WO2023033076A1 - Adhesive composition - Google Patents

Abstract

Provided is an adhesive composition having both a high adhesion strength and an improved cohesive failure rate.　The adhesive composition comprises a heat-curable resin [referred to as component (A)], thermoplastic-resin particles [referred to as component (B)], and a hardener and/or a hardening accelerator [inclusively referred to as component (C); the hardener is referred to as component (C-1) and the hardening accelerator as component (C-2)], wherein the component (B) is thermoplastic-resin particles which, when examined as a no. 7 dumbbell specimen having a width of 2 mm and a thickness of 1 mm formed in accordance with JIS K7161, have a tensile modulus of 1 GPa or less and which have a strain energy per unit volume, as obtained from a stress-strain curve of the specimen, of 20,000 kJ/m³ or greater.

Description

adhesive composition

The present invention relates to adhesive compositions.

Conventionally, various adhesive compositions have been used in various industrial fields such as automobiles and electronic materials. Adhesive compositions used in the industrial field are required to have stable adhesion performance in addition to high adhesive strength to objects to be adhered such as metal materials. Stable adhesion performance specifically means that the failure mode when breaking by applying an external force after bonding is cohesive failure, and that the failure mode is interfacial failure. There is a problem that the adhesion performance is not stable because the external force when peeling occurs at the interface with the object varies greatly. (Patent document 1)

As a technique for making the failure mode at the time of failure cohesive failure, the above-mentioned Patent Document 1 discloses an adhesive composition containing an epoxy resin, a curing agent, and a filler, in which a mixture of calcium carbonate and talc is used as the filler. is used, and the ratio of talc in the filler is set to 2 to 10% by weight.

In addition, Patent Document 2 discloses an adhesive composition containing an adhesive resin, core-shell polymer particles, and polymer particles. These improve adhesion performance by using two kinds of special core-shell polymer particles of several tens to hundreds of nano-size and polymer particles larger than the core-shell polymer particles.

JP-A-5-295340 WO2019/189238

However, it is difficult to say that any of these are sufficient. A main object of the present invention is to provide an adhesive composition that achieves both high adhesive strength and improved cohesive failure rate.

As a result of intensive studies by the present inventors to solve the above problems, a thermosetting resin [referred to as component (A)], thermoplastic resin particles [referred to as component (B)], a curing agent and / Alternatively, in an adhesive composition containing a curing accelerator [collectively referred to as component (C), the curing agent is referred to as component (C-1) and the curing accelerator is referred to as component (C-2)], the thermoplastic resin particles are It was found that when the tensile modulus of elasticity of the molded dumbbell test piece and the strain energy per unit volume are within the predetermined ranges, both high adhesive strength and improvement in cohesive failure rate are achieved. Based on such knowledge, the present invention was made through further intensive studies.

That is, the present invention provides an invention having the following configurations.
Section 1. thermosetting resin [referred to as component (A)],
thermoplastic resin particles [referred to as component (B)],
a curing agent and/or curing accelerator [collectively referred to as component (C), the curing agent being component (C-1) and the curing accelerator being component (C-2)];
An adhesive composition comprising
The component (B) complies with JIS K7161, and a No. 7 dumbbell test piece molded to have a width of 2 mm and a thickness of 1 mm has a tensile modulus of 1 GPa or less, and the stress-strain curve of the test piece. An adhesive composition comprising thermoplastic resin particles having a strain energy per unit volume of 20,000 kJ/m ³ or more.
Section 2. Item 2. The adhesive composition according to item 1, wherein component (A) is an epoxy resin.
Item 3. Item 3. The adhesive composition according to item 1 or 2, wherein the content of component (A) is 7 to 95% by mass with respect to the total amount of component (A), component (B) and component (C). .
Section 4. 4. The adhesive composition according to any one of items 1 to 3, wherein the component (B) has a volume average particle size of 2 to 30 μm.
Item 5. The adhesive composition according to any one of Items 1 to 4, which is used for bonding any of structural materials, composite materials, electrical/electronic materials, substrate materials, laminate materials, coating materials, and paints.
Item 6. A cured product of the adhesive composition according to any one of Items 1 to 5.
Item 7. A step of applying or pouring the adhesive composition according to any one of Items 1 to 5 onto the surface of an object to be adhered;
curing the adhesive composition;
A method of making an adhesive layer, comprising:
Item 8. A step of disposing the adhesive composition between the adhesive composition according to any one of Items 1 to 5 and a substrate and an adherend;
curing the adhesive composition;
A method of manufacturing an adhesive laminate, comprising:
Item 9. A step of injecting the adhesive composition according to any one of Items 1 to 5 between a substrate and an adherend;
curing the adhesive composition;
A method of manufacturing an adhesive layer body, comprising:

According to the present invention, it is possible to provide an adhesive composition that achieves both high adhesive strength and improved cohesive failure rate. The adhesive composition of the present invention is used for adhesive applications in various industrial fields, such as structural materials, composite materials, electrical/electronic materials, substrate materials, laminate materials, coating materials, and paints. can be suitably used for In particular, the adhesive composition of the present invention can be used to bond members made of metal materials such as iron, stainless steel and aluminum alloys and resin materials such as engineering plastics and carbon fiber reinforced plastics singly or in combination. It can be suitably used as an adhesive composition to be.

