EP0633312A1 - Solid, transparent soap composition based on fatty acid salts, containing isopreneglycol - Google Patents

Abstract

Soap composition in the transparent solid cake (bar) form, having an improved hardness and an improved resistance to exudation (sweating). The composition contains, expressed by weight with respect to the total weight of the composition: a) from 25 to 40 % of a soap consisting of a salt of C10-C20 fatty acids or of their mixtures; b) from 2 to 50 % of isoprene glycol; c) from 0 to 48 % of a transparency agent, other than isoprene glycol, the total concentration of isoprene glycol and of transparency agent being between 25 and 50 %; and d) water in an amount less than or equal to 25 %. Application to the formation of bars of soap.

Description

The present invention relates to a solid, transparent soap composition based on fatty acid salts containing isoprene glycol.

Solid, transparent soap compositions are well known in the art. They generally consist, with or without alcohol, from soaps of tallow and / or coconut and / or castor fatty acids and transparency agents preferably chosen from polyols such as sugars, glycerin or glycols such as propylene glycol, ethylene glycol or mixtures of these.

In the case of solid soaps without alcohol, a soap content of less than 40%, in particular less than 20% in soaps of coconut fatty acids, is generally used to improve their transparency.

These compositions known in the cosmetic field can have the drawback of being not very foaming.

Application EP-A 0 336 803 describes a solid, transparent soap composition based on tallow fatty acid soap comprising at least one 1,2-alkanediol having improved foaming power. The transparency agents used in this composition are chosen from C₂-C₆ polyols such as more particularly glycerine, propylene glycol, and sorbitol or optionally urea as well as their mixtures.

US Pat. No. 4,165,293 describes a solid, transparent soap containing a sodium soap, an anionic or amphoteric surfactant or a C amp-C₆ diol, such as ethylene glycol, diethylene glycol, triethylene glycol, butylene glycol, pentamethylene glycol, hexylene glycol and dipropylene glycol, and preferably propylene glycol.

These solid, transparent soap compositions of the prior art, whether or not they contain a 1,2-alkanediol, have the drawback of wearing out very quickly, of softening in hot and humid atmospheres and of covering themselves of water droplets.

The wear rate of the soap is linked to its hardness. The higher the hardness of the soap, the less the soap wears out.

Therefore, it would be desirable to develop a solid, transparent soap composition, based on fatty acid soaps, which not only has a markedly improved moisture behavior, but also has increased hardness in order to decrease the speed. of wear of the soap.

Document JP 88/126811 describes the use as a moisturizing agent in creams, milks, lotions, cleansing creams, eau de toilette, foundations, shampoos, conditioners in cream, masks, lipsticks, eyeshadows and toothpaste, isoprene glycol or methyl-3-butylene-1,3 glycol.

The Applicant has surprisingly discovered that by introducing isoprene glycol into a solid soap composition based on fatty acid soaps, not only was there obtained a transparent solid soap composition having improved moisture behavior , but also an increase in the hardness of the soap was obtained and consequently a slower wear of the latter.

The present invention therefore relates to a detergent and foaming cosmetic composition in the form of a solid, transparent soap, based on soaps of fatty acids, water, optionally transparency agents and / or surface-active agents. active and containing isoprene glycol.

Another object of the invention is a washing process using the composition defined above.

Other objects of the invention will appear on reading the description and the examples which follow.

• a) de 25 à 40 % d'un savon constitué d'un sel d'acides gras en C₁₀-C₂₀ ou leurs mélanges;
• b) de 2 à 50 % d'isoprèneglycol;
• c) de 0 à 48 % d'un agent de transparence choisi parmi les diols en C₂-C₆ autre que l'isoprèneglycol, les polyols en C₃-C₆, l'urée et leurs mélanges, la concentration totale en b + c étant comprise entre 25 et 50 %; et
• d) de l'eau en une quantité inférieure ou égale à 25 %.

