JP2015218317A - Stress relaxation agent for curable resin, curable resin composition and molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stress relaxation agent for curable resins which has excellent thermal decomposition resistance and improves the stress relaxation performance of a resin composition and a molding when blended with a resin, a curable resin composition containing the stress relaxation agent and a molding of the curable resin composition.SOLUTION: A stress relaxation agent for curable resins consists of a graft copolymer (G) which is formed by grafting a polymer (A) containing a polyorganosiloxane (A1) and/or a poly(meth)acrylic acid alkyl ester (A2) with a vinyl polymer (B), and the vinyl polymer (B) contains a (meth)acrylate ester monomer (b1) unit and an aromatic vinyl monomer (b2) unit.

Description

  The present invention relates to a stress relaxation agent for a curable resin excellent in heat decomposition resistance, a curable resin composition containing the stress relaxation agent, and a molded body obtained by curing the resin composition. In particular, the present invention relates to a resin composition used for an electronic material such as a semiconductor, for example, a resin composition for a semiconductor sealing material and a stress relief for a curable resin useful for blending into a resin composition for an adhesive. The present invention relates to an agent, a curable resin composition containing the stress relaxation agent, and a molded product obtained by curing the resin composition.

  Resin molded bodies are manufactured according to various uses such as electric / electronic parts, automobile parts, and building materials. In these resin moldings, one or several kinds of resins and additives are used in order to develop the performance required according to the purpose. For example, in electrical / electronic parts such as transistors and ICs, resin sealing using a curable resin composition such as an epoxy resin as a mounting material has become mainstream. Resin sealing with this resin composition is excellent in mass productivity and can be produced at low cost, but the resin has a larger coefficient of linear expansion than that of semiconductor elements. It is a big issue.

  In order to reduce the elastic modulus of the curable resin composition and the molded product obtained by curing, and to improve the stress relaxation ability, rubber particles such as acrylic, butadiene, and silicone are blended as a stress relaxation agent. A method has been proposed. Among these, silicone rubber particles are excellent in stress relaxation ability and low elastic modulus (Patent Document 1).

  With recent changes in mounting technology and usage environment, stress relaxation agents are also required to have further improved thermal decomposition resistance. However, in the method of Patent Document 1, many of such rubber components impart stress relaxation ability to the epoxy resin, but the heat decomposition resistance is insufficient and the resin decomposes in the use environment, or the dispersibility is insufficient. For example, there has been a problem that when added to an epoxy resin for sealing, poor dispersion occurs and cracks occur due to thermal stress.

JP 2010-7045 A

  The present invention has been made in order to solve the problems of the prior art as described above, has an excellent heat decomposability, and is blended with a resin. It aims at providing the stress relaxation agent for curable resins which improves curable resin, the curable resin composition containing this stress relaxation agent, and its molded object.

That is, the present invention is characterized by the following.
[1] From the graft copolymer (G) obtained by grafting the vinyl polymer (B) to the polymer (A) containing the polyorganosiloxane (A1) and / or the poly (meth) acrylic acid alkyl ester (A2). A stress relieving agent for a curable resin comprising:
The stress relaxation agent for curable resin in which a vinyl polymer (B) contains a (meth) acrylic acid ester monomer (b1) unit and an aromatic vinyl monomer (b2) unit.
[2] The above-mentioned vinyl polymer (B) contains 5 to 95% by mass of the (meth) acrylic acid ester monomer (b1) unit (provided that the vinyl polymer (B) is 100% by mass). 1] The stress relaxation agent for curable resins.
[3] The above [1] or [2] wherein the polymer (A) contains 0.1 to 99.9% by mass of the polyorganosiloxane (A1) (provided that the polymer (A) is 100% by mass). ] The stress relaxation agent for curable resins of description.
[4] The above [1], wherein the vinyl polymer (B) contains 0.5 to 10% by mass of the crosslinkable monomer (b4) unit (provided that the vinyl polymer (B) is 100% by mass). The stress relaxation agent for curable resins according to any one of to [3].
[5] A curable resin composition comprising the stress relaxation agent for curable resin according to any one of [1] to [4] and a curable resin.
[6] A molded product obtained by curing the curable resin composition according to [5].
[7] A semiconductor sealing material using the curable resin composition according to [5].
[8] An adhesive using the curable resin composition according to [5].
[9] A prepreg, a laminate, and a printed wiring board using the curable resin composition according to [5].

  By blending the stress relaxation agent of the present invention in the resin, the stress relaxation ability of the resulting resin composition and molded article can be improved while maintaining the thermal decomposition resistance of the resin. The curable resin composition and molded article of the present invention are useful for semiconductor sealing applications and adhesive applications.

Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited only to these embodiments.
In the present invention, (meth) acryl means acryl or methacryl.

  The stress relieving agent of the present invention is a graft copolymer obtained by grafting a vinyl polymer (B) to a polymer (A) containing a polyorganosiloxane (A1) and / or a poly (meth) acrylic acid alkyl ester (A2). It consists of a coalescence (G), and a vinyl polymer (B) contains a (meth) acrylic acid ester monomer (b1) unit and an aromatic vinyl monomer (b2) unit.

[Polyorganosiloxane (A1)]
The polyorganosiloxane (A1) is a polymer containing an organosiloxane unit as a constituent unit, and preferably has a structure in which cyclic organosiloxanes are linked via a graft crossing agent.
The polyorganosiloxane (A1) is an organosiloxane, a graft cross-linking agent for polyorganosiloxane (hereinafter referred to as “siloxane cross-linking agent”), and, if necessary, a cross-linking agent for polyorganosiloxane (hereinafter referred to as “siloxane cross-linking agent”). ) And, if necessary, it is obtained by emulsion polymerization of an organosiloxane mixture comprising a siloxane oligomer having a terminal blocking group.

  As the organosiloxane, either a chain organosiloxane or a cyclic organosiloxane can be used, but a cyclic organosiloxane is preferred because it has high polymerization stability and a high polymerization rate. The cyclic organosiloxane is preferably a cyclic organosiloxane having 3 or more members, more preferably a 3 to 6 members. Examples of the cyclic organosiloxane include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, and octaphenylcyclohexane. Tetrasiloxane is mentioned. These may be used alone or in combination of two or more.

As the siloxane crossing agent, a vinyl monomer such as a monomer or a vinyl monomer (b) that forms a poly (meth) acrylic acid alkyl ester (A2) by binding with the organosiloxane via a siloxane bond; Those capable of forming a bond are preferred. Considering the reactivity with organosiloxane, an alkoxysilane compound having a vinyl group is preferred.
By using a siloxane crossing agent, a polyorganosiloxane having a functional group polymerizable with the vinyl copolymer can be obtained. The polyorganosiloxane has a functional group polymerizable with the vinyl monomer, so that the polyorganosiloxane is chemically bonded to the poly (meth) acrylic acid alkyl ester (A2) and the vinyl monomer (b). Can do.

  Examples of the siloxane crossing agent include siloxane represented by the formula (1).

In formula (1), R ¹ represents a methyl group, an ethyl group, a propyl group, or a phenyl group. R ² represents an organic group in the alkoxyl group, and examples thereof include a methyl group, an ethyl group, a propyl group, and a phenyl group. n represents 0, 1 or 2. R represents any group represented by formulas (2) to (5).

In these formulas, R ³ and R ⁴ each represent hydrogen or a methyl group, and p represents an integer of 1 to 6.

  A methacryloyloxyalkyl group can be mentioned as a functional group represented by Formula (2). Examples of the siloxane having this group include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxy. Mention may be made of propylethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, δ-methacryloyloxybutyldiethoxymethylsilane.

  Examples of the functional group represented by the formula (3) include a vinylphenyl group. Examples of the siloxane having this group include vinylphenylethyldimethoxysilane.

  Examples of the siloxane having a functional group represented by the formula (4) include vinyltrimethoxysilane and vinyltriethoxysilane.

