JP2002308992A - Dispersion of crosslinked microparticle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a dispersion of crosslinked microparticles which, when added to a resin, can be uniformly dispersed in the form of primary particles in the resin. SOLUTION: This dispersion is the one prepared by polymerizing a non- crosslinking monomer (A) with a crosslinking monomer (B) in a solvent (C) in the presence of a polymerization initiator, and then replacing the solvent (C) contained in the dispersion with an organic solvent (E) which has a boiling point higher than that of the solvent (C) and does not dissolve the crosslinked microparticles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a crosslinked fine particle dispersion. The crosslinked fine particle dispersion can be easily mixed with any resin soluble in the dispersion solvent, and the crosslinked fine particles are not aggregated, and variously dispersed in the resin in the form of primary particles in the resin. Functions can be provided.

[0002]

2. Description of the Related Art Conventionally, crosslinked acrylic fine particles have been
It is added to resins such as paints, adhesives, adhesives, and films, and is used to impart matting properties, lubricity, blocking resistance, optical properties, improve mechanical strength, and impart functions such as spacers. . Above all, in the field where the performance is controlled by the particle size, the absolute condition is to use monodisperse fine particles, and it is difficult to produce monodisperse fine particles in the particle size range of 0.5 to 3 μm, which is the most required. Tremendous cost and effort. In particular, in recent years, monodispersed crosslinked fine particles having a particle diameter of about 1 μm have been increasingly important due to thinning of a coating film or a film.

As methods for obtaining crosslinked acrylic fine particles of about 1 μm, seed emulsion polymerization, two-stage swelling polymerization, and dispersion polymerization are mentioned. Seed emulsion polymerization and two-step swelling polymerization are methods for swelling seed particles with a monomer to increase the particle size, and require many steps to obtain particles having a desired particle size.

[0004] On the other hand, dispersion polymerization is a technique for synthesizing fine particles having a sharp particle size distribution in one step, and fine particles having a desired particle size can be obtained very efficiently. Conventionally, when fine particles are produced by a dispersion polymerization method, the use of a dispersion stabilizer has been essential. However, in the conventional synthesis method,
The type and amount of the dispersion stabilizer are limited, and when used as an additive, depending on the resin, it may not be possible to use the dispersion stabilizer in terms of compatibility. Also, in some cases, the dispersion stabilizer has heat resistance,
Since it has an adverse effect such as water resistance, it is necessary to remove the dispersion stabilizer before adding it to the resin. From these points,
In order to remove the dispersion stabilizer, a method of drying the fine particles and then removing the dispersion stabilizer by washing is used. But,
When the fine particles are agglomerated during drying and secondary particles having a larger particle size are added to the resin, it is very difficult to disperse the particles in the state of primary particles, and the removal of the large particle size by classification is required. A process becomes necessary.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dispersion of crosslinked fine particles which can be uniformly dispersed in the resin in the state of primary particles when the crosslinked fine particles are added to the resin. And Another object of the present invention is to provide a method for producing a crosslinked fine particle dispersion which does not include a drying / washing step for removing a dispersion stabilizer or the like.

[0006]

That is, the present invention relates to a method for polymerizing a non-crosslinkable monomer (A) and a crosslinkable monomer (B) in a solvent (C) using a polymerization initiator to obtain a crosslinked monomer. The present invention relates to a crosslinked fine particle dispersion obtained by replacing the fine particle dispersion (D) with an organic solvent (E) having a higher boiling point than the solvent (C) and not dissolving the crosslinked fine particles.

The present invention also relates to a crosslinkable monomer (B)
Is a polyfunctional monomer having a polymerizable unsaturated carboxylic acid residue and a reactive functional group other than the polymerizable unsaturated carboxylic acid residue.

[0008] The present invention also relates to the crosslinked fine particle dispersion described above, wherein the average particle diameter of the crosslinked fine particles is 0.5 to 3 µm.

Further, the present invention relates to the above-mentioned crosslinked fine particle dispersion, wherein the decomposition temperature of the crosslinked fine particles is 240 ° C. or more and the gel fraction is 95% or more.

[0010] Further, the present invention provides a method for preparing a dispersion
The present invention relates to the above crosslinked fine particle dispersion, wherein the initiator is represented by the following formula (1) or (2).

Equation (1)

[0012]

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[Wherein R ¹ and R ² each independently represent a hydrogen atom, an alkyl group or an aromatic substituent. ] Equation (2)

[0014]

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[Wherein, R ³ and R ⁴ each independently represent an alkylene group or a divalent aromatic substituent. Further, the present invention relates to a method for synthesizing the crosslinked fine particle dispersion, wherein the solvent (C) is a mixed solvent of water and alcohol.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The crosslinked fine particles referred to in the present invention are:
The fine particles having the inside of the particles crosslinked at the end of the synthesis. The fine particles having excellent solvent resistance and heat resistance can be obtained by the crosslinking inside the particles.

The crosslinkable monomer (B) of the present invention is a difunctional or trifunctional or higher polyfunctional monomer having a functional group for imparting crosslinkability, and functions as a crosslinking agent. At least one of the functional groups of the crosslinkable monomer (B) is necessary to cause copolymerization with the non-crosslinkable monomer (A), and the remaining functional groups are used as functional groups for imparting crosslinkability. Function.

