JP2014141604A - Polymer fine particles-containing curable resin composition with improved storage stability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable resin composition with excellent storage stability, enabling the production of a cured product with excellent toughness and impact resistance.SOLUTION: A curable resin composition of the invention contains, with respect to 100 pts.mass of an epoxy resin (A), 1-100 pts.mass of polymer fine particles (B), and 1-100 pts.mass of colloid calcium carbonate (C), where the content of fumed silica (D) is less than 0.5 pts.mass.

Description

  The present invention relates to a curable resin composition having an epoxy resin as a main component and excellent in toughness and impact resistance.

Epoxy resin cured products are excellent in many respects such as dimensional stability, mechanical strength, electrical insulation properties, heat resistance, water resistance, and chemical resistance. However, cured products of epoxy resins have low fracture toughness and may exhibit very brittle properties, and such properties are often a problem in a wide range of applications.

  Patent Document 1 discloses a technique for improving toughness and impact resistance of a cured product obtained by dispersing polymer fine particles in a curable resin composition containing a curable resin such as an epoxy resin as a main component. ing.

  A technique for applying an epoxy resin composition having toughness and impact resistance to an adhesive or the like is disclosed in Patent Document 2 and the like. Generally, for the purpose of imparting thixotropy to such an epoxy resin composition, a fume is generally used. Dosilica is added.

  However, the epoxy resin composition containing polymer fine particles and fumed silica sometimes has insufficient storage stability.

WO2009-034966 WO2008-127923

  The present invention has been made in view of the above-mentioned circumstances, and the object of the present invention is storage stability without reducing the thixotropy of the curable resin composition excellent in toughness and impact resistance of the obtained cured product. Is to improve.

As a result of intensive studies to solve such problems, the present inventor,
In the curable resin composition containing the epoxy resin (A) and the polymer fine particles (B),
(A) Solving the said problem by making 1-100 mass parts colloidal calcium carbonate (C) with respect to 100 mass parts of component, and making fumed silica (D) less than 0.5 mass part. The present invention was completed.

That is, the present invention
A curable resin composition containing 1 to 100 parts by mass of polymer fine particles (B) and 1 to 100 parts by mass of colloidal calcium carbonate (C) with respect to 100 parts by mass of the epoxy resin (A),
The content of fumed silica (D) is less than 0.5 parts by mass, and relates to a curable resin composition.

  The number average particle diameter of the component (B) is preferably 10 to 2000 nm.

  The component (B) preferably has a core-shell structure.

  More preferably, the component (B) has at least one core layer selected from the group consisting of diene rubbers, (meth) acrylate rubbers, and organosiloxane rubbers.

  More preferably, the diene rubber is butadiene rubber and / or butadiene-styrene rubber.

  The component (B) has a shell layer obtained by graft polymerizing one or more monomer components selected from the group consisting of an aromatic vinyl monomer, a vinyl cyan monomer, and a (meth) acrylate monomer on the core layer. Further preferred.

  More preferably, the component (B) has a shell layer obtained by graft polymerization of a monomer component having an epoxy group to the core layer.

  The component (B) is preferably dispersed in the state of primary particles in the curable resin composition.

  The component (C) is preferably colloidal calcium carbonate treated with a fatty acid.

  (D) It is preferable not to contain a component.

  (A) It is preferable to contain 1-40 mass parts of epoxy hardening | curing agents (E) with respect to 100 mass parts of component.

  (A) It is preferable to contain 1-10 mass parts of hardening accelerators (F) with respect to 100 mass parts of components.

  Preferably, it is a one-pack type curable resin composition.

  The curable resin composition of the present invention can remarkably improve storage stability without reducing thixotropy.

  Hereinafter, the curable resin composition of the present invention will be described in detail.

<Epoxy resin (A)>
An epoxy resin (A) is used as a main component of the curable resin composition of the present invention.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, novolac type epoxy resin, and bisphenol A. Flame retardants such as glycidyl ether type epoxy resin of propylene oxide adduct, hydrogenated bisphenol A (or F) type epoxy resin, fluorinated epoxy resin, rubber-modified epoxy resin containing polybutadiene or NBR, glycidyl ether of tetrabromobisphenol A, etc. Type epoxy resin, p-oxybenzoic acid glycidyl ether ester type epoxy resin, m-aminophenol type epoxy resin, diaminodiphenylmethane series epoxy resin, Urethane-modified epoxy resin having a ethane bond, various alicyclic epoxy resins, N, N-diglycidylaniline, N, N-diglycidyl-o-toluidine, triglycidyl isocyanurate, polyalkylene glycol diglycidyl ether, glycerin, etc. Polyhydric alcohol glycidyl ether, hydantoin type epoxy resin, epoxidized product of unsaturated polymer such as petroleum resin, aminoglycidyl ether resin containing amino acid, bisphenol A (or F) or polybasic acid Examples include epoxy compounds obtained by addition reaction of, but not limited thereto, and generally used epoxy resins can be used. These epoxy resins may be used alone or in combination of two or more.

  Among these epoxy resins, those having at least two epoxy groups in one molecule are preferable from the viewpoint of high reactivity and easy formation of a three-dimensional network upon curing.

<Polymer fine particles (B)>
The curable resin composition of this invention uses 1-100 mass parts of polymer fine particles (B) with respect to 100 mass parts of (A) component. Due to the toughness improving effect of the component (B), the obtained cured product is excellent in toughness and crack resistance.

