GB2159408A

GB2159408A - Humectant

Info

Publication number: GB2159408A
Application number: GB08506618A
Authority: GB
Inventors: Seiji Noda; Tomoko Yasumasu
Original assignee: Lion Corp
Current assignee: Lion Corp
Priority date: 1984-03-30
Filing date: 1985-03-14
Publication date: 1985-12-04
Also published as: GB2159408B; FR2561915A1; JPH0557968B2; JPS60204708A; DE3511135A1; DE3511135C2; GB8506618D0

Abstract

A humectant comprises (A) a silicon compound having at least one silanol group in the molecule thereof and (B) a water-soluble polymer substance which is most suitably a mucopolysaccharide, protein, cellulose derivative, starch derivative or polyvinyl alcohol. This humectant exhibits an excellent humidity reserving effect and does not give a sticky feeling to the skin. It may be formulated into skin and hair cosmetics.

Description

SPECIFICATION Humectant Background of the Invention 1. Field of the Invention The present invention relates to a novel humectant. More specifically, it relates to a humectant exhibiting an excellent humidity reserving effect, which comprises a specific water-soluble silicon compound and a water-soluble polymer substance.

2. Description of the Related Art The skin is an interface between the living body and external ambiance and functions to protect the living body from, for example, humidity, sun rays, microorganisms, chemical substances, and mechanical or physical stimuli, and to maintain the homeostasis of the living bodies by appropriately adjusting the water vaporization from the living body. Stratum corneum is present on the outermost test of the skin and generally act to retain an appropriate amount of moisture therein. However, when the stratum corneum cannot retain an appropriate amount of moisture due to various external or internal factors, the skin drys out and becomes rough. As a result, the above-mentioned function of stratum corneum cannot be exhibited due to a decrease in the flexibility and extensibility of the skin.To counteract this phenomenon, it is necessary to supply or retain the moisture in the stratum corneum by an appropriate method or to prevent extensive evaporation of moisture from the stratum corneum. Accordingly, humectants are usually included in skin treatments and cosmetics.

For example, propylene glycol, glycerine, sodium pyrrolidone carboxylate, sodium lactate, and sorbitol are heretofore used in large amounts in cosmetics because these compounds have a good affinity to skin and give comfortable feeling during application. These conventional humectants have, however, disadvantages in that they are liable to give sticky feeling on the skin, and that moisture contained in the skin contrarily migrates to cosmetics containing those humectants, causing a drying of the skin in certain cases when the cosmetics are used under relatively low humidity conditions.

Recently, compounds having moisture preserving effects and contained in the skin, for example, mucopolysaccharides such as chondroitin sulfate, hyaluronic acid, mucoitin sulfate, charonin sulfate, collagen, and polypeptides have been found and used in, for example, cosmetics. However, these compounds still suffer from the disadvantages wherein the moisture preserving effects thereof are not necessarily satisfactory, although aging of the skin can be prevented to some extent.

Summary of the Invention Accordingly, the objects of the present invention are to eliminate the above-mentioned disadvantages of the conventional humectants and to provide a humectantthat does not give a sticky feeling to the skin and exhibits an excellent humidity reserving effect on the skin.

Other objects and advantages of the present invention will be apparent from the following description.

In accordance with the present invention, there is provided a humectant comprising (A) a silicon compound having at least one silanol group in the molecule thereof and (B) a water-soluble polymer substance.

Description of the Preferred Embodiment The silicon compounds usable as the component (A) in the humectant according to the present invention are those having at least one silanol group in the molecule thereof. Examples of such silicon compounds are monosilanol compounds having one silicon atom in the molecule thereof and polysilanol compounds having two or more silicon atoms in the molecule thereof, preferably, silanol compounds having 1 to 3 silicon atoms.More preferably, the silanol compounds usable as the component (A) in the present invention are those having the formula: RnSi(OH)4 (I) wherein R is an alkyl group having 1 to 6 carbon atoms, an aralkyl group having 6 to 11 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, provided that R may be the same or different when n is 2 or 3, and n is zero or an integer of 1 to 3, or those silanoates obtained by substituting a portion of the hydrogen atoms of the hydroxyl groups of the silanol compounds (I) with a basic substance such as alkali metals, alkaline earth metals, or amines.

Typical compounds having the above-mentioned general formula (I) are silanol, trimethyl silanol, dimethyl silanediol, methylethyl silanediol, methyl silanetriol, triethyl silanol, diethyl silanediol, ethyl silanetriol, di-n-propyl silanediol, diisopropyl silanediol, di-n-butyl silanediol, diisobutyl silanediol, di-tert-butyl silanediol, diallyl silanediol, triphenyl silanol, diphenyl silanediol, phenyl silanetriol, methyl cyclohexyl silanediol, and dicyclohexyl silanediol. Examples of the polysilanol compounds are tetramethyl disiloxane-1 ,3-diol, tetramethyl disilmethylene-1 ,3-diol, tetramethyl disilethylene-1 ,4-diol, and bis(methyivinyl) disiloxanediol.