It is a graph showing the integrated value of the stress-strain curve.

The adhesive composition of the present invention will be described in detail below. As used herein, the term "comprising" includes "consisting essentially of" and "consisting of".

In addition, in this specification, a numerical value connected with "-" means a numerical range including the numerical values before and after "-" as lower and upper limits. If multiple lower limits and multiple upper limits are listed separately, any lower limit and upper limit can be selected and connected with "-".

<Component (A): Thermosetting resin>
The component (A) includes thermosetting resins such as epoxy resins, acrylic resins and silicone resins, and epoxy resins are preferred from the viewpoint of adhesiveness, insulating properties and mechanical properties. As these thermosetting resins, known resins used for epoxy resin-based adhesives, acrylic resin-based adhesives, silicone resin-based adhesives, and the like can be used. The component (A) resin contained in the adhesive composition of the present invention may be of one type or two or more types. Moreover, the component (A) may be liquid or solid, and is preferably liquid because it is easy to handle.

Any epoxy resin that has an epoxy group and can be cured may be used as the epoxy resin, and examples thereof include monoepoxy compounds and polyepoxy compounds.

Specific examples of monoepoxy compounds include butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-butylphenyl glycidyl ether, para-xylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexoate. , glycidyl benzoate, and the like.

Examples of polyepoxy compounds include bisphenol-type epoxy resins, epoxy resins obtained by glycidylating polyhydric phenol compounds, novolac-type epoxy resins, aliphatic ether-type epoxy resins, ether-ester-type epoxy resins, ester-type epoxy resins, Examples include amine-type epoxy resins and alicyclic epoxy resins.

Among polyepoxy compounds, specific examples of bisphenol type epoxy resins include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, Epoxy resins obtained by glycidylating bisphenols such as tetrabromobisphenol A, tetrachlorobisphenol A and tetrafluorobisphenol A can be mentioned.

Specific examples of epoxy resins obtained by glycidylating polyhydric phenol compounds include epoxy resins obtained by glycidylating dihydric phenol compounds such as biphenol, dihydroxynaphthalene, and 9,9-bis(4-hydroxyphenyl)fluorene, and 1 , 1,1-tris(4-hydroxyphenyl)methane and other trisphenol compounds, and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane and other tetrakisphenol compounds. An epoxy resin etc. are mentioned.

Specific examples of novolak-type epoxy resins include epoxy resins obtained by glycidylating novolac compounds such as phenol novolak type, cresol novolak type, bisphenol A novolak type, brominated phenol novolak type, and brominated bisphenol A novolak type.

Specific examples of aliphatic ether-type epoxy resins include epoxy resins obtained by glycidylating polyhydric alcohols such as glycerin and polyethylene glycol.

Specific examples of ether ester type epoxy resins include epoxy resins obtained by glycidylating hydroxycarboxylic acids such as paraoxybenzoic acid.

Specific examples of ester-type epoxy resins include epoxy resins obtained by glycidylating polycarboxylic acids such as phthalic acid and terephthalic acid.

Specific examples of amine-type epoxy resins include epoxy resins obtained by glycidylating amine compounds such as 4,4'-diaminodiphenylmethane and m-aminophenol.

Specific examples of alicyclic epoxy resins include 3,4-epoxycyclohexylmethyl-3′,4′-epoxycyclohexane carboxylate, 1,2-epoxy-4-vinylcyclohexane, bis(3,4-epoxycyclohexylmethyl ) adipate, limonene diepoxide, 3,4-epoxycyclohexylmethanol and the like.

Among these epoxy resins, polyepoxy compounds are preferred, bisphenol type epoxy resins and amine type epoxy resins are more preferred, and bisphenol A type epoxy resins and bisphenol F type epoxy resins are more preferably used.

In the adhesive composition of the present invention, the compounding amount of component (A) is preferably 7 to 95% by mass with respect to 100% by mass of the total amount of component (A), component (B), and component (C). %, more preferably 10 to 90 mass %, still more preferably 30 to 80 mass %.

<Component (B): Thermoplastic resin particles>
The adhesive composition of the present invention contains thermoplastic resin particles as component (B). Component (B) conforms to JIS K7161 and has a tensile modulus of 1 GPa or less for a No. 7 dumbbell test piece molded to have a width of 2 mm and a thickness of 1 mm. Furthermore, component (B) has a strain energy of 20000 kJ/m ³ or more per unit volume obtained from a stress-strain curve for the test piece.

