KR20240005052A - Polymer particles and method for producing the same - Google Patents

Abstract

The object of the present invention is to provide polymer particles that achieve both monodisperse and high hardness, and a method for producing the same. The polymer particle of the present invention is made by polymerizing (meth)acrylic acid ester (A) having a cyclic ether structure, and further has a structure formed by ring-opening polymerization of cyclic ether moieties in the cyclic ether structure. It is characterized by including.

Description

Polymer particles and method for producing the same

The present invention relates to polymer particles and methods for producing the same.

In connecting semiconductor elements, wiring boards, etc., a connection method using an anisotropic conductive material is widely used to electrically connect a plurality of opposing electrodes or wiring. An anisotropic conductive material is a material in which conductive particles are dispersed in a binder resin (adhesive), and examples include an anisotropic conductive paste (ACP) and an anisotropic conductive film (ACF).

The conductive particles used for anisotropic conductive connection are formed by covering the polymer particles serving as the core with a metal layer. In recent years, in order to improve the performance of anisotropic conductive materials, development of conductive particles contained in anisotropic conductive materials is in progress. Since the compression deformation characteristics of the conductive particles are strongly influenced by the characteristics of the core polymer particles, increased hardness of the polymer particles is required to increase connection reliability during pressure connection. In addition, polymer particles used in anisotropic conductive materials are required to be monodisperse from the viewpoint of connection reliability.

Patent Document 1 includes a step (a) of obtaining a base particle by radically polymerizing a polymerizable monomer having a double bond and a functional group capable of reacting with an amino group, and, after step (a), contacting the base particle with an amino compound having an amino group. A cross-linked polymer particle obtained through a step (b) of further cross-linking the cross-linked polymer by reaction between a functional group and an amino group is disclosed. The crosslinked polymer particles described in Patent Document 1 are characterized by having good compression properties.

In addition, Patent Document 2 discloses a method for producing crosslinked fine particles, comprising a step of absorbing a compound having two or more amino groups into organic fine particles having a glycidyl group, and a crosslinking step of reacting the glycidyl group with the amino group. and crosslinked particles produced by the production method are disclosed. The crosslinked fine particles described in Patent Document 2 are monodisperse and are characterized by excellent solvent resistance and heat resistance.

International Publication No. 2011/158761 Japanese Patent Application Publication No. 2001-206954

The polymer particles proposed in Patent Document 1 and Patent Document 2 mentioned above had insufficient coexistence of monodispersity and high hardness. The object of the present invention is to provide polymer particles that achieve both monodisperse and high hardness, and a method for producing the same.

The present inventors have diligently studied to solve the above problems. As a result, the above problem can be solved by ring-opening polymerizing the cyclic ether site by adding an imidazole compound or/and an amino compound having a tertiary amino group to polymer particles containing a (meth)acrylic resin having a cyclic ether structure. By finding out this, we came to complete the present invention. The present invention relates to, for example, the following [1] to [8].

[1] Polymer particles comprising a (meth)acrylic resin having a structure obtained by polymerizing (meth)acrylic acid ester (A) having a cyclic ether structure and ring-opening polymerization of cyclic ether moieties in the cyclic ether structure. .

[2] The polymer particle according to [1], wherein the (meth)acrylic resin further contains a structure derived from a polymerizable monomer (B) other than the (meth)acrylic acid ester (A) having the cyclic ether structure. .

[3] The polymer particle according to [2] above, wherein the polymerizable monomer (B) is at least one compound selected from the group consisting of monomers having 1 to 4 (meth)acryloyl groups in one molecule.

[4] The polymer particle according to any one of [1] to [3], wherein the (meth)acrylic acid ester (A) having the cyclic ether structure is a compound represented by the following formula (1).

In formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, x represents an integer of 1 to 6, and Y represents a single bond or -O-CH. ₂ represents -, and z represents an integer from 0 to 2.]

[5] A (meth)acrylic acid having a structure obtained by polymerizing (meth)acrylic acid ester (A) having the cyclic ether structure and adding an imidazole compound to a ring-opened portion of the cyclic ether structure. The polymer particle according to any one of [1] to [4] above, comprising a resin.

[6] The polymer particle according to any one of [1] to [5] above, wherein the polymer particle has a 10% K value of 3,000 to 7,000 N/mm ² .

[7] A method for producing polymer particles according to any one of [1] to [6] above,

A step (1) of radically polymerizing a polymerizable monomer component containing (meth)acrylic acid ester (A) having a cyclic ether structure to obtain a base particle containing a (meth)acrylic resin,

The parent particle is brought into contact with an imidazole compound or/and an amino compound having a tertiary amino group, ring-opening polymerizes the cyclic ether moieties in the cyclic ether structure, and the cyclic ether moieties undergo ring-opening polymerization to form a (meta) compound having a structure formed by ring-opening polymerization. ) Process (2) of obtaining polymer particles containing an acrylic resin,

A method for producing polymer particles, comprising the step (3) of powdering the polymer particles.

[8] The polymer particles according to any one of [1] to [6] above, used as conductive particles of an anisotropic conductive adhesive.

According to the present invention, polymer particles that achieve both monodispersity and high hardness can be provided, and a method for producing the same.

Hereinafter, the polymer particles of the present invention and their production method will be described in detail.

[Polymer particles]

The polymer particles of the present invention contain a (meth)acrylic resin. The (meth)acrylic resin is formed by polymerizing (meth)acrylic acid ester (A) having a cyclic ether structure, and has a structure formed by ring-opening polymerization of cyclic ether moieties in the cyclic ether structure.

Additionally, in this specification, (meth)acrylic is used as a general term for acrylic and methacrylic, and may be either acrylic or methacrylic. (Meth)acrylate is used as a general term for acrylate and methacrylate, and may be either acrylate or methacrylate. (Meth)acryloyl is used as a general term for acryloyl and methacryloyl, and may be either acryloyl or methacryloyl.

In the present invention, “(meth)acrylic resin” refers to a structural unit derived from (meth)acrylic acid, a structural unit derived from acrylate, a structural unit derived from acrylic acid ester, a structural unit derived from methacrylic acid, and a structural unit derived from methacrylate. and a resin in which the total of structural units derived from methacrylic acid ester is 50% by mass or more based on 100% by mass of all structural units of the (meth)acrylic resin.

By containing the above-mentioned (meth)acrylic resin, the polymer particles of the present invention can achieve both monodispersity and high hardness.

[Method for producing polymer particles]

The method for producing polymer particles of the present invention is

A step (1) of radically polymerizing a monomer component containing (meth)acrylic acid ester (A) having a cyclic ether structure to obtain a base particle containing a (meth)acrylic resin,

The parent particle is brought into contact with an imidazole compound or/and an amino compound having a tertiary amino group, ring-opening polymerizes the cyclic ether moieties in the cyclic ether structure, and the cyclic ether moieties undergo ring-opening polymerization to form a (meta) compound having a structure formed by ring-opening polymerization. ) Process (2) of obtaining polymer particles containing an acrylic resin,

It includes a step (3) of powdering the polymer particles.