Examples of the functional group for providing the crosslinking property of the crosslinking monomer (B) include a vinyl group, a hydroxyl group, an epoxy group, a carboxyl group, and an alkoxysilyl group. Examples include, but are not limited to, crosslinking by an addition reaction between an epoxy group and a carboxyl group or a hydroxyl group, and crosslinking by hydrolysis and condensation of an alkoxysilyl group.

Examples of the crosslinkable monomer (B) include allyl (meth) acrylate, 1-methylallyl (meth) acrylate, 2-methylallyl (meth) acrylate, 1-butenyl (meth) acrylate, and (meth) acrylate. 2-butenyl acrylate,
3-butenyl (meth) acrylate, 1, (meth) acrylic acid 1,
3-methyl-3-butenyl, 2-chloroallyl (meth) acrylate, 3-chloroallyl (meth) acrylate, o-allylphenyl (meth) acrylate, 2- (allyloxy) ethyl (meth) acrylate, (meth) ) Allyl lactyl acrylate, citronellyl (meth) acrylate, geranyl (meth) acrylate, rhinyl (meth) acrylate, (meth)
Unsaturated group-containing (meth) acrylates such as cinnamyl acrylate, diallyl maleate, diallyl itaconic acid, vinyl (meth) acrylate, vinyl crotonate, vinyl oleate, and vinyl linolenate; glycidyl (meth) acrylate Heterocyclic-containing (meth) acrylates such as (3,4-epoxycyclohexyl) methyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate; 2-hydroxyethyl (meth) acrylate;
Hydroxy (alkoxy) -containing (meth) acrylates such as hydroxypropyl (meth) acrylate, 2-methoxyethyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate; ethylene glycol di (meth) acrylate Triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,1,1-trishydroxy diacrylate Methylethane,
Polyfunctional (meth) acrylates such as 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethylpropane triacrylate;
3-methacryloxypropyltrimethoxysilane, 3-
Methacryloxypropyltriethoxysilane, 3-methacryloxypropyltriisopropoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2- Alkoxysilyl group-containing monomers such as methoxyethoxy) silane; divinyls such as divinylbenzene and divinyl adipate; diallyl isophthalate;
Diallyls such as diallyl phthalate and diallyl maleate; unsaturated carboxylic acids such as (meth) acrylic acid and itaconic acid; unsaturated carboxylic anhydrides such as itaconic anhydride and maleic anhydride; and the like. It is not particularly limited to these.

Among them, crosslinking by radical polymerization of vinyl groups occurring during the growth of the polymer is preferable, and more preferably, aggregation and polydispersion of particles during polymerization are unlikely to occur, and the resulting particles have good heat resistance. Monomers having different reactivity of each functional group are preferred. Specifically, (meta)
A compound having a polymerizable unsaturated carboxylic acid residue such as an acrylic acid residue, a crotonic acid residue, a maleic acid residue, an itaconic acid residue, and a reactive functional group other than the polymerizable unsaturated carboxylic acid residue Is preferred. The reactive functional groups other than the polymerizable unsaturated carboxylic acid residues include reactive functional groups such as a vinyl group, a hydroxyl group, an epoxy group, a carboxyl group, and an alkoxysilyl group.

For example, as the vinyl group, an ethenyl group,
1-propenyl group, allyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, carbon number of 1-1 such as 2-pentenyl group
An unsaturated group-containing alkyl group such as a styryl group or a cinnamyl group; a heterocyclic group-containing acrylic group such as a tetrahydrofurfuryl group; a hydroxy group, a hydroxy group, a hydroxymethylene group, or a hydroxy group; A hydroxyalkylene group such as an ethylene group; an epoxy group as a glycidyl group; an alkoxysilyl group as
Examples include an alkoxysilyl group such as a trimethoxysilyl group and a triethoxysilyl group, but are not particularly limited thereto.

Examples of such a crosslinkable acrylic monomer (B) include allyl (meth) acrylate, 1-methylallyl (meth) acrylate, 2-methylallyl (meth) acrylate, and 1-methyl (meth) acrylate. Butenyl, 2-butenyl (meth) acrylate, 3-butenyl (meth) acrylate, 1,3-methyl-3-butenyl (meth) acrylate, 2-chloroallyl (meth) acrylate, (meth) acrylic acid 3 -Chlorallyl, o-allylphenyl (meth) acrylate, (meth)
2- (allyloxy) ethyl acrylate, allyl lactyl (meth) acrylate, citronellyl (meth) acrylate, geranyl (meth) acrylate, rosinyl (meth) acrylate, cinnamyl (meth) acrylate, diallyl maleate, diallyl itacon Acid, vinyl (meth) acrylate, vinyl crotonate, vinyl oleate, vinyl linoleate and other unsaturated group-containing (meth) acrylates; glycidyl (meth) acrylate, (meth) acrylic acid (3,4) (Epoxycyclohexyl) methyl, heterocyclic-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate; (meth) acrylic acid 2
Hydroxy (alkoxy) -containing (meth) acrylates such as -hydroxyethyl, hydroxypropyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate; 3-methacryloxy Alkoxysilyl group-containing monomers such as propyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltriisopropoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane Unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, crotonic acid and the like, but not particularly limited thereto. These can be used in combination of two or more. Also,
It is preferable that the amount of the monomer (B) in all the monomers is 5 to 20% by weight.

