JPH03190905A - Production of spherical polymer particle - Google Patents

Abstract

PURPOSE:To obtain the title particles having low polymerization degree, a shape close to true sphere, uniform particle diameter and low-melt viscosity characteristics in polymerizing a monomer in a solvent which dissolves the monomer but not a polymer thereof, by using an azo-based hydrochloride as an initiator. CONSTITUTION:In polymerizing a monomer [e.g. methyl(meth)acrylate or methyl vinyl ether] in a solvent (e.g. lower alcohol such as methanol or n-hexane) to dissolve the monomer but not a polymer thereof, an azo-based hydrochloride [e.g. 2,2'-azobis(2-methyl-N-phenylpropionamidine) dihydrochloride] is used as an initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing truly spherical polymer particles having a low degree of polymerization.

[Background of the invention]

True spherical polymer particles can be used, for example, as raw materials for powder coatings, toners for electronic copying, as fillers for paints and cosmetics that exhibit good spreadability, as fillers for treatments such as adsorption treatment and ion exchange treatment that have high treatment efficiency, or as such fillers. It is currently attracting attention as a useful material for material carriers and fillers for imparting opalescent luster to plastic molded products.

[Conventional technology]

Conventionally, this type of truly spherical polymer particles has been produced using a precipitation polymerization method in which monomers are polymerized in a solvent that dissolves the monomers but does not dissolve the copolymer based on the monomers to precipitate the polymer. (Y, Almog et al., Polymer Journal Vol. 14, p. 131 (1982)
Year)).

Their method involves precipitation polymerization using a polymer soluble in the solvent together with a quaternary ammonium salt as a dispersion stabilizer to obtain truly spherical polymer particles with uniform particle size. Furthermore, attempts have been made to obtain truly spherical polymer particles with uniform particle diameters by dispersion polymerizing styrene in various solvents using nonionic cellulose derivatives as dispersion stabilizers (C, , Ober et al., Journal of Polymer Science, Vol. 23, p. 103 (1)
985)).

[Problem to be solved by the invention]

However, in the above-mentioned conventional method, the sphericity and uniformity of particle diameter of the polymer particles must be controlled very strictly, and there is a problem in that it is difficult to obtain a product with a low degree of polymerization.

[Means to solve the problem]

The present invention, as a means for solving the above-mentioned conventional problems,
Provided is a method for producing true spherical polymer particles using an azo hydrochloride as an initiator when the monomer is polymerized in a solvent in which the monomer is dissolved but the polymer based on the monomer is not dissolved. It is.

[Monomer]

Monomers used in the present invention include methyl acrylate, ethyl acrylate, n-butyl acrylate, 1
so-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 1so
-Butyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, 1so-butyl vinyl ether, n-butyl vinyl ether, styrene, α-
Examples include methylstyrene, acrylonitrile, methacrylaterile, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, ethylene, propylene, isoprene, chloroprene, and butadiene. ”−
The illustrative examples are not intended to limit the invention.

The above monomer may further contain a heavy substance having a functional group such as a carboxyl group, a hydroxyl group, a methylol group, an amino group, an acid amide group, or a glycidyl group. As for the heavy substances having the above functional groups, those having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, etc., and those having a hydroxyl group include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β- Hydroxypropyl methacrylate, allyl alcohol, etc. Those with a methylol group are N-methylol acrylamide, N-methylol methacrylamide, etc. Those with an amino group are dimethylaminoethyl acrylate-1-1-dimethylaminoethyl methacrylate, etc. Examples of those having an amide group include acrylamide and methacrylamide, and examples of those having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, and glycidyl allyl ether. The above examples are not intended to limit the invention.

Furthermore, in the present invention, monomers having a hydrolyzable silyl group, such as γ-
Methacryloxypropyltrimethoxysilane, vinyltriacetoxylan, vinyltrimethoxysilane, etc. can also be used. The above examples are also not intended to limit the invention.

Furthermore, in the present invention, a polyvalent vinyl compound containing two or more vinyl groups may be added as a monomer. Examples of the polyvalent vinyl compounds include divinylbenzene, diallyl phthalate, ethylene glycol dimethacrylate,
Examples include propylene glycol dimethacrylate and glycerin trimethacrylate.

The above-mentioned monomers, monomers having functional groups, and polyvalent vinyl compounds may be mixed alone or in combination, but the difference in sturdiness parameters between the monomers to be mixed is 1.
It is desirable that the

In addition, the above monomer is usually used at -0 to 65% by weight relative to the solvent.
Mixed to some degree.

