An epoxy resin modifier, an epoxy resin composition containing the same, an adhesive comprising the epoxy resin composition, and a resin cured product formed by curing the epoxy resin composition.

Abstract

[Problem] An epoxy resin modifier capable of imparting excellent fracture toughness and peel adhesion while maintaining high transparency when formulated into an epoxy resin and cured, an epoxy resin composition containing the same, an adhesive and underfill material made of the epoxy resin composition, and a cured product made by curing the epoxy resin composition are provided. [Solution] The epoxy resin modifier of the present invention comprises an ABA-type triblock copolymer having an A block having a structural unit (a-1) represented by general formula (1) and a structural unit (a-2) derived from a (meth)acrylate having a chain alkyl group, and a B block having a structural unit (b) derived from a (meth)acrylate having a chain alkyl group or a cyclic alkyl group, wherein the content of the structural unit (a-1) is 85 mass% or more and less than 100 mass% in each A block 100 mass%, and the content of the structural unit (a-2) is greater than 0 mass% and less than 15 mass% in each A block 100 mass%. [In general formula (1), R1 is a hydrogen atom or a methyl group. 0≤n≤10, Q is a cyclic ether group or a cyclic thioether group of 4 to 6 members.]

Description

Technology Field

[0001] The present invention relates to an epoxy resin modifier, an epoxy resin composition containing the same, an adhesive and underfill material comprising the epoxy resin composition, and a resin cured product comprising the epoxy resin composition. Background Technology

[0002] Epoxy resin is a general term for thermosetting resins obtained by mixing an epoxy resin having epoxy groups (main component) with amines, acid anhydrides, etc. (curing agents) and performing a heat curing treatment. Because epoxy resins possess excellent tensile strength, solvent resistance, and electrical properties in addition to having a high modulus of elasticity, they are used in structural adhesives for automobiles, paints for construction and civil engineering, encapsulating materials (potting materials, underfill materials) for electronic materials such as semiconductors, composite materials for aircraft, and composite materials for sports equipment. For example, when a semiconductor circuit is subjected to a heat cycle test, excessive mechanical stress is applied to solder bumps, etc., due to the difference in the coefficient of linear expansion between the circuit board and the semiconductor chip. This can cause cracks in the solder bumps, etc., and impair the connection reliability of the semiconductor circuit. To solve this problem, an underfill material made of epoxy resin is filled into the gap between the circuit board and the semiconductor chip.

[0003] However, because epoxy resin has a high modulus of elasticity, it also has the characteristic that minute cracks in the resin tend to propagate easily. For this reason, fracture toughness and peel adhesion are weak, and improvements are required.

[0004] Accordingly, numerous attempts are being made to improve the toughness or peel adhesion of epoxy resins.

[0005] For example, Patent Document 1 discloses that toughness is improved by incorporating a block copolymer having a structural unit derived from (meth)acrylate having a cyclic ether group or a cyclic thioether group having a 4- to 6-membered ring in an epoxy resin, and a structural unit derived from (meth)acrylate having a chain alkyl group or a cyclic alkyl group having a block copolymer having a block copolymer having a structural unit derived from (meth)acrylate having a chain alkyl group or a cyclic alkyl group.

[0006] Patent Document 2 discloses that toughness (impact resistance) is improved by incorporating core / shell particles, in which the main component of the core is polybutadiene or polybutyl acrylate and the main component of the shell is an acrylate or methacrylate-based polymer, into an epoxy resin.

[0007] Patent document 3 discloses that toughness and stiffness are improved by incorporating a block copolymer into an epoxy resin, the block copolymer being composed of a polymer block (a) made of a (meth)acrylic polymer and a polymer block (b) made of an acrylic polymer different from the polymer block (a).

[0008] Patent document 4 discloses that fracture toughness and peel adhesion strength are improved by incorporating a block copolymer having one or more polymer blocks A, which are mainly composed of structural units derived from alkyl methacrylates, and one or more polymer blocks B, which are mainly composed of structural units derived from alkyl acrylates, into an epoxy resin. Prior art literature

[0009] Japanese Patent Publication No. 2018-35266, Japanese Patent Publication No. Hei 9-25393, Japanese Patent Republished No. 2014-142024, Japanese Patent Republished No. 2009-101961 The problem to be solved

[0010] Recently, there has been a trend toward higher performance in automotive structural adhesives, electronic materials such as semiconductors, and aerospace materials. Consequently, higher performance is required for the epoxy resins used in these applications. However, to achieve sufficient improvements in toughness or peel adhesion using the aforementioned methods, it is necessary to increase the content ratio of the modifier (block copolymer or core / shell particles) within the epoxy resin. Conversely, epoxy resins with a high proportion of the modifier suffer from weakened inherent characteristics, such as tensile strength and solvent resistance, making them unsuitable for applications requiring such properties. Furthermore, since the resin loses its transparency, it cannot be applied to materials requiring transparency.

[0011] The present invention aims to provide an epoxy resin modifier capable of imparting excellent fracture toughness and peel adhesion while maintaining high transparency when combined with an epoxy resin to form a cured product, an epoxy resin composition containing the same, an adhesive made of the epoxy resin composition, an underfill material made of the epoxy resin, and a cured product made by curing the epoxy resin composition. means of solving the problem

[0012] The epoxy resin modifier of the present invention capable of solving the above problem comprises a block copolymer, wherein the block copolymer is an ABA-type triblock copolymer having a block A having a structural unit (a-1) represented by the following general formula (1) and a structural unit (a-2) derived from a (meth)acrylate having a chain-like alkyl group, and a block B having a structural unit (b) derived from at least one vinyl monomer selected from the group consisting of a (meth)acrylate having a chain-like alkyl group and a (meth)acrylate having a cyclic alkyl group, wherein the content of the structural unit (a-1) represented by the general formula (1) in each block A is 85 mass% or more and less than 100 mass% in 100 mass% of block A, and the content of the structural unit (a-2) derived from the (meth)acrylate having a chain-like alkyl group is greater than 0 mass% in 100 mass% of block A. It is characterized by being 15 mass% or less.

[0013]

[0014] [In general formula (1), R 1 It is a hydrogen atom or a methyl group. 0≤n≤10, Q is a cyclic ether group of 4 to 6 members or a cyclic thioether group.]

[0015] The block copolymer included in the epoxy resin modifier of the present invention is an ABA-type triblock copolymer having an A block, which is a region with high compatibility with the epoxy resin, and a B block, which is a region with low compatibility with the epoxy resin.

[0016] The above-mentioned solid-state A block contains a structural unit (a-1) with high affinity for epoxy resin and a structural unit (a-2) with lower affinity for epoxy resin compared to the structural unit (a-1). It is believed that by setting the content of the structural unit (a-1) with high affinity for epoxy resin to 85 mass% or more and less than 100 mass% in each A block 100 mass%, and the content of the structural unit (a-2) with low affinity for epoxy resin to 0 mass% or more and 15 mass% or less in each A block 100 mass%, the affinity of the A block to the epoxy resin becomes appropriate, neither too high nor too low.

[0017] It is thought that block B has lower affinity with epoxy resin and lower compatibility with epoxy resin compared to block A because it does not substantially contain structural unit (a-1).

[0018] When the epoxy resin modifier of the present invention is incorporated into an epoxy resin, a state in which the low-compatibility B block is dispersed without being compatible with the epoxy resin, i.e., an island structure, is formed. It is believed that during crack extension of the epoxy resin, this island portion causes cavitation, and by utilizing the generated voids to allow the surrounding resin to perform stress relief, the energy of the crack extension can be dispersed. The degree to which the energy of the crack extension can be dispersed is influenced by the size and shape of the island portion.

[0019] When the epoxy resin modifier of the present invention is incorporated into an epoxy resin, the island portions formed by the B blocks become a more uniform nano-sized string-shaped dispersion state capable of efficiently dispersing the crack extension energy in the epoxy resin; therefore, the cured product of the resulting epoxy resin composition maintains high transparency while improving fracture toughness and peel adhesion.

[0020] The present invention comprises an epoxy resin, a curing agent, and an epoxy resin composition containing said epoxy resin modifier. Furthermore, the present invention comprises an adhesive made of said epoxy resin composition, an underfill material made of said epoxy resin composition, and a resin cured product made by curing said epoxy resin composition. Effects of the invention

[0021] According to the present invention, an epoxy resin modifier can be provided that, when formulated into an epoxy resin to form a cured product, maintains high transparency while imparting excellent fracture toughness and peel adhesion. The cured product of the epoxy resin composition of the present invention has high transparency and excellent fracture toughness and peel adhesion. Brief explanation of the drawing

[0022] Figure 1 is a photograph serving as a drawing showing the phase separation state of the cured product of epoxy resin composition No. 2. Figure 2 is a photograph serving as a drawing showing the phase separation state of the cured product of epoxy resin composition No. 10. Figure 3 is a photograph serving as a drawing showing the phase separation state of the cured product of epoxy resin composition No. 6. Specific details for implementing the invention

[0023] The present invention will be described below based on preferred embodiments, but the present invention is not limited to the following embodiments.

[0024] The epoxy resin modifier of the present invention contains a block copolymer.

[0025] Block copolymer

[0026] The block copolymer containing the epoxy resin modifier of the present invention is an ABA-type triblock copolymer having a block A having a structural unit (a-1) represented by the general formula (1) described below and a structural unit (a-2) derived from a (meth)acrylate having a chain alkyl group, and a block B having a structural unit (b) derived from at least one vinyl monomer selected from the group consisting of a (meth)acrylate having a chain alkyl group and a (meth)acrylate having a cyclic alkyl group. In each block A, the content of the structural unit (a-1) represented by the general formula (1) is 85 mass% or more and less than 100 mass% in 100 mass% of block A, and the content of the structural unit (a-2) derived from the (meth)acrylate having a chain alkyl group is greater than 0 mass% and less than 15 mass% in 100 mass% of block A.

[0027] The above copolymer is preferably a (meth)acrylate-based copolymer. A (meth)acrylate-based copolymer is a copolymer having structural units derived from (meth)acrylate as a main component (50 mass% or more), and may contain structural units derived from vinyl monomers other than (meth)acrylate. The content of structural units derived from (meth)acrylate in the above copolymer is preferably 80 mass% or more and more preferably 90 mass% or more of the total 100 mass% of the copolymer.

[0028] In the present invention, “A block” can be replaced with “A segment”, and “B block” can be replaced with “B segment”. In the present invention, “vinyl monomer” refers to a monomer having a radically polymerizable carbon-carbon double bond in the molecule. “Structural unit derived from vinyl monomer” refers to a structural unit in which the radically polymerizable carbon-carbon double bond of the vinyl monomer polymerizes to become a carbon-carbon single bond. “(Meta)acrylate” refers to “at least one of acrylate and methacrylate”, and “(Meta)acrylate” refers to “at least one of acrylate and methacrylate”. Furthermore, a (meth)acrylate having a chain-like alkyl group is a (meth)acrylate having an acyclic alkyl group. In the present invention, “(meth)acrylate having a chain alkyl group” can be replaced with “(meth)acrylic acid chain alkyl ester” or “(meth)acrylic acid chain alkyl”, and “(meth)acrylate having a cyclic alkyl group” can be replaced with “(meth)acrylic acid cyclic alkyl ester” or “(meth)acrylic acid cyclic alkyl”.

