WO1995013355A1

WO1995013355A1 - Cleansing compositions

Info

Publication number: WO1995013355A1
Application number: PCT/US1994/012495
Authority: WO
Inventors: Luis Carlos Dias; Ronald Scott Baur; Robert Raymond Schmidt
Original assignee: The Procter & Gamble Company
Priority date: 1993-11-11
Filing date: 1994-10-31
Publication date: 1995-05-18
Also published as: GB9323306D0; CA2176008A1; JPH09505098A

Abstract

A liquid personal cleansing composition comprising: (a) from about 6 % to about 20 % by weight of a mixture of alkali metal or ammonium hydroxide neutralized fatty acid and organic base neutralized fatty acid in a weight ratio of from about 10:1 to about 1:1; (b) from about 0.1 % to about 5 % by weight of unneutralized fatty acid; (c) from about 0.5 % to about 20 % by weight of a synthetic surfactant selected from anionic, nonionic, cationic, zwitterionic and amphoteric surfactants, and mixtures thereof; and (d) water; and wherein the weight ratio of neutralized fatty acid to unneutralized fatty acid is greater than about 2:1, and wherein the total fatty acid mixture has a C12 content of less than about 5 % by weight. The compositions exhibit improved lather, product stability, mildness, skin feel and rinse-off characteristics.

Description

CLEANSING COMPOSITIONS

Field of the Invention

The present invention relates to cleansing compositions. In particular it relates to mild, stable personal cleansing compositions with good skin feel attributes and foaming properties suitable for simultaneous cleansing and conditioning of the skin and/or the hair and which may be used, for example, in the form of foam bath preparations, shower products, skin cleansers, hand, face and body cleansers, shampoos, etc.

Background of the Invention

Mild cosmetic compositions must satisfy a number of criteria including cleansing power, foaming properties and mildness/low irritancy/good feel with respect to the skin, hair and ocular mucosae. Skin is made up of several layers of cells which coat and protect the keratin and collagen fibrous proteins that form the skeleton of its structure. The outermost of these layers, referred to as the stratum corneum, is known to be composed of 250 A protein bundles surrounded by 80 A thick layers. Hair similarly has a protective outer coating enclosing the hair fibre which is called the cuticle. Anionic surfactants can penetrate the stratum corneum membrane and the cuticle and, by delipidization destroy membrane integrity. This interference with skin and hair protective membranes can lead to a rough skin feel and eye irritation and may eventually permit the surfactant to interact with the keratin and hair proteins creating irritation and loss of barrier and water retention functions. Ideal cosmetic cleansers should cleanse the skin or hair gently, without defatting and/or drying the hair and skin and without irritating the ocular mucosae or leaving skin taut after frequent use. Most lathering soaps, shower and bath products, shampoos and bars fail in this respect.

Certain synthetic surfactants are known to be mild. However, a major drawback of most mild synthetic surfactant systems when formulated for shampooing or personal cleansing is poor lather performance compared to the highest shampoo and bar soap standards. Thus, surfactants that are among the mildest, such as sodium lauryl glyceryl ether sulfonate, (AGS), are marginal in lather. The use of known high sudsing anionic surfactants with lather boosters, on the other hand, can yield acceptable lather volume and quality but at the expense of clinical skin mildness. These two facts make the surfactant selection, the lather and mildness benefit formulation process and delicate balancing act.

Despite the many years of research that have been expended by the toiletries industry on personal cleansing, the broad mass of consumers remain dissatisfied by the skin feel, mildness and rinsing characteristics of present day synthetic based cleansing compositions. Many consumers prefer the skin feel and rinsing characteristics of soap cleansing products. However such soap based products cannot achieve the mildness attributes associated with mild synthetic surfactants. Moreover, a number of cationic and nonionic polymers which have been added to personal cleansing products for skin conditioning purposes are also found to be detrimental to skin feel, delivering a "slick" rather than soap-like feel on the skin.

In the formulation of soap-based toilet bar compositions it has been desirable to include free fatty acids in the composition. Such compositions are referred to as "superfatted" soaps. The free fatty acid contributes substantially to the lathering performance of the composition and also provides a mildness benefit in that it produces a lower pH product than is obtained with fully neutralized soap, and it has an emollient effect on the skin (see US Patent No 3,576,749, Megson et al, issued April 27th 1971).

Liquid soap-based skin cleansing products are well known in the art and generally use potassium neutralized fatty acids (see US Patent No 2,912,385, Golub et al, issued November 10th 1959). These have a higher solubility than the sodium soaps which are normally used in toilet bars. Free fatty acids can be incorporated into such compositions by using added solubility agents such as synthetic surfactants and/or hydrotropes.

Liquid soaps have been formulated with mixtures of saturated and unsaturated soaps to achieve highly concentrated, physically stable systems (see US Patent No 4,065,398, Brouwer, issued December 27th, 1977, and US Patent No 2,655,480, Spitzer et al, issued October 13th 1953).