〔solvent〕

The solvent used in this method is one that dissolves the above monomer but does not dissolve the copolymer based on the monomer, and is a lower alcohol such as methanol, ethanol, isopropanol, n-butanol, or Examples include a mixed solvent of lower alcohol and water, and nonpolar solvents such as n-hexane and n-hebutane. The above examples are not intended to limit the invention.

[Dispersion stabilizer]

As the dispersion stabilizer, polymers soluble in the above solvents are used, such as polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyvinyl alcohol, polyvinyl alkyl ether, etc. If desired, a surfactant may be used in addition to the above polymers. May be used in combination. Any of anionic, nonionic, and cationic surfactants can be used as the surfactant. Examples of anionic surfactants include higher alcohol sulfate (Na salt or amine salt), alkylaryl sulfonate (Na salt), and alkylaryl sulfonate (Na salt). ), alkylnaphthalene sulfonates, alkyl phosphates, dialkyl sulfosuccinates, rosin soaps, nonionic products such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol ethers, polyoxyethylene alkyl esters, polyoxyethylene alkyl amines ,
Polyoxyethylene alkyl amide, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, and cationic ones include trimethylaminoethyl alkylamide halide, alkylpyridinium sulfate, and alkyltrimethylammonium halide. The above examples are also not intended to limit the invention.

The above polymer is usually 0.5 to 20% by weight in the solvent, and the surfactant is usually 0.1 to 3% by weight in the solvent.
It is dissolved to some extent. Two or more kinds of the above-mentioned polymer and the above-mentioned surfactant may be mixed.

[Azo hydrochloride polymerization initiator]

The azo hydrochloride initiator of the present invention used in the polymerization of the co-applied polymer is 2,2'-azobis(2-methyl-N
-phenylpropionamidine) dihydrochloride, 2,2'-azobis[N-(4-chlorophenyl)=
2-Methylpropionamidine koshihydrochlorite, 2,2'-azobis[N-(4-hydroxyphenyl)-2-methylpropionamidine koshihydrochloride, 2,2'-azobis[N-(4-aminophenyl) -2-methylpropionamidinecotetrahydrochlorite, 2,2'-azobis[2-methyl-N-(
phenylmethyl)propionamidine koshihydrochloride, 2,2'-azobis[2-methyl-N-2-propenylpropionamidine koshihydrochloride,
2,2'azobis(2-methylpropionamidine) dihydrochlorite, 2,2'-azobis[N-(2-
hydroxyethyl)-2-methylpropionamidine koshihydrochloride, 2,2'-azobis[(2-
5-Methyl-2imidacillin-2-yl)propane koshihydrochlorite, 2,2'-azobis[2-(2-
imidacillin-2-yl)propane koshihydrochlorite, 2,2'-azobis[2-(4,5,6,7-teI-labitero-111-1.3-diazepin-2-yl)propane koshihydrochlorite light, 2゜2'-azobis[2-(3,4,5,6-tetrahydropyrimidin-2-yl)propane koshihydrochlorite, 2゜2'-azobis[2-(5-hydroxy-3, 4,5
, 6-tetrahydropyrimidin-2-yl)propane koshihydrochlorite, 2,2'-azobis(2-[
Examples include 1,-(2-hydroxyethyl)-2-imidacylin-2-ylcopropane)dihy-1 helochloride.

1) Azo hydrochloride may be used in combination with other polymerization initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethyl)valeronitrile, and benzoyl peroxide. may be done.

1. The azo hydrochloride polymerization initiator is usually added in an amount of about 0.1 to 8% by weight based on the comonomer.

〔polymerization〕

The mixture of the above monomer and the above solvent is polymerized using the above azo hydrochloride polymerization initiator by heating and stirring at a temperature of usually 50 to 80°C in a reactor equipped with a stirrer, a condenser, a thermometer, etc. . At this time, in order to smooth the polymerization, it is desirable to replace most of the air in the reactor with an inert gas such as nitrogen gas or argon gas.

As the monomer polymerizes, the monomer becomes a polymer and is precipitated in the solvent as true spherical particles. After completion of the polymerization, the obtained true spherical polymer particles are separated from the solvent by centrifugation or the like, washed if desired, and then dried at room temperature or with heating.