The above-mentioned silanol compounds are generally unstable and readily polymerize, but are stabilized when used in combination with the above-mentioned component (B), i.e., the water-soluble polymer substances. The above-mentioned stabilization mechanism of the silanol compounds is not clearly understood, but it would seem that, without prejudice to the present invention, the silanol compounds are stabilized due to the formation of hydrogen bonds between SiOH in the silanol compounds and -OH groups and/or-NH2 groups in the water-soluble polymer substances.

The water-soluble polymer substances usable as the component (B) in the humectants according to the present invention are those having at least one hydroxyl group and/or at least one amino group. Examples of such water-soluble polymer substances are water-soluble biopolymer substances such as mucopolysaccharides and water-soluble proteins, cellulose derivatives, starch derivatives, and polyvinyl alcohols.

These water-soluble substances can be used alone or in any mixture thereof.

The above-mentioned mucopolysaccharides refer to mucopolysaccharides in a broad sense. Examples of such mucopolysaccharides are neutral mucopolysaccharides; acidic mucopolysaccharides such as hyaluronic acid, chondroitin, (chondroitin sulfate), and heparin; mucoproteins; glycoprotein; and glucolipids.

Examples of the water-soluble proteins are lipopeptides obtained from the condensation of the amino groups of protein hydrolyzates and the carboxyl groups of fatty acids, soluble collagen, soluble elastin, and soluble keratin.

Examples of the cellulose derivatives are carboxy-methyl cellulose (CMC), methyl cellulose (MC), hydroxyethyl cellulose (HEC), and hydroxypropyl cellulose (HPC).

Examples of the protein derivatives are those having a water-solubility higher than normal proteins, for example, partially hydrolyzed proteins, and the acetic acid derivatives, phosphoric acid derivatives, and hydroxyalkyl derivatives of proteins.

Examples of the polyvinyl alcohols are preferably those having a not very high degree of saponification (e.g., about 97 mole% or less), although the water-solubility thereof depends on the polymerization degree and saponification degree thereof.

Of the above-mentioned water-soluble polymer substances, the use of water-soluble biopolymer substances such as mucopolysaccharides and water-soluble proteins is especially preferable, since these polymer substances themselves have effective pharmaceutical effects on the skin and humidity preserving effects.

Although there is no specific limitation to the composition ratio of the silanol compounds (i.e., the component A) and the water-soluble polymer substances (i.e., the component B) in the present humectants, the preferable weight (ratio of the component (A) to the component (B) is from 1:10 to 10:1).

The humectants according to the present invention can be obtained by stabilizing the silanol compounds of the component (A) with the water-soluble polymer substance of the component (B). This stabilization may be effected by incorporating the silanol compounds into the aqueous solutions of the water-soluble polymer substances. However, since the silanol compounds are unstable and readily polymerize, the following method is preferably used in the production of the humectants according to the present invention.

That is, an aqueous solution of a silanoate compound, which is relatively stable, is first prepared, and then an aqueous solution of the above-mentioned water-soiuble polymer substance is added thereto.

Finally, the silanoate compound contained in the resultant solution is converted to the desired silanol compound with, for example, an H type cation exchange resin. Thus, the present humectant containing the stabilized silanol compound is obtained.

The above-mentioned aqueous solution of the silanoate compound can be prepared by, for example, a method disclosed in the Journal of The Chemical Society, 105, page 679. According to this method, a hydrocarbon substituted silane derivative containing halogen is used as a starting material. The starting silane derivative is hydrolyzed and hydrolyzate is recovered. The hydrolyzate thus recovered is then added to an aqueous solution of an alkali metal hydroxide in such a condition that at least one equivalent weight of a base (i.e., the alkali metal hydroxide) based on 1 gram atoms of the silicon atom is present in the resultant mixture.Alternatively, the desired aqueous silanoate compound solution can be prepared by adding a hydrocarbon substituted silane derivative containing halogen to an aqueous solution of an alkali metal hydroxide in which the base (i.e., the alkali metal hydroxide) is present in a total amount of the neutralizing equivalent weight based on the amount of the halogen present in the silanoate derivative and at least one equivalent weight based on 1 gram atom of the silicon atom.

