JPH10265577A - Method for producing polyorganosiloxane microemulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyorganosiloxane microemulsion of 0.15 micron or less having a wide concentration range and a good stability without requiring a special emulsifier, by a simple operation. And a method for producing a polyorganosiloxane microemulsion. (A) (a) a nonionic surfactant,
(B) a step of mixing an anionic surfactant and (c) water to obtain a uniform surfactant aqueous solution, and (B) a specific organosiloxane is sequentially added to the aqueous solution obtained in the above step to form an emulsion. The step of obtaining, (C) the step of heating and cooling and stirring the obtained emulsion to carry out emulsion polymerization is carried out to produce a polyorganosiloxane microemulsion having an average particle size of 0.15 μm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyorganosiloxane microemulsion capable of producing a stable polyorganosiloxane microemulsion having an average particle diameter of 0.15 μm or less by a simple operation.

[0002]

BACKGROUND OF THE INVENTION Conventionally, as a method for producing an aqueous emulsion of a polyorganosiloxane, a mechanical emulsification method and an emulsion polymerization method are known. Here, the mechanical emulsification method comprises a step of applying mechanical energy to a mixture of a polyorganosiloxane, a surfactant and water to uniformly emulsify and disperse. However, in the case of this mechanical emulsification method, the polyorganosiloxane oil has a low surface tension and a high hydrophobicity, so that it is difficult to emulsify and disperse. It is necessary to perform emulsification by a dispersing device such as a colloid mill during the phase inversion from / O to O / W. For example,
In U.S. Pat. No. 2,755,194, surfactants are used.
A method of mixing a polydimethylsiloxane having a viscosity of 350 cS, adding a small amount of water to the mixture, emulsifying and dispersing in a colloid mill, and then continuously adding water to obtain a desired emulsion is shown. ing. However, in the mechanical emulsification method, only a polyorganosiloxane within the range of the physical energy of the equipment used can be used, and generally only a polyorganosiloxane having a viscosity up to about 500,000 cS can be emulsified (Japanese Patent Application Laid-Open No. 63-125530).
No., JP-A-56-109227). Furthermore, due to the structure of the dispersing device, the size of the obtained emulsion particles was at most 0.3 μm, and it was difficult to produce an emulsion of 0.3 μm or less. It should be noted that U.S. Pat.
No. 052331 proposes a method for producing a transparent emulsion having a small average particle diameter by a mechanical emulsification method. However, in this method, a special surfactant is used, and the amount of the surfactant used is large relative to the polyorganosiloxane. Therefore, the siloxane concentration in the emulsion is low, and the polyorganosiloxane used is also low. There is a disadvantage that it is limited to those having a low molecular weight. Furthermore, in the mechanical emulsification method, a method of dissolving a high-viscosity fluid or resin in an organic solvent and emulsifying and dispersing the same is also known (JP-B-63-45748, JP-A-60-1258, JP-A-60-125
No. 9). However, since this method uses a flammable organic solvent, it is not a desirable method in terms of environmental health and safety.