[0029] Various constituent components of the above-mentioned block copolymer are described below.

[0030] (Block A)

[0031] Block A is a polymer block having a structural unit (a-1) represented by the following general formula (1) and a structural unit (a-2) derived from a (meth)acrylate having a chain-like alkyl group.

[0032]

[0033] [In Equation (1), R 1 It is a hydrogen atom or a methyl group. 0≤n≤10, Q is a cyclic ether group of 4 to 6 members or a cyclic thioether group.]

[0034] n in Equation (1) is preferably an integer from 0 to 10, more preferably an integer from 0 to 5, and even more preferably an integer from 0 to 3.

[0035] A cyclic ether or cyclic thioether group of a 4- to 6-membered ring, denoted by Q, is a group having a structure in which at least one of the carbon atoms constituting the ring of a 4- to 6-membered hydrocarbon is substituted with an oxygen atom or a sulfur atom. As long as the group has a structure in which at least one of the carbon atoms constituting the ring of a 4- to 6-membered hydrocarbon is substituted with an oxygen atom or a sulfur atom, the carbon atoms constituting the ring may be substituted with other atoms. Specific examples of other atoms include nitrogen atoms. In addition, two or more carbon atoms constituting the ring of a 4- to 6-membered hydrocarbon may be substituted with atoms other than carbon atoms. Furthermore, the bonds constituting the 4- to 6-membered ring may be saturated bonds or unsaturated bonds. In addition, the cyclic ether or cyclic thioether group of a 4- to 6-membered ring represented by Q may be substituted with a hydrogen atom directly bonded to an atom constituting the ring as a substituent. Examples of such substituents include hydrocarbon groups. Furthermore, the group represented by Q is not a cyclic acid anhydride group that opens easily, as it is considered to have a cyclic ether or cyclic thioether structure and high compatibility with epoxy resins.

[0036] Specific examples of cyclic ether groups of 4 to 6 members denoted by Q include, for example, cyclic ether groups in which a carbon atom constituting a 4 to 6-membered ring is substituted with at least one oxygen atom, such as an oxetaneyl group (4), a furanyl group (furyl group, 5), a tetrahydrofurfuryl group (6), a pyranyl group (7a, 7b), a dihydropyranyl group (8a, 8b), a tetrahydropyranyl group (9), a dioxolanyyl group (10), and a dioxaneyl group (11); and cyclic ether groups in which a carbon atom constituting a 4 to 6-membered ring is substituted with an oxygen atom and a nitrogen atom, such as an oxazole group (12), an oxazineyl group (13a~13h), and a morpholino group (14). Examples of cyclic thioether groups in which carbon atoms constituting the 4- to 6-membered ring are substituted with sulfur atoms include thiethanolyl groups (15) and thienyl groups (16); cyclic thioether groups in which carbon atoms constituting the 4- to 6-membered ring are substituted with sulfur atoms and nitrogen atoms include thiazole groups (17); and cyclic ether groups (or cyclic thioether groups) in which carbon atoms constituting the 4- to 6-membered ring are substituted with oxygen atoms and sulfur atoms include oxathiolanyl groups (18). The chemical formulas of the above functional groups are shown below. The numbers in parentheses in the names of the functional groups correspond to the numbers in the chemical formulas.

[0037]

[0038]

[0039]

[0040] In the chemical formula, the positions where the (meth)acrylic acid backbone bonds to the ring structure of Q are shown as representative examples, but are not limited thereto. That is, the (meth)acrylic acid backbone can bond to any atom constituting the ring structure of Q.

[0041] Q is preferably not to have unsaturated bonds, and is preferably an oxetane group (4), tetrahydrofurfuryl group (6), tietanyl group (15), tetrahydropyranyl group (9), dioxolanyl group (10), dioxaneyl group (11), oxathiolanyl group (18), morpholino group (14), etc.

[0042] Specific examples of vinyl monomers forming a structural unit (a-1) represented by general formula (1) include tetrahydrofurfuryl(meth)acrylate, morpholino(meth)acrylate, morpholinoethyl(meth)acrylate, (3-ethyloxetane-3-yl)methyl(meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methyl(meth)acrylate, cyclic trimethylolpropaneformal(meth)acrylate, 2-[(2-tetrahydropyranyl)oxy]ethyl(meth)acrylate, 1,3-dioxane-(meth)acrylate, etc.

[0043] Block A may have only one type of structural unit (a-1) represented by general formula (1), or may have two or more types of structural units (a-1) represented by general formula (1).

[0044] The structural unit (a-1) represented by general formula (1) has a cyclic ether group or a cyclic thioether group that has high affinity for epoxy resin, thereby increasing the compatibility of block A with the epoxy resin.

[0045] The content of the structural unit (a-1) represented by the general formula (1) in each A block is 85 mass% or more, preferably 87 mass% or more, more preferably 88 mass% or more, more preferably 89 mass% or more, less than 100 mass%, preferably 99 mass% or less, more preferably 98 mass% or less, and more preferably 97 mass% or less. By setting the content of the structural unit (a-1) to the above range, the compatibility of the A block with the epoxy resin is improved, and since the B block can be dispersed in the epoxy resin at a nanoscale, the cured product of the obtained epoxy resin composition exhibits high transparency.

[0046] The content of the above structural unit (a-1) in each A block is the content in each of the A block at one end and the A block at the other end of the block copolymer.

[0047] Block A has, in addition to the structural unit (a-1) represented by the general formula (1) described above, a structural unit (a-2) derived from a (meth)acrylate having additional chain-like alkyl groups. The structural unit (a-2) has lower affinity with the epoxy resin compared to the structural unit (a-1).

[0048] Examples of chain alkyl groups having a (meth)acrylate having a chain alkyl group constituting the structural unit (a-2) include straight-chain alkyl groups and branched-chain alkyl groups. Examples of the straight-chain alkyl groups include methyl groups, ethyl groups, n-propyl groups, n-butyl groups, n-pentyl groups, n-hexyl groups, n-heptyl groups, n-octyl groups, n-nonyl groups, n-decyl groups, etc. Examples of the branched-chain alkyl groups include isopropyl groups, isobutyl groups, sec-butyl groups, tert-butyl groups, isopentyl groups, sec-pentyl groups, tert-pentyl groups, neopentyl groups, isohexyl groups, sec-hexyl groups, tert-hexyl groups, 2-ethylhexyl groups, isoheptyl groups, isooctyl groups, isononyl groups, isodecyl groups, etc. Among these, a chain alkyl group having 1 to 10 carbon atoms is preferred, a straight chain alkyl group having 1 to 10 carbon atoms and / or a branched chain alkyl group having 3 to 10 carbon atoms is more preferred, and a branched chain alkyl group having 3 to 10 carbon atoms is even more preferred. This is because using a (meth)acrylate having such a chain alkyl group makes it easy to achieve good compatibility with the epoxy resin of block A, while also ensuring that the affinity with the epoxy resin of block A falls within a suitable range.

[0049] Block A may have only one type of structural unit (a-2), or may have two or more types of structural units (a-2).

[0050] The content of the structural unit (a-2) in each A block is greater than 0 mass%, preferably 1 mass% or more, more preferably 2 mass% or more, more preferably 3 mass% or more, 15 mass% or less, preferably 13 mass% or less, more preferably 12 mass% or less, and more preferably 11 mass% or less. By setting the content of the structural unit (a-2) to the above range, the affinity of the A block with the epoxy resin is appropriate, and since the B block can be dispersed in the epoxy resin in a nano-sized string-shaped dispersion state, the cured product of the obtained epoxy resin composition has excellent fracture toughness and peel adhesion.

[0051] In addition, the content of the above structural unit (a-2) in each A block is the content in each of the A block at one end and the A block at the other end of the block copolymer.

[0052] Block A may be composed only of the structural units (a-1) and (a-2) described above, or may include other structural units (a-3) within a range that maintains appropriate affinity for the epoxy resin of Block A.

[0053] Other structural units (a-3) that may be included in block A are not particularly limited as long as they are formed by a vinyl monomer that forms a structural unit (a-1) represented by general formula (1), a (meth)acrylate having a chain alkyl group that forms a structural unit (a-2), and a vinyl monomer that can copolymerize with the vinyl monomer that forms block B described later. Specific examples of vinyl monomers that can form other structural units (a-3) of block A include aromatic vinyl monomers, vinyl monomers having hydroxyl groups, vinyl monomers having carboxyl groups, vinyl monomers having sulfonic acid groups, vinyl monomers having phosphate groups, vinyl monomers containing tertiary amines, vinyl monomers containing quaternary ammonium bases, vinyl monomers containing heterocyclic groups, vinylamides, vinyl monomers containing epoxy groups, vinyl carboxylates, α-olefins, dienes, (meth)acrylate monomers, etc.

[0054] Examples of aromatic vinyl monomers include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, 1-vinylnaphthalene, etc.

[0055] Examples of vinyl monomers having hydroxyl groups include hydroxyalkyl (meth)acrylates.

[0056] Examples of vinyl monomers having a carboxyl group include monomers obtained by reacting an acid anhydride such as maleic anhydride, succinic anhydride, or phthalic anhydride with the vinyl monomer having a hydroxyl group, as well as crotonic acid, maleic acid, itaconic acid, (meth)acrylic acid, etc.

[0057] Examples of vinyl monomers having a sulfonic acid group include vinyl sulfonic acid, styrene sulfonic acid, ethyl (meth)acrylate disulfonate, methylpropyl sulfonic acid (meth)acrylamide, ethyl (meth)acrylamide sulfonate, etc.

[0058] Examples of vinyl monomers having a phosphate group include methacryloyloxyethyl phosphate ester.

[0059] Examples of vinyl monomers containing tertiary amines include N,N-dimethylaminopropyl(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylamide, 2-(dimethylamino)ethyl(meth)acrylate, N,N-dimethylaminopropyl(meth)acrylate, etc.

[0060] Examples of vinyl monomers containing quaternary ammonium bases include N-2-hydroxy-3-acryloyloxypropyl-N,N,N-trimethylammonium chloride, N-methacryloylaminoethyl-N,N,N-dimethylbenzylammonium chloride, etc.

[0061] Examples of vinyl monomers containing heterocyclic groups include 2-vinylthiophene, N-methyl-2-vinylpyrrole, 1-vinyl-2-pyrrolidone, 2-vinylpyridine, 4-vinylpyridine, etc.

[0062] Examples of vinylamides include N-vinylformamide, N-vinylacetamide, and N-vinyl-ε-caprolactam.

[0063] Examples of vinyl monomers containing epoxy groups include glycidyl (meth)acrylate.

[0064] Examples of vinyl carboxylates include vinyl acetate, vinyl pivalate, vinyl benzoate, etc. Examples of α-olefins include 1-hexene, 1-octene, 1-decene, etc. Examples of dienes include butadiene, isoprene, 4-methyl-1,4-hexadiene, 7-methyl-1,6-octadiene, etc.

[0065] Examples of (meth)acrylate monomers include (meth)acrylates having a cyclic alkyl group, (meth)acrylates having a hydroxyl group, (meth)acrylates having an alkoxy group, (meth)acrylates having a sulfonic acid group, (meth)acrylates containing a tertiary amine, (meth)acrylates containing an epoxy group, (meth)acrylates having a polyethylene glycol structural unit, (meth)acrylates having an aromatic group, and (meth)acrylamide.

