JP5971609B2 - Curable resin composition and cured product obtained by curing the same - Google Patents

Description

  The present invention relates to a curable resin composition containing a graft copolymer and a cured product. In particular, the present invention relates to a curable resin composition containing a graft copolymer useful for blending into an epoxy resin composition and an adhesive resin composition, and a cured product obtained by curing the curable resin composition.

  Conventionally, for example, curable resins typified by epoxy resins have been widely used in electrical / electronic products, automobile parts, building materials, and the like. These are rarely used alone, and in many cases, various additives such as inorganic fillers, release agents, rubber fine particles having rubber-like properties are used in combination. In particular, epoxy resins often exhibit brittle properties and have problems with impact resistance and adhesive strength.

  In order to improve impact resistance, it has been proposed to use a graft copolymer containing a rubbery polymer together, and various reports have been made regarding this graft copolymer. Patent Document 1 proposes a method of blending a graft copolymer containing a predetermined functional group as a graft component with an epoxy curable resin and a graft copolymer containing silicone and (meth) acrylate-based units. Patent Document 2 proposes a graft copolymer containing a crosslinkable monomer in the graft component.

JP 2006-104328 A JP 2010-007045 A

  However, since the graft copolymer proposed in Patent Document 1 has a high affinity between the graft component and the matrix resin, when blended with the curable resin composition, the graft portion tends to swell over time and the viscosity is remarkably high. There was a problem of becoming higher. In addition, the invention described in Patent Document 2 suppresses swelling of the graft portion and suppresses thickening by including a crosslinkable monomer in the graft portion. In this case, the graft portion and the curable resin Since the affinity at the interface is weak, there has been a problem that sufficient impact resistance performance such as adhesive strength when blending the graft copolymer cannot be obtained.

  The present invention has been made in view of the above circumstances, and contains a graft copolymer that suppresses an increase in viscosity over time even when blended with a curable resin composition and improves impact resistance and adhesive strength. It aims at providing curable resin composition and its hardened | cured material.

  The curable resin composition of the present invention comprises a rubber polymer, 0.1 to 5% by mass of a vinyl monomer having a glycidyl group (in 100% by mass of the graft copolymer (A)) and a crosslinkable monomer. It is a curable resin composition comprising a graft copolymer (A) obtained by copolymerizing 0.1 to 2% by mass (in 100% by mass of the graft copolymer (A)) and a curable resin (B).

  Here, the curable resin (B) is preferably an epoxy resin, and preferably further contains a curing agent for epoxy resin and / or a curing accelerator for epoxy resin. The cured product of the present invention is a cured product obtained by curing an adhesive using the curable resin composition described above, or a cured product obtained by applying the adhesive to a substrate such as a steel plate and curing it. It is.

  According to the present invention, it is possible to obtain a curable resin composition, an adhesive, and a cured product that suppresses an increase in viscosity over time and is excellent in impact resistance and adhesive strength.

  Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited only to these embodiments.

Graft copolymer (A)
The graft copolymer (A) of the present invention comprises a rubbery polymer and a graft part bonded to the rubbery polymer. The rubbery polymer forms a core part, and the graft part forms a shell part to form a so-called core / shell structure. The shell portion may have a multilayer structure having two or more phases. The presence of the core portion made of a rubbery polymer can improve the impact resistance and adhesive strength of the resulting epoxy cured product, and the graft portion is a curable resin (B) of the graft copolymer (A). ), The elastic modulus of the curable resin composition can be reduced.
Further, since the rubbery polymer has a cross-linked structure and is hardly compatible with the curable resin (B), it hardly reduces the glass transition temperature (Tg) of the cured product of the obtained curable resin (B). . Since there is little fall of Tg, it is rare to reduce the heat resistance of the hardened | cured material obtained.

(Rubber polymer)
Examples of the rubbery polymer of the graft copolymer (A) include (i) a diene rubber that is a polymer of a diene monomer, and (ii) a polymer of a (meth) acrylate monomer. Examples include acrylic rubber, (iii) silicone rubber that is a polymer of silicone monomers, and (iv) composite rubber of silicone rubber and diene rubber or acrylic rubber.
The type of the rubbery polymer is appropriately selected according to the target performance. In the present invention, a composite rubber of silicone rubber and acrylic rubber is preferable from the viewpoint of impact resistance strength and adhesive strength imparting effect.