[0003] On the other hand, the emulsion polymerization method involves emulsifying and dispersing a mixture of a low-molecular-weight siloxane or a reactive siloxane oligomer as a siloxane monomer, a surfactant, a water-soluble polymerization catalyst and water, and stirring and mixing until the reaction is completed. In the method for obtaining a polymer emulsion of the above, an emulsion of an organopolysiloxane having a wide viscosity range from a low molecular weight oil to a high molecular weight raw rubber region can be produced. As the emulsion polymerization method, for example, a method of emulsifying and dispersing a low-molecular-weight siloxane and then adding a strong acid or a strong alkali catalyst to carry out emulsion polymerization (see Japanese Patent Publication No. 34-2041), a method of converting a low-molecular-weight siloxane into an interface having catalytic activity. Simultaneous emulsification, dispersion and polymerization using an activator
No. 3-18800), a method in which an organosiloxane is emulsified in an aqueous solution of a salt type anionic surfactant, and then the emulsion is contacted with an acetic acid cation exchange resin to carry out polymerization (Japanese Patent Publication No. 54-19440). ), A method of polymerizing siloxanes and silcarbanes in an emulsified and dispersed state in the presence of a specific surface active sulfonic acid catalyst (JP-B-41-1399, JP-B-44-201).
No. 16). However,
Emulsions obtained by these methods are generally milky, opaque and have an average particle size of greater than 0.3 microns, are transparent or translucent, have high light transmittance, and are expected to have high utility values of 0.15 microns or less. It was difficult to obtain a microemulsion having an average particle size of
Therefore, as a method for producing a siloxane microemulsion having a smaller average particle size, a precursor emulsion composed of cyclosiloxane, a surfactant, and water is added to a mixture of water and a polymerization catalyst while mixing, and the average particle size is reduced to 0. .
A method for producing a transparent polyorganosiloxane microemulsion having a size of 15 μm or less has been proposed (see JP-A-62-141029). However, in this method, the precursor emulsion has to be produced in advance, so that the production process is complicated in two steps, and the polysiloxane concentration in the precursor emulsion is limited. There was a problem that the concentration was also limited. Furthermore, as a method for producing a silicone microemulsion having a small average particle diameter, a low molecular weight organopolysiloxane is emulsified and dispersed in water in the presence of a surfactant to obtain an initial emulsion, and then high-pressure shear energy is continuously applied. A method for producing an organopolysiloxane microemulsion by emulsion polymerization (see Japanese Patent Publication No. 6-15612) and a method for applying ultrasonic energy instead of high-pressure shear energy (see Japanese Patent Publication No. 6-15613) are proposed. Have been.

[0004] However, these methods rely on the energy of an emulsifying apparatus, and have a disadvantage that an apparatus for applying such high-pressure shear energy or ultrasonic energy is required. Furthermore, methods for producing standard emulsions and microemulsions by reacting cyclic siloxanes with stirring in the presence of a nonionic surfactant, an ionic (cationic or anionic) surfactant, water and a catalyst have been proposed. However, when a microemulsion is to be obtained by this method, particularly when an anionic surfactant is used, the average particle size cannot be sufficiently controlled, and furthermore, dodecylbenzene sulfone When an emulsifier other than an acid is used, there is a problem that a creaming phenomenon occurs. In addition, although a method for producing an amino-functional silicone microemulsion has been proposed (see Japanese Patent Application Laid-Open No. H5-209958), there is a disadvantage that the method is limited to those based on amino-functional silicone.

[0005]

The object of the present invention is to provide a polyorganosiloxane microemulsion of 0.15 micron or less which has a wide concentration range and a good stability without requiring a special emulsifier. An object of the present invention is to provide a method for producing a polyorganosiloxane microemulsion, which can be obtained by a simple operation.

[0006]

