WO2018091220A1

WO2018091220A1 - Silicone emulsion composition

Info

Publication number: WO2018091220A1
Application number: PCT/EP2017/076621
Authority: WO
Inventors: Airi SENGOKU; Kenji Igarashi
Original assignee: Wacker Chemie Ag
Priority date: 2016-11-15
Filing date: 2017-10-18
Publication date: 2018-05-24
Also published as: JP2018080244A; JP6758161B2

Abstract

Provided is a silicone resin emulsion composition which has favorable long-term preservation stability and which does not cause adverse effects due to an organic surfactant when the composition is applied to a protective coating agent, a cosmetic product, and the like. The silicon resin emulsion composition includes: (A) 20 to 80 parts by mass of an organopolysiloxane having an average composition represented by general formula (1) : ⋅ R¹ _aSiO_(4-a)/2 (1) [wherein R¹s may be the same as or different from each other in a molecule, and are each a substituted or unsubstituted, saturated or unsaturated monovalent hydrocarbon group having 1 to 25 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a hydroxy1 group, an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom, and a is 0.3 or more and less than 2.0]; (B) 0.3 to 10 parts by mass of a silica particle having on a surface thereof a hydrophobized portion and a silanol group; and (C) water. In the composition, the silica particle (B) is disposed at an interface between an oil phase of an oil droplet formed from the organopolysiloxane (A) and an aqueous phase formed from the water (C).

Description

DESCRIPTION

SILICONE EMULSION COMPOSITION TECHNICAL FIELD

[0001]

The present invention relates to a silicone emulsion composition which does not contain an organic solvent or an organic surfactant and which is suitably used as a protective coating agent, cosmetics, a plastic additive, and the like for imparting water repellency, heat resistance, weather

resistance, scratch resistance, soil resistance, UV cutting, and impact resistance to various base materials.

In particular, the present invention relates to an emulsion of a silicone resin.

BACKGROUND ART

[0002]

A silicone resin having a three-dimensional siloxane backbone in combination with various fillers and organic resins is used in various use applications, for example, as a heat-resistant paint in a wide temperature range, a weather- resistant paint, a raw material for modifying a resin, an electrically insulating coating agent for the purpose of protecting various electronics components, and a binder for heat resistance and electrical insulation. Also, a silicone resin is widely used in the field of cosmetic materials for the purpose of, for example, protecting against external stimuli such as UV light and drying, and imparting water resistance .

[0003]

In general, a silicone resin is a powdery or flake- like raw material, and is dissolved in an organic solvent to be formulated to a paint and the like. However, from the

viewpoint of the ensurement of a safe working environment and the load on the environment, the dispersion medium is required to be changed from an organic solvent base to an aqueous base in recent years. Thus, a demand for an aqueous emulsion composition is increased.

Also, in the field of cosmetics, an organic solvent causes irritation to the skin. Therefore, a usable organic solvent is limited. Even a less irritating organic solvent such as mineral oil, which can be used in the cosmetic

applications, sometimes reduces the function of the skin and the growth of the cell when such a solvent is brought into contact with the skin. Accordingly, even in the field of cosmetics, there is similarly a demand for an emulsion

composition which does not contain an organic solvent.

Furthermore, when a resin is used in the form of powder as it is in various use applications, an emulsion composition is also required to contain no organic solvents or organic substances and has a favorable shape of particles and particle size distribution.

[0004]

Under such circumstances, for example, Patent Literature 1 discloses a silicone resin emulsion from which an organic solvent is removed by substituting a solvent component in an organic solvent solution of a silicone resin synthesized in an organic solvent, with a nonionic organic surfactant.

However, the use of an organic surfactant generally had various problems. For example, the long-term storage stability as an emulsion and the condition for formulating an end product were limited. Also, in industrial use applications such as a protective coating agent, physical properties were reduced by an organic emulsifier. Furthermore, in the cosmetic applications, which are to be directly applied on the skin, there was a possibility that irritation to the skin may be caused .

CITATION LIST PATENT LITERATURE

[0005]

Patent Literature 1: Japanese Patent Application Laid- Open No. 2014-31413

SUMMARY OF INVENTION TECHNICAL PROBLEM

[0006] The present invention has been made in view of the above- described circumstances. An object of the present invention is to provide a silicone resin emulsion composition which has favorable long-term storage stability and which does not cause negative effects due to an organic surfactant when it is applied to a protective coating agent, a cosmetic product, and the like.

