WO2015106929A1

WO2015106929A1 - Oil-in-water silicone emulsion composition

Info

Publication number: WO2015106929A1
Application number: PCT/EP2014/078687
Authority: WO
Inventors: Kenji Igarashi; Youichi Hirose
Original assignee: Wacker Chemie AG
Current assignee: Wacker Chemie AG
Priority date: 2014-01-17
Filing date: 2014-12-19
Publication date: 2015-07-23
Anticipated expiration: 2016-07-17
Also published as: JP2015134881A; JP6170444B2

Abstract

Provided is a stable oil-in-water emulsion of organopolysxloxane using γ-cyclodextrin as a surfactant, which is suitable for use in cosmetics, foods, and an antifoam. The oil-in-water emulsion composition comprinsing (A) an organopolysiloxane, (B) γ-cyclodextrin, and (C) water, and in the composition, (A) is contained in the amount of 20 to 70% by weight and the mass ratio of (B)/(C) is 1/50 to 1/5. The organopolysiloxane (A) may be an antifoam compound containing silica.

Description

DESCRIPTION

OIL-IN-WATER SILICONE EMULSION COMPOSITION Technical Field

[0001]

The present invention relates to an oil-in-water emulsion composition obtained by emulsifying an organopolysiloxane with a cyclodextrin .

Background Art

[0002]

An organopolysiloxane, so-called silicone , is converted into an oil-in-water emulsion, and is used for various applications. Silicone is converted into an oil-in-water emulsion when a subject for application of the silicone, such as antifoam application and cosmetics, is an aqueous solvent or when use of the silicone as it is or use of the silicone dissolved in an organic solvent is' not suitable. For such an oil-in-water emulsion of silicone, an ionic or nonionic surfactant is generally used in emulsification . However, when the oil-in-water emulsion of silicone is used for applications such as cosmetics and foods, or effluent treatment, a substance having low impact and load on the human and the environment is required to be used as a surfactant.

[0003]

Since a cyclodextrin is a cyclic oligosaccharide, the cyclodextrin is used for applications such as foods and cosmetics as a compound having no impact and load, and if any, very low impact and load on the human and the environment . An emulsified composition of silicone with a cyclodextrin has been also proposed . For example , Patent Literature 1 discloses an emulsified composition including a mixture of three types of cyclodextrin, including α- , β-, and γ-cyclodextrins , polyethylene glycol, and various oily components , and further discloses an oil-in-water emulsion using silicone as the oily component. This composition is restricted in terms of composition ratios since this composition necessarily contains polyethylene glycol. Further, polyethylene glycol has an effect of stabilizing an oil-in-water emulsion, but acts as a thickener. Therefore, the obtained composition is creamy, and the use of the composition is restricted.

[0004]

On the other hand, Patent Literature 2 discloses a composition obtained by emulsifying γ-cyclodextrin and a dimethylpolysiloxane with water. In this case, an emulsion in which a compound having the dimethylpolysiloxane encapsulated in γ-cyclodextrin is dispersed in water is obtained. Therefore, it is preferable that the amount of the dimethylpolysiloxane to be mixed be much smaller than that of γ-cyclodextrin . In this emulsion, silicone is not emulsified by γ-cyclodextrin .

Citation List

Patent Literature

[0005]

Patent Literature 1 : Japanese Patent Application Laid-Open No. Hei. 9-315937

Patent Literature 2 : Japanese Patent Application Laid-Open No. 2000-230078

Summary of Invention

Technical Problem

[0006]

It is an object of the present invention to provide a stable oil-in-water emulsion of an organopolysiloxane using γ-cyclodextrin as a surfactant .

Solution to Problem

[0007]

The present inventors have found that an oil-in-water emulsion of an organopolysiloxane is obtained by emulsifying an

organopolysiloxane and γ-cyclodextrin at specific respective concentrations. Thus the present invention has been completed. Accordingly, the present invention is as follows:

[1] An oil-in-water emulsion composition comprising (A) at least one organopolysiloxane, (B) at least one γ-cyclodextrin, and (C) water, wherein (A) is contained in an amount of 20 to 70% by weight and the weight ratio of (B) / (C) is 1/50 to 1/5.