There is still a need, however, for personal cleasning products which deliver improved soap-like skin feel characteristics, which at the same time are mild and do not dehydrate the skin. It would also be desirable to provide personal cleansing products which exhibit superior rinse-off, lather and product stability benefits.

It is therefore a primary object of the present invention to provide personal cleansing compositions having improved in-use and post-use skin feel, lather and mildness characteristics.

It is also an object of the present invention to provide personal cleansing compositions having improved rinse-off and product stability characteristics.

It is a further object of the present invention to provide personal cleansing compositions comprising certain mixtures of neutralized and unneutralized fatty acids.

Summary of the Invention

The subject of the present invention is a mild, foam-producing cleansing product suitable for personal cleansing of the skin or hair and which may be used as foam bath and shower products, skin cleansers and shampoos etc. According to one aspect of the invention, there is provided a liquid personal cleansing composition comprising: a) from about 6% to about 20% by weight of a mixture of alkali metal or ammonium hydroxide neutralized fatty acid and organic base neutralized fatty acid in a weight ratio of from about 10: 1 to about

1 :1; b) from about 0.1 % to about 5% by weight of unneutralized fatty acid; c) from about 0.5% to about 20% by weight of a synthetic surfactant selected from anionic, nonionic, cationic, zwitterionic and amphoteric surfactants, and mixtures thereof; and d) water;

and wherein the weight ratio of neutralized fatty acid to unneutralized fatty acid is greater than about 2:1, and wherein the total fatty acid mixture has a Cj2 content of less than about 5% by weight.

The liquid personal cleansing compositions of the invention exhibit superior skin feel and rinsing benefits together with excellent lathering, stability, mildness, cleansing and conditioning characteristics.

All concentrations and ratios herein are by weight of the cleansing composition, unless otherwise specified. Surfactant chain lengths are also on a weight average chain length basis, unless otherwise specified.

Detailed Description of the Invention

The liquid personal cleansing compositions of the present invention comprise alkali metal or ammonium hydroxide neutralized fatty acid, organic base neutralized fatty acid, unneutralized fatty acid, synthetic surfactant and water.

The mixture of fatty acids used in the present invention preferably have a fatty acid C\2 content of less than about 5% by weight thereof. A low fatty acid C\2 content is desirable herein from the viewpoint of reduction in harshness and irritancy of the compositions, as well as for product stability purposes. They fatty acids used in the compositions of the invention preferably comprise a mixture of C14 saturated fatty acids and C16-C18 saturated and monounsaturated fatty acids in a weight ratio of from about 10:1 to about 1 :3, preferably from about 3:1 to about 1:2, more preferably from about 1.5: 1 to about 1 : 1.5.

The C 14 saturated fatty acids known as myristic acids can be obtained from synthetic sources, as well as from the hydrolysis of natural oils such as coconut oil and palm kernel oil. Completely pure saturated fatty acids of any particular chain length are very difficult to procure, and therefore it is contemplated within the present invention that the saturated fatty acids used herein can contain minor amounts of other fatty acids. For example, typical coconut oil fatty acids used as a source of C14 fatty acids will consist of about 15% Cg to C10 acids, about 48% C\2 acids, about 18% C 14 acids, about 9% Ci6 acids, about 2% Ci acids and about 8% Cig unsaturated acids. When purified, myristic acid will contain less than about 5% of other fatty acid chain lengths.

The Ci6~Cι saturated and monounsaturated fatty acids used herein can be derived from vegetable, animal or synthetic fatty acid sources. The C 16-C 1 g saturated and monounsaturated fatty acids used herein are preferably derived from tallow. The tallow used herein typically has the following carbon chain length distribution: 1% C12 saturated, 2-3% C 14 saturated, 22-26% Ci6 saturated, 2-3% C 6 monounsaturated, 2% C\η saturated,^' 18-25% Cig saturated, 40-46% Cig monounsaturated and 1-4%

Cig diunsaturated. The Ci6-Cιg fatty acids can also be derived from vegetable oils.

In one embodiment of the invention, a mixture of C14 saturated fatty acid and tallow fatty acid is used in the composition wherein the ratio of C14 saturated fatty acid:tallow is in the range from about 4:1 to about 1:4.

The compositions of the invention comprise a total of from about 6% to about 20%, preferably from about 8% to about 15%, by weight of neutralized fatty acid. The fatty acids herein are neutralized by alkali metal or ammonium hydroxide and organic base so as to give a mixture of alkali metal or ammonium hydroxide neutralized fatty acid and organic base neutralized fatty acid in a weight ratio in the range from about 10: 1 to about 1 :1, preferably from about 5:1 to about 2:1, and especially from about 3:1 to about 2: 1. The ratio of neutralized to unneutralized fatty acids in the compositions herein is greater than about 2:1, preferably greater than about 4: 1. For the purpose of describing the present invention, the amount of fatty acid in the compositions is expressed in terms of fatty acid, without regard to whether it is neutralized or unneutralized.

