SK154397A3 - Aqueous liquid cleansing composition containing fatty acid soaps - Google Patents

Abstract

An aqueous liquid cleansing composition comprising (a) at least one short chain C6-C10 fatty acid soap in combination with (b) at least one long chain C14-C22 fatty acid soap where the weight ration of (a) to (b) is within the range 1:20 to 5:1, and in which any C12 fatty acid soap is only present in low levels, is mild and provides good lather in use.

Description

Aqueous cleaning mixture

Technical field

The invention relates to aqueous liquid cleaning compositions containing specific fatty acid soaps. In particular, it relates to compositions suitable for cleansing the human skin and hair which comprise a combination of certain long and short chain fatty acid soaps. Such mixtures, in addition to being mild, provide good foaming.

BACKGROUND OF THE INVENTION

Traditionally, aqueous cleaning compositions are classified according to the amount of foam they produce in use; those that provide the largest volume of foam are considered to be the highest quality product. More recently, however, there has been a need for products which also exhibit good foaming / soaps and are mild to clean hair and skin.

The main problem associated with providing such products is that these two properties tend to be incompatible with each other. While very foaming surfactants are generally very hard, mild surfactants tend to provide insufficient foam.

In the past, attempts have been made to overcome these problems in the field of toilet soap, for example by the system described in GB 1295275, which involves the formation of a product containing tallow soap in combination with a C 8 -C 8 primary or secondary linear alkylsulfate and C1Q-C24 soap. fatty acid.

SUMMARY OF THE INVENTION

It has now been found that liquid cleaning compositions that exhibit good foaming and are mild can be formed using short chain fatty acid soap in conjunction with long chain fatty acid soap. It is surprising that a short-chain fatty acid soap that does not exhibit effective foaming when used alone may increase the foaming efficiency of the long-chain fatty acid soap.

Accordingly, the present invention provides an aqueous cleaning composition comprising (a) at least one short chain fatty acid soap selected from C 8 -C 8 fatty acid soaps;

(b) at least one long chain fatty acid soap selected from C ₄ -C 22 fatty acid soaps; and (c) water;

wherein the composition contains no more than 3% by weight of the aqueous fatty acid soap cleaning composition, contains no more than 15% by weight of the fatty acid soap, of the total amount of fatty acid soap, and the weight ratio (a): (b) is in the range 1:20 to 5: first

Preferably, the weight ratio (a) (b) is in the range of 1:20 to

1: 1st

The short-chain fatty acid soap is preferably a sodium or potassium salt or a substituted ammonium salt (e.g. triethanolamine), for example a fatty acid obtained from animal or plant sources, obtained by the distillation of the fatty acid. Preferably, the short chain fatty acid soap is a C 8 -C 8 fatty acid soap, most preferably a C 8 fatty acid soap.

The long-chain fatty acid soap is preferably a sodium or potassium salt or a substituted ammonium salt (e.g. triethanolamine), for example a fatty acid obtained from animal or plant sources, obtained by the distillation of the fatty acid. Preferably, the short-chain fatty acid soap is a C ₁₄ or C ₁₄ g, (C 18 g mono-unsaturated) fatty acid, most preferably C 8 fatty acid soap.

The total level of fatty acid soap in the composition should preferably be in the range of 1 to 40% by weight, preferably 5 to 30% by weight.

In a most preferred embodiment of the invention, the short chain fatty acid soap is a Cg material and the long chain soap is a Cg or material. Not only is this chain mixing system milder than the C12 fatty acid soap based compositions, but also exhibits comparable foaming efficiency. Low levels of fatty acid soap, not more than 3% by weight, preferably not more than 2% by weight of the total composition, and not more than 15% by weight of the total fatty acid soap content may be added to the mixed soap system. At this level of content, the presence of a C 1 - 2 fatty acid soap can further improve the foaming efficiency without adversely affecting the mildness of the composition.

The compositions of the present invention will preferably also contain a co-surfactant. The co-surfactant may be selected from any known surfactants suitable for topical application to the human body and selected from anionic, nonionic, zwitterionic and cationic surfactants and mixtures thereof. Mild surfactants, i. non-stratum corneum surfactants, the outer skin layer, are particularly preferred.

Preferred anionic surfactants include fatty acyl isethionates, alkyl ether sulfates, alkyl glyceryl ether sulfates, sulfosuccinates, taurates, sarcosinates, sulfoacetates, alkyl phosphates, alkyl phosphate ethers, acyl lactylates, alkyl glutamates and mixtures thereof.