[2] The emulsion composition as set forth in [1] , wherein the organopolysiloxane (A) has an unsubstituted hydrocarbon group as an organo group .

[3] The emulsion composition as set forth in [1] or [2] , wherein the organopolysiloxane (A) is contained in an amount of 40 to 70% by weight.

[4] The emulsion composition as set forth in any one of [1] to [3] , wherein the organopolysiloxane (A) is a dimethylpolysiloxane having a viscosity of 0.65 to 10,000 mPa-s at 25°C.

[5] The emulsion composition as set forth in any one of [1] to [4] , wherein the organopolysiloxane (A) contains silica.

[6] The emulsion composition as set forth in [5] , further comprising (D) a surfactant, and wherein the organopolysiloxane (A) is contained in an amount of 20 to 40% by weight.

Viscosity is always measured at 25°C as dynamic viscosity according to DIN53019.

Advantageous Effects of Invention

[0008]

The emulsion of an organopolysiloxane of the present invention has no impact and load, and if any, very low impact and load on the human and the environment, and has excellent storage stability although γ-cyclodextrin having low emulsification ability is used. Description of Embodiments

[0009]

Hereinafter, the present inventionwill be described indetail .

The organopolysiloxane as the component (A) of the present invention is an organopolysiloxane having an average composition represented by the below general formula (1) .

In the general formula (1) , R¹ may be the same or different in the molecule, and is selected from a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, a hydrogen atom, a hydroxyl group, and an alkoxy group; and a is a positive number of 1.0 to 3.0.

[0010]

R¹ in the general formula (1) is preferably an unsubstituted monovalent hydrocarbon group. Specific examples thereof may include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, and an octadecyl group; a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group; an aryl group such as a phenyl group; and an aralkyl group such as a 2 -phenylethyl group and a 2-phenylpropyl group. Among them, an alkyl group is preferred, and a methyl group is particularly preferred .

[0011]

WhenR¹ is a substitutedmonovalent hydrocarbon group, examples of substituent in the hydrocarbon group may include an amino group, an aminoalkyl group, a halogen atom, a nitrile group, and a polyoxyalkylene group. Examples of an alkoxy group may include a methoxy group, an ethoxy group, and a propyl group that have 1 to 3 carbon atoms .

[0012]

In the general formula, a represents an average number of R¹ to be bonded to the silicon atom of the polysiloxane, and is 1.0 to 3.0. The molecular structure of the organopolysiloxane having an average composition represented by the general formula (1) may have not only a linear chain structure but also a branched structure, and preferably has a linear chain structure . The organopolysiloxane of the present invention can be produced by a method known to those skilled in the art. Specific preferred examples of the

organopolysiloxane, or silicone may include

trimethylsiloxy-terminated dimethyl silicone, hydroxy-terminated dimethyl silicone, and methylhydrogensiloxane .

Trimethylsiloxy-terminated dimethyl silicone and

hydroxy-terminated dimethyl silicone are preferred.

[0013]

The viscosity of the organopolysiloxane represented by the general formula (1) at 25°C is 0.65 to 1 x 10⁴ mPa-s. When hexamethyldisiloxane that is the smallest unit of

dimethylpolysiloxane is used, the viscosity of the component (A) at 25°C is 0.65 mPa-s . When the viscosity is more than 1 x 10⁴ mPa-s, emulsification is made difficult and a stable emulsion is hardly obtained. The viscosity of the component (A) at 25°C is preferably 5 to 8 x 10³ mPa-s . The organopolysiloxane represented by the general formula (1) may be a mixture of an organopolysiloxane having a high viscosity and an organopolysiloxane having a low viscosity as long as the viscosity as a whole falls within the above-described range. The mixture may be rather preferred according to applications . This is because the mixture contains a larger amount of the organopolysiloxane component having a high degree of polymerization andahighviscosityas comparedwith the use of the organopolysiloxane having a single molecular weight distribution.