The non-crosslinkable monomer (A) is a monomer having no functional group for providing the above-mentioned crosslinkability, and (meth)
Methyl acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, N-amyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate, Acrylates such as dodecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobonyl (meth) acrylate, and phenyl (meth) acrylate; styrene;
Vinyltoluene, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-
Styrene-based monomers such as methylstyrene, 1-butylstyrene, and chlorostyrene are exemplified, but not particularly limited thereto. These may be used in combination of two or more.

Above all, it is desirable to use a hydrophobic non-crosslinkable monomer (A) in combination, since fine particles having good monodispersity can be obtained. The hydrophobic non-crosslinkable monomer (A) represents a monomer having a solubility in water at 20 ° C. of 2.0 × 10 ⁻³ g / cm ³ or less, for example, cyclohexyl (meth) acrylate,
Benzyl (meth) acrylate, isobonyl (meth) acrylate, phenyl (meth) acrylate and the like can be mentioned.

The amount of the hydrophobic non-crosslinkable monomer (A) is preferably 0 to 50% by weight of the whole non-crosslinkable monomer (A).

In the present invention, a dispersion stabilizer and a surfactant are not particularly used. However, when a dispersion stabilizer and a surfactant are necessary for imparting a function, they may be added. At this time, since the addition of the dispersion stabilizer and the surfactant does not affect the synthesis mechanism of the monodispersed crosslinked particles, the type and amount can be arbitrarily changed.

The dispersion stabilizer and the surfactant include:
Dispersion stabilizers such as polyvinyl alcohol and polyvinylpyrrolidone that improve compatibility with polyvinyl chloride and styrene acrylic copolymer, and polyoxyethylene polyoxypropylene block copolymers that improve compatibility with polypropylene (Epan, Daiichi Kogyo Seiyaku) Nonionic surfactants such as polyether-modified silicone (Silwet, manufactured by Nippon Unicar), cationic surfactants such as quaternary ammonium salts (Cotamine, manufactured by Kao) used for antistatic effect, alkyldimethyl Examples include amphoteric surfactants such as betaine aminoacetate (Amogen, manufactured by Daiichi Kogyo Seiyaku), but are not particularly limited thereto. The addition of the dispersion stabilizer and the surfactant may be performed during or after the polymerization.

The solvent (C) used in the present invention is selected from those in which the monomer is homogeneously dissolved and the crosslinked fine particles, which are polymers obtained by polymerizing the monomer, are insoluble. Such solvents include methanol, ethanol, n-propanol, isopropanol, n-
Alcohols such as butanol and t-butanol; diethyl ether, isopropyl ether, butyl ether,
Ethers such as methyl cellosolve and tetrahydrofuran; acetone, methyl ethyl ketone, diethyl ketone,
And the like. Ketones, etc .; a mixed solvent of the above-mentioned solvent and water; and the like, and particularly, methanol, ethanol, or a mixed solvent thereof with water is desirable. Further, these solvents can be used as a mixture of two or more kinds. As for the total solvent, the total amount of the monomers is preferably 10 to 30% by weight based on the total solvent. The amount of water in the total solvent is preferably 0 to 70% by weight.

As the initiator, a cationic water-soluble azo polymerization initiator is used. Basically, any compound can be used as long as it can make the terminal of the polymer chain cationic with an initiator. For example, a compound represented by the formula (1) or a compound represented by the formula (2)
The compound represented by these is mentioned.

R ¹ and R ^{2 in} the formula (1) are a hydrogen atom; an alkyl group such as a methyl group, an ethyl group and a propyl group; an alkyl hydroxide group such as a hydroxymethyl group, a hydroxyethyl group and a hydroxypropyl group; And aromatic groups such as benzyl and benzyl groups; halogenated aromatic groups such as chlorophenyl and chlorobenzyl groups; and hydroxylated aromatic groups such as hydroxyphenyl and hydroxybenzyl, but are particularly limited to these. is not. As an example of equation (1),
2,2'-azobis [2- (phenylamidino) propane] dihydrochloride (VA-545, manufactured by Wako Pure Chemical Industries), 2,2'-azobis {2- [N- (4-chlorophenyl) amidino] propane} dihydro Chloride (VA-546, manufactured by Wako Pure Chemical), 2,2'-azobis {2- [N- (4-droxyphenyl) amidino] propane} dihydrochloride (VA-548, manufactured by Wako Pure Chemical), 2, 2'-azobis [2- (N-benzylamidino) propane] dihydrochloride (VA-552, manufactured by Wako Pure Chemical Industries), 2,2'-azobis [2- (N-allylamidino) propane] dihydrochloride (VA- 553, manufactured by Wako Pure Chemical Industries), 2,2'-azobis (2-amidinopropane) dihydrochloride (V-50, manufactured by Wako Pure Chemical Industries), 2,2'-azobis-2- [N- (4-hydroxyethyl ) Amidino] propane dihydrochloride (VA-558, manufactured by Wako Pure Chemical Industries) and the like.

R ³ and R ^{4 in} the formula (2) represent an alkylene group such as a methylene group, an ethylene group or a propylene group; an alkylene hydroxide group such as a hydroxymethylene group or a hydroxyethylene group; a phenylene group or a biphenylene group. 2
Examples include, but are not particularly limited to, valent aromatic substituents.

