JPS61250010A - Production of fine particle of heat-resistant resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin particles having excellent heat-resistance and solvent-resistance, by carrying out the emulsion polymerization of a monomer composition containing a specific maleimide compound in a hydrophobic organic solvent capable of dissolving the monomer and unable to dissolve the produced polymer, separating the produced polymer from the reaction liquid and drying the polymer. CONSTITUTION:A polymerizable monomer composition containing a maleimide compound of formula (R1 and R2 are H, halogen, 1-15C alkyl, aryl or substituted aryl; R3 is H, 1-15C alkyl, cycloalkyl, aryl or substituted aryl) (e.g. N-phenylmaleimide) is dissolved in a hydrophobic organic solvent (e.g. toluene) capable of dissolving said polymerizable monomer and unable to dissolve the produced polymer. The solution is subjected to emulsion polymerization or suspension polymerization, and the produced polymer particles are separated from the resultant emulsion or suspension and dried to obtain the objective fine resin particles.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing fine resin particles having excellent heat resistance and solvent resistance. The particle size is 100 microns or less by turbidity polymerization,
The present invention relates to a method for obtaining heat-resistant resin particles having a relatively narrow particle size distribution.

Fine resin particles have traditionally been widely used as pigments, extender pigments, and filling reinforcing agents for plastics, but some of these particles lack sufficient heat resistance or solvent resistance, or generate decomposition gas. The current situation is that we have a problem.

In view of these circumstances, the present inventors conducted intensive research and found that a polymerizable monomer containing a maleimide compound was dissolved in a specific organic solvent and subjected to emulsion polymerization or suspension polymerization. Separate polymer particles from emulsion or suspension,
It was discovered that by drying, fine resin particles with a particle size of 100 microns or less, a relatively narrow particle size distribution, and excellent heat resistance and solvent resistance could be easily obtained, and this led to the completion of the present invention. This is what we have come to.

That is, the present invention relates to the general formula (wherein R1 and R2 are each independently hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group, or a substituted aryl group, and R3 is hydrogen or a substituted aryl group having 1 to 15 carbon atoms). (alkyl group, cycloalkyl group, aryl group, or substituted aryl group) is dissolved in a polymerizable monomer containing a maleimide compound represented by After carrying out emulsion polymerization or suspension polymerization of a solution obtained by dissolving the polymer obtained by polymerization in a hydrophobic organic solvent that does not dissolve it, separating and drying the polymer particles from the obtained emulsion or suspension. The present invention relates to a method for producing heat-resistant fine resin particles characterized by the following.

The maleimide compound used in the present invention is represented by the above general formula, and includes, for example, maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, and N-isobutylmaleimide. Maleimide, N-tert-butylmaleimide, N-cyclohexylmaleimide, N-laurylmaleimide, N-phenylmaleimide, N-(2
-chlorphenyl)maleimide, N-(3-chlorphenyl)maleimide, N-(4-lylphenyl)maleimide, N-(4-promofinyl)maleimide, N-(
2,4,6-dolychlorophenyl)maleimide, N-(
2゜4,6-Tribromofinyl)maleimide, N-
(2-methylphenyl)maleimide, N-(3-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2-tert-butylphenyl)maleimide, N-(3-tert-butylphenyl) Maleimide, N-(4-tert-butylphenyl)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-
(4-7Inilphinyl)maleimide, N-(4-7enyloxyphenyl)maleimide, N-(4-benzylphenyl)maleimide, N-(4-benzyloxyphenyl)maleimide, N-(4-phenoxy methylphenyl)
Maleimide, N-(2-chloro-4-phenoxyphenyl)maleimide, N-naphthylmaleimide, N-(2-
Examples include carboxyphenyl)maleimide, N-(4-carboxyphenyl)maleimide, α-chloro-N-phenylmaleimide, α-methyl-N-phenylmaleimide, and one or more of these can be used. You can.