[0014]

The amount of the component (A) contained in the present invention is 20 to 70% by weight in the emulsion of the present invention. When the amount thereof is less than 20% by weight, a stable emulsion cannot be obtained. When it is more than 70% by weight, the viscosity unpreferably increases. The amount of the component (A) contained is preferably 40 to 70% by weight in terms of storage stability.

[0015]

The organopolysiloxane as the component (A) of the present invention may contain silica. In the present invention, an organopolysiloxane containing silica is known to those skilled in the art as a so-called silicone antifoam compound, and a silicone antifoam compound can be used as the component (A) entirely or in part .

[0016]

The silicone antifoam compound is not limited as long as it is produced by a method known to those skilled in the art. A dialkylpolysiloxane is usually used as the organopolysiloxane. A dialkylpolysiloxane is mixed with silica, and the mixture is heated and mixed in the presence or absence of alkali such as potassium hydroxide, to produce the silicone antifoam compound. As the dialkylsiloxane, a trimethylsiloxy- terminated dimethylsilicone , a hydroxy-terminated dimethylsilicone, or a dimethyl silicone containing a long-chain alkyl group having 6 to 22 carbon atoms is used. A mixture thereof is also used.

[0017]

When the component (A) contains silica, examples of the silica may include fine powders of fumed silica, calcined silica, precipitated silica, silica aerogel, quartz, and molten silica. Among them, fine powders of fumed silica, precipitated silica, and silica aerogel are preferred. The silica surface thereof may be hydrophobized with a trimethylsilyl group, or the like. Such silica needs to be a fine powder having a surface area of 5 to 300 m²/g, and preferably 50 to 300 m²/g.

The amount of silica contained in the component (A) is 1 to 50% by weight, and preferably 2 to 20% by weight.

[0018]

γ-Cyclodextrin as the component (B) of the present invention is a cyclic oligosaccharide having 8 glucose units linked that is synthesized by an enzyme reaction using starch as a raw material. As a cyclodextrin, -cyclodextrin having 6 glucose units linked and β-cyclodextrinhaving 7 glucose units linked are known inaddition toy-cyclodextrin. γ-Cyclodextrinhas the most excellent solubility to water among the three, and is digestible. Therefore, γ-cyclodextrin is preferred in terms of the object of the present invention to emulsify silicone with a cyclodextrin having no impact and load, and if any, very low impact and load on the human and the environment . In the present invention, as γ-cyclodextrin, those generally produced or sold can be used.

[0019]

The component (B) of the present invention needs to be used in an amount of 1 to 10% by weight relative to the entire composition and the weight ratio of the component (B) / water as the component (C) preferably falls within a range of 1/50 to 1/5. When the weight ratio of (B) / (C) is less than 1/50, it is difficult to obtain a stable emulsion. When it is more than 1/5, the object of the present invention to emulsify silicone with a cyclodextrin is impaired. The weight ratio of (B) / (C) is preferably 1/20 to 1/10.

[0020]

The water (C) in the present invention is not particularly limited, but ion exchanged water is preferably used. The pH thereof is preferably 2 to 12, and particularly preferably 4 to 10. Use of mineral water is not recommended. However, when mineral water is used, it is desirable that mineral water be used in combination with a metal deactivator, or the like.