[0066] Examples of (meth)acrylates having a cyclic alkyl group include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, etc.

[0067] Examples of (meth)acrylates having a hydroxyl group include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0068] Examples of (meth)acrylates having an alkoxy group include methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate.

[0069] Examples of (meth)acrylates having a sulfonic acid group include ethyl (meth)acrylate disulfonate.

[0070] Examples of tertiary amine-containing (meth)acrylates include 2-(dimethylamino)ethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc.

[0071] Examples of (meth)acrylates containing epoxy groups include glycidyl (meth)acrylate.

[0072] Examples of (meth)acrylates having polyethylene glycol structural units include diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, etc.

[0073] Examples of (meth)acrylates having directional ventilation include benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, etc.

[0074] Examples of (meth)acrylamides include (meth)acrylamide, N-methyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, etc.

[0075] Vinyl monomers capable of forming structural units (a-3) may be used alone or in combination of two or more.

[0076] When block A has a structural unit (a-3), the content of the structural unit (a-3) in each block A is preferably 10 mass% or less, more preferably 8 mass% or less, even more preferably 6 mass% or less, and particularly preferably 5 mass% or less in each block A of 100 mass%. In addition, the lower limit of the content of the structural unit (a-3) is 0 mass%.

[0077] In addition, the content of the above structural unit (a-3) in each A block is the content in each of the A block at one end and the A block at the other end of the block copolymer.

[0078] In addition, it is preferable that block A does not substantially contain the structural unit (b) of block B. That is, in block A, the content of the structural unit (b) of block B is preferably 10 mass% or less, more preferably 8 mass% or less, even more preferably 5 mass% or less, and particularly preferably 2 mass% or less in each block A at 100 mass%. In addition, the lower limit of the above content is 0 mass%.

[0079] In cases where two or more structural units are contained in block A, the various structural units contained in block A may be contained in block A in any form, such as random copolymerization or block copolymerization, and from the perspective of uniformity, it is preferable that they be contained in block A in the form of random copolymerization. For example, block A may be formed by a copolymer of a block composed of (a-1) structural units and a block composed of (a-2) structural units.

[0080] (Block B)

[0081] Block B is a polymer block having a structural unit (b) derived from at least one vinyl monomer selected from the group consisting of (meth)acrylates having a chain alkyl group and (meth)acrylates having a cyclic alkyl group. Block B is thought to have lower compatibility with epoxy resin compared to Block A in that it substantially does not contain the structural unit (a-1) derived from the vinyl monomer.

[0082] Examples of (meth)acrylates having a chain alkyl group include dodecyl (meth)acrylate (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate (stearyl (meth)acrylate), nonadecyl (meth)acrylate, etc. Among these, a (meth)acrylate having a chain alkyl group having 11 to 20 carbon atoms is preferred. In addition, the chain alkyl group may be either a straight-chain alkyl group or a branched-chain alkyl group, but it is preferred to be a straight-chain alkyl group.

[0083] Examples of (meth)acrylates having a cyclic alkyl group include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, ethylcyclohexyl (meth)acrylate, butylcyclohexyl (meth)acrylate, pentylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, etc. Among these, a (meth)acrylate having a cyclic alkyl group having 6 to 15 carbon atoms (particularly a monocyclic alkyl group) is preferred.

[0084] The above vinyl monomer may be used alone or in combination of two or more types.

[0085] As a vinyl monomer forming structural unit (b), it is particularly preferable to use a (meth)acrylate having a chain alkyl group, more preferably to use a (meth)acrylate having a chain alkyl group having 11 to 20 carbon atoms, even more preferably to use a (meth)acrylate having a straight-chain alkyl group having 11 to 20 carbon atoms, and especially preferable to use a (meth)acrylate having a straight-chain alkyl group having 11 to 15 carbon atoms. This is because by using a (meth)acrylate having a chain alkyl group having 11 to 20 carbon atoms as a vinyl monomer forming structural unit (b), the B block becomes flexible, and the energy dispersal effect during crack extension is further improved, thereby obtaining a cured product of an epoxy resin composition with improved fracture toughness and peel adhesion.

[0086] The content of structural unit (b) is preferably 80 mass% or more, more preferably 90 mass% or more, more preferably 95 mass% or more, and particularly preferably 98 mass% or more, out of 100 mass% of the total B block. In addition, the upper limit of the content of the structural unit (b) is 100 mass%. By setting the content of the structural unit (b) to the above range, a cured product of an epoxy resin composition with improved fracture toughness and peel adhesion is obtained.

[0087] Block B may consist solely of structural unit (b), or may include other structural units within a range that maintains low compatibility with the epoxy resin of Block B. Additionally, it is preferable that Block B substantially does not contain structural units (a-1) and (a-2) of Block A. That is, in Block B, the content of each of structural units (a-1) and (a-2) of Block A is preferably 10 mass% or less, more preferably 8 mass% or less, even more preferably 5 mass% or less, and particularly preferably 2 mass% or less, out of 100 mass% of Block B. Furthermore, the lower limit of the above content is 0 mass%.

[0088] Specific examples of vinyl monomers capable of forming other structural units of block B include aromatic vinyl monomers, vinyl monomers having hydroxyl groups, vinyl monomers having carboxyl groups, vinyl monomers having sulfonic acid groups, vinyl monomers having phosphate groups, vinyl monomers containing tertiary amines, vinyl monomers containing quaternary ammonium bases, vinyl monomers containing heterocyclic groups, vinylamides, vinyl monomers containing epoxy groups, vinyl carboxylates, α-olefins, dienes, (meth)acrylic monomers, etc.

[0089] Examples of (meth)acrylate monomers include (meth)acrylates having a hydroxyl group, (meth)acrylates having an alkoxy group, (meth)acrylates having a sulfonic acid group, (meth)acrylates containing a tertiary amine, (meth)acrylates containing an epoxy group, (meth)acrylates having a polyethylene glycol structural unit, (meth)acrylates having an aromatic group, and (meth)acrylamide.

[0090] Specific examples of the above vinyl monomer include the same as those exemplified as specific examples of vinyl monomers capable of forming other structural units (a-3) of block A.

[0091] The vinyl monomers used in Block B may each be one or two or more types.

[0092] The content of other structural units of Block B is preferably 20 mass% or less, more preferably 10 mass% or less, and even more preferably 5 mass% or less, out of 100 mass% of the total Block B. In addition, the lower limit of the content of other structural units of Block B is 0 mass%.

[0093] In cases where two or more structural units are contained in the B block, the various structural units contained in the B block may be contained in the B block in any form, such as random copolymerization or block copolymerization, and from the perspective of uniformity, it is preferable that they be contained in the form of random copolymerization.

[0094] (Block copolymer)

[0095] The block copolymer contained in the epoxy resin modifier of the present invention is an ABA-type triblock copolymer (A represents "A block" and B represents "B block"). By using an ABA-type triblock copolymer, the B block can be dispersed in the epoxy resin in a more uniform string shape, thereby enabling high peel adhesion and fracture toughness.

[0096] In Block A, the type or content of each constituent unit of Block A at one end may be the same as or different from the type or content of each constituent unit of Block A at the other end.

[0097] In an ABA-type triblock copolymer, when the content of structural unit (a-1) differs between the A block at one end and the A block at the other end, the block with a higher content of structural unit (a-1) is designated as the A1 block, and the block with a lower content of structural unit (a-1) is designated as the A2 block.

[0098] The mass ratio of A1 block and A2 block (A1 block / A2 block) is not particularly limited, but is preferably 0.8 or higher, more preferably 0.85 or higher, preferably 1.2 or lower, more preferably 1.15 or lower, and even more preferably 1.1 or lower. By adjusting the mass ratio of A1 block and A2 block (A1 block / A2 block) to within the above range, the island portion consisting of B block can be dispersed in the epoxy resin in a more uniform nano size, so a cured product of an epoxy resin composition with improved peel adhesion and fracture toughness can be obtained while maintaining transparency.

[0099] The content of block A (i.e., the total content of block A1 and block A2) is preferably 30 mass% or more, more preferably 35 mass% or more, more preferably 40 mass% or more, particularly preferably 45 mass% or more, preferably 70 mass% or less, more preferably 65 mass% or less, more preferably 60 mass% or less, and particularly preferably 55 mass% or less, in the total 100 mass% of the block copolymer. By adjusting the content of block A to within the above range, a block copolymer having the intended function can be produced.

[0100] The content of the B block is preferably 30 mass% or more, more preferably 35 mass% or more, more preferably 40 mass% or more, particularly preferably 45 mass% or more, preferably 70 mass% or less, more preferably 65 mass% or less, more preferably 60 mass% or less, and particularly preferably 55 mass% or less, out of 100 mass% of the total block copolymer. By adjusting the content of the B block to within the above range, a block copolymer having the intended function can be produced.

[0101] The weight average molecular weight (Mw) of the block copolymer is preferably 10,000 or more, more preferably 20,000 or more, more preferably 30,000 or more, particularly preferably 35,000 or more, less than 200,000, more preferably less than 100,000, more preferably less than 80,000, and particularly preferably less than 50,000. If the weight average molecular weight is below the lower limit, the peel adhesion and fracture toughness imparted are insufficient, and if it is above the upper limit, the solubility with respect to the epoxy resin decreases. Therefore, if the weight average molecular weight is within the above range, a cured product of an epoxy resin composition with improved peel adhesion and fracture toughness can be obtained while maintaining transparency.

[0102] The molecular weight distribution (Mw / Mn) of the above block copolymer is preferably 2.0 or less, more preferably 1.6 or less, and even more preferably 1.5 or less. Furthermore, in the present invention, the molecular weight distribution (Mw / Mn) is determined by (weight average molecular weight (Mw) of the block copolymer) / (number average molecular weight (Mn) of the block copolymer). The smaller the Mw / Mn, the narrower the molecular weight distribution, resulting in a uniformly molecular copolymer, and the narrowest molecular weight distribution occurs when the value is 1.0. If the molecular weight distribution (Mw / Mv) of the above block copolymer exceeds 2.0, it includes molecules with small or large molecular weights. This is because if the molecular weight is small, the peel adhesion and fracture toughness are insufficient, and if the molecular weight is large, the solubility with respect to the epoxy resin decreases, which may lead to a lack of transparency and a risk of reduced mechanical strength.

[0103] In addition, in the present invention, the weight average molecular weight and number average molecular weight are measured by gel permeation chromatography (hereinafter referred to as "GPC").

[0104] (Method for manufacturing block copolymers)

[0105] As a method for manufacturing the above block copolymer, a first block A (e.g., block A1) may be first manufactured by a polymerization reaction of vinyl monomers, a monomer of block B may be polymerized into the first block A, and a monomer of block 2 A (e.g., block A2) may be polymerized into block B; or, the first block A (e.g., block A1), the second block A (e.g., block A2), and block B may be manufactured separately, and then the first block A, block B, and block 2 A may be coupled.