As an example of the formula (2), 2,2-azobis [2-
(5-methyl-2-imidazolin-2-yl) propane] dihydrochloride (VA-041, manufactured by Wako Pure Chemical Industries), 2,2-azobis [2-
(2-imidazolin-2-yl) propane] dihydrochloride (VA-044, manufactured by Wako Pure Chemical Industries), 2,2-azobis [2- (4,5,6,7-
Tetrahydro-1H-1,3-diazepin-2-yl) propane] dihydrochloride (VA-054, manufactured by Wako Pure Chemical Industries), 2,2-azobis
[2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride (VA-058, manufactured by Wako Pure Chemical Industries), 2,2-azobis [2- (5-hydroxy-3,4 , 5,6-Tetrahydropyrimidin-2-yl) propane] dihydrochloride (VA-059, manufactured by Wako Pure Chemical Industries), 2,2-azobis2-2- [1- (2-hydroxyethyl) -2-imidazoline-2 -Yl] propane dihydrochloride (VA-060, manufactured by Wako Pure Chemical), 2,2-azobis [2- (2-imidazolin-2-yl) propane] (VA-061, manufactured by Wako Pure Chemical) and the like Can be The radical initiator is preferably 0.10 to 0.30% by weight based on the total amount of the monomers.

In the synthesis of the crosslinked fine particle dispersion (D) of the present invention, for example, the non-crosslinkable monomer (A) and the crosslinkable monomer (B) are uniformly dissolved in the solvent (C),
After removing dissolved oxygen and heating to 60 ° C., a solution obtained by dissolving the initiator in ion-exchanged water is added, and the mixture is heated and stirred for 3 to 10 hours.

When the conversion after polymerization is not sufficient, an initiator is added after the polymerization is completed in an amount of 0.1 to 2% by weight based on the total amount of the monomers. As the initiator to be added, any ordinary oil-soluble radical polymerization initiator can be used without any problem. For example, 2,2-azobis (4-methoxy-2,4-dimethylvaleronitrile) (V
-70, made by Wako Pure Chemical), 2,2'-azobis (2,4-dimethylvaleronitrile) (V-65, made by Wako Pure Chemical) 2,2'-azobisisobutyronitrile (V-60, Azonitrile compounds such as Wako Pure Chemical Industries, Ltd., 2,2'-azobis (2-methylbutyronitrile) (V-59, manufactured by Wako Pure Chemical Industries), octanoyl peroxide (Perloyl O, Nippon Oil & Fats), lauroyl par Oxide (Perloyl L, Nippon Yushi), Stearoyl peroxide (Paloyl S, Nippon Yushi), succinic acid peroxide (Paloyl SA, Nippon Yushi), benzoyl peroxide (Niper BW, Nippon Yushi), Isobutylene Luper oxide (Perloyl IB, manufactured by NOF Corporation),
Diacyl peroxides such as 2,4-dichlorobenzoyl peroxide (Niper CS, manufactured by NOF), 3,5,5-trimethylhexanoyl peroxide (PARLOYL 355, manufactured by NOF), di-n-propylperoxy Dicarbonate (Perloyl NPP-50M, manufactured by NOF), Diisopropylperoxydicarbonate (Perloyl IPP-50, manufactured by NOF), Bis (4-t-butylcyclohexyl) peroxydicarbonate (Perloyl TCP, manufactured by NOF) , Di-
2-ethoxyethyl peroxydicarbonate (Perloyl EEP, manufactured by NOF), di-2-ethoxyhexylperoxydicarbonate (Perloyl OPP, manufactured by NOF), di-
Peroxydicarbonates such as 2-methoxybutyl peroxydicarbonate (Perloyl MBP, manufactured by NOF) and di (3-methyl-3-methoxybutyl) peroxydicarbonate (Perloyl SOP, manufactured by NOF); t- Butyl hydroperoxide (Perbutyl H-69, manufactured by NOF Corporation),
Hydroperoxides such as 1,1,3,3-tetramethylbutyl hydroperoxide (Perocta H, manufactured by NOF), di-t-butyl peroxide (Perbutyl D, manufactured by NOF), 2,5- Dialkyl peroxides such as dimethyl-2,5-bis (t-butylperoxy) hexane (Perhexa 25B, manufactured by Nippon Oil & Fats), α, α'-bis (neodecanoylperoxy) diisopropylbenzene (Diper ND,
Nippon Yushi), cumyl peroxy neodecanoate (Park Mill ND, Nippon Yushi), 1,1,3,3-tetramethylbutylperoxy neodecanoate (Perocta ND, Nippon Yushi), 1-cyclohexyl 1-methylethyl peroxy neodecanoate (Percyclo ND, manufactured by NOF Corporation), t-
Hexyl peroxy neodecanoate (perhexyl N
D, Nippon Oil & Fats), t-butyl peroxy neodecanoate (Perbutyl ND, Nippon Oil & Fats), t-hexyl peroxypivalate (Perhexyl PV, Nippon Oil & Fats), t-
Butyl peroxypivalate (Perbutyl PV, manufactured by NOF), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (PeroctaO, manufactured by NOF) 2,5-dimethyl-2 , 5-bis (2-ethylhexanoyl peroxy)
Hexane (Perhexa 250, manufactured by NOF Corporation), 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate (Percyclo O, manufactured by NOF Corporation), t-hexylperoxy 2-ethylhexanoate (Perhexyl O) T-butyl peroxy 2-ethylhexanoate (Perbutyl O, Nippon Yushi), t-butyl peroxyisobutyrate (Perbutyl IB, Nippon Yushi), t-hexyl peroxyisopropyl mono Organic peroxides such as peroxyesters such as carbonate (Perhexyl I, manufactured by Nippon Yushi) and t-butyl peroxymaleic acid (Perbutyl MA, manufactured by Nippon Oil & Fat), and the like, but are not particularly limited thereto. Not something.