Hard surfactants such as alkanesulfonates or alkylbenzenesulfonates are generally avoided.

Suitable nonionic surfactants include alkyl polysaccharides, lactobionamides, ethylene glycol esters, glycerol monoethers, polyhydroxamides (glucamides), ethoxylates of primary and secondary alcohols, especially C 8-20 aliphatic alcohols ethoxylated with an average of 1 to 20 moles of ethylene oxide.

Preferred zwitterionic surfactants are those having an alkyl or alkenyl group of 7 to 18 carbon atoms and conforming to the overall structural formula 4 cu:

OR ²

I

R ¹ - [- C-NH- (CH ₂ ) _m -] _η -Ν ⁺ -χ-γ

I

R ³ wherein R 1 is alkyl or alkenyl of 7 to 18 carbon atoms,

O Q

R and R are independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 3 carbon atoms m is 2 to 4 n is 0 or 1

X is C 1 -C 3 alkylene optionally substituted with hydroxyl, and

Y is -CO ₂ or -SO 3 ^-

Zwitterionic surfactants of the above general formula include simple betaines of the formula:

r ¹ -n ⁺ -ch ₂ co ₂ i ₃

R ³ and amido betaines of formula

R ²

I

R ¹ CONH (CH 2) m N ⁺ ₂ l ₃ -CH2C0

R ³ wherein m is 2 or 3.

In both formulas, R, R and R are as defined above. R ¹ may particularly be a mixture of C ^ ₂ and the alkyl groups derived from coconut so that at least half, preferably at least three quarters of the groups R have 10 to 14 carbon

O * 1 atoms. R and R are preferably methyl.

Another possibility is a sulfobetaine of the formula:

R ² r ¹ -n ⁺ - ( ^CH ₂ ) ₃ is ₃ 'or

R ¹ -CONH (CH 2) m N ⁺ - (CH 2) ₃ SO ₃ · wherein m is 2 or 3, or variants thereof, in which - (CH ₂ ) ₃ SO _{3 is} replaced by

-ch ₂ chch ₂ so ₃ io

In these formulas, R, R and R are as previously defined.

Compositions of the invention may include a structurant, ie, a material added to increase low shear viscosity, for example less than 1 sec ^- Y. Suitable materials include swellable clays, for example laponite; fatty acids and derivatives thereof, and in particular monoglyceride polyglycol ethers crosslinked polyacrylates, such as Carbopol (TM) (a polymer available from Goodrich); acrylates and copolymers thereof, polyvinylpyrrolidone and copolymers thereof; polyethyleneimines; salts such as sodium chloride or ammonium sulfate; sucrose esters; gelling agents; and mixtures thereof.

Of the clays, synthetic hectorite (laponite) clay used in conjunction with an electrolyte salt capable of causing clay thickening is particularly preferred. Suitable electrolytes include alkali metal and alkaline earth salts such as halides, ammonium salts and sulfates.

The compositions of the present invention may also contain a thickening agent, i.e., a material that maintains the viscosity of the composition, thereby increasing its shear rate during use. Suitable materials include crosslinked polyacrylates such as Carbopol (TM) (a polymer available from Goodrich); fatty acids and derivatives thereof, and in particular monoglyceride polyalcohol ethers of fatty acids; natural gums including alginates, guar, xanthan gum and polysaccharide derivatives including hydroxyethylcellulose, carboxymethylcellulose and hydroxypropylguar. rubber; propylene glycols and propylene glycol oleate; salts such as sodium chloride and ammonium sulfate; tallow glycerol esters; and mixtures thereof.

Further examples of structurants and thickeners are provided in the International Cosmetic Ingredient Dictionary, Fifth Edition, 1993, published by CTFA (The Cosmetic, Toiletry & Fragrance Association), which is incorporated herein by reference.

Examples of other additives that may be added to the compositions of the invention include opacifiers; preservatives such as parahydroxybenzoate esters; antimicrobials such as antioxidants such as butylhydroxytoluene; bactericides; wetting agents such as glycerol and sorbitol; waxes; plant extracts such as aloe vera, common hornbeam and black bases flower, dyes and perfumes.

The compositions of the invention may be formulated to wash the skin, for example, as a bath or shower gel; hand wash compositions; face wash compositions; pre- and after-shave preparations; and as skin rinsing and wiping preparations.

