JPH0350203A - Production of styrene polymer particle - Google Patents

Abstract

PURPOSE:To obtain polymer particles whose surfaces are not contaminated with polyvinyl alcohol by performing the polymerization in the presence of an amine compound in the suspension polymerization system in producing styrene polymer particles by using polyvinyl alcohol as a suspension stabilizer. CONSTITUTION:In the production of styrene polymer particles by suspension- polymerizing a styrene monomer together with optionally a copolymerizable monomer (at most 50% of the monomer phase) by using polyvinyl alcohol (desirably partially saponified PVA) as a suspension stabilizer in the presence of a polymerization initiator, the reaction is performed in the presence of an amine compound in the suspension polymerization system, desirably the dispersed phase (monomer phase). An amine compound slightly soluble in water (e.g. N-methylaniline), is desirable as the above amine compound and its amount of addition is 0.05-5%. desirably 0.1-3% in terms of a concentration in the dispersed phase.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to gap-maintaining agents, slipperiness-imparting agents, functional elements, monodisperse particles with surface activity, standard particles, toners, and fluidity and smoothness of paints. The present invention relates to a method for producing styrenic polymer particles used as a functional filler for controlling properties, and particularly to a method for producing styrenic polymer particles using polyvinyl alcohol (hereinafter referred to as PVA) as a suspension stabilizer.

[Prior Art] [Problem to be Solved by the Invention] Conventionally, when producing styrenic polymer particles, styrenic monomers were subjected to suspension polymerization in the presence of a polymerization initiator and a suspension stabilizer. There are various suspension stabilizers used here, and one of the most representative ones is PVA. Since this PVA is water-soluble and remains attached to the surface of the obtained styrenic polymer particles, the attached suspension stabilizer must be removed by washing or the like.

However, PVA, which is a suspension stabilizer, has a strong affinity with the surface of styrenic polymer particles, and its removal is very difficult, and sometimes a part of it is buried in the surface of styrenic polymer particles. Since the suspension stabilizer may be physically fixed to the particle surface, it is almost impossible to completely remove the suspension stabilizer by washing.

When using a poorly soluble solid fine powder such as tricalcium phosphate as a suspension stabilizer, there is a step of dissolving and removing the suspension stabilizer remaining on the surface of the resulting styrenic polymer particles using mineral acid or the like. Therefore, it is necessary to treat the polymerization equipment to be acid-resistant and to install special wastewater treatment facilities, which is disadvantageous in terms of cost.

The present invention aims to solve the above problems.

[Means for Solving the Problems] [Operation] The present invention has been made as a result of intensive research in view of the above circumstances.
In producing styrenic polymer particles using PVA as a suspension stabilizer, it has been found that by coexisting an amine compound in the suspension polymerization system, the surface of the styrenic polymer particles is less likely to be contaminated by PVA.

The outline of the present invention is a method for producing styrenic polymer particles by using a polymerizable monomer mainly consisting of a styrene monomer in the presence of a polymerization initiator and using polyvinyl alcohol as a suspension stabilizer. A method for producing styrenic polymer particles is characterized in that polymerization is carried out in the presence of an amine compound in the suspension polymerization system.

Next, each material used in the present invention and its effects will be described in detail.

The following percentages and parts are based on weight.

Styrenic polymerizable monomer styrene, 0-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert Styrene and derivatives thereof such as -butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, and divinylbenzene are used.

In addition, polymerizable monomers other than styrenic polymerizable monomers,
It also includes copolymerizations in which one or more types are added within a range of 50% or less in concentration in the heptamer phase.

The monomers to be copolymerized include ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl butylene; vinyl acetate; , organic acid vinyl esters such as vinyl propionate and vinyl benzoate; methacrylic acid, methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. Methacrylic acid and its derivatives; acrylic acid, methyl acrylate, ethyl acrylate, acrylic acid n
- Acrylic acid and its derivatives such as butyl, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinylmethyl Vinyl ethers such as ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone, N-vinylpyrrole, N-vinylcarbazole, N-
Examples include N-vinyl compounds such as vinyl indole and N-vinylpyrrolidone; vinylnaphthalenes; and polymerizable monomers such as acrylonitrile, methacrylonitrile, and acrylamide.

As a polymerization initiator, 2.2''-azobisisobutyronitrile, 2.2°-azobis-(2,4 dimethylvaleronitrile), 2.2'-azobis-4-methoxy-2
, 4-dimethylvaleronitrile, and other azo or diazo polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate, and other peroxide polymerization initiators.

By using two or more kinds of polymerization initiators in combination, it is possible to control the molecular weight and molecular weight distribution of the polymer, and to control the polymerization reaction time.

Further, a water-soluble polymerization initiator such as ammonium persulfate or potassium persulfate may be used in combination if necessary.

Partially saponified PVA, which is a suspension stabilizer, is useful for suspension polymerization, but contamination of polymer particles, particularly the formation of a PVA film, is noticeable.

Therefore, by adding an amine compound to this polymerization system, contamination by PVA can be suppressed and prevented, and examples of the amine compound include the following.