The crosslinked fine particle dispersion (D) of the present invention is obtained as a monodisperse fine particle dispersion having excellent heat resistance and solvent resistance. Further, by selecting the composition of the monomer (A) and the amount of water, particles having a desired particle size in the range of 0.1 to 3.0 μm can be obtained. In the present invention, the term "heat resistance" means that the decomposition temperature of the crosslinked fine particles is at least 240 ° C, and the term "solvent resistance" means that the gel fraction in methyl ethyl ketone is at least 95%. Decomposition temperature and gel fraction are as follows: Crosslinked fine particle dispersion after polymerization (D)
After removing the solvent by centrifugation, vacuum drying is performed at 80 ° C. for 12 hours, and measurement is performed using the obtained crosslinked fine particles. The decomposition temperature is measured using a commercially available thermogravimetric (TG) device under a nitrogen atmosphere at a heating rate of 10 ° C./min. In the present invention, the weight loss at the time of raising the temperature occurs in one step, and the temperature at which the peak of the differential thermogravimetric (DTG) curve becomes the maximum is called the decomposition temperature. Also,
The gel fraction referred to in the present invention refers to the weight of the pre-crosslinked fine particles dispersed in methyl ethyl ketone, left at 23 ° C. and 65% for 24 hours, and then the solvent is removed by centrifugation, followed by vacuum drying at 80 ° C. for 6 hours. Say the rate of change.

The decomposition temperature of the crosslinked fine particles of the present invention is 240 ° C.
The gel fraction in methyl ethyl ketone was 95%
That is all. In the present invention, a fine particle dispersion having a particle size distribution having a coefficient of variation of 30% or less is referred to as a monodisperse fine particle dispersion.
The coefficient of variation can be determined by, for example, a commercially available laser diffraction light scattering particle sizer. The coefficient of variation is expressed as a percentage of the standard deviation divided by the mean. The dispersion coefficient of the crosslinked fine particle dispersion of the present invention is as uniform as 5 to 30%.

The solvent (E) used in the present invention is selected from organic solvents having a higher boiling point than the solvent (C) and not dissolving the crosslinked fine particles. As the solvent (E), any organic solvent such as petroleum hydrocarbons, plant hydrocarbons, aromatic hydrocarbons, alcohols, ketones, ethers and esters can be used alone or in combination. . The solvent (E) is preferably compatible with the solvent (C).

When methanol or ethanol or a mixed solvent thereof is used as the solvent (C) for polymerizing the monodispersed crosslinked fine particles, the solvent (E) may be, for example, isobutyl alcohol, s -Butyl alcohol, n-amyl alcohol, n-hexyl alcohol, 2-methylpentan-1-ol, s-hexyl alcohol, 2-ethylbutyl alcohol, s-heptyl alcohol, heptan-3-ol, 2-ethylhexyl alcohol, 2,6-dimethyl-4-heptanol,
Methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, phenylmethylcarbinol, diethyl ketone, methyl isobutyl ketone, methyl-n-amyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, 2,4-pentanedione, n-butyl ether, dioxane, dimethyl dioxane, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono- n-hexyl ether, ethylene glycol monophenyl ether, Tylene glycol mono-2-ethylhexyl ether, ethylene glycol dibutyl ether, ethylene glycol monoallyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol mono Butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol dibutyl ether, diethylene glycol mono-n-hexyl ether, diethylene glycol mono-2-ethylhexyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether Triethylene glycol dimethyl ether, ethoxy triglycol, tetraethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol methyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, Propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, propylene glycol monophenyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, lactic acid-n-
Butyl and the like.

In the present invention, the substitution of the solvent means removing the solvent (C) until the proportion of the solvent (E) in the total solvent becomes 90% by weight or more. A method of adding the solvent (E) to the dispersion liquid (D) and removing the solvent (C) by a stripping method, etc. Since the crosslinked fine particles of the present invention are excellent in heat resistance and solvent resistance, the temperature can be raised to 100 ° C. during stripping. When this method is used, since a drying step is not performed, a crosslinked fine particle dispersion is obtained without being aggregated with each other and in a state of being dispersed by primary particles. In this step, the concentration of the crosslinked fine particle dispersion can be arbitrarily changed from 1 to 50% by weight. If it is higher than 50% by weight, the distance between the particles becomes small, and a stable dispersion state cannot be maintained, and aggregation of the particles occurs.

Further, as a feature of the present invention, the crosslinked fine particle dispersion (D) becomes fine particles having a narrow particle size distribution without using a dispersion stabilizer and a surfactant, and is replaced with a solvent (E). Fine particles can be uniformly dispersed in a resin in a state of primary particles without a drying step.