The polymerizable monomer used in the present invention contains the above-mentioned maleimide compound, and takes into consideration the required heat resistance and solvent resistance, and impairs the heat resistance and solvent resistance of the resulting fine resin particles. Other monomers copolymerizable with the maleimide compound may be used in combination with the maleimide compound. Preferably, the maleimide compound is used in combination with other monomers in such a proportion that it becomes the main component of the polymerizable monomer. If the amount of other monomers used exceeds the ratio in which the maleimide compound is the main component of the polymerizable monomer, the heat resistance of the resulting resin particles may become insufficient, or the resulting emulsion may become insufficient. Alternatively, complicated operations when separating and drying polymer particles from a suspension, such as spray drying or drying a low-compression cake at a relatively low temperature (less than 100°C), may cause disintegration of the polymer particles. Care must be taken, as it may be necessary to facilitate the preparation and obtain fine resin particles with a desired particle size.

Examples of these other monomers include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, Alkyl groups with 1 to 18 carbon atoms such as octyl methacrylate, 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, 3-phenylpropyl methacrylate, etc. Methacrylic esters with methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, amyl acrylate, isoamyl acrylate, octyl acrylate, acrylic acid Acrylic esters having an alkyl group of 1 to 18 carbon atoms such as 2-ethylhexyl, decyl acrylate, lauryl acrylate, hexyl acrylate, and benzyl acrylate: styrene, α-methylstyrene, paramethylstyrene, vinyl Vinyl aromatics such as toluene, isopropenylstyrene, and styrene; unsaturated nitriles such as acrylonitrile, methacrylaterile, ethacrylonitrile, and phenylacrylonitrile; ethylene glycol diacrylate or methacrylate, hexanediol diacrylate or methacrylate, divinyl Benzene, 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, halogenated bisphenol A
polyhydric acrylates or methacrylates such as diacrylates or methacrylates of ethylene oxide or propylene oxide adducts, triacrylates or methacrylates of isocyanurates, di- or triacrylates or methacrylates of ethylene oxide or propylene oxide adducts of isocyanurates; Polyvalent arylates such as allyl isocyanurate and diallyl phthalate; and functional monomers such as glycidyl acrylate or methacrylate, allyl glycidyl ether, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, or half esters thereof. Depending on the purpose, one or more of these can be used, and the types and amounts used may be selected within the scope of the purpose of the present invention.

The heat-resistant fine resin particles obtained by the method of the present invention are 0.01
They are spherical fine particles with a size of ~100 microns.

The particles can be easily obtained through emulsion polymerization or suspension polymerization of the polymerizable monomers described above, but during polymerization,
It is obtained by polymerizing a solution in which the polymerizable monomer is dissolved in a hydrophobic organic solvent that dissolves the polymerizable monomer but does not dissolve the polymer by the polymerization method described above.

Most maleimide compounds are solid at room temperature. For this reason, conventional methods have various limitations when carrying out emulsion polymerization or suspension polymerization of monomers containing maleimide compounds as a main component. For example, it may be necessary to heat the maleimide compound to a temperature higher than its melting point and then bring it into an emulsified or suspended state before polymerization, or to dissolve the maleimide compound in an unnecessarily large amount of other polymerizable monomers before polymerizing. In addition, there is no restriction that the process becomes complicated, such as requiring complicated operations to control the particle size distribution of the resulting fine resin particles. The method of the present invention, in which polymerization is carried out after the reaction, does not suffer from the disadvantages of methods that do not use organic solvents.

That is, polymerization can proceed at any polymerization temperature regardless of the melting point of the maleimide compound, and since the organic solvent does not dissolve the polymer, polymer particles can be removed from the resulting emulsion or suspension by filtration, etc. Even during separation, the polymer particles do not fuse together, making it extremely easy to control the particle diameter of the resin particles finally obtained.

In the conventional method, when polymerizing at a high temperature higher than the melting point of the maleimide compound, the emulsion or suspension polymerization system becomes unstable and fine resin particles with the desired particle size can be obtained, but the heat resistance of the fine resin particles is inferior. On the other hand, according to the method of the present invention,
Fine resin particles with a desired particle size can be easily obtained even from polymerizable monomers containing a high proportion of maleimide compounds with a high melting point, and as a result, it is possible to make resin particles with extremely high heat resistance. Become.

The concentration of the polymerizable monomer in an organic solvent solution depends on the type of monomer and the amount of
Although it depends on the type of solvent and the temperature at the time of dissolution, conditions may be appropriately selected in consideration of the particle size of the obtained polymer, polymerization conditions for the molecule m1 of the polymer, economic efficiency, etc. For example, various methods can be selected, such as the case where the monomer is dissolved in a solvent at room temperature and then polymerized, or the case where the monomer is dissolved under heating and then polymerized.