The method for producing polymer particles of the present invention can complete the synthesis in one pot from the step of producing particles before crosslinking to obtaining the polymer particles through the crosslinking reaction, making it possible to simplify the production work.

<Process (1)>

The mother particle containing a (meth)acrylic resin is obtained by radically polymerizing a polymerizable monomer component containing (meth)acrylic acid ester (A) having a cyclic ether structure by a known method.

≪(Meth)acrylic acid ester (A) with cyclic ether structure≫

(Meth)acrylic acid ester (A) having a cyclic ether structure (hereinafter also referred to as “(meth)acrylic acid ester (A)”) is not particularly limited as long as it is a (meth)acrylic acid ester having a cyclic ether structure in the molecule, and is known. (meth)acrylic acid esters having a cyclic ether structure can be widely used.

Examples of cyclic ether structures include oxacyclopropane (oxilane), oxacyclobutane (oxetane), oxacyclopentane (tetrahydrofuran), oxacyclohexane (tetrahydropyran), and 1,4-dioxacyclohexane (1). ,4-dioxane), 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 1,4-epoxycyclohexane, 1-methyl-1,2-epoxycyclohexane, exo-2,3-epoxy Norbornane, etc. can be mentioned. Among these, oxilane is preferable from the viewpoint of high reactivity and easy ring-opening polymerization of cyclic ether moieties using a catalyst.

(Meth)acrylic acid ester (A) has a structure in which a cyclic ether structure is directly or indirectly bonded to the oxygen atom of (meth)acrylic acid ester, for example, the oxygen atom of the ester represented by the following formula (I) and the cyclic ether Interposed between structures.

(In formula (I), m represents an integer of 1 to 7.)

(Meth)acrylic acid ester (A) is preferably a compound represented by the following formula (1), and more preferably a compound represented by the following formula (2).

[In formulas (1) and (2), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, x represents an integer of 1 to 6, and Y represents only represents a bond or -O-CH ₂ -, and z represents an integer of 0 to 2.]

In formulas (1) and (2), from the viewpoint of ensuring polymerization stability of the polymer particles while increasing the crosslinking density of the polymer particles, the upper limit of the number of carbon atoms of the alkyl group of R ² is preferably 6, and more preferably 3. and, more preferably, it is 2, and as R ² , a hydrogen atom is particularly preferable; x is preferably 1 to 4; It is preferable that z is 0 or 1, and it is more preferable that z is 0.

Examples of compounds represented by formula (2) include glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, glycidyloxy (poly)alkylene glycol (meth)acrylate, Examples include methylglycidyl (meth)acrylate and 4-hydroxybutylacrylate glycidyl ether.

Among these, glycidyl (meth)acrylate and 4-hydroxybutylacrylate glycidyl ether are preferred from the viewpoint of ensuring polymerization stability of the polymer particles while increasing the crosslinking density of the polymer particles.

These compounds may be used individually, or two or more types may be used.

The content of the structural unit derived from (meth)acrylic acid ester (A) in the (meth)acrylic resin is preferably 5 to 90% by mass, based on 100% by mass of all structural units of the (meth)acrylic resin. It is preferably 10 to 80 mass%, more preferably 10 to 50 mass%, and particularly preferably 10 to 30 mass%.

If the content of the structural unit derived from the (meth)acrylic acid ester (A) is within the above range, polymerization stability of the polymer particles and ring-opening polymerization of the cyclic ether moiety by the catalyst can be achieved at the same time.

The content of the structural unit derived from (meth)acrylic acid ester (A) can be calculated from the amount of (meth)acrylic acid ester (A) in the polymerizable monomer component used when producing the (meth)acrylic resin.

≪Polymerizable monomer (B)≫

In the polymer particles of the present invention, it is preferable that the (meth)acrylic resin further contains a structure derived from a polymerizable monomer (B) other than the (meth)acrylic acid ester (A). By including the polymerizable monomer (B), the resulting polymer particles are excellent in monodisperse and have high hardness.

In step (1), polymer particles further containing a structure derived from the polymerizable monomer (B) can be obtained by radically polymerizing the polymerizable monomer (B) together with the (meth)acrylic acid ester (A).

The polymerizable monomer (B) is not particularly limited as long as it can be copolymerized with the (meth)acrylic acid ester (A), and examples include monofunctional monomers such as (meth)acrylic acid monomers, styrene monomers, functional group-containing monomers, and conjugated dienes. Systemic monomers, monomers forming polyurethane resins, polyols, etc. are included, and at least one compound selected from the group consisting of monomers having 1 to 4 functional groups per molecule is preferred. It is more preferable that it is at least 1 type of compound chosen from the group which consists of monomers which have 1-4 (meth)acryloyl groups.

Examples of the (meth)acrylic acid-based monomer include (meth)acrylic acid alkyl ester; Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylic acid Octyl, nonyl (meth)acrylate, decyl (meth)acrylate and dodecyl (meth)acrylate, etc.

(meth)acrylic acid aryl ester; (meth)acrylic acid phenyl and (meth)acrylic acid benzyl, etc.

(meth)alkoxyalkyl acrylate; (meth)acrylic acid methoxyethyl, (meth)acrylic acid ethoxyethyl, (meth)acrylic acid propoxyethyl, (meth)acrylic acid butoxyethyl and (meth)acrylic acid ethoxypropyl, etc.,

Salts such as (meth)acrylic acid and (meth)acrylic acid alkali metal salt;

(meth)acrylic acid ester of alicyclic alcohol; (meth)cyclohexyl acrylate; (meth)acrylic acid isobornyl, etc. are mentioned.

Examples of styrene-based monomers include alkyl styrene such as styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, and octyl styrene, and fluoromethyl styrene. Styrene, chlorostyrene, bromostyrene, dibromostyrene, chlormethylstyrene, iodinated styrene, nitrostyrene, acetylstyrene, methoxystyrene, α-methylstyrene, vinyltoluene, etc. are mentioned.

Examples of functional group-containing monomers include:

Polymerizable compounds containing oxazoline groups; 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline and 2-isopropenyl-2-oxazoline, etc.,

Polymerizable compounds containing an aziridine group; (meth)acryloyl aziridine, (meth)acrylic acid-2-aziridinyl ethyl, etc.,

Vinyl monomer containing an epoxy group; Allyl glycidyl ether, (meth)acrylic acid glycidyl ether, and (meth)acrylic acid-2-ethylglycidyl ether, etc.,

Vinyl compounds containing hydroxyl groups; (meth)acrylic acid-2-hydroxyethyl, (meth)acrylic acid-2-hydroxypropyl, (meth)acrylic acid-2-hydroxybutyl, monoester and lactic acid between (meth)acrylic acid and polypropylene glycol or polyethylene glycol Adducts of tones with (meth)acrylic acid-2-hydroxyethyl, etc.

fluorinated vinyl monomer; Fluorine-substituted (meth)acrylic acid alkyl ester, etc.

