JP2023137308A - Heat crosslinkable particle and method for producing the same - Google Patents

Abstract

To provide heat crosslinkable particles which can suppress bleed-out and/or thermal decomposition of resin particles when a resin particle-containing resin compound is heated in molding, are excellent in bleed-out resistance and/or heat resistance, have a uniform particle diameter, and have narrow and sharp particle size distribution, and a method for producing the same.SOLUTION: Heat crosslinkable particles are obtained by compounding a polymer (C) obtained by polymerization of a polymerizable monomer component containing a vinyl-based monomer (A), and a polymer (D) obtained by polymerization of a polymerizable monomer component containing a vinyl-based monomer (B), wherein the vinyl-based monomer (A) is a vinyl-based monomer having at least one function group of an epoxy group and a group reacting with the epoxy group in a molecular structure, the vinyl-based monomer (B) is a vinyl-based monomer having at least one function group of an epoxy group and a group reacting with the epoxy group in a molecular structure, and the vinyl-based monomer (B) has at least a group reacting the group of the vinyl-based monomer (A) out of the epoxy group and the group reacting with the epoxy group.SELECTED DRAWING: None

Description

The present invention involves polymerizing a polymer (C) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (A) and a polymerizable monomer component containing a vinyl monomer (B). The present invention relates to heat-crosslinkable particles obtained by compounding the polymer (D) obtained by this method, and a method for producing the same.

Polymerization methods such as suspension polymerization, seed polymerization, emulsion polymerization, soap-free polymerization, and dispersion polymerization, and in particular, resin particles with submicron-order particle diameters obtained by polymerization methods such as seed polymerization and emulsion polymerization are light-diffusing. Used in a wide variety of applications, including anti-blocking agents for plates and various film membranes, various film modifiers, spacers between minute parts of various electronic devices, pore-forming agents for various battery components, and core particles of conductive fine particles responsible for electrical connections. It is used. Particularly in the field of optical films, it is necessary to consider the influence on optical properties such as haze and light transmittance, so resin fine particles are more preferably used than inorganic particles such as silica.
For example, resin particles obtained by polymerizing (meth)acrylic monomers, styrene monomers, etc. described in Patent Documents 1 and 2 have uniform particle sizes (narrow particle size distribution and sharp ), and the resulting film has excellent transparency, so it has been suitably used.

Japanese Unexamined Patent Publication No. 62-121701 Japanese Patent Application Publication No. 8-269146

As a method for producing a resin molded product such as an optical film containing resin particles, for example, a method of kneading and molding (extrusion molding, etc.) a resin constituting the resin molded product and a resin composition containing resin particles is used. It is being Along with this, resin particles are now required to have a high degree of resistance to heat during molding.
The resin particles described in Patent Document 1 are produced by seed polymerization, and non-crosslinked resin particles are used as the seed particles. Therefore, there was a fear that bleed-out and thermal decomposition of the seed particles could not be suppressed during processing at high temperatures.
Although the resin particles described in Patent Document 2 have excellent heat resistance, coloring of the particles cannot be suppressed due to the characteristics of the crosslinking agent, making them unsuitable for optical films. Furthermore, since non-crosslinked resin particles are used as seed particles, there is a fear that bleed-out or thermal decomposition of the seed particles cannot be suppressed during processing at high temperatures.

The problem to be solved by the present invention is to provide bleed-out resistance and/or to suppress bleed-out and/or thermal decomposition of resin particles when heating is performed during molding of a resin compound containing resin particles. It is an object of the present invention to provide heat-crosslinkable particles having excellent heat resistance, uniform particle size, and narrow and sharp particle size distribution, and a method for producing the same.
In the heat-crosslinkable particles of the present invention, a crosslinking reaction progresses inside the particles during processing at high temperatures, thereby suppressing bleed-out and/or thermal decomposition of non-crosslinked portions inside the heat-crosslinkable particles.

The present inventors conducted extensive studies to solve the above problems, and as a result, they discovered that the above problems could be solved by using specific heat-crosslinkable particles, and completed the present invention.
Specifically, the details are as follows.

[Item 1] A polymer (C) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (A) and a polymerizable monomer component containing a vinyl monomer (B). Heat-crosslinkable particles obtained by combining a polymer (D) obtained by polymerization,
The vinyl monomer (A) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.
Heat-crosslinkable particles.
[Item 2] The heat crosslinking according to Item 1, wherein the vinyl monomer (A) contains at least a group that reacts with an epoxy group, and the vinyl monomer (B) contains at least an epoxy group. particle.
[Item 3] The heat-crosslinking property according to Item 1, wherein the vinyl monomer (A) contains at least an epoxy group, and the vinyl monomer (B) contains at least a group that reacts with the epoxy group. particle.
[Item 4] The heat-crosslinkable particles according to any one of Items 1 to 3, wherein the vinyl monomer (A) is a (meth)acrylic monomer.
[Item 5] The heat-crosslinkable particles according to any one of Items 1 to 4, wherein the vinyl monomer (B) is a (meth)acrylic monomer.
[Item 6] The polymer (C) is a monofunctional (meth)acrylic monomer, a monofunctional styrene monomer, a polyfunctional (meth)acrylic monomer, and a polyfunctional styrenic monomer. The heat-crosslinkable particles according to any one of Items 1 to 5, which are obtained by polymerizing a polymerizable monomer component containing one or more types selected from the group consisting of:
[Item 7] The polymer (D) is obtained by polymerizing a polymerizable monomer component containing one or more selected from the group consisting of a monofunctional (meth)acrylic monomer and a monofunctional styrene monomer. The heat-crosslinkable particles according to any one of Items 1 to 6, which are obtained by
[Term 8] The following formula (1):
Heat crosslinkable particle sol content reduction rate = (Sol fraction after heat treatment of heat crosslinkable particles at 180°C for 30 minutes in an inert atmosphere) / (heat crosslinkable particle sol fraction) × 100 (1)
Item 8. The heat-crosslinkable particles according to any one of Items 1 to 7, wherein the heat-crosslinkable particle sol content reduction rate calculated from the equation is 50% or less.
[Item 9] Crosslinked particles obtained by thermally crosslinking the heat crosslinkable particles described in any one of Items 1 to 8,
The polymer (C) and the polymer (D) have the following formula (2):
-C(=O)-O-CH ₂ -CH(OH)-...(2)
Cross-linked particles that are bonded in a structure represented by.
[Item 10] The particle according to any one of Items 1 to 9, which is used as a resin compound additive.
[Item 11] The particles according to any one of Items 1 to 10, which are used as an anti-sticking agent for resin films.
[Item 12] The particle according to Item 11, wherein the resin film is a resin film for optical applications.
[Item 13] (i) Polymer (C) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (A), a polymerizable monomer component containing a vinyl monomer (B) mixed with body components and subjected to suspension polymerization, or
(ii) A polymer (D) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (B) is mixed with a polymerizable monomer component containing a vinyl monomer (A). and suspension polymerization,
A method for producing heat-crosslinkable particles, the method comprising:
The vinyl monomer (A) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.
Method for producing heat-crosslinkable particles.
[Item 14] A method for producing heat-crosslinkable particles in which seed particles are swollen with a polymerizable monomer component containing a vinyl monomer (A) and then polymerized, comprising:
The vinyl monomer (A) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The seed particles are obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (B),
The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.
Method for producing heat-crosslinkable particles.
[Item 15] A method for producing crosslinked particles, comprising heat-treating the heat-crosslinkable particles obtained by the method for producing heat-crosslinkable particles according to Item 13 or 14.

According to the present invention, the particles have excellent bleed-out resistance and/or heat resistance, which can suppress bleed-out and/or thermal decomposition of resin particles when heating is performed during molding of a resin compound containing resin particles. Provided are heat-crosslinkable particles having uniform diameters and a narrow and sharp particle size distribution, and a method for producing the same.

Hereinafter, the heat-crosslinkable particles, crosslinked particles, method for producing heat-crosslinkable particles, and method for producing crosslinked particles of the present invention will be described in detail. In the present specification, "(meth)acrylic" means acrylic and methacrylic, "(meth)acrylate" means acrylate and methacrylate, and "(meth)acryloyl" means acryloyl and methacryloyl, respectively.

[Heat-crosslinkable particles]
The heat-crosslinkable particles of the present invention include a polymer (C) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (A), and a polymerizable monomer component containing a vinyl monomer (B). Heat-crosslinkable particles obtained by combining a polymer (D) obtained by polymerizing monomer components,
The vinyl monomer (A) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.
They are heat-crosslinkable particles.

