have extremely poor foaming properties.
These two facts make surfactant selection and foam enhancement optimization methods delicate. It has long been recognized that relatively small amounts of certain solubilizing organic compounds have the ability to increase the foaming power of fatty alkyl sulfates. For example, the use of excess sulfating agent when sulfating lauryl alcohol with chlorosulfonic acid results in a product with very poor foam stability;
It is well known that addition of free lauryl alcohol to this product restores foaming power.
Therefore, lauryl alcohol is the foam promoting builder for lauryl sulfate, and high foaming power commercial lauryl sulfate always contains a small amount of lauryl alcohol from the beginning when it is manufactured. This percentage usually varies from 2% to 10% of the lauryl sulfate present, and the exact content of lauryl alcohol is often the purchasing specification for lauryl sulfate detergents. Lauryl alcohol and others in the fatty alcohol series are certain other cleaning suds builders, although they are reported to be ineffective when used in conjunction with alkyl aromatic sulfonates. In general, the suds-enhancing effect is very specific, and substances that enhance the suds of some detergents may have little or no effect on some others.
Another important property of foam builders is that their effectiveness varies considerably with concentration. An excess amount of foam builder compared to the surfactant present actually has a foam suppressing effect. Fatty monoethanolamides are used commercially as foam builders for fatty alkyl sulfates. In practice, lauryl or coconut monoethanolamide is used because it is more effective than higher grades of the same series. Fatty diethanolamides are preferred as foam builders for alkylaryl sulfonates (GB 693063). Coconut oil fatty diethanolamide is said to be particularly effective and is widely used as a foam builder. This latter product is known to contain, in addition to fatty diethanolamide, some free fatty acids and aminofatty esters [H.T. L. Saunders and E.L. Knatzgus, Soap & Sanitary Chemicals, 29 , No. 6, 45-8
(1953)]. Fatty alkylolamides have also been used in conjunction with soaps to promote and stabilize lather (Zusman et al., Soap and Sanitary Chemicals, 26, No. 4, 37-40, 141 (1950)). US Pat. No. 2,879,231 relates to shampoos that can contain fatty acids and amides. However, the solid bar soap of US Pat. No. 4,151,105, for example, requires 10-30% dextrin, 5-15% starch and 10-30% paraffin, which are undesirable in liquid skin cleansers. Coconut oil fatty acids are
Used to promote plasticity and improved lathering within low PH synthetic bar soaps. Coconut oil fatty acids are used along with lauric acid diethanolamide to supplement coconut fatty acids. In short, the rather stringent requirements in the case of skin cleansers limit the choice of surfactants and the final formulation represents a certain degree of compromise. Gentleness is often obtained at the expense of effective cleaning power, or lathering is at the expense of mildness, product stability, or both. The present invention provides a valuable combination of desirable properties to liquid skin cleansing formulations. One of the objects of the present invention is therefore to provide a liquid skin cleansing composition that exhibits a mild surface action and good foaming properties. Another object of the invention is to provide a low cost liquid skin cleanser. Other objects will become apparent from the detailed description below. SUMMARY OF THE INVENTION (A) Anionic surfactants selected from the group consisting of fatty alkyl sulfates, fatty alkyl ether sulfates, and mixtures thereof, 5
~30% by weight, (B) a foam-enhancing mixture consisting essentially of free fatty acids and fatty alkylolamides having a ratio of 1:3 to 3:1, 0.5 to 12% by weight, (C) from water. the free fatty acid has a chain length of 8 to 18 carbon atoms, and the fatty acid comprises at least 25% of the carbon chain length of less than 14, and the foam-enhancing mixture comprises 10% to 18% of the weight of the surfactant. A liquid surfactant composition is present in an amount of 40% and wherein the composition has a PH of about 4.0 to about 7.0.