SOLUTION TO PROBLEM

[0007]

As described above, any conventional techniques have not disclosed a specific method for obtaining a silicone resin emulsion which solves the above-described problems.

[0008]

The present inventors have intensively conducted studies for achieving the above-described object, and found that a silicone resin emulsion in which the surfaces of emulsion particles are coated with silica particles has excellent

properties in terms of the development of its use applications, thereby eliminating the limitation to its use applications.

[0009]

The present invention has been achieved on the basis of the above-described knowledge.

That is, an emulsion composition according to the present invention includes: (A) 20 to 80 parts by mass of an

organopolysiloxane having an average composition represented by general formula (1) ,

[wherein R^s may be the same as or different from each other in a molecule, and are each a substituted or unsubstituted, saturated or unsaturated monovalent hydrocarbon group having 1 to 25 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom, and a is 0.3 or more and less than 2.0] ; (B) 0.3 to 10 parts by mass of a silica particle having on a surface thereof a

hydrophobized portion and a silanol group; and (C) water, wherein the silica particle (B) is disposed at an interface between an oil phase of an oil droplet formed from the

organopolysiloxane (A) and an aqueous phase formed from the water (C) .

[0010]

It is preferable that the organopolysiloxane (A) be fluidized after the whole organopolysiloxane (A) has been homogenized .

[0011]

It is preferable that the residual rate of a silanol group after the silanol group on the surface of the silica particle (B) has been silylated be in the range of 50 to 95 mol% .

ADVANTAGEOUS EFFECTS OF INVENTION [0012]

The emulsion composition according to the present invention is an emulsion composition which includes a silicone resin as a base component. In the emulsion composition, the silica particle is disposed at the interface between an oil phase being the organopolysiloxane and an aqueous phase, without recourse to nonionic, anionic, cationic, and

amphoteric organic surfactants which are generally used.

The silica particle of the component (B) has appropriate compatibility with both an oil phase and an aqueous phase. Therefore, the silica particle can be disposed at the

interface between the oil phase and the aqueous phase to provide an oil-in-water emulsion with the aqueous phase as a continuous phase.

Accordingly, the emulsion can be stably used in a series of processes such as preparation and preservation of the emulsion, preparation and preservation when formulated to a protective coating agent, cosmetics, or the like, and

treatment in the end use applications.

[0013]

In this manner, the emulsion composition becomes in a favorable emulsion state. Therefore, when the emulsion composition according to the present invention is formulated to a protective coating agent or cosmetics and treated in the end use applications, various adverse effects due to an organic surfactant, such as instable coating, reduced heat resistance, reduced hardness, and stimuli to the skin, are not caused.

Also, since the emulsion composition is used as an

aqueous emulsion, it is advantageous in terms of safety and the environment .

Furthermore, the resin can be isolated from the emulsion more safely than in the system of dispersion in an organic solvent. In addition, the variations in particle size and the shape in the above-described emulsion state can also have favorable effects on resin powder. Therefore, the effects such as improved impact resistance and heat resistance can also be expected in use applications such as when the resin powder is formulated as powder to plastics.

DESCRIPTION OF EMBODIMENTS

[0014]

Hereinafter, the silicone resin emulsion composition according to the present invention will be described in detail.

[0015]

(Component (A) )

The organopolysiloxane of the component (A) according to the present invention is an organopolysiloxane having an

average composition represented by general formula (1) :

R¹ _aSiO₍₄._a)/2 (1)

[wherein R¹s may be the same as or different from each other in a molecule, and are each a substituted or

unsubstituted, saturated or unsaturated monovalent hydrocarbon group having 1 to 25 carbon atoms, a substituted or

unsubstituted aromatic group having 6 to 30 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom, and a is 0.3 or more and less than 2.0] .

R¹ bonded to a silicon atom in the component (A) is preferably a substituted or unsubstituted monovalent

hydrocarbon group having 1 to 13 carbon atoms.

a is a value which is involved in the order of a siloxane bond. When a is 2.0, the component (A) indicates a linear siloxane. Since a is less than 2.0 in the present invention, the component (A) is a resin. When a is 2.0 or more, the component (A) becomes an oil. Therefore, the object of the present invention, that is, favorable coating properties and properties as cosmetics, cannot be achieved. Also, when a is less than 0.3, although the component (A) is in the state of a resin, but is high-dimensional and nearly becomes glass. Thus, it becomes difficult to emulsify, and therefore is not

suitable for the purpose of the invention.