The organic solvent used in the present invention is particularly a hydrophobic organic solvent that dissolves the polymerizable monomer containing the maleimide compound but does not dissolve the polymer obtained by polymerizing the polymerizable monomer. For example, without limitation, hexane, heptane, cyclohexane, decane, benzene, toluene, xylene,
Aliphatic or aromatic hydrocarbons such as ethylbenzene, p-cymene, decalin, and solvent naphtha; Halogenated hydrocarbons such as chloroform and tricOOethane Niamyl alcohol, n-butanol, 5eC-butanol, n
- Alcohols such as hexanol, cyclohexanol, and benzyl alcohol; ketones such as methyl isobutyl ketone, isophorone, and methyl cyclohexanone; esters such as butyl acetate, isobutyl acetate, methyl acetoacetate, ethyl acetoacetate, butylcarpitol acetate, etc. These can be used alone or in combination of two or more.

The polymerization reaction is carried out under autogenous pressure or under pressure under an inert gas atmosphere at temperatures ranging from 0°C or lower to 100°C or higher. .

The polymerization initiators used in the polymerization include conventionally known free radical polymerization initiators such as oil-soluble or water-soluble peroxides such as benzoyl peroxide, lauryl peroxide, hydrogen peroxide, potassium persulfate, and ammonium persulfate. Azo compounds such as azobisisobutyronitrile are suitable. It is also possible to use a reducing agent such as dimethylaniline, sodium bisulfite, ascorbic acid, ferrous sulfate, etc. in combination to effectively advance the polymerization reaction.

Examples of emulsifiers used during emulsion polymerization include anionic emulsifiers such as potassium oleate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate;
Nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene polyoxypropylene block copolymer, polyoxyethylene sorbitan ester; cationic emulsifiers such as lauryl trimethyl ammonium chloride may be used as appropriate; Preference is given to using primarily anionic emulsifiers.

Suspending agents used in suspension polymerization include, for example, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, water-soluble salts of acrylic acid or methacrylic acid copolymers, organic suspending agents such as the above-mentioned nonionic emulsifiers, magnesium carbonate, Examples include inorganic suspending agents such as calcium carbonate and barium sulfate.

Although there is no particular restriction on the molecular weight of the polymer obtained by polymerization, a higher molecular weight is preferable from the viewpoint of heat resistance.

If it is necessary to adjust the molecular weight, a known chain transfer agent such as butyl mercaptan, tertiary dodecyl mercaptan, mercaptoethanol, carbon tetrachloride, etc. may be used.

Further, for the purpose of maintaining the stability of particles during polymerization and adjusting the particle size tsm, known pH adjusters, various salts, etc. can be used auxiliary.

To obtain fine resin particles from the polymer emulsion or suspension obtained as described above, the polymer particles may be separated and dried according to a conventional method. After adding electrolytes and salting out fine mti combined particles, it goes through the steps of filtration, water washing, and drying; when it simply goes through the steps of filtration, water washing, and drying; or when it uses spray drying. Any method can be adopted.

Furthermore, in the present invention, when obtaining polymer particles by using a large amount of maleimide compound in a proportion that becomes the main component of the polymerizable monomer,
This is particularly preferred because the polymer particles can be easily crushed without complicated separation and drying. That is, it is preferable to rapidly dry the filter cake obtained under reduced pressure from the viewpoint of making the apparatus more compact and shortening the process. More preferably 50-1
Even when drying a highly compressed cake by drying it under reduced pressure at a temperature of 00°C, volatile components such as organic solvents and water in the cake are vaporized, drying is complete, and the polymer particles are extremely easy to disintegrate. Become.

The heat-resistant fine resin particles obtained by the method of the present invention have a diameter of 0.
．． They are spherical fine particles in the range of 0.01 to 100 microns. Since it is preferable for the particle size distribution of the fine resin particles to be narrow in practical terms, the particle size distribution can be adjusted by adjusting the type of organic solvent, polymerization temperature, polymerization initiator, emulsifier or suspending agent, monomer concentration,
Resin particles having a predetermined particle size distribution range may be obtained by combining various requirements such as auxiliary agents and stirring.