The tensile modulus of the component (B) described above is calculated by the following method. First, the component (B) is formed into a film by pressing and molding with a hot press under the conditions of a temperature of 130 to 200 ° C., a pressure of 0.2 MPa, and 30 seconds, and a No. 7 dumbbell test with a width of 2 mm and a thickness of 1 mm. create a piece. The tensile modulus of the prepared dumbbell test piece is measured by a tensile test according to JIS K7161. More specifically, the tensile stress (σ) and tensile strain (ε) are measured by performing a tensile test under conditions of a distance between grips of 10 mm and a test speed of 0.5 mm/min to determine the tensile elastic modulus. The tensile modulus is calculated by a method conforming to JIS K7161, specifically, the gradient of a straight line (the following formula) at micro strain.
E=(σ ₂ −σ ₁ )/(ε ₂ −ε ₁ ) (Formula 1)
σ ₂ ; Tensile stress measured at "ε ₂ =0.0025" σ ₁ ; Tensile stress measured at "ε ₁ =0.0005"

When the tensile elastic modulus calculated by the above measurement is 1 GPa or less, the component (B) can relieve the stress generated at the interface between the adhesive layer and the base material when the adhesive composition is formed, so that the adhesive strength is increased. From the viewpoint of obtaining higher adhesive strength, it is preferably 0.7 GPa or less, more preferably 0.2 GPa or less. The lower limit of the tensile modulus is, for example, 0.01 GPa.

Also, the strain energy per unit volume of the component (B) is calculated by the following method. A stress-strain curve is obtained from the tensile test in which the tensile modulus is calculated, and the strain energy per unit volume is obtained. The strain energy per unit volume is the area enclosed from the starting point of the tensile test to the breaking point. calculate. As shown in FIG. 1, the integrated value is calculated by calculating the minimum rectangular area obtained by the minimum tensile stress within the strain width for each strain width of 0.0001 [mm / mm] from the start of tension. and total the area of all rectangles up to the breaking point.

The strain energy per unit volume obtained from the stress-strain curve calculated in the above measurement is 20000 kJ/m ³ or more, so that when the adhesive composition used is destroyed, the component (B) is applied to the adhesive layer. The effect of addition of N works sufficiently, and the fracture toughness is improved. From the viewpoint of further improving fracture toughness, the strain energy per unit volume of the test piece is preferably 30000 kJ/m ³ or more, more preferably 100000 kJ/m ³ or more. The upper limit of the strain energy is, for example, 2000000 kJ/m ³ .

The type of thermoplastic resin of component (B) is particles synthesized from a thermoplastic resin. For example, representative thermoplastic resins include polyolefin resins, nylon resins, polyester resins, polyvinyl alcohol resins, and thermoplastic polyurethane resins.

When the elastic modulus of the component (B) is lower than the elastic modulus of the cured product formed by the component (A) and the component (C), the stress generated during curing, particularly the strain at the interface between the adhesive layer and the adherend, is reduced. , the adhesive strength is excellent.

Examples of the polyolefin resins include polyolefin resins, copolymer resins of olefins and other monomers, and polystyrene resins.

Examples of the polyolefin resin include olefin homopolymers, copolymers, and acid-modified polymers thereof. Examples of olefin homopolymers include polyethylene and polypropylene. Examples of olefin copolymers include ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-octene copolymers and ethylene-1-hexene copolymers. Examples of acid-modified polymers of olefin homopolymers and copolymers include maleic anhydride-modified polyethylene and maleic anhydride-modified polypropylene.

Examples of the olefin that constitutes the copolymer resin of the olefin and other monomers include ethylene and propylene. Further, the other monomer is not particularly limited as long as it is a monomer copolymerizable with the olefin. Examples include vinyl ester, α,β-unsaturated carboxylic acid, α,β-unsaturated carboxylic anhydride, and , β-unsaturated carboxylic acid metal salts and α,β-unsaturated carboxylic acid esters. Examples of vinyl esters include vinyl acetate. Examples of the α,β-unsaturated carboxylic acid include (meth)acrylic acid. Here, (meth)acrylic acid means "methacrylic acid" and "acrylic acid". The same applies to (meth)acry below. Examples of α,β-unsaturated carboxylic acid anhydrides include maleic anhydride and the like, and examples of metal salts of α,β-unsaturated carboxylic acids include sodium salts and magnesium salts of (meth)acrylic acid. can be mentioned. Further, α,β-unsaturated carboxylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate and the like. These olefins and other monomers may be used alone or in combination of two or more.

Specific examples of copolymer resins of olefins and other monomers include ethylene/vinyl acetate copolymers, partially saponified ethylene/vinyl acetate copolymers, and ethylene/(meth)acrylic acid copolymers. coalescence, ethylene/maleic anhydride copolymer, propylene/maleic anhydride copolymer; ethylene/methyl methacrylate copolymer, partially saponified ethylene/methyl methacrylate copolymer, ethylene/ethyl methacrylate copolymer , partially saponified ethylene/ethyl methacrylate copolymer, ethylene/methyl acrylate copolymer, partially saponified ethylene/methyl acrylate copolymer, ethylene/ethyl acrylate copolymer, ethylene/ethyl acrylate Partially saponified copolymers, ethylene/(meth)acrylic acid ester copolymers such as ethylene/glycidyl (meth)acrylate copolymers and partially saponified products thereof; ethylene/glycidyl (meth)acrylate/methyl (meth)acrylate Ethylene/(meth)acrylate/(meth)acrylate copolymer such as copolymer; Ethylene/(meth)acrylate/vinyl acetate such as ethylene/glycidyl (meth)acrylate/vinyl acetate copolymer Copolymers, ethylene/(meth)acrylic acid ester/maleic anhydride copolymers such as ethylene/methyl (meth)acrylate/maleic anhydride copolymers, and resins of these metal salts can be mentioned. .