<Polymer (C)>
The polymer (C) constituting the heat-crosslinkable particles of the present invention is a polymerizable polymer containing a vinyl monomer (A) having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group. Obtained by polymerizing monomer components.

(Polymerizable monomer component containing vinyl monomer (A))
The polymerizable monomer component containing the vinyl monomer (A) is a vinyl monomer (A) having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group; It is composed of vinyl monomers (a) other than vinyl monomer (A) (hereinafter sometimes referred to as "other vinyl monomers (a)") depending on the vinyl monomer (A).
Here, the group that reacts with the epoxy group is not particularly limited. For example, one or more types selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group, a mercapto group, an isocyanate group, etc. can be mentioned. Among these, a carboxyl group or a hydroxyl group is preferred, and a carboxyl group is more preferred, from the viewpoint of reactivity, handleability, and the like.

Examples of the vinyl monomer having an epoxy group in its molecular structure that can become the vinyl monomer (A) include glycidyl (meth)acrylate, allyl glycidyl ether, 4-hydroxybutyl (meth)acrylate glycidyl ether, 1 selected from the group consisting of 1,2-epoxy-4-vinylcyclohexane, (3,4-epoxycyclohexyl)methyl (meth)acrylate, 4-vinylphenyl glycidyl ether, allyl glycidyl phthalate, allyl glycidyl hexahydrophthalate, etc. There are more than one species. From the viewpoint of versatility, ease of handling, etc., glycidyl (meth)acrylate and/or 4-hydroxybutyl (meth)acrylate glycidyl ether is preferred.

Examples of vinyl monomers having a carboxyl group in the molecular structure that can be used as vinyl monomer (A) include (meth)acrylic acid, 2-(meth)acryloyloxyethylsuccinic acid, and 2-methacryloyloxyethyl Phthalic acid, 2-methacryloyloxyethylhexahydrophthalic acid, 2-methacryloyloxyethylmaleic acid, 2-acryloyloxyethylhexahydrophthalic acid, 2-acryloyloxyethylsuccinic acid, 2-acryloyloxyethyl phthalic acid, o-vinyl Examples include one or more selected from the group consisting of benzoic acid, m-vinylbenzoic acid, p-vinylbenzoic acid, maleic acid, fumaric acid, maleic anhydride, and the like. From the viewpoint of versatility, ease of handling, etc., (meth)acrylic acid and 2-methacryloyloxyethylsuccinic acid are preferred.

Examples of vinyl monomers having a hydroxyl group in the molecular structure that can be used as vinyl monomer (A) include 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, o-vinylphenol, m-vinylphenol, p-vinylphenol, vinyl alcohol, allyl alcohol, glycerin monoallyl ether, neopentyl glycol monoallyl ether, о-Allylphenol, glycerin mono(meth)acrylate, diethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, polyethylene glycol polypropylene glycol mono(meth)acrylate, polyethylene glycol polytetramethylene Examples include one or more selected from the group consisting of glycol mono(meth)acrylate, polypropylene glycol polybutylene glycol mono(meth)acrylate, and the like.

Examples of vinyl monomers having an amino group in the molecular structure that can become vinyl monomer (A) include 2-aminoethyl (meth)acrylate, 2-aminopropyl (meth)acrylate, and 2-aminobutyl (meth)acrylate, 2-amino-3-phenoxypropyl (meth)acrylate, o-vinylaniline, m-vinylaniline, p-vinylaniline, allylamine, (meth)acrylamide, N-methyl (meth)acrylamide, N- One or more types selected from the group consisting of ethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, etc. can be mentioned.

Examples of vinyl monomers having a mercapto group in the molecular structure that can be used as vinyl monomer (A) include 2-mercaptoethyl (meth)acrylate, mercaptophenyl (meth)acrylate, and 2-mercaptoisopropyl (meth)acrylate. ) acrylate, 2-vinylbenzenethiol, 4-(mercaptomethyl)styrene, 4-mercaptostyrene, 4-vinylphenylmethanedithiol, 2-(vinyloxy)-3-butene-2-thiol, 2-(vinylthio)-3 -butene-2-thiol and the like.

Examples of the vinyl monomer having an isocyanate group in its molecular structure that can become the vinyl monomer (A) include 2-isocyanatoethyl (meth)acrylate, vinyl isocyanate, 4-vinylphenyl isocyanate, and 4-vinyl Phenylthioisocyanate, α,α-dimethyl-3-isopropenylbenzyl isocyanate, 1-methylethenyl isocyanate, 2-(vinyloxy)ethyl isocyanate, 2-vinylphenyl isocyanate, 2-isopropenyl phenyl isocyanate, 2-(1- Examples include one or more selected from the group consisting of methoxyvinyl) phenyl isocyanate, 2-(1-phenyl vinyl) phenyl isocyanate, 4-vinylbenzylisocyanate, and the like.

Other vinyl monomers (a) that are optionally included in the polymerizable monomer component containing the vinyl monomer (A) are not particularly limited. A vinyl monomer component containing at least one of a monofunctional (meth)acrylic monomer, a monofunctional styrene monomer, a polyfunctional (meth)acrylic monomer, and a polyfunctional styrene monomer It is more preferable that

Examples of monofunctional (meth)acrylic monomers include methyl (meth)acrylate (methyl methacrylate, methyl acrylate), ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylic acid. Isopropyl, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, Hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate , decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, Bonded to esters such as hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. An alicyclic structure such as (meth)acrylic acid alkyl ester in which the alkyl group has 1 to 20 carbon atoms, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and dicyclopentanyl (meth)acrylate is used as the ester moiety. One or more types selected from the group consisting of (meth)acrylic acid esters, etc., can be mentioned.

Among these, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, in which the alkyl group bonded to the ester has 1 to 10 carbon atoms; n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, (meth)acrylate ) hexyl acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, ( One or more selected from the group consisting of decyl meth)acrylate is preferred for general use, and in applications where heat resistance is particularly required, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and di(meth)acrylate are preferred. One or more types selected from the group consisting of cyclopentanyl can be mentioned.
These (meth)acrylic acid alkyl esters may be used alone or in combination of two or more.

Examples of monofunctional styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, ethylstyrene, t-butylstyrene, vinylnaphthalene, styrenesulfonic acid, and styrene. Examples include one or more selected from the group consisting of sulfonate salts (sodium styrene sulfonate, ammonium styrene sulfonate, etc.).
Among these, one or more selected from the group consisting of styrene, α-methylstyrene, and sodium styrene sulfonate are preferred.
These monofunctional styrene monomers may be used alone or in combination of two or more.

Examples of polyfunctional (meth)acrylic monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, decaethylene glycol di(meth)acrylate, and pentadecyl di(meth)acrylate. Ethylene glycol di(meth)acrylate, pentacontahecta ethylene glycol di(meth)acrylate, 1,3-butylene di(meth)acrylate, allyl(meth)acrylate (allyl methacrylate, allyl acrylate), trimethylolpropane tri(meth)acrylate ) acrylate, pentaerythritol tetraacrylate, and the like.
Among these, one or more selected from the group consisting of ethylene glycol di(meth)acrylate (ethylene glycol dimethacrylate) and allyl (meth)acrylate (allyl methacrylate) is preferred. These polyfunctional (meth)acrylic monomers may be used alone or in combination of two or more.

Examples of the polyfunctional styrenic monomer include one or more selected from the group consisting of divinylbenzene, divinylnaphthalene, divinyltoluene, and the like. These polyfunctional styrenic monomers may be used alone or in combination of two or more.

In addition to the above monomers, other vinyl monomers (a) include (meth)acrylamide monomers, (meth)acrylonitrile monomers, and halogenated vinyl monomers such as vinyl chloride. , carboxylic acid vinyl monomers such as vinyl acetate, olefin monomers such as ethylene, unsaturated imide monomers, silane coupling agents having vinyl groups, etc. are used. be able to.

The content of the vinyl monomer (A) in the polymerizable monomer component containing the vinyl monomer (A) is not particularly limited. When the total amount of polymerizable monomer components is 100% by mass, the amount of vinyl monomer (A) is, for example, 1% by mass or more, preferably 3% by mass or more, and, for example, 70% by mass or less, preferably 60% by mass. % or less.
When the vinyl monomer (A) is a vinyl monomer having an epoxy group in its molecular structure, the content thereof is, for example, 1% by mass or more, based on the total amount of polymerizable monomer components as 100% by mass, It is preferably 3% by mass or more, and can be, for example, 70% by mass or less, preferably 60% by mass or less.
When the vinyl monomer (A) is a vinyl monomer having a group that reacts with an epoxy group in its molecular structure, the content thereof is, for example, 1 It can be at least 3% by mass, preferably at least 3% by mass, and can be, for example, at most 50% by mass, preferably at most 40% by mass.