[0041]

Next, the present invention will be described in detail with reference to examples. In the examples, parts and% are all based on weight unless otherwise specified. Example 1 89.6 parts of methanol, 9.0 parts of methyl methacrylate (manufactured by Wako Pure Chemical), benzyl methacrylate (manufactured by Wako Pure Chemical) were placed in a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
0.5 part and 0.5 part of allyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) were charged, and dissolved oxygen was removed by flowing nitrogen gas. 60 reactors
After heating to 50 ° C, a solution prepared by dissolving 0.025 parts of V-50 (manufactured by Wako Pure Chemical Industries) in 0.5 parts of ion-exchanged water was added, and the mixture was heated and stirred for 8 hours.
Benzoyl peroxide (Niper BW, manufactured by NOF Corporation)
Was added, and the mixture was further heated and stirred for 2 hours to obtain a solid content of 10.
%, A particle diameter of 2.07 μm, and a variation coefficient of 24.0%. Subsequently, 30.0 parts of propylene glycol monomethyl ether acetate was added, and a water pipe was attached.
A total of 90.1 parts of methanol and water was distilled off at 70 to 90 ° C. to obtain a solvent-substituted monodispersed crosslinked fine particle dispersion having a solid content of 25%. Examples 2 to 5 The amounts of methyl methacrylate, benzyl methacrylate and allyl methacrylate charged in advance to the reaction vessel are shown.
Polymerization was carried out in the same manner as in Example 1 except that the amount was charged in the amount shown in 1, to obtain a monodispersed crosslinked fine particle dispersion. Examples 6 to 12 In the same manner as in Example 1 except that methanol previously charged to the reaction vessel was changed to a mixed solvent of methanol and water or ethanol and water, and methanol and water or ethanol and water were charged at a mixing ratio shown in Table 1. Polymerization was performed to obtain a monodispersed crosslinked fine particle dispersion. Example 13 The same reactor as in Example 1 was charged with 84.5 parts of methanol, 13.5 parts of methyl methacrylate (manufactured by Wako Pure Chemical), 0.75 parts of benzyl methacrylate (manufactured by Wako Pure Chemical), and 0.75 part of allyl methacrylate (manufactured by Wako Pure Chemical). Then, nitrogen gas was flowed to remove dissolved oxygen. After heating the reactor to 60 ° C., a solution prepared by dissolving 0.025 part of V-50 (manufactured by Wako Pure Chemical Industries, Ltd.) in 0.5 part of ion-exchanged water was added, and the mixture was heated and stirred for 8 hours. Then, benzoyl peroxide (Niper BW, manufactured by NOF Corporation) ) Is added and 0.12 parts are added.
The mixture was heated and stirred for a period of time to obtain a monodispersed crosslinked fine particle dispersion having a solid content of 15%, a particle size of 2.20 μm, and a variation coefficient of 10.2%. Subsequently, 60.0 parts of propylene glycol monomethyl ether acetate was added, and a water separation tube was attached. A total of 85.0 parts of methanol and water was distilled off at 70 to 90 ° C., and the solvent-substituted solid content 25%
Was obtained. Examples 14 to 16 Change the methanol to be charged to the reaction vessel in advance to a mixed solvent of methanol and water, polymerized in the same manner as in Example 13 except that methanol and water were charged at the mixing ratio shown in Table 1, and monodispersed crosslinked fine particles. A dispersion was obtained. Example 17 The same reactor as in Example 1 was charged with 79.5 parts of methanol, 18 parts of methyl methacrylate (manufactured by Wako Pure Chemical), 1.0 part of benzyl methacrylate (manufactured by Wako Pure Chemical), and 1.0 part of allyl methacrylate (manufactured by Wako Pure Chemical). Then, nitrogen gas was flowed to remove dissolved oxygen. After heating the reactor to 60 ° C., a solution prepared by dissolving 0.014 part of V-50 (manufactured by Wako Pure Chemical Industries, Ltd.) in 0.5 part of ion-exchanged water was added, and the mixture was heated and stirred for 8 hours. Then, benzoyl peroxide (Niper BW, manufactured by NOF Corporation) ) Was added to 0.05 part, and 2
The mixture was heated and stirred for an hour to obtain a monodispersed crosslinked fine particle dispersion having a solid content of 20%, a particle size of 2.52 μm, and a variation coefficient of 15.6%. Subsequently, 80.0 parts of propylene glycol monomethyl ether acetate was added, and a water pipe was attached. At 70 to 90 ° C., 80.0 parts of methanol and water were distilled off, and the solvent-substituted solid content was 25%.
Was obtained. Examples 18 to 19 Change the methanol charged to the reaction vessel in advance to a mixed solvent of methanol and water, polymerized in the same manner as in Example 17 except that methanol and water were charged at the mixing ratio shown in Table 1, and monodispersed crosslinked fine particles. A dispersion was obtained. Example 20 In a reactor equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, 84.5 parts of methanol, 14.8 parts of methyl methacrylate (manufactured by Wako Pure Chemical), and benzyl methacrylate (manufactured by Wako Pure Chemical)
0.75 parts and 0.45 part of vinyl methacrylate (manufactured by Tokyo Chemical Industry) were charged, and nitrogen gas was flown to remove dissolved oxygen. 60 reactors
After heating to 50 ° C, a solution prepared by dissolving 0.025 parts of V-50 (manufactured by Wako Pure Chemical Industries) in 0.5 parts of ion-exchanged water was added, and the mixture was heated and stirred for 8 hours.
Benzoyl peroxide (Niper BW, manufactured by NOF Corporation)
Was added, and the mixture was further heated and stirred for 2 hours to obtain a solid content of 1