Examples of nylon-based resins include -[NH(CH ₂ ) ₅ CO]-, -[NH(CH ₂ ) ₄ NHCO(CH ₂ ) ₄ CO]-, -[NH(CH ₂ ) ₆ NHCO(CH ₂ ) ₄ CO]-, -[NH(CH ₂ ) ₆ NHCO(CH ₂ ) ₈ CO]-, -[NH(CH ₂ ) ₁₀ CO]- and -[NH(CH ₂ ) ₁₁ CO]- A nylon resin having at least one selected from among structural units can be mentioned. Specific examples thereof include nylon 6, nylon 46, nylon 66, nylon 610, nylon 11, nylon 12, copolymers thereof, and polyamide elastomers which are copolymers of polyesters and polyalkylene ether glycols. mentioned.

Polyester-based resins include, for example, acid components containing terephthalic acid and isophthalic acid, and diol components containing ethylene glycol, butylene glycol, diethylene glycol, polyethylene glycol, 1,4-butanediol and 1,6-hexanediol. A polyester resin obtained by a condensation reaction can be mentioned. Specific examples thereof include terephthalic acid/ethylene glycol copolymer polyester resin, terephthalic acid/butylene glycol copolymer polyester resin, terephthalic acid/isophthalic acid/1,4-butanediol copolymer polyester resin, terephthalic acid/isophthalic acid/ 1,6-hexanediol copolymer polyester resin, terephthalic acid/isophthalic acid/polyethylene glycol copolymer polyester resin, terephthalic acid/isophthalic acid/ethylene glycol/1,4-butanediol copolymer polyester resin, terephthalic acid/isophthalic acid/ Examples include adipic acid/1,4-butanediol copolymer polyester resin and terephthalic acid/isophthalic acid/1,4-butanediol/diethylene glycol copolymer polyester resin. Further, examples of the polyester-based resin include a polyester-based thermoplastic elastomer which is a copolymer of the above-described copolymerized polyester resin and polyalkylene ether glycol.

In the present invention, the polyolefin resin, nylon resin, polyester resin, polyvinyl alcohol resin, and thermoplastic polyurethane resin may be used alone or in combination of two or more.

Preferred component (B) among the above resins includes polyolefin-based resins, nylon copolymers, nylon elastomers, and thermoplastic resins from the viewpoint of having higher flexibility and higher plastic deformation ability than the component (A) curable resin. Polyurethane resins, more preferably polyethylene, ethylene/vinyl acetate copolymer, ethylene/(meth)acrylic acid copolymer, ethylene/(meth)acrylic acid ester copolymer, ethylene/glycidyl methacrylate copolymer Polymers and 12 nylon elastomers can be mentioned.

The volume average particle size of component (B) is, for example, 1 μm to 100 μm, preferably 2 μm to 30 μm. If it is smaller than 1 μm, it is difficult to handle, and the viscosity increases in the step of mixing with the component (A), which may impair workability. If the particle size is larger than 100 μm, the particles tend to separate when mixed with the component (A), which may result in poor dispersion stability. When the thickness is from 2 μm to 30 μm, the effect of addition can be sufficiently exerted without impairing the workability.

The volume average particle size of component (B) is the volume average particle size determined by the electrical detection zone method (pore electrical resistance method).

A specific device for measuring the volume average particle size by the pore electrical resistance method is, for example, an electrical detection type particle size distribution measuring device (manufactured by Beckman Coulter under the trade name "Coulter Multisizer"). There are various sizes of aperture diameters used for measurement, and each aperture diameter has a measurement range (size of volume average particle diameter) suitable for measurement. The aperture diameter can be selected so as to cover the particle diameters of the particles to be measured. When measuring particles having a particle size smaller than the measurement range for which an aperture diameter of 100 μm is suitable, an aperture size smaller than 100 μm can be selected, and particles having a particle size larger than the measurement range for which an aperture diameter of 100 μm is suitable can be measured. Sometimes aperture diameters larger than 100 μm can be chosen.

The shape of the component (B) according to the present invention is not particularly limited as long as workability is not impaired, and is preferably solid, particularly particulate, and its shape includes spherical, irregular, and scaly. A spherical shape is preferable from the viewpoint of easy dispersion in the adhesive composition and suppression of increase in viscosity.

Inorganic pigments such as alumina and silica, metal powders such as iron, copper, nickel and cobalt, and organic pigments such as ultraviolet absorbers and heat stabilizers are contained in or on the surface of the component (B) thermoplastic resin particles used in the present invention. Substances can also be included.

In the adhesive composition of the present invention, the amount of component (B) is preferably 5 to 50% by mass with respect to 100% by mass of the total amount of component (A), component (B) and component (C). and more preferably 10 to 40% by mass.