The fine resin particles obtained by the method of the present invention have a relatively narrow particle size distribution, have excellent heat resistance, solvent resistance, lubricity, electrical properties, etc., and are hard, so they can be used for various purposes by taking advantage of these characteristics. For example, it can be used as a heat resistance improver for various plastics, a molding processability improver, a filling reinforcing agent, a slip agent for tapes such as magnetic tape, and films.

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

Example 1 411 parts of deionized water and 3 parts of sodium lauryl sulfate were charged into a 11-piece stainless steel four-loaf flask equipped with a stirrer.
Under a nitrogen gas atmosphere, four solutions prepared by dissolving 124 parts of 60°C in 76 parts of toluene at 60°C were added to a Lof flask and emulsified. After raising the internal temperature to 70℃, add “
Polymerization was initiated by adding 0.6 parts of Verbutyl HJ (manufactured by NOF Corporation) and 0.6 parts of 0 Ngalit as a reducing agent, then maintained at 70°C for 2 hours, and further maintained at 80°C for 1 hour.

The obtained emulsion was heated to 50°C and 1g of 30II111'
Toluene and water were removed and dried under reduced pressure conditions.

When the obtained fine resin particles were observed using an electron microscope, they were found to be spherical particles with a particle size in the range of 0.1 to 0.3 microns. Further, the fine resin particles had a melting point of 300° C. or higher (Mettler melting point meter) and did not dissolve in toluene.

Example 2 566.5 parts of deionized water and 5 parts of sodium dodecylbenzenesulfonate were placed in 114 stainless steel flasks equipped with a stirrer, and heated to 50°C under a nitrogen gas atmosphere to dissolve the dodecylbenzene part and methyl methacrylate. 67.5
1 and “Perbutyl HJ (NOF@1i) 1.25
Four parts of the solution in which 1 part was dissolved in 25 parts of cyclohexane and 5 parts were added to a Lof flask and emulsified. Next, an aqueous solution of 1.25 parts of Rongalite dissolved in 10 parts of deionized water was added to initiate polymerization, and then the internal temperature was raised to 60°C and maintained at this temperature for 3 hours. During this time, 2 parts of Rongalite aqueous solution was added in 6 portions to complete the polymerization.

The resulting emulsion was diluted with deionized water to a concentration of 10%, and then a 3% aqueous aluminum sulfate solution was gradually added under stirring to precipitate the polymer. After removing the supernatant, the process of washing with deionized water was repeated twice, and then heated at 50°C.
Dry under reduced pressure of 50aa+HC1.

As a result of observing the obtained fine resin particles with an electron microscope, they were found to be spherical particles with a particle size in the range of 0.1 to 0.3 microns. Further, the fine resin particles had a melting point of 300° C. or higher and did not dissolve in cyclohexane.

Example 3 500.3 parts of an aqueous solution prepared by dissolving 0.3 parts of polyvinyl alcohol in 500 parts of deionized water was placed in a stainless steel flask equipped with a stirrer, and the mixture was heated to 500.3 parts under a nitrogen gas atmosphere.
Warmed to ℃. Next, a solution containing 0.5 parts of azobisisobutyronitrile and 0.5 parts of azobisisobutyronitrile was charged into a flask and uniformly suspended. After increasing the internal temperature of the flask to 65°C and maintaining this temperature for 3 hours, the internal temperature was further increased to 75°C and 1
Holds time.

The resulting aqueous suspension was dried at 50° C. under reduced pressure with 11 g of 50 ml, washed twice with deionized water, and dried in a lh air dryer at 120° C. to obtain fine resin particles. .

When the obtained fine resin particles were observed with an optical microscope, it was found that
It was found that the particles were spherical particles with a particle diameter in the range of 10 to 30 microns. Moreover, the melting point was 300'C or higher.

Claims (1)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. hydrogen, an alkyl group having 1 to 15 carbon atoms, a cycloalkyl group, an aryl group, or a substituted aryl group. is subjected to emulsion polymerization or suspension polymerization of a solution in which the polymer obtained by polymerizing the polymerizable monomer is dissolved in a hydrophobic organic solvent that does not dissolve the polymer obtained. A method for producing heat-resistant fine resin particles, characterized by separating and drying the combined particles.