(i) Diene rubber The diene rubber can be obtained by polymerizing 1,3-butadiene and, if necessary, a vinyl monomer copolymerizable therewith.
Examples of vinyl monomers include aromatic vinyl monomers such as styrene and α-methylstyrene, alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; alkyl acrylates such as ethyl acrylate and n-butyl acrylate; ) Vinyl cyanide monomers such as acrylonitrile.
Furthermore, polyfunctional aromatic vinyl monomers such as divinylbenzene and divinyltoluene, polyfunctional (meth) acrylates such as ethylene glycol dimethacrylate and 1,3-butanediol diacrylate; allyl (meth) acrylate, diallyl phthalate, diallyl Crosslinkable monomers such as di- and trially monomers such as sebacate and triallyltriazine can also be used in combination.
These vinyl monomers and crosslinkable monomers may be used alone or in combination of two or more.

  When 1,3-butadiene is polymerized with a vinyl monomer and / or a crosslinkable monomer, t-dodecyl mercaptan, n-octyl mercaptan, α-methylstyrene or the like is used as a chain transfer agent. Can be used together. In these, t-dodecyl mercaptan and n-octyl mercaptan are preferable.

As a polymerization method of the diene rubber, an emulsion polymerization method is preferable.
Examples of the polymerization initiator used in emulsion polymerization include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, t- Organic peroxides such as butyl hydroperoxide; redox initiators that are a combination of persulfate or organic peroxide and one or more reducing agents.
Polymerization can be appropriately carried out in the range of about 40 to 80 ° C. depending on the kind of polymerization initiator.

  In the emulsion polymerization, known emulsifiers can be used as appropriate, and single-stage or multi-stage seed polymerization can be used. Further, soap-free polymerization may be used. In controlling the primary particle size, the rubber latex obtained can be produced by a method of enlargement with an acid or salt.

(ii) Acrylic rubber The acrylic rubber can be obtained by polymerizing alkyl (meth) acrylate and, if necessary, other vinyl monomers copolymerizable therewith.
Examples of the alkyl (meth) acrylate include methyl acrylate, ethyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, 2-ethylhexyl (meth) acrylate, ethoxyethoxyethyl acrylate, methoxytripropylene glycol acrylate, Examples include 4-hydroxybutyl acrylate, lauryl methacrylate, and stearyl methacrylate.
In these, since it is suitable for emulsion polymerization, the C2-C18 alcohol (meth) acrylate is preferable. Examples of the (meth) acrylate of an alcohol having 2 to 18 carbon atoms include ethyl acrylate, i-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate.
These alkyl (meth) acrylates may be used individually by 1 type, and may use 2 or more types together.
In the present invention, “(meth) acrylate of alcohol having 2 to 18 carbon atoms” refers to an esterified product of (meth) acrylic acid and alcohol having 2 to 18 carbon atoms.

Examples of the other vinyl monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, and vinyl toluene; vinyl cyanide monomers such as (meth) acrylonitrile; phenyl methacrylate, benzyl methacrylate, and the like. (Meth) acrylate having an aromatic ring; (meth) acrylic acid-modified silicone; fluorine-containing vinyl monomer.
These may be used alone or in combination of two or more.

Furthermore, a monomer having two or more unsaturated bonds in the molecule can be used in combination. A monomer having two or more unsaturated bonds in the molecule has a role as a crosslinking agent or a graft crossing agent.
Examples of the crosslinking agent include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, divinylbenzene, and polyfunctional (meth) acrylic acid-modified silicone.
Examples of the graft crossing agent include allyl methacrylate, triallyl cyanurate, and triallyl isocyanurate. Allyl methacrylate can also be used as a crosslinking agent.
These crosslinking agents and graft crossing agents may be used alone or in combination of two or more.

The other vinyl monomer is an alkyl (meth) acrylate, another vinyl monomer, and if necessary, a total of 100% by mass of monomers having two or more unsaturated bonds in the molecule, It is preferable to contain 30 mass% or less.
The monomer having two or more unsaturated bonds in the molecule is alkyl (meth) acrylate, another vinyl monomer as required, or a monomer having two or more unsaturated bonds in the molecule. It is preferable to contain 20 mass% or less with respect to a total of 100 mass%, and it is more preferable to contain 0.1-18 mass%.

  The acrylic rubber may have a single layer or a multilayer structure of two or more layers. An acrylic composite rubber containing two or more types of components and having two or more Tg's may also be used.

  As a polymerization method of the acrylic rubber, an emulsion polymerization method is preferable. Moreover, you may use a forced emulsion polymerization method as needed. Examples of the polymerization initiator used at the time of emulsion polymerization include the polymerization initiators exemplified in the description of the diene rubber.