Disclosed as an excellent mild synthetic liquid skin cleanser with increased foaming properties. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to liquid skin cleansing compositions containing fatty alkyl sulfate and ethoxylated alkyl sulfate surfactants with optimal foaming properties. For example, coconut oil alkylolamides, which are known to have foam-enhancing properties, are used in conjunction with the surfactants to provide improved foam. However, the present invention further increases the foaming power of the amide by using coconut oil fatty acids as a co-foaming enhancer. The combination of two foam enhancers, coconut oil alkylolamide and coconut oil fatty acid, has a synergistic effect, and at the same total amount of foam enhancer use, the combination produces a volume with a rich creamy consistency. This results in better foaming properties than when each component is used alone in the same amount. More particularly, (A) an anionic surfactant selected from the group consisting of fatty alkyl sulfates, fatty alkyl ether sulfates, and mixtures thereof;
~30% by weight; (B) a foam-enhancing mixture consisting essentially of free fatty acids and fatty alkylolamides having a ratio of 1:3 to 3:1; (C) water, consisting of 0.5 to 12% by weight; the fatty acid has a chain length of 8 to 18 carbon atoms, and the fatty acid consists of at least 25% of the carbon chain length of less than 14, and the foaming enhancing mixture is present in an amount of 10% to 40% of the weight of the surfactant. and wherein the composition has a PH of about 4.0 to about 7.0,
Disclosed as an excellent mild synthetic liquid skin cleanser with increased foaming properties. Surfactants One essential component of liquid skin cleansing compositions is surfactants. The term "surfactant" as used in this invention means a synthetic anionic surfactant. The surfactants of _the present invention are derived from alkali metals (e.g. _sodium or and 1 mole of _C8 - _C22 alcohol (e.g. tallow or coconut oil alcohol) and about 1 to 20 moles, preferably 1 to 13 moles of ethylene oxide (ethoxy groups); The reaction products are alkali metal salts and ammonium salts of sulfuric esters. These are referred to as alkyl sulfate surfactants and alkyl ether sulfate surfactants, respectively. Preferred surfactants for use in the present compositions are, for example, ammonium lauryl sulfate, sodium lauryl sulfate and ammonium lauryl ether sulfate, sodium lauryl ether sulfate or combinations thereof. Preferred single surfactants are alkyl ether sulfates having 1 to 6 ethoxy groups, especially ammonium lauryl ether sulfate and sodium lauryl ether sulfate. A preferred mixture of surfactants is, for example, a mixture of ammonium lauryl sulfate and/or sodium lauryl sulfate with ammonium lauryl ether sulfate and/or sodium lauryl ether sulfate. The amount of surfactant is between 5% and 30%, preferably between 10% and 25%.
%, most preferably 12-22%. Whisk Enhancing Agent The whipping boosting mixture is essentially 1:3 to 3:
1, preferably 1:2 to 2:1, most preferably about 1:1, of free fatty acids and fatty alkylolamide. The foam-enhancing mixture is present in an amount of about 10-40% (most preferably 10-30%) by weight of the amount of mixture present. Optimizing foaming as a single variable is a fairly simple method. High foaming surfactants are used in conjunction with foam enhancers such as fatty acids, fatty alcohols, and fatty alkylolamides to produce maximum foam volume. Unfortunately, high foaming anionic surfactants generally have the best sebum removal properties and are also the worst clinically mild. As mentioned above, these two attributes (mildness and low sebum removal) are important performance characteristics of preferred embodiments of the present invention. The mildest surfactants in terms of sebum-removing properties, such as NH ₄ AE ₁₂ S (lauryl ether (12EO) ammonium sulfate), have very poor lathering properties. These conflicting factors (mildness vs. foaming) make surfactant selection and foaming optimization methods specific. Better lathering compared to traditional liquid soap formulations by selecting appropriate ratios of mild surfactants, high foaming surfactants, and utilizing foam film stabilizing substances. The most preferred embodiment is obtained, which not only has the properties of the compound, but also is relatively mild. The skin cleanser of the present invention is excellent when lathered onto the hands, but under very dirty conditions.
Or if it is made very diluted, as in a shower, the foaming properties are reduced compared to superfat solids containing a large amount (50%) of coconut soap.
However, even under these conditions, the cleaning agents of the present invention are superior to commercially available liquid soaps. This decrease in performance is a simple function of the formulation's reduced cleaning power. However, the overall lathering properties obtained with the compositions of the present invention are superior to most bar soaps and commercially available liquid soaps. Fatty Acid The fatty acid component of the composition is a fatty acid having a chain length of 8 to 18 carbon atoms, with at least 25% (preferably at least 50%) by weight of the fatty acid having 14 carbon atoms.