  From the balance of easy handling of the resulting curable resin composition and the toughness improving effect of the resulting cured product, the component (B) is preferably 2 to 70 parts by mass with respect to 100 parts by mass of the component (A). 50 mass parts is more preferable, and 4-20 mass parts is especially preferable.

  The particle diameter of the polymer fine particles is not particularly limited, but considering industrial productivity, the volume average particle diameter (Mv) is preferably 10 to 2000 nm, more preferably 30 to 600 nm, still more preferably 50 to 400 nm, and more preferably 100 to 200 nm. Is particularly preferred. The volume average particle diameter (Mv) of the polymer particles can be measured using Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.).

  The component (B) is preferably dispersed in the state of primary particles in the curable resin composition. In the present invention, “the polymer fine particles are dispersed in the state of primary particles in the curable resin composition” (hereinafter also referred to as primary dispersion) means that the polymer fine particles are substantially independent (contacted). The dispersion state is such that, for example, a part of the curable resin composition is dissolved in a solvent such as methyl ethyl ketone, and the particle size is measured by a particle size measuring device using laser light scattering. It can be confirmed by measuring.

  In addition, “stable dispersion” of polymer fine particles means that the polymer fine particles are not aggregated, separated, or precipitated in the continuous layer, and are constantly under normal conditions over a long period of time. Mean that the distribution of the polymer fine particles in the continuous layer does not substantially change, and the viscosity is lowered by heating these compositions in a range that is not dangerous. It is preferable that “stable dispersion” can be maintained even if stirring is performed.

  (B) A component may be used independently and may be used together 2 or more types.

  The structure of the polymer fine particle is not particularly limited, but preferably has a core-shell structure of two or more layers. It is also possible to have a structure of three or more layers constituted by an intermediate layer covering the core layer and a shell layer further covering the intermediate layer.

  Hereinafter, each layer will be specifically described.

≪Core layer≫
The core layer is preferably an elastic core layer having properties as a rubber in order to increase the toughness of the cured product of the curable resin composition of the present invention. In order to have properties as rubber, the elastic core layer of the present invention preferably has a gel content of 60% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. It is preferably 95% by mass or more. In addition, the gel content referred to in the present specification means that 0.5 g of crumb obtained by coagulation and drying is immersed in 100 g of toluene and left to stand at 23 ° C. for 24 hours, and then insoluble and soluble components are separated. The ratio of insoluble matter to the total amount of insoluble matter and soluble matter is meant. The core layer preferably has a glass transition temperature of 23 ° C. or lower.

  As a polymer capable of forming an elastic core layer having properties as a rubber, at least one monomer (first monomer) selected from natural rubber, diene monomers (conjugated diene monomers) and (meth) acrylate monomers is used. Rubber elastic body comprising 50 to 100 mass% of the above and 0 to 50 mass% of other copolymerizable vinyl monomer (second monomer), polysiloxane rubber elastic body, or a combination thereof Things. From the viewpoint of the effect of improving the toughness of the resulting cured product, a diene rubber using a diene monomer is preferred. Since a wide variety of polymer designs are possible by combining various monomers, (meth) acrylate rubber is preferred. Moreover, when it is going to improve the impact resistance in low temperature, without reducing the heat resistance of hardened | cured material, it is preferable that an elastic core layer is a polysiloxane rubber-type elastic body. In the present invention, (meth) acrylate means acrylate and / or methacrylate.

  Examples of the monomer (conjugated diene monomer) constituting the diene rubber used for the elastic core layer include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, 2-methyl-1,3-butadiene. Etc. These diene monomers may be used alone or in combination of two or more.

  From the viewpoint of the effect of improving toughness, butadiene rubber using 1,3-butadiene or butadiene-styrene rubber which is a copolymer of 1,3-butadiene and styrene is preferable, and butadiene rubber is more preferable. Also, butadiene-styrene rubber is more preferred because it can increase the transparency of the cured product obtained by adjusting the refractive index.

  Moreover, as a monomer which comprises the (meth) acrylate type rubber | gum used for an elastic core layer, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl ( Alkyl (meth) acrylates such as meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, and behenyl (meth) acrylate; aromatic ring containing (meth) such as phenoxyethyl (meth) acrylate and benzyl (meth) acrylate Acrylates; hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate; glycidyl (meth) acrylate, glycidylalkyl (meth) acrylate Glycidyl (meth) acrylates such as alkoxide; alkoxyalkyl (meth) acrylates; allylalkyl (meth) acrylates such as allyl (meth) acrylate and allylalkyl (meth) acrylate; monoethylene glycol di (meth) acrylate, Examples include polyfunctional (meth) acrylates such as triethylene glycol di (meth) acrylate and tetraethylene glycol di (meth) acrylate. These (meth) acrylate monomers may be used alone or in combination of two or more. Particularly preferred are ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate.

  Examples of the vinyl monomer (second monomer) copolymerizable with the first monomer include vinyl arenes such as styrene, α-methyl styrene, monochlorostyrene and dichlorostyrene; vinyl carboxylic acids such as acrylic acid and methacrylic acid. Vinyl vinyls such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride, vinyl bromide and chloroprene; vinyl acetate; alkenes such as ethylene, propylene, butylene and isobutylene; diallyl phthalate, triallyl cyanurate, And polyfunctional monomers such as triallyl isocyanurate and divinylbenzene. These vinyl monomers may be used alone or in combination of two or more. Particularly preferred is styrene.

