JPH10251332A - Crosslinked polymer particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject particles excellent in heat resistance, solvent resistance, etc., and useful as a filler for coatings, cosmetics, etc., by hydrolyzing silyl groups contained in the particles of the copolymer of one or more silyl group-containing vinylic monomers with one or more other vinylic monomers to produce the crosslinked polymer particles. SOLUTION: Silyl groups contained in the particles of the copolymer of one or more hydrolyzable silyl group-having monomers of the formula (R is a divalent hydrocarbon such as a 1-10C alkyl or an aryl; X is a hydrolyzable group such as an alkoxy or a halogen), etc., with one more other vinylic monomers capable of being copolymerized with the vinylic monomers of the formula are hydrolyzed to produce the objective crosslinked polymer particles useful as a medium for adsorption and substance exchange.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to crosslinked polymer fine particles particularly useful as a medium for adsorption or substance exchange treatment.

[0002]

BACKGROUND OF THE INVENTION Spherical polymer powders are used, for example, for powder coating materials, toner for electronic copying, fillers for paints and cosmetics exhibiting good spreadability, and adsorption and ion exchange treatments with high treatment efficiency. Currently, it is being spotlighted as useful as a filler or a filler for imparting an opal-like gloss to a carrier of the filler, a plastic molded product, or the like.

[0003]

2. Description of the Related Art Conventionally, a spherical polymer powder of this type disperses in a solvent in which a monomer is dissolved and a copolymer based on the monomer is not dissolved. It is known that it can be obtained by the John polymerization method (Y.
Almog et al., Polymer Journal Vol. 14, p. 131 (1982)). Their method is the fourth as a dispersion stabilizer.
Dispersion polymerization is performed using a polymer dissolved in the solvent together with a quaternary ammonium salt to obtain a spherical polymer powder having a uniform particle size. Further, by performing dispersion polymerization of styrene in various solvents using a nonionic cellulose derivative as a dispersion stabilizer,
It has also been attempted to obtain a spherical polymer powder having a uniform particle size (CK Over, et al., Journal of Polymer Science, Vol. 23, p. 103 (1985)). Further, as another method for producing a spherical polymer powder, there is a seed polymerization method in which a predetermined monomer is absorbed into the polymer fine particles using the polymer fine particles as a seed, and then the monomer is polymerized (Japanese Patent Laid-Open Publication No. H10-163873). No. 61-215602).

[0004]

As described above, the thus obtained spherical polymer powder having a uniform particle size is used as a filler for paints and cosmetics, and for filling for processing such as adsorption treatment or ion exchange treatment. It is used as a material, but when the polymer powder does not have a cross-linked three-dimensional structure, heat resistance and solvent resistance are poor, and the range of use is significantly limited. However, when a divinyl compound such as divinylbenzene or diallyl phthalate is added to the comonomer to impart a crosslinked three-dimensional structure to the polymer powder, the sphericity and uniformity of the particle size of the polymer powder are reduced. Would.

[0005]

According to the present invention, as a means for solving the above-mentioned conventional problems, a vinyl monomer having a hydrolyzable silyl group, alone or in combination of two or more, is used. Another object of the present invention is to provide crosslinked polymer fine particles in which a silyl group contained in a fine particle of a copolymer with another copolymerizable vinyl monomer alone or two or more types is hydrolyzed to form a crosslink.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

[Vinyl monomer having a hydrolyzable silyl group] In the vinyl monomer having a hydrolyzable silyl group used in the present invention, the hydrolyzable silyl group has the following structure. Wherein R is an alkyl group having 1 to 10 carbon atoms, an aryl group, a divalent hydrocarbon group, X is for example -OCH _3, alkoxyl groups such as -OC ₂ H ₅ selected from aralkyl, -C
It is a hydrolyzable group such as halogen such as l, -Br.
Specific examples of the vinyl monomer having a hydrolyzable silyl group include γ-methacryloxypropyltrimethoxysilane and N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane. -Hydrochloride, vinyltriacetoxysilane, vinyltrimethoxysilane and the like.