It has a chain length less than . The fatty acids are preferably double distilled coconut oil fatty acids having an iodine number of about 6 to about 14. Suitable coconut oil fatty acids include, by weight, 15% capric and caprylic acids, 48% lauric acid, 18% myristic acid.
%, palmitic acid 9%, stearic acid 2%, oleic acid 6%, and linoleic acid 2%. Fatty acids used as co-foam enhancers with alkylolamides improve overall foaming properties by increasing foaming. Alkylolamide Higher fatty acid alkylolamide materials exhibit improved foaming creaminess when used together with the surfactants and may particularly improve the stability of the foam generated during skin cleansing. discovered. The acyl groups of the alkylolamides are selected from fatty acids having 8 to 20 carbon atoms, and each alkylol group usually has up to 3 carbon atoms. The amide may be either a dialkylolamide or a monoalkylolamide. Preference is given to using diethanolamides, di- or monoisopropanolamides and monoethanolamides of fatty acids having about 10 to 14 carbon atoms in the alkyl group. Examples are lauric acid, capric acid,
Monoethanolamides and diethanolamides of myristic acid and coconut oil fatty acids, and mixtures thereof. Alkylolamides substituted by addition of ethylene oxide groups can also be used, preferred examples being the monoethanolamides mentioned above condensed with 1 or 2 moles of ethylene oxide,
diethanolamide, and isopropanolamide. The solids content of liquid products can vary and is usually about 7-40% by weight of the composition, with the balance being primarily water. Predetermined proportions of the ingredients are combined in an aqueous solubilization medium to prepare a substantially uniform product of desired physical properties. Aqueous Carrier The skin cleanser is preferably in the form of a liquid or cream in which water is the primary diluent. The amount of water within the composition typically ranges from about 60% to about 93% by weight, preferably
It is 70-85%. Purified (distilled) water is preferred. PH Adjustment Agent The PH of the liquid skin cleansing composition should be within the range of about 4.0 to about 7.0, preferably within the range of about 5.0 to about 6.0. Keep fatty acids in an unsaponifiable state by keeping the pH in the acidic range. Suitable PH regulators are, for example, HCl, citric acid, phosphoric acid, succinic acid and sodium citrate/citric acid mixtures. Optional Ingredients The skin cleansing agent may contain various non-essential ingredients suitable for improving this type of composition in various ways. Typical optional ingredients are well known to those skilled in the art and include, for example: Preservatives such as benzyl alcohol, methylparaben, propylparaben, 3-isothiazolinone (kathon CG sold by Rohm & Haas) and imidazolidinyl urea can be used in amounts of 1 to 5000 ppm; thickeners. and viscosity modifiers, such as polyethylene glycol, sodium chloride, ammonium chloride, sodium sulfate, carboxymethylcellulose, methylcellulose, polyvinyl alcohol, and ethyl alcohol; suspending agents, such as magnesium/aluminium silicate; fragrances; dyes; opacifiers , such as behenic acid, ethylene glycol distearate and calcium stearate; sequestering agents such as disodium ethylenediaminetetraacetate; emollients, humectants and various other skin treatment ingredients such as glycerin;
Buffers and builders, such as citrate and phosphate; foam modifiers, such as polymers, namely polyacrylamide and derivatives of cationic polymers, such as JR400 ^™ sold by Union Carbide. When present, each such agent generally represents about 0.01% to about 5% by weight of the composition. Additional surfactants can also be added to the composition as optional ingredients. Although the optional surfactant may be selected from other types of surfactants, the preferred types are nonionic surfactants and amphoteric surfactants. Trace amounts of fatty alcohols can optionally be used as an ingredient. Alcohol can perform a number of functions, for example improving foam properties such as volume and creaminess. Surfactants made from fatty alcohols often contain some free fatty alcohol. Method of Preparation The liquid skin cleansing compositions of the present invention are prepared by the mixing techniques disclosed herein. The preparation of the compositions of the invention is illustrated in the following examples. Uses of the Compositions In its method aspects, the present invention cleans the skin by contacting the skin with an amount of a cleansing