A monodispersed crosslinked fine particle dispersion having a particle size of 5%, a particle size of 1.87 μm, and a variation coefficient of 21.6% was obtained. Subsequently, 30.0 parts of propylene glycol monomethyl ether acetate was added, and a water pipe was attached. At 70 to 90 ° C., 85.0 parts of methanol and water were distilled off, and a solvent-replaced monodispersed crosslinked fine particle dispersion having a solid content of 25% was added. Obtained. Examples 21 to 23 Change the methanol charged to the reaction vessel in advance to a mixed solvent of methanol and water, polymerized in the same manner as in Example 22 except that methanol and water were charged at a mixing ratio shown in Table 1, and monodispersed crosslinked fine particles. A dispersion was obtained. Example 24 84.5 parts of methanol, 13.8 parts of methyl methacrylate (manufactured by Wako Pure Chemical), 0.75 parts of benzyl methacrylate (manufactured by Wako Pure Chemical), and 0.45 part of vinyl crotonate (manufactured by Wako Pure Chemical) were placed in the same reactor as in Example 1. Charged, nitrogen gas was flowed to remove dissolved oxygen. After heating the reactor to 60 ° C, V-50 (Wako Pure Chemical Industries)
Dissolve 0.025 parts in 0.5 parts of ion-exchanged water and add
After heating and stirring for 0.1 hour, 0.15 parts of benzoyl peroxide (Niper BW, manufactured by NOF Corporation) was added, and the mixture was further heated and stirred for 2 hours, and the solid content was 15%, the particle size was 2.11 μm, and the variation coefficient was 1
A 3.4% monodispersed crosslinked fine particle dispersion was obtained. Subsequently, propylene glycol monomethyl ether acetate 30.0
The mixture was fitted with a water separator, and 85.0 parts of methanol and water were distilled off at 70 to 90 ° C. to obtain a solvent-replaced monodispersed crosslinked fine particle dispersion having a solid content of 25%. Examples 25 to 27 Polymerization was carried out in the same manner as in Example 26, except that methanol to be charged in advance to the reaction vessel was changed to a mixed solvent of methanol and water, and methanol and water were charged at the mixing ratio shown in Table 1, and monodispersed crosslinked fine particles were used. A dispersion was obtained. Example 28 A reactor similar to that of Example 1 was charged with 84.5 parts of methanol, 13.8 parts of methyl methacrylate (manufactured by Wako Pure Chemical), 0.75 parts of benzyl methacrylate (manufactured by Wako Pure Chemical), and 0.45 part of divinylbenzene (manufactured by Wako Pure Chemical). Then, nitrogen gas was flowed to remove dissolved oxygen. After heating the reactor to 60 ° C, V-50 (Wako Pure Chemical Industries)
Dissolve 0.025 parts in 0.5 parts of ion-exchanged water and add
After heating and stirring for 0.1 hour, 0.15 parts of benzoyl peroxide (Nipper BW, manufactured by NOF Corporation) was added, and the mixture was further heated and stirred for 2 hours, solid content 15%, particle size 2.70 μm, variation coefficient 4
A 0.6% polydispersed crosslinked fine particle dispersion was obtained. Subsequently, propylene glycol monomethyl ether acetate 30.0
The mixture was fitted with a water separator, and 85.0 parts of methanol and water were distilled off at 70 to 90 ° C to obtain a solvent-replaced monodispersed crosslinked fine particle dispersion having a solid content of 25%. Example 29 In the same reactor as in Example 1, 84.5 parts of methanol, 13.8 parts of methyl methacrylate (manufactured by Wako Pure Chemical), 0.75 parts of benzyl methacrylate (manufactured by Wako Pure Chemical), 0.45 part of ethylene glycol dimethacrylate (manufactured by Wako Pure Chemical) , And dissolved oxygen was removed by flowing nitrogen gas. After heating the reactor to 60 ° C, V
-50 (manufactured by Wako Pure Chemical Industries, Ltd.) dissolved in 0.5 part of ion-exchanged water was added and stirred for 8 hours. Then, 0.15 part of benzoyl peroxide (Nipper BW, manufactured by NOF Corporation) was added, and further 2 hours Heat and stir, solid content 15%, particle size 2.2
A polydispersed crosslinked fine particle dispersion having a particle size of 6 μm and a coefficient of variation of 46.5% was obtained. Subsequently, 30.0 parts of propylene glycol monomethyl ether acetate was added, and a water separation tube was attached. At 70 to 90 ° C., 85.0 parts of methanol and water were distilled off, and a solvent-replaced monodispersed crosslinked fine particle dispersion having a solid content of 25% was added. Obtained. Comparative Example 1 The same reactor as in Example 1 was charged with 84.5 parts of methanol, 14.25 parts of methyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.), and 0.75 parts of benzyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.), and nitrogen gas was passed to remove dissolved oxygen. After heating the reactor to 60 ° C, V-50
A solution prepared by dissolving 0.025 part of 0.5 parts of ion-exchanged water (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was heated and stirred for 8 hours.
Further heat and stir for 2 hours, solid content 15%, particle size 2.82μ
m, a monodispersed crosslinked fine particle dispersion having a coefficient of variation of 23.6% was obtained. Comparative Example 2 70.5 parts of methanol, 14.5 parts of ion-exchanged water, 13.5 parts of methyl methacrylate (manufactured by Wako Pure Chemical Industries) were placed in the same reactor as in Example 1.
Parts, benzyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.75 parts, and allyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.75 parts were charged, and nitrogen gas was flowed to remove dissolved oxygen. After heating the reactor to 60 ° C, a solution prepared by dissolving 0.025 part of V-50 (manufactured by Wako Pure Chemical Industries, Ltd.) in 0.5 part of ion-exchanged water was added, followed by heating and stirring for 8 hours, and then benzoyl peroxide (Niper BW, manufactured by NOF Corporation). ) To 0.15
The mixture was further heated and stirred for 2 hours, and the solid content was 15%.
A monodispersed crosslinked fine particle dispersion having a particle size of 1.41 μm and a variation coefficient of 7.0% was obtained. The obtained monodispersed crosslinked fine particle dispersion was dried with a spray dryer to obtain a powder of monodispersed crosslinked fine particles. This was added to propylene glycol monomethyl ether acetate to obtain a monodispersed crosslinked fine particle dispersion having a solid content of 25%.