The composition in accordance with the invention is in the form of a transparent solid bread containing, expressed by weight relative to the total weight of the composition:

• a) from 25 to 40% of a soap consisting of a salt of C₁₀-C₂₀ fatty acids or their mixtures;
• b) from 2 to 50% of isoprene glycol;
• c) from 0 to 48% of a transparency agent chosen from C₂-C₆ diols other than isoprene glycol, C₃-C₆ polyols, urea and their mixtures, the total concentration of b + c being between 25 and 50%; and
• d) water in an amount less than or equal to 25%.

The soaps used in the present invention are well known in the art and are generally tallow fatty acid and / or coconut and / or castor oil soaps. Preferably, these soaps are chosen from sodium salts, in particular from sodium salts of C₁₆-C₂₀ fatty acids and sodium salts of C₁₀-C₁₄ fatty acids or mixtures thereof. They are preferably used in proportions of between 25 and 40%, in particular between 25 and 35% relative to the total weight of the composition.

A preferred embodiment of the invention consists in using a soap containing a proportion by weight of sodium salts of C₁₆-C₂₀ fatty acids of between 80 and 90% and a proportion by weight of sodium salts of C₁₀ fatty acids -C₁₄ between 10 and 20% compared to the total amount of soap.

The transparency agents, other than isoprene glycol, when they are used in the compositions of the present invention, are chosen from C₂-C₆ diols, C₃-C₆ polyols, urea and their mixtures. More particularly, propylene glycol, glycerin and sorbitol are recommended.

The amount of transparency agent used is equal to or less than 48% by weight relative to the total weight of the composition and is such that the sum of the concentration of transparency agent and the concentration of isoprene glycol is between 25 and 50 % by weight relative to the total weight of the composition.

As indicated above, the soap composition according to the invention contains from 2 to 50% by weight relative to the total weight of the isoprene glycol composition. Isoprene glycol not only acts in the composition as a transparency agent, but also improves the behavior in humidity and increases the final hardness of the composition. Preferably the soap composition according to the invention will contain from 5 to 30% of isoprene glycol and better still from 8 to 25% by weight.

The composition of the present invention can also, optionally, contain anionic, amphoteric, nonionic or cationic surfactants in order to improve the foaming power of the soap. These surfactants, when used in the compositions of the present invention, are present in proportions of less than or equal to 20% by weight relative to the total weight of the composition and preferably less than or equal to 10% in weight.

Preferably, between 4 and 8% by weight, relative to the total weight of the composition, of surfactant is used in the compositions of the present invention.

Among the anionic or nonionic surfactants which can be used in the present invention, mention may be made of those described in patent application EP-A-0 336 803 and in patent US-A-4 165 293.

Among the anionic surfactants, there may be mentioned the alkali salts, the ammonium salts, the amine salts, the amino alcohol salts, the magnesium salts of the following compounds: alkyl sulfates, alkyl ether sulfates, alkyl amido ether sulfates, alkylarylpolyethersulfates, monoglycerides sulfates; alkylsulfonates, alkylethersulfonates, alkylamide sulfonates, alkylarylsulfonates, olefin sulfonates, paraffin sulfonates, alkyl sulfosuccinates, alkyl ether sulphosuccinates, alkylamide sulphosuccinates, alkylsulphosuccinamates, alkyl sulphoacetates, alkyl ether phosphates, acyl sarcosinates, N-acyl taurates, acyl glutamates , and isethionates.

The alkyl or acyl radical of these different compounds generally consists of a carbon chain comprising from 10 to 20 carbon atoms.

It is also possible to use weakly anionic surfactants, such as polyamidealkylenated alkylamide or alkyl ether carboxylic acids, such as those comprising 2 to 50 ethylene oxide groups.

The nonionic surfactants are more particularly chosen from alcohols or α-diols or alkylphenols or polyethoxylated or polypropoxylated fatty acids with a fatty chain containing 8 to 18 carbon atoms, the number of groups ethylene oxide or propylene oxide being between 2 and 50 and the number of glycerol groups being between 2 and 30.