The neutralized fatty acids are obtained by neutralizing the fatty acids in a conventional manner. The alkali metal hydroxide used herein is preferably potassium hydroxide and the organic base is preferably triethanolamine. These neutralizing agents are preferred in the compositions herein from the viewpoint of improved lather, product stability, skin feel and rinsing characteristics.

The compositions herein also comprise from about 0.5% to about 20%, preferably from about 1% to about 15%, especially from about 5% to about 10% by weight of synthetic surfactant selected from anionic, nonionic, cationic, zwitterionic and amphoteric surfactants, and mixtures thereof. The compositions preferably comprise a mixture of anionic and amphoteric surfactants in a weight ratio of from about 10: 1 to about 1 :3, preferably from about 5:1 to about 1:3, and especially from about 3:1 to about 1 :2. Other preferred embodiments of the compositions of the invention comprise mixtures of anionic amphoteric and nonionic surfactants. The level of the individual anionic, cationic, zwitterionic, amphoteric and nonionic surfactant components, where present,is in the range from about 0.1% to about 15%, preferably from about 0.5% to about 10% by weight of the composition.

Suitable anionic surfactants for use herein include mild synthetic detergent surfactants such as ethoxylated alkyl sulfates, alkyl glyceryl ether sulfonates, methyl acyl taurates, fatty acyl glycinates, N-acyl glutamates, acyl isethionates, alkyl sulfosuccinates, alpha-sulfonated fatty acids, their salts and/or their esters, alkyl ethoxy carboxylates, acyl sarcosinates and fatty acid/protein condensates, and mixturesthereof. Preferably the alkyl and/or acyl chain lengths for these surfactants are Cg-C22. more preferably

Cio-Cig and especially C12-C14. Preferred for use herein from the viewpoint of optimum mildness and lathering characteristics are the C12-C14 acyl sarcosinates, and salts thereof.

Suitable amphoteric surfactants for use herein include:

(a) imidazolinium derivatives of formula [I]

2^H4^OR2 _/ CH, Z

N

wherein R is C7-C22 alkyl or alkenyl, R2 is hydrogen or CH2Z, each Z is independently CO2 or CH2 CO2M and M is H, alkali metal, alkaline earth metal, ammonium or alkanolammonium; and/or ammonium derivatives of formula [II]

C₂H₄OH R₁CONH(CH₂) ₂N⁺CH₂Z R₂

wherein Rl, R2 and Z are as defined above:

(b) aminoalkanoates of formula [III]

RlNH(CH2)_nC02M

iminodialkanoates of formula [IV]

RlN[(CH₂)_mC0₂M]2

and iminopolyalkanoates of formula [V]

Rl[N(CH₂)_p]q - N[CH₂C0₂M]₂ CH2CO2M

wherein n, m, p and q are numbers from 1 to 4, and Ri and M are independently selected from the groups specified above; and

(c) mixtures thereof.

Suitable amphoteric surfactants of type (a) are marketed under the trade names Miranol and Empigen and are understood to comprise a complex mixture of species. Traditionally, the Miranols have been described as having the general formula I, although the CTFA Cosmetic Ingredient Dictionary, 3rd Edition indicates the non-cyclic structure II, while the 4th Edition indicates yet another structural isomer in which R2 is O-linked rather than N-linked. In practice, a complex mixture of cyclic and non- cyclic species is likely to exist and both definitions are given here for sake of completeness. Preferred for use herein, however, are the non-cyclic species.

Examples of suitable amphoteric surfactants of type (a) include compounds of formula I and/or II in which R is CgH 7 (especially isocapryl), C9H19 and Ci 1H23 alkyl. Especially preferred are the compounds in which Ri is C9H19, Z is CO2M and R2 is H; the compounds in which Ri is Ci 1H23, Z is CO2M and R2 is CH2CO2M; and the compounds in which Ri is Ci 1H23, Z is CO2M and R2 is H.

In CTFA nomenclature, materials suitable for use in the present invention include cocoamphocarboxypropionate, cocoamphocarboxy propionic acid, and especially cocoamphoacetate and cocoamphodiacetate (otherwise referred to as cocoamphocarboxyglycinate). Specific commercial products include those sold under the trade names of Ampholak 7TX (sodium carboxy methyl tallow polypropyl amine), Empigen CDL60 and CDR 60 (Albright & Wilson), Miranol H2M Cone. Miranol C2M Cone. N.P., Miranol C2M Cone. O.P., Miranol C2M SF, Miranol CM Special (Rhόne- Poulenc); Alkateric 2CIB (Alkaril Chemicals); Amphoterge W-2 (Lonza Inc.); Monateric CDX-38, Monateric CSH-32 (Mona Industries); Rewoteric AM-2C (Rewo Chemical Group); and Schercotic MS-2 (Scher Chemicals).