Carboxyl group-containing vinyl monomer; Unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, crotonic acid, maleic acid, and fumaric acid, their salts, and their (partial) ester compounds and acid anhydrides, etc.

reactive halogen-containing vinyl monomers; (meth)acrylic acid-2-chloroethyl, 2-chlorethyl vinyl ether, vinyl monochloroacetate and vinylidene chloride, etc.

Vinyl monomer containing amide group; (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxyethyl (meth)acrylamide and N-butoxymethyl (meth)acrylamide, etc.,

Vinyl compound monomer containing an organosilicon group; Vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine and 2-methoxyethoxytrimethoxysilane, etc.,

Other macro monomers; A material having a radically polymerizable vinyl group at the end of a copolymer of the above monomers (e.g., a fluorine-based macromonomer, a silicon-containing macromonomer, a urethane-based macromonomer),

acrylonitrile; Vinyl acetate; can be mentioned.

Conjugated diene monomers include butadiene, isoprene, and chloroprene.

As the monomer forming the polyurethane resin, polyols containing glycol as a main component and diisocyanate raw materials can be used, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, etc. aromatic diisocyanates, aliphatic diisocyanates, and bifunctional terminal isocyanate urethane prepolymers.

Examples of polyols include diol compounds such as ethylene glycol and diethylene glycol, and polyether glycols.

The polymerizable monomers may be used individually or in combination of two or more.

When the (meth)acrylic resin contains a structural unit derived from the polymerizable monomer (B), from the viewpoint of adjusting the polymerization stability and hardness of the resulting polymer particles, the content of the structural unit derived from the polymerizable monomer (B) is (meth) ) Preferably it is 15 to 90% by mass based on 100% by mass of the total structural units of the acrylic resin.

The content of the structural unit derived from the polymerizable monomer (B) can be calculated from the amount of the polymerizable monomer (B) in the monomer component used when producing the (meth)acrylic resin.

From the viewpoint of adjusting the hardness of the resulting polymer particles, a polyfunctional monomer may be used as the polymerizable monomer (B) within a range that does not impair the effect of the present invention.

Examples of polyfunctional monomers include:

bifunctional monomer; Ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyoxyethylene di(meth)acrylate, Neo Pentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, divinylbenzene etc,

trifunctional monomer; Trimethylolpropane triacrylate, trimethylolethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, Propoxylated trimethylolpropane tri(meth)acrylate, tris(2-(meth)acryloxyethyl isocyanurate), etc.,

Monomers with tetrafunctional or higher function; Pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, ethoxylated dipenta Erythritol tetra(meth)acrylate, propoxylated dipentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated ditrimethylolpropane tetra(meth)acrylate and ethoxylated ditrimethyl. Tetra(meth)acrylate compounds such as all-propane tetra(meth)acrylate,

Diisocyanate compounds having aliphatics among diisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diisocyanatemethylcyclohexane, isophorone diisocyanate, and methylenebis(4-cyclohexylisocyanate), or diisocyanatemethylbenzene or an adduct obtained by addition reaction between a diisocyanate compound having an aromatic group such as 4,4,-diphenylmethane diisocyanate and glycidol di(meth)acrylate,

Dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. can be mentioned.

≪Radical polymerization≫

The parent particle containing a (meth)acrylic resin is obtained by radically polymerizing the above-mentioned (meth)acrylic acid ester (A) and, if necessary, a polymerizable monomer (B) by a known method.

This method includes, for example, a method of emulsification or suspension polymerization in the presence of a radical polymerization initiator, or a method of polymerizing the monomer by swelling it with a radical polymerization initiator using non-crosslinked seed particles (so-called seed polymerization method), soap-free Polymerization methods in an aqueous medium such as emulsion polymerization method can be mentioned. Among these polymerization methods, it is preferable to use the seed polymerization method since it is possible to obtain mother particles with a particle diameter of several μm and an even particle diameter.

(Radical polymerization initiator)

As radical polymerization initiators that can be used in the above polymerization, persulfates such as potassium persulfate and ammonium persulfate; Peroxides such as benzoyl peroxide and lauryl peroxide; Azo compounds such as azobisisobutyronitrile can be mentioned. The polymerization initiator may be used individually, or two or more types may be used in combination. The amount of polymerization initiator used is preferably 0.1 to 10 parts by mass per 100 parts by mass of the monomer component.

(emulsifier)

Emulsifiers that can be used in the above polymerization include, for example, alkyl sulfonates such as sodium dodecyl sulfonate; Alkylbenzenesulfonate salts such as sodium dodecylbenzenesulfonate; alpha-sulfone fatty acid ester salts such as sodium 2-sulfotetradecanoic acid 1-methyl ester; Polyethylene glycol alkylaryl ethers such as polyethylene glycol nonylphenyl ether; Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether; Examples include salts of polyoxyethylene polycyclic phenyl ether, allyl ether, and their sulfuric acid esters. Among these, alkylbenzene sulfonate is preferable. Emulsifiers may be used individually, or two or more types may be used in combination. The amount of emulsifier used is preferably 0.01 to 20 parts by mass per 100 parts by mass of the monomer component.

(Dispersion stabilizer)

Dispersion stabilizers that can be used in the above polymerization include, for example, partially saponified polyvinyl alcohol; Fully saponified polyvinyl alcohol; polyacrylic acid, its copolymers and their neutralized products; polymethacrylic acid, its copolymers and their neutralized products; Cellulose such as carboxymethylcellulose and hydroxypropylmethylcellulose; Examples include polyvinylpyrrolidone. The dispersion stabilizer may be used individually, or two or more types may be used in combination. The amount of the dispersion stabilizer used is preferably 0.1 to 10 parts by mass per 100 parts by mass of the monomer component.

Aqueous media that can be used for the above polymerization include water and a mixture of water and a hydrophilic organic solvent.

Examples of water include purified water (e.g., ion exchange water, distilled water), ground water, and tap water.

Examples of hydrophilic organic solvents include lower alcohols such as methanol, ethanol, and isopropanol; polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, diethylene glycol, and triethylene glycol; Cellosolves such as methyl cellosolve and ethyl cellosolve; Ketones such as acetone; ethers such as tetrahydrofuran; Ester, such as methyl formate, can be mentioned.

The hydrophilic organic solvent may be used individually, or two or more types may be used together. The amount of hydrophilic organic solvent added is usually 10 parts by mass or less per 100 parts by mass of water. In this specification, unless otherwise specified, “aqueous medium” refers to the above-mentioned medium.

In the above polymerization method, the polymerization temperature is usually 40 to 100°C, preferably 55 to 85°C, and the polymerization time is usually 1 to 24 hours, preferably 1 to 10 hours. In the case of seed polymerization, the above polymerization conditions can be adopted in each step.