The vinyl monomer (A) reacts with a vinyl monomer having an epoxy group in its molecular structure and/or an epoxy group depending on the functional group in the molecular structure of the vinyl monomer (B). It can be a vinyl monomer having a group in its molecular structure. The vinyl monomer (A) has in its molecular structure at least a group that reacts with the group that the vinyl monomer (B) has among epoxy groups or groups that react with epoxy groups. be done.
For example, when the vinyl monomer (B) is a vinyl monomer that has an epoxy group in its molecular structure, the vinyl monomer (A) has a group that reacts with an epoxy group in its molecular structure. It is a vinyl monomer.
Further, for example, when using a vinyl monomer (B) having both an epoxy group and a group that reacts with the epoxy group in its molecular structure, or using a vinyl monomer having an epoxy group in its molecular structure, When using both a vinyl monomer and a vinyl monomer that has a group that reacts with an epoxy group in its molecular structure, the vinyl monomer (A) has an epoxy group and/or a group that reacts with an epoxy group. A vinyl monomer having either of these in its molecular structure can be used.

In one embodiment of the present invention, as the vinyl monomer (A), one or more vinyl monomers containing in the molecular structure at least a group that reacts with an epoxy group, As (B), it is preferable to use one or more vinyl monomers containing at least an epoxy group in its molecular structure.
In another embodiment of the present invention, one or more vinyl monomers containing at least an epoxy group in the molecular structure are used as the vinyl monomer (A), and the vinyl monomer (B ), it is preferable to use one or more vinyl monomers whose molecular structure includes at least a group that reacts with an epoxy group.
In one embodiment of the present invention, it is preferable to use one or more types of (meth)acrylic monomers as the vinyl monomer (A).

In the present invention, the polymer (C) includes, in addition to the vinyl monomer (A), a monofunctional (meth)acrylic monomer, a monofunctional styrene monomer, and a polyfunctional (meth)acrylic monomer. It is preferable that the monomer component be obtained by polymerizing a polymerizable monomer component containing one or more selected from the group consisting of styrene monomers and polyfunctional styrene monomers. In particular, in addition to the vinyl monomer (A), a polymerizable monomer component containing one or more selected from the group consisting of a polyfunctional (meth)acrylic monomer and a polyfunctional styrene monomer is used. Preferably, it is obtained by polymerization.

<Polymer (D)>
The polymer (D) constituting the heat-crosslinkable particles of the present invention is a polymerizable polymer containing a vinyl monomer (B) having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group. Obtained by polymerizing monomer components. The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.

(Polymerizable monomer component containing vinyl monomer (B))
The polymerizable monomer component containing the vinyl monomer (B) includes a vinyl monomer (B) having at least one functional group of an epoxy group or a group that reacts with an epoxy group in its molecular structure; It is composed of a vinyl monomer (b) other than the vinyl monomer (B) (hereinafter sometimes referred to as "other vinyl monomer (b)") that is included as necessary. The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among the epoxy groups or the groups that react with the epoxy groups.

The vinyl monomer (B) is selected from the vinyl monomers listed as the vinyl monomer (A) in the above "(Polymerizable monomer component containing vinyl monomer (A))". Use a vinyl monomer that has at least one selected type of epoxy group or a group that reacts with the group that the vinyl monomer (A) has among the epoxy groups or the groups that react with the epoxy group. I can do it.
Other vinyl monomers (b) include the vinyl monomers listed as other vinyl monomers (a) in "(Polymerizable monomer component containing vinyl monomer (A))" above. One or more types selected from monomers can be used.

The vinyl monomer (B) reacts with a vinyl monomer having an epoxy group in its molecular structure and/or an epoxy group depending on the functional group in the molecular structure of the vinyl monomer (A). It can be a vinyl monomer having a group in its molecular structure. The vinyl monomer (B) has in its molecular structure at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups. be done.
For example, when the vinyl monomer (A) is a vinyl monomer that has an epoxy group in its molecular structure, the vinyl monomer (B) has a group that reacts with an epoxy group in its molecular structure. It is a vinyl monomer.
For example, as the vinyl monomer (A), a vinyl monomer having both an epoxy group and a group that reacts with the epoxy group in its molecular structure may be used, or a vinyl monomer having an epoxy group in its molecular structure may be used. When using both a vinyl monomer and a vinyl monomer that has a group that reacts with an epoxy group in its molecular structure, the vinyl monomer (B) contains an epoxy group and/or a group that reacts with an epoxy group. A vinyl monomer having either of these in its molecular structure can be used.
In one embodiment of the present invention, it is preferable to use one or more types of (meth)acrylic monomers as the vinyl monomer (B).

In the present invention, in addition to the vinyl monomer (B), the polymer (D) is one or more selected from the group consisting of a monofunctional (meth)acrylic monomer and a monofunctional styrene monomer. It is preferable that it be obtained by polymerizing a polymerizable monomer component containing. In particular, polymerizable monomer components that do not contain polyfunctional monomers having two or more polymerizable ethylenically unsaturated groups, such as polyfunctional (meth)acrylic monomers and polyfunctional styrene monomers. It is preferable that it be obtained by polymerizing.

<Structure of heat-crosslinkable particles>
The heat-crosslinkable particles of the present invention are obtained by combining the polymer (C) and the polymer (D).
In the present invention, "composite" refers to a state in which the polymer (C) and the polymer (D) coexist in a single particle, and the coexistence state is not particularly limited.
Further, the means for compounding (compounding means) is not particularly limited. Examples include compositing by ionic bonds, covalent bonds, hydrogen bonds, van der Waals bonds, etc., compositing by electrostatic force, physical compositing by pressure bonding, and compositing using a binder such as a binder.

The blending ratio of polymer (C) and polymer (D) in the heat-crosslinkable particles is not particularly limited.
For example, 100 parts by mass or less of polymer (D), preferably 50 parts by mass or less, more preferably 25 parts by mass or less, per 1 part by mass of polymer (C), for example, 0.01 parts by mass of polymer (D). parts or more, preferably 0.02 parts by mass or more, more preferably 0.04 parts by mass or more. If the amount of polymer (D) is more than 100 parts by mass or less than 0.01 parts by mass per 1 part by mass of polymer (C), the crosslinking reaction will not proceed sufficiently when the target heat-crosslinkable particles are heated. There is a risk.

<Components contained in heat-crosslinkable particles>
The heat-crosslinkable particles of the present invention can contain various components in addition to the polymer (C) and the polymer (D). For example, antioxidants (hindered phenol-based, phosphorus-based, sulfur-based, amine-based, etc.), ultraviolet absorbers (hindered amine-based, etc.), thermal adhesion inhibitors (silica particles, etc.), polymers (C), and polymers. One or more types selected from the group consisting of polymers other than (D), colorants, fillers, etc. can be mentioned.

<Variation coefficient of volume average primary particle diameter/volume average primary particle diameter of heat-crosslinkable particles>
The volume average primary particle diameter of the heat-crosslinkable particles of the present invention is not particularly limited. It can be set as appropriate depending on the purpose and use. For example, it is 0.1 μm or more, preferably 0.15 μm or more, more preferably 0.2 μm or more, and can be, for example, 200 μm or less, preferably 100 μm or less, and more preferably 50 μm or less.
The coefficient of variation of the volume average primary particle diameter of the heat-crosslinkable particles of the present invention is not particularly limited. It can be set as appropriate depending on the purpose and use. For example, it can be set to 50% or less, preferably 40% or less, and more preferably 30% or less.

In the present invention, the volume average primary particle diameter and the coefficient of variation of the volume average primary particle diameter are determined by Coulter MultisizerTM3 (measurement device manufactured by Beckman Coulter) when the volume average primary particle diameter is 1 μm or more, and by laser diffraction/scattering method particle size distribution when it is less than 1 μm. It is determined by using a measuring device (“LS13320” manufactured by Beckman Coulter) and a universal liquid sample module.
When measuring with Coulter MultisizerTM3 (a measuring device manufactured by Beckman Coulter), the measurement shall be performed using an aperture calibrated in accordance with the MultisizerTM3 user's manual published by Beckman Coulter.
Note that the aperture used for measurement is appropriately selected depending on the size of the particles to be measured. Current (aperture current) and Gain are appropriately set depending on the selected aperture size. For example, if an aperture with a size of 50 μm is selected, Current (aperture current) is set to -800 and Gain (gain) is set to 4.