It will be understood that a number of commercially-available amphoteric surfactants of the above type are manufactured and sold in the form of electroneutral complexes with, for example, hydroxide couterions or with anionic sulfate or sulfonate surfactants, especially those of the sulfated Cg-

Cig alcohol, Cg-Cig ethoxylated alcohol or Cg-Cig acyl glyceride types. Preferred from the viewpoint of mildness and product stability, however, are compositions which are essentially free of (non-ethoxylated) sulfated alcohol surfactants. Note also that the concentrations and weight ratios of the amphoteric surfactants are based herein on the uncomplexed forms of the surfactants, any anionic surfactant counterions being considered as part of the overall anionic surfactant component content.

Examples of preferred amphoteric surfactants of type (b) include N-alkyl polytrimethylene poly-, carboxymethylamines sold under the trade names Ampholak X07 and Ampholak 7CX by Berol Nobel and also salts, especially the triethanolammonium salts and salts of N-lauryl-beta-amino propionic acid and N-lauryl-imino-dipropionic acid. Such materials are sold under the trade name Deriphat by Henkel and Mirataine by Rhόne- Poulenc.

The compositions herein can also contain from about 0.1% to about 15%, more preferably from about 0.5% to about 10% of zwitterionic surfactant, especially an alkyl betaine or amidobetaine surfactant.

Betaine surfactants suitable for inclusion in the composition of the invention include alkyl betaines of the formula:

R₅R6R7N⁺(CH2)nC0₂M [VIII]

and amido betaines of the formula (IX) ^R6 R₅CON(CH₂)_mN (+) (CH₂)_nC0₂M

^R7

wherein R5 is C12-C22 alkyl or alkenyl, R$ and R7 are independently C 1 - C3 alkyl, M is H, alkali metal, alkaline earth metal, ammonium or alkanolammonium, and n and m are each numbers from 1 to 4. Preferred betaines include cocoamidopropyldimethylcarboxymethyl betaine, laurylamidopropyldimethylcarboxymethyl betaine and Tego betaine.

The compositions of the invention preferably also contain from about 0.1% to about 15%, preferably from about 0.5% to about 10% by weight of nonionic surfactant, especially an oil derived nonionic surfactant or mixture of oil derived nonionic surfactants. Oil derived nonionic surfactants are valuable in compositions according to the invention for the provision of skin feel benefits both in use and after use. Suitable oil derived nonionic surfactants for use herein include water soluble vegetable and animal-derived emollients such as triglycerides with a polyethyleneglycol chain inserted; ethoxylated mono and di-glycerides, polyethoxylated lanolins and ethoxylated butter derivatives. One preferred class of oil derived nonionic surfactants for use herein have the general formula (VI)

0 i |

RCOCH₂CH(OH) CH₂ (OCH₂CH₂)_nOH

wherein n is from about 5 to about 200, preferably from about 20 to about 100, more preferably from about 30 to about 85, and wherein R comprises an aliphatic radical having on average from about 5 to 20 carbon atoms, preferably from about 9 to 18 carbon atoms.

Suitable ethoxylated oils and fats of this class include polyethyleneglycol derivatives of glyceryl cocoate, glyceryl caproate, glyceryl caprylate, glyceryl tallowate, glyceryl palmate, glyceryl stearate, glyceryl laurate, glyceryl oleate, glyceryl ricinoleate, and glyceryl fatty esters derived from triglycerides, such as palm oil, almond oil, and corn oil, preferably glyceryl tallowate and glyceryl cocoate.

Suitable oil derived nonionic surfactants of this class are available from Croda Inc. [New York, USA] under their Crovol line of materials such as Crovol EP40 [PEG 20 evening primrose glyceride], Crovol EP70 [PEG 60 evening primrose glyceride], Crovol A-40 [PEG 20 almond glyceride], Crovol A-70 [PEG 60 almond glyceride], Crovol M-40 [PEG 20 maize glyceride], Crovol M-70 [PEG 60 maize glyceride], Crovol PK-40 [PEG 12 palm kernel glyceride], and Crovol PK-70 [PEG 45 palm kernel glyceride] and under their Solan range of materials such as Solan E, E50 and X polyethoxylated lanolins and Aqualose L-20 [PEG lanolin alcohol] available from Westbrook Lanolin. Further suitable surfactants of this class are commercially available from Sherex Chemical Co. [Dublin, Ohio, USA] under their Varonic LI line of surfactants. These include, for example, Varonic LI 48 [polyethylene glycol (n=80) glyceryl tallowate alternatively referred to as PEG 80 glyceryl tallowate], Veronic LI 2 [PEG 28 glyceryl tallowate], Varonic LI 420 [PEG 200 glyceryl tallowate], and Varonic LI 63 and 67 [PEG 30 and PEG 80 glyceryl cocoates]. Other vegetable-derived emollients suitable for use herein are PEG derivatives of corn, avocado, and babassu oil as well as Softigen 767 [PEG(6) caprylic/capric glycerides].