The above-mentioned hydrocarbon substituted silane derivatives containing halogen usable as a starting material in the preparation of the aqueous solutions of the silanoate compounds include, for example, silicon tetrachloride, methyltrichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, dimethyldichlorosilane, chloromethyltrichlorosilane, chlorophenyltrichlorosilane, methylcyclo hexyldichlornsilane, and benzyltrichlorosilane, where an aqueous solution of a mono-, di- ortrisilanoate compound is prepared.

Although there is no critical limitation to the concentration of the components (A) and (B) in the aqueous solution thereof, the concentration is generally 0.001% to 10% by weight, preferably 0.01% to 5% by weight.

The humectants according to the present invention can be used, in addition to skin conditioning lotion and nutrient lotion; in aqueous cosmetic lotions such as astringent lotion, shaving lotion, body lotion, and liquid pack; creams such as nutrient cream, eye cream, body cream, hand cream, massage cream, cold cream, and emollient cream; liquid creams such as nutrient liquid cream, body liquid cream, neck liquid cream, and hand liquid cream; face packs; and the other skin cosmetics. Furthermore, the present humectants can be formulated into their cosmetics such as shampoo and rinse preparations.

When the present humectants are used in the above-mentioned application fields, the other necessary components can first be added to the humectants, or the humectants can be added in an appropriate amount to aqueous solutions, aqueous dispersions, or solid bases containing the other necessary components. Although there is no critical limitation to the formulation amount of the present humectants in the cosmetics, the present humectants are generally formulated into the cosmetics in an amount of 0.01% to 10% by weight, preferably 0.1% to 5% by weight, in terms of the total amount of the components (A) and (B), based on the total weight of the cosmetics.

EXAMPLES The present invention now will be further illustrated by, but is by no means limited to, the following Examples, in which all percentages are expressed on a weight basis unless otherwise specified.

EXAMPLE 1 Methyl trichlorosilane was hydrolyzed with distilled water in a beaker. The resultant precipitate was recovered, and then the equimolar amount of an aqueous sodium hydroxide solution was added thereto.

The reaction product was dissolved, while stirring, to obtain an aqueous silanoate (i.e., CH3Si(OH)2 ONa) solution having a silanoate concentration of 10%, in terms of silanol.

On the other hand, 100 ml of a 1% aqueous solution of purified hyaluronic acid (i.e., one kind of mucopolysaccharides available from Q.P.Co., Ltd., Japan) was prepared in another beaker. To this solution, 10 ml of the 10% aqueous silanoate prepared above was added and the pH of the resultant solution was adjusted to 6.5 with an H-type cation exchange resin. After the cation exchange resin was removed, the resultant solution was diluted to about 200 ml. Thus, a humectant was obtained. The solid concentration of the humectant thus obtained was about 1% as determined by vacuum drying.

EXAMPLE 2 Insoluble collagen derived from caifskin was dissolved in water with pepsin. Thus, a 4% aqueous solution of the purified water-soluble collagen was prepared.

To 80 ml of the solution obtained above, 10 ml of an aqueous solution of silanoate having a concentration of 10% in terms of silanol prepared in the same manner as in Example 1 was added. Then, the pH of the resultant solution was adjusted to 6.5 with an H-type cation exchange resin. The solution was then diluted with water to 100 ml to obtain a humectant. The solid concentration of the resultant humectant was 5% as determined by vacuum drying.

EXAMPLE 3 Two sheets, each 2 cmx2 cm square, of pigskin were prepared by cutting from a commercially available pigskin. Furthermore, various aqueous humectants shown in Table 1 were prepared.

A given amount of each humectant listed in Table 1 was coated on one surface of two sheets of the pigskin. The two sheets of the pigskin were allowed to stand at an ambient temperature for 24 hours in a desiccator maintained at a relative humiditity of 65% or 30%.

The water contents of the surfaces of the pigskin were then determined by impedance measurement.

The results were as shown in Table 2. The impedance was measured by using an impedance measurement device manufactured by l.B.S. Co., Ltd. The water content was determined from the impedance value by using a calibration curve. The average of the two sets of data was adopted.

TABLE 1 Sample No. Type of Humectant A Sodium pyrrolidone carboxylate (5% aqueous solution) B Glycerin (5% aqueous solution) C Sorbitol (5% aqueous solution) D Hyaluronicacid (1% aqueous solution) E Prepared in Example 1 (solid content=1 %) TABLE 2 Water content (%) of Pigskin Surface Sample No. 65% Relative Humidity 30% Relative Humidity A 66 15 B 29 7 C 20 4 D 42 29 E 68 66 As clearly shown in Table 2, the humectant stabilized with hyaluronic acid according to the present invention has an excellent humidity reserving effect superior to hyaluronic acid and other conventional humectants.

EXAMPLE 4 Two sheets, each 2 cmx2 cm square, of pigskin were prepared by cutting from a commercially available pigskin.