[0021]

A method for producing the emulsion composition of the present invention is not particularly limited, and the emulsion composition can be produced by a known method. The above-described components can be mixed and emulsified with an ordinarily mixer suitable for the production of an emulsion, such as a homogenizer, a colloid mill, a homomixer, and a high-speed rotor/stator mixer, to produce the emulsion. The emulsification can be performed by a method of mixing and stirring all the components (A) to (C) to prepare an oil-in-water emulsion, or a method in which γ-cyclodextrin (B) and a small amount of water (C) are mixed and stirred in the organopolysiloxane (A) , to prepare a water- in-oil emulsion, and the remainder of water is added to the emulsion and stirred to prepare an oil-in-water emulsion. In terms of ease in adjustment of emulsion particle diameter and stability of the emulsion, the method of first preparing a water- in-oil emulsion and then preparing an oil-in-water emulsion is preferred.

[0022]

In the emulsion composition of the present invention, a surfactant (D) can be further used in combination. By using the surfactant (D) in combination, the stability of the emulsion emulsified using γ-cyclodextrin can be further improved. When the amount of the component (A) to be mixed is small, the effect thereof is significant . When a silicone antifoam compound containing silica is used as the component (A) , the amount of the component (A) to be mixed is small in many cases, and accordingly, the use of the surfactant (D) in combination is particularly effective . When the emulsion using the silicone antifoam compound as the component (A) is used for antifoam application in effluent treatment or the like, the emulsion used is diluted in many cases. Therefore, the use of the surfactant (D) in combination is also effective in terms of improved dilution stability. The amount of the surfactant used is equal to or smaller than the amount of γ-cyclodextrin as the component

(B) , and is 5 to 100 parts by weight relative to 100 parts by weight of γ-cyclodextrin. When the amount of the surfactant used is less than 5 parts by weight relative to the γ-cyclodextrin, an effect of improving dilution stability when using the silicone antifoam compound as the component (A) is not sufficient. When it is more than 100 parts by weight, the object of the present invention to emulsify silicone with γ-cyclodextrin is impaired regardless of presence or absence of a surfactant.

[0023]

The surfactant (D) to be used in combination is not particularly limited as long as it allows silicone to be emulsified. Any of an anionic surfactant , a cationic surfactant , an amphoteric surfactant , and a nonionic surfactant can be used. Since use of an ionic surfactant maybe limited according to the applicationof the silicone emulsion, the versatility of emulsion of the present invention can be increased by use of a nonionic surfactant. This is preferred.

[0024]

Examples of the anionic surfactant may include alkyl sulfate salts, alkenyl sulfate salts, polyoxyalkylene alkyl ether sulfate salts, polyoxyalkylene alkenyl ether sulfate salts , polyoxyethylene alkylphenyl ether sulfate salts, olefinsulfonate salts,

alkanesulfonate salts, alkylbenzenesulfonate salts, alkylnaphthalenesulfonate salts, alkyl diphenyl ether disulfonate salts, saturated or unsaturated higher fatty acid salts, polyoxyalkylene alkyl or alkenyl ether carboxylate salts, salts of a-sulfofatty acid esters , amino acid-type surfactants, phosphate alkyl ester type surfactants, and ethylene oxide or propylene oxide adducts thereof, sulfosuccinic acid-type surfactants , taurine-type surfactants, amide ether sulfate-type surfactants, alkyl phosphate salts, polyoxyethylene alkyl ether phosphate salts,

polystyrenesulfonate salts, naphthalenesulfonate formaldehyde condensates, aromatic sulfonate formaldehyde condensates, carboxylic acid macromolecules , and styrene-oxyalkylene acid anhydride copolymers. Among them, alkyl sulfate salts,

polyoxyalkylene alkyl ether sulfate salts, and

alkylbenzenesulfonate salts are preferred.

[0025]

Examples of the cationic surfactantmay include alkyl trimethyl ammonium salts, dialkyl dimethyl ammonium salts, alkoxypropyl trimethyl ammonium salts, alkyl dimethyl benzyl ammonium salts, polyoxyethylene alkyl dimethyl ammonium salts, dipolyoxyethylene alkyl methyl ammonium salts , tripolyoxyethylene alkyl ammonium salts , alkyl benzyl dimethyl ammonium salts, alkyl pyridinium salts, monoalkylamine salts, monoalkylamidoamine salts, sulfonium salts, and phosphonium salts . Examples of the amphoteric surfactant may include imidazoline compounds, alkyl dimethylamine oxides, alkyl dimethyl carboxybetaines , alkylamidopropyl betaines, alkylamidopropyl dimethyl carboxybetaines , alkylhydroxy

sulfobetaines , and alkyl carboxymethyl hydroxyethyl imidazolinium betaines .