[0106] For example, it is obtained by sequentially polymerizing vinyl monomers constituting the block using a radical polymerization method. Specifically, a manufacturing method may be provided comprising: a process of synthesizing Block 1A by polymerizing vinyl monomers constituting Block 1A (e.g., Block A1); a process of synthesizing Block B by polymerizing vinyl monomers constituting Block B into the synthesized Block 1A; and a process of synthesizing Block 2A by polymerizing vinyl monomers constituting Block 2A (e.g., Block A2) into the synthesized Block B.

[0107] The polymerization method is not particularly limited, but living radical polymerization is preferred. That is, the block copolymer is preferably polymerized by living radical polymerization. Conventional radical polymerization methods tend to result in a mixture of polymers with various molecular weights and heterogeneous compositions, as the loss of activity at the growth ends occurs due to termination reactions and chain transfer reactions, in addition to the initiation and growth reactions. The living radical polymerization method is preferred because it maintains the simplicity and versatility of conventional radical polymerization methods, while making it difficult for termination reactions or chain transfers to occur and allowing growth without the loss of activity at the growth ends, thereby facilitating precise control of molecular weight distribution and the production of polymers with a uniform composition.

[0108] Living radical polymerization methods include a method using a compound capable of generating nitroxide radicals based on a difference in the method of stabilizing the polymerization growth end (nitroxide method (NMP method)); a method using a metal complex such as copper or ruthenium, using a halogenated compound as a polymerization initiator, and polymerizing from the polymerization initiator (ATRP method); a method using a dithiocarboxylic acid ester or xanthate compound (RAFT method); a method using an organic tellurium compound (TERP method); a method using an organic iodine compound (ITP method); and a method using an iodine compound as a polymerization initiator and using an organic compound such as a phosphorus compound, nitrogen compound, oxygen compound, or hydrocarbon as a catalyst (reversible transfer catalytic polymerization (RTCP method), reversible catalyst-mediated polymerization (RCMP method)). Among these methods, it is preferable to use the TERP method in terms of the diversity of monomers that can be used, molecular weight control in the polymer region, uniform composition, or coloring.

[0109] Living radical polymerization, particularly the TERP method, is desirable because the polymer chains react uniformly with the monomers during polymerization, the composition of all polymers becomes closer to uniform, and the probability of forming pseudo-crosslinks increases.

[0110] The TERP method is a method of polymerizing a radical polymerizable compound (vinyl monomer) using an organic tellurium compound as a polymerization initiator, and is, for example, the method described in International Publication No. 2004 / 14848, International Publication No. 2004 / 14962, International Publication No. 2004 / 072126, and International Publication No. 2004 / 096870.

[0111] Specific polymerization methods of the TERP method include the following (a) to (d).

[0112] (a) A method of polymerizing a vinyl monomer using an organic tellurium compound represented by the general formula (2).

[0113] (b) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by general formula (2) and an azo polymerization initiator.

[0114] (c) A method of polymerizing vinyl monomers using a mixture of an organic tellurium compound represented by general formula (2) and an organic ditellurium compound represented by general formula (3).

[0115] (d) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by general formula (2), an azo polymerization initiator, and an organic ditellurium compound represented by general formula (3).

[0116]

[0117] [In general formula (2), R 3 It represents a carbon-1 to carbon-8 alkyl group, an aryl group, or an aromatic heterocyclic group. R 4 and R 5 represents, respectively, a hydrogen atom or a C1-C8 alkyl group. 6 It represents an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group, or a propargyl group.

[0118] [In general formula (3), R 7 It represents a carbon-1 to carbon-8 alkyl group, aryl group, or aromatic heterocyclic group.

[0119] R 3The group represented by is an alkyl group, an aryl group, or an aromatic heterocyclic group having 1 to 8 carbon atoms, and specifically is as follows. Examples of alkyl groups having 1 to 8 carbon atoms include straight-chain or branched-chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl groups, or cyclic alkyl groups such as cyclohexyl groups. Preferably, it is a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, and more preferably, it is a methyl group or an ethyl group. Examples of aryl groups include phenyl groups, naphthyl groups, etc. Examples of aromatic heterocyclic groups include pyridyl groups, furyl groups, thienyl groups, etc.

[0120] R 4 and R 5 The group represented by is independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and each group is specifically as follows. Examples of alkyl groups having 1 to 8 carbon atoms include straight-chain or branched-chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl groups, or cyclic alkyl groups such as cyclohexyl groups. Preferably, it is a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, and more preferably, it is a methyl group or an ethyl group.

[0121] R 6 The group represented by is an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group, or a propargyl group, and specifically is as follows.

[0122] Examples of alkyl groups having 1 to 8 carbon atoms include straight-chain or branched-chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl groups, and cyclic alkyl groups such as cyclohexyl. Preferably, it is a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, and more preferably, it is a methyl or ethyl group.

[0123] Examples of aryl groups include phenyl groups, naphthyl groups, etc. Preferably, it is a phenyl group.

[0124] Examples of substituted aryl groups include substituents such as phenyl groups and naphthyl groups. Examples of substituents for aryl groups include halogen atoms, hydroxyl groups, alkoxy groups, amino groups, nitro groups, cyano groups, and -COR groups. 61 A carbonyl containing group (R) represented by 61 Examples include C1-8 alkyl groups, aryl groups, C1-8 alkoxy groups or aryloxy groups), sulfonyl groups, trifluoromethyl groups, etc. In addition, it is preferable that one or two of these substituents are substituted.

[0125] Examples of aromatic heterocyclic groups include pyridyl groups, furyl groups, and thienyl groups.

[0126] As for the alkoxy group, a carbon-1 to carbon-8 alkyl group bonded to an oxygen atom is preferred, and examples include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, etc.

[0127] Examples of acyl groups include acetyl groups, propionyl groups, and benzoyyl groups.

[0128] As an amide group, -CONR 621 R 622 (R 621 , R 622Examples include hydrogen atoms, carbon 1-8 alkyl groups, or aryl groups, each independently.

[0129] As for the oxycarbonyl group, -COOR 63 (R 63 A group represented by a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group is preferred, and examples include a carboxyl group, a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, an n-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert-butoxycarbonyl group, an n-pentoxycarbonyl group, a phenoxycarbonyl group, etc. Preferred oxycarbonyl groups include a methoxycarbonyl group and an ethoxycarbonyl group.

[0130] As for an announcement, -CR 641 R 642 -CR 643 =CR 644 R 645 (R 641 , R 642 is, each independently a hydrogen atom or a C1-C8 alkyl group, R 643 , R 644 , R 645 Examples include each being independently a hydrogen atom, a carbon-1 to carbon-8 alkyl group, or an aryl group, and each substituent may be connected in a cyclic structure.

[0131] As for the propargil, -CR 651 R 652 -C≡CR 653 (R 651 , R 652 is a hydrogen atom or a C1-C8 alkyl group, R 653 Examples include silver, hydrogen atoms, alkyl groups having 1 to 8 carbon atoms, aryl groups, or silyl groups.

[0132] Organic tellurium compounds represented by general formula (2) can specifically be exemplified by all organic tellurium compounds described in International Publication No. 2004 / 14848, International Publication No. 2004 / 14962, International Publication No. 2004 / 072126, and International Publication No. 2004 / 096870, including (methyltellanylmethyl)benzene, (methyltellanylmethyl)naphthalene, ethyl=2-methyl-2-methyltellanyl-propionate, ethyl=2-methyl-2-n-butyltellanyl-propionate, (2-trimethylsiloxyethyl)=2-methyl-2-methyltellanyl-propionate or (3-trimethylsilylpropargyl)=2-methyl-2-methyltellanyl-propionate, etc.

[0133] In general formula (3), R 7 The group represented by is an alkyl group having 1 to 8 carbon atoms, an aryl group, or an aromatic heterocyclic group, and specifically is as follows.

[0134] Examples of alkyl groups having 1 to 8 carbon atoms include straight-chain or branched-chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, and octyl groups, or cyclic alkyl groups such as cyclohexyl groups. Preferably, it is a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, and more preferably, it is a methyl or ethyl group. Examples of aryl groups include phenyl and naphthyl groups. Examples of aromatic heterocyclic groups include pyridyl, furyl, and thienyl groups.

[0135] Organic ditellurium compounds represented by general formula (3) can be specifically exemplified by dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride, diisopropyl ditelluride, dicyclopropyl ditelluride, di-n-butyl ditelluride, di-s-butyl ditelluride, di-t-butyl ditelluride, dicyclobutyl ditelluride, diphenyl ditelluride, bis-(p-methoxyphenyl)ditelluride, bis-(p-aminophenyl)ditelluride, bis-(p-nitrophenyl)ditelluride, bis-(p-cyanophenyl)ditelluride, bis-(p-sulfonylphenyl)ditelluride, dinaphthyl ditelluride, or dipyridyl ditelluride.

[0136] Any azo-based polymerization initiator used in conventional radical polymerization can be used without particular restrictions. For example, 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1'-azobis(1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2'-azobisisobutyrate (MAIB), 4,4'-azobis(4-cyanovalerian acid) (ACVA), 1,1'-azobis(1-acetoxy-1-phenylethane), 2,2'-azobis(2-methylbutylamide), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70), 2,2'-azobis(2-methylamidinopropane) dihydrochloride, Examples include 2,2'-azobis[2-(2-imidazoline-2-yl)propane], 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis(2,4,4-trimethylpentane), 2-cyano-2-propylazoformamide, 2,2'-azobis(N-butyl-2-methylpropionamide), or 2,2'-azobis(N-cyclohexyl-2-methylpropionamide).

[0137] In the polymerization methods of (a), (b), (c) and (d) above, the amount of vinyl monomer used can be appropriately adjusted according to the physical properties of the desired copolymer, but typically, it is preferable to use 5 mol to 10,000 mol of vinyl monomer for every 1 mol of the organic tellurium compound of general formula (2).

[0138] In the above polymerization method (b), when an organic tellurium compound of general formula (2) and an azo polymerization initiator are used together, it is generally preferable to use 0.01 mol to 10 mol of the azo polymerization initiator for every 1 mol of the organic tellurium compound of general formula (2).

[0139] In the above polymerization method (c), when an organic tellurium compound of general formula (2) and an organic ditellurium compound of general formula (3) are used together, the amount of organic ditellurium compound of general formula (3) used is typically 0.01 mol to 100 mol of the organic ditellurium compound of general formula (3) for every 1 mol of the organic tellurium compound of general formula (2).

[0140] In the above polymerization method (d), when an organic tellurium compound of general formula (2), an organic ditellurium compound of general formula (3), and an azo polymerization initiator are used together, the amount of azo polymerization initiator used is typically 0.01 mol to 100 mol for every 1 mol of the total of the organic tellurium compound of general formula (2) and the organic ditellurium compound of general formula (3).

[0141] The polymerization reaction may be carried out without a solvent, or the mixture may be stirred using a non-protonic solvent or a protonic solvent commonly used in radical polymerization. Examples of non-protonic solvents that can be used include benzene, toluene, anisole, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone, acetonitrile, 2-butanone (methyl ethyl ketone), dioxane, hexafluoroisopropanol, propylene glycol monomethyl ether acetate, chloroform, carbon tetrachloride, tetrahydrofuran (THF), N-methyl-2-pyrrolidone (NMP), ethyl acetate, propylene glycol monomethyl ether acetate, or trifluoromethylbenzene. In addition, examples of protonic solvents include water, methanol, ethanol, isopropanol, n-butanol, ethyl cellosolve, butyl cellosolve, 1-methoxy-2-propanol, or diacetone alcohol.