The compositions of the invention will generally be liquid liquids or semi-liquids, for example pastes, and preferably will have a viscosity n in the range of 100 to 100000 mPa · s, measured at a shear rate of 10 s -1 and 25 C in a Haake Rotoviscosimeter RV20.

DETAILED DESCRIPTION OF THE INVENTION

The invention is further illustrated by the following non-limiting examples.

In the examples

1. All fatty acids were of a purity greater than 99.5% by weight, ex Aldrich.

2. The betaine was coconut-amidopropylbetaine BDF-H, a 30% dispersion, ex Nippon Oils and Fats.

Examples 1 to 3

In this example, the effect of chain length on foaming efficiency was tested. The following preparations were prepared by co-melting the fatty acids. Potassium hydroxide was then slowly added in an amount to completely neutralize the fatty acids. Stirring was continued until the resulting mixture was homogeneous.

Table A

Example Weight / g KOH ^C 8 ^C 14 Water 1 5.61 4.81 7.61 to 500 ml at 25 ° C 2 5.61 7.21 11.42 to 500 ml at 25 ° C 3 5.61 9.61 15.23 up to 500 ml at 25 ° C

Table B

comparative Example Weight / g KOH fatty acid Water A 5.61 14.42 to 500 ml at 25 ° C B 5.61 17.22 to 500 ml at 25 ° C C 5.61 20.04 to 500 ml at 25 ° C D 5.61 22.84 up to 500 ml at 25 ° C

The foaming properties of the various mixtures were evaluated by a panel of twenty persons. Each panelist wore surgical gloves that were first washed with soap to remove all powder.

2.5 ml of the test mixture was dosed directly on dry gloves, and the panelist (male or female) rubbed each other's hands to form foam. The foam volume was measured by immersing the panelists' hands under a calibrated collection funnel.

The results obtained are shown in Table C, of which Comparative Examples A, B, C and D were performed with single chain length soaps.

Table C

Example Average string length and Foam volume / cm 1 10 45.3 2 11 46.2 3 12 47.6 A 8 0 B 10 0 C 12 39.8 D 14 30.7

The results show that the formulation containing only C-2 fatty acid soap (Example C) was the most foaming system of the comparative formulations. Example D (soap C1) of the penile was much less than the system, and Cg and C1-4 (Examples A and B) did not form a foam. The Cg / C14 mixtures produced a foam volume that was better than the foam volume of the pure C1 system. The results demonstrate that Cg soap enhances the foaming efficiency of the ^C 14 soap system ·

Example 4

In this example, tests were performed with fully prepared formulations.

The following preparations were prepared by co-melting the fatty acids. Potassium hydroxide was then slowly added in an amount to 97% neutralization of fatty acids. Stirring was continued until the resulting mixture was homogeneous. Betaine was then added to the soap solution with stirring. For those preparations containing sodium chloride, this was added as either a 25 wt. in distilled water or as crystals, in both cases they were mixed into the hot solution until completely dissolved and mixed. Water was then added to adjust the mixture to the correct concentration.

Table D

Example 4 Example E Example F Caprylic acid 1.70 - - Lauric acid - - 6.80 Myristic acid 8.50 10.20 3.40 Oleic acid 6.80 6.80 6.80 betaine 5.00 5.00 5.00 KOH 3.99 3.75 3.98 NaCl 1.5 - 1.00 Water up to 100% by weight

E and F are comparative examples

The foaming efficacy of these preparations was determined using the same method as described in Examples 1 to 3 except that 0.5 g of the test product was dosed on wet gloves.

The following results were obtained:

Table E

Example Foam volume / cm 2 4 66.6 E 49.3 F 56.1

The results demonstrate a gain in terms of foaming enhancement if the formulation contains C 8 fatty acid soap.

Examples 5 to 6

In this example, two formulations of the present invention and a comparative formulation (Example F above) were used without the Cg component (complete composition below) for skin wash. The viscosities of formulations 5 and 6 were adjusted with sodium chloride and their viscosity was similar to that of the comparative formulation of Example F.

Table F

Example 5 Example 6 Example F Caprylic acid 1.70 1.53 - Lauric acid - 1.00 6.80 Myristic acid 8.50 7.66 3.40 Oleic acid 6.80 6.80 6.80 betaine 5.00 5.00 5.00 KOH 3.99 4.00 3.98 NaCl 1.70 1.70 1.00 Water up to 100% by weight

The skin mildness properties of the test products were evaluated using a block arrangement in a standardized Flex Vash test. The Flex Vash test procedure consists of a daily triple one-minute wash of the antecubital fossa (elbow bending space). This method is an exaggerated method designed to distinguish very mild products. The erythema response varies only slightly with fluctuations in temperature and humidity, making the procedure suitable for testing throughout the year.