Crosslinked fine particles in Examples and Comparative Examples,
Methods for measuring the physical properties and properties of the crosslinked fine particle dispersion are as described below.

The particle size and particle size distribution of the crosslinked fine particles were measured by a laser diffraction scattering particle size meter (Microtrack 9340-UPA manufactured by Nikkiso Co., Ltd.) and a field emission scanning electron microscope (FE-SEM S-4500 manufactured by Hitachi, Ltd.). Performed in The heat resistance of the crosslinked fine particles is determined by the decomposition temperature of TG / DTA (TG / DTA200 manufactured by Seiko Instruments)
Optical microscope of fine particle shape after pressing for 3 minutes at 100kg / cm ² (OL
Evaluation was performed by observation using a YMPUS BX60).

The solvent resistance of the crosslinked fine particles is as follows.
It was evaluated from the gel fraction of the crosslinked fine particles when 2.0 g was dispersed in 98 g of methyl ethyl ketone.

The dispersibility of the crosslinked fine particles in the resin is 25%
20g of cross-linked fine particle dispersion, commercially available resin (Dianal BR-
101; manufactured by Mitsubishi Rayon Co., Ltd.) and a mixed solution of propylene glycol monomethyl ether acetate (50 g) was applied to a glass plate, and the dispersion state was observed with an optical microscope (BX60 manufactured by OLYMPUS).

Table 1 shows the results obtained in the examples and comparative examples.

[0047]

【table 1】

[0048]

In the examples, crosslinked fine particles having good heat resistance and solvent resistance were obtained. In Comparative Example 1, fine particles having extremely low heat resistance and solvent resistance were obtained because no crosslinkable monomer was used, and solvent replacement was not possible. In the examples, a composition in which fine particles were well dispersed in the resin and fine particles were uniformly dispersed in the state of primary particles was obtained. In Comparative Example 2, since the dried fine particles were added to the resin without replacing the organic solvent, the dispersibility of the fine particles in the resin was poor, and a large number of secondary particles were observed.

[0050]

According to the present invention, it is possible to provide a dispersion of crosslinked fine particles which can be uniformly dispersed in the resin in the state of primary particles when the crosslinked fine particles are added to the resin.

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[Procedure amendment]

[Submission date] April 5, 2002 (2002.4.5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Formula 1] [Wherein, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, or an aromatic substituent. ] Equation (2)

[Formula 2] [Wherein, R ³ and R ⁴ each independently represent an alkylene group or a divalent aromatic substituent. ]

Claims (7)

[Claims] A dispersion of crosslinked fine particles obtained by polymerizing a non-crosslinkable monomer (A) and a crosslinkable monomer (B) in a solvent (C) using a polymerization initiator. A dispersion obtained by replacing the contained solvent (C) with an organic solvent (E) having a higher boiling point than the solvent (C) and not dissolving the crosslinked fine particles. 2. The cross-linkable monomer (B) is a polyfunctional monomer having a polymerizable unsaturated carboxylic acid residue and a reactive functional group other than the polymerizable unsaturated carboxylic acid residue. 2. The dispersion according to claim 1, wherein 3. The dispersion according to claim 1, wherein the crosslinked fine particles have an average particle size of 0.5 to 3 μm. 4. The crosslinked fine particles have a decomposition temperature of 240 ° C. or higher and a gel fraction of 95% or higher.
A dispersion as described. 5. The crosslinked fine particles, in the absence of a dispersion stabilizer,
The dispersion according to any one of claims 1 to 3, wherein the dispersion is obtained by polymerization using a polymerization initiator represented by the following formula (1) or (2). Formula (1) [Wherein, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, or an aromatic substituent. ] Formula (2) [Wherein, R ³ and R ⁴ each independently represent an alkylene group or a divalent aromatic substituent. ] 6. The dispersion according to claim 1, wherein the solvent (C) is a mixed solvent of water and alcohol. A solvent contained in a crosslinked fine particle dispersion (D) obtained by polymerizing a non-crosslinkable monomer (A) and a crosslinkable monomer (B) in a solvent (C) using a polymerization initiator. A method for synthesizing a crosslinked fine particle dispersion, wherein C) is replaced with an organic solvent (E) having a higher boiling point than the solvent (C) and not dissolving the crosslinked fine particles.