[0016]

Specific examples of the above-described organic group may include: an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a neopentyl group, a hexyl group, a 2 -ethylhexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and a dodecyl group; a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, a biphenyl group, and a naphthyl group; an aralkyl group such as a benzyl group, a phenylethyl group, a phenylpropyl group, and a methyl benzyl group; a nitrogen-containing hydrocarbon group

represented by -CH₂-CH₂-CH₂-N_2i -CH₂-CH₂-CH₂-NH (CH₃) , -CH₂-CH₂- CH₂-N (CH₃) ₂, -CH₂-CH₂-NH-CH₂-CH₂-NH₂, -CH₂-CH₂-CH₂-NH (CH₃) , -CH₂- CH₂-CH₂-NH-CH₂-CH₂-NH₂ , -CH₂-CH₂-CH₂- H-CH₂-CH₂-N (CH₃ ) ₂ , -CH₂-CH₂- CH₂-NH-CH₂-CH₂-NH(CH₂CH₃) , -CH₂-CH₂-CH₂-NH-CH₂-CH₂-N (CH₂CH₃ ) ₂ , and -CH₂-CH₂-CH₂-NH-CH₂-CH₂-NH(cyclo-C_eHn) ; and a substituted hydrocarbon group such as a chloromethyl group, a 2-bromoethyl group, a 3 , 3 , 3 -trifluoropropyl group, a 3 -chloropropyl group, a chlorophenyl group, a dibromophenyl group, a

tetrachlorophenyl group, a difluorophenyl group, a β-cyanoethyl group, a γ-cyanopropyl group, and a β-cyanopropyl group, in which a part of or the entire of hydrogen atoms in a

hydrocarbon group is substituted with a halogen atom, a cyano group, or the like. Particularly preferable organic groups are a methyl group, a -CH₂-CH₂-CH₂-NH-CH₂-CH₂-NH₂ group, and a phenyl grou .

[0017]

The chemical structure, molecular weight, and properties of the organopolysiloxane of the component (A) are not particularly limited, as long as the organopolysiloxane is a resin which satisfies the above-described conditions. Also, the resin may contain, as a main structural unit, a T unit (Si0_3/2) , a Q unit (Si0₂) , or a mixture thereof. Also, the resin may contain an M unit (SiOi/₂) . For example, the resin may be constituted by an M unit and a Q unit.

Also, the form of the resin may be any of liquid, solid, flake-like, powder, and the like.

Also, the component (A) may contain one component, or may be a mixture of two or more components.

[0018]

It is preferable that the component (A) be fluidized after the whole component (A) has been homogenized. When the component (A) mainly contains a solid resin and the like and is difficult to emulsify as it is, the provision of the

fluidity to the component (A) enables emulsification with the silica particle of the component (B) . The method for

homogenization may include, but is not particularly limited to, mixing using a known apparatus.

The degree of fluidity is preferably, but is not

particularly limited to, such that the viscosity after the whole component (A) has been homogenized is low. The upper limit of the viscosity is approximately 100000 mPa-s, depending on the apparatus used. [0019]

When the main component in the component (A) is a

silicone resin having low fluidity, an organopolysiloxane having a viscosity that is lower than that of the resin is preferably contained. Accordingly, fluidization occurs after the whole component (A) has been homogenized. The viscosity at 25°C is preferably 1 to 2000000 mPa-s, more preferably 1 to 100000 mPa-s, and particularly preferably 1 to 50000 mPa-s .

When the viscosity is less than 1 mPa-s or when more than

2000000 mPa'S, emulsification is unlikely to occur, and a stable aqueous dispersion liquid cannot be obtained. The ratio of the low-viscosity organopolysiloxane in the component (A) is not particularly limited. However, when it is excessively high, the ratio of the silicone resin is lowered in end use applications such as cosmetics, possibly causing desired

properties to become insufficient.

The structure of such a component is not particularly limited, as long as it is within the above-described condition. However, dimethylpolysiloxane is preferable from the viewpoint of availability, cost efficiency, and chemical stability.

Examples thereof may include liquid, linear or cyclic

dimethylpolysiloxane .

