JPH0611769B2 - Method for producing dispersion of heat-resistant fine resin particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a dispersion liquid of fine resin particles having excellent heat resistance and solvent resistance, and more specifically to a polymerization containing a maleimide compound. Method of polymerizing a water-soluble monomer in an aqueous medium containing a specific organic solvent to obtain a dispersion of heat-resistant resin fine particles having a particle size of 100 microns or less and a relatively narrow particle size distribution. It is about.

(Problems to be Solved by Conventional Techniques and Inventions) Fine resin particles have been conventionally used as pigments and fillers such as molded products, paints and adhesives. At present, there are problems such as insufficient solvent properties and generation of decomposition gas.

In view of these facts, the present inventors have earnestly studied, as a result, a polymerizable monomer containing a maleimide compound, a particle size by polymerizing in an aqueous medium containing a specific organic solvent The present invention has been completed by finding that a dispersion liquid of fine resin particles having a heat resistance of 100 μm or less and a relatively narrow particle size distribution and being excellent can be easily obtained.

(Means and Effects for Solving Problems) That is, the present invention has the general formula (In the formula, R ₁ and R ₂ are each independently hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group, or a substituted aryl group, R ₃ is hydrogen, an alkyl group having 1 to 15 carbon atoms, A cycloalkyl group, an aryl group or a substituted aryl group.), A polymerizable monomer containing a maleimide compound represented by the formula (1), an organic solvent capable of dissolving the polymerizable monomer and miscible with water. The present invention relates to a method for producing a dispersion liquid of heat-resistant fine resin particles, which is characterized by being polymerized in an aqueous medium.

The maleimide compound used in the present invention is represented by the above general formula, for example, maleimide, N-
Methyl maleimide, N-ethyl maleimide, N-propyl maleimide, N-isopropyl maleimide, N-butyl maleimide, N-isobutyl maleimide, N-tertiary butyl maleimide, N-cyclohexyl maleimide, N-lauryl maleimide, N-phenyl maleimide, N- (2-chlorophenyl) maleimide, N- (3
-Chlorophenyl) maleimide, N- (4-chlorophenyl) maleimide, N- (4-bromophenyl) maleimide, N- (2,4,6-trichlorophenyl) maleimide, N- (2,4,6-tri) Bromophenyl) maleimide, N- (2-methylphenyl) maleimide, N-
(3-Methylphenyl) maleimide, N- (4-methylphenyl) maleimide, N- (2-tert-butylphenyl) maleimide, N- (3-tertiarybutylphenyl) maleimide, N- (4-tertiarybutyl) Phenyl) maleimide, N- (2,6-dimethylphenyl) maleimide, N- (2-nitrophenyl) maleimide, N
-(3-Nitrophenyl) maleimide, N- (4-nitrophenyl) maleimide, N- (2,4-dinitrophenyl) maleimide, N- (2-hydroxyphenyl) maleimide, N- (3-hydroxyphenyl) maleimide , N- (4-hydroxyphenyl) maleimide, N-
(2-Methoxyphenyl) maleimide, N- (3-methoxyphenyl) maleimide, N- (4-methoxyphenyl) maleimide, N- (4-ethoxyphenyl) maleimide, N- (2-methoxy-4-chlorophenyl) Maleimide, N- (4-phenylphenyl) maleimide, N
-(4-phenyloxyphenyl) maleimide, N- (4
-Benzylphenyl) maleimide, N- (4-benzyloxyphenyl) maleimide, N- (4-phenoxymethylphenyl) maleimide, N- (2-chloro-4-phenoxyphenyl) maleimide, N-naphthylmaleimide, N- ( 2-carboxyphenyl) maleimide, N-
(4-Carboxyphenyl) maleimide, α-chloro-
Examples thereof include N-phenylmaleimide and α-methyl-N-phenylmaleimide, and of these, one kind or two or more kinds can be used.

The polymerizable monomer used in the present invention comprises the above-mentioned maleimide compound, and in consideration of the required heat resistance and solvent resistance, the heat resistance of the obtained fine resin particles and the solvent resistance are impaired. Other monomers that can be copolymerized with the maleimide compound can be used in combination as long as the amount does not exist. Preferably, another monomer is used in combination in such a proportion that the maleimide compound is the main component of the polymerizable monomer. When the amount of the other monomer used exceeds the ratio of the maleimide compound as the main component of the polymerizable monomer, the heat resistance of the resulting resin particles may be insufficient in some cases, or the solvent resistance There is a case where the sex is deteriorated.