In emulsion polymerization, anionic, cationic and nonionic emulsifiers can be used.
Examples of the anionic emulsifier include carboxylic acid salts such as potassium oleate, sodium stearate, sodium myristate, sodium N-lauroyl sarcosinate and dipotassium alkenyl succinate; sulfate salts such as sodium lauryl sulfate; dioctyl sulfosuccinic acid Examples thereof include sulfonates such as sodium, sodium dodecylbenzenesulfonate and sodium alkyldiphenyl ether disulfonate; and phosphate ester salts such as sodium polyoxyethylene alkylether phosphate.

The amount of the emulsifier used can be appropriately determined depending on the emulsifier to be used, the type and blending ratio of the monomer components, and the polymerization conditions. 1 part by mass or more is preferable, and 0.5 part by mass or more is more preferable. Moreover, in order to suppress the residual amount to a polymer, 10 mass parts or less are preferable with respect to a total of 100 mass parts of monomer components used for emulsion polymerization, and 5 mass parts or less are more preferable.
Moreover, when controlling a primary particle diameter, it can also manufacture using the method of enlarging the obtained rubber latex with an acid or a salt.

(iii) Silicone rubber As the silicone rubber, polyorganosiloxane having a vinyl polymerizable functional group is preferably used. The polyorganosiloxane can be obtained, for example, by polymerizing dimethylsiloxane, vinyl polymerizable functional group-containing siloxane, and, if necessary, a siloxane-based crosslinking agent.
Examples of dimethylsiloxane include 3- or more-membered dimethylsiloxane-based rings, and those having 3 to 7 members are preferable. Specific examples include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane. These dimethylsiloxanes may be used alone or in combination of two or more.

The vinyl polymerizable functional group-containing siloxane contains a vinyl polymerizable functional group and can be bonded to dimethyl siloxane via a siloxane bond. Considering the reactivity with dimethyl siloxane, the vinyl polymerizable functional group is Various alkoxysilane compounds contained are preferred.
Specifically, β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethylsilane, methacryloyloxysilane such as γ-methacryloyloxypropyldiethoxymethylsilane and δ-methacryloyloxybutyldiethoxymethylsilane, vinylsiloxane such as tetramethyltetravinylcyclotetrasiloxane, vinylphenylsilane such as p-vinylphenyldimethoxymethylsilane, Mercaptosiloxanes such as γ-mercaptopropyldimethoxymethylsilane and γ-mercaptopropyltrimethoxysilane And the like.
These may be used alone or in combination of two or more.

  As the siloxane-based crosslinking agent, trifunctional or tetrafunctional silane-based crosslinking agents are preferable, and examples thereof include trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, and tetrabutoxysilane.

  For polymerization of polyorganosiloxane, for example, a mixture (hereinafter referred to as “siloxane mixture”) containing the above-mentioned dimethylsiloxane, vinyl-polymerizable functional group-containing siloxane, and, if necessary, a siloxane-based crosslinking agent is used with an emulsifier and water. The emulsified latex is made into fine particles using a homomixer that makes fine particles by shearing force generated by high-speed rotation, or a homogenizer that makes fine particles using high-pressure generators, and then polymerized at high temperature using an acid catalyst. Then, it can be carried out by neutralizing the acid with an alkaline substance.

Examples of the method for adding an acid catalyst used for polymerization include a method of mixing with a siloxane mixture, an emulsifier and water, a method of dropping a latex in which a siloxane mixture is finely divided into a high-temperature acid aqueous solution at a constant rate, and the like. Considering that the primary particle diameter of siloxane can be easily controlled, a method in which a latex in which a siloxane mixture is finely divided is dropped into a high-temperature acid aqueous solution at a constant rate is preferable.
The method of mixing the siloxane mixture, the emulsifier, water and / or the acid catalyst includes mixing by high-speed stirring, mixing by a high-pressure emulsifier such as a homogenizer, etc., but the method using the homogenizer is the primary particle size of the polyorganosiloxane. This is a preferable method because the distribution becomes narrow.

The emulsifier used at the polymerization of the polyorganosiloxane is preferably an anionic emulsifier, and examples thereof include sodium alkylbenzene sulfonate, sodium polyoxyethylene nonylphenyl ether sulfate, and sodium lauryl sulfate.
Of these, sodium alkylbenzene sulfonate and sodium lauryl sulfate are preferred.

Examples of the acid catalyst used in the polymerization of the 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 may be used alone or in combination of two or more.
The polymerization can be stopped by cooling the reaction solution and further neutralizing the latex with an alkaline substance such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate or the like.