agent composition effective to cleanse the skin, and rinsing the cleansing agent from the skin. It consists of a method to The effective amount of each will depend on variable factors such as the amount of soil on the skin, the type of soil on the skin, the amount of surfactant in the cleansing composition, and the like. Generally, the effective amount will be about 0.5 to about 5 grams per use. The following examples are illustrative of the invention and are not intended to limit it. Example Ingredients Weight% Purified water 71.3 Alkyl☆ Ammonium sulfate 20.0 Coconut fatty acid 2.0 Coconut monoethanolamide 2.0 Glycerin 3.0 JR400☆☆ 0.5 Ethylene glycol distearate 1.0 Flavor 0.2 Total 100.0 ☆: Average linear chain with 12 to 14 carbon atoms Derived from fatty alcohols ☆☆: Cationic cellulose polymers marketed by Union Carbide The example liquid skin cleansing compositions are preferred for their overall high lather volume performance. Example Ingredients Weight% Purified water 72.3 Alkyl☆ Ether ammonium sulfate (ethoxylated with 1 mole of ethylene oxide) 20.0 Coconut fatty acid 1.5 Coconut monoethanolamide 1.5 Glycerin 3.0 JR400 1.5 Ethylene glycol distearate 1.0 Flavor 0.2 Total 100.0 ☆: Number of carbons 12 Derived from fatty alcohols with an average linear chain of ~14 This example is most preferred for optimal foaming/surfactant mildness balance. Example ingredient weight% Purified water 70.3 Alkyl☆ Ammonium sulfate 6.7 Alkyl☆ Ammonium ether sulfate (ethoxylated with 12 moles of ethylene oxide) 11.0 Alkyl glyceryl ether sulfonate 2.3 Coconut fatty acid 2.5 Coconut monoethanolamide 2.5 Glycerin 3.0 JR400 0.5 Ethylene glycol distearate 1.0 Flavor 0.2 total 100.0 ☆: The example derived from a fatty alcohol having an average straight chain of 12 to 14 carbon atoms is a preferred composition due to its mildness. EXAMPLE A method that can be used to prepare an example composition of the invention is as follows. 1. Mix surfactant (one or more) and purified water together at room temperature. 2 Then add glycerin. 3 Add coconut fatty acid and coconut monoethanolamide to the mixture simultaneously under stirring. 4 Add ethylene glycol distearate. 5 Next, make batches of about 150〓~160〓(65~70〓)
°C) and become completely fluid. 6. Add JR400 (cationic cellulose polymer) slowly and carefully to disperse the polymer solids as uniformly as possible. 7 A mixing time of 20 minutes is required to dissolve all ingredients and obtain a clear solution. 8 Adjust the PH of the formulation to 5.0 using hydrochloric acid. 9. Cool the product to room temperature and add flavoring. A foam enhancer is preferably added at the same time. This is done either at room temperature or by adding a pre-eutectic foaming enhancer to the pre-heated surfactant mixture. Method 1 for evaluating foam volume on used hands: Wash hands thoroughly to remove natural surface oils or other dirt. This normalizes hands to the same initial baseline condition before each series of evaluations. 2 Dry your hands. 3 Next, wet your hands with warm water [97〓 (approximately 36.1℃), 7 grains]. 4 Place 1ml of the liquid product in the palm of one hand. 5. Rub your hands together 10 times (10-15 seconds) to create bubbles. 6. Gently rinse the foam on your hands with 100ml of cold distilled water and place in a wide-mouth graduated cylinder. 1 after rinsing is complete and before measuring lathering.
Wait for a minute to allow excess water to drain from the foam. Read the foam height with a graduated cylinder and record the volume of foam above the water surface. 7. Rinse hands thoroughly and repeat steps 2-6 for each serial evaluation. Evaluation of the weight of foam on the hand This method is very similar to the evaluation of foam volume, with the following variations: 1. Replace the standard graduated cylinder with a graduated cylinder with a stopper. 2. Before step 6, weigh the tare weight of the cylinder. 3. After recording the volume of foam in step 6, drain the water at the bottom of the cylinder through a cot plug. 4 Then weigh the cylinder. Subtracting the tare weight of the cylinder from this weight gives the foam weight. In the examples below, NH ₄ AS, NH ₄ AE ₁ S,
NH ₄ AE ₁₂ S, AGS, CnFA and CnMEA represent alkyl ammonium sulfate, alkyl ether ammonium sulfate (1 and 12 ethoxy groups, respectively), sodium alkyl glyceryl ether sulfonate, coconut monoethanolamide and coconut fatty acid, respectively. The alkyl groups of all components were derived from fatty alcohols with an average chain length of 12 to 14 carbon atoms.