  Examples of the functional group represented by the formula (5) include a mercaptoalkyl group. Examples of the siloxane having this group include γ-mercaptopropyldimethoxymethylsilane, γ-mercaptopropylmethoxydimethylsilane, γ-mercaptopropyldiethoxymethylsilane, γ-mercaptopropylethoxydimethylsilane, and γ-mercaptopropyltrimethoxysilane. be able to.

  These siloxane crossing agents may be used alone or in combination of two or more.

  As the siloxane crosslinking agent, those having 3 or 4 functional groups capable of bonding to the organosiloxane are preferable. Examples of the siloxane crosslinking agent include trialkoxyalkylsilanes such as trimethoxymethylsilane; trialkoxyarylsilanes such as triethoxyphenylsilane; tetramethoxysilanes, tetraethoxysilanes, tetran-propoxysilanes, tetrabutoxysilanes, and the like. An alkoxysilane is mentioned. These may be used alone or in combination of two or more. Among these, tetraalkoxysilane is preferable, and tetraethoxysilane is more preferable.

  The siloxane oligomer having a terminal blocking group means a siloxane oligomer having an alkyl group or the like at the terminal of the organosiloxane oligomer and stopping the polymerization of the polyorganosiloxane.

  Examples of the siloxane oligomer having a terminal blocking group include hexamethyldisiloxane, 1,3-bis (3-glycidoxypropyl) tetramethyldisiloxane, and 1,3-bis (3-aminopropyl) tetramethyldisiloxane. And methoxytrimethylsilane.

  The content of organosiloxane in the organosiloxane mixture (100% by mass) is preferably 60 to 99.9% by mass, and more preferably 70 to 99.9% by mass. The content of the siloxane crossing agent in the organosiloxane mixture (100% by mass) is preferably in the range of 0.1 to 10% by mass. The content of the siloxane crosslinking agent in the organosiloxane mixture (100% by mass) is preferably in the range of 0 to 30% by mass. The content of the siloxane oligomer having a terminal blocking group in the organosiloxane mixture (100% by mass) is preferably 0 to 10% by mass.

[Production method of polyorganosiloxane]
There is no restriction | limiting in particular as a manufacturing method of polyorganosiloxane, For example, the following manufacturing methods are employable.
First, an emulsion is prepared by emulsifying an organosiloxane mixture containing an organosiloxane and a siloxane cross-linking agent, if necessary, a siloxane cross-linking agent, and if necessary, a siloxane oligomer having a terminal blocking group, with an emulsifier and water. And polymerized at a high temperature, and then neutralized with an alkaline substance to obtain a polyorganosiloxane latex.

  In this production method, emulsion preparation methods include a method using a homomixer that makes fine particles by shearing force by high-speed rotation, a method that mixes by high-speed agitation using a homogenizer that makes fine particles by jet output from a high-pressure generator, etc. Is mentioned. Among these, the method using a homogenizer is a preferable method because the particle size distribution of the polyorganosiloxane latex becomes narrow.

  As a method of mixing the acid catalyst during polymerization, a method of adding and mixing together with an organosiloxane mixture, an emulsifier and water, a method of adding an acid catalyst aqueous solution all together in an emulsion of an organosiloxane mixture, an organosiloxane Examples include a method in which the emulsion of the mixture is dropped into a high-temperature acid aqueous solution at a constant speed and mixed, but since the particle diameter of the polyorganosiloxane is easy to control, the emulsion of the organosiloxane mixture is kept at a high temperature, and then A method in which the acid catalyst aqueous solution is added all at once is preferred.

  The polymerization temperature is preferably 50 ° C. or higher, and more preferably 70 ° C. or higher. The polymerization time is usually 2 hours or longer, preferably 5 hours or longer when the acid catalyst aqueous solution is added all at once to the emulsion of the organosiloxane mixture for polymerization.

  Furthermore, since the cross-linking reaction between silanols proceeds at a temperature of 30 ° C. or lower, the temperature can be maintained at a temperature of 30 ° C. or lower for about 5 to 100 hours in order to increase the cross-linking density of the polyorganosiloxane.

  The polymerization reaction of the polyorganosiloxane can be terminated by neutralizing the latex to pH 6-8 with an alkaline substance such as sodium hydroxide, potassium hydroxide, or aqueous ammonia solution.

  The emulsifier used in the above production method is not particularly limited as long as the organosiloxane can be emulsified, but an anionic emulsifier or a nonionic emulsifier is preferable. Examples of the anionic emulsifier include sodium alkylbenzene sulfonate, sodium alkyldiphenyl ether disulfonate, sodium alkyl sulfate, sodium polyoxyethylene alkyl sulfate, and sodium polyoxyethylene nonyl phenyl ether sulfate.

Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene tribenzylphenyl ether, and polyoxyethylene polyoxypropylene glycol. .
These emulsifiers may be used individually by 1 type, and may use 2 or more types together.

  It is preferable that the usage-amount of an emulsifier is 0.05-12 mass parts with respect to 100 mass parts of organosiloxane mixtures. It is possible to adjust to a desired particle size depending on the amount of emulsifier used.

  Examples of the acid catalyst used for polymerization of polyorganosiloxane include sulfonic acids such as aliphatic sulfonic acid, aliphatic substituted benzenesulfonic acid, and aliphatic substituted naphthalenesulfonic acid, and mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid. These acid catalysts are used alone or in combination of two or more. Among these, when mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid are used, the particle size distribution of the polyorganosiloxane latex can be narrowed, and further, the appearance of the molded product is poor due to the emulsifier component in the polyorganosiloxane latex. Is preferable in that it can be reduced.

  The volume average particle diameter of the polyorganosiloxane latex is preferably 10 nm to 1000 nm. Furthermore, it is more preferable that it is 10 nm-500 nm.

  The volume average particle size / number average particle size (Dv / Dn) of the polyorganosiloxane latex is preferably 1.0 to 1.7.

Values measured by the following methods can be adopted as the volume average particle diameter and number average particle diameter of the polyorganosiloxane latex.
The particle size is measured using a laser diffraction particle size distribution measuring device (SALD-7100, manufactured by Shimadzu Corporation).

[Poly (meth) acrylic acid alkyl ester (A2)]
The poly (meth) acrylic acid alkyl ester (A2) is obtained by polymerizing the vinyl monomer (a2). The vinyl monomer (a2) contains a (meth) acrylic acid alkyl ester (a2-1) and an acrylic crossover agent (a2-2), and optionally contains a crosslinkable monomer (a2-3). The vinyl monomer (a2-4) can be used in combination.

The poly (meth) acrylic acid alkyl ester (A2) preferably has a glass transition temperature (Tg) represented by the formula of FOX (formula (6)) of −80 to 10 ° C., and −70 to −10. More preferably, it is ° C. Thereby, the elasticity modulus of the obtained molded object falls and stress relaxation ability improves.
1 / (273 + Tg) = Σ (wi / (273 + Tgi)) (6)
In the formula, Tg is the glass transition temperature (° C.) of the copolymer, wi is the mass fraction of monomer i, and Tgi is the glass transition temperature (° C.) of the homopolymer obtained by polymerizing monomer i. is there.
The numerical value described in POLYMER HANDBOOK Volume 1 (WILEY-INTERSCIENCE) is used for the numerical value of Tg of the homopolymer.

Examples of the (meth) acrylic acid alkyl ester (a2-1) include acrylic acid such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and octyl acrylate. Alkyl ester; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, and the like. These may be used alone or in combination of two or more.
Since the poly (meth) acrylic acid alkyl ester (A2) having a low glass transition temperature is obtained, the content of the (meth) acrylic acid alkyl ester (a2-1) is determined by the vinyl monomer (a2) (100% by mass). ) Is preferably 70 to 99.9 mass%, more preferably 90 to 99.9 mass%.
Considering the emulsion polymerization property and the glass transition temperature of the resulting polymer, it is preferable to contain butyl acrylate or 2-ethylhexyl acrylate. Moreover, since it is excellent in thermal decomposition resistance, it is more preferable to contain butyl acrylate.