[0020]

The content of the component (A) in 100 parts by mass of the emulsion is preferably 20 to 80 parts by mass. When the content of the component (A) is less than 20 parts by mass, sufficient emulsification accuracy is not obtained, and the yield decreases . When the content of the component (A) is more than 80 parts by mass, the viscosity of the aqueous emulsion increases, causing a reduction of handling properties. The content of the component (A) is more preferably 30 to 70 parts by mass.

[0021]

The silica particle of the component (B) is a particle of silicon dioxide manufactured by a synthesis method, and does not include mineral-based silica such as diatomaceous earth and crystal quartz. Examples of the silicon dioxide

manufactured by a synthesis method may include fine particles obtained by a dry process, such as fumed silica, pyrogenic silica, and fused silica, and precipitated silica or colloidal silica obtained by a wet process. These are well known to those skilled in the art. Among these, pyrogenic silica, precipitated silica, or colloidal silica is preferably used. The silica particle of the component (B) according to the present invention may be hydrophilic silica on which a silanol group remains, or hydrophobic silica obtained by silylating a silanol group on the surface. The hydrophobic silica can be manufactured by a known method in which the hydrophilic silica is treated with halogenated organic silicon such as

methyltrichlorosilane , alkoxysilanes such as dimethyldialkoxysilane , silazane, and low-molecular weight methylpolysiloxane .

[0022]

When a silica having on its surface both a hydrophobized portion and a silanol group is used as the silica particle of the component (B) , the surface tension of the silica particle is set within the range that is necessary for surface activity Accordingly, the silica particle can be disposed and

stabilized at the interface between an oil phase of an oil droplet and an aqueous phase even in the absence of generally used surfactants.

The ratio of silanol remained after silylation relative to a silanol group before the silylation is preferably 50 to 95%. When the residual rate of silanol is less than 50% or more than 95%, the effect which a surfactant has at the

interface between the oil phase and the aqueous phase cannot be exerted. The ratio of silylation or the residual rate of silanol can be determined by measuring the carbon content through elemental analysis or by measuring the amount of a remained reactive silanol group on the surface of silica. The silica particles used for preparation may include a particle of which the entire surface is silylated or a particle of which the entire surface is not silylated. However, such a silica particle can be used when the silylation ratio as a whole falls within the above-described range, and the necessary emulsification effect can be exerted.

[0023]

The carbon content of the silica particle having both a hydrophobized portion and a silanol group, which is suitably used as the component (B) , is not particularly limited, as long as the object of functioning as a surfactant is

accomplished. However, the carbon content is preferably 0.1 to 10%. When the carbon content is less than 0.1% or more than 10%, a stable emulsion cannot be obtained.

[0024]

The silica particle of the component (B) needs to be powdery, rather than massive. Also, the silica particle may be in the state of a primary aggregate in which primary particles are aggregated, or may be in the state of a secondary

aggregate in which primary aggregates are further aggregated. The particle size is preferably, but is not particularly limited to, roughly within the following range. The particle size of primary particles is approximately within the range of 1 to 100 nm, the particle size of primary aggregates is approximately 50 nm to 1 μτη, and the particle size of secondary aggregates is approximately 1 to 100 μτη.

When the particle size is excessively small, industrial availability is low. When it is excessively large, the silica particle alone is likely to settle down.

[0025] The content of the component (B) in 100 parts by mass of the emulsion is preferably 0.3 to 10 parts by mass. When the content of the component (B) is less than 0.3 parts by mass, the stability of the aqueous dispersion liquid is reduced.

When the content of the component (B) is more than 10 parts by mass, the coating on the emulsion particle becomes excessive, causing occurrence of an unfavorable phenomenon such as

coarseness in the cosmetic applications. The content of the component (B) is more preferably 1 to 7 parts by mass.

[0026]

The producing method of the emulsion composition

according to the present invention is not particularly limited, as long as it does not depart from the scope of the above- described method. The emulsion composition can be manufactured by any known method. For example, the emulsion can be produced by mixing and emulsifying the above-described components using a common mixer suitable for the preparation of an emulsion, such as a homogenizer, a colloid mill, a homomixer, and a high-speed stator rotor stirrer. In order to more

advantageously control the shape and properties of the

particle in more industrially stable manner, there is

recommended a method of obtaining an oil-in-water type

emulsion composition by dispersing 20 to 80 parts by mass of the organopolysiloxane of the component (A) and 0.3 to 10 parts by mass of the silica particle of the component (B) in the water of the component (C) .