As a sample for measurement, 0.1 g of particles was placed in 10 ml of a 0.1% by mass nonionic surfactant aqueous solution using a touch mixer (manufactured by Yamato Scientific Co., Ltd., "TOUCHMIXERMT-31") and an ultrasonic cleaner (manufactured by Vervo Crea Co., Ltd.). , "ULTRASONIC CLEANER VS-150") to form a dispersion liquid. During the measurement, the inside of the beaker is stirred gently to prevent air bubbles from entering, and the measurement is terminated when 100,000 particles are measured. The volume average primary particle diameter of particles is the arithmetic mean of the volume-based particle size distribution of 100,000 particles.

The coefficient of variation (CV value) of the volume average primary particle diameter is calculated by the following formula (1):
Coefficient of variation of volume average primary particle diameter = (standard deviation of particle size distribution based on volume of particles ÷ volume average primary particle diameter of particles) × 100
Calculated by
When measuring the volume average primary particle diameter using a laser scattering/diffraction particle size distribution analyzer LS230 (manufactured by Beckman Coulter), water is used as the sample dispersion medium, and the refractive index of the sample is the refractive index of the polymer. Use. The volume average primary particle diameter here is a numerical value determined by an arithmetic mean. Further, the coefficient of variation is a numerical value obtained from the above equation (1), and represents the distribution width of data.

<Heat-crosslinkable particle sol fraction>
The heat-crosslinkable particle sol fraction can be determined by the following method.
The heat-crosslinkable particles are collected and precisely weighed to measure the mass (W1 g).
Thereafter, it is immersed in 100 parts by mass of toluene, stirred under reflux at 130° C. for 24 hours, and then cooled to obtain a thermally crosslinkable particle dispersion.
The obtained heat-crosslinkable particle dispersion is centrifuged at 18,000 rpm for 30 minutes using a centrifuge, the supernatant is removed, and the insoluble matter is collected. After washing the obtained insoluble matter, it is dried in a vacuum dryer at 60° C. for 12 hours, and the mass (W2 g) of the insoluble matter is measured.
Using the obtained masses (W1g) and (W2g), the following formula:
(W1-W2)/W1×100
From this, the heat-crosslinkable particle sol fraction (%) is determined.
The heat-crosslinkable particle sol fraction is not particularly limited. For example, it is 0.1% or more, preferably 1% or more, and 100% or less.

<Heat-crosslinkable particle sol content reduction rate>
The heat-crosslinkable particle sol fraction reduction rate is determined by the following formula using the heat-crosslinkable particle sol fraction and the crosslinked particle sol fraction:
Heat crosslinkable particle sol fraction reduction rate = (crosslinked particle sol fraction) / (heat crosslinkable particle sol fraction) x 100
You can ask for more.

The crosslinked particle sol fraction used in calculating the heat crosslinkable particle sol fraction reduction rate can be determined by the following method.
The heat-crosslinkable particles are heat-treated at 180° C. for 30 minutes in an inert atmosphere to obtain crosslinked particles. The inert atmosphere is not particularly limited as long as it is an oxygen-free atmosphere such as an inert gas atmosphere such as nitrogen, carbon dioxide, or a rare gas, or a vacuum atmosphere.
Collect the crosslinked particles, and determine the crosslinked particle sol fraction (%) in the same manner as (thermal crosslinkable particle sol fraction).

In the present invention, the heat-crosslinkable particle sol content reduction rate is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less. If the sol fraction of heat-crosslinkable particles exceeds 50%, heat-crosslinking will not proceed sufficiently, and when heating is performed during the molding process of a resin compound containing heat-crosslinkable particles, the heat-crosslinkable particles may bleed out and/or Thermal decomposition may occur.

[Method for producing heat-crosslinkable particles]
The method for producing heat-crosslinkable particles of the present invention (polymerization method) is not particularly limited as long as it is a known polymerization method. Examples include methods such as seed polymerization, suspension polymerization, emulsion polymerization, and dispersion polymerization.
In the present invention, a method of obtaining heat-crosslinkable particles by suspension polymerization or seed polymerization is preferably used.

<Seed polymerization>
In seed polymerization, polymer fine particles obtained by polymerizing an ethylenically unsaturated monomer (hereinafter sometimes referred to as "monomer") are used as seed particles, and the monomer is absorbed into the seed particles in a medium. , a method in which seed particles are swollen with a monomer and then the monomer is polymerized within the seed particles. In seed polymerization, by growing seed particles, resin particles having a larger particle size than the original seed particles can be obtained.

When the heat-crosslinkable particles of the present invention are produced by seed polymerization, the method of polymerizing monomers to obtain the seed particles used in the seed polymerization is not particularly limited. Dispersion polymerization, emulsion polymerization, soap-free emulsion polymerization (emulsion polymerization without using a surfactant as an emulsifier), seed polymerization, suspension polymerization, etc. can be used.
In order to obtain heat-crosslinkable particles by seed polymerization, it is necessary to first use seed particles having a substantially uniform particle size and to grow these seed particles substantially uniformly. The raw material, seed particles with a substantially uniform particle size, can be polymerized using a polymerization method such as soap-free emulsion polymerization (emulsion polymerization without using a surfactant), emulsion polymerization using a surfactant, dispersion polymerization, or seed polymerization. is preferred. The surfactant used in producing the seed particles is not particularly limited, but it is preferable to use one or more types of anionic surfactants.

During polymerization to obtain seed particles, a polymerization initiator can be used as necessary. The polymerization initiator is not particularly limited, and the polymerization initiators described below can be used. Preferably, one or more water-soluble radical polymerization initiators are used. The amount of the polymerization initiator used is preferably within the range of 0.1 to 2.0 parts by weight based on 100 parts by weight of the monomer used to obtain the seed particles. If it is less than 0.1 parts by mass, the reaction rate is slow and the efficiency is poor, and if it is more than 2.0 parts by mass, there is a risk that there will be too much polymerization initiator residue.
During polymerization to obtain seed particles, a molecular weight regulator can be used, if necessary, in order to adjust the weight average molecular weight of the obtained seed particles. Molecular weight modifiers include, but are not particularly limited to, mercaptans such as n-octylmercaptan and tert-dodecylmercaptan; α-methylstyrene dimer; terpenes such as γ-terpinene and dipentene; chloroform, carbon tetrachloride, etc. One or more types selected from the group consisting of halogenated hydrocarbons and the like can be used. By adjusting the amount of the molecular weight regulator used, the weight average molecular weight of the resulting seed particles can be adjusted.
The volume average particle diameter of the seed particles can be adjusted as appropriate depending on the average particle diameter of the heat-crosslinkable particles. Preferably, the range is 0.01 μm or more and 10 μm or less.

During seed polymerization, seed particles are added to an emulsion (hereinafter sometimes referred to as "emulsion") containing a monomer and an aqueous medium. An emulsion can be produced by a known method. For example, an emulsion can be obtained by adding a monomer to an aqueous medium and dispersing it using a microemulsifier such as a homogenizer, an ultrasonicator, or a nanomizer (registered trademark).
During seed polymerization, it is preferable to use one or more of the following various surfactants in a range of 0.3 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the monomer absorbed in the seed particles. If the amount of surfactant used is less than the above range, polymerization stability may decrease. Additionally, if the amount of surfactant used is greater than the above range, the amount of surfactant remaining in the heat-crosslinkable particles will be excessive, and foaming will occur when the heat-crosslinkable particles are dispersed in a medium. There is a risk.

During seed polymerization, the seed particles may be added to the emulsion in the form of particles, or may be added to the emulsion in the form of a dispersion in which the seed particles are dispersed in an aqueous medium. After adding the seed particles to the emulsion, the monomers are absorbed into the seed particles. This absorption can usually be carried out by stirring the emulsion at room temperature (about 25° C.) for 1 to 12 hours. Further, the emulsion may be heated to about 30 to 50°C in order to promote absorption of the monomer into the seed particles.