  The acrylic crossover agent (a2-2) is a polyfunctional monomer having two or more polymerizable unsaturated bonds having different reactivities. By having a group having different reactivity, it is incorporated into the polymer (A) in a state where the unsaturated group is preserved when polymerized together with other components, and the monomer (b) is polymerized at the time of polymerization. Combined with (b) to allow formation of a graft copolymer. Examples thereof include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate, and the like can be used alone or in combination of two or more.

Since the acrylic crossover agent (a2-2) also has a function as a crosslinking agent, it can also serve as a crosslinking agent.
The content of the acrylic crossover agent (a2-2) is preferably 0.01 to 10% by mass in the vinyl monomer (a2) (100% by mass). If the content of the acrylic crossover agent (a2-2) is 0.01% by mass or more, the poly (meth) acrylic acid alkyl ester (A2) has a sufficient graft polymerization starting point, and if it is 10% by mass or less. For example, the rubber elasticity of the poly (meth) acrylic acid alkyl ester (A2) can be maintained.

The crosslinkable monomer (a2-3) is a polyfunctional monomer having two or more polymerizable unsaturated bonds having the same reactivity. For example, divinylbenzene, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol diacrylate, triallyl trimelliate These can be used alone or in combination of two or more.
In the vinyl monomer (a2) (100% by mass), the content of the crosslinkable monomer (a2-3) is preferably 0 to 10% by mass. If the content of the crosslinkable monomer (a2-3) is 10% by mass or less, the rubber elasticity of the poly (meth) acrylic acid alkyl ester (A2) can be maintained.

  Examples of the optional vinyl monomer (a2-4) include aromatic vinyl monomers such as styrene and α-methylstyrene; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile. It is preferable that arbitrary vinyl monomer (a2-4) content rate is 0-20 mass% in vinyl monomer (a2) (100 mass%).

[Polymer (A)]
The polymer (A) is a rubbery polymer containing the polyorganosiloxane (A1) and / or the poly (meth) acrylic acid alkyl ester (A2).

  The content of the polyorganosiloxane (A1) is 0 to 100% by mass (provided that the polymer (A) is 100% by mass), preferably 0.1 to 100% by mass, It is more preferably ˜99.9% by mass, and particularly preferably 5 to 90% by mass. When the content of the polyorganosiloxane (A1) is 0.1 to 99.9% by mass, a resin composition having a lower elastic modulus and higher stress relaxation ability can be obtained.

[Production Method of Polymer (A)]
There is no restriction | limiting in particular as a manufacturing method of a polymer (A), For example, although it can manufacture by an emulsion polymerization method, a suspension polymerization method, and a fine suspension polymerization method, it is preferable to use an emulsion polymerization method. Among these, a method of obtaining a latex of the polymer (A) by emulsion polymerization of the (meth) acrylic acid alkyl ester (a2) in the presence of a polyorganosiloxane latex is particularly preferable.

  As a method for polymerizing (meth) acrylic acid alkyl ester (a2-1) in the presence of polyorganosiloxane latex, first, (meth) acrylic acid alkyl ester (a2-1) is added to polyorganosiloxane latex. Then, after impregnating in the polyorganosiloxane, polymerization is carried out by applying a known radical polymerization initiator. As a method of adding to this production method, there are a method of adding the whole amount to the polyorganosiloxane latex at once, and a method of adding dropwise to the polyorganosiloxane latex at a constant rate.

  In producing the latex of the polymer (A), an emulsifier can be added to stabilize the latex and control the particle diameter of the polymer (A). The emulsifier is not particularly limited, and an anionic emulsifier and a nonionic emulsifier are preferable.

  Examples of the anionic emulsifier include sodium alkylbenzene sulfonate, sodium alkyldiphenyl ether disulfonate, sodium alkyl sulfate, polyoxyethylene alkyl sodium sulfate, sodium polyoxyethylene nonyl phenyl ether sulfate, sodium sarcosine, fatty acid potassium, fatty acid sodium, alkenyl. Examples include dipotassium succinate, rosin acid soap, polyoxyethylene alkyl sodium phosphate, and polyoxyethylene alkyl calcium phosphate.

  Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzyl phenyl ether. These emulsifiers can be used alone or in combination of two or more.

  As the radical polymerization initiator used for the production of the poly (meth) acrylic acid alkyl ester (A2), an azo initiator, a peroxide, and a redox initiator in which a peroxide and an oxidizing agent / reducing agent are combined are used. . These can be used alone or in combination of two or more.

  Examples of the azo initiator include oil-soluble azo initiators such as 2,2′-azobisisobutyronitrile and dimethyl 2,2′-azobis (2-methylpropionate), 4,4′- Azobis (4-cyanovaleric acid), 2,2′-azobis [N- (2-carboxymethyl) -2-methylpropionamidine] hydrate, 2,2′-azobis- (N, N′-di) And water-soluble azo initiators such as methyleneisobutylamidine) dihydrochloride and 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride. These can be used alone or in combination of two or more.

  Examples of the peroxide include inorganic peroxides such as hydrogen peroxide, potassium persulfate, and ammonium persulfate, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, Succinic acid peroxide, t-butylperoxyneodecanoate, t-butylperoxyneoheptanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2- Organic peroxides such as ethyl hexanoate and t-butyl peroxy-2-ethyl hexanoate can be mentioned. These peroxides can be used alone or in combination of two or more.

When a peroxide is used as a redox initiator in combination with a reducing agent, the above peroxide, a reducing agent such as sodium formaldehyde sulfoxylate, L-ascorbic acid, fructose, dextrose, sorbose, inositol, and sulfuric acid It is preferable to use a combination of monoiron and ethylenediaminetetraacetic acid disodium salt.
These reducing agents can be used alone or in combination of two or more.

  As the usage-amount of a radical polymerization initiator, when using an azo initiator, it is preferable that it is 0.01-1 mass part with respect to 100 mass parts of graft copolymers (G).

  In the case of a redox initiator, the amount of peroxide used is preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the graft copolymer (G). It is preferable that the usage-amount of a reducing agent is 0.01-1 mass part with respect to 100 mass parts of graft copolymers (G).

  Chain transfer agents such as t-dodecyl mercaptan, n-octyl mercaptan, and α-methylstyrene can also be used for the production of poly (meth) acrylic acid alkyl ester (A2).

[Graft copolymer (G)]
The stress relaxation agent for curable resin of the present invention comprises a graft copolymer (G) obtained by grafting a vinyl polymer (B) onto a polymer (A).

  The vinyl polymer (B) is obtained by polymerizing the vinyl monomer (b), and the vinyl monomer (b) is composed of a (meth) acrylic acid ester monomer (b1) and an aromatic vinyl monomer. The body (b2) is an essential component, and any vinyl monomer (b3) and crosslinkable monomer (b4) can be contained as necessary.

  Examples of the (meth) acrylic acid ester monomer (b1) include methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, glycidyl methacrylate, and hydroxyethyl methacrylate. An acrylic acid ester such as methyl acrylate, ethyl acrylate, and n-butyl acrylate. These may be used alone or in combination of two or more.

The content of the (meth) acrylate monomer (b1) in the vinyl monomer (b) (100% by mass) is preferably 0.1 to 99.9% by mass, and 5 to 95% by mass. %, More preferably 5 to 80% by weight, still more preferably 10 to 60% by weight, and most preferably 25 to 60% by weight. By containing 0.1% by mass or more of the (meth) acrylic acid ester monomer (b1), compatibility with the target resin is improved and dispersibility is improved. Thereby, the stress relaxation ability improvement effect at the time of adding to object resin expresses more effectively. Moreover, heat-resistant decomposability improves by making content rate 99.9 mass% or less and using together with an aromatic vinyl monomer (b2).
From the viewpoint of compatibility with the target resin, the vinyl monomer (b) preferably contains methyl methacrylate as the (meth) acrylic acid ester monomer (b1).