  Examples of the polysiloxane rubber-based elastic body that can constitute the elastic core layer include alkyl or aryl such as dimethylsilyloxy, diethylsilyloxy, methylphenylsilyloxy, diphenylsilyloxy, dimethylsilyloxy-diphenylsilyloxy, and the like. Polysiloxane polymers composed of alkyl or aryl 1-substituted silyloxy units, such as polysiloxane polymers composed of disubstituted silyloxy units, and organohydrogensilyloxy in which part of the alkyl in the side chain is substituted with hydrogen atoms Polymers. These polysiloxane polymers may be used alone or in combination of two or more. Among them, dimethylsilyloxy, methylphenylsilyloxy, dimethylsilyloxy-diphenylsilyloxy are preferable for imparting heat resistance to the cured product, and dimethylsilyloxy is most preferable because it is easily available and economical.

  In an embodiment in which the elastic core layer is formed from a polysiloxane rubber-based elastic body, the polysiloxane-based polymer portion is 80% by mass or more (more preferably), assuming that the entire elastic body is 100% by mass so as not to impair the heat resistance of the cured product. Is preferably 90% by mass or more).

  From the viewpoint of maintaining the dispersion stability of the polymer fine particles in the curable resin composition, the core layer preferably has a cross-linked structure introduced into a polymer component obtained by polymerizing the monomer or a polysiloxane polymer component. . As a method for introducing a crosslinked structure, a generally used method can be employed. For example, as a method for introducing a cross-linked structure into a polymer component obtained by polymerizing the above monomer, a method in which a cross-linkable monomer such as a polyfunctional monomer or a mercapto group-containing compound is added to the polymer component and then polymerized is exemplified. . In addition, as a method for introducing a crosslinked structure into the polysiloxane polymer, a method in which a polyfunctional alkoxysilane compound is partially used at the time of polymerization, or a reactive group such as a vinyl reactive group or a mercapto group is added to the polysiloxane polymer. And then adding a vinyl polymerizable monomer or an organic peroxide to cause a radical reaction, or adding a crosslinkable monomer such as a polyfunctional monomer or a mercapto group-containing compound to the polysiloxane polymer, Next, a polymerization method and the like can be mentioned.

  As the polyfunctional monomer, butadiene is not included, and allylalkyl (meth) acrylates such as allyl (meth) acrylate and allylalkyl (meth) acrylate; allyloxyalkyl (meth) acrylates; (poly) ethylene glycol di It has two or more (meth) acryl groups such as (meth) acrylate, butanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetraethylene glycol di (meth) acrylate. Polyfunctional (meth) acrylates; diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene and the like. Particularly preferred are allyl methacrylate, triallyl isocyanurate, butanediol di (meth) acrylate, and divinylbenzene.

  In the present invention, the glass transition temperature of the core layer (hereinafter sometimes simply referred to as “Tg”) is preferably 0 ° C. or lower, more preferably −20 ° C. or lower, still more preferably −40 ° C. or lower, A temperature of 60 ° C. or lower is particularly preferable.

  Further, the volume average particle diameter of the core layer is preferably 0.03 to 2 μm, more preferably 0.05 to 1 μm. In many cases, it is difficult to stably obtain a volume average particle size of less than 0.03 μm, and when it exceeds 2 μm, the heat resistance and impact resistance of the final molded product may be deteriorated. The volume average particle diameter can be measured using Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.).

  The core layer is preferably 40 to 97% by mass, more preferably 60 to 95% by mass, still more preferably 70 to 93% by mass, and particularly preferably 80 to 90% by mass based on 100% by mass of the entire polymer particles. If the core layer is less than 40% by mass, the effect of improving the toughness of the cured product may be reduced. If the core layer is larger than 97% by mass, the polymer fine particles are likely to aggregate, and the curable resin composition has a high viscosity and may be difficult to handle.

  In the present invention, the core layer often has a single layer structure, but may have a multilayer structure. When the core layer has a multilayer structure, the polymer composition of each layer may be different.

≪Middle layer≫
In the present invention, an intermediate layer may be formed if necessary. In particular, the following rubber surface cross-linked layer may be formed as the intermediate layer.

  The rubber surface cross-linking layer polymerizes rubber surface cross-linking layer components composed of 30 to 100% by weight of a polyfunctional monomer having two or more radical double bonds in the same molecule and 0 to 70% by weight of other vinyl monomers. And having the effect of reducing the viscosity of the curable resin composition of the present invention and the effect of improving the dispersibility of the polymer fine particles (B) in the component (A). It also has the effect of increasing the crosslinking density of the core layer and increasing the grafting efficiency of the shell layer.

  Specific examples of the polyfunctional monomer include the same monomers as the above-mentioned polyfunctional monomer, but acryl methacrylate and triallyl isocyanurate are preferable.

≪Shell layer≫
The outermost shell layer of the polymer fine particles is obtained by polymerizing a shell-forming monomer. According to the present invention, the compatibility between the polymer fine particles and the component (A) is improved, and the curing of the present invention is performed. It consists of a shell polymer which plays the role which makes it possible to disperse | distribute a polymer fine particle in the state of a primary particle in the functional resin composition or its hardened | cured material.

  Such a shell polymer is preferably grafted to the core layer. More precisely, it is preferable that the monomer component used for forming the shell layer is graft-polymerized to the core polymer forming the core layer, and the shell polymer layer and the rubber core are substantially chemically bonded. That is, preferably, the shell polymer is formed by graft polymerization of the shell-forming monomer in the presence of the core polymer, and in this way, the core polymer is graft-polymerized. Covers a part or the whole. This polymerization operation can be carried out by adding a monomer, which is a constituent of the shell polymer, to the core polymer latex prepared and present in the form of an aqueous polymer latex.