The seed particles swell by absorbing monomer. The mixing ratio of the monomer and the seed particles is such that the monomer is, for example, 1 part by mass or more, preferably 5 parts by mass or more, and 100 parts by mass or less, preferably 50 parts by mass or less, per 1 part by mass of the seed particles. It can be within. If the mixing ratio of the monomers is smaller than the above range, the increase in particle size due to polymerization will be small, resulting in a decrease in production efficiency. On the other hand, if the monomer mixing ratio is larger than the above range, the monomer will not be completely absorbed into the seed particles and will undergo emulsion polymerization on its own in the aqueous medium, producing heat-crosslinkable particles with an unintended and abnormal particle size. Sometimes. Note that the completion of absorption of the monomer into the seed particles can be determined by confirming the expansion of the particle diameter through observation with an optical microscope.

Next, a thermally crosslinkable particle dispersion is obtained by polymerizing the monomer absorbed into the seed particles. Furthermore, a heat-crosslinkable particle dispersion can be obtained by repeating the step of absorbing a monomer into seed particles and polymerizing it multiple times.
When polymerizing the monomer absorbed into the seed particles, a polymerization initiator may be added as necessary. After mixing the polymerization initiator with the monomer, the resulting mixture may be dispersed in an aqueous medium, or the polymerization initiator and monomer may be separately dispersed in an aqueous medium and then mixed. . The particle diameter of the monomer droplets present in the obtained emulsion is preferably smaller than the particle diameter of the seed particles, since the monomer is efficiently absorbed by the seed particles.
The polymerization initiator is not particularly limited, but the polymerization initiators described below can be used. Preferably, the polymerization initiator is used in an amount of 0 to 3 parts by weight based on 100 parts by weight of the monomer. Preferably, one or more water-soluble radical polymerization initiators are used.

The polymerization temperature for seed polymerization can be appropriately set depending on the type of monomer, the type of polymerization initiator used as needed, and the like. For example, the temperature may be 25°C or higher, preferably 50°C or higher, and, for example, 110°C or lower, preferably 100°C or lower.
The polymerization time of the seed polymerization can be appropriately set depending on the type of monomer, the type of polymerization initiator used as necessary, and the like. For example, it can be set to 1 to 12 hours.
Seed polymerization may be performed in an atmosphere of a gas inert to polymerization (eg, nitrogen, carbon dioxide, rare gas, etc.).
Seed polymerization is preferably carried out at elevated temperature after the monomer and optionally used polymerization initiator have been completely absorbed into the seed particles.
In seed polymerization, in order to improve the dispersion stability of heat-crosslinkable particles, a dispersant described below can be added to the polymerization reaction system as a dispersion stabilizer, if necessary. The dispersion stabilizer is not particularly limited, but it is preferable to use polyvinyl alcohol and/or polyvinylpyrrolidone. The amount of the dispersion stabilizer added is preferably in the range of 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the monomer.

During seed polymerization, nitrites such as sodium nitrite, sulfites, One or more water-soluble polymerization inhibitors selected from the group consisting of hydroquinones, ascorbic acids, water-soluble B vitamins, citric acid, polyphenols, etc. can be used. The amount of the polymerization inhibitor added can be, for example, in the range of 0.002 parts by mass or more and 0.2 parts by mass or less with respect to 100 parts by mass of the monomer.

<Suspension polymerization>
Suspension polymerization is a polymerization method in which a monomer and an aqueous medium are mechanically stirred to suspend and polymerize the monomer in the aqueous medium. Particles produced by suspension polymerization have a larger particle size and a broader particle size distribution than those produced by emulsion polymerization. On the other hand, it is also possible to obtain particles having a relatively sharp particle size distribution by using a fine emulsifier such as a homogenizer, an ultrasonicator, or a nanomizer (registered trademark).

When the heat-crosslinkable particles of the present invention are produced by suspension polymerization, the method of implementation is not particularly limited. For example, the polymer (D) is prepared in advance, and the polymer (D) is added to the monomer phase (polymerizable monomer component containing the vinyl monomer (A)) constituting the polymer (C). Heat-crosslinkable particles can be obtained by dissolving or dispersing and polymerizing this. Alternatively, for example, the polymer (C) may be prepared in advance, and the polymer (C) may be mixed with a monomer phase (a polymerizable monomer component containing a vinyl monomer (B)) constituting the polymer (D). ) and then polymerized to obtain heat-crosslinkable particles.
During suspension polymerization, the below-mentioned dispersant (inorganic dispersant, polymeric dispersant, etc.) and below-mentioned surfactant are added to the below-mentioned aqueous medium to create an emulsion in which monomers are suspended and dispersed. If necessary, the mixture is further suspended and finely dispersed to form an emulsion using an ultrasonic homogenizer or a high-pressure emulsifier, and then polymerized at a predetermined temperature to obtain heat-crosslinkable particles.

<Emulsion polymerization>
Emulsion polymerization is a polymerization method in which an aqueous medium, a monomer that is difficult to dissolve in this medium, and a surfactant (emulsifier) are mixed, and a polymerization initiator that is soluble in the aqueous medium is added thereto to perform polymerization. Emulsion polymerization is characterized by little variation in particle size of the resulting resin particles.
When the heat-crosslinkable particles of the present invention are produced by emulsion polymerization, the method of implementation is not particularly limited. For example, after preparing the polymer (D) in advance, mixing the polymer (D), an aqueous medium, a monomer constituting the polymer (C), and a surfactant described below, the aqueous medium Heat-crosslinkable particles can be obtained by adding a soluble polymerization initiator to the mixture and polymerizing the mixture.

<Dispersion polymerization>
Dispersion polymerization is a method in which monomers are dispersed in a polymerization solvent that may contain a dispersion stabilizer, a polymerization initiator is added, and the monomers are polymerized. In order to prevent particles from coalescing during polymerization, it is preferable to perform the polymerization under stirring by ultrasonic irradiation and/or stirring by a mechanical stirring device such as a magnetic stirrer. Dispersion polymerization is characterized in that the particle size can be easily controlled and resin particles can be easily obtained.
When the heat-crosslinkable particles of the present invention are produced by dispersion polymerization, the implementation method is not particularly limited. For example, the polymer (D) is prepared in advance, and the polymer (D), the monomers constituting the polymer (C), and the Heat-crosslinkable particles can be obtained by adding a polymerization initiator and polymerizing under stirring.

<Components used during polymerization>
In the method for producing heat-crosslinkable particles (polymerization method) of the present invention, a polymerization initiator, a surfactant (emulsifier), a dispersant, etc. can be used as necessary.

(Polymerization initiator)
The polymerization initiator used in producing the heat-crosslinkable particles of the present invention can be any known polymerization initiator and is not particularly limited.
As the polymerization initiator, radical polymerization initiators, particularly thermal polymerization initiators are preferable. For example, one or more polymerization initiators selected from the group consisting of persulfates (e.g., ammonium persulfate, potassium persulfate, sodium persulfate, etc.), hydrogen peroxide, organic peroxides, nitrile-azo compounds, etc. can give. For example, cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, dimethylbis(tert-butylperoxy)hexane, dimethylbis(tert-butylperoxy)hexane- 3. Bis(tert-butylperoxyisopropyl)benzene, bis(tert-butylperoxy)trimethylcyclohexane, butyl-bis(tert-butylperoxy)valerate, tert-butyl 2-ethylhexane peroxyate, dibenzoyl peroxide , paramenthane hydroperoxide and tert-butyl peroxybenzoate; 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2 '-Azobis(2-isopropylbutyronitrile), 2,2'-azobis(2,3-dimethylbutyronitrile), 2,2'-azobis(2,4-dimethylbutyronitrile), 2,2' -Azobis(2-methylcapronitrile), 2,2'-azobis(2,3,3-trimethylbutyronitrile), 2,2'-azobis(2,4,4-trimethylvaleronitrile), 2, 2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(4-ethoxy-2,4-dimethyl) valeronitrile), 2,2'-azobis(4-n-butoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2-(carbamoylazo)isobutyro Examples include one or more selected from the group consisting of nitrile, nitrile-azo compounds such as 4,4'-azobis(4-cyanopentanoic acid), and the like.
In addition, a polymerization initiator which is one or more of the above-mentioned persulfates and organic peroxides, sodium sulfoxylate formaldehyde, sodium bisulfite, ammonium bisulfite, sodium thiosulfate, ammonium thiosulfate, hydrogen peroxide, hydroxymethane A redox initiator in combination with one or more reducing agents selected from the group consisting of sodium sulfinate, L-ascorbic acid and its salts, cuprous salts, ferrous salts, etc. is used as a polymerization initiator. Good too.

Among these, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyro Nitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 4,4'-azobis(4-cyanopentanoic acid), cumene hydroperoxide , di-tert-butyl peroxide, dicumyl peroxide, benzoyl peroxide, and lauroyl peroxide.