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that an aqueous solution of a specific surfactant
The present inventors have found that a microemulsion having good stability can be obtained by successively adding organosiloxane at a constant rate and conducting emulsion polymerization, thereby completing the present invention. That is, the present invention provides (A) (a) a nonionic surfactant, (b) an anionic surfactant, (c) a step of mixing water to obtain a uniform aqueous surfactant solution, and (B) a step of obtaining a uniform surfactant aqueous solution. In the obtained aqueous solution, general formula (I) R ¹ _n SiO _{(4-n) / 2} ... (I) (wherein, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, and n is 0 to 0) An integer of 3). An average comprising: a step of successively adding an organosiloxane having a structural unit represented by the following formula to obtain an emulsion; and (C) a step of heating and cooling and stirring the obtained emulsion to carry out emulsion polymerization. Particle size
This is a method for producing a polyorganosiloxane microemulsion of 0.15 microns or less.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention will be described below in detail. The organosiloxane used in the present invention is:
Formula (I) R ¹ _n SiO _{(4-n) / 2} (I) (wherein, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, and n represents an integer of 0 to 3) Is a low molecular weight organosiloxane having a structural unit represented by the formula:
Although it has a branched or cyclic structure, it is preferably an organosiloxane having a cyclic structure. Examples of the substituted or unsubstituted monovalent hydrocarbon group possessed by the low molecular weight organosiloxane include a methyl group, an ethyl group, a propyl group, a vinyl group, a phenyl group and a substituted group obtained by substituting the same with a halogen atom or a cyano group. Examples include a hydrocarbon group. Specific examples of the organosiloxane include cyclic compounds such as hexamethyltrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and trimethyltriphenylcyclotrisiloxane; Organosiloxanes. The organosiloxane was previously condensed, for example, having a polymerization average molecular weight of 1
It may be about 62 to 10,000 polyorganosiloxane. Further, when the organosiloxane is a linear or branched organosiloxane, the molecular chain terminal thereof,
For example, it may be blocked with a hydroxyl group, an alkoxy group, a trimethylsilyl group, a dimethylvinylsilyl group, a methylphenylvinylsilyl group, a methyldiphenylsilyl group, or the like. Examples of such organosiloxanes include hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, hexadecamethylheptasiloxane, hexaethyldisiloxane, tetramethyldiethyldisiloxane, tetramethyldivinyldisiloxane, and tetramethyldihydroxydisiloxane. And octamethyldihydroxytetrasiloxane.
In the present invention, as the low molecular weight organosiloxane, it is preferable to use a mixture of the above-described cyclic organosiloxane as a main component and a chain organosiloxane serving as a terminal stopper, and by using this mixture, emulsification is achieved. The number of siloxane units of the polyorganosiloxane after polymerization can be controlled arbitrarily.

[0008] In this case, the mixing ratio of the two organosiloxanes is not particularly limited.
It is preferable to mix the chain organosiloxane in a proportion of 60 to 0.01 mol%, especially 30 to 0.1 mol%, and the polyorganosiloxane is mixed in the proportion described above. The molar ratio of the siloxane units therein can be easily adjusted. Further, the amount of the low molecular weight organosiloxane used is not particularly limited, but the concentration of the organosiloxane at the time of emulsion polymerization is 5 to 5.
It is preferred that the content be 60% by weight, especially 10 to 50% by weight. That is, 5% by weight or more is preferable from the viewpoint of emulsification efficiency, handling is good because the increase in the viscosity of the emulsion is small, and 60% by weight or less is preferable because the efficiency of micronization is good.

Next, as the anionic surfactant used in the present invention, aliphatic substituted benzenesulfonic acid, aliphatic substituted naphthalenesulfonic acid, aliphatic substituted sulfonic acid,
Examples thereof include silylalkyl sulfonic acid, aliphatic substituted diphenyl ether sulfonic acid, alkyl sulfate, polyoxyalkylene alkyl ether sulfate, polyoxyalkylene alkyl ether carboxylate, and salts thereof. Among these, emulsification is performed well, and not only the action as an emulsifier,
Since it also works well as a catalyst for emulsion polymerization, it is represented by the following general formulas (II) to (V): aliphatic substituted benzenesulfonic acid, aliphatic hydrogen sulfate, unsaturated aliphatic sulfonic acid, and hydroxylated fatty acid. Aromatic sulfonic acids and the like are preferably used. R ² C ₆ H ₄ SO ₃ H… (II) R ² OSO ₂ H… (III) R ³ CH = CH (CH ₂ ) _l SO ₃ H… (IV) R ³ CH ₂ CH (OH) (CH ₂ ) _m SO ₃ H (V) (wherein, R ² is a monovalent aliphatic hydrocarbon group having 6 to 30 carbon atoms, and R ³ is a monovalent aliphatic hydrocarbon group having 1 to 30 carbon atoms) ,
L and m are integers such that the total number of carbon atoms in the surfactants of the formulas (IV) and (V) is 6 to 30. Here, R ² is a monovalent aliphatic hydrocarbon having 6 to 30, preferably 6 to 18 carbon atoms, such as hexyl, octyl, decyl, dodecyl, cetyl, stearyl,
Examples include a myrisyl group, an oleyl group, a nonenyl group, an octyl group, a phytyl group, and a pentadecadienyl group. R ³ is a monovalent aliphatic hydrocarbon group having 1 to 30, preferably 6 to 18 carbon atoms, and examples thereof are the same as those of R ² .