Also suitable for use herein are nonionic surfactant derived from composition vegetable fats extracted from the fruit of the Shea Tree [Butyrospermum Karkii Kotschy] and derivatives thereof. This vegetable fat, known as Shea Butter is widely used in Central Africa for a variety of means such as soap making and as a barrier cream, it is marketed by Sederma [78610 Le Perray En Yvelines, France]. Particularly suitable are ethoxylated derivatives of Shea butter available from Karlshamn Chemical Co. [Columbos, Ohio, USA] under their Lipex range of chemicals, such as Lipex 102 E-75 [ethoxylated mono, di-glycerides of Shea butter]. Similarly, ethoxylated derivatives of Mango, Cocoa and Illipe butter may be used in compositions according to the invention. Although these are classified as ethoxylated nonionic surfactants it is understood that a certain proportion may remain as non-ethoxylated vegetable oil or fat. Other suitable oil-derived nonionic surfactants include ethoxylated derivatives of almond oil, peanut oil, rice bran oil, wheat germ oil, linseed oil, jojoba oil, oil of apricot pits, walnuts, palm nuts, pistachio nuts, sesame seeds, rapeseed, cade oil, corn oil, peach pit oil, poppyseed oil, pine oil, castor oil, soybean oil, avocado oil, safflower oil, coconut oil, hazlenut oil, olive oil, grapeseed oil, and sunflower seed oil.

Oil derived nonionic surfactants highly preferred for use herein from the viewpoint of optimum mildness and skin feel characteristics are PEG 60 evening primrose triglycerides; PEG 55 lanolin polyethoxylated derivatives and PEG 6 Cg-Cio glycerides.

The compositions of the invention may also include an insoluble perfume or cosmetic oil or wax or a mixture thereof at a level up to about 10%, preferably up to about 3% by weight wherein the oil or wax is insoluble in the sense of being insoluble in the product matrix at a temperature of 25°C. Addition of such oils or waxes can provide emolliency, mildness and rinsibility characteristics to personal cleansing compositions according to the invention. It is a feature of the invention, however, that compositions having excellent emolliency and mildness together with desirable physical attributes [clarity etc.] can be delivered which are essentially oil-free, ie which contain less than about 1%, preferably less than 0.5% by weight of an added oil phase. Physically, preferred compositions of this type take the form of an optically-clear solution or microemulsion. In compositons including an additional perfume or cosmetic oil or wax, preferably the weight ratio of nonionic surfactant to added oil is at least about 1:2, more especially at least about 3:1.

Suitable insoluble cosmetic oils and waxes for use herein can be selected from water-insoluble silicones inclusive of non-volatile polyalkyl and polyaryl siloxane gums and fluids, volatile cyclic and linear polyalkylsiloxanes, polyalkoxylated silicones, amino and quaternary ammonium modified silicones, rigid cross-linked and reinforced silicones and mixtures thereof, C1-C24 esters of Cg-C30 fatty acids such as isopropyl myristate, myristryl myristate and cetyl ricinoleate, Cg-C30 ester of benzoic acid, beeswax, saturated and unsaturated fatty alcohols such as behenyl alcohol, hydrocarbons such as mineral oils, petrolatum, squalane and squalene, polybutene, fatty sorbitan esters [see US-A-3,988,255, Seiden, issued October 26th 1976], lanolin and oil-like lanolin derivatives, animal and vegetable triglycerides such as almond oil, peanut oil, wheat germ oil, rice bran oil, linseed oil, jojoba oil, oil of apricot pits, walnuts, palm nuts, pistachio nuts, sesame seeds, rapeseed, cade oil, com oil, peach pit oil, poppyseed oil, pine oil, castor oil, soybean oil, avocado oil, safflower oil coconut oil, hazelnut oil, olive oil, grapeseed oil, and sunflower seed oil, and C1-C24 esters of dimer and trimer acids such as diisopropyl dimerate, diisostearylmalate, diisostearyldimerate and triisostearyltrimerate.

The compositions according to the present invention also include in preferred embodiments a skin conditioning cationic or nonionic polymer. The polymeric skin conditioning agent is preferably present at a level from about 0.01% to about 5%, preferably from about 0.04% to about 2% and especially from about 0.05% to about 1% by weight.

Suitable polymers are high molecular weight materials [mass-average molecular weight determined, for instance, by light scattering, being generally from about 2,000 to about 5,000,000, preferably from about 5,000 to about 3,000,000, more preferably from 100,000 to about 1,000,000].