The polymerization initiators may be used alone or in combination of two or more.
In the present invention, the amount of the polymerization initiator used varies depending on its type, but is, for example, 0.1 part by mass or more, preferably 0.2 parts by mass, based on 100 parts by mass of all the monomers used in the above polymerization. The amount may be at least 0.3 parts by mass, more preferably at least 0.3 parts by mass, and may be, for example, at most 5.0 parts by mass, preferably at most 3.0 parts by mass, and more preferably at most 2.0 parts by mass.

(surfactant)
As the surfactant used in producing the heat-crosslinkable particles of the present invention, known surfactants can be used and there are no particular limitations.
As the surfactant, one or more types selected from the group consisting of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants are used.

Examples of anionic surfactants include sodium oleate; fatty acid soaps such as castor oil potash soap; alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate; alkylnaphthalenes; Sulfonate; Alkanesulfonate; Dialkyl sulfosuccinate; Alkyl phosphate ester salt; Naphthalene sulfonic acid formalin condensate; Polyoxyethylene alkylphenyl ether sulfate; Polyoxyethylene sulfonated phenyl ether phosphate; Polyoxyethylene Alkyl sulfate salts, styrene sulfonic acid metal salts such as Spinomer (registered trademark) Nass (manufactured by Tosoh Finechem), and Eleminol (registered trademark) manufactured by Sanyo Chemical Industries, Ltd. such as JS-20, RS-3000, KH-10, KH-1025, KH-05, HS-10, HS-1025, BC-0515, BC-10, BC-1025, BC-20, BC- of Aqualon (registered trademark) manufactured by Ichi Kogyo Seiyaku Co., Ltd. 2020, AR-1025, AR-2025, S-120, S-180A, S-180, PD-104 of Latemul (registered trademark) manufactured by Kao Corporation, SR- of Adekarya Soap (registered trademark) manufactured by ADEKA 1025, SE-10N, and the like.

Examples of nonionic surfactants include polyoxyalkylene branched decyl ether, polyoxyethylene tridecyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene tridecyl ether, polyoxyethylene isodecyl ether, polyoxyalkylene lauryl ether, Polyoxyalkylene alkyl ether, polyether polyol, polyoxyethylene styrenated phenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene phenyl ether, polyoxyethylene polyoxypropylene glycol, polyoxyethylene lauryl ether, polyoxyethylene oleyl cetyl ether , polyoxyethylene glyceryl isostearate, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethylene- Oxypropylene block polymers, as well as those having reactivity, alkyl ether-based ones (commercially available products include ADEKA's Adekaria Soap ER-10, ER-20, ER-30, ER-40, Kao Latemul PD-420, PD-430, PD-450, etc.); alkylphenyl ether or alkyl phenyl ester type (commercially available products include Aqualon RN-10, RN-20, RN, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); (Meta) Examples include one or more selected from the group consisting of acrylate sulfate esters (commercially available products include, for example, RMA-564, RMA-568, and RMA-1114 manufactured by Nippon Nyukazai Co., Ltd.);

Examples of the cationic surfactant include one or more selected from the group consisting of alkylamine salts such as laurylamine acetate and stearylamine acetate; quaternary ammonium salts such as lauryltrimethylammonium chloride; and the like.

Examples of the zwitterionic surfactant include one or more selected from the group consisting of lauryl dimethylamine oxide, phosphate ester surfactants, phosphite ester surfactants, and the like.
These surfactants may be used alone or in combination of two or more. The type of surfactant to be used is appropriately selected and the amount used is appropriately adjusted in consideration of the particle diameter of the heat-crosslinkable particles to be obtained, the dispersion stability of monomers during polymerization, and the like.

In the present invention, the amount of surfactant used varies depending on its type, but is, for example, 0.01 part by mass or more, preferably 0.05 parts by mass, based on 100 parts by mass of all the monomers used in the above polymerization. The amount may be at least 0.1 parts by mass, more preferably at least 0.1 parts by mass, and may be, for example, at most 20.0 parts by mass, preferably at most 15.0 parts by mass, and more preferably at most 10.0 parts by mass.

(dispersant)
The dispersant used in producing the heat-crosslinkable particles of the present invention is not particularly limited, and any known dispersant can be used. A dispersant can be used to stabilize the dispersibility of monomer droplets and seed particles when an aqueous medium is used during polymerization.

Examples of the dispersant include organic dispersants such as partially saponified polyvinyl alcohol, polyacrylate, polyvinylpyrrolidone, carboxymethylcellulose, and methylcellulose; magnesium pyrophosphate, calcium pyrophosphate, calcium phosphate, calcium carbonate, magnesium phosphate, magnesium carbonate, One or more types selected from the group consisting of inorganic dispersants such as magnesium oxide; etc. can be mentioned. When using an inorganic dispersant, it is preferable to use a surfactant together.
These dispersants may be used alone or in combination of two or more. The type of dispersant is appropriately selected, and the amount used is appropriately adjusted, taking into consideration the particle diameter of the heat-crosslinkable particles to be obtained, the dispersion stability of the monomer during polymerization, and the like.

(polymerization medium)
The polymerization medium (polymerization solvent) used in producing the heat-crosslinkable particles of the present invention can be any known polymerization medium and is not particularly limited. It may be an aqueous medium or an organic medium (organic solvent).
In the present invention, it is preferable to use an aqueous medium. As the aqueous medium, for example, water alone or a mixture of water and a water-soluble organic solvent such as a lower alcohol (methanol, ethanol, isopropyl alcohol, etc.) can be used. Examples of water include one or more types selected from the group consisting of tap water, industrial water, ion exchange water, pure water, and the like. From the viewpoint of waste liquid treatment, water alone is preferable.

The amount of the aqueous medium used can be within the range of 200 to 2000 parts by weight, preferably within the range of 300 to 1500 parts by weight, based on 100 parts by weight of all monomers used in the polymerization. By setting the amount of the aqueous medium used to be at least the lower limit of the above range, it is possible to maintain the stability of monomer particles during polymerization and to suppress the generation of aggregates of heat-crosslinkable particles after polymerization. Productivity tends to be good by keeping the amount of the aqueous medium used below the upper limit.
In the present invention, the amount of the aqueous medium used varies depending on its type, but is, for example, 200 parts by mass or more, preferably 300 parts by mass or more, based on the total amount of 100 parts by mass of all monomers used in the above polymerization. For example, it can be in the range of 2000 parts by mass or less, preferably 1500 parts by mass or less.

<Cleaning, drying, crushing, and classification of heat-crosslinkable particles>
After completion of polymerization, the heat-crosslinkable particles can be washed, dried, crushed, classified, etc. as required depending on the intended use. For example, after completion of polymerization, a cake containing an aqueous medium (water-containing cake) is formed by a method such as suction filtration, centrifugation, or pressure separation, and if necessary, after a washing step with water and/or a solvent, it is dried in a drying step. If necessary, it can be isolated as a dry powder through a crushing step and a classification step.

The cleaning method in the cleaning step is not particularly limited. For example, the aqueous dispersion obtained after polymerization can be washed by centrifugal washing, cross-flow filtration, or the like. Further, after forming the water-containing cake, a step of immersing it in water and/or a solvent to remove liquid can be performed one or more times. Note that when a reactive surfactant (reactive emulsifier) is used as the surfactant (emulsifier), washing of the aqueous dispersion obtained after polymerization can be omitted.

The drying method in the drying step is not particularly limited. For example, a vacuum (reduced pressure) oven, a spray drying method using a spray dryer, a freeze drying method, a drying method in which the material is attached to a heated rotating drum such as a drum dryer, etc. can be used.

The classification method in the classification step is not particularly limited. For example, heat-crosslinkable particles or granules can be classified by known means using a sieve or the like. The classification step includes at least one of a first classification step of classifying the heat-crosslinkable particles obtained in the second polymerization step, and a classification step of classifying the heat-crosslinkable particles obtained in the crushing step. is preferred. Alternatively, a classification step may be used in which the aqueous dispersion obtained after polymerization is dispersed in an organic solvent such as alcohol, toluene, or ketone as necessary, and the dispersed state is passed through a sieve to remove coarse particles. .