  As the monomer for forming the shell layer, for example, aromatic vinyl monomer, vinyl cyan monomer, and (meth) acrylate monomer are preferable from the viewpoint of compatibility and dispersibility in the curable resin composition of component (B). More preferred are (meth) acrylate monomers.

  In order to maintain a good dispersion state without aggregation of the component (B) in the cured product or polymer, from the viewpoint of chemically bonding with the component (A), as a monomer for forming the shell layer, an epoxy group, an oxetane group, Reactive group-containing monomer containing at least one selected from the group consisting of hydroxyl group, amino group, imide group, carboxylic acid group, carboxylic anhydride group, cyclic ester, cyclic amide, benzoxazine group, and cyanate ester group Is preferable, and a monomer having an epoxy group is preferable.

  Further, when a multifunctional monomer having two or more double bonds is used as the shell layer forming monomer, swelling of the polymer fine particles in the curable resin composition is prevented, and the viscosity of the curable resin composition is reduced. It is preferable because it tends to be low and handleability is improved.

  The polyfunctional monomer is preferably contained in 1 to 20% by weight, more preferably 5 to 15% by weight, in 100% by weight of the shell-forming monomer.

  Specific examples of the aromatic vinyl monomer include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, and the like.

  Specific examples of the vinylcyan monomer include acrylonitrile and methacrylonitrile.

  Specific examples of the (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, and the like.

  Specific examples of the monomer having an epoxy group include glycidyl (meth) acrylate.

  Specific examples of the polyfunctional monomer having two or more double bonds include the same monomers as the above-mentioned polyfunctional monomer, and acryl methacrylate and triallyl isocyanurate are preferable.

  In the present invention, for example, a shell layer which is a polymer of a monomer for shell formation in which 0 to 50% by mass of styrene, 0 to 50% by mass of acrylonitrile, 0 to 100% by mass of methyl methacrylate, and 0 to 50% by mass of glycidyl methacrylate are combined. It is preferable to do. Thereby, a desired toughness improving effect and mechanical properties can be realized in a well-balanced manner. In particular, it is considered that the inclusion of glycidyl methacrylate as a constituent component improves the interfacial adhesion with the component (A).

  These monomer components may be used alone or in combination of two or more.

  The shell layer may be formed including other monomer components in addition to the monomer components.

  The graft ratio of the shell layer is preferably 70% or more (more preferably 80% or more, and further 90% or more). When the graft ratio is less than 70%, the viscosity of the liquid resin composition may increase. In the present specification, the method for calculating the graft ratio is as follows.

  First, an aqueous latex containing polymer fine particles was coagulated and dehydrated, and finally dried to obtain polymer fine particle powder. Next, 2 g of the polymer fine particle powder was immersed in 100 g of methyl ethyl ketone (MEK) at 23 ° C. for 24 hours, and then the MEK soluble component was separated from the MEK insoluble component, and the methanol insoluble component was further separated from the MEK soluble component. And it calculated by calculating | requiring the ratio of MEK insoluble content with respect to the total amount of MEK insoluble content and methanol insoluble content.

≪Method for producing polymer fine particles≫
(Manufacturing method of core layer)
The polymer forming the core layer constituting the polymer fine particle used in the present invention comprises at least one monomer (first monomer) selected from diene monomers (conjugated diene monomers) and (meth) acrylate monomers. In this case, the core layer can be formed, for example, by emulsion polymerization, suspension polymerization, microsuspension polymerization, or the like, and for example, the method described in WO2005 / 028546 can be used.

  In addition, when the polymer forming the core layer is configured to include a polysiloxane polymer, the formation of the core layer can be produced by, for example, emulsion polymerization, suspension polymerization, microsuspension polymerization, etc. The method described in WO2006 / 070664 can be used.

(Method for forming shell layer and intermediate layer)
The intermediate layer can be formed by polymerizing the monomer for forming the intermediate layer by a known radical polymerization. When the rubber elastic body constituting the core layer is obtained as an emulsion, the polymerization of the monomer having two or more double bonds is preferably carried out by an emulsion polymerization method.

  The shell layer can be formed by polymerizing a shell layer forming monomer by known radical polymerization. When the polymer layer precursor formed by coating the core layer or the core layer with an intermediate layer is obtained as an emulsion, the polymerization of the monomer for forming the shell layer is preferably performed by an emulsion polymerization method, for example, WO2005 Can be produced according to the method described in Japanese Patent No.

  As an emulsifier (dispersant) that can be used in emulsion polymerization, alkyl or aryl sulfonic acid represented by dioctylsulfosuccinic acid and dodecylbenzenesulfonic acid, alkyl or arylether sulfonic acid, alkyl or aryl represented by dodecylsulfuric acid, and the like. Sulfuric acid, alkyl or aryl ether sulfuric acid, alkyl or aryl substituted phosphoric acid, alkyl or aryl ether substituted phosphoric acid, N-alkyl or aryl sarcosine acid represented by dodecyl sarcosine acid, alkyl represented by oleic acid or stearic acid, or Various acids such as aryl carboxylic acids, alkyl or aryl ether carboxylic acids, anionic emulsifiers (dispersants) such as alkali metal salts or ammonium salts of these acids; Nonionic emulsifiers such as-substituted polyethylene glycol (dispersing agent); polyvinyl alcohol, alkyl substituted cellulose, polyvinyl pyrrolidone, dispersants such as polyacrylic acid derivatives. These emulsifiers (dispersants) may be used alone or in combination of two or more.