[Vinyl monomer] Other vinyl monomers copolymerizable with the above-mentioned vinyl monomer having a hydrolyzable silyl group include methyl acrylate, ethyl acrylate, n
-Butyl acrylate, iso-butyl acrylate,
2-ethylhexyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, 2-
Ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, iso-butyl vinyl ether, n-butyl vinyl ether, styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, chloride Vinyl monomers such as vinylidene, vinyl fluoride, vinylidene fluoride, ethylene, propylene, isoprene, chloroprene, butadiene, and functional groups such as carboxyl group, hydroxyl group, methylol group, amino group, acid amide group and glycidyl group It is also possible to use a vinyl monomer having Among the vinyl monomers having such a functional group, those having a carboxyl group include acrylic acid, methacrylic acid, and itaconic acid, and those having a hydroxyl group include β-hydroxyethyl acrylate and β-hydroxyethyl acrylate.
Hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, allyl alcohol, etc. , Such as dimethylaminoethyl methacrylate, acrylamide and methacrylamide as those having an acid amide group, glycidyl acrylate as those having a glycidyl group,
Glycidyl methacrylate, glycidyl allyl ether and the like are exemplified. The above examples do not limit the invention. Further, in the present invention, a monomer having a hydrolyzable silyl group as a functional group as a vinyl monomer having a functional group, for example, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, etc. Can also be used. The above examples also do not limit the present invention.

[Commonomer] The above-mentioned hydrolyzable silyl group-containing vinyl monomer alone or as a mixture of two or more thereof is mixed with the other vinyl monomer alone or as a mixture of two or more thereof. The above-mentioned vinyl monomer having a hydrolyzable silyl group is preferably contained in the above-mentioned comonomer in an amount of 0.01 to 30 mol%, more preferably the above-mentioned vinyl monomer. Among them, the vinyl monomer having the above functional group is contained in an amount of 0.2 to 7 mol%.

[Production Method] Desirable production methods are a precipitation polymerization method and a seed polymerization method. A precipitation polymerization method In the precipitation polymerization method, the vinyl monomer having a hydrolyzable silyl group alone or a mixture of two or more thereof, and a vinyl monomer having a hydrolyzable silyl group, A comonomer consisting of a single or a mixture of two or more vinyl monomers, such that the comonomer is soluble and the copolymer based on the comonomer is insoluble Polymerize in a solvent. By such polymerization, the copolymer is precipitated in the solvent as spherical particles having a uniform particle size.

(Solvent) The solvent used in the present method is one in which the above-mentioned comonomer dissolves and the copolymer based on the comonomer does not dissolve, and methanol, ethanol, isopropanol, n- A lower alcohol such as butanol, or a mixed solvent of the lower alcohol and water, or n-
Non-polar solvents such as hexane and n-heptane are exemplified. The above examples do not limit the invention.

(Dispersion stabilizer) As the dispersion stabilizer, a polymer soluble in the above-mentioned solvent, for example, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyvinyl alcohol, polyvinyl alkyl ether, etc. is used. In addition to the above, a surfactant may be used in combination. As the surfactant, any of anionic, nonionic and cationic surfactants can be used. For example, as anionic one, higher alcohol sulfate (Na salt or amine salt), alkyl allyl sulfonate (Na salt), alkyl naphthalene sulfonate, alkyl phosphate, dialkyl sulfosuccinate, rosin soap, nonionic Examples include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine,
Examples of polyoxyethylene alkyl amide, sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, and cationic ones include trimethylaminoethylalkylamide halogenide, alkylpyridinium sulfate, and alkyltrimethylammonium halogenide. The above examples also do not limit the invention. The polymer is usually 0.5 to 5% by weight in the solvent,
The surfactant is usually dissolved in the solvent in an amount of about 0.1 to 1% by weight. The polymer and the surfactant may be used in combination of two or more.

(Polymerization) As the polymerization initiator used for the polymerization of the above comonomer, oil-soluble initiators such as lauroyl peroxide, benzoyl peroxide, cumene hydroperoxide, azobisisobutyronitrile and the like are used. .
The oil-soluble initiator is usually used in an amount of 0.1 to 2 based on the above comonomer.
It is added in the order of% by weight. The above comonomer is usually mixed in an amount of about 10 to 30% by weight with respect to the above solvent. The mixture of the above comonomer and the above solvent is then polymerized using the above oil-soluble initiator, usually by heating and stirring at about 50 to 80 ° C. in a reactor equipped with a stirrer, condenser, thermometer and the like. At this time, it is desirable to replace most of the air in the reactor with an inert gas such as nitrogen gas or argon gas in order to smooth the polymerization. As the comonomer polymerizes, the monomer becomes a polymer and precipitates out in the solvent as a true spherical powder. After completion of the polymerization, the obtained spherical polymer powder is separated from the solvent by filtration, centrifugation, or the like, washed if necessary, dried at room temperature or heated. Thus, the spherical polymer powder of the present invention is obtained. The diameter of the spherical polymer powder is affected by the type of the comonomer and the solvent, but is in the range of about 1 to 10 μm and is uniform. It becomes something.