<Applications of heat-crosslinkable particles>
The heat-crosslinkable particles of the present invention have excellent bleed-out resistance and/or heat resistance, which can suppress bleed-out and/or thermal decomposition of resin particles during thermoforming of a resin compound containing resin particles, and have a particle size of It is a heat-crosslinkable particle with a narrow and sharp particle size distribution.
Therefore, it can be suitably used as a resin compound additive, for example, various film modifiers.
In addition, the heat-crosslinkable particles of the present invention can be used as anti-sticking agents (anti-blocking agents) for resin films, particularly for optical applications such as light-diffusing films (light-diffusing plates), anti-glare films, anti-reflection films, and low-reflection films. It can be used as an anti-sticking agent for resin films.
Further, the heat-crosslinkable particles of the present invention can be added to a resin compound and used as a light diffusing agent, an anti-glare agent, an anti-reflection agent, a low-reflection agent, and the like.
The heat-crosslinkable particles of the present invention can be suitably used in the field of optical films where it is necessary to take into account the influence on optical properties such as haze and light transmittance.

The heat-crosslinkable particles of the present invention have excellent heat resistance and transparency, have a narrow particle size distribution, and have a small particle size. The influence on haze etc. can be suppressed. Furthermore, the occurrence of resin smear caused by heat load applied during resin compounding is suppressed, and there is little risk of deterioration of yield.
By using these heat-crosslinkable particles as an anti-sticking agent for resin films, especially for resin films for optical applications, it is possible to produce highly transparent optical members, such as optical films such as anti-glare films and light-diffusing films. This makes it possible to stably produce products such as light diffusers and light diffusers.

[Crosslinked particles and method for producing crosslinked particles]
The crosslinked particles of the present invention can be produced by heat-treating thermally crosslinkable particles to cause a crosslinking reaction inside the particles, thereby creating crosslinked particles in which the polymer (C) component and the polymer (D) component are bonded.
For example, the polymer (C) is a polymer (C) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (A) having an epoxy group in its molecular structure; When D) is a polymer (D) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (B) having a group that reacts with an epoxy group in its molecular structure, the crosslinked particles are , the polymer (C) and the polymer (D) are represented by the following formula (2):
-C(=O)-O-CH ₂ -CH(OH)-...(2)
It is connected in the structure represented by .

The heat treatment conditions for the heat-crosslinkable particles are not particularly limited. For example, it is preferable to perform the heat treatment in an inert atmosphere at a temperature of 135° C. or more and 300° C. or less for 5 to 180 minutes. If the heating time is less than 135° C. or less than 5 minutes, there is a possibility that the crosslinking reaction due to heating will not proceed sufficiently. If the temperature exceeds 300°C or exceeds 180 minutes, there is a risk that thermal decomposition of the polymer will proceed due to heating.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. In addition, unless otherwise specified, "parts" means "parts by mass."

[Production of polymer (D) or polymer (E)]
<Manufacture example 1>
270 parts of ion-exchanged water and 0.84 parts of sodium styrene sulfonate were charged into a polymerization vessel equipped with a stirrer, a thermometer, and a cooling mechanism, and the mixture was stirred and mixed to prepare an aqueous phase.
In a separate container, 60 parts of methyl methacrylate, 60 parts of glycidyl methacrylate, and 2.4 parts of 1-octanethiol were placed and stirred and mixed to prepare a monomer composition.
The monomer composition was charged into the aqueous phase in the polymerization vessel, the polymerization vessel was purged with nitrogen for 5 minutes, and then the temperature was raised to 80°C. When the temperature reached 80°C, 0.6 part of potassium persulfate was added to the ion A solution dissolved in 10 parts of exchanged water was added. Thereafter, nitrogen purging was performed again for 5 minutes, and the mixture was stirred and mixed at 80° C. for 5 hours to carry out an emulsion polymerization reaction. Thereafter, the temperature was raised to 100° C., maintained for 3 hours, and then cooled to obtain a polymer (D-1) in the form of a fine particle-containing slurry (solid content: 30% by mass). The volume average particle diameter of the obtained polymer (D-1) was 187 nm.

<Manufacture example 2>
Same as Production Example 1 except that 60 parts of methyl methacrylate, 60 parts of glycidyl methacrylate and 2.4 parts of 1-octanethiol were replaced with 102 parts of methyl methacrylate, 18 parts of glycidyl methacrylate and 2.4 parts of 1-octanethiol. A polymer (D-2) in the form of a fine particle-containing slurry (solid content 30% by mass) was obtained by the following procedure. The volume average particle diameter of the obtained polymer (D-2) was 186 nm.

<Manufacture example 3>
Same as Production Example 1 except that 60 parts of methyl methacrylate, 60 parts of glycidyl methacrylate, and 2.4 parts of 1-octanethiol were replaced with 102 parts of methyl methacrylate, 18 parts of methacrylic acid, and 2.4 parts of 1-octanethiol. A polymer (D-3) in the form of a fine particle-containing slurry (solid content 30% by mass) was obtained by the following procedure. The volume average particle diameter of the obtained polymer (D-3) was 183 nm.

<Manufacture example 4>
Except that 60 parts of methyl methacrylate, 60 parts of glycidyl methacrylate and 2.4 parts of 1-octanethiol were replaced with 102 parts of methyl methacrylate, 18 parts of 4-hydroxybutyl acrylate glycidyl ether and 2.4 parts of 1-octanethiol. Using the same procedure as in Production Example 1, a polymer (D-4) in the form of a fine particle-containing slurry (solid content 30% by mass) was obtained. The volume average particle diameter of the obtained polymer (D-4) was 193 nm.

<Manufacture example 5>
Fine particles were prepared in the same manner as in Production Example 1, except that 60 parts of methyl methacrylate, 60 parts of glycidyl methacrylate, and 2.4 parts of 1-octanethiol were replaced with 120 parts of methyl methacrylate and 2.4 parts of 1-octanethiol. A polymer (E) in the form of a slurry (solid content: 30% by mass) was obtained. The volume average particle diameter of the obtained polymer (E) was 178 nm.

<Manufacture example 6>
The polymer (D-1) obtained in Production Example 1 was placed in a vacuum oven, the water was evaporated to dryness, and the extract was crushed with a mixer to obtain a polymer (D-5). . The volume average particle diameter of the obtained polymer (D-5) was 8.2 μm.

[Production of heat-crosslinkable particles and crosslinked particles]
<Measurement method>
(Heat-crosslinkable particle sol fraction)
The heat-crosslinkable particles were sampled and precisely weighed to measure the mass (W1 g).
Thereafter, it was immersed in 100 parts by mass of toluene, stirred under reflux at 130° C. for 24 hours, and then cooled to obtain a heat-crosslinkable particle dispersion.
The obtained heat-crosslinkable particle dispersion was centrifuged at 18,000 rpm for 30 minutes using a centrifuge, the supernatant was removed, and the insoluble matter was collected. After washing the obtained insoluble matter, it was dried in a vacuum dryer at 60° C. for 12 hours, and the mass (W2g) of the insoluble matter was measured.
The following formula:
(W1-W2)/W1×100
From this, the heat-crosslinkable particle sol fraction (%) was determined.

(Crosslinked particle sol fraction)
The heat-crosslinkable particles were heat-treated at 180° C. for 30 minutes in the absence of oxygen to obtain crosslinked particles.
Crosslinked particles were collected, and the crosslinked particle sol fraction (%) was determined in the same manner as <heat crosslinkable particle sol fraction>.

(Heat-crosslinkable particle sol content reduction rate)
Using the heat crosslinkable particle sol fraction and the crosslinked particle sol fraction, the following formula:
(Crosslinked particle sol fraction)/(thermal crosslinkable particle sol fraction) x 100
From this, the reduction rate of heat-crosslinkable particle sol content was determined.

<Example 1>
(Manufacture of heat-crosslinkable particles)
In a polymerization vessel equipped with a stirring device, a thermometer, and a cooling mechanism, 200 parts of ion-exchanged water, 0.1 part of Rapizol (registered trademark) A-80 (manufactured by NOF Corporation), and Phosphanol LO-529 (Toho Chemical Co., Ltd.) were added. 0.1 part of Neugen EA-167 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 0.02 part of sodium nitrite were added and stirred and mixed to prepare an aqueous phase.
In a separate container, as the monomers constituting the polymer (C). 55 parts of methyl methacrylate, 30 parts of styrene, 5 parts of methacrylic acid, 10 parts of ethylene glycol dimethacrylate, 0.5 part of 2,2'-azobis(2,4-dimethylvaleronitrile) and 0.2 part of benzoyl peroxide. The mixture was added and stirred and mixed to prepare an oil phase.
The oil phase was put into the water phase in the polymerization vessel, and stirred and mixed for 10 minutes at 8000 rpm using a TK homomixer (manufactured by Primix) to obtain a monomer mixture. 47 parts (as solid content) of the polymer (D-1) obtained in Production Example 1 was added to this monomer mixture, and the mixture was stirred for 3 hours to swell.
After nitrogen purging for 5 minutes, the temperature was raised to 55°C, and the polymerization reaction was carried out by stirring at 55°C for 5 hours. After adding 0.06 parts of sulfamic acid into the polymerization vessel and stirring and mixing, the mixture was heated to 100°C, held at 100°C for 3 hours, and then cooled to obtain a slurry.