Mention may more particularly be made of copolymers of ethylene and propylene oxides; condensates of ethylene and propylene oxides on fatty alcohols; polyethoxylated fatty amides preferably having 2 to 30 moles of ethylene oxide; polyethoxylated fatty amines preferably having 2 to 30 moles of ethylene oxide; the fatty acid esters of sorbitan oxyethylenated preferably having 2 to 30 moles of ethylene oxide; sugar fatty acid esters, polyethylene glycol fatty acid esters, glycol fatty acid esters, amine oxides such as alkyl (C₁₀-C₁₄) amines or N-acylamidopropylmorpholine oxides , and alkyl (C₈-C₁₈) polyglycosides.

The preferred amphoteric or zwitterionic surfactants are the derivatives of aliphatic secondary or tertiary amines, in which the aliphatic radical is a linear or branched chain containing 8 to 18 carbon atoms and which contains at least one anionic water-solubilizing group carboxylate, sulfonate , sulfate, phosphate or phosphonate; alkyl (C₈-C₂₀) betaines, sulfobetaines, alkyl (C₈-C₂₀) amidoalkyl (C₁-C₆) betaines or alkyl (C₈-C₂₀) amidoalkyl (C₁-C₆) sulfobetaines.

Mention may also be made of alkylpeptides and alkylimidazolium betaines.

Among the amine derivatives, mention may be made of the products sold under the name "Miranol", such as those described in patents US-A-2,528,378 and 2,781,354 or classified in the CTFA dictionary, 3rd edition, 1982, under the names of Amphocarboxyglycinates or Amphocarboxypropionates.

The cationic surfactants are chosen from quaternary ammonium salts such as alkyl halides (C₈-C₂₂) trimethyl ammonium, dialkyl (C₈-C₂₂) dimethyl ammonium halides, alkyl halides (C₈- C₂₂) dimethyl hydroxyethyl ammonium.

It is also possible to add to the compositions according to the invention, 1,2-Ccan-C₁₈ alkanediols, as described in application EP-A-0 336803 to improve the foaming properties of soap. When used in the compositions of the present invention, these 1,2-C₁₀-C₁₈ alkanediols represent 10% by weight or less relative to the total weight of the composition. The 1,2-alkanediols which can be used in the present invention are saturated compounds with a linear chain with an even or odd number of carbon atoms which may contain from 10 to 18 and preferably from 10 to 14 carbon atoms. Dodecanediol-1,2 is the preferred alkanediol-1,2. ns can be obtained commonly by hydroxylation of the α-olefins or hydrolysis of the corresponding epoxides.

Preferably, 1,2-alkanediol is used in weight proportions equal to or less than 10%, generally between 3 and 10%, preferably between 4 and 8% and more particularly still between 5 and 7% relative to the weight total of the composition.

The compositions of the present invention may also contain antioxidants and sequestering or chelating agents, such as the tretrasodium salt of ethylene diamino tetraacetic acid, the tetrasodium salt of hydroxy-1 ethylidene diphosphonic acid. They are used in proportions of 0.1 to 0.5% by weight relative to the total weight of the composition.

The solid, transparent soap compositions according to the invention may also contain adjuvants which do not modify their transparency such as pearlescent agents, volatile or non-volatile silicones, organomodified or not, - in a weight content of less than 5% by weight , ceramides, perfluoropolyethers, skin conditioning agents such as polymers, aloe or mallow extracts, sunflower oil or collagen in a weight content of less than 2% by weight. The compositions in accordance with the invention may also contain active ingredients for the treatment of the skin such as anti-acne agents, anti-bacterial agents; they can also contain dyes, perfumes and other adjuvants usually used in cosmetics.

Solid, transparent soaps are prepared according to the invention in a conventional manner, by heating the fatty acids and the fatty substances to 75-80 ° C. to melt them and obtain a homogeneous medium. We then add isoprene glycol and optionally the other ingredients such as transparency agents, 1,2-alkanediols, surfactants, and other adjuvants. Then added, with stirring, the soda dissolved in water; stirring is continued for approximately 30 minutes. The soaps are poured in the form of breads at a temperature of 80-85 ° C., then allowed to cool to obtain the solid, transparent soaps, in the form of breads according to the invention.