Representative classes of polymers include cationic polysaccharides; cationic homopolymers and copolymers derived from acrylic and/or methacrylic acid; cationic and nonionic cellulose resins; cationic copolymers of dimethyldiallylammonium chloride and acrylic acid cationic homopolymers of dimethyldiallylammonium chloride; cationic polyalkylene and ethoxypolyalkylene imines; quatemized silicones, and mixtures thereof.

By way of exemplification, cationic polymers suitable for use herein include cationic guar gums such as hydroxypropyl trimethyl ammonium guar gum [d.s. of from 0.11 to 0.22] available commercially under the trade names Jaguar C-14-S(RTM) and Jaguar C-386 FA.(RTM) and also Jaguar C-16(RTM), which contains hydroxypropyl substituents (d.s. of from 0.8-1.1) in addition to the above-specified cationic groups, and quatemized cellulose ethers such as those known under the CTFA name Polyquatemium 10 and available commercially under the trade names Ucare Polymer JR-30M, JR-400 and Celquat. Other suitable cationic polymers are homopolymers of dimethyldiallylammonium chloride available commercially under the trade name Merquat 100, copolymers of dimethyl aminoethylmethacrylate and acrylamide, copolymers of dimethyldiallylammonium chloride and acrylamide, available commercially under the trade names Merquat 550 and Merquat S, quatemized vinyl pyrrolidone acrylate or methacrylate copolymers of amino alcohol available commercially under the trade name Gafquat, for example, Polyquatemium 11 and 23, and polyalkyleneimines such as polyethylenimine and ethoxylated polyethylenimine.

The viscosity of the final composition [Brookfield RVT DCP, 1 rpm with Cone CP41 or CP52, 25°C, neat] is preferably at least about 500 cps. The viscositiy of the compositions are preferably in the range of from about 1,000 to about 50,000 cps, more preferably from about 2,000 to about 30,000 cps, and especially from about 5,000 to about 18,000 cps.

The cleansing compositions can optionally include other hair or skin moisturizers which are soluble in the cleansing composition matrix. The preferred level of such moisturizers is from about 0.5% to about 20% by weight. In preferred embodiments, the moisturizer is selected from:

1. water-soluble liquid polyols;

2. essential amino acid compounds found naturally occuring in the stratum comeum of the skin; and

3. water-soluble nonpolyol nonocclusives and mixtures thereof.

Some examples of more preferred nonocclusive moisturizers are glycerine, polyethylene glycol, propylene glycol, sorbitol, polyethylene glycol and propylene glycol ethers of methyl glucose [eg ethyl glucam E-20 and propylglucan P-10], polyethylene glycol and propylene glycol ethers of lanolin alcohol [eg Solulan-75], sodium pyrrolidone carboxylic acid, L- proline, guanidine, pyrrolidone, hydrolyzed protein and other collagen- derived proteins, aloe vera gel and acetamide MEA and mixtures thereof. Of the above, glycerine is highly preferred. A number of additional optional materials can be added to the cleansing compositions each at a level of from about 0.1% to about 2% by weight. Such materials include proteins and polypeptides and derivatives thereof; water-soluble or solubilizable preservatives such as DMDM Hydantoin, Germall 115, methyl, ethyl, propyl and butyl esters of hydroxybenzoic acid, EDTA, Euxyl [RTM] K400, natural preservatives such as benzyl alcohol, potassium sorbate and bisabalol; sodium benzoate and 2- phenoxyethanol; other moisturizing agents such as hyaluronic acid, chitin and starch-grafted sodium polyacrylates such as Sanwet [RTM] IM-1000, IM-1500 and IM-2500 available from Celanese Superabsorbent Materials, Portsmith, VA, USA and described in US-A-4,076,663; solvents such as hexylene glycol and propylene glycol; anti-bacterial agents such as Oxeco [phenoxy isopropanol]; low temperature phase modifiers such as ammonium ion sources [eg NH4CI]; viscosity control agents such as magnesium sulfate and other electrolytes; colouring agents; pearlescers and opacifiers such as ethylene glycol distearate, Tiθ2 and Tiθ2-coated mica; perfumes and perfume solublilzers; and zeolites such as Valfour BV400 and derivatives thereof, Ca2⁺/M 2⁺ sequestrants such as polycarboxylates, amino polycarboxylar ti- polyphosphonates, amino polyphosphonates etc, fatty alcohols such as cetyl alcohol and antioxidants such as butylated hydroxy toluene. Antioxidants are used at a level of from about 0.001% to about 0.05%. Water is also present at a level preferably of from about 45% to about 93% preferably at least about 60% by weight of the compositions herein. The pH of the compositions is preferably from about 4 to about 10, most preferably from about 6 to about 10.