As these other monomers, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, C1-C18 alkyl groups such as octyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, 3-phenylpropyl methacrylate, etc. Methacrylic acid esters having; methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, Acrylic esters having an alkyl group having 1 to 18 carbon atoms, such as amyl acrylate, isoamyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, cyclohexyl acrylate, and benzyl acrylate; Vinyl aromatics such as styrene, α-methylstyrene, paramethylstyrene, vinyltoluene, isopropenylstyrene and chlorostyrene; unsaturated nitriles such as acrylonitrile, methacrylonitrile, ethacrylotolyl and phenylacrylonitrile; ethylene glycol diacrylate or methacrylate. , Hexanediol diacrylate or methacrylate, divinylbenzene, trimethylolpropane triacrylate or methacrylate,
Pentaerythritol tetraacrylate or methacrylate, dipentaerythritol hexaacrylate or methacrylate, diacrylate or methacrylate of ethylene oxide or propylene oxide adduct of bisphenol A, diacrylate or methacrylate of ethylene oxide or propylene oxide adduct of halogenated bisphenol A, isocyanate Polyacrylates or methacrylates such as triacrylate or methacrylate of nurate, ethylene oxide or propylene oxide adduct of isocyanurate such as di- or triacrylate or methacrylate; triallyl isocyanurate, polyarylates such as diallyl phthalate; Glycidyl acrylate or methacrylate, allyl glycy Functional monomers such as ether, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid or their half-esterified products, and the like, and one or more of these may be used depending on the purpose. However, these types and amounts used may be selected within the range not departing from the object of the present invention.

The resin particles contained in the dispersion liquid of the heat-resistant fine resin particles obtained by the method of the present invention are spherical fine particles having a size of 0.01 to 100 μm. The dispersion liquid of the fine particles can be easily prepared by emulsion polymerization or suspension polymerization of the polymerizable monomer. The polymerization reaction is carried out under autogenous pressure or under pressure in an inert gas atmosphere at a temperature of 0 ° C or lower to 100 ° C.
It is carried out at temperatures of ° C or higher.

The polymerization initiator used in the polymerization is a conventionally known free radical polymerization initiator such as benzoyl peroxide, lauryl peroxide, hydrogen peroxide, potassium persulfate, or an oil-soluble or water-soluble peroxide such as ammonium persulfate. Azo compounds such as azobisisobutyronitrile are suitable. It is also possible to effectively proceed with the polymerization reaction by jointly using a reducing agent such as dimethylaniline, sodium hydrogen sulfite, ascorbic acid and ferrous sulfate.

In the present invention, the polymerization of the polymerizable monomer is carried out in an aqueous medium containing an organic solvent capable of dissolving the polymerizable monomer and miscible with water. At the initial stage of the polymerization, the polymerizable monomer and the prepolymer are dissolved or finely dispersed in the aqueous medium, and as the polymerization progresses, a fine-particle polymer having a high molecular weight is produced in the aqueous medium. However, the particulate polymer produced during the polymerization does not fuse and become coarse. The organic solvent is amphipathic to water and the polymerizable monomer, and aids the dissolution or fine dispersion of the polymerizable monomer and the initial polymer at the initial stage of polymerization to form a fine particle polymer. After that, it contributes to the stability of the produced particles in the aqueous medium.

In the present invention, in order to start the polymerization in an aqueous medium, for example, the polymerizable monomer is added to the aqueous medium containing the organic solvent and well mixed to dissolve or finely disperse the polymerizable monomer. After that, it may be a method of initiating the polymerization, or in a water medium or an aqueous medium containing the organic solvent, after adding a solution of a polymerizable monomer dissolved in the organic solvent all at once, start the polymerization Although it may be a method, in order to further increase the stability of the produced polymer particles and obtain heat-resistant fine resin particles having a narrow particle size distribution, the organic solvent of the polymerizable monomer in an aqueous medium or the aqueous medium is used. A method of adding the solution all at once and then initiating the polymerization is preferable.

The organic solvent used in the present invention is not particularly limited as long as it can dissolve the polymerizable monomer and is miscible with water, and examples thereof include methanol, ethanol, propanol, isopropanol, t-butanol and methyl cellosolve. , Ethyl cellosolve, butyl cellosolve, cellosolve acetate, methyl cellosolve acetate, diethyl carbitol, methyl carbitol, carbitol acetate, dioxane, tetrahydrofuran, dimethylformamide, dimethylformoxide, methyl ethyl ketone, acetone, methyl acetate, ethyl acetate, ethylene glycol, diethylene glycol And the like, and one or more of these are used.

In the present invention, the polymerization is carried out in an aqueous medium containing the above-mentioned specific organic solvent, but in some cases, a small amount of a known emulsifying agent or suspending agent may be used together in the polymerization.
However, when an emulsifying agent and a suspending agent are used in combination, the fine resin particles obtained often have high hygroscopicity, which may lead to deterioration in electrical properties such as electrical insulation and the like. According to the method of the present invention, a dispersion liquid of heat-resistant resin particles having a relatively narrow particle size distribution can be easily obtained without using an emulsifier or a suspending agent. Examples of the emulsifier include anionic emulsifiers such as potassium oleate, sodium dodecylbenzene sulfonate and sodium lauryl sulfate; polyoxyethylene nonylphenyl ether, polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene sorbitan ester and the like. Nonionic emulsifiers; there are cationic emulsifiers such as lauryltrimethylammonium chloride, and examples of the suspending agent include polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, water-soluble salts of acrylic acid or methacrylic acid copolymers, the above nonionics. Suspensions such as organic emulsifiers;
Inorganic suspension agents such as magnesium carbonate, calcium carbonate, barium sulfate, etc. may be mentioned. Of these, one kind or two or more kinds may be appropriately used. It is also possible to use a publicly known pH adjuster, various salts, etc. as an auxiliary agent for maintaining stability during polymerization of fine particles or controlling particle diameter.