Another object of the invention is a method of washing the skin, characterized in that a solid and transparent soap as defined above is applied to the skin.

The following examples illustrate the invention without, however, limiting it.

In the following examples, the penetration index of the soap was measured by measuring the degree of penetration to the 10th of a millimeter of a needle in the soap.

An electric Prolabo penetrometer with automatic timed release was used.

The tests were carried out on a bar of soap dried for 24 hours at room temperature (RT) at 25 ° C and after heating to 45 ° C for 30 hours.

The method of measuring the penetrometer index consists of placing the soap on the base of the penetrometer, then unlocking the head of the penetrometer from the support rod and lowering the head to bring the tip of the needle slightly above the soap surface. The needle is blocked in this position. Using a micrometric adjustment wheel, the head position is finely adjusted in height in order to bring the point of the needle just in contact with the surface of the soap.

Using a control button, a probe is brought into contact with the top of the support rod. Using the graduated dial of the device, and turning it, bring the 0 graduation in front of the needle. The trip time is preselected at 5 seconds. The penetrometer is then triggered and the depth, in tenths of a mm, of which the needle is inserted is read on the dial. The measurement is restarted at least 6 times by changing the position of penetration.

The soap penetration index is the average value of the measurements made.

The behavior of humidity is demonstrated by placing the bar of soap in an enclosure where an atmosphere of 80% relative humidity prevails and at ambient temperature, and the formation of water droplets on the surface of the surface is observed visually. bar of soap. We note the time after which these water droplets appear.

COMPARATIVE EXAMPLE

A solid, transparent bar of soap is prepared having the following composition: 50/50 mixture of stearic acid and palmitic acid 23.62 g Lauric acid 4.10 g Welded 4.26 g Propylene glycol 21.8g Sorbitol in 70% aqueous solution 10 gMA Glycerin 7.5 g Dodecanediol-1,2 5.65 g Antioxidant, sequestering agent, fragrance, coloring qs Alkyl (C₁₂-C₁₄) sodium ethersulfate at 2.2 EO in 70% aqueous solution 6.1 gMA Water qs 100g

EXAMPLE 1

A solid, transparent bar of soap is prepared according to the invention having the following composition: 50/50 mixture of stearic acid and palmitic acid 23.62 g Lauric acid 4.1g NaOH 4.26 g Isoprene glycol 21.8g Sorbitol in 70% aqueous solution 10 gMA Glycerin 7.5 g Dodecanediol-1,2 5.65 g Alkyl (C₁₂-C₁₄) sodium ethersulfate at 2.2 EO in 70% aqueous solution 6.1 gMA Antioxidant, sequestrant, fragrance, color qs Water qs 100g

The penetration index was measured at room temperature and at 45 ° C. for the composition of Example 1 and for the composition of the comparative example, as indicated above. The humidity behavior was also determined for these two compositions.

The results are shown in Table 1 below.

EXAMPLE 2

A solid, transparent bar of soap is prepared having the following composition: 50/50 mixture of stearic acid and palmitic acid 23.6g Lauric acid 4.1g NaOH 4.28 g Isoprene glycol 10.65 g Propylene glycol 10.65 g Sorbitol in 70% aqueous solution 9.65 gMA Glycerin 7.5 g Dodecanediol-1,2 5.65 g Alkyl (C₁₂-C₁₄) sodium ethersulfate at 2.2 EO in 70% aqueous solution 6.1 gMA Oxyethylenated stearyl alcohol with 20 EO sold by the company ICI under the name BRIJ 58 5 g Antioxidant, sequestrant, fragrance, coloring qs Water qs 100g

EXAMPLE 3

A solid, transparent bar of soap is prepared having the following composition: 50/50 mixture of stearic acid and palmitic acid 23.6g Lauric acid 4.1g NaOH 4.27 g Isoprene glycol 21.8g Sorbitol in 70% aqueous solution 10 gMA Glycerin 7.5 g Alkyl (C₁₂-C₁₄) sodium ethersulfate at 2.2 EO in 70% aqueous solution 10.5 gMA Antioxidant, sequestrant, fragrance, color qs Water qs 100g TABLE I Penetration index Time of appearance of water droplets on the soap surface after 30 hours at YOUR 45 ° C Comparative example 27/28 63 24 hours Example 1 25/26 55/56 six weeks

The solid, transparent, soap bar of Example 1 which differs from the bread of the comparative example in that the propylene glycol has been replaced by isoprene glycol clearly exhibits better behavior in humidity and greater hardness.