[0027]

The producing method of the emulsion composition

according to the present invention more preferably include homogenizing the whole component (A) with an

organopolysiloxane having a viscosity at 25°C of 1 to 2000000 raPa'S for fluidization, and thereafter dispersing the component (A) in water with the silica particle of the component (B) . Accordingly, even when the component (A) is difficult to emulsify, like a solid resin or an elastomer as a main body, emulsification is enabled by bringing the component (A) into contact with the organopolysiloxane so that the whole is fluidized. Therefore, even a resin, which has been difficult to emulsify, can exist in the state of an emulsion. Thus, the problem can be effectively solved.

A more preferable producing method may include adding a powder solid of the component (A) fluidized with the

polyorganosiloxane or the like to an aqueous dispersion liquid of the silica particle of the component (B) , and performing mechanical shearing to obtain the emulsion. In this case, the dispersion process of the silica particle of the component (B) and the water of the component (C) may be performed either before or after the fluidization process of the powder solid of the component (A) with the organopolysiloxane or the like, as long as the power solid of the component (A) dissolved with the organopolysiloxane or the like can be poured into the dispersion liquid of the silica particle of the component (B) and the water of the component (C) .

[0028]

The composition according to the present invention can contain polyoxyalkylene alkyl ethers such as polyoxyethylene tridecyl ether, polyoxyethylene hexadecyl ether, and

polyoxyethylene octadecyl ether, nonionic surfactants such as polyoxyethylene hydrogenated castor oil and polyoxyethylene sorbitan acid ester, and ionic surfactants which are less irritating to the skin, such as sodium lauroyl glutamate and sodium dilauramidoglutamide lysine, within the range that does not impair the object of the present invention.

The amount of the surfactant in 100 parts by mass of the emulsion is preferably 0.1 parts by mass or less, and more preferably 0.06 parts by mass or less. When the amount is more than 1 part by mass, the environment is adversely affected, and the cohesion of the silica particle decreases. Accordingly, the preservation stability of a product and the handleability during dilution are impaired.

[0029]

The silicone emulsion composition according to the

present invention may contain, as a preservative, salicylic acid, sodium benzoate, sodium dehydroacetate , potassium

sorbate, phenoxy ethanol, methyl parahydroxybenzoate, and butyl parahydroxybenzoate, within the range that does not impair the object of the present invention.

[0030]

The silicone emulsion composition according to the

present invention is not particularly limited to contain

particular water, but may preferably contain ion exchanged water. The pH of the ion exchanged water is preferably 2 to 12, and more preferably 4 to 10.

[0031]

The particle size of the organopolysiloxane emulsion composition according to the present invention is, but is not particularly limited to, preferably 100 μπι or less. When the particle size is more than 100 μτη, the size of the particle is excessively large, and the stability of the emulsion particle is impaired. It is noted that in the present invention, the average particle size can be measured using an N4 Plus

particle size distribution measuring device manufactured by Beckman Coulter Inc.

[0032]

Thus, in the silicone resin emulsion composition

according to the present invention, the particle size can be stably controlled with the organopoly iloxane and the silica particle and by the manufacturing method thereof, and the variations in particle size can be narrowed. Accordingly, the preservation stability and the stability during the development of use applications are enhanced. Also, even when the resin is isolated, there is a possibility that high properties derived from the shape of the emulsion particle and the like may be obtained.

[0033]

The silicone resin emulsion composition according to the present invention can be applied onto the surface of a

transparent or opaque base material such as metal, ceramic inorganic materials, concrete, mortar, glass, wood, paper products, plastics, and rubber, and cured at room temperature or by heating and the like to form a cured protective film. This cured protective film has high hardness and excellent flexibility, is favorable in terms of water repellency, heat resistance, weather resistance, scratch resistance, and soil resistance, and possesses adhesiveness.

[0034]

Furthermore, the silicone resin emulsion composition according to the present invention can be used as a water- repellent polish used on the coating surfaces of the sheaths of automobiles, trains, airplanes, vessels, and the like' and as a water-repellent stain prevention agent used on floors, carpets, and the like.

[0035]

Furthermore, in the silicone resin emulsion composition according to the present invention, the isolated resin having the shape of powder or the like can be added to plastics or the like, thereby to be also used as a material for modifying plastics, for example, improving impact resistance or heat resistance .