About 25 panelists. The panelists' bending surfaces must be free from any skin symptoms (eczema, dryness, irritation, scratches or abrasions). Anyone taking antihistamines, anti-inflammatory drugs (more than 8 per week), topical or oral, or injectable cortisone on a regular basis was excluded from the study. 3 test products were assigned to the wash areas (left or right arm) using a block arrangement.

The evaluation was as follows, the panelist was instructed to moisten the left bending surface and sponge. 0.5 g of product was then applied to the sponge and the metered sponge was placed in the panelist's right hand. Then the paneler washed the left bending surface for exactly one minute. Then the bend of op12 was rinsed and tapped dry. This washing procedure was repeated on the right shoulder with the appropriate mixture. Thus, both arms were tested simultaneously. Washing with this procedure was repeated three times a day for 5 consecutive days, a total of 15 washes. The processing times were scheduled 1.5 hours apart. Each test site was evaluated just before washing and 4 hours after the third daily wash.

One trained evaluator evaluated the sites tested in a total of 20 evaluations. The rating scale was as follows:

without erythema

0.5 barely perceptible erythema slight spot erythema / no edema

1.5 mild / moderate erythema / with or without edema mild flowing erythema / with or without edema or blistering.

Each test site was treated with the prescribed method until a score of 2 or greater was achieved or 15 washes were completed. When a score of 2 or greater was reached, the bending treatment was discontinued. The final score was then transferred to all remaining ratings. The remaining bend was washed until either a score of at least 2 or 15 treatments was achieved, whichever was the first. In Examples 5 and 6 and in Comparative Example F, the final score, the cumulative 5-day response, is the sum of the total scores for the 20 panelist scores averaged for scores from all panelists. Thus, in theory, the average score could range from 0 to 30; the lower limit of the score indicates absolutely irritated skin, the score of 30 being the worst.

The following results were obtained:

Table G

Example Cumulative 5 day response 5 8.51 6 9.04 F 15.60

The results demonstrate that the compositions of the present invention are significantly milder than the comparative composition containing no C 8 fatty acid soap and containing more than 3% by weight C ₁₂ fatty acid soap. The results also show that the addition of a small amount (1% by weight) of the C ₁₂ fatty acid soap does not adversely affect product mildness.

Claims (7)

PATENT CLAIMS An aqueous cleaning composition comprising (a) at least one short-chain fatty acid soap selected from C 8 -C 8 fatty acid soaps; (b) at least one long chain fatty acid soap selected from C14-C22 fatty acid soaps; and (c) water; wherein the composition contains no more than 3% by weight of an aqueous C 6 fatty acid soap cleaning composition, no more than 15% by weight C 6 fatty acid soap of the total amount of fatty acid soap, and the weight ratio (a) (b) is in the range 1 : 20 to 5: 1. The cleaning composition of claim 1, further comprising a co-surfactant selected from anionic, nonionic, cationic, zwitterionic surfactants and mixtures thereof. 3. A cleaning composition according to claim 2 wherein the co-surfactant comprises zwitterionic surfactants selected from alkyl betaines, amidopropyl betaines, amidopropylsultains and mixtures thereof. A cleaning composition according to any one of claims 1 to 3, wherein the fatty acid soap (a) is selected from C 8 to C 8 fatty acids soaps and mixtures thereof. A cleaning composition according to any one of claims 1 to 3, wherein the fatty acid soap (b) is selected from C ₁₄ to C ₁₄ g soaps. fatty acids and mixtures thereof. The cleaning composition of any one of claims 1 to 5, further comprising a thickener. Use of an aqueous liquid composition for cleaning human skin and hair, wherein the aqueous liquid composition comprises (a) at least one short-chain fatty acid soap selected from C 8 -C 8 fatty acid soaps; (b) at least one long-chain fatty acid soap selected from C24-C22 fatty acid soaps; and (c) water; wherein the composition contains no more than 3% by weight of the aqueous fatty acid soap cleaning composition, contains no more than 15% by weight of the fatty acid soap of the total amount of fatty acid soap and the weight ratio (a): (b) is in the range 1:20 to 5: first