Claims (10)

Composition in the form of a transparent solid bread containing, expressed by weight relative to the total weight of the composition: a) from 25 to 40% of a soap consisting of a salt of C₁₀-C₂₀ fatty acids or their mixtures. b) from 2 to 50%, preferably 5 to 30% of isoprene glycol; c) from 0 to 48% of a transparency agent chosen from C₂-C₆ diols other than isoprene glycol, C₃-C₆ polyols, urea and their mixtures, the total concentration of b + c being included between 25 and 50%; and d) water in an amount less than or equal to 25%. Composition according to Claim 1, characterized in that the isoprene glycol represents from 8 to 25% by weight relative to the total weight of the composition. Composition according to any one of the preceding claims, characterized in that the transparency agent is chosen from propylene glycol, glycerin, sorbitol, and their mixtures. Composition according to any one of the preceding claims, characterized in that it additionally contains 20% by weight or less relative to the total weight of the composition of an anionic, amphoteric, nonionic or cationic surfactant. Composition according to Claim 4, characterized in that the surfactant is chosen from: alkaline salts, ammonium salts, amine salts, amino alcohol salts, magnesium salts of the following compounds: alkylsulphates, alkylethersulphates, alkylamidoethersulphates, alkylarylpolyethersulphates, monoglycerides sulphates; alkylsulfonates, alkylethersulfonates, alkylamides sulfonates, alkylarylsulfonates, olefins sulfonates, paraffins sulfonates, alkylsulfosuccinates, alkylethersulfosuccinates, alkylamides sulfosuccinates, alkylsulfosuccinamates, alkylsulfoacetates; alkyl etherphosphates, acylsarcosinates, N-acyltaurates, acylglutamates, isethionates, polyamidealkylenated alkylamide or carboxylic alkyl ether acids, alcohols or α-diols or alkylphenols or polyethoxylated or polypropoxylated fatty acids with a fatty chain containing 8 to 18 carbon atoms, the number of ethylene oxide or propylene oxide groups being between 2 and 50 and the number of glycerol groups being between 2 and 30, the derivatives of secondary or tertiary aliphatic amines in which the aliphatic radical is a linear or branched chain containing 8 to 18 carbon atoms and which contains at least one water-soluble anionic group carboxylate, sulfonate, sulfate, phosphate or phosphonate, the alkyls (C₈-C les) betaines, sulfobetaines, alkyl (C₈-C₂₀) amidoalkyl (C₁-C₆) betaines, alkyl (C₈-C₂₀) amidoalkyl (C₁-C₆) sulfobetaines, ethylpeptides, alkylimidazolium betaines, and quaternary ammonium salts. Composition according to any one of the preceding claims, characterized in that it also comprises 10% by weight or less relative to the total weight of the composition of a 1,2-C₁₀-C₁₈ alkanediol or of a mixture of these. Composition according to Claim 6, characterized in that the 1,2-alkanediol is 1,2-dodecanediol. Composition according to any one of the preceding claims, characterized in that it also contains adjuvants chosen from sequestering agents, pearling agents, volatile or non-volatile silicones, organomodified or not, skin conditioning agents, ceramides, extracts of aloe or mallow, sunflower oil, collagen, dyes or perfluoropolyethers. Composition according to any one of the preceding claims, characterized in that it contains active ingredients for the treatment of the skin. Process for washing the skin, characterized in that a cosmetic composition is applied to the skin in the form of a transparent solid bread as claimed in claims 1 to 9.