(iv) Composite rubber Composite rubber is a rubber obtained by combining the above-mentioned silicone rubber and diene rubber or acrylic rubber, and is a composite rubber of silicone rubber and acrylic rubber (silicone / acrylic composite rubber). ) Is preferred.
The silicone / acrylic composite rubber can be prepared by adding an alkyl (meth) acrylate component to a polyorganosiloxane latex and polymerizing with a normal polymerization initiator.
As a method of adding the alkyl (meth) acrylate component, there are a method of adding it all at once to the polyorganosiloxane latex and a method of dropping it into the polyorganosiloxane latex at a constant rate.

As the polyorganosiloxane, the polyorganosiloxane exemplified in the above description of the silicone rubber can be used.
As the alkyl (meth) acrylate component, the alkyl (meth) acrylate exemplified in the above description of the acrylic rubber can be used.
Moreover, the alkyl (meth) acrylate component may use together the monomer which has a 2 or more unsaturated bond in a molecule | numerator. As the monomer having two or more unsaturated bonds in the molecule, a monomer having two or more unsaturated bonds in the molecule exemplified in the description of the acrylic rubber can be used.

  As a polymerization initiator used at the time of superposition | polymerization of an alkyl (meth) acrylate component, the polymerization initiator illustrated in description of the previous diene rubber is mentioned.

(Graft part)
As a monomer which comprises the graft part of a graft copolymer (A), it is a monomer (graft monomer) copolymerizable with the polymer which comprises the rubber-like polymer mentioned above.
Examples of such graft monomers include aromatic vinyl monomers such as styrene and α-methylstyrene; alkyl acrylates such as ethyl acrylate and n-butyl acrylate; alkyl methacrylates such as methyl methacrylate and ethyl methacrylate; phenyl Examples thereof include (meth) acrylates having an aromatic ring such as methacrylate and benzyl methacrylate; vinyl cyanide monomers such as (meth) acrylonitrile; and crosslinkable monomers exemplified in the description of the diene rubber.
Moreover, the chain transfer agent illustrated in description of diene rubber can also be used together.

  In the present invention, in blending the graft copolymer (A) as a curable resin composition, the graft portion is imparted to impart interfacial strength between the curable resin (B) and the graft copolymer (A). Contains a vinyl monomer having a glycidyl group. Examples of the vinyl monomer having a glycidyl group include glycidyl (meth) acrylate and glycidyl vinyl styrene. Among these, glycidyl (meth) acrylate is preferable.

  In the present invention, the content of the vinyl monomer having a glycidyl group in 100% by mass of the graft copolymer (A) is 0.1 to 5% by mass, more preferably 0.2 to 4% by mass, 0.5-3 mass% is further more preferable, and 0.7-1.5 mass% is the most preferable. If the content of the monomer having a functional group is 0.1% by mass or less, the interface strength between the curable resin (B) and the graft copolymer (A) tends to be insufficient. The effect of adhesive strength is difficult to express. In addition, when the content is 5% by mass or more, the interface affinity between the curable resin (B) and the graft copolymer is increased, and the viscosity when blended with the curable resin (B) tends to increase.

  Further, the graft copolymer (A) of the present invention uses a crosslinkable monomer in the graft portion for the purpose of suppressing the swelling of the graft portion and suppressing the increase in viscosity when blended with the curable resin (B). . Examples of the crosslinkable monomer include polyfunctional polymerizable monomers such as polyfunctional poly (meth) acrylates (dihydroxydi (meth) acrylate, trihydroxytri (meth) acrylate, etc.), polyvinyl compounds, and vinyl groups. A containing (meth) acrylate compound etc. are mentioned. More specifically, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1 , 1,1-trimethylolpropane tri (meth) acrylate, diglycidyl ether di (meth) acrylate of bisphenol A, allyl (meth) acrylate, 1,6 hexanediol di (meth) acrylate, 1,9 nonanediol di ( And (meth) acrylate and divinylbenzene.

The content of the crosslinkable monomer unit in the graft portion of the graft copolymer (A) is 0.1 to 2% by mass in the graft copolymer A (100%), and 0.1 to 1.5%. % By mass is preferable, and 0.2 to 1.0% by mass is more preferable.
If the crosslinkable monomer is less than 0.1% by mass, the graft portion is not sufficiently crosslinked, and thus the viscosity increase with time is not suppressed. On the other hand, if it exceeds 2% by mass, the interface strength with the matrix resin becomes weak, which may be disadvantageous in terms of strength.