Examples of the aromatic vinyl monomer (b2) include styrene and α-methylstyrene. These may be used alone or in combination of two or more.
The content of the aromatic vinyl monomer (b2) in the vinyl monomer (b) (100% by mass) is preferably 0.1 to 99.9% by mass, and more preferably 5 to 95% by mass. Preferably, it is 20-95 mass%, More preferably, it is 40-90 mass%, Most preferably, it is 40-75 mass%. By containing 0.1% by mass or more of the aromatic vinyl monomer (b2), the thermal relaxation resistance of the stress relaxation agent is improved. Moreover, by making content rate 99.9 mass% or less and using together with a (meth) acrylic acid ester monomer (b1), the dispersibility to object resin improves, and stress relaxation ability improves by extension. .
From the viewpoint of thermal decomposition resistance, the vinyl monomer (b) preferably contains styrene as the aromatic vinyl monomer (b2).

  Examples of the optional vinyl monomer (b3) include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile. These may be used alone or in combination of two or more.

  Examples of the crosslinkable monomer (b4) include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, divinylbenzene, polyfunctional Examples thereof include methacrylic group-modified silicone and allyl methacrylate. These may be used alone or in combination of two or more.

In the vinyl monomer (b) (100% by mass), the content of the crosslinkable monomer (b4) is preferably 0.5 to 10.0% by mass, and 1.0 to 10.0% by mass. % Is more preferable, and 1.0 to 5.0% by mass is even more preferable.
When the content of the crosslinkable monomer (b4) in the vinyl monomer (b) (100% by mass) is 0.5% by mass or more, when the graft copolymer (G) is added to the resin If the content rate is 10.0% by mass or less, the effect of lowering the elastic modulus of the obtained molded product is more excellent.

  The polymer obtained by polymerization of the monomer (b) improves the powder properties such as coagulation property and bulk specific gravity. Therefore, the glass transition temperature preferably exceeds 0 ° C, and is 50 to 200 ° C. Is more preferable, and it is further more preferable that it is 80-150 degreeC.

  The numerical value of Tg is a value calculated according to the Fox formula (Formula (6)). In addition, said Tg shall be calculated | required about the polymer obtained by superposing | polymerizing the monomer remove | excluding the crosslinkable monomer (b4) from the vinyl monomer (b). The numerical value described in POLYMER HANDBOOK Volume 1 (WILEY-INTERSCIENCE) is used for the numerical value of Tg of the homopolymer.

  The stress relieving agent of the present invention is obtained when the total amount of the graft copolymer (G) (the total of the polymer (A) and the vinyl polymer (B)) is 100% by mass. It is preferable that they are 95 mass% and a vinyl polymer (B) 5-50 mass%.

  If the content of the polymer (A) in the entire graft polymer (100% by mass) is 50% by mass or more, the resulting molded article has an excellent effect of lowering the elastic modulus, and should be 95% by mass or less. For example, the dispersibility when the graft copolymer (G) is blended with the resin can be improved.

[Production method of graft copolymer (G)]
As a polymerization initiator used for graft polymerization, the same polymerization initiator as that used for producing the poly (meth) acrylic acid alkyl ester (A2) can be used.
As the emulsifier used for the graft polymerization, the same emulsifier as that used for the production of the poly (meth) acrylic acid alkyl ester (A2) can be used.
Moreover, the chain transfer agent similar to the chain transfer agent used for manufacture of poly (meth) acrylic-acid alkylester (A2) can be used for graft polymerization.

  The volume average particle diameter of the graft copolymer (G) in the latex is preferably 10 to 3000 nm, more preferably 10 to 1000 nm, still more preferably 50 to 800 nm, and particularly preferably 120 to 800 nm. If the volume average particle diameter of the graft copolymer (G) in the latex is 10 to 3000 nm, the dispersibility of the graft copolymer (G) in the resin and the viscosity characteristics of the resin composition will be good. Moreover, if it is 120 nm or more, a dispersibility will become more favorable and the stress relaxation ability of hardened | cured material will improve.

The latex of the graft copolymer (G) obtained by emulsion polymerization can be recovered as a powder of the graft copolymer (G) by a treatment such as spray drying, freeze drying, or coagulation. Among these, since the dispersibility of the graft copolymer (G) in the resin is good, the spray drying method is preferable, and since impurities such as an emulsifier can be removed and the purity becomes good, A coagulation method is preferred.
In addition, antioxidant and an additive can be mix | blended with the latex of a graft copolymer (G) as needed.

  In the coagulation method, the graft copolymer (G) is poured into hot water in which calcium chloride, calcium acetate, aluminum sulfate, etc. are dissolved, salted out, and solidified to separate the graft copolymer (G). Then, the separated wet graft copolymer (G) is recovered from the graft copolymer (G) whose water content is reduced by dehydration or the like, and further, this is compressed using a press dehydrator or a hot air dryer. It is a method of drying.

  Examples of the coagulant used for coagulating the graft copolymer (G) from latex include inorganic salts such as aluminum chloride, aluminum sulfate, sodium sulfate, magnesium sulfate, sodium nitrate, and calcium acetate, and acids such as sulfuric acid. And calcium acetate is particularly preferred. These coagulants may be used alone or in combination of two or more, but when used in combination, it is necessary to select a combination that does not form an insoluble salt in water. For example, the combined use of calcium acetate and sulfuric acid or a sodium salt thereof is not preferable because a calcium salt insoluble in water is formed.

  The above-mentioned coagulant is usually used as an aqueous solution. The concentration of the aqueous coagulant solution is preferably 0.1% by mass or more from the viewpoint of stably coagulating and recovering the graft copolymer (G). Further, from the viewpoint of reducing the amount of the coagulant remaining in the recovered graft copolymer (G) and suppressing the deterioration of the electrical characteristics of the molded product, the concentration of the coagulant aqueous solution is 20% by mass or less, particularly It is preferable that it is 15 mass% or less. The amount of the coagulant aqueous solution is not particularly limited, but is preferably 10 parts by mass or more and 500 parts by mass or less with respect to 100 parts by mass of the latex.

  The method of bringing the latex into contact with the coagulant aqueous solution is not particularly limited. Usually, while stirring the coagulant aqueous solution, the method of continuously adding the latex therein and holding it for a certain period of time, the coagulant aqueous solution and the latex, Examples include a method in which a mixture containing a coagulated polymer and water is continuously withdrawn from the container by continuously injecting into a container equipped with a stirrer at a constant ratio. The temperature at which the latex is brought into contact with the coagulant aqueous solution is not particularly limited, but is preferably 30 ° C. or higher and 100 ° C. or lower. The contact time is not particularly limited.

  The coagulated graft copolymer (G) is washed with about 1 to 100 times by mass of water, and the wet graft copolymer (G) separated by filtration is dried using a fluid dryer or a press dehydrator. Is done. What is necessary is just to determine a drying temperature and drying time suitably with the graft copolymer (G) obtained. In addition, the graft copolymer (G) discharged from the press dehydrator or the extruder is not collected, but directly sent to the extruder or the molding machine for producing the resin composition, and then mixed with other thermoplastic resins and molded. It is also possible to get a body.

  In order to suppress blocking during drying and improve powder characteristics such as bulk specific gravity, a plurality of polymer latexes may be added during coagulation. Moreover, you may dry by adding inorganic fillers, such as a silica, a talc, and calcium carbonate; polyacrylic acid ester, polyvinyl alcohol, polyacrylamide, etc. Moreover, suitable antioxidant, an additive, etc. can also be added.

  In the spray drying method, a latex of graft copolymer is sprayed in the form of fine droplets and dried by applying hot air to the latex. As a device for generating droplets, any of a rotating disk type, a pressure nozzle type, a two-fluid nozzle type, a pressurized two-fluid nozzle type, etc. can be used. Moreover, the dryer can be used from a small-sized one used in a laboratory to a large-scale one used industrially.

  The temperature of hot air introduced into the apparatus (hot air inlet temperature), that is, the maximum temperature of hot air that can come into contact with the graft copolymer (G) is preferably 200 ° C. or less, particularly preferably 120 to 180 ° C. In addition, when spray drying, the latex of the graft polymer may be a single latex or a mixture of a plurality of latexes. Furthermore, in order to improve powder characteristics such as blocking and bulk specific gravity during spray drying, an optional component such as silica can be added to perform spray drying.