The molecular weight of the polymer obtained by the polymerization is not particularly limited, but it is preferably higher from the viewpoint of heat resistance.
When it is necessary to control the molecular weight, known chain transfer agents such as butyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol, carbon tetrachloride and the like may be used.

The heat-resistant fine resin particles contained in the resin dispersion obtained by the method of the present invention are spherical fine particles having a diameter in the range of 0.01 to 100 microns and a relatively narrow particle size distribution. It is also excellent in heat resistance, solvent resistance, slipperiness, electrical characteristics, etc., and it is hard, so making use of these characteristics, it can be used in various applications, such as heat resistance improver for various plastics, moldability improver and filling reinforcement. Alternatively, it can be used as a tape such as a magnetic tape or a slip agent for films.

Next, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to these Examples. The parts in the examples represent parts by weight, and% represents% by weight.

Example 1 270 parts of deionized water and 270 parts of butyl cellosolve were charged in the stainless steel flask equipped with a stirrer of Example 1, and heated to 50 ° C. in a nitrogen gas atmosphere and maintained at this temperature.
A solution prepared by dissolving 60 parts of N-ethylmaleimide and 0.6 parts of perbutyl H (manufactured by NOF CORPORATION) in 180 parts of butyl cellosolve was added to a 4-neck flask, and then 0.6 parts of Rongalit was added to start polymerization. It was Then the internal temperature is 70 ℃
The temperature was raised to and the polymerization was continued for 3 hours.

The obtained fine resin particle dispersion is an emulsion having a viscosity of 10 centipoise or less, and when the contained resin particles are observed with an electron microscope, they are spherical particles having a particle diameter of 0.1 to 10 microns. I understood it.

Further, the melting point measured by the METTLER melting point measuring device was 300 ° C. or higher.

Example 2 Deionized water 2 in a stainless steel flask equipped with a stirrer of 1
70 parts and 270 parts of butyl cellosolve were charged and heated to 60 ° C. in a nitrogen gas atmosphere and maintained at this temperature. N
A solution of 40 parts of cyclohexylmaleimide and 20 parts of methyl methacrylate dissolved in 180 parts of butyl cellosolve was added to the flask, and then 0.6 part of azobisisobutyronitrile was added to initiate polymerization. Then, the internal temperature was raised to 70 ° C., and polymerization was carried out at this temperature for 3 hours.

The obtained fine resin particle dispersion is a translucent emulsion having a viscosity of 10 centipoise or less, and the fine resin particles contained therein have a particle diameter of 0.1 to 10 as measured by an electron microscope.
It was found to be spherical particles in the micron range.

The melting point was 300 ° C or higher.

Example 3 Deionized water 2 in a stainless steel flask equipped with a stirrer of 1
70 parts were charged and heated to 90 ° C. under a nitrogen gas atmosphere and maintained at this temperature. N-phenylmaleimide 30
Part, perbutyl H (manufactured by NOF Corporation) 0.3 part in a solution of 270 parts cellosolve was added to the flask, and then 1.5 parts of 10% aqueous solution of Rongalit was added to initiate polymerization. After 1 hour from the start of the polymerization, 1.5 parts of a 10% Rongalit aqueous solution was added, and the polymerization was continued for 2 hours thereafter.

The obtained resin particle dispersion is a low-viscosity emulsion having a viscosity of 10 centipoise or less, and the resin particles contained therein are spherical particles having a particle diameter of 0.5 to 1.5 microns when observed with a microscope. I understood.

Moreover, the melting point was 300 ° C. or higher, and high heat resistance was exhibited.

Example 4 Deionized water 2 in a stainless steel flask equipped with a stirrer of 1
After 70 parts and 270 parts of cellosolve were charged and heated in a nitrogen gas atmosphere, 60 parts of N-cyclohexylmaleimide was added and dissolved.

Then, 0.6 part of Perbutyl H (manufactured by NOF CORPORATION) and 3 parts of a 10% aqueous solution of Rongalit were added to initiate polymerization. 1 hour after the start of polymerization, Rongalit 10% aqueous solution 3
Parts were added and the polymerization was continued for another 2 hours.

The obtained aqueous dispersion of fine resin particles is a low-viscosity emulsion having a viscosity of 10 centipoise or less, and the resin particles contained therein are spherical fine particles having a particle size in the range of 0.5 to 15 microns by microscopic observation. I knew it was.

Moreover, the melting point was 300 ° C. or higher, and high heat resistance was exhibited.

Claims (1)

[Claims] 1. A general formula (In the formula, R ₁ and R ₂ are each independently hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group or a substituted aryl group, and R ₃ is hydrogen, an alkyl group having 1 to 15 carbon atoms, cyclo An alkyl group, an aryl group or a substituted aryl group.), A polymerizable monomer containing a maleimide compound represented by the formula (1), an organic solvent capable of dissolving the polymerizable monomer and miscible with water. A method for producing a dispersion liquid of heat-resistant fine resin particles, which comprises polymerizing in an aqueous medium.