<Component (C): Curing Agent (C-1) and/or Curing Accelerator (C-2)>
The curing agent as component (C-1) is one that reacts with component (A) to give a cured product. Component (C-1) may be used alone or in combination of two or more. When two or more components (C-1) are mixed and used, the mixture of the mixed curing agents is regarded as one component (C-1).

Examples of component (C-1) include amine-based curing agents, amide-based curing agents, acid anhydride-based curing agents, phenol-based curing agents, mercaptan-based curing agents, isocyanate-based curing agents, active ester-based curing agents, and cyanate. Examples include ester-based curing agents.

Examples of amine-based curing agents include chain aliphatic amines such as ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; isophoronediamine, bis(4-aminocyclohexyl)methane, bis(aminomethyl)cyclohexane, alicyclic amines; aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, diethyltoluenediamine, and diethyldiaminodiphenylmethane;

Examples of amide-based curing agents include dicyandiamide and its derivatives, and polyamide resins (polyaminoamide, etc.).

Examples of acid anhydride curing agents include aliphatic acid anhydrides such as maleic anhydride and dodecenyl succinic anhydride; aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride and pyromellitic anhydride; methyl anhydride alicyclic acid anhydrides such as nadic acid, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and 4-methylhexahydrophthalic anhydride;

Examples of phenol-based curing agents include phenol novolak resin, cresol novolak resin, biphenyl novolak resin, triphenylmethane phenol resin, naphthol novolak resin, phenol biphenylene resin, phenol aralkyl resin, biphenyl aralkyl phenol resin, and modified polyphenylene ether. Examples thereof include resins and compounds having a benzoxazine ring.

Mercaptan-based curing agents include, for example, trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate) , tetraethylene glycol bis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis (3-mercaptobutyryloxy) butane, trimethylolpropane tris (3-mercaptobutyrate ), trimethylolethane tris(3-mercaptobutyrate), polysulfide polymer and the like.

Examples of isocyanate-based curing agents include hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, lysine diisocyanate, isophorone diisocyanate and norbornane diisocyanate.

Active ester curing agents are compounds having one or more ester groups that react with component (A) in one molecule, and include phenyl esters, naphthyl esters, thiophenyl esters, N-hydroxyamine esters, and heterocyclic hydroxy compound esters. etc.

Examples of cyanate ester curing agents include bisphenol type cyanate resins such as novolac type cyanate resins, bisphenol A type cyanate resins, bisphenol E type cyanate resins, and tetramethylbisphenol F type cyanate resins.

In the adhesive composition of the present invention, the component (C-1) is at least one selected from the group consisting of amine-based curing agents, acid anhydride-based curing agents, amide-based curing agents, and phenol-based curing agents. is preferably used, and an amine-based curing agent and an acid anhydride-based curing agent are more preferable.

In the adhesive composition of the present invention, the amount of component (C-1) to be blended is the amount of component (C-1) per equivalent of the reactive functional group (eg, epoxy group) in component (A), which is a thermosetting resin. ), it is preferable to adjust the amount to be 0.1 to 5 equivalents of the reactive functional group. The equivalent weight of the reactive functional group in component (C-1) is more preferably 0.3 to 3 equivalents, still more preferably 0.5 to 2 equivalents.

The curing accelerator as component (C-2) is a component that accelerates the curing of component (A), which is a thermosetting resin. In addition, by using both the component (C-2) and the component (C-1), the curing reaction rate can be increased and the strength of the resulting cured product can be increased. Component (C-2) may be used alone or in combination of two or more. When two or more types of components (C-2) are mixed and used, the mixture of the mixed curing accelerators is regarded as one component (C-2).

Examples of component (C-2) include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1,2-dimethylimidazole, 1-benzyl-2- imidazole compounds such as methylimidazole; secondary amines such as piperidine; DBU (1,8-diazabicyclo(5,4,0)-undecene-7), DBN (1,5-diazabicyclo(4,3,0)- nonene-5), tertiary amines such as 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, triethylenediamine, 2-(dimethylaminomethyl)phenol, 4-dimethylaminopyridine; triphenylphosphine , phosphorus-based compounds such as tetraphenylphosphonium tetraphenylborate, Lewis acid compounds, cationic polymerization initiators, and the like.

In the adhesive composition of the present invention, as the component (C-2), it is preferable to use at least one selected from the group consisting of imidazole compounds, tertiary amines, phosphorus compounds, and cationic polymerization initiators. .

In the adhesive composition of the present invention, the amount of component (C-2) is preferably 0.01 to 10 parts by mass per 100 parts by mass of component (A). It is more preferably 0.1 to 5 parts by mass, still more preferably 0.5 to 5 parts by mass.

In the adhesive composition of the present invention, the total content of component (A), component (B), and component (C) is preferably 10% by mass or more, more preferably 30% by mass or more, and still more preferably 50% by mass. % or more, more preferably 70 mass % or more, and may be 100 mass %.

<Additives that can be included in the adhesive composition>
The adhesive composition of the present invention may contain other additives, if necessary, as long as the objects and effects of the present invention are not impaired.