[0026]

Examples of the nonionic surfactant may include

polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene alkyl esters, glyceryl fatty acid esters, polyglyceryl fatty acid esters, propylene glycol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters,

polyoxyethylene fatty acid esters, polyoxyethylene glycerol fatty acid esters, polyoxyethylene propylene glycol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene adducts of castor oil or hydrogenated castor oil, higher fatty acid alkanolamides , polyoxyethylene fatty acid amides, polyoxyethylene-modified organopolysiloxanes , and polyoxyethylene

polyoxypropylene-modified organopolysiloxanes. Among them, polyoxyalkylene alkyl ether, polyglycerol fatty acid esters, and sorbitan fatty acid esters are preferred. It is preferable that the polyoxyalkylene alkyl ethers be a polyoxyalkylene alkyl ether in which the polyoxyalkylene group is an alkylene having 2 and/or 3 carbon atoms and the alkyl group is a linear or branched alkyl having 8 to 20 carbon atoms. Specific examples of such

polyoxyalkylene alkyl ethers may include a polyoxyethylene decyl ether, a polyoxyethylene undecyl ether, a polyoxyethylene dodecyl ether, apolyoxyethylene tridecyl ether, apolyoxyethylene hexadecyl ether, and a polyoxyethylene octadecyl ether. A compound in which the polyoxyethylene group thereof is a copolymer of polyoxyethylene and polyoxypropylene may also be used.

[0027]

The emulsion composition of the present invention may include various additives that are usually used for cosmetics, toiletry products, foods, foodadditives , or anantifoam, suchas apHmodifier, a refreshing agent, a humectant, and a preservative, according to the application or the object as long as the object of the present invention is not impaired. Specific examples of the pH modifier may include organic acids such as acetic acid and lactic acid, organic amines such as 2 -hydroxyethyl amine and 2 -hydroxypropyl amine, and mineral salts such as sodium bicarbonate and sodium carbonate. Specific examples of the refreshing agent may include L-menthol, menthaoil, peppermint oil , camphor, thymol, spilanthol, and methyl salicylate. Specific examples of the humectant may include alkylglycines , sorbitol, raffinose, pyrrolidone carboxylate salts, lactate salts, hyaluronate salts, ceramides, trehalose, xylobiose, maltose, sucrose, glucose, a plant mucilaginous polysaccharide and derivatives thereof, a water-soluble chitin, chitosan, pectin, a glycosaminoglycan and salts thereof such as chondroitin sulfate and salts thereof, amino acids such as glycine, serine, threonine, alanine, aspartic acid, tyrosine, valine, leucine, arginine, glutamine, and proline, and salts thereof, glyco-amino acid compounds such as an aminocarbonyl reactant , plant extracts of aloe, horse chestnut, etc., urea, uric acid, ammonia, and glucosamine. Specific examples of the preservative may include sodium hypochlorite, sorbicacid, otassium sorbate, salicylic acid, sodium salicylate, benzoic acid, sodium benzoate , parabens, isothiazoline compounds, and phenoxyethanol .