  The graft copolymer (G) of the present invention can be used as a resin composition by being blended with another resin (hereinafter also referred to as “target resin”) as a stress relaxation agent, and is more excellent when blended with a curable resin. Show the characteristics.

Examples of the curable resin include a thermosetting resin and a photocurable resin. Examples of the thermosetting resin include epoxy resins, phenol resins, unsaturated polyester resins, melamine resins, urea resins, oxetane resins, alkyd resins, polyurethane resins, and polyimide resins. These can be used alone or in combination of two or more.
Examples of the photocurable resin include resins that are cured by irradiation with ultraviolet rays or electron beams, and examples thereof include a photocurable acrylic resin, a photocurable epoxy resin, and a photocurable oxetane resin. In the present invention, as the curable resin, a hybrid curing (dual cure) type of thermosetting and photocuring can be used according to the purpose.
Among these, thermosetting resins are preferable because they have high insulation properties and excellent electrical characteristics and are suitable for the field of electronic materials, and epoxy resins, phenol resins, polyimide resins, and oxetane resins are particularly preferable.

As the epoxy resin, known resins can be used, and the molecular structure, molecular weight, etc. are not particularly limited as long as they have at least two epoxy bonds in the molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol E type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, phenol novolac type epoxy resin, fat Examples thereof include cyclic epoxy resins and glycidylamine type epoxy resins.
In addition, as the epoxy resin, a prepolymer of the epoxy resin, a polyether-modified epoxy resin, a copolymer of the epoxy resin such as a silicone-modified epoxy resin and another polymer, and a part of the epoxy resin are epoxy. Mention may also be made of those substituted with a reactive diluent having a group.

Examples of reactive diluents include resorcing ricidyl ether, t-butylphenyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyl. Methyldimethoxysilane, 1- (3-glycidoxypropyl) -1,1,3,3,3-pentamethylsiloxane, N-glycidyl-N, N-bis [3- (trimethoxysilyl) propyl] amine, etc. And monoalicyclic epoxy compounds such as 2- (3,4) -epoxycyclohexyl) ethyltrimethoxysilane.
These epoxy resins may be used individually by 1 type, and may use 2 or more types together.

[Curable resin composition]
In this invention, a curable resin composition contains the stress relaxation agent and curable resin which consist of the above-mentioned graft copolymer (G). The amount of the powder of the graft copolymer (G) added to the curable resin is preferably 0.5 to 90% by weight, and 0.5 to 20% by weight in a total of 100% by mass of the curable resin and the powder. More preferred.
If the addition amount of the graft copolymer (G) powder is 0.5 to 90% by weight, a curable resin composition having a low elastic modulus and high stress relaxation ability can be obtained.

  When an epoxy resin is used as the curable resin, for example, it can be cured using a curing agent such as an acid anhydride, an amine compound, or a phenol compound. By using a curing agent, it is possible to adjust the curability of the epoxy resin and the properties of the resulting molded product. Especially when an acid anhydride is used as the curing agent, the heat resistance and chemical resistance of the molded product are improved. Since it can improve, it is preferable.

Examples of the acid anhydride include phthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methylhymic anhydride, methylcyclohexene Dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bistrimellitate, glycerol trislimitate, dodecenyl succinic anhydride, polyazelinic anhydride and poly (ethyl octadecane diene) Acid) anhydride. Among these, methylhexahydrophthalic anhydride and hexahydrophthalic anhydride are preferred for applications that require weather resistance, light resistance, heat resistance, and the like.
These may be used alone or in combination of two or more.

Examples of amine compounds include 2,5 (2,6) -bis (aminomethyl) bicyclo [2,2,1] heptane, isophoronediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethylaminopropylamine. Bis (4-amino-3-methyldicyclohexyl) methane, diaminodicyclohexylmethane, bis (aminomethyl) cyclohexane, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyldiphenylmethane, diethyltoluenediamine. In applications where weather resistance, light resistance, heat resistance and the like are required, 2,5 (2,6) -bis (aminomethyl) bicyclo [2,2,1] heptane and isophoronediamine are preferred.
These may be used alone or in combination of two or more.

  Examples of the phenol compound include phenol novolak resins, cresol novolak resins, bisphenol A, bisphenol F, bisphenol AD, and derivatives of diallysates of these bisphenols. These may be used alone or in combination of two or more.

  As the usage-amount of the said hardening | curing agent, since it is excellent in the heat resistance and sclerosis | hardenability of hardened | cured material, 20-120 mass parts is preferable with respect to 100 mass parts of epoxy resins, and 60-110 mass parts is more preferable. The amount of the curing agent used is preferably about 0.7 to 1.3 equivalents, more preferably about 0.8 to 1.1 equivalents in the case of acid anhydrides per equivalent of epoxy group. In the case of amine compounds, active hydrogen is preferably 0.3 to 1.4 equivalents, more preferably about 0.4 to 1.2 equivalents. In the case of phenolic compounds, active hydrogen is preferably It is about 0.3 to 0.7 equivalent, more preferably about 0.4 to 0.6 equivalent.

In this invention, when hardening an epoxy resin, a hardening accelerator, a latent hardening agent, etc. can be used as needed.
As a hardening accelerator, the well-known thing used as a thermosetting catalyst of an epoxy resin can be used, for example, imidazole compounds, such as 2-methylimidazole and 2-ethyl-4-methylimidazole; Examples include adducts of epoxy resins; organophosphorus compounds such as triphenylphosphine; borates such as tetraphenylphosphine tetraphenylborate; and diazabicycloundecene (DBU). These may be used alone or in combination of two or more.
When a curing accelerator is used, the curing accelerator is generally added in an amount of 0.1 to 8 parts by mass, preferably 0.5 to 6 parts by mass with respect to 100 parts by mass of the epoxy resin.

The latent curing agent is solid at room temperature, and liquefies when the epoxy resin is heated and cured to act as a curing agent.
Examples of latent curing agents include dicyandiamide, carbohydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, iminodiacetic acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide dihydrazide, Dodecanedihydrazide, hexadecanedihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4'-bisbenzenedihydrazide 1,4-naphthoic acid dihydrazide, Amicure VDH and Amicure UDH (all trade names, Ajinomoto (registered trademark)) And an organic acid hydrazide such as trihydrazide citrate.
These may be used alone or in combination of two or more.

  Known additives can be used in combination with the curable resin composition as necessary. For example, release agents such as silicone oil, natural wax, synthetic wax; powders such as crystalline silica, fused silica, calcium silicate, and alumina; fibers such as glass fiber and carbon fiber; phosphorus-based, halogen-based, inorganic-based Flame retardants such as flame retardants; heat stabilizers such as phenolic, sulfur and phosphorus antioxidants; halogen trapping agents such as hydrotalcite and rare earth oxides; colorants such as carbon black and bengara; silane coupling agents An ultraviolet absorber or the like can be used. The amount of the additive can be appropriately blended according to the purpose of addition.

As a method for preparing the curable resin composition, any method may be used as long as the above components can be uniformly dispersed and mixed. For example, after mixing a raw material of a predetermined blending amount with a mixer or the like, kneading using a kneading device, or melt-kneading using a hot roll or the like, or cooling and pulverizing, or a raw material of a predetermined blending amount using an organic solvent It can be performed by a widely used technique such as mixing in a solution state. Examples of the kneading apparatus include a raking machine, an attritor, a planetary mixer, a dissolver, a triple roll, a ball mill, and a bead mill. Moreover, these can use 2 or more types together.
In the case of adding an additive or the like to the resin composition, the order of mixing is not particularly limited, but it is preferable to knead the powder as last as possible in order to sufficiently exhibit the effects of the present invention.

[Molded body]
The molded body is obtained by curing the curable resin composition.
When a thermosetting resin is used as the curable resin, the curing condition is, for example, 80 to 180 ° C. and about 10 minutes to 8 hours.
When using a photocurable resin as the curable resin, examples of the light beam used include electron beams, ultraviolet rays, gamma rays, and infrared rays. In addition, as a curing condition of the active energy ray, in the case of curing with ultraviolet rays, a known ultraviolet irradiation device including a high-pressure mercury lamp, an excimer lamp, a metal halide lamp, or the like can be used.
The amount of ultraviolet irradiation is about 50 to 1,000 mJ / cm ² . When hardening with an electron beam, a well-known electron beam irradiation apparatus can be used, and as an electron beam irradiation amount, it is about 10-100 kGy.