Seed polymerization is a polymerization method that uses seeds when performing polymerization. The seed polymerization is preferably carried out as seed emulsion polymerization, which is a type of emulsion polymerization. In seed emulsion polymerization, the step of nucleation within the system in normal emulsion polymerization can be replaced by a seed. By using seeds with uniform particle diameters and sufficiently swelling the seeds with monomer before polymerization, resin particles with large particle diameters and uniform particle diameters can be obtained.

When obtaining a (meth)acrylic resin by seed polymerization, the above-mentioned (meth)acrylic acid ester (A) and, if necessary, a polymerizable monomer (B) and other monomer components are copolymerized in the presence of seeds.

It is preferable to use monodisperse particles as seeds from the viewpoint of uniformizing the particle diameter of the (meth)acrylic resin. As the seed, it is preferable to use particles of a polymer of the alkyl (meth)acrylate exemplified as the monomer component above, for example, polymethyl methacrylate (PMMA) or polymethyl acrylate.

The seed polymerization may be repeated multiple times, and (meth)acrylic resin particles are usually obtained by performing the seed polymerization 1 to 15 times, preferably 1 to 10 times. In addition, when performing seed polymerization repeatedly, the resin particles obtained by the first seed polymerization are used as seeds (seeds) to be used in the second seed polymerization, and similarly, the resin particles obtained by the n-1 seed polymerization are used as seeds. Let be the seed (seed) used for the nth seed polymerization. Additionally, the examples of seeds described above are examples of seeds used for the first seed polymerization when seed polymerization is performed multiple times.

The average particle diameter of the seed used for the first seed polymerization, that is, the first seed polymerization, varies depending on what size is expected as the average particle diameter of the (meth)acrylic resin and the number of times the seed polymerization is repeated. However, seeds with an average particle diameter of 0.1 to 3.0 μm, preferably 0.1 to 2.0 μm, are used.

The seed is usually used in an amount of 1 to 50 parts by mass, preferably 1 to 30 parts by mass, per 100 parts by mass of the monomer component. In addition, when seed polymerization is performed multiple times, in each seed polymerization, 1 to 50 parts by mass, preferably 1 to 30 parts by mass, of seeds are used per 100 parts by mass of the monomer component.

Also, the CV value of the seed is preferably 10% or less, which has high monodispersity, and 2 to 8% is more preferable. Additionally, the CV value (Coefficient of Variation) is an index of the particle diameter distribution of particles, and is also called the coefficient of variation, and can be obtained by the following equation (II).

CV value [%]=(σ/D)×100···(II)

[In formula (II), σ is the standard deviation and D is the average particle diameter.]

The amount of each monomer used in the monomer component is preferably 5 to 90 parts by mass of (meth)acrylic acid ester (A), assuming the total of (meth)acrylic acid ester (A) and polymerizable monomer (B) is 100 parts by mass. 10 to 95 parts by mass of the polymerizable monomer (B), more preferably 10 to 80 parts by mass of the (meth)acrylic acid ester (A), and 20 to 90 parts by mass of the polymerizable monomer (B), more preferably 10 to 50 parts by mass of (meth)acrylic acid ester (A), 50 to 90 parts by mass of polymerizable monomer (B), particularly preferably 10 to 30 parts by mass of (meth)acrylic acid ester (A), polymerizable The monomer (B) is 70 to 90 parts by mass. Additionally, when a (meth)acrylic resin is obtained through a multi-step reaction such as seed polymerization, the amount of each monomer used may be within the above range when the total of all monomer components used in each step is 100 parts by mass.

In step (1), if necessary, the (meth)acrylic resin can be washed and dehydrated with ion-exchanged water using a Buchner funnel or the like.

<Process (2)>

In step (2), after step (1), the parent particle is brought into contact with an imidazole-based compound or/and an amino compound having a tertiary amino group to ring-open polymerize the cyclic ether moieties in the cyclic ether structure to form a cyclic ether. Polymer particles containing a (meth)acrylic resin having a structure formed by ring-opening polymerization of ether moieties are obtained.

The structure formed by ring-opening polymerization of cyclic ether moieties in the cyclic ether structure of the (meth)acrylic resin may be ring-opening polymerization of one type of cyclic ether moiety in the cyclic ether structure, or two or more different cyclic ether moieties may be ring-opening-polymerized with each other. Ring-opening polymerization may be performed.

Examples of the structure formed by ring-opening polymerization of cyclic ether moieties include a repeating unit represented by the following formula (3).

[In formula (3), P ¹ represents a polymer chain containing structural units derived from (meth)acrylic acid ester (A).]

For example, when glycidyl methacrylate is used as the polymerizable monomer, the structure formed by ring-opening polymerization of cyclic ether moieties is a structure represented by the following formula (4). In this case, the cyclic ether portions of the glycidyl methacrylate polymer, that is, the epoxy groups undergo ring-opening polymerization. Therefore, the obtained polymer particles have a repeating structure of the glycidyl methacrylate polymer chain in step (1), and also have a repeating structure formed by ring-opening polymerization of the epoxy groups of glycidyl methacrylate with each other in step (2). have

The content of the structural unit formed by ring-opening polymerization of cyclic ether moieties in the cyclic ether structure in the (meth)acrylic resin is preferably 5 to 90% by mass based on 100% by mass of all structural units of the (meth)acrylic resin. , more preferably 10 to 80 mass%, further preferably 10 to 50 mass%, particularly preferably 10 to 30 mass%.

If the content of the structure formed by ring-opening polymerization of cyclic ether moieties is within the above range, polymer particles with high hardness and excellent monodispersity can be obtained.

≪Imidazole-based compounds≫

The polymer particles of the present invention are formed by polymerizing (meth)acrylic acid ester (A) having a cyclic ether structure, and have a structure in which the cyclic ether portion is ring-opened by adding an imidazole-based compound to a part of the cyclic ether structure. It is preferable that it contains a meth)acrylic resin.

Examples of the imidazole-based compound include an imidazole-based compound having an active hydrogen at the first position shown in the following formula (5), or an imidazole-based compound having no active hydrogen at the first position shown in the following formula (6).

[In formulas (5) and (6), R ³ and R ⁶ represent an organic group, and R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.]

Examples of imidazole-based compounds having active hydrogen at position 1 shown in formula (5) include 2-ethyl-4-methylimidazole, 2-phenyl-1H-imidazole, 2-methylimidazole, 4 -Methyl-1H-imidazole-5-carboxylic acid ethyl, 2-isopropylimidazole, 1H-imidazole-4,5-dicarboxylic acid, benzoimidazole, 2-phenyl-5-benzimidazole Examples include sulfonic acid, 2-hydroxybenzimidazole, 4-methylimidazole, and 5,6-dimethylbenzimidazole.

Examples of the imidazole-based compound that does not have an active hydrogen at position 1 shown in formula (6) include 2,4-diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1 ,3,5-triazine, 1-isobutyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazolium·trimellitate, 1,2-dimethylimidazole, 1-benzyl -2-methylimidazole and 2-phenyl-1-benzyl-1H-imidazole.