(Additive)
Furthermore, an antioxidant can be added to the graft copolymer (A) in advance as long as the characteristics are not impaired. When the graft copolymer (A) contains an antioxidant, it becomes easy to obtain reliability over a long period of use.
Examples of antioxidants are hindered phenols, specifically 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-methylenebis (2,6-di-t-). Butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-p-cresol, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythritol Tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydride) Xylphenyl) propionate], n-octadecyl-3- (4 ′, 5′-di-t-butylphenol) propionate, n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-t-butylphenol) Propionate, stearyl-2- (3,5-di-t-butyl-4-hydroxyphenol) propionate, distearyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, 2-t-butyl-6 -(3-t-butyl-5-methyl-2-hydroxybenzyl) -4-methylphenyl acrylate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnama Mid), 3,9-bis {2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1- Methylethyl} -2,4,8,10-tetraoxaspiro [5,5] undecane, 4,4′-thiobis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2- Methyl-4-hydroxy-5-tert-butylphenol) butane.
These may be used alone or in combination of two or more.

(Polymerization method of graft copolymer (A))
The mass ratio of the rubber polymer to the graft part is preferably in the range of 1: 9 to 9: 1 in terms of the mass ratio of the raw material monomers.
The graft copolymer (A) of the present invention can be obtained by polymerizing a monomer constituting the graft portion in the presence of a rubbery polymer latex. At this time, a free polymer that is polymerized independently and not chemically bonded to the rubbery polymer is also produced, but the present invention is referred to as a graft portion including the free polymer.

  The graft polymer (A) can be produced by aqueous emulsion polymerization, and can be produced by one-stage or multistage polymerization.

For the graft polymerization, an anionic, cationic or nonionic emulsifier can be used.
Examples of the anionic emulsifier include carboxylic acid salts such as potassium oleate, sodium stearate, sodium myristate, sodium N-lauroyl sarcosinate and dipotassium alkenyl succinate; sulfate salts such as sodium lauryl sulfate; dioctyl sulfosuccinic acid Examples thereof include sulfonates such as sodium, sodium dodecylbenzenesulfonate and sodium alkyldiphenyl ether disulfonate; and phosphate ester salts such as sodium polyoxyethylene alkylether phosphate.

Examples of the polymerization initiator used in the graft polymerization include persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate; diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, t- Organic peroxides such as butyl hydroperoxide; redox initiators that are a combination of persulfate or organic peroxide and one or more reducing agents.
Polymerization can be appropriately carried out in the range of about 40 to 80 ° C. depending on the kind of polymerization initiator.

  Moreover, a chain transfer agent can be used as needed at the time of graft polymerization. As the chain transfer agent, t-dodecyl mercaptan, n-octyl mercaptan, α-methylstyrene and the like can be used in combination. In these, t-dodecyl mercaptan and n-octyl mercaptan are preferable.

  The volume average primary particle diameter of the graft copolymer (A) latex is preferably 0.01 to 3 μm, more preferably 0.05 to 2 μm, and further preferably 0.1 to 1.5 μm. If the volume average primary particle diameter of the graft copolymer (A) is in the range of 0.01 to 3 μm, the balance between dispersibility in the curable resin (B) and impact resistance is excellent.

The graft copolymer (A) of the present invention can be recovered from a latex as a powder by a known technique such as spray drying, freeze drying, or coagulation. Of these, the spray drying method is preferred. The spray drying method reduces the thermal history of the graft copolymer (A), suppresses heat fusion between the graft copolymer (A) particles, and dispersibility in the curable resin (B). Becomes better.
In addition, antioxidant and an additive can also be previously mix | blended with graft copolymer (A) latex as needed.

In the spray drying method, the latex of the graft copolymer (A) 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 (A) is preferably 200 ° C. or less, particularly preferably 120 to 180 ° C.
Moreover, when spray-drying, the latex of the graft polymer (A) 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 volume average particle diameter of the powder of the graft copolymer (A) obtained by performing the spray drying treatment is preferably in the range of 10 to 200 μm, and more preferably in the range of 20 to 180 μm.

The proportion of moisture contained in the powder of the graft copolymer (A) is preferably 1.5% by mass or less, and more preferably 1% by mass or less.
If the ratio of the water content of the powder of the graft copolymer (A) is 1.5% by mass or less, there is little risk of cracks occurring when the resin composition is molded.

Curable resin (B)
This invention is a curable resin composition which mix | blended the graft copolymer (A) and curable resin (B). Examples of the curable resin (B) include a thermosetting resin (B) and a photocurable resin (B). For example, an epoxy resin, a phenol resin, an unsaturated polyester resin, a melamine resin, and a urea resin can be used. Moreover, if there is no malfunction, they can be mixed and used. Among these, epoxy resins are preferably used because they increase the adhesive strength.