[0142] The amount of solvent used can be appropriately adjusted, for example, in the range of 0.01 ml to 50 ml per 1 g of vinyl monomer, preferably in the range of 0.05 ml to 10 ml, and more preferably in the range of 0.1 ml to 1 ml.

[0143] The reaction temperature and reaction time can be appropriately controlled according to the molecular weight or molecular weight distribution of the resulting copolymer, and typically, stirring is performed at 0°C to 150°C for 1 minute to 100 hours. The TERP method can obtain high yield and a precise molecular weight distribution even at low polymerization temperatures and short polymerization times.

[0144] After the polymerization reaction is completed, the desired copolymer can be separated from the obtained reaction mixture by conventional separation and purification means.

[0145] The growth ends of the copolymer obtained by the polymerization reaction are -TeR derived from tellurium compounds. 3 (during food, R 3It is in the form of the above, and although it loses activity due to handling in air after the polymerization reaction is finished, there are cases where tellurium atoms remain. Since copolymers with tellurium atoms remaining at the ends become discolored or have poor thermal stability, it is desirable to remove the tellurium atoms.

[0146] Methods for removing tellurium atoms include: a radical reduction method using tributylstannan or thiol compounds; a method of adsorption using activated carbon, silica gel, activated alumina, activated clay, molecular sieves, and polymer adsorbents; a method of adsorbing metal using ion exchange resins; a liquid-liquid extraction method or solid-liquid extraction method in which residual tellurium compounds are removed by adding a peroxide such as hydrogen peroxide or benzoyl peroxide, or by blowing air or oxygen into the system to oxidize and decompose the tellurium atoms at the ends of the copolymer, and by washing with water or combining with a suitable solvent; and a purification method in a solution state such as limit filtration to extract and remove only those with a molecular weight of less than or equal to a specific molecular weight. Additionally, these methods may be used in combination.

[0147] Epoxy Resin Modifier

[0148] The epoxy resin modifier of the present invention contains the above-mentioned ABA-type triblock copolymer and is used by incorporating it into an epoxy resin.

[0149] The epoxy resin modifier of the present invention may contain only the ABA-type triblock copolymer, or additionally contain other components. Other components that may be included in the epoxy resin modifier of the present invention include various known additives such as organic solvents, stabilizers, plasticizers, flame retardants, flame retardant aids, antioxidants, and antistatic agents. The organic solvent is not particularly limited, but examples include xylene, toluene, butanol, ethyl acetate, butyl acetate, N,N-dimethylformamide, methyl ethyl ketone, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, cyclohexanone, etc.

[0150] Epoxy Resin Composition

[0151] The epoxy resin composition of the present invention comprises an epoxy resin, a curing agent, and the epoxy resin modifier of the present invention described above.

[0152] As the epoxy resin used in the present invention, any conventionally known epoxy resin may be used. Specific examples include epoxy resins (polyepoxy compounds) containing two or more epoxy groups in a molecule, such as bisphenol-type epoxy resin, phenol novolak-type epoxy resin, orthocresol novolak-type epoxy resin, biphenyl-type epoxy resin, dicyclopentadiene-type epoxy resin, diphenylfluorene-type epoxy resin and their halogens, amino groups, or alkyl substituents, glycidyl ester-type epoxy resin, naphthalene-type epoxy resin, heterocyclic epoxy resin, isocyanate-modified epoxy resin, diarylsulfone-type epoxy resin, hydroquinone-type epoxy resin, hydantoin-type epoxy resin, resorcinol diglycidyl ether, triglycidyl-p-aminophenol, m-aminophenol triglycidyl ether, tetraglycidylmethylenedianiline, (trihydroxyphenyl)methane triglycidyl ether, tetraphenylethane tetraglycidyl ether, etc. The above epoxy resin may be one type or two or more types.

[0153] The above epoxy resin is preferably in a liquid state at room temperature (25°C) in terms of handling and composition adjustment. The epoxy resin that is in a liquid state at room temperature typically has a weight average molecular weight of 300 to 1000 and an epoxy equivalent weight of 150 g / eq to 600 g / eq, and preferably 150 g / eq to 200 g / eq. In addition, among the above epoxy resins, a bisphenol-type epoxy resin is preferably used in terms of handling and processability of the curable resin composition, heat resistance of the resin cured product, fracture toughness, peel adhesion strength, etc. Specific examples of bisphenol-type epoxy resins include bisphenol A-type epoxy resin obtained by the reaction of bisphenol A with epichlorohydrin, bisphenol F-type epoxy resin obtained by the reaction of bisphenol F with epichlorohydrin, bisphenol S-type epoxy resin obtained by the reaction of bisphenol S with epichlorohydrin, bisphenol AD-type epoxy resin obtained by the reaction of bisphenol AD ​​with epichlorohydrin, and halogen or alkyl substituents thereof. Among these, bisphenol A-type epoxy resin is more preferably used in that the handling and processability of the curable resin composition and the heat resistance of the cured resin product are superior, and among them, bisphenol A-type diglycidyl ether is even more preferably used.

[0154] The type of curing agent used in the present invention is not particularly limited, and any conventional curing agent for epoxy resins can be used. Examples of the curing agents include acid anhydride-based curing agents, amine-based curing agents, and phenol-based curing agents. Among these, acid anhydride-based curing agents and amine-based curing agents are preferred, and acid anhydride-based curing agents are more preferred. An acid anhydride-based curing agent is a curing agent having one or more carboxylic acid anhydride groups per molecule, and an epoxy resin composition is cured by a polycondensation reaction between the epoxy group of an epoxy resin, etc., and the carboxylic acid anhydride group. Examples of acid anhydride-based curing agents include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, aliphatic acid anhydrides, etc. Specifically, examples include maleic anhydride, succinic anhydride, phthalic anhydride, 4-methylphthalic anhydride, 4-methylcyclohexanedicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, etc. Amine-based curing agents are curing agents having one or more amine groups per molecule, and an epoxy resin composition is cured by a polycondensation reaction between an epoxy group and an amine group of an epoxy resin, etc. Examples of amine-based curing agents include cyclic aliphatic amines, aromatic amines, aliphatic amines, etc. Specifically, examples include diethylenetriamine, triethylenetetramine, methaxylylenediamine, diaminodiphenylmethane, methanephenylenediamine, diaminodiphenylsulfone, etc. Examples of the above-mentioned phenolic curing agents include phenol novolak resin. These curing agents may be used alone or in combination of two or more types.

[0155] The content of the above curing agent is not particularly limited, but with respect to 100 parts by mass of epoxy resin, it is preferably 5 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 50 parts by mass or more, particularly preferably 70 parts by mass or more, preferably 250 parts by mass or less, more preferably 200 parts by mass or less, and even more preferably 150 parts by mass or less. In addition, the amount of the above curing agent is preferably 0.5 to 2.5 equivalents with respect to the epoxy groups in the epoxy resin composition, and is more preferably 0.5 to 1.5 equivalents. This is because if the content of the curing agent is within the above range, the mechanical properties of the cured product of the epoxy resin composition are improved.

[0156] The epoxy resin composition of the present invention preferably further contains a curing accelerator. Specific examples of the curing accelerator include, for example, benzyldimethylamine, cyclohexyldimethylamine, pyridine, triethanolamine, 2-(dimethylaminomethyl)phenol, dimethylpiperazine, 1,8-diazabicyclo[5,4,0]undec-7-en (DBU), 1,5-diazabicyclo[4,3,0]nona-5-en (DBN), 1,4-diazabicyclo[2,2,2]octane (DABCO), 2,4,6-tris(dimethylaminomethyl)phenol, and tertiary amine compounds; 2-methylimidazole, 2-ethylimidazole, 2-n-heptylimidazole, 2-n-undecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1-(2-cyanoethyl)-2-methylimidazole, 1-(2-cyanoethyl)-2-n-undecylimidazole, 1-(2-cyanoethyl)-2-phenylimidazole, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-di(hydroxymethyl)imidazole, 1-(2-cyanoethyl)-2-phenyl-4,5-di((2'-cyanoethoxy)methyl)imidazole, 1-(2-cyanoethyl)-2-n-undecylimidazolium trimellitate, 1-(2-cyanoethyl)-2-phenylimidazolium trimellitate, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazolium trimellitate, 2,4-diamino-6-(2'-methylimidazolyl-(1'))ethyl-s-triazine, 2,4-diamino-6-(2'-n-undecylimidazolyl)ethyl-s-triazine, 2,4-diamino-6-(2'-ethyl-4'-methylimidazolyl-(1'))ethyl-s-triazine, asocyanuric acid adduct of 2-methylimidazole, Examples include imidazole compounds such as isocyanuric acid adducts of 2-phenylimidazole and isocyanuric acid adducts of 2,4-diamino-6-(2'-methylimidazolyl-(1'))ethyl-s-triazine; phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium and tetraphenylborate; metal compounds such as tin octylate, and microcapsule-type curing accelerators.These may be used individually or in combination of two or more types.

[0157] The content of the above-mentioned curing accelerator is not particularly limited, but it is preferable to have 0.1 to 5 parts by mass per 100 parts by mass of epoxy resin, more preferable to have 0.2 to 2 parts by mass, and even more preferable to have 0.5 to 1.5 parts by mass. This is because if the content of the curing accelerator is within the above range, the mechanical properties of the cured product of the epoxy resin composition are improved.

[0158] In the epoxy resin composition of the present invention, the content of the epoxy resin modifier of the present invention, in terms of the equivalent amount of ABA-type triblock copolymer, is preferably 1 part by mass or more, more preferably 3 parts by mass or more, more preferably 5 parts by mass or more, preferably 25 parts by mass or less, more preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and particularly preferably 10 parts by mass or less, with respect to 10 parts by mass or less. If the content of the epoxy resin modifier is 1 part by mass or more, a cured product of the epoxy resin composition with excellent fracture toughness and peel adhesion is obtained. In addition, if the content of the epoxy resin modifier is 25 parts by mass or less, it is possible to suppress the deterioration of the epoxy resin's function (tensile strength, solvent resistance, etc.) associated with the addition of a large amount of the epoxy resin modifier while maintaining high transparency.