Examples of the aliphatic substituted benzenesulfonic acid represented by the formula (II) include hexylbenzenesulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, and cetylbenzenesulfonic acid, and are represented by the formula (III). Examples of the aliphatic hydrogen sulfate include octyl sulfate, lauryl sulfate, oleyl sulfate, and cetyl sulfate, and examples of the unsaturated aliphatic sulfonic acid represented by the formula (IV) include tetradecene sulfonic acid, and (V) Examples of the hydroxylated aliphatic sulfonic acid represented by the formula include hydroxytetradecanesulfonic acid. The unsaturated aliphatic sulfonic acid and the hydroxylated aliphatic sulfonic acid are preferably used in combination because the resulting emulsion is less likely to be colored over time.

Further, an anionic surfactant having a weak catalytic action is preferably used in combination with a polymerization catalyst. Examples of such anionic surfactants having a weak catalytic action include aliphatic substituted benzenesulfonic acids of the above general formulas (II) to (V), aliphatic hydrogen sulfates, unsaturated aliphatic sulfonic acids and hydroxylated aliphatic. Sodium salts such as sulfonic acid, potassium salts, and salts such as ammonium salts are exemplified.Specifically, sodium dodecylbenzenesulfonate, sodium octylbenzenesulfonate, ammonium dodecylbenzenesulfonate, sodium lauryl sulfate, ammonium lauryl sulfate,
Examples include triethanolamine lauryl sulfate. Other anionic surfactants having weak catalytic action include, for example, polyoxyethylene (4) lauryl ether sulfate, polyoxyethylene (13) cetyl ether sulfate, polyoxyethylene (6) stearyl ether sulfate, polyoxyethylene (4 ) Sodium lauryl sulfate, polyoxyethylene (4) polyoxyethylene alkyl ether sulfate such as ammonium octyl phenyl ether sulfate or a salt thereof, polyoxyethylene (3) lauryl ether carboxylic acid, polyoxyethylene (3) stearyl ether carboxylic acid, Sodium polyoxyethylene (6) lauryl ether carboxylate,
Examples thereof include a polyoxyethylene alkyl ether carboxylate such as sodium polyoxyethylene (6) octyl ether carboxylate or a salt thereof. When an anionic surfactant having a weak catalytic action is used, it is preferable to use it in combination with a catalyst for emulsion polymerization. Examples of such a polymerization catalyst include those generally known as polymerization catalysts for low-molecular-weight siloxane. Can be used, for example hydrochloric acid,
Acidic catalysts such as sulfuric acid and phosphoric acid are exemplified. In addition, an anionic surfactant having a weak catalytic action may be used in combination with an anionic surfactant having a good catalytic action as described above,
Alternatively, the above-mentioned polymerization catalyst may be used in combination with an anionic surfactant having good catalytic action.

The amount of the anionic surfactant to be used is preferably 2 to 100 parts by weight, particularly 5 to 50 parts by weight, based on 100 parts by weight of the above low molecular weight organosiloxane. This is because the amount is preferably 2 parts by weight or more because it has good stability without performing, and less than 100 parts by weight because it has good fluidity without thickening. When a polymerization catalyst is used, the amount used is not particularly limited, but since the polymerization reaction proceeds well and the reaction can be easily controlled, 0.1 to 100 parts by weight of the low molecular weight organosiloxane is used.
Preferably it is 20 parts by weight.