  As long as the dispersion stability of the aqueous latex of polymer particles is not hindered, it is preferable to reduce the amount of emulsifier (dispersant) used. Moreover, an emulsifier (dispersant) is so preferable that the water solubility is high. If the water solubility is high, the emulsifier (dispersant) can be easily removed by washing with water, and adverse effects on the finally obtained cured product can be easily prevented.

  When the emulsion polymerization method is employed, a known initiator, that is, 2,2′-azobisisobutyronitrile, hydrogen peroxide, potassium persulfate, ammonium persulfate, or the like can be used as the thermal decomposition type initiator. .

  In addition, organic peroxides such as t-butylperoxyisopropyl carbonate, paramentane hydroperoxide, cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-hexyl peroxide, etc. Oxides; peroxides such as inorganic peroxides such as hydrogen peroxide, potassium persulfate, and ammonium persulfate; reducing agents such as sodium formaldehyde sulfoxylate and glucose as necessary; and iron sulfate (II as necessary) ), A chelating agent such as disodium ethylenediaminetetraacetate if necessary, and a redox type initiator using a phosphorus-containing compound such as sodium pyrophosphate if necessary.

  When a redox type initiator system is used, the polymerization can be performed at a low temperature at which the peroxide is not substantially thermally decomposed, and the polymerization temperature can be set in a wide range, which is preferable. Of these, organic peroxides such as cumene hydroperoxide, dicumyl peroxide, and t-butyl hydroperoxide are preferably used as the redox initiator. When the amount of the initiator used, or the redox type initiator is used, the amount of the reducing agent / transition metal salt / chelating agent used may be within a known range. In the polymerization of a monomer having two or more double bonds, a known chain transfer agent can be used within a known range. In addition, a surfactant can be used, but this is also within a known range.

  The polymerization temperature, pressure, deoxygenation, and other conditions during the polymerization can be within the known ranges. The polymerization of the intermediate layer forming monomer may be performed in one stage or in two or more stages. For example, in addition to a method of adding an intermediate layer forming monomer to a rubber elastic emulsion constituting the elastic core layer at once, a method of continuously adding it, an elastic core layer is added to a reactor in which an intermediate layer forming monomer is charged in advance. For example, a method of carrying out polymerization after adding an emulsion of a rubber elastic body to be constituted can be employed.

<Colloidal calcium carbonate (C)>
It is essential that the curable resin composition of the present invention contains 1 to 100 parts by mass of colloidal calcium carbonate (C) with respect to 100 parts by mass of the component (A).

  (C) A component raises the viscosity of the curable resin composition of this application, and provides thixotropy. Further, even when combined with the components (A) and (B) of the present application, the storage stability is not adversely affected.

  The component (C) is generally calcium carbonate of uniform particles produced by reacting carbon dioxide with lime milk obtained by adding water to quick lime, such as “precipitated calcium carbonate” and “colloidal calcium carbonate”. Alternatively, it may be called “synthetic calcium carbonate”.

  Component (C) is preferably surface-treated from the viewpoint of dispersibility in component (A), and more preferably surface-treated with fatty acids such as saturated fatty acids and unsaturated fatty acids and resin acids. From the viewpoint of storage stability of the resulting curable composition, those surface-treated with saturated fatty acids or unsaturated fatty acids are more preferred, and those surface-treated with unsaturated fatty acids are particularly preferred.

  Although the average particle diameter of (C) component is not restrict | limited in particular, 0.03-0.3 micrometer is preferable, 0.05-0.2 micrometer is more preferable, 0.07-0.15 micrometer is still more preferable.

  The amount of component (C) used is preferably 5 to 70 parts by weight, more preferably 10 to 50 parts by weight, still more preferably 15 to 40 parts by weight, with respect to 100 parts by weight of component (A). Part is particularly preferred. If it is less than 1 part by mass, the thixotropy imparting effect may not be sufficient, and if it exceeds 100 parts by mass, the curable composition may have a high viscosity and may be difficult to handle.

  (C) A component may be used independently and may be used together 2 or more types.

<Fumed silica (D)>
In the curable resin composition of the present invention, it is essential that the content of fumed silica (D) is less than 0.5 parts by mass with respect to 100 parts by mass of component (A).

  (D) A component raises the viscosity of the curable resin composition of this application, and provides thixotropy. However, it has been found that the storage stability decreases when combined with the components (A) and (B) of the present application.

  The amount of component (D) used is preferably less than 0.3 parts by weight, more preferably less than 0.1 parts by weight, even more preferably less than 0.01 parts by weight, relative to 100 parts by weight of component (A). It is particularly preferable not to contain the component D). If it is 0.5 parts by mass or more, the storage stability of the curable resin composition of the present application may be poor and difficult to handle.

  The component (D) is generally silica fine particles produced by burning silicon chloride such as silicon tetrachloride gas in a gas phase.

  The component (D) is composed of primary particles having a spherical shape and no pores, and aggregated particles and agglomerated particles that are strongly aggregated in the manufacturing process are formed. Siloxane and silanol groups are present on the surface of these particles, and hydrophobicity is imparted by chemically reacting silanes or silazanes with the silanol groups. Specific examples of the surface treatment agent include dimethyldichlorosilane, silicone oil, hexamethyldisilazane, octylsilane, hexadecylsilane, aminosilane, methacrylsilane, octamethylcyclotetrasiloxane, and polydimethylsiloxane. . It becomes easy to disperse | distribute to (A) component by hydrophobizing the surface. From the viewpoint of dispersibility in the component (A), it is preferable to perform surface treatment with polydimethylsiloxane.