Among the above imidazole compounds, 2-ethyl-4-methylimidazole is preferable from the viewpoint of reactivity and water solubility.

The said imidazole-based compound may be used individually, or 2 or more types may be used.

The amount of imidazole compound added in step (2) is 0.01 to 5.0 parts by mass, preferably 0.05 to 3.0 parts by mass, more preferably 0.1 to 2.0 parts by mass, based on 100 parts by mass of solid content of the mother particle.

The molecular weight of the imidazole-based compound is preferably 50 to 1,000, more preferably 50 to 500, and still more preferably 50 to 300.

In step (2), when an imidazole-based compound having an active hydrogen is used at the first position, the imidazole-based compound and the cyclic ether of a part of the side chain of the (meth)acrylic resin react with the active hydrogen of the imidazole-based compound. Thus, an imidazole-based compound can be added to the site where part of the cyclic ether structure is ring-opened.

As a structure in which an imidazole-based compound is added to a part of the above-mentioned cyclic ether structure and the cyclic ether site is ring-opened, for example, an imidazole-based compound having an active hydrogen at the first position is combined with a cyclic ether of a part of the side chain of a (meth)acrylic resin. Through reaction, the ether ring is ring-opened and an imidazole-based compound is added to form a structure represented by the following formula (7).

[In formula (7), R ³ represents an organic group, R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, P ² represents the main chain of a (meth)acrylic resin, and w represents an integer from 1 to 6.]

The structure in which the cyclic ether moiety is ring-opened by adding an imidazole-based compound to a part of the cyclic ether structure is a (meth)acrylic polymer constituting a (meth)acrylic resin having a structure formed by ring-opening polymerization of the cyclic ether moieties with each other. It may be in the same molecule, or it may be in a molecule of a (meth)acrylic polymer separate from the above-mentioned (meth)acrylic polymer.

When the polymer particle of the present invention has a structure in which the cyclic ether moiety is ring-opened by adding an imidazole-based compound to a part of the cyclic ether structure, the balance with the amount of cyclic ether moiety reacting during ring-opening polymerization between cyclic ether moieties From the viewpoint, the content of the structural unit in which the cyclic ether moiety is ring-opened by adding an imidazole-based compound is preferably 5 to 90% by mass, more preferably 10% by mass, based on 100% by mass of the total structural units of the polymer particle. ~80% by mass, more preferably 10-50% by mass, particularly preferably 10-30% by mass.

≪Amino compounds having a tertiary amino group≫

Examples of amino compounds having a tertiary amino group include trimethylamine, triethylamine, tributylamine, trioctylamine, N-methylmorpholine, N-ethylmorpholine, N,N-dimethylethanolamine, N,N -Diethylethanolamine, N,N-dibutylethanolamine, N-methyldiethanolamine, N-n-butyldiethanolamine, N-t-butyldiethanolamine, N,N-diethylisopropanolamine, 1-methylimida Sol, 1,8-diazabicyclo[5.4.0]undeca-7-ene, and polyethyleneimine are included.

Among these, from the viewpoint of obtaining polymer particles that are both monodisperse and highly hardened by ring-opening polymerization of cyclic ether moieties, amino compounds having only tertiary amino groups but not primary and/or secondary amino groups in the molecule of the compound are used. Compounds are preferred.

Compounds having a tertiary amino group, unlike compounds having a primary or secondary amino group, advance the reaction as a polymerization catalyst. The tertiary amine produced after the reaction between an amino compound having a primary or secondary amino group and a cyclic ether group is unlikely to have a catalytic function due to steric hindrance, but the compound having a tertiary amino group is strongly basic, so it has a catalytic function and can be used as a cyclic ether. The sites can be ring-opened polymerized.

The addition amount of the amino compound having a tertiary amino group in step (2) is 0.01 to 5.0 parts by mass, preferably 0.05 to 3.0 parts by mass, more preferably 0.1 to 2.0 parts by mass, based on 100 parts by mass of solid content of the mother particle. It is wealth.

The average molecular weight of the amino compound having a tertiary amino group is preferably 50 to 2,000, more preferably 50 to 500, and still more preferably 50 to 200.

In step (2), one or more types of imidazole-based compounds or amino compounds having a tertiary amino group can be used, and the imidazole-based compound and the amino compound having a tertiary amino group can be used as long as the effect of the present invention is not impaired. You can use it together. Among these, it is more preferable to use an imidazole-based compound because the polymer particles can be further increased in hardness.

≪Other ingredients≫

In step (2), other components may be used as needed along with the imidazole-based compound or the amino compound having a tertiary amino group. Other components include, for example, amino compounds having a primary amino group and/or amino compounds having a secondary amino group.

As an amino compound having a primary amino group, for example

alkyldiamine;

Mensenediamine, isophoronediamine, xylenediamine, diethylenetriamine (including secondary amines), trimethylenetetramine (including secondary amines), tetraethylenepentamine (including secondary amines), 1,3-bis (amino Alicyclic amines such as methyl)cyclohexane, diethylaminopropylamine, and 4,4'-methylenebis(2-methylcyclohexanamine);

and aromatic amines such as m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, and 1,3-bis(3-aminophenoxy)benzene. .

Examples of amino compounds having a secondary amino group include:

Methylcyclohexylamine, diethylenetriamine (including primary amines), trimethyltetramine (including primary amines), tetraethylenepentamine (including primary amines);

Aromatic amines such as 4,4'-methyleneaniline can be mentioned.

When using a compound having a primary amino group and/or a secondary amino group, the amount of the compound having a primary amino group and/or a secondary amino group is preferably 0.7 parts by mass or less per 100 parts by mass of the solid content of the parent particle. .

If the amount used is below the above value, ring-opening polymerization can be carried out between the cyclic ether moieties of (meth)acrylic acid ester (A) without impairing the catalytic action of the imidazole-based compound or the amino compound having a tertiary amino group.

If the amount used exceeds the above range, an addition reaction between the cyclic ether moiety present on the surface of the polymer particles and the primary amino group and/or secondary amino group occurs, resulting in the problem that curing is completed without some of the cyclic ether reacting.

In step (2), when an imidazole-based compound having active hydrogen is used at the first position, after the imidazole-based compound is added to the site where part of the cyclic ether structure is ring-opened, the imidazole-based compound becomes a catalyst and It is thought that it promotes ring-opening polymerization between the cyclic ether portions of the particles.

On the other hand, in step (2), when an imidazole-based compound or an amino compound having a tertiary amino group that does not have an active hydrogen is used in the first position, the imidazole-based compound or an amino compound having a tertiary amino group has a cyclic ether structure. It is thought that it promotes ring-opening polymerization between the cyclic ether portions of the parent particle as a catalyst without being added to a portion of the .