Aniline, N-methylaniline, N-ethylaniline,
N,N-dimethylaniline, N,N-diethylaniline, 2-methylaniline, 2-ethylaniline, 3-methylaniline, 3-ethylaniline, 4-methylaniline, 4-ethylaniline, 2-nitroaniline, 3 -Nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,2-dinitroaniline, 2-chloroaniline, 3-chloroaniline, 4-chloroaniline, 2゜4
-dichloroaniline, 2,2-dichloroaniline, 0-
Aniline derivatives such as phenylenediamine, m-phenylenediamine, p-phenylenediamine, methylamine,
Ethylamine, ethanolamine, 1-propylamine, 2-propylamine, 1-butylamine, 2-butylamine, 3-butylamine, 1-pentylamine, 1-
Aliphatic amine derivatives such as hexylamine, 1-hebutylamine, 1-octylamine, and ethylenediamine are used. These amines can be used alone or in combination.

When using an amine compound in the present invention, by adding it to the dispersed phase (monomer phase), P is applied to the surface of the polymer particles.
It was possible to prevent contamination of VA.

In this case, the amine compound is preferably one that is slightly soluble in water, and can be added to either the dispersed phase (monomer phase) or the continuous phase (aqueous phase), or both, but especially by adding it to the dispersed phase. , it is possible to obtain a large pollution control effect.

When the amine compound used in the present invention is added to the dispersed phase, the concentration in the phase is 0.05% to 5%, preferably 0.1% to 3%.

When the concentration of the amine compound is less than 0.05%, contamination of PVA is observed, and when it exceeds 5%, there is a strong tendency to inhibit polymerization, making it impossible to obtain a polymer with the desired molecular weight.

In addition, due to the problems of cleaning and drying the polymer particles, this pollution prevention effect becomes more effective as the particle size of the polymer particles becomes smaller, and is particularly effective when the particle size of the polymer is about 1 to 100 μm. It is.

〔Example〕

Examples will be described below.

Example 1 Completely saponified PVA (degree of polymerization 1700, acetic acid group 1 mol%)
), partially saponified PVA (degree of polymerization 1700, acetic acid group 10 mol%) Ig was dissolved in 250 ml of water to prepare a continuous phase. A dispersed phase prepared by dissolving Ig benzoyl peroxide and 1 g of N-methylaniline in 100 g of styrene was added to the continuous phase, and the mixture was dispersed for about 20 minutes at 110,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Adjust the suspension. This suspension is added to a 500 ml round-bottom three-bottle flask equipped with a stirrer, a temperature needle, and a reflux condenser, heated to 80°C, and stirred for about 8 hours to the extent that droplets do not precipitate to polymerize. . After polymerization, treatment was performed by a conventional method to obtain polymer particles. When the particle size of the obtained polymer particles was measured using a Coulter counter (aperture 100I!l11), the volume average particle size of the polymer particles was 1.
It was 011m. When this polymer particle was observed using a scanning electron microscope, no PVA contamination was observed on the particle surface as shown in the SEM photograph (FIG. 1).

Example 2 Polymer particles were obtained in the same manner as in Example 1, except that 0.6 g of 4-nitroaniline was used as the amine compound and 1 g of 2,2-azobisisobutyronitrile was used as the polymerization initiator. When the particle size of the obtained polymer particles was measured using a Coulter counter (aperture 100 μm+), the volume average particle size of the polymer particles was 10 μm. When this polymer particle was observed with a scanning electron microscope, no PVA contamination was observed on the particle surface as in the SEM photograph (FIG. 1).

Example 3 After partially dispersing 90 g of styrene, 10 g of n-butyl acrylate, and 20 g of carbon blank (manufactured by Mitsubishi Kasei) at room temperature for about 1 hour using a paint conditioner, the mixture was placed in a separable flask and heated with nitrogen for about 30 minutes. After gas replacement, the carbon black was surface-treated with the polymerizable monomer at 100° C. or higher to obtain surface-treated carbon black.

Polymer particles were obtained in the same manner as in Example 1, except that 10 g of the surface-treated carbon blank and 3 g of 2,2-azobisisobutyronitrile were added as a polymerization initiator to the dispersed phase.

When the particle size of the obtained polymer particles was measured using a Coulter counter (aperture 100 μm), the volume average particle size of the polymer particles was 12 μm. When this polymer particle was observed under an optical microscope, each particle of the polymer particle had a nearly completely black spherical shape, and no uneven distribution of carbon black was observed within the polymer particle.

Further, when this polymer particle was observed using a scanning electron microscope, no PVA contamination was observed on the particle surface as in the SEM photograph (FIG. 1).

Comparative Example Polymer particles were produced by suspension polymerization in the same manner as in Example 1, except that no amine compound was added. When the particle size of the obtained polymer particles was measured using a Coulter counter (aperture 100 μm),
The volume average particle diameter of the polymer particles was 19 μm. When this polymer particle was observed with a scanning electron microscope, it was found that SE
As shown in the M photograph (Fig. 2), PVA contamination was confirmed on the particle surface.

〔Effect of the invention〕

In the present invention, by adding an amine compound to the suspension polymerization system, it is possible to easily obtain polymer particles whose particle surfaces are not contaminated with PVA, which is a suspension stabilizer.

[Brief explanation of drawings]

FIG. 1 is an electron micrograph showing the structure of polymer particles obtained by the present invention, and FIG. 2 is an electron micrograph showing the structure of polymer particles obtained by a conventional method.

Claims (1)

[Claims] In a method for producing styrenic polymer particles by using a polymerizable monomer mainly composed of a styrenic monomer in the presence of a polymerization initiator and using polyvinyl alcohol as a suspension stabilizer, the suspension polymerization A method for producing styrenic polymer particles, characterized in that polymerization is carried out in the coexistence of an amine compound in the system.