  The particle diameter of the component (D) is not particularly limited, but the specific surface area (according to the BET adsorption method) is preferably 10 m2 / g or more, more preferably 30 to 500 m2 / g, still more preferably about 50 to 300 m2 / g. Ultrafine silica is preferred. The BET adsorption method is a method in which an inert gas molecule whose adsorption occupation area is known is physically adsorbed on the surface of powder particles at the temperature of liquid nitrogen, and the specific surface area of the sample is obtained from the amount.

  (D) A component may be used independently and may be used together 2 or more types.

<Filler other than (C) component and (D) component>
In this invention, fillers other than (C) component and (D) component can be included to such an extent that the effect of this invention is not reduced.

  Specific examples of fillers include reinforcing fillers such as precipitated silica, crystalline silica, fused silica, dolomite, anhydrous silicic acid, hydrous silicic acid, and carbon black; heavy calcium carbonate, magnesium carbonate, diatomaceous earth, Firing clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, aluminum fine powder, flint powder, zinc oxide, activated zinc white, shirasu balloon, glass microballoon, asbestos, glass fibers and filaments such as filaments And the like.

<Epoxy resin curing agent (E)>
In this invention, an epoxy resin hardening | curing agent (E) can be used as needed.

  When the curable resin composition of the present invention is used as a one-component adhesive, the component (E) is selected so that the adhesive quickly cures when heated to a temperature of 80 ° C. or higher, preferably 140 ° C. or higher. Is preferred. On the contrary, it is preferable to select the component (E) and the component (F) described later so that the curing is very slow even at room temperature (about 22 ° C.) or at least up to 50 ° C.

  Examples of the component (E) include boron trichloride / amine complex, boron trifluoride / amine complex, dicyandiamide, melamine, diallyl melamine, guanamine (for example, acetoguanamine and benzoguanamine), aminotriazole (for example, 3-amino- 1,2,4-triazole), hydrazides (for example, adipic acid dihydrazide, stearic acid dihydrazide, isophthalic acid dihydrazide, semicarbazide), cyanoacetamide, and aromatic polyamines (for example, diaminodiphenylsulfone). It is more preferable to use dicyandiamide, isophthalic acid dihydrazide, adipic acid dihydrazide, or 4,4'-diaminodiphenylsulfone, and dicyandiamide is particularly preferable.

  Among the above curing agents, the latent epoxy curing agent is preferable because the curable resin composition of the present invention can be made into one component.

  (E) A component may be used independently and may be used together 2 or more types.

The component (E) is used in an amount sufficient to cure the composition. Typically, sufficient curing agent is provided to consume at least 80% of the epoxide groups present in the composition. A large excess over that required for consumption of epoxide groups is usually not necessary. (E) The usage-amount of a component is preferable 1-40 mass parts with respect to 100 mass parts of (A) component, 2-30 mass parts is more preferable, 3-25 mass parts is still more preferable, 5-20 mass Part is particularly preferred. If it is less than 1 mass part, the sclerosis | hardenability of the curable resin composition of this application may worsen. If the amount is more than 40 parts by mass, the storage stability of the curable resin composition of the present application may be poor and difficult to handle.
<Curing agent accelerator (F)>
In this invention, a hardening accelerator (F) can be used as needed.

  The component (F) is a catalyst for accelerating the reaction between the epoxy group and the epoxide reactive group on the other component of the curing agent or adhesive.

  As the component (F), ureas such as p-chlorophenyl-N, N-dimethylurea (Monuron), 3-phenyl-1,1-dimethylurea (Phenuron), 3,4-dichlorophenyl-N, N- Dimethylurea (Diuron), N- (3-chloro-4-methylphenyl) -N ', N'-dimethylurea (Chlortoluron), tert-acryl- or alkyleneamines such as benzyldimethylamine, 2,4,6 -Tris (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol incorporated in a poly (p-vinylphenol) matrix, piperidine or derivatives thereof, imidazole derivatives, generally C1-C12 alkylene imidazoles Or N-arylimidazo Le, for example, 2-ethyl-2-methylimidazole or N- butyl imidazole, 6-caprolactam, and the like. The catalyst may be encapsulated or may be a potential one that becomes active only when the temperature is raised.

  (F) A component may be used independently and may be used together 2 or more types.

(F) As for the usage-amount of a component, 0.1-10 mass parts is preferable with respect to 100 mass parts of (A) component, 0.2-5 mass parts is more preferable, 0.5-3 mass parts is further. 0.8 to 2 parts by mass is preferable. If it is less than 0.1 mass part, the sclerosis | hardenability of the curable resin composition of this application may worsen. When the amount is more than 10 parts by mass, the storage stability of the curable resin composition of the present application may be poor and difficult to handle.
<Other ingredients>
In this invention, another compounding component can be used as needed. Other ingredients include dehydrating agents such as calcium oxide, colorants such as pigments and dyes, extender pigments, UV absorbers, antioxidants, stabilizers (anti-gelling agents), plasticizers, leveling agents, anti-oxidants. Examples include foaming agents, silane coupling agents, antistatic agents, flame retardants, lubricants, viscosity reducers, low shrinkage agents, organic fillers, thermoplastic resins, drying agents, and dispersing agents.
<Method for producing curable resin composition>
The curable resin composition of the present invention is a composition containing polymer fine particles (B) in the curable resin composition containing the component (A) as a main component, preferably the polymer fine particles (B) are 1 It is a composition dispersed in the form of secondary particles.