The obtained slurry was passed through a 400 mesh mesh to obtain a classified slurry containing heat-crosslinkable particles. The heat-crosslinkable particles obtained had a volume average primary particle diameter of 0.369 μm and a coefficient of variation (CV value) of the volume average primary particle diameter of 13.9%.
The classified thermally crosslinkable particle slurry was spray dried using a spray dryer (manufactured by Sakamoto Giken Co., Ltd., machine name: spray dryer, model: atomizer take-up method, model number: TRS-3WK) under the following equipment conditions. By doing so, a heat-crosslinkable particle granule was obtained.
The sol fraction of the obtained heat-crosslinkable particles (granules) was 15%.

-Spray dryer equipment conditions-
- Classified heat-crosslinkable particle-containing slurry supply rate: 25 mL/min
・Atomizer rotation speed: 12000rpm
・Air volume: 2m ³ /min
・Spray dryer inlet temperature (temperature of the slurry inlet containing resin particles provided in the spray dryer and into which the slurry containing heat-crosslinkable particles is sprayed and introduced): 150°C
・Spray dryer outlet temperature (powder outlet temperature at which the granules of heat-crosslinkable particles are discharged from the spray dryer): 70°C

(Manufacture of crosslinked particles)
The obtained granules of heat-crosslinkable particles were heat-treated at 180° C. for 30 minutes in a vacuum oven under an inert atmosphere to obtain crosslinked particles.
The sol fraction of the obtained crosslinked particles was 3%.

(Heat-crosslinkable particle sol content reduction rate)
The reduction rate of the heat-crosslinkable particle sol content was determined from the sol fraction of the heat-crosslinkable particles and the sol fraction of the heated particles, and the reduction rate of the heat-crosslinkable particle sol content was 20%.

<Examples 2 to 5, Comparative Examples 1 to 3>
Table 1 was prepared in the same manner as in Example 1, except that the monomer composition of polymer (C) and the type and amount of polymer (D) or polymer (E) added were as shown in Table 1. Heat-crosslinkable particles having the volume average particle diameter shown were obtained. Further, in the same manner as in Example 1, the sol fraction of the heat-crosslinkable particles, the sol fraction of the crosslinked particles, and the reduction rate of the sol content of the heat-crosslinkable particles were determined. The results are shown in Table 1.

<Example 6>
200 parts of ion-exchanged water, 10 parts of magnesium pyrophosphate, and 0.04 parts of sodium lauryl sulfate were charged into a polymerization vessel equipped with a stirring device, a thermometer, and a cooling mechanism, and the mixture was stirred and mixed to prepare an aqueous phase.
In a separate container, 40 parts of methyl methacrylate, 20 parts of butyl acrylate, 20 parts of styrene, 10 parts of ethylene glycol dimethacrylate, 1 part of 2-methacryloyloxyethylsuccinic acid, 2,2'-azobis(2,4- After 0.5 parts of dimethylvaleronitrile) and 0.2 parts of benzoyl peroxide were added and mixed with stirring, 5 parts of polymer (D-5) was further added and stirred and mixed to prepare an oil phase.
The oil phase was added to the water phase in the polymerization vessel, and stirred and mixed for 10 minutes at a stirring speed of 6500 rpm using a homomixer (manufactured by Primix, tabletop type, product name "Homomixer MARK II 2.5 type"). The phase was dispersed in the aqueous phase to obtain a dispersion. This dispersion was stirred at 60° C. for 6 hours to cause a suspension polymerization reaction, and the temperature was further raised to 100° C. and stirred for 3 hours to complete the polymerization.
Next, after cooling the suspension in the polymerization vessel to 30° C., hydrochloric acid was added to decompose the magnesium pyrophosphate.
Next, the suspension was suction-filtered, and the filtration residue was washed with ion-exchanged water, dehydrated, and dried in a vacuum oven set at 60°C for 20 hours to obtain heat-crosslinkable particles with a volume average particle diameter of 8.200 μm. I got it. Further, in the same manner as in Example 1, the sol fraction of the heat-crosslinkable particles, the sol fraction of the crosslinked particles, and the reduction rate of the sol content of the heat-crosslinkable particles were determined. The results are shown in Table 1.

The monomers constituting the polymer (C) in the table are as follows.
MMA: Methyl methacrylate BA: Butyl acrylate GMA: Glycidyl methacrylate St: Styrene EGDMA: Ethylene glycol dimethacrylate MAA: Methacrylic acid MAES: 2-methacryloyloxyethyl succinic acid

Claims (15)

A polymer (C) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (A) and a polymer obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (B). It is a heat-crosslinkable particle obtained by combining a polymer (D) that is
The vinyl monomer (A) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.
Heat-crosslinkable particles. The heat-crosslinkable particles according to claim 1, wherein the vinyl monomer (A) contains at least a group that reacts with an epoxy group, and the vinyl monomer (B) contains at least an epoxy group. The heat-crosslinkable particles according to claim 1, wherein the vinyl monomer (A) contains at least an epoxy group, and the vinyl monomer (B) contains at least a group that reacts with an epoxy group. The heat-crosslinkable particles according to any one of claims 1 to 3, wherein the vinyl monomer (A) is a (meth)acrylic monomer. The heat-crosslinkable particles according to any one of claims 1 to 4, wherein the vinyl monomer (B) is a (meth)acrylic monomer. The polymer (C) is selected from the group consisting of a monofunctional (meth)acrylic monomer, a monofunctional styrenic monomer, a polyfunctional (meth)acrylic monomer, and a polyfunctional styrenic monomer. The heat-crosslinkable particles according to any one of claims 1 to 5, which are obtained by polymerizing a polymerizable monomer component containing one or more of the following. The polymer (D) is obtained by polymerizing a polymerizable monomer component containing one or more selected from the group consisting of a monofunctional (meth)acrylic monomer and a monofunctional styrene monomer. The heat-crosslinkable particles according to any one of claims 1 to 6, which are The following formula (1):
Reduction rate of heat-crosslinkable particle sol content = (Sol fraction after heat treatment of heat-crosslinkable particles at 180°C for 30 minutes in an inert atmosphere) / (heat-crosslinkable particle sol fraction) × 100 (1)
The heat-crosslinkable particles according to any one of claims 1 to 7, wherein the heat-crosslinkable particles have a sol content reduction rate of 50% or less. A crosslinked particle obtained by thermally crosslinking the thermally crosslinkable particle according to any one of claims 1 to 8,
The polymer (C) and the polymer (D) have the following formula (2):
-C(=O)-O-CH ₂ -CH(OH)-...(2)
Cross-linked particles that are bonded in a structure represented by. Particles according to any one of claims 1 to 9, used as a resin compound additive. The particles according to any one of claims 1 to 10, which are used as an anti-sticking agent for resin films. Particles according to claim 11, wherein the resin film is a resin film for optical applications. (i) A polymer (C) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (A) is mixed with a polymerizable monomer component containing a vinyl monomer (B). and suspension polymerization, or
(ii) A polymer (D) obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (B) is mixed with a polymerizable monomer component containing a vinyl monomer (A). and suspension polymerization,
A method for producing heat-crosslinkable particles, the method comprising:
The vinyl monomer (A) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.
Method for producing heat-crosslinkable particles. A method for producing heat-crosslinkable particles in which seed particles are swollen with a polymerizable monomer component containing a vinyl monomer (A) and then polymerized, the method comprising:
The vinyl monomer (A) is a vinyl monomer having in its molecular structure at least one functional group of an epoxy group or a group that reacts with an epoxy group,
The seed particles are obtained by polymerizing a polymerizable monomer component containing a vinyl monomer (B),
The vinyl monomer (B) has at least a group that reacts with the group that the vinyl monomer (A) has among epoxy groups or groups that react with epoxy groups.
Method for producing heat-crosslinkable particles. A method for producing crosslinked particles, which comprises heat-treating the heat-crosslinkable particles obtained by the method for producing heat-crosslinkable particles according to claim 13 or 14.