Additives include, for example, organic fillers not included in component (B), thermoplastic resins, rubbers, elastomers, composite particles, inorganic fillers, conductive particles, carbon black, antioxidants, inorganic phosphors, and lubricants. , UV absorber, heat and light stabilizer, antistatic agent, polymerization inhibitor, antifoaming agent, solvent, anti-aging agent, radical inhibitor, adhesion improver, flame retardant, surfactant, storage stability improver, Ozone anti-aging agents, thickeners, plasticizers, radiation shielding agents, nucleating agents, coupling agents, conductivity imparting agents, phosphorus-based peroxide decomposers, pigments, metal deactivators, physical property modifiers, etc. be done.

The content of the additive with respect to the entire adhesive composition is 90% by mass or less.

<Method for producing adhesive composition>
The adhesive composition of the present invention can be produced by mixing component (A), component (B), component (C), and, if necessary, other additives.

The mixing method is not particularly limited as long as it is a method that allows each component to be uniformly mixed.

Since the adhesive composition of the present invention has a low viscosity, it can be prepared without adding a solvent. , acetone, cyclohexanone, methylcyclohexane, cyclohexane, etc.) may be added.

A cured product can be obtained by curing the adhesive composition of the present invention. The curing method depends on the type of curable resin, but can be carried out, for example, by heating the composition. In the case of curing by heating, the curing temperature is usually room temperature (25° C.) to 250° C., and the curing time can usually be set within the range of 30 seconds to 1 week. Considering the influence of the component (B) of the present invention on the thermal properties and interaction with other components, and from the viewpoint of preventing deterioration due to heat history, the curing temperature is 40 ° C. to 200 ° C., and the curing time is is preferably set between 1 minute and 12 hours.

The adhesive composition of the present invention can be suitably used as an adhesive for structural materials, composite materials, electric/electronic materials, substrate materials, and laminate materials, and by being mixed in coating materials, paints, and the like. . Adhesives for structural materials include, for example, adhesives for bonding metal materials, polymer materials, inorganic materials, etc. used in automobiles, vehicles (bullet trains, trains), aircraft, the space industry, and the like. Examples of adhesives for electrical/electronic materials, substrate materials, and laminate materials include adhesives for interlayers of multilayer substrates, semiconductors, and mounting, sealants, and underfills.

<Cured Product of Adhesive Composition>
The cured product of the adhesive composition of the present invention is obtained by curing the above-described adhesive composition of the present invention. A method for curing the adhesive composition of the present invention is not particularly limited, but as described above, a method of heating the adhesive composition of the present invention can be used.

<Method for producing adhesive layer>
The adhesive layer of the present invention can be produced by a production method comprising the steps of applying or pouring the adhesive composition of the present invention onto the surface of an object to be adhered, and curing the adhesive composition. . The method for curing the adhesive composition of the present invention is as described above.

<Method for manufacturing adhesive laminate>
An adhesive laminate is obtained through a step of disposing the adhesive composition of the present invention between a substrate and an adherend, and a step of curing the adhesive composition. The method for curing the adhesive composition of the present invention is as described above.

The present invention will be described in detail below with examples and comparative examples. However, the present invention is not limited to the examples.

<Component (A): Thermosetting resin>
The following thermosetting resins (A-1) and (A-2) were used as component (A).
[Thermosetting resin A-1]
A bisphenol F type epoxy resin (jER806: epoxy equivalent 167 manufactured by Mitsubishi Chemical Corporation) was used as component (A-1).
[Thermosetting resin A-2]
A bisphenol A type epoxy resin (jER828: epoxy equivalent 186 manufactured by Mitsubishi Chemical Corporation) was used as component (A-2).

<Component (B): Thermoplastic resin particles>
The following thermoplastic resin particles (B-1) to (B-7) were used as the component (B).

[Thermoplastic resin particles (B-1)]
Low-density polyethylene (volume average particle size: 10 μm, melting point: 106° C., Flowbeads CL2080 manufactured by Sumitomo Seika Co., Ltd.) was used as thermoplastic resin particles (B-1). The particles are formed into a film by a heat press machine (machine name: manual hydraulic vacuum heating press manufactured by Imoto Seisakusho Co., Ltd.) under the conditions of a temperature of 130 ° C. and a pressure of 0.2 MPa for 30 seconds, and a punching machine (machine name: SD type lever type A dumbbell No. 7 test piece was prepared with a sample cutter SDL-100 (manufactured by Dumbbell Co.). The prepared test piece was subjected to a tensile test using a tensile tester (AGS-X, manufactured by Shimadzu Corporation) under the conditions of a distance between grips of 10 mm and a test speed of 0.5 mm / min, and a stress-strain curve was obtained. Created. The tensile elastic modulus determined by a method conforming to JIS K7161 was 0.2 GPa. The strain energy per unit volume obtained from the stress-strain curve was 76204 kJ/m ³ .