  The present curable resin composition can also be used as a semiconductor sealing material. That is, a lead frame, a film of a curable resin, a glass nonwoven fabric impregnated and cured with a curable resin, an insulating support substrate such as ceramics such as alumina, a support member such as a wiring board, glass, or silicon wafer In addition, active elements such as semiconductor chips, transistors, diodes, thyristors, etc., and elements such as passive elements such as capacitors, resistors, resistor arrays, coils, and switches are mounted, and the necessary parts are sealed with the present curable resin composition. can do.

  As a sealing method, a general method can be used. For example, a transfer molding method, a dispensing method, a casting molding method, a printing method, a liquid or semi-cured sheet-like epoxy resin material is used as a substrate. And a method of sealing with a sealant and a compression molding method.

  The present curable resin composition is obtained by the above-described method by using a surface mounting type liquid or solid sealing material; a primary mounting underfill material, a secondary mounting unfilled film material, a liquid sealing material such as a grab top material in wire bond, etc. Sealing sheet for sealing various chips on the substrate at once; sealing film for die bond film, die attach film, interlayer insulating film, coverlay film, etc .; die bond paste, interlayer insulating paste, conductive paste, different It can be used in various applications such as sealing pastes such as a conductive paste; sealing materials for various flat panel displays such as liquid crystal and organic EL.

  This curable resin composition can also be used as an adhesive. That is, between active elements such as semiconductor chips, transistors, diodes, thyristors, etc., passive elements such as capacitors, resistors, resistor arrays, coils, switches, etc., or elements and lead frames, curable resin films, glass A base material such as nonwoven fabric impregnated and cured with a curable resin, an insulating support substrate such as ceramics such as alumina, and a support member such as a wiring board, glass, or silicon wafer can be bonded.

  As a method for bonding, a general method can be used. For example, the resin composition is sandwiched between elements or between an element and a support member by a transfer molding method, a dispensing method, a casting molding method, a printing method, a compression molding method, and the like, and then bonded by curing. Moreover, what shape | molded the resin composition previously in the sheet | seat or film form of the semi-hardened state can also be used.

This curable resin composition can also be used as a resin composition for prepregs, laminates and printed wiring boards. These can be produced by a general method. For example, a prepreg is obtained by impregnating a glass fiber woven fabric with a varnish of the present resin composition and heating and drying to cure the resin composition to a semi-cured state to form a sheet.
A laminated board is obtained by laminating a plurality of prepregs and heating and pressing them. In this case, a metal foil-clad laminate can be obtained by placing a metal foil (for example, copper foil) having a predetermined thickness on one or both sides of the prepreg layer and performing heat-pressure molding.
Furthermore, a printed wiring board can be obtained by producing a conductor pattern by etching or the like on the surface of the metal foil of the laminated board and forming a circuit.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” represent “parts by mass” and “% by mass”, respectively.
The polymer and this polymer powder were evaluated by the method described below.

(Average particle diameter of polymer latex)
The volume average particle size of the polymer latex was measured by the following method. The polymerized latex was diluted with deionized water, and the 50% volume average particle size was measured using a laser diffraction particle size distribution analyzer (SALD-7100, manufactured by Shimadzu Corporation).

(Heat-resistant decomposition (5% weight loss temperature))
The graft copolymer (G) powder was heated at a rate of 10 ° C. while flowing nitrogen at 200 ml / min using a differential thermothermal gravimetric measuring device (TG / DTA6200, manufactured by Seiko Instruments Inc.). Thermogravimetry was performed when the temperature was raised from room temperature to 550 ° C. at a rate of 5 minutes / minute, and a 5% weight reduction temperature was obtained. The evaluation was performed at a 5% weight reduction temperature of the powder, and the higher this temperature, the better the thermal decomposition resistance of the powder, and it was added to the curable resin as a stress relaxation agent for the curable resin. In some cases, it can be determined that a curable resin having excellent thermal decomposition resistance can be obtained.

(Measurement of linear expansion coefficient)
The graft copolymer (G) powder was made into a plate using a hot press and cut into a length of 5 mm, a width of 5 mm, and a thickness of 3 mm to obtain a test piece. Using a thermomechanical analyzer (TMA / SS 6100, manufactured by Seiko Instruments Inc.), while flowing nitrogen at 200 m1 / min, the temperature rise rate was 2 ° C./min, and the load was 5 mN from −140 ° C. to 200 ° C. And a linear expansion curve was obtained. The linear expansion coefficient was determined from the slope of the obtained curve between −30 ° C. and 30 ° C. The smaller the coefficient of linear expansion, for example, when used as a sealing material for semiconductors, the difference in coefficient of linear expansion from the semiconductor element becomes smaller, and the occurrence of warping, cracking, etc. of parts can be suppressed. It can be determined that a curable resin can be obtained.

<Production Example 1> Production of polyorganosiloxane (A1-1) latex 96.2 parts of octamethylcyclotetrasiloxane, 1.9 parts of γ-methacryloyloxypropyldimethoxymethylsilane, and 1.9 parts of tetraethoxysilane were mixed. As a result, 100 parts of an organosiloxane mixture was obtained.
An aqueous solution in which 1.0 part of sodium dodecylbenzenesulfonate was dissolved in 190 parts of deionized water was added to 100 parts of the organosiloxane mixture. This was stirred at 10,000 rpm for 5 minutes using a homomixer, and then passed twice through a homogenizer at a pressure of 20 MPa to obtain an organosiloxane emulsion.

The organosiloxane emulsion was put into a separable flask equipped with a thermometer, a condenser, and a stirring device. Next, the internal temperature of the separable flask was raised to 80 ° C., and a mixture of 0.2 part of sulfuric acid and 10 parts of deionized water was added.
Next, the internal temperature of 80 ° C. was maintained for 6 hours to proceed the reaction, and then cooled to room temperature.
After the obtained reaction solution was kept at room temperature for 6 hours, the reaction product was neutralized to pH 7.0 with a 5% aqueous sodium hydroxide solution to obtain a polyorganosiloxane (A1-1) latex.
The polyorganosiloxane (A1-1) latex was dried at 180 ° C. for 30 minutes and the solid content was determined to be 29.7%. The volume average particle diameter of the polyorganosiloxane (A1-1) latex was 400 nm, and the volume average particle diameter / number average particle diameter (Dv / Dn) was 1.1.

<Production Example 2> Production of polyorganosiloxane (A1-2) latex 96.2 parts of octamethylcyclotetrasiloxane, 1.9 parts of γ-methacryloyloxypropyldimethoxymethylsilane, and 1.9 parts of tetraethoxysilane were mixed. As a result, 100 parts of an organosiloxane mixture was obtained.
An aqueous solution in which 0.65 part of sodium dodecylbenzenesulfonate was dissolved in 300 parts of deionized water was added to 100 parts of the organosiloxane mixture. This was stirred at 20,000 rpm for 3 minutes using an ultra turrax to obtain an organosiloxane emulsion.

In a separable flask equipped with a thermometer, a condenser and a stirrer, 89.0 parts of deionized water, 0.38 part of sulfuric acid and 0.38 part of sodium dodecylbenzenesulfonate were added, and the temperature was raised to 90 ° C. Subsequently, the organosiloxane emulsion was added dropwise over 8 hours while maintaining a temperature of 90 ° C. The reaction was allowed to proceed for 2 hours after completion of the dropwise addition, and cooled to room temperature. The resulting reaction solution was kept at room temperature for 6 hours. Thereafter, the reaction product was neutralized with 5% aqueous sodium hydroxide solution to pH 7.0 to obtain a polyorganosiloxane (A1-2) latex.
The polyorganosiloxane (A1-2) latex was dried at 180 ° C. for 30 minutes and the solid content was determined to be 17.6%. The volume average particle diameter of the polyorganosiloxane (A1-2) latex was 130 nm, and the volume average particle diameter / number average particle diameter (Dv / Dn) was 1.3.