B seed polymerization method In the seed polymerization method, polymer fine particles and a swelling agent for the polymer fine particles are dispersed in water to prepare a swelling aqueous dispersion of the polymer fine particles, and the aqueous dispersion is added to the aqueous dispersion. A copolymer comprising a single or a mixture of two or more kinds of vinyl monomers having a hydrolyzable silyl group and a mixture of one or more kinds of other vinyl monomers copolymerizable with the vinyl monomer. The monomers are mixed, the comonomer is absorbed by the swollen body of the polymer fine particles, and polymerization is performed. By such polymerization, the copolymer is collected as true spherical particles having a uniform particle size, similarly to the precipitation polymerization method.

(Polymer Fine Particles) The polymer fine particles used as seeds are fine particles of a polymer swellable in an organic solvent as a swelling agent, and include polystyrene, polymethacrylate, polyacrylate, polyvinyl chloride, polyvinyl acetate, and polyacrylonitrile. , styrene - butadiene copolymers and the like, the particle diameter of the polymer particles is desirably at normal 1μm hereinafter are about 0.2～0.9Myuemu.

(Swelling Agent) As swelling agents for the above polymer fine particles, methanol, ethanol, n-butanol, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone, toluene, xylene, n-hexane, n-heptane, n-heptane Organic solvents such as octane, methylene chloride, 1,2-dichloroethane, 1,2,3-trichloroethylene, 1-chlorododecane, dimethylformamide, and tetrahydrofuran are exemplified. Desirable organic solvents having a solubility in water of 0.02% by weight or less are desirable. A solvent is used. Two or more swelling agents may be mixed.

(Comonomer) The comonomer used in the present method is a vinyl monomer having a hydrolyzable silyl group similar to the comonomer used in the precipitation polymerization method, and the vinyl monomer It is a mixture with other vinyl monomers copolymerizable with the polymer.

(Polymerization) In the polymerization, usually, first, the polymer fine particles are dispersed in water, and then the swelling agent is dispersed in the water, or the swelling agent is dispersed in water, and then the polymer is dispersed in the water. Disperse the fine particles. In this case, a part of the swelling agent may be mixed with the polymer fine particles. In order to stably disperse the polymer fine particles and the swelling agent in water, the same surfactant as used in the precipitation polymerization method and / or a water-soluble polymer such as polyvinyl alcohol, carboxymethylcellulose, sodium alginate, and sodium polyacrylate are usually used. Use molecules. When the polymer fine particles and the swelling agent are dispersed in water as described above, the polymer fine particles are swollen by the swelling agent, and as a result, an aqueous dispersion of a swelled body of the polymer fine particles is prepared. Then, the above-mentioned comonomer is dispersed in the aqueous dispersion, and the swollen body absorbs the comonomer and performs polymerization. The initiator used for the polymerization of the comonomer may be the same as that used in the precipitation polymerization method, and the initiator is usually dissolved in the swelling agent and / or the comonomer.
The polymerization is usually performed at a temperature of about 60 to 80 ° C., preferably in an inert gas atmosphere. In this way, spherical polymer fine particles having a uniform particle size can be obtained. The obtained polymer fine particles are collected by filtration, centrifugation, or the like, and, if desired, washed with water and dried. Thus, the spherical polymer powder of the present invention is obtained, and the diameter of the particles of the spherical polymer powder is affected by the diameter of the polymer fine particles serving as seeds, but is usually 1 to 10 μm. Things.

(Hydrolysis) Since the spherical polymer fine particles obtained by the above method contain a hydrolyzable silyl group, when hydrolyzed with an acid or alkali, the silyl group becomes a silanol group and the silanol groups react with each other. To form silane crosslinks. Acids used in this case include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid, and organic acids such as formic acid, oxalic acid, and acetic acid, and alkalis include caustic potash, caustic soda, ammonia, and amine. To perform the hydrolysis, the obtained spherical polymer powder is immersed in the aqueous solution of the acid or alkali. The concentration of the aqueous acid or alkali solution used at this time depends on the strength of the selected acid or alkali, but generally a low concentration of 5% by weight or less is sufficient. And although hydrolysis is carried out at room temperature,
If desired, it may be heated to about 80 ° C. The time required for the hydrolysis is, of course, affected by the strength and concentration of the acid or alkali, and the hydrolysis temperature,
Usually, it takes about 2 to 3 hours.