As the nonionic surfactant used in the present invention, those having an HLB of 6 to 20 are preferably used.
For example, 2,6,8-trimethyl-4-nonyloxypolyethylene (6) oxyethanol, 2,6,8-trimethyl-4-nonyloxypolyethylene (10) oxyethanol, polyoxyethylene (7) secondary alcohol ether, poly Oxyethylene (12) secondary alcohol ether, polyoxyethylene (7) tridecyl ether, polyoxyethylene (12) tridecyl ether, polyoxyethylene (6) lauryl ether,
Polyoxyethylene (7) cetyl ether, polyoxyethylene (20) stearyl ether, polyoxyethylene (3) octyl phenyl ether, polyoxyethylene (18) nonyl phenyl ether, polyethylene glycol monostearate (EO 14), distearic acid Polyethylene glycol (EO 80), polyoxyethylene (20) hydrogenated castor oil, polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monopalmitate, polyoxyethylene (6) sorbitan monostearate, trio Polyoxyethylene (20) sorbitan oleate, polyoxyethylene (40) sorbite tetraoleate, polyoxyethylene (15) glyceryl monooleate, polyoxyethylene (15) glyceryl monostearate Sorbitan monopalmitate, polyoxyethylene (10) behenyl ether, polyoxyethylene (10) phytosterol, polyoxyethylene (10) polyoxypropylene (4) cetyl ether, polyoxyethylene (5) stearylamine, polyoxyethylene ( 8) Stearyl propylene diamine, polyoxyethylene (5) sodium cetyl ether phosphate, and the like, but are not limited thereto. In addition, even if the HLB alone is not 6 to 20, the combination of a plurality of nonionic surfactants makes the HLB 6
It should be ~ 20. The amount of nonionic surfactant used is
It is preferable to use 1 to 100 parts by weight, particularly 2 to 70 parts by weight, based on 100 parts by weight of the low molecular weight organosiloxane. The content is preferably 100 parts by weight or less because a microemulsion having a smaller average particle diameter of 0.15 μm or less can be obtained favorably.

The amount of water used in the present invention is usually 50 to 1000 parts by weight, preferably 100 to 500 parts by weight, based on 100 parts by weight of the organosiloxane. The amount is preferably at least 50 parts by weight since an emulsion having good stability can be obtained, and the amount is preferably at most 1,000 parts by weight because the siloxane concentration in the emulsion does not become too low and the obtained emulsion can be developed for a wide range of uses.

In the production of the polyorganosiloxane microemulsion of the present invention, first, the above-mentioned (a) a nonionic surfactant, (b) an anionic surfactant, (c) water, and if necessary, an emulsion polymerization catalyst To prepare a uniform aqueous solution of a surfactant (first step (A)). Next, an emulsion is prepared by sequentially adding low molecular weight organosiloxane to this aqueous solution (second step (B)). In this case, since a microemulsion having a small particle size can be obtained favorably, the aqueous solution is 20 to 80.
C., preferably 30 to 60.degree. C., and the organosiloxane is preferably added sequentially with stirring over 10 minutes to 24 hours, especially 1 hour to 15 hours. The organosiloxane may be added continuously at a substantially constant flow rate so that the entire amount is added in a desired time, and the flow rate may have a difference of about twice between the minimum and the maximum. It is preferable to be within 1.5 times. Or, even if it is not continuous, the organosiloxane is
It can also be added at substantially equal intervals in two or more portions, preferably in five or more portions. The amount of the organosiloxane to be divided may be approximately the same, and the difference may be about twice, but is preferably within 1.5 times. In addition, the interval in the case of dividing and adding may have a difference of about 2 times, but it is preferable to be within 1.5 times. Further, the emulsion thus obtained is subjected to emulsion polymerization while stirring under heating and cooling (third step (C)) to produce the desired polyorganosiloxane microemulsion. Heat stirring and cooling stirring when the emulsion polymerization proceeds, since the emulsion polymerization proceeds favorably, and particles having a uniform and smaller particle size are obtained, heat stirring is performed at 60 to 95 ° C. for 1 to 15 hours. In particular, it is preferable to perform cooling and stirring at 70 to 90 ° C. for 2 to 10 hours, and then perform cooling and stirring at 0 to 40 ° C. for 1 to 500 hours, particularly at 10 to 30 ° C. for 2 to 100 hours. Thereafter, when the polyorganosiloxane reaches a desired degree of polymerization, the polymerization is stopped by adding an alkaline substance to neutralize the polymerization catalyst, thereby obtaining the polyorganosiloxane microemulsion of the present invention. Examples of the alkaline substance in this case include inorganic substances such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, and potassium acetate; ammonia; and amines such as triethanolamine.