[0028]

When a thickener is used in combination in the emulsion composition of the present invention, the viscosity of the emulsion obtained canbe adjusted, and the stabilityand the dilution stability of the emulsion can be improved. As the thickener, a synthetic water-soluble macromolecule such as carboxymethyl cellulose and polyoxyethylene glycol or a water-soluble macromolecule derived from a natural product can be used. However, in consideration of the object of the present invention to emulsify silicone with γ-cyclodextrin that is considered to have no impact and load on the human and the environment, it is preferable that a natural product itself or a water-soluble macromolecule produced from a natural product by a fermentation method, which is approved to be used for foods or cosmetics, be used. Examples of such a water-soluble macromolecule derived from a natural product may include starch, gelatin, xanthan gum, guar gum, and carrageenan gum. When such a thickener is used in the emulsion of the present invention, the thickener may be dissolved in a water phase during an emulsification process for use, or an aqueous solution of the thickener may be added after emulsification . The thickener is usually used in an amount of 0.01 to 10 parts by weight relative to 100 parts by weight of water (C) .

Examples

[0029]

Hereinafter, Examples of the present invention will be described in detail, but the present invention is not limited to the following Examples. In Examples, a method for preparing an emulsified product and an evaluation method will be as follows. Part(s) represents part(s) by weight, and all values of viscosity were measured at 25°C.

[0030]

< Method for Preparing Emulsified Product and Evaluation of Emulsiflability >

An organopolysiloxane component, γ-cyclodextrin, and if necessary, a surfactant, and purified water in the same amount as that of γ-cyclodextrin were stirred with a four-bladed propeller at 500 rpm for 5 minutes, to prepare a water- in-oil emulsion. The water- in-oil emulsion was stirred with ULTRA-TURRAX T 50 basic shaft generator G45G manufactured by IKA at a rotation speed of 3,000 rpm for 5 minutes . The emulsion was diluted with the rest of purified water and stirred for 5 minutes to prepare an emulsified product. The resulting emulsified product became an oil-in-water emulsion by the emulsification operation. A case where the separation is not observed after the preparation is determined to be good in emulsiflability, and a case where immediately after the preparation, the separation of water and the concentration distribution of emulsion solid contents can be visually confirmed is determined to be poor in emulsiflability .

[0031]

< Storage Stability Test >

The prepared emulsified product of oil-in-water emulsion was placed in a 50-mL screw tube, and allowed to stand for 1 month. After that, the presence or absence of oil floating was visually confirmed. The absence of oil floating is determined to be good, and the presence of oil floating is determined to be poor.

< Dilution Stability Test >

Twenty grams of prepared emulsified product of oil-in-water emulsion was added to 180 g of purified water, and the mixture was sufficiently stirred and allowed to stand for 1 hour. After that, the presence or absence of separation of solid contents and purified water was visually confirmed. The absence of separation is determined to be good, and the presence of separation is determined to be poor.

[0032]

< Antifoaming Effect >

A mixed solution of 0.2 g of prepared emulsified product of oil-in-water emulsion, 8 g of sodium alkylsulfonate, and 200 g of purified water was prepared, and foamed for 1 minute with a beater. A time taken for elimination of bubbles was determined. Times taken for elimination of bubbles of 2 or more minutes, 1 or more minutes and less than 2 minutes, and less than 1 minute are determined to be a low antifoaming effect, a slightly high antifoaming effect, and a high antifoaming effect, respectively.

[0033]

< Examples 1 to 4 and Comparative Example 1 >

Fifty parts of dimethylpolysiloxanes having different viscosities or a mixture thereof was emulsified with 3 parts of γ-cyclodextrin (CAVAMAX (registered trademark) W8 available from Wacker Chemie AG, Munich, Germany) and 47 parts of purified water. The used dimethylpolysiloxanes are shown in Table 1. In Example 4, a mixture of dimethylpolysiloxanes was used, and the viscosity thereof was 8,000 mPa-s . In cases other than a case (Comparative Example 1) where dimethylpolysiloxane having a viscosity of 100,000 mPa-s was used, an oil- in-water emulsion was prepared and had storage stability.

[0034]

Table 1

[0035]

< Example 5 and Comparative Example 2 >

Fifty parts of dimethyIpolysiloxane having a viscosity of 350 mPa-s was used, the concentration of γ-cyclodextrin was changed, and emulsification was performed. As shown in compositions and evaluation results of stability of Table 2, in a case where 1.5 parts of γ-cyclodextrin was used, a stable oil-in-water emulsion was prepared, and in a case where 0.5 parts of γ-cyclodextrin was used, an oil-in-water emulsion was not obtained.