[0159] The epoxy resin composition of the present invention may contain, in addition to the epoxy resin, curing agent, curing accelerator, and epoxy resin modifier of the present invention, other additives as needed within a range that does not impair the effects of the present invention. For example, reactive diluents such as n-butanol glycidyl ether, butyl glycidyl ether, butylphenyl glycidyl ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, tetrahydrofurfuryl glycidyl ether, furfuryl glycidyl ether, trimethoxysilyl glycidyl ether, other higher alcohol-based glycidyl ethers, methacrylic acid glycidyl esters, etc., or polyfunctional forms of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, dimer acid diglycidyl ester, etc.; thixotropic agents (thixotropic agents) such as carbon black such as Ketjen black, silica, fine calcium carbonate, sepiolite, etc.; Calcium carbonate, talc, magnesia, calcium silicate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, alumina, zircon, graphite, barium sulfate, clay, mica, kaolin, wollastonite, mica, feldspar, syenite (syaenite), chlorite (chlorite), bentonite, montmorillonite, balite, cristobalite, dolomite, quartz, diatomite, aluminum silicate, barium carbonate, magnesium carbonate, zinc carbonate, mineral fibers, textile fibers, glass fibers, aramid pulp, boron fibers, carbon fibers, phosphates, silica such as crystalline silica, amorphous silica, fused silica, fumed silica, calcined silica, precipitated silica, and ground (fine powder) silica, pyrophyllite, silica sand, cellulose, cement, resin powders such as polyethylene, calcium oxide, iron oxide, zinc oxide, titanium oxide, barium oxide, Fillers such as magnesium oxide, titanium dioxide, hollow inorganic beads such as hollow ceramic beads, hollow glass beads, hollow organic beads made of polyester resin, glass beads, metal powder, bituminous material, etc.; reaction retardants; anti-aging agents; antioxidants; plasticizers; adhesion promoters;Examples include flame retardants; antistatic agents; UV absorbers; surfactants; dispersants; defoaming agents; rheology modifiers; polymerization inhibitors; pigments; dyes; coupling agents; ion supplements; release agents; thermosetting resins other than epoxy resins; thermoplastic resins, etc.;

[0160] The epoxy resin composition of the present invention preferably contains a reactive diluent. As reactive diluents, 1,6-hexanediol diglycidyl ether and butylglycidyl ether are preferred. The content of the reactive diluent in the epoxy resin composition is preferably 0.1 mass% or more, more preferably 1 mass% or more, preferably 10 mass% or less, and more preferably 7 mass% or less. If the content of the reactive diluent is within the above range, the viscosity of the epoxy resin composition can be lowered while maintaining excellent fracture toughness.

[0161] The method for manufacturing the epoxy resin composition of the present invention is not particularly limited, and any manufacturing method capable of uniformly mixing the epoxy resin, the curing agent, the epoxy resin modifier of the present invention, and, if necessary, a curing accelerator or other additives may be employed. For example, the epoxy resin composition of the present invention may be manufactured by employing the following methods: (1) introducing the epoxy resin into a reactor, and if the epoxy resin is solid, heating it to a suitable temperature to make it liquid, adding the epoxy resin modifier thereto to dissolve it, adding the curing agent or curing accelerator thereto to uniformly mix it in a liquid form, and, if necessary, performing a degassing treatment; (2) uniformly mixing the epoxy resin, the curing agent or curing accelerator, and the epoxy resin modifier using a mixer, etc., and then melt-kneading using a hot roll, a twin-screw extruder, a kneader, etc. to manufacture the epoxy resin composition; (3) dissolving the epoxy resin, the curing agent or curing accelerator, and the epoxy resin modifier in a solvent such as methyl ethyl ketone, acetone, or toluene to manufacture a varnish-shaped epoxy resin composition.

[0162] Adhesive

[0163] The epoxy resin composition of the present invention is useful as an adhesive in that it can impart excellent peel adhesion. Examples of applications for the adhesive of the present invention include structural applications for vehicles such as automobiles, civil engineering and construction, electronic materials, general office use, medical use, industrial use, etc.

[0164] Underfill

[0165] In the manufacture of electronic devices such as semiconductor devices, semiconductor chip mounting is performed by connecting components such as a substrate and a semiconductor chip, or semiconductor chips and semiconductor chips, to each other using solder bumps. In this semiconductor chip mounting, an encapsulating material (underfill material) is used to fill the gaps between the components. The epoxy resin composition of the present invention is useful as such an underfill material in that it can impart excellent peel adhesion and fracture toughness. Applications of the underfill material of the present invention include semiconductor chip mounting. More specifically, it can be suitably used for filling gaps between a semiconductor chip connected by solder bumps and a substrate, or gaps between semiconductor chips.

[0166] The underfill material of the present invention is preferably in a liquid state at room temperature (25°C). The viscosity of the underfill material of the present invention at room temperature (25°C) is preferably 500 mPa·s or higher, more preferably 1500 mPa·s or higher, even more preferably 2500 mPa·s or higher, preferably 6000 mPa·s or lower, more preferably 4500 mPa·s or lower, and even more preferably 3000 mPa·s or lower. This is because if the viscosity of the underfill material is within the above range, the resin can easily penetrate between the substrate and the semiconductor chip quickly and without gaps, and at the same time, prevent the resin from diffusing between penetration and curing. In addition, the viscosity is measured by the method described later.

[0167] <Curing Resin>

[0168] The resin cured product of the present invention is formed by curing the epoxy resin composition of the present invention described above.

[0169] In preparing a resin-cured product using the above epoxy resin composition, any of the conventional curing methods for epoxy resin compositions may be employed. For example, heat curing, energy beam curing (electron beam curing, ultraviolet curing, etc.), and moisture curing methods may all be employed, and among these, heat curing is preferred from the perspective of dispersion of the block copolymer.

[0170] When the epoxy resin composition of the present invention is in a solid state at room temperature (25°C), for example, after grinding and tableting, a resin cured product (cured molded product) can be manufactured by curing molding using conventional molding methods such as transfer molding, compression molding, and injection molding.

[0171] In addition, when the epoxy resin composition of the present invention exhibits a liquid or varnish form at room temperature (25°C), for example, the epoxy resin composition of the present invention can be carried out by a suitable method such as pouring it into a mold (molding), pouring it into a container (potting, etc.), applying it onto a substrate (lamination), or impregnating it into a fiber (filament, etc.) (filament winding, etc.), and then heat-curing it to obtain a resin cured product according to each application.

[0172] The curing temperature and curing time when curing the epoxy resin composition of the present invention may vary depending on the type of epoxy resin or curing agent, but for example, conditions such as a curing temperature of 20°C to 250°C and a curing time of 1 to 24 hours are adopted.

[0173] The light transmittance of the resin cured product of the present invention is preferably 30% or more when the light transmittance of the cured product of the epoxy resin composition that does not incorporate the epoxy resin modifier of the present invention is set to 100%, it is more preferably 35% or more, and even more preferably 40% or more. This is because making the light transmittance 30% or more results in a resin cured product with excellent transparency.

[0174] The peel adhesion strength (N / 25mm) of the resin cured product of the present invention is preferably 3.5 or higher, more preferably 5.0 or higher, and even more preferably 10.0 or higher. This is because setting the peel adhesion strength (N / 25mm) to 3.5 or higher results in a resin cured product with excellent peel adhesion properties.

[0175] Fracture toughness (MPa·m) of the resin cured product of the present invention 1 / 2 ) is preferably 0.7 or higher, more preferably 0.8 or higher, and even more preferably 0.9 or higher. Fracture toughness (MPa·m 1 / 2 This is because making ) 0.7 or higher results in a resin cured product with excellent fracture toughness.

[0176] The coefficient of linear expansion for the peel adhesion of the resin cured product of the present invention (coefficient of linear expansion α1 / peele adhesion) is preferably 0.6 or higher, more preferably 0.8 or higher, even more preferably 1 or higher, preferably 15 or lower, even more preferably 10 or lower, and even more preferably 5 or lower. This is because if the coefficient of linear expansion for the peel adhesion is within the above range, the temperature cycling resistance is improved.

[0177] In addition, the light transmittance, peel adhesion, fracture toughness, and coefficient of linear expansion α1 of the resin cured product of the present invention are measured by the method described below.

[0178] The resin cured product of the present invention can be used in a wide variety of applications where conventional epoxy resin cured products are utilized. Additionally, due to its high transparency, it can be used in applications requiring transparency. Furthermore, because it has high peel adhesion and a low coefficient of linear expansion relative to peel adhesion, it can be used as an adhesive for automotive structural bonding or as an underfill material for semiconductor chip mounting. Additionally, because it possesses excellent fracture toughness, it can be applied to aerospace materials and sports applications where it is susceptible to impact.

[0179] [Example]

[0180] The present invention will be described in detail below based on embodiments, but the present invention is not limited to these embodiments.

[0181] In addition, the meaning of the abbreviation is as follows.

[0182] BTEE: Ethyl=2-methyl-2-n-butyltellanyl-propionate

[0183] DBDT: Dibutylditelluride

[0184] AIBN: 2,2'-Azobis(isobutyronitrile)

[0185] THFMA: Tetrahydrofurfuryl methacrylate

[0186] IBMA: Isobutyl methacrylate

[0187] MMA: Methyl methacrylate

[0188] LMA: Dodecyl methacrylate

[0189] [Evaluation Method]

[0190] (Polymerization rate)

[0191] Using a nuclear magnetic resonance (NMR) measuring device (manufactured by Bruker Biospin, model name: AVANCE500 (frequency 500 MHz)), 1H-NMR was measured (solvent: deuterated chloroform (CDCl3), internal standard: tetramethylsilane (TMS)). For the obtained NMR spectrum, the integration ratio of the peaks of the vinyl group from the monomer and the ester side chain from the polymer was determined, and the polymerization rate of the monomer was calculated.

[0192] (Weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn))

[0193] High-speed liquid chromatography (manufactured by Tosho Co., model name: HLC-8320GPC) was used, and the results were obtained by gel permeation chromatography (GPC). Two TSKgel SuperMultipore HZ-H columns (Φ4.6mm × 150mm) (manufactured by Tosho Co.) were used, tetrahydrofuran was used as the mobile phase, and a differential refractive index detector was used as the detector. The measurement conditions were set as follows: column temperature at 40℃, sample concentration at 5mg / mL, sample injection volume at 10μL, and flow rate at 0.35mL / min. A calibration curve was constructed using polystyrene (molecular weights 2,890,000, 1,090,000, 706,000, 427,000, 190,000, 96,400, 37,900, 10,200, 2,630, 440) as a standard material, and the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were measured. From these measurements, the molecular weight distribution (Mw / Mn) was calculated.

[0194] (Viscosity of epoxy resin composition)

[0195] The viscosity of the epoxy resin composition (before curing) was measured at room temperature (25°C) using an E-type viscometer (product name: TVE-22L, manufactured by Toki Sangyo Co., Ltd.). A cone rotor suited to the measurement viscosity was used (1°34'×24 for less than 1500 mPa·s, 3°×R14 for 1500 mPa·s or more), the rotor rotation speed was set to 5 rpm, and the measurement range was set to 5.

[0196] (Transparency of the cured product of the epoxy resin composition)

[0197] For the cured product obtained by heating and curing the epoxy resin composition at 120°C for 90 minutes, the light transmittance of 600 nm per 6 mm was measured using a spectrophotometer U-3900 (manufactured by Hitachi High-Tech Science Co., Ltd.). The measurement was performed 10 times, and the average value of the 10 measurements was taken as the light transmittance value. The light transmittance of the cured product of each epoxy resin composition in Tables 3 and 5 is an indexed value with the light transmittance of the cured product of epoxy resin composition No. 13, which did not contain a block copolymer, set to 100%. The light transmittance of the cured products of epoxy resin compositions No. 14 and 15 in Table 4 is an indexed value with the light transmittance of the cured product of epoxy resin composition No. 16, which did not contain a block copolymer, set to 100%. The light transmittance of the cured products of epoxy resin compositions No. 17 and 18 in Table 4 is an indexed value with the light transmittance of the cured product of epoxy resin composition No. 19, which did not contain a block copolymer, set to 100%. The higher the indexed value, the better the transparency of the cured product of the epoxy resin composition. If the light transmittance is less than 2%, it is referred to as "cloudy."