<Production Example 3> Production of polyorganosiloxane (A1-3) latex 98.0 parts of octamethylcyclotetrasiloxane and 2.0 parts of γ-methacryloyloxypropyldimethoxymethylsilane were mixed to obtain 100 parts of an organosiloxane mixture. It was.
300 parts of an aqueous solution prepared by dissolving 0.68 parts of sodium dodecylbenzenesulfonate in deionized water was added to 100 parts of the organosiloxane mixture. This was stirred with a homomixer at 10,000 rpm for 5 minutes and then passed twice through a homogenizer at a pressure of 20 MPa to obtain an organosiloxane emulsion.

A mixture of 10.0 parts of dodecylbenzenesulfonic acid and 90 parts of deionized water was put into a separable flask equipped with a thermometer, a cooling tube and a stirring device, and the internal temperature was raised to 85 ° C. Subsequently, the said organosiloxane emulsion was dripped over 4 hours in the state which maintained the temperature of 85 degreeC. After completion of dropping, the reaction was allowed to proceed for 1 hour and cooled to room temperature. The resulting reaction solution was kept at room temperature for 6 hours. Thereafter, the reaction product was neutralized to pH 7.0 with a 5% aqueous sodium hydroxide solution to obtain a polyorganosiloxane (A1-3) latex.
The polyorganosiloxane (A1-3) latex was dried at 180 ° C. for 30 minutes and the solid content was determined to be 19.0%. The volume average particle diameter of the polyorganosiloxane (A1-3) latex was 70 nm, and the volume average particle diameter / number average particle diameter (Dv / Dn) was 1.4.

<Production Example 4> Production of polyorganosiloxane (A1-4) latex 97.6 parts of octamethylcyclotetrasiloxane, 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane, and 1.9 parts of tetraethoxysilane were mixed. As a result, 100 parts of an organosiloxane mixture was obtained.
An aqueous solution in which 0.7 part of dodecylbenzenesulfonic acid and 0.7 part of sodium dodecylbenzenesulfonate were dissolved in 190 parts of deionized water was added to 100 parts of the organosiloxane mixture. This was stirred for 5 minutes at 10,000 rpm using a homomixer and then passed twice through a homogenizer at a pressure of 20 MPa to obtain an organosiloxane emulsion.

The organosiloxane emulsion was put into a separable flask equipped with a thermometer, a condenser tube and a stirring device, and the internal temperature of the separable flask was raised to 80 ° C. The reaction was allowed to proceed at an internal temperature of 80 ° C. for 6 hours, and then cooled to room temperature. After the obtained reaction solution was kept at room temperature for 6 hours, the reaction product was neutralized to pH 7.0 with a 5% aqueous sodium hydroxide solution to obtain a polyorganosiloxane (A1-4) latex.
The polyorganosiloxane (A1-4) latex was dried at 180 ° C. for 30 minutes and the solid content was determined to be 33.0%. The volume average particle diameter of the polyorganosiloxane (A1-4) latex was 260 nm, and the volume average particle diameter / number average particle diameter (Dv / Dn) was 1.2.

<Example 1> Production of graft copolymer (G-1) Polyorganosiloxane (A1-1) obtained in Production Example 1 on a separable flask equipped with a thermometer, a nitrogen introduction tube, a cooling tube and a stirring device. Latex and deionized water were added.
Polyorganosiloxane (A1-1) latex 185.2 parts (solid content conversion: 55.0 parts)
50 parts of deionized water

Next, the following vinyl monomer (a2) and initiator mixture were added, and the internal temperature of the separable flask was raised to 50 ° C. in a nitrogen atmosphere.
Vinyl monomer (a2) mixture:
Butyl acrylate 14.85 parts Allyl methacrylate 0.15 parts Cumene hydroperoxide 0.08 parts Then, after adding the following catalyst aqueous solution, the internal temperature was set to 60 ° C. After holding for 1 hour, polymerization of the poly (meth) acrylic acid alkyl ester (A2-1) was terminated to obtain a latex of the polymer (A-1).
Catalyst aqueous solution:
Ferrous sulfate 0.003 parts Sodium formaldehyde sulfoxylate 0.2 parts Ethylenediaminetetraacetic acid disodium salt 0.01 parts Deionized water 5.0 parts

Next, the following vinyl monomer (b) and initiator mixture were added dropwise over 4 hours, and after completion of the addition, the mixture was held for 1 hour to complete the polymerization to obtain a latex of the graft copolymer (G-1). It was.
Vinyl monomer (b) mixture:
Methyl methacrylate 5.85 parts Styrene 23.4 parts Allyl methacrylate 0.75 parts (2.5% based on vinyl monomer (B))
t-Butyl hydroperoxide 0.5 parts

The obtained latex of the graft copolymer (G-1) is put into a 35 ° C. aqueous solution containing 4 parts of calcium acetate, the solid is separated, filtered and dried to obtain the graft copolymer (G-1). 100 parts of the powder was recovered.
Table 1 shows the latex volume average particle diameter of the graft copolymer (G-1), the 5% weight reduction temperature of the powder, and the linear expansion coefficient.

<Example 2> Production of graft copolymer (G-2) Polyorganosiloxane (A1-1) obtained in Production Example 1 on a separable flask equipped with a thermometer, a nitrogen introduction tube, a cooling tube, and a stirring device. Latex and deionized water were added.
Polyorganosiloxane (A1-1) latex 185.2 parts (solid content conversion: 55.0 parts)
100 parts of deionized water

Next, 1/4 of the mixture (pre-emulsion) obtained by stirring the following vinyl monomer (a2) and initiator mixture at 14,000 rpm for 1 minute using a homomixer was added, and a nitrogen atmosphere was added. Below, the internal temperature of the separable flask was raised to 80 ° C.
Vinyl monomer (a2) mixture:
2-ethylhexyl acrylate 14.85 parts allyl methacrylate 0.15 parts t-butyl hydroperoxide 0.50 parts sodium dodecylbenzenesulfonate 0.19 parts deionized water 7.5 parts Then, the remainder of the pre-emulsion of the monomer (a2) and the initiator mixture was added dropwise over 1.5 hours, and held for 1 hour after the completion of the addition, to obtain a poly (meth) acrylic acid alkyl ester (A2- The polymerization of 2) was terminated, and a latex of composite rubber (A-2) was obtained.
Catalyst aqueous solution:
Ferrous sulfate 0.003 parts Sodium formaldehyde sulfoxylate 0.2 parts Ethylenediaminetetraacetic acid disodium salt 0.01 parts Deionized water 5.0 parts

  Next, in the same manner as in Example 1, graft polymerization and powder recovery were performed to obtain 100 parts of latex of the graft copolymer (G-2) and powder. Table 1 shows the latex volume average particle diameter of the graft copolymer (G-2), the 5% weight reduction temperature of the powder, and the linear expansion coefficient.

<Examples 3 to 8><Comparative Examples 1 to 5> Production of Graft Copolymer (G-3 to G-13) Using the polyorganosiloxane (A1-1 to 4) obtained in Production Examples 1 to 4 In the same manner as in Example 1, latex and powder of graft copolymer (G-3 to G-13) were obtained.
Table 1 shows the composition of the graft copolymer (G-3 to G-13), the latex volume average particle diameter, the 5% weight reduction temperature of the powder, and the linear expansion coefficient.

Abbreviations in the table are as follows.
n-BA: n-butyl acrylate 2-EHA: 2-ethylhexyl acrylate AMA: allyl methacrylate MMA: methyl methacrylate St: styrene

<Examples 9 to 16><Comparative Examples 6 to 11>
A bisphenol A type epoxy resin (JER828, manufactured by Mitsubishi Chemical Corporation) and the above graft copolymer (G-1 to G-13) are blended in the composition described in Table 2, and a non-contact planetary motion type The mixture was kneaded for 2 minutes with a vacuum mixer (Shinky Co., Ltd., Awatake Nertaro ARV-200) under conditions of rotation of 1000 rpm and revolution of 2000 rpm. This mixture was further kneaded at 200 rpm using a three roll mill (M-80E manufactured by EXAKT) to obtain an epoxy resin composition.
By the method described below, the dispersibility of the graft copolymer and the storage stability of the resin composition were evaluated.