[0036]

< Example 6 and Comparative Example 3 >

An oil-in-water emulsion of Example 3 was prepared using dimethyIpolysiloxane having a viscosity of 350 mPa^s . To the emulsion, purified water was added and stirred to prepare an emulsion having a solid content concentration lower than that of the emulsion of Example 3. The compositions and evaluation results of stability the obtained emulsions are shown in Table 2

[0037]

Table 2

[0038]

< Comparative Examples 4 and 5 >

Fifty parts of dimethylpolysiloxane having a viscosity of 350 mPa-s was emulsified with 3 parts of a-cyclodextrin or β-cyclodextrin and 47 parts of purified water. In a case where α-cyclodextrin was used, the obtained emulsion was a water- in-oil emulsion, which was not a target oil-in-water emulsion. In a case where β-cyclodextrin was used, an emulsion was not produced.

[0039]

< Examples 7 to 9 and Comparative Example 6 >

A silicone antifoam compound including 95% by weight of dimethylpolysiloxane and 5% byweight of silica and having a viscosity of 3,500 mPa-s was emulsified with γ-cyclodextrin alone or in combination with a nonionic surfactant . As the nonionic surfactant , any of a polyoxyethylene alkyl ether, a polyglycereyl fatty acid ester, and a sucrose fatty acid ester was used. The nonionic surfactant used in combination, the composition of respective components, and evaluation results are shown in Table 3. When an antifoam compound was emulsified with only γ-cyclodextrin

(Comparative Example 6) , an oil-in-water emulsion was obtained, but the storage stability thereof was not sufficient . Whenanonionic surfactant in the same amount as that of the γ-cyclodextrin was used (Examples 7 to 9) , a stable emulsion was obtained, and the emulsion had dilution stability and a slightly high antifoaming effect.

[0040]

Table 3

-ANTIFOAM COMPOUND: including 95 parts by weight of dimethylpolysiloxane and 5 parts by weight of silica and having a viscosity of 3,500 mPa-s -POE STEARYL ETHER: polyoxyethylene stearyl ether (HLB 11)

-POLYGLYCEROL FATTY ACID ESTER: polyglycerol stearic acid ester (HLB 9) -SUCROSE FATTY ACID ESTER: sucrose stearic acid ester (HLB 9) Industrial Applicability

[0041]

The emulsion composition of the present invention is obtained by emulsifying silicone with γ-cyclodextrin that is considered to have no or very low impact and load on the human and the environment . Therefore, the emulsion composition is useful for an antifoam emulsion or a silicone emulsion for use in various foods or cosmetics .

Claims

1. An oil-in-water emulsion composition comprising:

(A) at leas tone organopolysiloxane;

(B) at least one γ-cyclodextrin; and

(C) water, wherein

(A) is contained in an amount of 20 to 70% by weight, and the weight ratio of (B) / (C) is 1/50 to 1/5.

2. The oil-in-water emulsion composition according to claim 1, wherein the organopolysiloxane (A) has an unsubstituted hydrocarbon group as an organo group .

3. The oil-in-water emulsion composition according to claim 1 or 2, wherein the organopolysiloxane (A) is contained in an amount of 40 to 70% by weight.

4. The oil-in-water emulsion composition according to any one of claims 1 to 3 , wherein the organopolysiloxane (A) is a dimethylpolysiloxane having a viscosity of 0.65 to 10,000 mPa^s at 25°C.

5. The oil-in-water emulsion composition according to any one of claims 1 to 4 , wherein the organopolysiloxane (A) contains silica .

6. The oil-in-water emulsion composition according to claim 5, further comprising (D) a surfactant, and wherein

the organopolysiloxane (A) is contained in an amount of 20 to 40% by weight.