[0198] (Peel adhesion of cured epoxy resin composition: N / 25mm)

[0199] The peel adhesion test was performed in accordance with JIS K6854-3. Specifically, two aluminum plates (A1050P, 0.5mm × 25mm × 200mm) were bent 90° at the 150mm mark, and an epoxy resin composition was applied to the 150mm portion to bond them in a T-shape. A 0.2mm spacer was placed between the adhesive layers. After application, the epoxy resin composition was cured by heating at 120°C for 90 minutes. After returning to room temperature, a T-shaped peel test was performed using a Shimadzu Autograph AGS-J mechanical testing machine at a head speed of 100mm / min. The measurement was performed five times, and the average value of the five measurements was taken as the peel adhesion strength.

[0200] (Fracture toughness of cured products of epoxy resin compositions)

[0201] The epoxy resin composition was poured into a mold with dimensions of 6×12×25 mm and heat-cured at 120°C for 90 minutes. On the obtained cured product, a fracture toughness test was performed using the Autograph AGS-J mechanical testing machine manufactured by Shimadzu Corporation in accordance with ASTM D5045-93. The measurement was performed 10 times, and the average value of the 10 measurements was taken as the fracture toughness value. Fracture toughness K1c represents crack propagation resistance, and a higher value indicates higher fracture toughness.

[0202] (Tensile strength of the cured product of the epoxy resin composition)

[0203] The epoxy resin composition was poured into a mold sized for a Type 3 tensile dumbbell test specimen and heat-cured at 120°C for 90 minutes. A tensile test was performed on the obtained cured material using the Autograph AGS-J mechanical testing machine manufactured by Shimadzu Corporation in accordance with JIS K6251. The stress at fracture of the dumbbell test specimen was defined as the tensile strength. Measurements were performed 10 times, and the average value of the 10 measurements was taken as the tensile strength value.

[0204] (Coefficient of linear expansion of the cured product of the epoxy resin composition)

[0205] For a cured product obtained by heating and curing an epoxy resin composition at 120°C for 90 minutes, the temperature was increased from 30°C to 300°C at a rate of 10°C / min using a thermomechanical analysis device (manufactured by Hitachi High-Tech Science Co., Ltd.), and the slope of the tangent line at 50°C to 80°C of the obtained chart was defined as the coefficient of linear expansion α1 (ppm / °C). In addition, the coefficient of linear expansion for the peel adhesion strength was calculated from the coefficient of linear expansion α1 and the peel adhesion strength measured in the above peel adhesion strength test using the following formula.

[0206] Linear expansion coefficient for peel adhesion = Linear expansion coefficient α1 (ppm / ℃) / Peel adhesion (N / 25mm)

[0207] (Observation of the dispersion state of low-compatibility components in the cured product of the epoxy resin composition)

[0208] Cured products of epoxy resin compositions (No. 2, 10, 6) were cut to a thickness of 60 nm using a microtome (ULTROTOME (trademark) V, manufactured by LKB BROMMA). After Ru staining the low-compatibility components in the cut sections using ruthenium(VIII) oxide (0.5% aqueous solution), the dispersion state of the low-compatibility components was observed using a field emission transmission electron microscope (JEM-2100F, manufactured by Nippon Electronics Co., Ltd.) or a field emission scanning electron microscope (S-4800, manufactured by Hitachi High Technologies Co., Ltd.), and field emission transmission electron microscope images (FE-TEM images) or field emission scanning electron microscope images (FE-SEM images) were acquired.

[0209] Synthesis of Block Copolymers

[0210] (Block Copolymer No. 1)

[0211] 24.38 g of THFMA, 0.63 g of IBMA, 0.74 g of BTEE, 0.41 g of DBDT, 0.0825 g of AIBN, and 25.03 g of toluene, which had been pre-nitrogen-substituted, were injected into a 300 mL reactor equipped with a nitrogen-substituted stirrer, and the mixture was reacted at 60°C for 18.25 hours to polymerize the A1 block (first stage polymerization reaction). The polymerization rate was 97.7%.

[0212] To the reaction solution obtained from the first polymerization reaction above, 50.00 g of pre-nitrogen-substituted LMA, 0.0826 g of AIBN, and 50.01 g of toluene were added, and the reaction was carried out at 60°C for 29.25 hours to polymerize Block B (second polymerization reaction). The polymerization rate was 97.4%.

[0213] To the reaction solution obtained from the second polymerization reaction above, 24.38 g of pre-nitrogen-substituted THFMA, 0.63 g of IBMA, 0.0823 g of AIBN, and 25.12 g of toluene were added, and the reaction was carried out at 60°C for 40.00 hours to polymerize the A2 block (third polymerization reaction). The polymerization rate was 99.6%. After the reaction was finished, the reaction solution was diluted with THF (tetrahydrofuran) and poured into methanol under stirring. The precipitated polymer was pressure-filtered and dried to obtain ABA-type triblock copolymer No. 1. The Mw of block copolymer No. 1 was 46900, and the Mw / Mn ratio was 1.27.

[0214] (Block copolymer No. 2~11)

[0215] Block copolymers No. 2 to 11 were prepared in the same manner as block copolymer No. 1, except that the polymerization reaction was carried out using the raw material usage and reaction conditions shown in Table 1. Block copolymers No. 6, 8, and 10 were AB-type diblock copolymers obtained without carrying out the third stage of polymerization.

[0216] Table 1 shows the raw monomers used, organic tellurium compounds, organic ditellurium compounds, azo polymerization initiators, solvents, reaction conditions, and polymerization rates. Table 2 shows the composition, Mw, and Mw / Mn of the block copolymer. In addition, the content of each structural unit in the block copolymer was calculated from the input ratio of the monomers used in the polymerization reaction and the polymerization rate.

[0217]

[0218]

[0219] Preparation of Epoxy Resin Composition

[0220] (Epoxy resin compositions No. 1~3, 5~12)

[0221] 49.77 mass% of bisphenol A type epoxy resin (product name: jER (trademark registered) 828, epoxy equivalent 194 g / eq, weight average molecular weight 370, manufactured by Mitsubishi Chemical Corporation), 45.28 mass% of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride as a curing agent (2.0 equivalents relative to the epoxy resin), 0.47 mass% of 2-ethyl-4-methylimidazole as a curing accelerator, and the block copolymer obtained above as an epoxy resin modifier in the mass% listed in Table 3 were mixed, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin compositions No. 1 to 12.

[0222] (Epoxy resin composition No. 4)

[0223] 47.57 mass% of bisphenol A type epoxy resin (product name: jER (trademark registered) 828, epoxy equivalent 194 g / eq, weight average molecular weight 370, manufactured by Mitsubishi Chemical Corporation), 43.28 mass% of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride as a curing agent (2.0 equivalents relative to the epoxy resin), 0.45 mass% of 2-ethyl-4-methylimidazole as a curing accelerator, and the block copolymer obtained above as an epoxy resin modifier in the mass% listed in Table 3 were mixed, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin composition No. 4.

[0224] (Epoxy resin composition No. 13)

[0225] 52.23 mass% of bisphenol A type epoxy resin (product name: jER (trademark registered) 828, epoxy equivalent 194 g / eq, weight average molecular weight 370, manufactured by Mitsubishi Chemical Corporation), 47.27 mass% of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride as a curing agent (2.1 equivalents relative to the epoxy resin), and 0.49 mass% of 2-ethyl-4-methylimidazole as a curing accelerator were mixed, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin composition No. 13.

[0226] (Epoxy resin compositions No. 14~15)

[0227] 47.48 mass% of bisphenol F type epoxy resin (product name: jER (trademark registered) 807, epoxy equivalent 168 g / eq, weight average molecular weight 336, manufactured by Mitsubishi Chemical Corporation), 47.57 mass% of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride as a curing agent (2.0 equivalents relative to the epoxy resin), 0.48 mass% of 2-ethyl-4-methylimidazole as a curing accelerator, and the above-mentioned block copolymer No. 2 or No. 4 as an epoxy resin modifier were mixed in the mass% listed in Table 4, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin compositions No. 14 to 15.

[0228] (Epoxy resin composition No. 16)

[0229] 49.70 mass% of bisphenol F type epoxy resin (product name: jER (trademark registered) 807, epoxy equivalent 168 g / eq, weight average molecular weight 336, manufactured by Mitsubishi Chemical Corporation), 49.80 mass% of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride as a curing agent (2.0 equivalents relative to the epoxy resin), and 0.50 mass% of 2-ethyl-4-methylimidazole as a curing accelerator were mixed, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin composition No. 16.

[0230] (Epoxy resin compositions No. 17~18)

[0231] 75.65 mass% of bisphenol A type epoxy resin (product name: jER (trademark registered) 828, epoxy equivalent 194 g / eq, weight average molecular weight 370, manufactured by Mitsubishi Chemical Corporation), 19.87 mass% of diaminodiphenylmethane as a curing agent (1.0 equivalent relative to the epoxy resin), and the above-mentioned block copolymer No. 2 or No. 5 as an epoxy resin modifier were mixed in the mass% listed in Table 4, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin compositions No. 17 to 18.

[0232] (Epoxy resin composition No. 19)

[0233] 79.2 mass% of bisphenol A type epoxy resin (product name: jER (trademark registered) 828, epoxy equivalent 194 g / eq, weight average molecular weight 370, manufactured by Mitsubishi Chemical Corporation) and 20.8 mass% of diaminodiphenylmethane as a curing agent (1.0 equivalent relative to the epoxy resin) were mixed, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin composition No. 19.

[0234] (Epoxy resin composition No. 20)

[0235] 47.51 mass% of bisphenol A type epoxy resin (product name: jER (trademark registered) 828, epoxy equivalent 194 g / eq, weight average molecular weight 370, manufactured by Mitsubishi Chemical Corporation), 43.22 mass% of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride as a curing agent (2.0 equivalents relative to the epoxy resin), 0.45 mass% of 2-ethyl-4-methylimidazole as a curing accelerator, and the block copolymer obtained above and a reactive diluent as epoxy resin modifiers in mass% as listed in Table 5 were mixed, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin composition No. 20.

[0236] (Epoxy resin composition No. 21)

[0237] 48.36 mass% of bisphenol A type epoxy resin (product name: jER (trademark registered) 828, epoxy equivalent 194 g / eq, weight average molecular weight 370, manufactured by Mitsubishi Chemical Corporation), 44.00 mass% of 4-methylcyclohexane-1,2-dicarboxylic acid anhydride as a curing agent (2.0 equivalents relative to the epoxy resin), 0.46 mass% of 2-ethyl-4-methylimidazole as a curing accelerator, and the block copolymer obtained above and a reactive diluent as epoxy resin modifiers in mass% as listed in Table 5 were mixed, and the mixture was stirred and degassed for 22 minutes using a stirred degasser (AR-250, manufactured by Shinki Co., Ltd.) to obtain epoxy resin composition No. 21.

[0238] The viscosity of the above epoxy resin composition and the evaluation results for the cured product obtained by curing the above epoxy resin composition are shown in Tables 3 to 5. In addition, the tensile strength of the cured product of epoxy resin composition No. 2 was 36.02 MPa, the tensile strength of the cured product of epoxy resin composition No. 8 was 36.78 MPa, and the tensile strength of the cured product of epoxy resin composition No. 13 was 36.99 MPa.