(Dispersibility)
The resin composition was sandwiched between paste cells, and a 50% volume average particle size was measured using a laser diffraction particle size distribution analyzer (SALD-7100, manufactured by Shimadzu Corporation). If the volume average particle size in the paste is approximately the same as the volume average particle size of the latex described in Table 1, it is dispersed to the primary particle size. Can be determined to exist. That is, the closer the volume average particle diameter in the paste is to the latex volume average particle diameter, the higher the dispersibility. The measurement results are shown in Table 2.
◎: Same as the volume average particle diameter of latex ○: 2 to 5 times the volume average particle diameter of latex Δ: 5 to 30 times the volume average particle diameter of latex ×: More than 30 times the volume average particle diameter of latex

(Storage stability)
The obtained resin composition was stored in a constant temperature water bath adjusted to 40 ° C. for 48 hours, and then adjusted to 25 ° C. to obtain a B-type viscometer (VISCOMETER TVB-10 (rotor No. 4)), Toki Sangyo Co., Ltd. The viscosity was measured using a). The lower the viscosity, the better the handleability.

<Examples 17 to 24><Comparative Examples 12 to 17>
After kneading and dispersing the bisphenol A type epoxy resin (JER828, manufactured by Mitsubishi Chemical Corporation) and the graft copolymer, the resulting resin composition is mixed with an acid anhydride curing agent (Ricacid) as shown in Table 3. MH-700 (manufactured by Shin Nippon Rika Co., Ltd.) and a curing accelerator (N-benzyl-2-methylimidazole) were added and mixed with stirring. The obtained resin composition was filled in a mold and cured by heating at 80 ° C. for 2 hours and further at 120 ° C. for 6 hours. Furthermore, annealing treatment was performed at 180 ° C. for 6 hours to obtain a sheet-like molded body having a thickness of 3 mm.
The molded body was evaluated as follows.

(Heat cycle properties)
As an evaluation of the stress relaxation ability, a heat cycle test was performed.
Six molded products obtained by curing a resin composition in which a metal washer is sealed are prepared and placed in a thermostat bath of seven kinds of temperature conditions according to JISC-2105, and three cycles are carried out at each temperature condition. Then, 9 cycles (30 cycles in total) were performed under the most severe temperature conditions. After the test was completed, the frequency of occurrence of cracks in the molded body was investigated. It can be determined that the smaller the value is, the less likely cracks are and the higher the stress relaxation ability.
Evaluation was performed using the following indices, and the results are shown in Table 3. The number of molded bodies in which cracks occurred in parentheses is shown.
○: The number of molded bodies where cracks occurred 0 to 3 Δ: The number of molded bodies where cracks occurred 4 to 5 ×: The number of molded bodies where cracks occurred 6

(Flexural modulus)
The molded body was cut into a length of 60 mm and a width of 10 mm to obtain a test piece, and the bending elastic modulus was measured according to JIS K7171 using a bending tester (STROGRAPH-T, manufactured by Toyo Seiki Seisakusho Co., Ltd.). The measurement was performed at 23 ° C. It can be determined that the smaller the value is, the higher the elastic modulus of the stress relaxation agent is. Evaluation was performed using the following indices, and the results are shown in Table 3.
◎: 2460 MPa or less ○: Over 2460 MPa and less than 2700 MPa ×: 2700 MPa or more

(Glass-transition temperature)
The molded body was cut to a length of 50 mm and a width of 10 mm to obtain a test piece. By a dynamic mechanical property analyzer (EXSTARDMS 6100, manufactured by Seiko Instruments Inc.), a double-end bending mode, a heating rate of 2 ° C./min, The tan δ curve was measured under a frequency of 10 Hz, and the glass transition temperature was determined from the temperature at the peak top of the tan δ curve at 30 to 180 ° C. The closer this value is to the value of Comparative Example 17 (without graft copolymer added), it can be determined that the high Tg of the target resin can be maintained, and it can be determined that a curable resin having excellent heat resistance can be obtained. . Table 3 shows the measurement results.

  As is apparent from Table 1, the graft copolymers (G-1 to G-3, G-6 to G-9, G-11) of Examples 1 to 8 have a high 5% mass reduction temperature. The thermal decomposition resistance was good. On the other hand, the graft polymers (G-5 and G-13) of Comparative Example 2 and Comparative Example 5 that do not contain the aromatic vinyl monomer (b2) in the vinyl monomer (b) have a 5% mass reduction temperature. It was low and the thermal decomposition resistance was inferior.

  As is clear from Table 2, the epoxy resin compositions (H-1 to H-3, H-6 to H-9, H-11) of Examples 9 to 16 are vinyl weights of the graft copolymers used. Since the combination (B) contains the (meth) acrylic acid ester monomer (b1) unit and the aromatic vinyl monomer (b2) unit, both dispersibility and storage stability were good. On the other hand, Comparative Example 6 and Comparative Example using a graft polymer (G-4, G-10, G-12) in which the vinyl polymer (B) does not contain a (meth) acrylic acid ester monomer (b1) unit. The epoxy resin compositions (H-4, H-10, H-12) of No. 8 and Comparative Example 9 were inferior in dispersibility and storage stability.

  As is apparent from Table 3, the molded products (I-1 to I-3, I-6 to I-9, I-11) of Examples 17 to 24 are vinyl polymers of the graft copolymer used ( Since B) contains (meth) acrylic acid ester monomer (b1) units and aromatic vinyl monomer (b2) units, the resin composition obtained without deteriorating the high Tg of the target resin It was possible to reduce the elastic modulus of the product and the molded body and to improve the heat cycle property. On the other hand, Comparative Example 12 and Comparative Example using a graft polymer (G-4, G-10, G-12) in which the vinyl polymer (B) does not contain a (meth) acrylic acid ester monomer (b1) unit In the molded body (I-4, I-10, I-12) of 14 and Comparative Example 15, the heat cycle property of the molded body was inferior.

  The stress relieving agent for curable resins of the present invention has excellent heat decomposability, the curable resin composition containing the stress relieving agent, and the heat decomposing property and stress relaxation of the molded body obtained by curing the resin composition. Since the performance balance of performance can be improved, it can be used in various applications including electronic materials. The curable resin composition is particularly suitable as an adhesive and the molded body is particularly suitable as a semiconductor encapsulant.

Claims (9)

Curability comprising a graft copolymer (G) obtained by grafting a vinyl polymer (B) to a polymer (A) containing a polyorganosiloxane (A1) and / or a poly (meth) acrylic acid alkyl ester (A2). A stress relieving agent for resin,
The stress relaxation agent for curable resin in which a vinyl polymer (B) contains a (meth) acrylic acid ester monomer (b1) unit and an aromatic vinyl monomer (b2) unit.   The said vinyl polymer (B) contains 5-95 mass% (however, a vinyl polymer (B) shall be 100 mass%) the (meth) acrylic acid ester monomer (b1) unit. Stress relieving agent for curable resin.   The curability according to claim 1 or 2, wherein the polymer (A) contains 0.1 to 99.9% by mass of the polyorganosiloxane (A1) (provided that the polymer (A) is 100% by mass). Stress relaxation agent for resin.   The vinyl polymer (B) contains 0.5 to 10% by mass of a crosslinkable monomer (b4) unit (provided that the vinyl polymer (B) is 100% by mass). The stress relaxation agent for curable resins of Claim 1.   The curable resin composition containing the stress relaxation agent for curable resins of any one of Claims 1-4, and curable resin.   The molded object obtained by hardening | curing the curable resin composition of Claim 5.   The semiconductor sealing material using the curable resin composition of Claim 5.   An adhesive using the curable resin composition according to claim 5.   A prepreg, a laminate, and a printed wiring board using the curable resin composition according to claim 5.