In order to further stabilize the polyorganosiloxane microemulsion thus obtained, a nonionic surfactant, glycerin, water-soluble alkylene glycol, water-soluble polyoxyalkylene glycol and the like can be added.

The polyorganosiloxane microemulsion obtained by the production method of the present invention can be used for various cosmetics including hair cosmetics, skin cosmetics, makeup cosmetics, and various polishing agents for automobiles, furniture, leather products and the like. And surface protective agents, surface treatment agents such as weather strips to improve lubricity, textile treatment agents for clothing, curtains, bedding, etc., defoaming agents used in wastewater treatment, food production, etc.
Used for various applications.

[0018]

According to the method for producing a polyorganosiloxane microemulsion of the present invention, no special emulsifier is required, and there is no need to produce a precursor emulsion, and the stability is improved by a simple operation. The average particle size is
A polyorganosiloxane microemulsion of 0.15 microns or less is obtained.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. Example 1 In a flask equipped with a stirrer, 250 g of water, 50 g of dodecylbenzenesulfonic acid, and 10 g of polyoxyethylene (6) lauryl ether were added and mixed, and uniformly dissolved to prepare an aqueous solution of a surfactant. Let warm. 100 g of octamethylcyclotetrasiloxane was added dropwise thereto at a temperature of 40 ° C. over 10 hours while stirring. After dropping, add another 90
The mixture was heated and stirred at 5 ° C for 5 hours, and then stirred at 15 ° C for 10 hours.
Then, the polymerization reaction was terminated by neutralization with triethanolamine to obtain a target polyorganosiloxane microemulsion. The measured average particle size of this emulsion was 0.028 microns. Further, isopropyl alcohol was added to the emulsion to break the emulsion, and the silicone oil was separated and the viscosity was measured. The result was 163,000 cP at 25 ° C. Further, the obtained emulsion was stored at room temperature for one month and its stability was examined. As a result, no oil separation or the like was observed, indicating good stability.

Example 2 In a flask equipped with a stirrer, 250 g of water, 30 g of sodium tetradecenesulfonate, 10 g of sodium hydroxytetradecanesulfonate, 12 g of polyoxyethylene (9) tridecyl ether, and 2 g of sulfuric acid were mixed and uniformly dissolved. An aqueous solution of a surfactant was prepared and heated to 60 ° C. As the sodium tetradecenesulfonate and sodium tetradecanesulfonate, a commercially available product (K Liporan PJ-400, manufactured by Lion Corporation) that can be obtained as a mixture of these was used. A mixture of 150 g of octamethylcyclotetrasiloxane and 0.5 g of hexamethyldisiloxane was added dropwise at 60 ° C. over 3 hours while stirring. After dropping,
The mixture was heated and stirred at 85 ° C for 3 hours, and then stirred at 25 ° C for 5 hours. Then, the polymerization reaction was terminated by neutralization with a 10% aqueous sodium carbonate solution, and 50 g of glycerin was added and mixed as an additive for further improving the stability to obtain a desired polyorganosiloxane microemulsion. The average particle size of this emulsion was measured to be 0.095
Micron. Further, isopropyl alcohol was added to this emulsion to break the emulsion, and the silicone oil was separated and the viscosity was measured.
000cP.

When the obtained emulsion was stored at room temperature for one month and its stability was examined, no separation of oil was observed and good stability was shown.