[0239]

[0240]

[0241]

[0242] From the results of Tables 3 to 5, it can be seen that even when the epoxy resin modifier of the present invention is blended in a small amount of less than 10 parts by mass per 100 parts by mass of epoxy resin and curing agent, the cured product of the obtained epoxy resin composition exhibits high transparency and excellent fracture toughness and peel adhesion. In addition, since fracture toughness and peel adhesion can be significantly increased with a small amount of blending, the deterioration of the epoxy resin's function, such as tensile strength, which accompanies the addition of a large amount of epoxy resin modifier can be suppressed.

[0243] In addition, the results of observing the dispersion state of the low-compatibility component in the cured products of the epoxy resin compositions (No. 2, 10, 6) using an electron microscope are shown in Figures 1 to 3.

[0244] Figure 1 shows a field emission transmission electron microscope (FE-TEM) image of the cured product of epoxy resin composition No. 2 (the black part is the low-compatibility component). As shown in Figure 1, the low-compatibility component of the cured product of epoxy resin composition No. 2 is dispersed in a string-like shape with a width (diameter) of about 10 nm and a length of about 100 nm to 500 nm. Since the width is small, about 10 nm, cavitation is likely to occur during crack extension in the cured product, and since the volume is large, stress relief is thought to be possible over a large area.

[0245] Figure 2 shows the FE-TEM phase of the cured product of epoxy resin composition No. 10 (the black part is the low-compatibility component). As shown in Figure 2, in the cured product of epoxy resin composition No. 10, some of the low-compatibility components are in the form of strings, but most are dispersed in the form of spheres with a diameter of about 10 nm. Therefore, it is thought that the stress-relaxable region is small.

[0246] Figure 3 shows an electrolytic emission scanning electron microscope (FE-SEM) image of the cured product of epoxy resin composition No. 6 (the white part is the low-compatibility component). As shown in Figure 3, the cured product of epoxy resin composition No. 6 has the low-compatibility component dispersed in a macroscopic size while accepting the epoxy resin matrix. Therefore, it is thought that cavitation is unlikely to occur in the cured product during crack extension. Industrial applicability

[0247] The epoxy resin modifier of the present invention is used by incorporating it into an epoxy resin. By incorporating the epoxy resin modifier of the present invention into an epoxy resin, the fracture toughness and peel adhesion of the epoxy resin can be increased while maintaining the high transparency of the epoxy resin. An epoxy resin composition containing the epoxy resin modifier of the present invention can be used in a wide variety of applications where conventional epoxy resins are used. Furthermore, due to its high transparency, it can also be used in applications where transparency is required. Additionally, because of its high peel adhesion, it can be used as an adhesive for automotive structural bonding or as an underfill material for semiconductor chip mounting. Moreover, because it possesses excellent fracture toughness values, it can also be applied to aerospace materials or sports applications that are susceptible to impact.

[0248] Preferred embodiment 1 of the present invention is an epoxy resin modifier containing a block copolymer, wherein the block copolymer is an ABA-type triblock copolymer having a structural unit (a-1) represented by the following general formula (1) and a structural unit (a-2) derived from a (meth)acrylate having a chain alkyl group, and a structural unit (b) derived from at least one vinyl monomer selected from the group consisting of a (meth)acrylate having a chain alkyl group and a (meth)acrylate having a cyclic alkyl group.

[0249] The content of the structural unit (a-1) represented by the above general formula (1) in each A block is 85 mass% or more and less than 100 mass% in 100 mass% of the A block, and the content of the structural unit (a-2) derived from the (meth)acrylate having the above chain alkyl group is greater than 0 mass% and less than or equal to 15 mass% in 100 mass% of the A block.

[0250]

[0251] [In general formula (1), R 1 It is a hydrogen atom or a methyl group. 0≤n≤10, Q is a cyclic ether group of 4 to 6 members or a cyclic thioether group.]

[0252] A preferred embodiment 2 of the present invention is an epoxy resin modifier described in embodiment 1, wherein the structural unit (a-2) of the A block is a structural unit derived from a (meth)acrylate having a branched chain alkyl group.

[0253] A preferred embodiment 3 of the present invention is an epoxy resin modifier described in embodiment 1 or 2, wherein the structural unit (a-1) of the A block is derived from at least one of the group consisting of tetrahydrofurfuryl (meth)acrylate, morpholino(meth)acrylate, morpholinoethyl (meth)acrylate, (3-ethyloxetane-3-yl)methyl(meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methyl(meth)acrylate, cyclic trimethylolpropaneformal(meth)acrylate, 2-[(2-tetrahydropyranyl)oxy]ethyl(meth)acrylate, and 1,3-dioxane-(meth)acrylate.

[0254] Preferred embodiment 4 of the present invention is an epoxy resin modifier described in any one of embodiments 1 to 3, wherein, among the two A blocks constituting the block copolymer, the A block with a high content of structural unit (a-1) is designated as the A1 block and the A block with a low content of structural unit (a-1) is designated as the A2 block, and the mass ratio of the A1 block to the A2 block (A1 block / A2 block) is 0.8 to 1.2.

[0255] Preferred embodiment 5 of the present invention is an epoxy resin modifier described in any one of embodiments 1 to 4, wherein the content of the A block is 30% to 70% in the total 100% mass of the block copolymer.

[0256] Preferred embodiment 6 of the present invention is an epoxy resin modifier described in any one of embodiments 1 to 5, wherein the structural unit (b) of the B block is a structural unit derived from a (meth)acrylate having a chain alkyl group having 11 to 20 carbon atoms.

[0257] Preferred embodiment 7 of the present invention is an epoxy resin modifier described in any one of embodiments 1 to 6, wherein the content of structural unit (b) of the B block is 80 mass% or more and 100 mass% or less in 100 mass% of the B block.

[0258] Preferred embodiment 8 of the present invention is an epoxy resin modifier described in any one of embodiments 1 to 7, wherein the content of the B block is 30% to 70% of the total 100% of the block copolymer.

[0259] Preferred embodiment 9 of the present invention is an epoxy resin modifier described in any one of embodiments 1 to 8, wherein the weight average molecular weight (Mw) of the block copolymer is 10,000 or more and less than 200,000.

[0260] A preferred embodiment 10 of the present invention is an epoxy resin modifier described in any one of claims 1 to 9, wherein the molecular weight distribution (Mw / Mn) of the block copolymer is 2.0 or less.

[0261] A preferred embodiment 11 of the present invention is an epoxy resin modifier described in any one of embodiments 1 to 10, wherein the block copolymer is polymerized by living radical polymerization.

[0262] A preferred embodiment 12 of the present invention is an epoxy resin composition comprising an epoxy resin, a curing agent, and an epoxy resin modifier described in any one of embodiments 1 to 11.

[0263] A preferred embodiment 13 of the present invention is an epoxy resin composition described in embodiment 12, wherein the content of the epoxy resin modifier is 1 to 25 parts by mass relative to 100 parts by mass of the total amount of the epoxy resin and the curing agent, in terms of the converted amount of the ABA-type triblock copolymer.

[0264] A preferred embodiment 14 of the present invention is an adhesive made of an epoxy resin composition described in embodiment 12 or 13.

[0265] A preferred embodiment 15 of the present invention is an underfill material made of an epoxy resin composition described in embodiment 12 or 13.

[0266] A preferred embodiment 16 of the present invention is a resin-cured product formed by curing the epoxy resin composition described in embodiment 12 or 13.

Claims

Claim 1 An epoxy resin modifier containing a block copolymer, wherein the block copolymer is an ABA-type triblock copolymer having a block A having a structural unit (a-1) represented by the following general formula (1) and a structural unit (a-2) derived from a (meth)acrylate having a chain alkyl group, and a block B having a structural unit (b) derived from at least one vinyl monomer selected from the group consisting of a (meth)acrylate having a chain alkyl group and a (meth)acrylate having a cyclic alkyl group, wherein the content of the structural unit (a-1) represented by the general formula (1) in each block A is 85 mass% or more and less than 100 mass% in 100 mass% of block A, and the content of the structural unit (a-2) derived from the (meth)acrylate having a chain alkyl group is greater than 0 mass% and less than 15 mass% in 100 mass% of block A. Epoxy resin modifier. [In general formula (1), R 1 It is a hydrogen atom or a methyl group. 0≤n≤10, Q is a cyclic ether group of 4 to 6 members or a cyclic thioether group.] Claim 2 An epoxy resin modifier according to claim 1, wherein the structural unit (a-2) of the A block is a structural unit derived from a (meth)acrylate having a branched chain alkyl group. Claim 3 An epoxy resin modifier according to claim 1, wherein the structural unit (a-1) of the block A is a structural unit derived from at least one selected from the group consisting of tetrahydrofurfuryl (meth)acrylate, morpholino(meth)acrylate, morpholinoethyl (meth)acrylate, (3-ethyloxetane-3-yl)methyl(meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methyl(meth)acrylate, cyclic trimethylolpropaneformal(meth)acrylate, 2-[(2-tetrahydropyranyl)oxy]ethyl(meth)acrylate, and 1,3-dioxane-(meth)acrylate. Claim 4 An epoxy resin modifier according to claim 1, wherein among the two A blocks constituting the block copolymer, the A block with a high content of structural unit (a-1) is designated as the A1 block and the A block with a low content of structural unit (a-1) is designated as the A2 block, and the mass ratio of the A1 block to the A2 block (A1 block / A2 block) is 0.8 to 1.

2. Claim 5 An epoxy resin modifier according to claim 1, wherein the content of block A is 30% to 70% of the total 100% of the block copolymer. Claim 6 An epoxy resin modifier according to claim 1, wherein the structural unit (b) of the B block is a structural unit derived from a (meth)acrylate having a chain alkyl group having 11 to 20 carbon atoms. Claim 7 An epoxy resin modifier according to claim 1, wherein the content of the structural unit (b) of the B block is 80 mass% or more and 100 mass% or less in 100 mass% of the B block. Claim 8 An epoxy resin modifier according to claim 1, wherein the content of the B block is 30% to 70% of the total 100% of the block copolymer. Claim 9 An epoxy resin modifier according to claim 1, wherein the weight average molecular weight (Mw) of the block copolymer is 10,000 or more and less than 200,000. Claim 10 An epoxy resin modifier according to claim 1, wherein the molecular weight distribution (Mw / Mn) of the block copolymer is 2.0 or less. Claim 11 An epoxy resin modifier according to claim 1, wherein the block copolymer is polymerized by living radical polymerization. Claim 12 An epoxy resin composition comprising an epoxy resin, a curing agent, and an epoxy resin modifier described in any one of claims 1 to 11. Claim 13 An epoxy resin composition according to claim 12, wherein the content of the epoxy resin modifier is 1 to 25 parts by mass with respect to 100 parts by mass of the total amount of epoxy resin and curing agent, in terms of the converted amount of the ABA-type triblock copolymer. Claim 14 An adhesive comprising the epoxy resin composition described in claim 12. Claim 15 An underfill material comprising the epoxy resin composition described in claim 12. Claim 16 A resin-cured product formed by curing the epoxy resin composition described in claim 12.

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