  Various methods can be used to obtain such a composition in which the polymer fine particles (B) are dispersed in the form of primary particles. For example, polymer fine particles obtained in an aqueous latex state can be used as the component (A). Examples include a method of removing unnecessary components such as water after contact, a method of once extracting polymer fine particles into an organic solvent and then mixing with the component (A), and then removing the organic solvent. International Publication WO2005 / It is preferable to use the method described in 28546. The specific production method is as follows: an aqueous latex containing polymer fine particles (B) (specifically, a reaction mixture after producing polymer fine particles by emulsion polymerization) has a solubility in water at 20 ° C. of 5% by mass. After mixing with an organic solvent of 40% by mass or less and further mixing with excess water, the first step of aggregating the polymer particles, and separating and collecting the agglomerated polymer fine particles (B) from the liquid phase, A second step of mixing with an organic solvent to obtain an organic solvent solution of the polymer fine particles (B), and a third step of further distilling off the organic solvent after further mixing the organic solvent solution with the component (A). It is preferable to be prepared by.

  The component (A) is preferably liquid at 23 ° C. because the third step becomes easy. “Liquid at 23 ° C.” means that the softening point is 23 ° C. or lower, and indicates fluidity at 23 ° C.

  In the composition obtained by performing the above-described steps, in which the polymer fine particles (B) are dispersed in the state of primary particles in the component (A), the components (A), (C), (D), (E) The curable resin composition of the present invention in which the polymer fine particles (B) are dispersed in the state of primary particles by further mixing the components, the component (F), and the above-described other compounding components as necessary. Is obtained.

<Hardened product>
The present invention includes a cured product obtained by curing the curable resin composition. In the curable resin composition of the present invention, the polymer fine particles are dispersed in the form of primary particles. Therefore, by curing the polymer fine particles, a cured product in which the polymer fine particles are uniformly dispersed can be easily obtained. In addition, since the polymer fine particles hardly swell and the viscosity of the curable resin composition is low, a cured product can be obtained with good workability.

<Application>
The composition of the present invention is preferably a one-component curable resin composition from the viewpoint of handleability.

  The composition of the present invention is preferably used for applications such as adhesives such as structural adhesives, paints, materials for lamination with glass fibers, printed wiring boards, and electrical insulating materials.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these, and can be implemented with appropriate modifications within a range that can meet the gist of the preceding and following descriptions. These are all included in the technical scope of the present invention. In the following Examples and Comparative Examples, “parts” and “%” mean parts by mass or mass%.

Evaluation method First, the evaluation method of the curable resin composition manufactured by the Example and the comparative example is demonstrated below.

[1] Measurement of average particle diameter The volume average particle diameter (Mv) of the polymer particles dispersed in the aqueous latex was measured using Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.). A sample diluted with deionized water was used as a measurement sample. For measurement, enter the refractive index of water or methyl ethyl ketone and the refractive index of each polymer particle, and adjust the sample concentration so that the measurement time is 600 seconds and the Signal Level is in the range of 0.6 to 0.8. I went.

[2] Measurement of viscosity The viscosity of the curable resin composition was measured using a digital viscometer DV-II + Pro type manufactured by BROOKFIELD. Measurement was performed at 23 ° C. using a spindle CPE-52.

1. Formation of Core Layer Production Example 1-1; Preparation of Polybutadiene Rubber Latex (R-1) In a 100 L pressure-resistant polymerization machine, 200 parts by mass of deionized water, 0.03 parts by mass of tripotassium phosphate, potassium dihydrogen phosphate 0 .25 parts by mass, disodium ethylenediaminetetraacetate (EDTA) 0.002 parts by mass, ferrous sulfate heptahydrate (Fe) 0.001 parts by mass and sodium dodecylbenzenesulfonate (SDS) 1.5 parts by mass Was added, nitrogen was sufficiently substituted while stirring to remove oxygen, and 100 parts by mass of butadiene (BD) was added to the system, and the temperature was raised to 45 ° C. Polymerization was initiated by adding 0.015 parts by mass of paramentane hydroperoxide (PHP) and then 0.04 parts by mass of sodium formaldehyde sulfoxylate (SFS). Four hours after the start of polymerization, 0.01 parts by weight of PHP, 0.0015 parts by weight of EDTA and 0.001 parts by weight of Fe were added. At 10 hours after polymerization, the residual monomer was removed by devolatilization under reduced pressure to complete the polymerization, and latex (R-1) containing polybutadiene rubber particles was obtained. The volume average particle diameter of the polybutadiene rubber particles contained in the obtained latex was 0.10 μm.

2. Preparation of polymer fine particles (formation of shell layer)
Production Example 2-1: Preparation of Core-Shell Polymer Latex (L-1) In a 3 L glass container, 1575 parts by mass of latex (R-1) obtained in Production Example 1-1 (equivalent to 510 parts by mass of polybutadiene rubber particles) and deionized 315 parts by mass of water was charged and stirred at 60 ° C. while performing nitrogen substitution. After adding 0.024 parts by mass of EDTA, 0.006 parts by mass of Fe, and 1.2 parts by mass of SFS, a graft monomer (40 parts by mass of styrene (ST), 20 parts by mass of acrylonitrile (AN), 30 parts by mass of glycidyl methacrylate (GMA)) , And a mixture of 0.3 part by mass of cumene hydroperoxide (CHP) was continuously added over 2 hours for graft polymerization. After completion of the addition, the reaction was terminated by further stirring for 2 hours to obtain a core-shell polymer latex (L-1). The volume average particle diameter of the core-shell polymer contained in the obtained latex was 0.11 μm.