[Action] By copolymerizing the vinyl monomer having a hydrolyzable silyl group with another vinyl monomer copolymerizable with the vinyl monomer, the hydrolyzable Silyl groups are incorporated into the copolymer. The hydrolyzable silyl groups are hydrolyzed to generate silanol groups, and the silanol groups react with each other to form silane crosslinks. Further, a comonomer of the vinyl monomer having a hydrolyzable silyl group and another vinyl monomer copolymerizable with the vinyl monomer is soluble and also in the comonomer. In a solvent where the copolymer is insoluble,
The comonomer precipitates in the solvent as spherical particles having a uniform particle size. At this time, the hydrolyzable silyl group has a favorable effect on the sphericity of the particles and the uniformity of the particle diameter. Further, when the comonomer is dispersed in the polymer powder aqueous dispersion swollen by the swelling agent, the comonomer is absorbed in the swollen body and polymerized. In this way, the comonomer is polymerized using the polymer powder as a seed to obtain spherical polymer particles having a uniform particle size. Even in this case, the hydrolyzable silyl group has a favorable effect on the sphericity of the particles and the uniformity of the particle diameter.

Example 1 Example 1 (Production of Copolymer A) A solution prepared by dissolving 4 parts by weight of polyvinylpyrrolidone in 160 parts by weight of ethanol in a reactor equipped with a stirrer, a condenser, a thermometer, and a gas inlet tube. And 5 parts by weight of γ-methacryloxypropyltrimethoxysilane as a vinyl monomer having a hydrolyzable silyl group and 30 parts by weight of styrene are mixed with azobisisobutyronitrile 0.1%. Add a solution of 5 parts by weight,
The mixture is heated to 70 ° C. with stirring at a rotational speed of 350 rpm and reacted for 24 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, 50 g of 5% by weight aqueous ammonia was added, and the mixture was stirred at room temperature for 2 hours to carry out hydrolysis and cross-linking reaction. The obtained cross-linked polymer particles were collected by centrifugation and washed with water. Thereafter, it is dried by heating at 60 ° C. for 5 hours. The obtained crosslinked polymer particles were arbitrarily selected from 100 particles by a scanning electron microscope photograph, and the particle diameter was measured.
It has a particle size of μm. After the fine particles were immersed in tetrahydrofuran and chloroform and ultrasonically stirred, the state of the particles was observed again by a scanning electron microscope, but no change was found in the shape and the particle size.

Example 2 (Production of Copolymer B) In a beaker, 0.3 part by weight of sodium lauryl sulfate was added to water 1
Then, 2.5 parts by weight of benzoyl peroxide was added to 12.5 parts by weight of 1,2-dichloroethane 12.5 parts by weight.
1 part by weight and 17.5 parts by weight of 1-chlorododecane dissolved in a mixed swelling agent were added and stirred by a homogenizer to disperse the swelling agent so that the diameter of the droplet was 0.5 μm or less. . In the same reactor as in Example 1, an aqueous dispersion of polystyrene having a particle size of 0.63 μm (solid concentration 1
0% by weight), 100 parts by weight of acetone, 20 parts by weight of acetone was further added, and the aqueous dispersion of the above-mentioned swelling agent was poured into the mixture.
The polystyrene particles are swelled with the swelling agent by gentle stirring at 5 ° C. for 24 hours. Then, a co-monomer obtained by mixing 200 parts by weight of methyl methacrylate, 440 parts by weight of styrene, and 64 parts by weight of vinyltrimethoxysilane as a vinyl monomer having a hydrolyzable silyl group was mixed with 0.7 part by weight of sodium lauryl sulfate in water. The comonomer is poured into the reactor together with the solution dissolved in 4000 parts by weight and stirred at 40 rpm at 400 rpm for 2 hours to absorb the comonomer into the swollen body of the polystyrene particles. After raising the temperature to 65 ° C. and reacting for 8 hours, the polymer particles obtained by cooling to room temperature were collected by filtration, washed with water, immersed in a 0.5% by weight aqueous sodium hydroxide solution for 4 hours at room temperature. The crosslinked polymer particles obtained by being left to undergo hydrolysis and crosslinking reaction are filtered off, washed with water and dried at 75 ° C. for 3 hours. The obtained crosslinked polymer fine particles were spherical, had a uniform particle size of 2.4 ± 0.3 μm, and did not change in shape or particle size due to immersion in tetrahydrofuran and chloroform.

[0022]

As described above, the polymer fine particles of the present invention have a perfect spherical shape and a uniform particle size, and since they are cross-linked, they have good heat resistance, solvent resistance, etc., and can be used as a filler for paints and cosmetics. It is extremely useful as a filler for plastics and a filler for plastics.

Claims (1)

[Claims] 1. A copolymer of a vinyl monomer having a hydrolyzable silyl group alone or in combination of two or more with another vinyl monomer copolymerizable with the vinyl monomer. Crosslinked polymer microparticles characterized by hydrolyzing silyl groups contained in polymer microparticles to form crosslinks