[Table] Examples of foam volumes above the front cover 180 ml Example 220 ml Example 230 ml Example 270 ml Example 240 ml Example 250 ml The total amount of surfactant and foam enhancer used in each of Examples ~ was 25% by weight. Note the synergistic lather co-enhancement benefits of the compositions (Examples) with respect to creamy lather volume, which is indicative of the preferred liquid skin cleansing compositions of the present invention. The base formulations of Examples A-F were ₁₃ % _NH4AE1S ,
Glycerin 2%, sodium citrate 0.375%,
Citric acid 0.225% and ethylenediaminetetraacetic acid
It is 0.2%. Examples C-E illustrating the invention show improved foaming properties over Examples A, B and F in terms of volume with a creamy consistency.

Table: Formulation A without foam enhancer has a low foam volume of 158. Formulation B with only acid foam enhancer has a high foam volume of 218 but has the poorest foam in terms of cream quality as shown by a density of only 6.6. Formulation F with only the amide foam enhancer has a creamy foam density of 8.0 but exhibits the poorest foam volume of 148. It can be seen that formulations C, D and E of the invention provide improved skin cleansing with respect to creamy foam volume. Formulations C, D and E exhibit foam volumes of 225, 198 and 192, respectively, all of which are higher than the volume of Formulation F, which contains only the amide foam enhancer, at 148. Also, formulations C, D, and E exhibited creamy foam densities of 7.4, 8.6, and 7.7, respectively, all of which had a foam density of 6.6 for formulation B, which contained only the acid foam enhancer.
It's more creamy.

Claims (1)

Claims: 1. (A) about 5 to 30% by weight of an anionic surfactant selected from the group consisting of fatty alkyl sulfates, fatty alkyl ether sulfates, and mixtures thereof; (B) essentially about about 0.5-12% by weight of a foam-enhancing mixture of free fatty acids and fatty alkylolamides having a ratio of 1:3 to about 3:1;
and (C) water, wherein the free fatty acids have a chain length of 8 to 18 carbon atoms, and the fatty acids consist of at least about 25% of the chain length of less than 14 carbons, and the foam-enhancing mixture is surfactant. Approximately 10% to approximately 40% of the weight of the agent
% and the composition is from about 4.0 to about 7.0
A liquid skin cleansing composition characterized by having a PH. 2 said whisking-enhancing mixture is about 2:1 to about 1:
2 and is present in an amount of about 15 to about 30% by weight of the total surfactants present. 3. A liquid skin cleansing composition according to claim 2, wherein the free fatty acid comprises at least 50% by weight of a fatty acid having a chain length of less than 14 carbon atoms. 4. The liquid skin cleansing composition according to claim 3, wherein the alkylolamide is coconut monoethanolamide. 5. The liquid skin cleansing composition of claim 4, wherein the surfactant is selected from the group consisting of ammonium lauryl sulfate, sodium lauryl sulfate, ammonium lauryl ether sulfate, sodium lauryl ether sulfate, and mixtures thereof. 6 Claim 5 in which the PH is about 5.0 to about 6.0
The liquid skin cleansing composition described in Section 1. 7 The foam-enhancing mixture is about 10% of the weight of the surfactant.
7. The liquid skin cleansing composition of claim 6, wherein the composition is present in an amount of from % to about 30%. 8. The liquid skin cleansing composition according to claim 7, wherein the surfactant is ammonium lauryl sulfate. 9. The liquid skin cleansing composition according to claim 7, wherein the surfactant is ammonium lauryl ether sulfate having 1 to 6 ethoxy groups. 10 Claims 1, 2, 3, 4, 5, and 5, wherein the surfactant is a mixture of ammonium lauryl sulfate and ammonium lauryl ether sulfate having 1 to 13 ethoxy groups. The liquid skin cleansing composition according to item 6 or 7. 11. Claims 1, 2, 3, and 4 wherein the surfactant is present in an amount of about 10% to about 25%.
Section 5, Section 6, Section 7, Section 8 or Section 9
The liquid skin cleansing composition described in Section 1. 12 Claims 1, 2, 3, and 4 wherein the surfactant is present in an amount of about 12% to about 22%
Section 5, Section 6, Section 7, Section 8 or Section 9
The liquid skin cleansing composition described in Section 1.