The compositions of the invention can also contain a hydrophilic gelling agent at a level preferably from about 0.01% to about 10%, more preferably from about 0.02% to about 2%, and especially from about 0.02% to about 0.5%. The gelling agent preferably has a viscosity [1% aqueous solution, 20°C, Brookfield RVT] of at least about 4000 mPa.s, more preferably at least about 10,000 mPa.s and especially at least 50,000 mPa.s. Suitable hydrophilic gelling agents can generality be described as water- soluble or colloidally water-soluble polymers, and include cellulose ethers [eg hydroxyethyl cellulose, methyl cellulose, hydroxypropylmethyl cellulose], polyvinylpyrrolidone, polyvinylalcohol, guar gum, hydroxypropyl guar gum and xanthan gum.

Preferred hydrophobic gelling agents herein, however, are acrylic acid/ethyl acrylate copolymers and the carboxyvinyl polymers sold by B.F. Goodrich Company under the trade mark of Carbopol resins. These resins consist essentially of colloidally water-soluble polyalkenyl polyether cross-linked polymer of acrylic acid cross-linked with from 0.75% to 2.00% of a crosslinking agent such as for example polyallyl sucrose or polyallyl pentaerythritol. Examples include Carbopol 934, Carbopol 940, Carbopol 950, Carbopol 980, Carbopol 951 and Carbopol 981. Carbopol 934 is a water-soluble polymer of acrylic acid cross-linked with about 1% of a polyallyl ether of sucrose having an average of about 5.8 allyl groups for each sucrose molecule. A most preferred polymer is Carbopol 951. Also suitable for use herein are hydrophobically-modified cross-linked polymers of acrylic acid having amphiphathic properties available under the trade name Carbopol 1382, Carbopol 1342 and Pemulen TR-1 [CTFA Designation; Acrylates/ 10-30 Alkyl Acrylate Crosspolymer]. a combination of the polyalkenyl polyether cross-linked acrylic acid polymer and the hydrophobically modified cross-linked acrylic acid polymer is also suitable and is preferred for use herein. The gelling agents herein are particularly valuable for providing excellent stability characteristics over both normal and elevated temperatures.

Neutralizing agents suitable for use in neutralizing acidic group containing hydrophilic gelling agents herein include sodium hydroxide, potassium hydroxide, ammonium hydroxide, monoethanolamine, diethanolamine and triethanolamine. The following Examples are illustrative of the personal cleansing compositions of the present invention.

EXAMPLES I TO V

I II UI IY Y

% % % % %

C14 fatty acid 4.5 4.6 5.7 4.5 4.0

Tallow fatty acid 4.5 4.6 5.7 4.5 6.0

Potassium hydroxide 2.26 2.26 2.40 2.25 2.30

Triethanolamine 0.82 0.82 1.00 0.82 0.95

Na Lauroyl Sarcosinate 3.0 3.0 4.0 3.0 4.0

Cocamidopropylbetaine 2.0 2.0 2.0 - 4.0

Cocoamphodiacetate 1.0 1.0 1.0 1.0 -

Polyquatemium 10 0.6 0.6 0.4 0.5 0.5

Softigen 767 3.0 1.0 - - 1.0

Myristyl Myristate - 2.0 - - -

Carbomer 1382 0.8 0.4 0.4 0.4 0.5

EGDS 1.5 1.0 1.0 1.0 1.0

Disodium EDTA 0.13 0.13 0.13 0.13 0.13

Phenoxyethanol 0.5 0.5 0.5 0.5 0.5

Perfume 1.0 1.0 1.0 1.0 1.0

Water -to 100- The compositions of the Examples contain about 1% of unneutralized fatty acids by weight of composition.

The compositions of the Examples are prepared as follows.

The thickening agent is added to the water in a sanitary agitated and jacketed stainless steel vessel. The contents of the vessel are vigorously agitated until the thickening agent is hydrated. The agitation is decreased and the vessel is heated to 65.6-71.1°C [150-160°F]. Pre-melted sources of the fatty acids are added to the vessel. The neutralizing agents are then added to the vessel at 65.6°C [150°F] with agitation in order to neutralize the fatty acids. At 65.6-71.1°C [150-160°F] the surfactants are added to the vessel with agitation, followed by the remaining ingredients. Finally, the resulting mixture is rapidly cooled to room temperature.

The product is then ready for packing.

The compositions of the Examples provide excellent mildness, product stability, lather, skin feel, moisturising, cleansing and rinsing characteristics.