In this ring-opening polymerization, the imidazole-based compound or the amino compound having a tertiary amino group is mixed with the (meth)acrylic acid ester (A) having a cyclic ether structure at a molar ratio (imidazole or amino compound having a tertiary amino group/cyclic The (meth)acrylic acid ester (A)) having an ether structure is preferably 0.001 to 0.4, and more preferably 0.002 to 0.2. Since the imidazole-based compound and the amino compound having a tertiary amino group act as a catalyst for ring-opening polymerization of cyclic ether moieties, if the molar ratio is within the above range, the anion polymerization reaction sufficiently proceeds. Ring-opening polymerization can be performed, for example, at 100 to 200°C for 0.5 to 2 hours.

<Process (3)>

In step (3), the polymer particles obtained in step (2) are powdered.

The method for separating the polymer particles from the dispersion medium is not particularly limited, and known methods such as filtration and centrifugation can be used. Next, the separated polymer particles can be dried and powdered by using commonly used methods such as freeze-drying and spray drying.

Considering the hardness of the polymer particles, it is preferable to dry them under conditions without deformation of the particles.

It is preferable to grind the dried polymer particles using a mortar, jet mill, etc.

[Physical properties of polymer particles]

The polymer particles of the present invention are not particularly limited, but the average particle diameter is preferably 2 to 20 μm, more preferably 2 to 5 μm. If the average particle diameter is below the above range, there is a possibility that the polymer particles become prone to agglomeration. In addition, in this specification, all "average particle diameters" including the average particle diameter used to calculate the CV value or 10% K value of the polymer particle can be determined by the measurement method described in the Examples.

The CV value of the polymer particles is preferably 15% or less, more preferably 7% or less. When the CV value exceeds the above range, the properties of the polymer particles in various uses tend to deteriorate. For example, when polymer particles are used as conductive particles constituting an anisotropic conductive adhesive, connection reliability tends to decrease. Additionally, the CV value of the particle diameter can be obtained by the same method as the description of the CV value of the seed described above.

The polymer particles of the present invention preferably have a 10% K value of 3,000 to 7,000 N/mm ² and more preferably 3,300 to 6,000 N/mm ² as determined by the formula below.

10% K value (N/mm ² )=(3/√2)·F·S ^-3/2 ·R ^-1/2

[F and S are the load value (N) and compressive displacement (mm) at 10% compressive deformation of the polymer particle, respectively, and R is the radius of the polymer particle (mm), and the polymer measured by the method described in the Examples It is half the average particle diameter of the particle.]

If the 10% K value of the polymer particles is too small, when used as an anisotropic conductive material, the binder (adhesive) around the conductive particles cannot be sufficiently removed (cannot be spread out) or the penetration into the electrode is weak. Due to the contact falling off, a low connection resistance value may not be obtained. On the other hand, if the 10% K value of the polymer particles is too large, the actual contact area involved in electronic conduction increases and the resistance value decreases, but the connection portion may be damaged and a good electrical contact state may not be secured.

The 10% K value is a value calculated from the compressive load when the particle diameter is deformed by 10%, and represents the hardness of the sphere universally and quantitatively. The specific measurement method of the 10% K value is described in the Examples described later.

The polymer particles of the present invention preferably have a so-called breaking point where the particles break before reaching the maximum load when compressed.

A method of obtaining polymer particles having a breaking point includes a method of forming a three-dimensional network structure in the obtained polymer by including a polyfunctional monomer as a polymer constituting the polymer particle. Also, even in the case where the polymer is composed only of monofunctional monomers, a method of advancing ring-opening polymerization of the epoxy groups of the uncrosslinked polymer by contacting the polymer with a compound having a tertiary amino group or an imidazole-based compound as a post-addition catalyst can be used.

[Use of polymer particles]

The uses of the polymer particles of the present invention are not particularly limited, but for example, include the field of electrical and electronic materials such as conductive particles for anisotropic conductive adhesives, various spacers, modifiers for the sliding properties of resin films, additives for rheology control, and shot applications. It is used in blasting agents, abrasives, and carriers for chromatography. It is preferable to apply the polymer particles of the present invention to polymer particles that become the core of the conductive particles used in an anisotropic conductive adhesive from the viewpoint of exhibiting the effects of the present invention.

<Anisotropic conductive adhesive>

When using the polymer particles of the present invention for an anisotropic conductive adhesive, conductive particles are obtained by providing a conductive metal layer on the surface of the polymer particles. The method for forming the metal layer on the surface of the polymer particles is not particularly limited, and examples include electroless plating, coating with a paste obtained by mixing metal fine powder alone or with a binder, vacuum deposition, ion plating, and ion plating. Physical vapor deposition methods such as sputtering, etc. can be mentioned. More specifically, examples include the method described in Japanese Patent Application Laid-Open No. 2000-319309.

The anisotropic conductive adhesive just needs to contain the above-described conductive particles and binder resin, and there are no particular restrictions on other components, and components conventionally included in anisotropic conductive adhesives can be used without particular restrictions.

The binder resin is not particularly limited as long as it is an insulating resin, and examples include thermoplastic resins such as acrylic resins, ethylene-vinyl acetate resins, and styrene-butadiene block copolymers, monomers and oligomers having a glycidyl group, and curing agents such as isocyanates. A curable resin composition that hardens by reaction, a curable resin composition that hardens by light or heat, and the like can be mentioned.

Additionally, depending on the adhesive manufacturing method, the anisotropic conductive adhesive can be formed into a film or paste form, and the dispersion method can be appropriately changed depending on the form. Film-shaped anisotropic conductive adhesive (anisotropic conductive film) is obtained by molding a mixture of conductive particles dispersed in a resin component into a film, and the anisotropic conductive paste is obtained by adjusting the viscosity, etc. of the mixture obtained in the same manner as the anisotropic conductive film using a solvent. It is obtained by adjusting.

When the polymer particles of the present invention are used in an anisotropic conductive adhesive, the amount of polymer particles per 100 parts by mass of the anisotropic conductive adhesive is preferably 5 to 60 parts by mass, more preferably 10 to 50 parts by mass. If the content of the conductive particles is too small, sufficient electrical conduction may be difficult to obtain. On the other hand, if the content of the conductive particles is too large, the conductive particles may come into contact with each other, making it difficult to function as an anisotropic conductive material. .

An anisotropic conductive adhesive can be obtained, for example, by mixing or kneading at least conductive particles and an adhesive. Usually, it can be obtained by mixing or kneading conductive particles, an adhesive, a curing agent, and an organic solvent.

(Example)

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples. In descriptions such as the examples below, unless otherwise specified, “part” refers to “part by mass.”

[Average particle diameter]

The average particle diameter of the polymer particles obtained in the examples and comparative examples was the average particle diameter when the laser diffraction type particle size distribution measuring device FPIA-3000S (manufactured by Spectris Co., Ltd.) was used and the number of effective analyzes was 30,000 ( The cumulative 50% particle diameter when based on volume) was measured and used as the average particle diameter.

[CV value]

The CV values of the polymer particles obtained in Examples and Comparative Examples were determined from the following formula.