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.

  As a hardening | curing agent of an epoxy resin, an acid anhydride, an amine compound, and a phenol compound are mentioned, for example. By using a curing agent, the curability and cured product characteristics of the epoxy resin can be adjusted.

Examples of the acid anhydride include phthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methyl hymic anhydride, methylcyclohexene. Dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bis trimellitate, glycerol trislimitate, dodecenyl succinic anhydride, poly azelaic 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, 3,3'-diamino Diaminodiphenylsulfone such as diphenylsulfone (3,3'-DDS), 4,4'-diaminodiphenylsulfone (4,4'-DDS), diaminodiphenyl Ether (DADPE), bisaniline, benzyldimethylaniline, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), 4,4'-diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 3,3'- Diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,4-diaminophenol, 2,5-diaminophenol, o-phenylenediamine, m-phenylenediamine P-phenylenediamine, 2,3-tolylenediamine, 2,4-tolylenediamine, 2,5-tolylenediamine, 2,6-tolylenediamine, 3,4-tolylenediamine, methylthiotoluenediamine, Diethyltoluenediamine, dicyandiamide And the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the phenol compound include phenol novolac resins, cresol novolac 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.
Although there is no restriction | limiting in particular about the usage-amount of the hardening | curing agent of an epoxy resin, It is necessary to add the stoichiometric amount of an epoxy group.

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.

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, mold release agents such as silicone oil, natural wax and synthetic wax; powders such as crystalline silica, fused silica, calcium silicate and alumina; fibers such as glass fibers and carbon fibers; flame retardants such as antimony trioxide; Halogen trapping agents such as hydrotalcite and rare earth oxides; colorants such as carbon black and bengara; silane coupling agents can be used.

Preparation method of curable resin composition As a preparation method of curable resin composition, a well-known technique can be used. For example, the graft copolymer (A) and the curable resin (B) can be mixed in a solution state, or can be melt-mixed using a mixing roll or a kneader.
The mass ratio of the graft copolymer (A) and the curable resin (B) is 0.1: 99.9 to 50:50, preferably 1:99 to 40:60.

  The curable resin composition of the present invention can also be used as an adhesive for structural use, general office work, medical use, and electronic material. As adhesives for electronic materials, interlayer adhesives for multilayer substrates such as build-up substrates, die bonding agents, semiconductor adhesives such as underfills, BGA reinforcing underfills, anisotropic conductive films (ACF), Examples thereof include an adhesive for mounting such as anisotropic conductive paste (ACP).

  Moreover, a metal steel plate is mentioned as a preferable board | substrate which apply | coats the curable resin composition of this invention. Metallic steel sheets include SPC steel sheets, electrogalvanized steel sheets, hot dip galvanized steel sheets, organic surface-treated steel sheets, alloyed galvanized steel sheets, zinc-nickel alloy plated steel sheets, tin-lead plated steel sheets, cationic electrodeposition coated steel sheets, An aluminum plate, a magnesium plate, etc. are included and there is no restriction | limiting in the kind.

  In addition to being used as an adhesive, the composition of the present invention can also be used for general-purpose articles in which a thermosetting resin such as an epoxy resin is used. For example, paints, coating agents, molding materials (including sheets, films, FRP, etc.), insulating materials (including printed circuit boards, electric wire coatings, etc.), sealants and the like can be mentioned. As sealing agents, capacitors, transistors, diodes, light emitting diodes, pottings for ICs, LSIs, etc., dipping, transfer mold sealing, pottings for ICs, LSIs such as COB, COF, TAB, etc., flip chip Such as underfill for sealing, sealing at the time of mounting IC packages such as QFP, BGA, and CSP (including reinforcing underfill).

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
In the examples, “parts” and “%” represent “parts by mass” and “% by mass”, respectively.

(1) Graft copolymer (A) Volume average particle diameter of latex Graft copolymer latex is diluted with deionized water, and a laser diffraction scattering particle size distribution analyzer (LA-910, manufactured by Horiba, Ltd.) is used. Used, 50% volume average particle size was measured.

(2) Solid content of latex Graft copolymer (A) Latex was weighed in an aluminum dish and dried under the conditions of 180 ° C x 30 minutes, and the solid content of the graft copolymer (A) was removed from the residue in the aluminum dish. Asked.