Claims

What is claimed is:

1. A liquid personal cleansing composition comprising:

a] from about 6% to about 20% by weight of a mixture of alkali metal or ammonium hydroxide neutralized fatty acid and organic base neutralized fatty acid in a weight ratio of from about 10:1 to about 1:1;

b] from about 0.1% to about 5% by weight of unneutralized fatty acid;

c] from about 0.5% to about 20% by weight of a synthetic surfactant selected from the group consisting of anionic, nonionic, cationic, zwitterionic and amphoteric surfactants, and mixtures thereof; and d] water;

2. A composition according to Claim 1 wherein said fatty acid comprises a mixture of C14 saturated fatty acids and Cj6-Cι saturated and monounsaturated fatty acids in a weight ratio of from about 10:1 to about 1:3.

3. A composition according to Claim 1 wherein the alkali metal hydroxide is potassium hydroxide and the organic base is triethanolamine.

4. ⁱmposition according to Claim 1 additionally comprising from a : 0.01% to about 5% by weight of a polymeric skin conditioning a; : selected from the group consisting of cationic and nonionic p . - neric conditioning agents, and mixtures thereof, preferably w, - rein cationic and nonionic polysaccharides; cationic and nonionic hotr polymers and copolymers derived from acrylic and/or mX. acrylic acid; cationic and nonionic cellulose resins; cationic copolymers of dimethyldiallylammonium chloride and acrylic acid; cationic homopolymers of dimethyldiallylammonium chloride; cationic polyalkylene and ethoxypolyalkylene imines; quatemarized silicones, and mixtures thereof.

5. A composition according to Claim 4 wherein the polymeric skin conditioning agent has a mass average molecular weight in the range from about 2,000 to about 5,000,000, preferably between about 5,000 to about 3,000,000.

6. A composition according to Claim 1 wherein the composition has a viscosity [Brookfield RVT DCP, 1 rpm with Cone CP41 or CP52, 25°C, neat] in the range from 1,000 to 50,000cps.

7. A composition according to Claim 1 wherein the surfactant comprises a mixture of anionic and amphoteric surfactants in a weight ratio of from about 10:1 to about 1:3.

8. A composition according to Claim 1 comprising from about 0.1% to about 15% by weight of nonionic surfactant selected from ethoxylated oils or fats having the formula [VI]

RCOCH₂CH(OH)CH₂ (OCH₂CH₂)_nOH

wherein n is from about 5 to 200, preferably from about 20 to about 100, more preferably from about 30 to about 85, and wherein R comprises an aliphatic radical having an average from about 5 to 20 carbon atoms, preferably from about 9 to 20 atoms, more preferably from about 11 to 18 carbon atoms, most preferably from about 12 to 16 carbon atoms.

9. A composition according to Claim 1 wherein the anionic surfactant is selected from the group consisting of ethoxylated alkyl sulfates, alkyl glyceryl ether sulfonates, methyl acyl taurates, fatty acyl glycinates, alkyl ethoxy carboxylates, N-acyl glutamates, acyl isethionates, alkyl sulfosuccinates, alpha-sulfonated fatty acids, their salts and/or their esters, acyl sarcosinates and fatty acid/protein condensates, and mixtures thereof.

10. A composition according to Claim 7 wherein the anionic surfactant comprises a C -C22 acyl sarcosinate.

11. A composition according to Claim 7 wherein the amphoteric surfactant is selected from the group consisting of;

[a] imidazolinium derivatives of formula [I]

wherein Ri is C7-C22 alkyl or alkenyl, R2 is hydrogen or CH2Z, each Z is independently CO2 or CH2CO2M, and M is H, alkali metal, alkaline earth metal, ammonium or alkanolammonium; and/or ammonium derivatives of formula [II]

C₂H₄OH

R₁CONH ( CH₂ ) ₂N⁺CH₂ Z

^R2

wherein Rj, R2 and Z are as defined above: [b] aminoalkanoates of formula [III]

RlNH(CH₂)_nC02M iminodialkanoates of formula [IV]

RlN[(CH₂)mC0₂M]2 and iminopolyalkonoates of formula [V]

Rl[N(CH₂)_p]q - N[CH₂C0₂M]₂

I CH2C02M

wherein n, m, p and q are numbers from 1 to 4, and Rj and M are independently selected from the groups specified above; and

[c] mixtures thereof.

12. A composition according to Claim 11 wherein the amphoteric is selected from the group consisting of imidazolinium derivatives of formula I and ammonium derivatives of formula II.

13. A composition according to Claim 1 comprising from about 0.1% to about 15% by weight of a zwitterionic surfactant selected from alkyl betaines of the formula

R₅R6R7N+(CH2)nC0₂M [Vπη

and amido betaines of the formula [DC]

R₅CON (CH₂ ) _mN (+) (CH₂ ) _nC0₂M

wherein R5 is C12-C22 alkyl or alkenyl, R and R7 are independently C1-C3 alkyl, M is H, alkali metal, alkaline earth metal, ammonium or alkanolammonium, and n and m are aech numbers from l to 4.

14. A composition according to Claims 1 additionally comprising up to about 20% by weight of perfume or cosmetic oil.