CV value (%) = standard deviation of particle size distribution / average particle diameter × 100

[10% K value]

The 10% K value of the polymer particles obtained in Examples and Comparative Examples was measured using an ultra-micro indentation hardness tester ENT-NEXUS (manufactured by Elionix Co., Ltd.) at 25°C by attaching a 50 μm ϕ flat indenter to the tip of the tester. Using the attached microscope, select one polymer particle with a diameter of 3.0 μm, compress the polymer particle under the conditions of a maximum load of 50 mN and a load speed of 1.33 mN/sec, and the compressive load F when the particle diameter is deformed by 10% (N) was measured and obtained from the formula.

10% K value (N/mm ² )=(3/√2)·F·S ^-3/2 ·R ^-1/2

[F and S are the load value (N) and compressive displacement (mm) at 10% compressive deformation of the polymer particle, respectively, and R is the radius of the polymer particle (mm), and the polymer measured by the method described in the Examples It is half the average particle diameter of the particle.]

[Breaking point]

Using the same testing machine as the measurement of the above 10% K value, the particles were compressed, and if the particles broke before reaching the maximum load, the breaking point was considered “present.” The breaking point was taken as an indicator that the uncrosslinked polymers constituting the polymer particles were crosslinked by ring-opening polymerization between epoxy groups by a tertiary amine or imidazole-based post-addition catalyst. In addition, the notation “none” in the column of the breaking point in Tables 1 and 2 means that there is no corresponding data.

[IR(910cm) ^-One )]

A peak around 910 cm ^-1 was observed using infrared absorption spectroscopy (IR), and the disappearance of the peak confirmed that all epoxy groups in the polymer particles had reacted through addition reaction with an amino compound or ring-opening polymerization between epoxy groups. In addition, the symbol "-" in the IR (910 cm ^-1 ) column in Tables 1 and 2 means that there is no corresponding data, and "remaining" means that the peak remains, that is, the number of polymers constituting the polymer particles. This means that some epoxy groups exist as epoxy groups without undergoing addition reaction with an amine compound or without ring-opening polymerization.

Each evaluation result is shown in Table 1 and Table 2.

[Example 1]

<Process (1)>

(1st stage polymerization: production of monodisperse particles)

100 parts of methyl methacrylate (hereinafter also referred to as “MMA”) and 300 parts of ion-exchanged water were added to a four-neck flask with a capacity of 1 liter equipped with a thermometer and a nitrogen inlet tube, mixed and stirred, and further stirred under a nitrogen stream. While doing so, the temperature was raised to 80°C to obtain a mixed solution. 0.5 part of potassium persulfate was added to the heated mixture, and the mixture was reacted for 6 hours while maintaining the temperature at 80°C to obtain a dispersion of polymethyl methacrylate (PMMA) resin particles (A1).

The PMMA resin particles obtained by separating and drying from the dispersion (A1) were spherical monodisperse particles with an average particle diameter of 0.4 μm and a CV value of 3.5%. The solid content concentration in the dispersion (A1) was 24% by mass.

(2nd stage polymerization: seed polymerization)

In a flask with a capacity of 1 liter, 100 parts of methyl methacrylate and 1.0 parts of benzoyl peroxide as an initiator were added and dissolved to obtain a solution. 0.5 part of sodium dodecylbenzenesulfonate and 300 parts of ion-exchanged water were added to the solution and emulsified using a homomixer to obtain an emulsion.

Next, the PMMA resin particle dispersion (A1) was added to the emulsion so that the PMMA resin particle content was 6.4 parts.

After swelling this mixture for 1 hour at 50°C, water in which partially saponified polyvinyl alcohol was dissolved (40 parts in total of dispersion stabilizer and water) was added, reacted at 73°C for 1.5 hours, then reacted at 90°C for 1.5 hours, then cooled. By doing this, a dispersion (A2) of monodisperse seed particles with an average particle diameter of 1.0 μm and a CV value of 3.5% was obtained.

(3rd step polymerization: production of (meth)acrylic resin particles)

In a flask with a capacity of 1 liter, 66.3 parts of methyl methacrylate, 30 parts of glycidyl methacrylate (GMA), and 1.0 part of benzoyl peroxide as an initiator were added and dissolved to obtain a solution. 0.5 part of sodium dodecylbenzenesulfonate and 200 parts of ion-exchanged water were added to the solution and emulsified using a homomixer to obtain an emulsion.

Next, the dispersion liquid (A2) of the monodisperse seed particles was added to the emulsion so that the seed particle content was 3.7 parts.

After swelling this mixture for 1 hour at 50°C, water in which partially saponified polyvinyl alcohol was dissolved (40 parts in total of dispersion stabilizer and water) was added, reacted at 73°C for 1.5 hours and 90°C for 1.5 hours, and then cooled. , a dispersion of (meth)acrylic resin particles (A3) with an average particle diameter of 2.8 μm and a CV value of 5.2% was obtained.

<Process (2)>

(Contact of imidazole-based compounds and ring-opening polymerization between cyclic ether moieties)

To the dispersion (A3) obtained above, 1 part of 2-ethyl-4-methylimidazole (hereinafter also referred to as “2E4MZ”), which serves as an epoxy polymerization catalyst, is added to the parent particle based on 100 parts by mass of the particle solid content to form an imidazole-based The compound was brought into contact. Thereafter, by heating at 180°C for 1 hour, a dispersion (A4) containing a (meth)acrylic resin having a structure in which the cyclic ether portions of the (meth)acrylic resin particles were ring-opened polymerized with each other was obtained.

<Process (3)>

(powderization)

The dispersion (A4) is powdered by freeze-drying, and the powder is further pulverized with a mortar and a jet mill to produce (meth)acrylic resin particles having a structure in which the cyclic ether portions of the monodisperse seed particles are ring-opened polymerized with each other. Polymer particles containing were obtained.

[Examples 2 to 16, Comparative Examples 1 to 13]

Polymer particles were obtained in the same manner as in Example 1, except that the types and amounts of each component used were changed as shown in Tables 1 and 2.

[Comparative Example 14]

Since the boiling point of n-butylamine used as the amine-based curing agent is about 75°C, in the above <Step (2)>, n-butylamine is used instead of 2-ethyl-4-methylimidazole and heated. Polymer particles were obtained in the same manner as in Example 1, except that the temperature was set to 60°C.

The meaning of the symbol for each component in Tables 1 and 2 is as follows.

(seed)

·PMMA: Polymethyl methacrylate

(radical polymerizable monomer)

[(meth)acrylic acid ester (A)]

・GMA: Glycidyl methacrylate (Light Acrylate G, manufactured by Kyoeisha Chemical Co., Ltd.)

4HBAGE: 4-Hydroxybutyl acrylate glycidyl ether (manufactured by Mitsubishi Chemical Co., Ltd.)

[Monofunctional monomer]

MMA: Methyl methacrylate

・MAA: Methacrylic acid

[Bifunctional monomer]

EGDMA: Ethylene glycol dimethacrylate

[Trifunctional monomer]

・TMPTA: Trimethylolpropane triacrylate (Viscote #295, manufactured by Osaka Yuki Chemical Co., Ltd.)