Production Example Production of Polyorganosiloxane Polymer Latex (S-1) (Core Part) To 100 parts of octamethylcyclotetrasiloxane, 2 parts of tetraethoxysilane and 2 parts of γ-methacryloyloxypropyldimethoxymethylsilane were mixed. Thus, a siloxane-based mixture was obtained. To this was added 150 parts of distilled water in which 1.00 part of sodium dodecylbenzenesulfonate was dissolved, and the mixture was stirred at 10000 rpm for 5 minutes with a homomixer and then passed twice through a homogenizer at a pressure of 20 MPa to provide a stable premixed organosiloxane. An emulsion was obtained.

  The above emulsion was placed in a separable flask equipped with a cooling condenser, and a mixture of 0.20 parts of sulfuric acid and 31.8 parts of ion-exchanged water was added over 3 minutes. The emulsion was maintained at 80 ° C. for 7 hours and then cooled. Next, this reaction product was kept at room temperature for 12 hours and then neutralized with an aqueous sodium hydroxide solution to obtain a polyorganosiloxane latex (S-1). A part of the polyorganosiloxane latex was weighed in an aluminum dish and dried at 180 ° C. for 30 minutes to obtain a solid content of 29.4%. The volume average particle diameter of the polyorganosiloxane in this latex was 384 nm.

Graft copolymer (A-1) (production of graft part (shell part))
102 parts of polyorganosiloxane latex (S-1) (30.0 parts in terms of solid content) was collected in a separable flask, and 143.8 parts of ion-exchanged water and 0.5 part of sodium dialkylsulfosuccinate were added and mixed. Thereafter, a mixture of 49.5 parts of n-butyl acrylate (nBA), 0.5 part of allyl methacrylate (AMA) and 0.09 part of tertiary butyl hydroperoxide was added.
The atmosphere in the flask was replaced with nitrogen by passing a nitrogen stream through the separable flask, and the temperature was raised to 50 ° C. When the liquid temperature reached 50 ° C., an aqueous solution in which 0.02 part of sodium ascorbate and 0.05 part of ammonium persulfate were dissolved in 3.5 parts of distilled water was added to initiate radical polymerization. In order to complete the polymerization of butyl acrylate, this state was maintained for 1 hour to obtain a latex of a composite rubber of polyorganosiloxane and polybutyl acrylate.

After the latex temperature dropped to 65 ° C., 18.9 parts methyl methacrylate (MMA), 0.4 parts ethyl acrylate, 0.5 parts glycidyl methacrylate, 0.2 parts allyl methacrylate, sodium dialkylsulfosuccinate A pre-emulsification treatment was performed on a mixed solution of 2 parts and 15 parts of ion-exchanged water with a homomixer to obtain a pre-emulsified mixture. The pre-emulsified mixture was added dropwise over 1 hour to polymerize. After completion of dropping, the temperature was kept at 60 ° C. or higher for 1 hour, and then cooled to obtain a latex of graft copolymer (A-1).
The obtained graft copolymer (A-1) latex had a volume average particle size of 770 nm and a solid content of 29.7%. The obtained latex was sprayed in the form of fine droplets by a pressure nozzle method using a spray dryer and dried at a hot air inlet temperature of 150 ° C. to obtain a powdered graft copolymer (A-1).

Graft copolymer (A-2) to (A-4)
Except having changed the monomer ratio of a graft part into the ratio of Table 1, operation similar to manufacture example 1 was performed and the graft copolymers (A-2)-(A-4) were obtained.

ｎＢＡ＝ｎ−ブチルアクリレート
ＡＭＡ＝アリルメタクリレート
ＭＭＡ＝メチルメタクリレート
ＥＡ＝エチルアクリレート
ＧＭＡ＝グリシジルメタクリレート Table 1

nBA = n-butyl acrylate AMA = allyl methacrylate MMA = methyl methacrylate EA = ethyl acrylate GMA = glycidyl methacrylate

Preparation of cured epoxy resin A bisphenol A type epoxy resin (828, manufactured by Mitsubishi Chemical Corporation), an acid anhydride-based curing agent (Licacid MH-700, manufactured by Shin Nippon Rika Co., Ltd.), and a graft copolymer Blended with the composition described in Table 2 and kneaded with three rolls to obtain a resin composition.
Next, a curing accelerator (2-ethyl 4-methylimidazole) was added and stirred and mixed, and the resulting resin composition was filled in a mold and heated at 80 ° C. for 2 hours and further at 120 ° C. for 6 hours. Cured to obtain a sheet-like molded body.
The molded body was evaluated as follows.

Charpy impact strength A cured epoxy resin was cut out and the Charpy impact strength was measured according to JISK-7111.

Flexural modulus The molded body was cut into a length of 60 mm, a width of 10 mm and a thickness of 3 mm to obtain a test piece, and the flexural modulus was measured according to JIS K7171.