[Thermoplastic resin particles (B-2)]
High-density polyethylene (volume average particle size: 10 μm, melting point: 130° C., Flowbeads HE3040 manufactured by Sumitomo Seika Co., Ltd.) was used as thermoplastic resin particles (B-2). The tensile modulus and strain energy per unit volume were measured in the same manner as for the thermoplastic resin particles (B-1), except that the temperature of the hot press was changed to 160°C. As a result of the measurement, the tensile modulus was 1 GPa and the strain energy per unit volume was 30702 kJ/m ³ .

[Thermoplastic resin particles (B-3)]
160 g of ethylene/methyl methacrylate copolymer resin (MMA content: 10% mass part), 224 g of deionized water, and ethylene oxide/propylene as an emulsifier were placed in a 1-liter pressure-resistant autoclave equipped with a turbine-type stirring blade of 50 mm in diameter. 16 g of an oxide copolymer (weight average molecular weight: 15,500, ethylene oxide content: 80% by mass) was introduced and sealed. Next, the temperature inside the autoclave was raised to 150° C. while stirring at 500 rpm. After stirring for an additional 30 minutes while maintaining the internal temperature at 150°C, the content was cooled to 25°C to obtain an aqueous dispersion of ethylene/methyl methacrylate copolymer. The aqueous dispersion is filtered through filter paper, washed with water, and dried at 60° C. for 24 hours in a vacuum dryer to obtain ethylene/methyl methacrylate copolymer particles, which are used as thermoplastic resin particles (B-3). and The thermoplastic resin particles (B-3) thus obtained had a volume average particle diameter of 13 μm and a melting point of 100°C. The tensile modulus and strain energy per unit volume were measured in the same manner as for the thermoplastic resin particles (B-1). As a result of measurement, the elastic modulus was 0.1 GPa and the strain energy per unit volume was 591702 kJ/m ³ .

[Thermoplastic resin particles (B-4)]
An ethylene/acrylic acid copolymer (AA content 7% by mass, volume average particle size 10 μm, melting point 97° C., Flowbeads EA209 manufactured by Sumitomo Seika Co., Ltd.) was used as thermoplastic resin particles (B-4).
The tensile modulus and strain energy per unit volume were measured in the same manner as for the thermoplastic resin particles (B-1). As a result of measurement, the elastic modulus was 0.1 GPa and the strain energy per unit volume was 572789 kJ/m ³ .

[Thermoplastic resin particles (B-5)]
160 g of ethylene/glycidyl methacrylate copolymer resin (GMA content: 19% by mass), 224 g of deionized water, and ethylene oxide/propylene oxide as an emulsifier were placed in a pressure-resistant autoclave having an internal volume of 1 liter equipped with a turbine-type stirring blade with a diameter of 50 mm. 16 g of a polymer (weight-average molecular weight: 15,500, ethylene oxide content: 80% by mass) was introduced and sealed. Next, the temperature inside the autoclave was raised to 150° C. while stirring at 500 rpm. After stirring for an additional 30 minutes while maintaining the internal temperature at 150°C, the content was cooled to 25°C to obtain an aqueous dispersion of an ethylene/glycidyl methacrylate copolymer. Next, the aqueous dispersion is filtered through filter paper, washed with water, and dried in a vacuum dryer at 40° C. for 24 hours to obtain ethylene/glycidyl methacrylate copolymer particles, which are thermoplastic resin particles (B- 5). The resulting thermoplastic resin particles (B-5) had a volume average particle diameter of 13 μm and a melting point of 88°C. The tensile modulus and strain energy per unit volume were measured in the same manner as for the thermoplastic resin particles (B-1). As a result of measurement, the elastic modulus was 0.1 GPa and the strain energy per unit volume was 23037 kJ/m ³ .

[Thermoplastic resin particles (B-6)]
12 nylon (volume average particle diameter 20 μm, melting point 175° C., Orgasol 2002D manufactured by Arkema) was used as thermoplastic resin particles (B-6).
The tensile modulus and strain energy per unit volume were measured in the same manner as for the thermoplastic resin particles (B-1), except that the temperature of the hot press was changed to 200°C. As a result of measurement, the elastic modulus was 1.2 GPa and the strain energy per unit volume was 125055 kJ/m ³ .

[Thermoplastic resin particles (B-7)]
Polymethyl methacrylate (volume average particle diameter 10 μm, microspheres manufactured by Matsumoto Yushi Co., Ltd.) was used as thermoplastic resin particles (B-7).
The tensile modulus and strain energy per unit volume were measured in the same manner as for the thermoplastic resin particles (B-1), except that the temperature of the hot press was changed to 200°C. As a result of measurement, the elastic modulus was 2.6 GPa and the strain energy per unit volume was 8661 kJ/m ³ .

<Component (C-1): Curing agent>
As component (C-1), the following curing agents (C-1a) and (C-1b) were used, respectively.
[Curing agent (C-1a)]
An acid anhydride-based curing agent (Rikacid MH700; a liquid alicyclic acid anhydride containing 4-methylhexahydrophthalic anhydride as a main component, manufactured by Shin Nippon Rika Co., Ltd.) was used as a curing agent (C-1a).
[Curing agent (C-1b)]
An amine-based curing agent (Kayahard AA; diethyldiaminodiphenylmethane, manufactured by Nippon Kayaku Co., Ltd.) was used as the curing agent (C-1b).