The isolation method of the resin may include a spray dry method or the like.

[0036]

Furthermore, the silicone resin emulsion composition according to the present invention can be applied to cosmetics such as a hair setting agent, mascara, and a skin care product to be directly brought into contact with the skin. In

particular, the silicone resin emulsion composition according to the present invention can be used as a film formation agent in a sun care product and point makeup product which are required to have water proof properties and UV cutting

properties .

[EXAMPLES]

[0037]

Next, the present invention will be described by way of examples. It is noted that the present invention is not limited by these examples. Also, the evaluation methods of storage stability and of the contact angle with water in

Examples and Comparative Examples are as follows.

[0038]

<Evaluation Method of Storage Stability> Into a 50 ml screw tube, 30 g of a prepared oil-in-water type silicone emulsion was poured, and stored at room

temperature or 50°C for one month. After that, the creaming and the presence or absence of sedimentation were checked.

Evaluation criteria:

A: no creaming and no sedimentation observed

B: some degree of creaming and sedimentation observed

C: creaming and sedimentation observed

[0039]

The contact angle was measured using Contact Angle meter CA-X150 manufactured by FACE Co., Ltd. A drop (approximately 0.002 cc) of ion exchanged water was dropped on the surface of a clean coating film using a microsyringe . After one minute had elapsed, the contact angle was measured. The average value from five measurements was adopted as the contact angle.

[0040]

An oil-in-water type silicone emulsion 1 was prepared as follows. As the silica particle, dry silica which is an aggregate having a BET surface area of 200 mm²/g, a carbon content of 10%, and a particle size of approximately 100 to 1000 nm was used. This dry silica is referred to as a "silica particle 1" below. First, 4.8 parts by mass of the silica particle 1 was stirred in 50 parts by mass of water at 4000 rpm using Ultra-Turrax T50 Basic Shaft Generator G45M manufactured by IKA for dispersion. Thus, an aqueous

dispersion liquid of silica particles was prepared. Next, in another container, 22.6 parts by mass of a flake-like silicone resin were mixed to 22.6 parts by mass of dimethylpolysiloxane of which both terminals are blocked with trimethylsilyl groups and of which the viscosity is 10 mPa-s (25°C) . The mixture was stirred for dissolution to obtain a mixed oil. Next, the prepared mixed oil was added to the aqueous dispersion liquid of the silica particle 1 under the stirring condition of 4000 rpm. Thus, the oil-in-water type silicone emulsion 1 was obtained .

The oil-in-water type silicone emulsion 1 was evaluated for the storage stability and the water repellency of a film. As the evaluation for the water repellency of a film, the contact angle with water was measured. The emulsion

formulation and the evaluation result are indicated in Table 1.

[0041]

An oil-in-water type silicone emulsion 2 was prepared as follows. The oil-in-water type silicone emulsion 2 was

obtained by the same method as that in Example 1, except that 45.2 parts by mass of a silicone elastomer gel having a

viscosity of 100,000 mPa-s (25°C) were used as the component (A). The formulation is shown in Table 1. The oil-in-water type silicone emulsion 2 was evaluated for the storage

stability and the contact angle as the repellency of the film. The results are shown in Table 1.

[0042]

An oil-in-water type silicone emulsion 3 was prepared as follows. First, 22.6 parts by mass of a flake-like silicone resin were mixed to 22.6 parts by mass of dimethylpolysiloxane of which both terminals are blocked with trimethylsilyl groups and of which the viscosity is 10 mPa-s (25°C) . The mixture was stirred for dissolution to obtain a mixed oil. Furthermore, the mixed oil was stirred at 4000 rpm with 10 parts by mass of polyoxyethylene isotridecyl ether (EO 10 mol) and 44.8 parts by mass of water using Ultra-Turrax T50 Basic Shaft Generator G45M manufactured by IKA for dispersion. Thus, the oil-in- water type silicone emulsion 3 was prepared. The formulation is shown in Table 1. The oil-in-water type silicone emulsion 3 was evaluated for the storage stability and the water

repellency of a film. As the evaluation for the water

repellency of a film, the contact angle with water was

measured. The emulsion formulation and the evaluation results are shown in Table 1.