[Tetrafunctional monomer]

PETA: Pentaerythritol tetraacrylate (M-305, Toagosei Co., Ltd.)

(Post-addition catalyst for cyclic ether ring-opening polymerization)

·DBU: 1,8-diazabicyclo[5.4.0]undeca-7-ene (manufactured by San-Apro Co., Ltd., molecular weight = 152.24)

SP-003: Polyethyleneimine (1-3 mixed amines (amine ratio 1: 45%)

Grade 2: 35% Grade 3: 20%), Eformin SP-003, manufactured by Nippon Shokubai Co., Ltd., number average molecular weight = 300)

2PZ-PW: 2-phenyl-1H-imidazole (Curesol 2PZ-PW, manufactured by Shikoku Chemical Seiko Co., Ltd., molecular weight = 144.17)

2MZA-PW: 2,4-diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1,3,5-triazine (Curesol 2MZA-PW, Shikoku Chemical Seiko Co., Ltd. Co., Ltd., molecular weight = 219.25)

・jER Cure IBMI12:1-isobutyl-2-methylimidazole (jER Cure IBMI12, manufactured by Mitsubishi Chemical Corporation, molecular weight = 138.21)

2E4MZ: 2-ethyl-4-methylimidazole (molecular weight = 110.16)

(Amine-based hardener)

jER Cure 113:4,4'-methylenebis(2-methylcyclohexanamine) (jER Cure 113, manufactured by Mitsubishi Chemical Corporation)

·Nissanamine M-14:1-amino-3-undecanoxy-propane (Nissanamine M-14, manufactured by Nichiyu Co., Ltd.)

·Butylamine: n-butylamine

In the column of “Crosslinked types of polymer particles” in Tables 1 and 2, “uncrosslinked” means polymer particles composed only of monofunctional monomers containing (meth)acrylic acid ester (A), and “crosslinked” means It means polymer particles composed of a monofunctional monomer containing (meth)acrylic acid ester (A), and a polymerizable monomer containing a polyfunctional monomer as a polymerizable monomer (B).

In the column “Post-addition catalyst for cyclic ether ring-opening polymerization” in Table 1, “H” means active hydrogen in the imidazole-based compound. In the case of "H x 0", it means that there is no active hydrogen in the imidazole-based compound, and in the case of "H

In the columns of “Post-addition catalyst for cyclic ether ring-opening polymerization” and “Amine-based curing agent” in Table 1 and Table 2, “NH ₂ ” refers to a primary imidazole-based compound or amine-based curing agent used in Examples and Comparative Examples. It means amino group. For example, in the case of “NH ₂ × 1”, it means that one primary amino group is present in the imidazole-based compound or amine-based curing agent.

As shown in Table 1, the polymer particles in each example had high hardness and excellent monodispersity.

In Example 11, the reason for the breaking point being “none” is that by using a post-addition catalyst that is an amino compound containing a mixture of primary to tertiary amino groups, primary and secondary amino groups with high reactivity to epoxy groups are used to form epoxy groups. It is thought that this is because the addition reaction proceeds only near the surface of the polymer particle, and the uncrosslinked polymer inside the particle remains as an uncrosslinked polymer without ring-opening polymerization between epoxy groups.

In Comparative Examples 9 to 11, it is thought that the reason why the breaking point is “present” is because a network polymer having a three-dimensional network structure is formed by using a large amount of monomers having more than one function.

In Comparative Example 12, the reason why IR (910 cm ^-1 ) is "remaining" is that the addition reaction of the primary amine to the epoxy group proceeds preferentially, but the tertiary amine produced by addition of the amino compound having a primary amino group It is thought that this is because amines have difficulty in carrying out catalytic reactions due to steric hindrance, and some epoxy groups remain without reacting. In addition, the amount of the amino compound having a primary amino group added in Comparative Example 12 was 0.04 equivalent to the epoxy group of GMA, which is the amount added when addition reaction with the epoxy group is usually performed using an amine-based curing agent (for example, the cyclic ether in the base particle) Since the molar ratio between the structure and the amine-based hardener is usually about 0.5 to 5), it is thought that some unreacted epoxy groups remain. Also, for the above-mentioned reasons, the polymer particle of Comparative Example 12 is thought to have a low 10% K value because it does not have a structure formed by ring-opening polymerization of ether moieties in GMA.

Nissanamine M-14, the amine-based curing agent used in Comparative Example 13, is a compound having a primary amino group. The n-butylamine of the amine-based curing agent used in Comparative Example 14 is a compound having a low molecular weight primary amino group. In Comparative Examples 13 and 14, as in Comparative Example 12, the tertiary amine produced by adding a compound having a primary amino group does not have a catalytic function to advance ring-opening polymerization between epoxy groups, and thus contributes to increasing the hardness of the polymer particles. I don't think I did it.

Claims (8)

A polymer particle comprising a (meth)acrylic resin that is formed by polymerizing (meth)acrylic acid ester (A) having a cyclic ether structure and has a structure formed by ring-opening polymerization of cyclic ether moieties in the cyclic ether structure. The polymer particle according to claim 1, wherein the (meth)acrylic resin further contains a structure derived from a polymerizable monomer (B) other than the (meth)acrylic acid ester (A) having the cyclic ether structure. The polymer particle according to claim 2, wherein the polymerizable monomer (B) is at least one compound selected from the group consisting of monomers having 1 to 4 (meth)acryloyl groups in one molecule. The polymer particle according to claim 1, wherein the (meth)acrylic acid ester (A) having the cyclic ether structure is a compound represented by the following formula (1).

[In formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, x represents an integer of 1 to 6, and Y represents a single bond or -O- CH ₂ - represents, and z represents an integer from 0 to 2.] The method of claim 1, which is formed by polymerizing (meth)acrylic acid ester (A) having the cyclic ether structure, and has a structure formed by adding an imidazole-based compound to a portion of the cyclic ether structure that is ring-opened. (meth)Polymer particles containing an acrylic resin. The polymer particle according to claim 1, wherein the polymer particle has a 10% K value of 3,000 to 7,000 N/mm ² . A method for producing the polymer particles of any one of claims 1 to 6, comprising:
A step (1) of radically polymerizing a polymerizable monomer component containing (meth)acrylic acid ester (A) having a cyclic ether structure to obtain a base particle containing a (meth)acrylic resin,
The parent particle is brought into contact with an imidazole compound or/and an amino compound having a tertiary amino group, ring-opening polymerizes the cyclic ether moieties in the cyclic ether structure, and the cyclic ether moieties undergo ring-opening polymerization to form a (meta) compound having a structure formed by ring-opening polymerization. ) Process (2) of obtaining polymer particles containing an acrylic resin,
A method for producing polymer particles, comprising the step (3) of powdering the polymer particles. The polymer particles according to any one of claims 1 to 6, which are used as conductive particles of an anisotropic conductive adhesive.