Crack resistance The epoxy resin composition before curing was placed in an aluminum petri dish together with a SUS washer (JISB1251), and a cured epoxy resin was produced in which the washer was sealed under the same curing conditions.
The obtained cured product was repeatedly subjected to heat treatment under the conditions described below in accordance with JISC2105, and the presence or absence of generated cracks was visually observed.
The test was carried out with n = 5, visually confirmed every 3 cycles, and the cycle conditions where the number of cracks reached 3 was counted.
Cycle conditions;
(a): -10 ° C x 30 minutes → 105 ° C x 30 minutes 3 cycles
(b): -20 ° C x 30 minutes → 105 ° C x 30 minutes for 3 cycles
(c): -30 ° C x 30 minutes → 105 ° C x 30 minutes 3 cycles
(d): -40 ° C x 30 minutes → 105 ° C x 30 minutes 3 cycles
(e): -55 ° C x 30 minutes → 105 ° C x 30 minutes 3 cycles
(f): -55 ° C x 30 minutes → 130 ° C x 30 minutes 3 cycles
(g): -55 ° C x 30 minutes → 150 ° C x 30 minutes 3 cycles

Storage stability A bisphenol A type epoxy resin (828, manufactured by Mitsubishi Chemical Corporation) and a graft copolymer were blended in the composition described in Table 2, and kneaded with three rolls to obtain a resin composition.
The initial viscosity when the obtained epoxy resin composition was held at 40 ° C., the viscosity after 7 days, and the viscosity after 14 days were measured with a B-type viscometer. The initial viscosity was 100, and the viscosity after 7 days and the viscosity after 14 days were expressed.

Table 2

T-type peeling Three rolls were kneaded with the composition shown in Table 3 to obtain an epoxy resin composition. The obtained epoxy resin composition was applied to an SPCC steel sheet, superimposed and cured under the conditions of 180 ° C. × 30 minutes, and the adhesive strength was measured in accordance with JISK-6854-3.

Table 3

Curing agent (a): Ricacid MH-700 (4-methylhexahydrophthalic anhydride / hexahydrophthalic anhydride = 70/30 mixture, manufactured by Nippon Nippon Chemical Co., Ltd.)
Curing agent (b) DCMU99 (3- (3,4-dichlorophenyl) -1,1-dimethylurea Hodogaya Chemical Co., Ltd.)
Curing catalyst (a) 2E4MZ (2-ethyl-4-methylimidazole, manufactured by Shikoku Kasei Co., Ltd.)
Curing catalyst (b)-DICY7 (Dicyandiamide, manufactured by Mitsubishi Chemical Corporation)
Filler ・ ・ ・ J-100 (Glass beads Potters / Barotini)

As shown in Table 4, in Examples 1 to 3 using the graft copolymers A-1 to A-3 of the present invention, the Charpy impact strength, flexural modulus, crack resistance and storage stability are excellent. I understand.
As can be seen from Table 5, in Examples 4 to 6 using the graft copolymers A-1 to A-3 of the present invention, the adhesive strength (T-type peel test) was good. On the other hand, the graft strength of graft copolymer A-4 which is outside the scope of the present invention having no glycidyl group in the graft portion was inferior. In particular, the adhesive strength near 23 ° C. was clearly lower than that of the curable resin composition of the present invention.

表５

Table 4

Table 5

Claims (8)

In the rubber polymer, 0.2 to 1.5 % by mass of a vinyl monomer having a glycidyl group (in 100% by mass of the graft copolymer (A)) and 0.1 to 2% by mass of a crosslinkable monomer ( A curable resin composition comprising a graft copolymer (A) obtained by copolymerizing a graft copolymer (A) in 100% by mass and a curable resin (B).   The rubbery polymer of the graft copolymer (A) is (i) a diene rubber that is a polymer of a diene monomer, (iii) a silicone rubber that is a polymer of a silicone monomer, or ( The curable resin composition according to claim 1, which is a composite rubber of iv) silicone rubber and diene rubber or acrylic rubber. The curable resin composition according to claim 1 or 2 , wherein the curable resin (B) is an epoxy resin. The curable resin composition of Claim 3 in which curable resin (B) contains the hardening | curing agent for epoxy resins. The curable resin composition of Claim 3 or 4 in which curable resin (B) contains the hardening accelerator for epoxy resins. The adhesive agent containing the curable resin composition as described in any one of Claims 1-5 . The metal steel plate with which the curable resin composition as described in any one of Claims 1-5 was apply | coated. A curable resin cured product obtained by curing the curable resin composition according to any one of claims 1 to 5 .