3. Preparation of dispersion in which polymer fine particles (B) are dispersed in a curable resin Production Example 3-1; Preparation of dispersion (M-1) 132 g of methyl ethyl ketone (MEK) is introduced into a 1 L mixing tank at 25 ° C. and stirred. However, 132 g (corresponding to 40 g of polymer fine particles) of the core-shell polymer aqueous latex (L-1 to L-4) obtained in Production Examples 2-1 to 2-4 was charged. After mixing uniformly, 200 g of water was added at a feed rate of 80 g / min. When the stirring was stopped immediately after the completion of the supply, a slurry liquid composed of an aqueous phase partially containing a floating aggregate and an organic solvent was obtained. Next, an agglomerate containing a part of the aqueous phase was left, and 360 g of the aqueous phase was discharged from the discharge port at the bottom of the tank. 90 g of MEK was added to the obtained aggregate and mixed uniformly to obtain a dispersion in which the core-shell polymer was uniformly dispersed. To this dispersion, 120 g of epoxy resin (A-1: manufactured by Mitsubishi Chemical Corporation, JER828EL) as component (A) was mixed. From this mixture, MEK was removed with a rotary evaporator. Thus, a dispersion (M-1) in which polymer fine particles were dispersed in an epoxy resin was obtained.

(Examples 1-8, Comparative Examples 1-6)
According to the formulation shown in Table 1, the epoxy resin (A-1) as the component (A), the dispersion (M-1) obtained in Production Example 3-1, and the colloidal calcium carbonate as the component (C), Heavy calcium carbonate and (D) component fumed silica were weighed and mixed well to obtain a curable resin composition. Before and after storing this composition at 40 ° C. for 7 days, the viscosities at Shear Rate 1 (s ⁻¹ ) and 5 (s ⁻¹ ) were measured. The thixotropy was evaluated from “viscosity of 1 (s ⁻¹ ) before storage / viscosity of 5 (s ⁻¹ ) before storage”. The larger this value, the better the thixotropy. The storage stability was evaluated from “viscosity of 5 (s ⁻¹ ) after storage / viscosity of 5 (s ⁻¹ ) before storage”. The larger this value, the worse the storage stability. The test results are shown in Table 1.

  In addition, what was shown below was used for the various compounding agents in Table 1.

<Colloidal calcium carbonate (C)>
Shiraka Hana CCR (manufactured by Shiraishi Kogyo, colloidal calcium carbonate surface-treated with saturated fatty acids)
Shiraka Hana CCR-S (manufactured by Shiraishi Kogyo Co., Ltd., colloidal calcium carbonate surface-treated with unsaturated fatty acid)

<Heavy calcium carbonate>
Whiteon SB (Shiraishi calcium, untreated heavy calcium carbonate)

<Fumed silica (D)>
CAB-O-SIL TS-720 (manufactured by CABOT, fumed silica surface-treated with polydimethylsiloxane),
HDK H18 (manufactured by WACKER, fumed silica surface-treated with polydimethylsiloxane),
Aerosil 130 (manufactured by EVONIK, untreated fumed silica),

  From Table 1, it can be seen that the curable resin composition of the present invention has high thixotropy and good storage stability (small change in viscosity).

Claims (13)

A curable resin composition containing 1 to 100 parts by mass of polymer fine particles (B) and 1 to 100 parts by mass of colloidal calcium carbonate (C) with respect to 100 parts by mass of the epoxy resin (A),
Content of fumed silica (D) is less than 0.5 mass part, The curable resin composition characterized by the above-mentioned. (B) The number average particle diameter of a component is 10-2000 nm, The curable resin composition of Claim 1 characterized by the above-mentioned. The curable resin composition according to claim 1, wherein the component (B) has a core-shell structure. The component (B) has one or more core layers selected from the group consisting of diene rubbers, (meth) acrylate rubbers, and organosiloxane rubbers. Resin composition. The curable resin composition according to claim 4, wherein the diene rubber is butadiene rubber and / or butadiene-styrene rubber. The component (B) has a shell layer obtained by graft polymerization of at least one monomer component selected from the group consisting of an aromatic vinyl monomer, a vinyl cyan monomer, and a (meth) acrylate monomer on the core layer. The curable resin composition according to claim 3, wherein the curable resin composition is a curable resin composition. The curable resin composition according to any one of claims 3 to 6, wherein the component (B) has a shell layer obtained by graft polymerization of a monomer component having an epoxy group to the core layer. The curable resin composition according to any one of claims 1 to 7, wherein the component (B) is dispersed in the state of primary particles in the curable resin composition. The curable resin composition according to any one of claims 1 to 8, wherein the component (C) is colloidal calcium carbonate treated with a fatty acid. (D) Component is not contained, The curable resin composition in any one of Claim 1 to 9 characterized by the above-mentioned. The curable resin composition according to any one of claims 1 to 10, further comprising 1 to 40 parts by mass of an epoxy curing agent (E) with respect to 100 parts by mass of the component (A). The curable resin composition according to any one of claims 1 to 11, further comprising 1 to 10 parts by mass of a curing accelerator (F) with respect to 100 parts by mass of the component (A). The one-component curable resin composition according to any one of claims 1 to 12.