[0043]

An oil-in-water type silicone emulsion 4 was prepared as follows. The oil-in-water type silicone emulsion 4 was obtained by the same method as that in Comparative Example 1, except that 45.2 parts by mass of a silicone elastomer gel having a viscosity of 100,000 mPa^s (25°C) were used as the component (A) . The formulation is shown in Table 1.

The oil-in-water type silicone emulsion 4 was evaluated for the storage stability and the contact angle as the

repellency of the film. The results are shown in Table 1.

[0044]

Preparation of an oil-in-water type silicone emulsion 5 was attempted as follows. First, 5 parts by mass of the silica particle 1 were stirred in 50 parts by mass of water at 4000 rpm using Ultra-Turrax T50 Basic Shaft Generator G45M

manufactured by IKA for dispersion. Thus, an aqueous

dispersion liquid of silica particles was prepared. Next, to the aqueous dispersion liquid of silica particles, 45.2 parts by mass of a flake- like silicone resin were added under the stirring condition of 4000 rpm. An emulsion was not obtained.

[0045] [Table 1]

[0046]

As apparent from the comparisons between Example 1 and Comparative Example 1 and between Example 2 and Comparative Example 2 in Table 1, when a silicone resin or an elastomer gel was used as the component (A) , emulsion preservation stability was ensured by the presence of the silica particle of the component (B) . Also, as apparent from the comparison between Example 1 and Comparative Example 3 in Table 1, the formation of an emulsion was ensured by mixing and stirring low-viscosity dimethylpolysiloxane to the component (A) .

INDUSTRIAL APPLICABILITY

[0047]

The emulsion composition according to the present invention can eliminate the use of an organic surfactant or reduce its amount. Therefore, environmental problems

associated with an organic surfactant can be solved, and stable manufacture can be achieved. Also, the emulsion composition can exist in the form of a stable emulsion.

Furthermore, the properties in terms of use applications can be improved. Therefore, the emulsion composition can be widely applied to coating materials and others which contain a silicone resin. In addition, since an organic surfactant is not contained, the emulsion composition according to the present invention is useful as cosmetic materials to be directly applied on the skin, from the viewpoint of low irritation. Accordingly, there is a possibility that the emulsion composition may be advantageously used in various industries .

Claims

1. An emulsion composition comprising:

(A) 20 to 80 parts by mass of an organopolysiloxane having an average composition represented by general formula (1) ,

[wherein R¹s may be the same as or different from each other in a molecule, and are each a substituted or unsubstituted, saturated or unsaturated monovalent hydrocarbon group having 1 to 25 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom, and a is 0.3 or more and less than 2.0] ;

(B) 0.3 to 10 parts by mass of a silica particle having on a surface thereof a hydrophobized portion and a silanol grou ; and

(C) water, wherein

the silica particle (B) is disposed at an interface between an oil phase of an oil droplet formed from the

organopolysiloxane (A) and an aqueous phase formed from the water (C) .

2. The emulsion composition according to claim 1, wherein the organopolysiloxane (A) is fluidized after the whole organopolysiloxane (A) has been homogenized.

3. The emulsion composition according to claim 1 or 2 , wherein a residual rate of a silanol group after the silanol group on the surface of the silica particle (B) has been silylated is in a range of 50 to 95 mol%.

4. A method for producing an emulsion composition, the emulsion composition comprising

(A) 20 to 80 parts by mass of an organopolysiloxane having an average composition represented by general formula (1),

[wherein R¹s may be the same as or different from each other in a molecule, and are each a substituted or unsubstituted, saturated or unsaturated monovalent hydrocarbon group having 1 to 25 carbon atoms, a substituted or unsubstituted aromatic group having 6 to 30 carbon atoms, a hydroxy1 group, an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom, and a is 0.3 or more and less than 2.0] ,

(B) 0.3 to 10 parts by mass of a silica particle having on a surface thereof a hydrophobized portion and a silanol group, and

(C) water, wherein

organopolysiloxane (A) and an aqueous phase formed from the water (C) , the method comprising:

dispersing the silica particle (B) in the water (C) in advance to form a dispersion liquid;

adding the organopolysiloxane (A) entirely having been fluidized to the dispersion liquid of the silica particle (B) in the water (C) ; and

dispersing the organopolysiloxane (A) in the dispersion liquid .

5. A coating composition comprising the emulsion composition according to any one of claims 1 to 3.

6. A composition for cosmetics comprising the emulsion composition according to any one of claims 1 to 3.