In this way, the true spherical polymer particles of the present invention are obtained, and the diameter of the true spherical polymer particles is influenced by the type of monomer and solvent, but is approximately in the range of about 0.5 to 10 μm. It becomes uniform.

[Effect]

When the monomer is polymerized using an azo hydrochloride as an initiator in a solvent in which the monomer dissolves but the polymer based on the monomer does not dissolve, 9-0 polymerization occurs using another azo initiator. A polymer with a lower degree of polymerization than that obtained is obtained.

Furthermore, the polymerization degree distribution is wider than that of polymers using other azo initiators. Furthermore, the polymer particles of the present invention have a shape close to a true sphere and a narrow particle size distribution.

〔Effect of the invention〕

Therefore, in the present invention, polymer particles with a low degree of polymerization, a nearly perfect spherical shape, and a uniform particle size can be obtained, and such polymer particles have low melt viscosity characteristics and can be used, for example, in electronic copying. Useful for toner, etc.

〔Example〕

Example 1 A reactor equipped with a stirrer, a condenser, a thermometer, and a gas inlet tube was filled with a solution of 4 parts by weight of polyvinylpyrrolidone dissolved in 160 parts by weight of isopropanol, and further 30 parts by weight of styrene and β-hydroxy Comonomer mixed with 2 parts by weight of ethyl methacrylate and 2,2'-azobis(2-methyl-N-phenylpropionamidine)
After dissolving 0.5 parts by weight of dihydrochlorite in 5 parts by weight of water and filling the tank with nitrogen replacement through the gas introduction pipe, the mixture was heated to 70°C for 24 hours while stirring and mixing at a rotation speed of 35 Orpm. Carry out polymerization. After the polymerization reaction, the resulting polymer particles were cooled to room temperature and collected separately, washed with isopropanol, and dried with ventilation at 60'C for 2 hours. The degree of polymerization of the polymer particles obtained in this way has a wide molecular weight distribution with a number average molecular weight of about 5,000 in terms of polystyrene and a dispersity of 30. When the particle size was measured using a scanning electron micrograph, it was found that the particles were perfectly spherical with a uniformly distributed particle size of 5.2±0.3 μm.

Example 2 In a reactor similar to that used in the example, 2,2'-azobis[N-(4-aminophenyl)-2-methyl was added to 1-60 parts by weight of ethanol in which 4 parts by weight of polyacrylic acid was dissolved. 0.5 parts by weight of propionamidine 1-la hydrochlorite was dissolved and filled, and a comonomer of 30 parts by weight of styrene and 1.5 parts by weight of divinylbenzene was further filled. The polymer particles obtained by polymerization were perfectly spherical with a uniformly distributed particle size of 2.5±065 μm.

Example 3 Polyvinyl methyl ether 3 was placed in a reactor similar to Example 3.
2,2'-
0.5 parts by weight of azobis[2-methyl-N-2-propenylpropionamidine koshihydrochlorite was dissolved and filled, 20 parts by weight of styrene, and 10 parts by weight of acrylonitrile.
parts by weight, and 2 parts by weight of dimethylaminoethyl methacrylate.The polymer particles obtained by polymerizing in the same manner as in Example 1 had a number average molecular weight of about 6,500 in terms of polystyrene, and were dispersed. The molecular weight distribution is wide with a degree of 30.
．． It was perfectly spherical with a uniformly distributed particle size of 3±0.2 μm.

Example 4 In a reactor similar to Example 1, 2,2'-azobis[(2-5-methyl-22- (imidacillin-2-yl)propane] Dihy 1 - 0.3 parts by weight of rochlorite, 0.2 parts by weight of 2,2'-azobisisobutyronitrile were dissolved and charged, and styrene 2
0 parts by weight, methyl methacrylate]-0 parts by weight, and 3 parts by weight of γ-methacryloxypropyl I-rimethoxysilane, and polymer particles obtained by polymerizing in the same manner as in Example 1. The number average molecular weight is approximately 8,500 in terms of polystyrene, and the degree of dispersion is 20, giving a wide molecular weight distribution of 3.0.
It was perfectly spherical with a uniformly distributed particle size of ±0.2 μm.

Claims (1)

[Claims] Production of truly spherical polymer particles characterized by using an azo hydrochloride as an initiator when polymerizing the monomer in a solvent in which the monomer is dissolved but the polymer based on the monomer is not dissolved. Method