Example 3 250 g of water, 26.25 g of sodium tetradecenesulfonate, 8.75 g of sodium hydroxytetradecanesulfonate, 5 g of polyoxyethylene (7) secondary alcohol ether, 5 g of sulfuric acid, and 2 g of sulfuric acid were added to a flask equipped with a stirrer. Thus, an aqueous solution of a surfactant was prepared, and the temperature was raised to 85 ° C. A mixture of 100 g of octamethylcyclotetrasiloxane and 3.0 g of methyltrimethoxysilane was added dropwise thereto at a temperature of 85 ° C. over 6 hours while stirring. After completion of the dropwise addition, the mixture was further heated and stirred at 85 ° C for 3 hours, and then stirred at 10 ° C for 5 hours. And ten
The polymerization reaction was terminated by neutralization with an aqueous sodium carbonate solution to obtain the desired polyorganosiloxane microemulsion. The measured average particle size of this emulsion was 0.072 microns. Further, isopropyl alcohol was added to this emulsion to break the emulsion, and the silicone component was separated to obtain a gel. Further, the obtained emulsion was stored at room temperature for one month and its stability was examined. As a result, no oil separation or the like was observed, indicating good stability.

Example 4 Into a flask equipped with a stirrer, 250 g of water, 45 g of dodecylbenzenesulfonic acid, and 10 g of 2,6,8-trimethyl-4-nonyloxy polyethylene (6) oxyethanol were added and mixed, uniformly dissolved and mixed. An aqueous solution of the activator was prepared and heated to 70 ° C. A mixture of 100 g of octamethylcyclotetrasiloxane and 1.0 g of decamethyltetrasiloxane was added dropwise thereto at 70 ° C. with stirring over 2 hours. After the completion of dropping, further at 70 ° C
The mixture was heated and stirred for 15 hours, and then stirred at 15 ° C. for 5 hours. And
The polymerization reaction was terminated by neutralization with a 10% aqueous solution of sodium carbonate to obtain a target polyorganosiloxane microemulsion. The measured average particle size of this emulsion was 0.035 microns. Further, isopropyl alcohol was added to this emulsion to break the emulsion, and the silicone oil was separated and the viscosity was measured. The result was 6,500 cP at 25 ° C. Further, the obtained emulsion was stored at room temperature for one month and its stability was examined. As a result, no oil separation or the like was observed, indicating good stability.

Comparative Example 1 An emulsion was prepared in the same manner as in Example 1 except that octamethylcyclotetrasiloxane was charged together with water and a surfactant, and a polyorganosiloxane microemulsion having an average particle size of 0.070 μm was obtained. Obtained. However, when the obtained emulsion was stored at room temperature for one month and its stability was examined, a phenomenon (creaming phenomenon) in which a cream-like thickened substance was formed in the upper layer of the emulsion was observed.

COMPARATIVE EXAMPLE 2 An emulsion was prepared in the same manner as in Example 2, except that the mixture of octamethylcyclotetrasiloxane and hexamethyldisiloxane was not added dropwise over 3 hours, but was added within 1 minute. However, a creaming phenomenon was observed in the upper layer of the obtained emulsion, and a uniform emulsion could not be obtained. When the average particle size of the emulsion in the lower layer was measured, it was 0.250 μm.

Claims (1)

[Claims] (A) (a) a nonionic surfactant, (b) an anionic surfactant, (c) a step of mixing water to obtain a uniform aqueous surfactant solution, and (B) a step of obtaining a uniform surfactant aqueous solution. In the aqueous solution, R ¹ _n SiO _{(4-n) / 2} ... (I) (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, and n is 0 to 3) An average particle size comprising: a step of sequentially adding an organosiloxane having a structural unit represented by the following formula to obtain an emulsion; and (C) a step of heating and cooling and stirring the obtained emulsion to carry out emulsion polymerization. Diameter
A method for producing a polyorganosiloxane microemulsion of 0.15 microns or less.