The two sheets of the pigskin prepared above were soaked at a room temperature for 5 minutes in an aqueous humectant solution having a solid control of 5% prepared in Example 2, a 5% aqueous collagen solution, or water. The two sheets of pigskin were then allowed to stand at a room temperature for 6 hours in a desiccator maintained at a relative humidity of 50%. The water content of the surfaces of the pigskin sheets was determined by measurement of the impedance in the same manner as in Example 3.

As a result, the water content was 75% when the humectant prepared in Example 2 according to the present invention was used. Contrary to this, the water contents were 55% in the case of the 5% aqueous collagen solution and 5% in the case of water.

EXAMPLE 5 A 5% aqueous solution of a mixture of dimethyl silanediol and chondroitin sulfate acid B (a weight ratio of 1:4) was prepared as a humectant in the same manner as in Example 2.

A cosmetic lotion having the following composition was formulated by using the humectant prepared above.

Ingredient Content (%) Dimethyl silenediol-chondroitin sulfuric acid B 5 Propyleneglycol Ethanol 6 Methyl p-hydroxybenzoate 0.1 Disodium hydrogen phosphate 0.06 Perfume 0.2 Purified water Balance When the resultant cosmetic lotion was applied to the skins of 20 women, the improvements in the moist and smooth feelings were observed with a level of significance of 1%.

EXAMPLE 6 A 1% aqueous solution of a mixture of ethyl silanetriol and hyaluronic acid (at a weight ratio of 1:1) was prepared as a humectant in the same manner as in Example 1.

An emollient cream having the following composition was formulated by using the humectant prepared above.

Ingredient Content (%) Ethyl silanetriol-hyaluronic acid 1 Liquid paraffin 6 Squalane 3 Cetyl palmitate 2 Cetyl alcohol 2 Stearic acid 2 Anti-oxidant 3 Purified water Balance When the emollient cream thus propared was applied to the skins of 20 women, the improvements in the moist and smooth feelings were observed with a level of significance of 1%.

EXAMPLE 7 A 1% aqueous solution of a mixture of phenyl silanetriol and hyaluronic acid (at a weight ratio of 1:1) was prepared as a humectant in the same manner as in Example 1.

A hair shampoo having the following composition was formulated by using the humectant prepared above. This hair shampoo exhibited an excellent humidity reserving effect on the hair.

Ingredient Content (%) Phenyl silanetriol-hyaluronic acid 1 Sodium C14-alpha-olefin sulfonate 10 Triethanolamine lauryl sulfate 5 Perfume 0.1 Purified water Balance EXAMPLE 8 A 2% aqueous solution of a mixture of trimethyl silanol-collagen (a weight ratio of 1:1.5) was prepared as a humectant in the same manner as in Example 2.

A hair rinse having the following composition was formulated by using the humectant prepared above.

This hair rinse exhibited an excellent humidity reserving effect on the hair.

Ingredient Content (%) Trimethyl silanol-collagen 2 Arquard 2HT* 2 Cetyl alcohol 3 Stearyl ethoxylate (ethylene oxide addition mole=5) 1 Perfume 0.1 Purified water Balance *cation surfactant available from Lion AKZO Co., Ltd.

Claims

1. A humectant comprising (A) a silicon compound having at least one silanol group in the molecule thereof and (B) a water-solution polymer substance.

2. A humectant as claimed in claim 1, wherein said silicon compound has 1 to 3 silicon atoms in the molecule thereof.

3. A humectant as claimed in claim 1, wherein said polymer substance has at least one hydroxyl group, at least one amino group, or a mixture thereof.

4. A humectant as claimed in claim 1, wherein said water-soluble polymer substance is a water-soluble biopolymer substance.

5. A humectant as claimed in claim 1, wherein said silicon compound has the formula: Rnsi(oH)4-n (I) wherein R is an alkyl group having 1 to 6 carbon atoms, an aralkyl group having 6 to 11 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms provided that R may be the same or differnt when n is 2 or 3, and n is zero or an integer of 1 to 3, or those silanoates obtained by substituting a portion of the hydrogen atoms of the hydroxyl groups of the silanol compounds (I) with a basic substance.

6. A humectant as claimed in claim 3, wherein said polymer substance is at least one member selected from the group consisting of mucopolysaccharides, water-soluble proteins, cellulose derivatives, starch derivatives, and polyvinyl alcohols.

7. A humectant as claimed in claim 1, wherein the weight ratio of the component (A) to the component (B) isfrom 1:10to 10:1.

8. A humectant according to Claim 1 substantially as hereinbefore described.

9. A humectant as hereinbefore described with reference to the Examples.