<Component (C-2): Curing accelerator>
As components (C-2), the following curing accelerator (C-2a) and curing accelerator (C-2b) were used, respectively.
[Curing accelerator (C-2a)]
An imidazole-based curing accelerator (Curesol 1B2MZ; 1-benzyl-2-methylimidazole, manufactured by Shikoku Kasei Co., Ltd.) was used as the curing accelerator (C-2a).
[Curing accelerator (C-2b)]
An imidazole-based curing accelerator (Curesol 2E4MZ; 2-ethyl-4-methylimidazole, manufactured by Shikoku Kasei Co., Ltd.) was used as the curing accelerator (C-2b).

<Preparation of each composition>
[Example 1: Adhesive composition (1)]
In the following procedure, component (A-1) 38.7 parts by mass (functional group equivalent: 0.23), component (B-1) 23 parts by mass, component (C -1a) 37.7 parts by mass and component (C-2a) 0.6 parts by mass were weighed into a plastic container, and at room temperature using Awatori Rentaro (ARE-310, manufactured by Thinky Co., Ltd.) The mixture was stirred at 2000 rpm for 1 minute and defoamed at 2200 rpm for 1 minute to prepare an adhesive composition (1).

(Examples 2-8, Comparative Examples 1-7: Adhesive compositions (2)-(15))
Component (A), component (B), and component (C) were weighed into a plastic container so as to have the composition shown in Table 1, respectively, and Awatori Rentaro (ARE-310, manufactured by Thinky Co., Ltd.) ) at 2000 rpm for 1 minute and defoamed at 2200 rpm for 1 minute to prepare adhesive compositions (2) to (15).

<Evaluation of adhesive strength and cohesive failure rate>
(1) Tensile shear bond strength and cohesive failure rate for aluminum plate Adhesive compositions (1) to (15) were each pretreated so that the bond part was a rectangle of 12.5 mm × 25 mm (JIS H4000 A1050P size 3 mm × 25 mm × 100 mm), bonded to another aluminum plate, heated at a temperature of 60 ° C. for 60 minutes, heated to 100 ° C. at 2 ° C./min, and heated to 100 ° C. at 100 ° C. Then, the temperature was raised to 150° C. at a rate of 2.5° C./min, and the mixture was cured by continuously heating at 150° C. for 120 minutes to obtain a tensile shear adhesion test piece. Here, the pretreatment means a treatment method in which the substrate is immersed in an organic solvent and an alkaline bath at 70° C. in addition to sandblasting.
The resulting tensile shear adhesion test piece was subjected to a tensile shear adhesion test using a tensile tester (AGS-X, manufactured by Shimadzu Corporation) under the conditions of a distance between grips of 100 mm and a test speed of 2 mm/min. . The tensile shear adhesive strength (MPa) to the aluminum plate was calculated from the measured value (N) of the maximum breaking strength after the test and the area (mm ² ) of the adhesive portion. Furthermore, the fracture surface of the test piece after the tensile shear adhesion test was visually observed, and the ratio of the area of the cured adhesive composition remaining on the aluminum plate surface of the fracture surface to the area of the entire bonded portion was calculated. Table 1 shows the results.

Claims (9)

a thermosetting resin [referred to as component (A)],
thermoplastic resin particles [referred to as component (B)],
and,
a curing agent and/or curing accelerator [collectively referred to as component (C), the curing agent being component (C-1) and the curing accelerator being component (C-2)];
An adhesive composition comprising
The component (B) complies with JIS K7161, and a No. 7 dumbbell test piece molded to have a width of 2 mm and a thickness of 1 mm has a tensile modulus of 1 GPa or less, and the stress-strain curve of the test piece. An adhesive composition comprising thermoplastic resin particles having a strain energy per unit volume of 20,000 kJ/m ³ or more. The adhesive composition according to claim 1, wherein component (A) is an epoxy resin. The adhesive according to claim 1 or 2, wherein the content of component (A) is 7 to 95% by mass with respect to the total amount of component (A), component (B), and component (C). Composition. The adhesive composition according to claim 1 or 2, wherein the component (B) has a volume average particle size of 2 to 30 µm. The adhesive composition according to claim 1 or 2, which is used for bonding any of structural materials, composite materials, electric/electronic materials, substrate materials, laminate materials, coating materials, and paints. A cured product of the adhesive composition according to claim 1 or 2. A step of applying or pouring the adhesive composition according to claim 1 or 2 onto the surface of an object to be adhered;
curing the adhesive composition;
A method of making an adhesive layer, comprising: A step of disposing the adhesive composition according to claim 1 or 2 between a substrate and an adherend;
curing the adhesive composition;
A method of manufacturing an adhesive laminate, comprising: A step of injecting the adhesive composition according to claim 1 or 2 between a substrate and an adherend;
curing the adhesive composition;
A method of manufacturing an adhesive laminate, comprising:

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