JP5096272B2 - Phenolic curing agent and epoxy resin composition using the phenolic curing agent - Google Patents

Description

  The present invention relates to a phenolic curing agent, and more particularly to a novel phenolic curing agent used as a curing agent for an epoxy resin and an epoxy resin composition using the same. The obtained epoxy resin composition can be used for various applications such as a resin composition for electronic materials and a coating agent.

  Various curing agents are used for curing the epoxy resin composition, but it is known that the performance of the cured product varies greatly depending on the type of the curing agent, and the curing agent is properly used depending on the use of the epoxy resin composition. It has been. Among these, phenolic curing agents are excellent in balance of physical properties such as adhesiveness, water resistance, and electrical performance, and are widely used as curing agents for epoxy resins in the electric / electronic field.

  Among the above-mentioned phenolic curing agents, polyvinylphenol is known to be particularly excellent in electric resistance characteristics, and various uses are being studied as a resin composition for electronic materials (for example, Patent Documents 1 and 2). Such). However, circuits installed in precision equipment such as electronic equipment and communication equipment have been increasingly faster and more dense in recent years, and have higher performance than epoxy resin compositions containing polyvinylphenol as a curing agent. It has come to be required.

  For example, warpage of a semiconductor package or a semiconductor element occurs due to a difference in coefficient of thermal expansion between the constituent members, and thus it is desired to lower the curing temperature. However, since polyvinyl phenol has a high glass transition temperature, a certain high temperature is required to reach a viscosity that sufficiently follows the adherend surface in the molten state until curing, and adhesiveness is insufficient for curing at low temperatures. Therefore, the curing temperature could not be lowered.

  Moreover, in order to absorb and relieve the stress caused by the difference in thermal expansion coefficient, it is desired to have a low elastic modulus while maintaining the hardness and heat resistance of the cured product. In the composition, the elastic modulus of the cured product was increased due to the three-dimensional crosslinking at the time of thermosetting, and the strain based on the difference in the coefficient of thermal expansion of each constituent member could not be absorbed.

  On the other hand, in order to increase the fluidity at low temperature and lower the curing temperature, it is necessary to add a thermoplastic component having a low glass transition temperature to the epoxy resin composition or improve the fluidity by adding a component having a low molecular weight. There is. In addition, as a method for absorbing a strain based on a difference in thermal expansion coefficient of each constituent member and improving thermal stress relaxation characteristics, a method of adding a rubber component to an epoxy resin composition is known. However, adding a thermoplastic or rubber component having a low glass transition temperature to the epoxy resin composition can improve the fluidity and thermal stress relaxation properties, but the heat resistance is decreased and the linear expansion coefficient is increased. In addition, there is a problem that compatibility with other components is lowered and phase separation may occur without uniform mixing.

  On the other hand, Patent Document 3 includes a vinylphenol unit and a repeating unit derived from a monomer that gives a polymer having a glass transition temperature of 0 ° C. or lower, such as (meth) acrylic acid ester, 1,3-butadiene, or isoprene. It has been shown that a thermosetting resin composition blended with a copolymer having a cured product excellent in insulating properties, heat resistance and thermal shock resistance. However, a polymer containing a (meth) acrylate unit has a problem that the effect of improving thermal stress relaxation is not large, and conversely, there is a problem that water resistance and electrical characteristics are deteriorated, and a repeating unit such as 1,3-butadiene is used. However, the copolymer containing the compound improves the thermal stress relaxation, but has a problem that the compatibility and the substrate adhesion deteriorate.

  Furthermore, in the case of a liquid epoxy resin composition used for a semiconductor package encapsulant, in order to prevent cracking, warping, and peeling, by adding a large amount of inorganic filler, the linear expansion coefficient of the cured epoxy resin can be increased. It is performed to reduce the curing shrinkage rate. In the case of a conductive adhesive, a die bonding paste, and an anisotropic conductive paste, it is necessary to add a large amount of a conductive filler to the epoxy resin in order to impart conductivity. In order to mix such an inorganic filler or a conductive filler in a large amount with an epoxy resin composition, it is necessary to use a low-viscosity resin binder. However, since polyvinylphenol is generally provided as a solid, when used in a liquid or paste form, the viscosity becomes high, and there is a problem that coating property and filling property by pouring are poor.

As a method for reducing the viscosity of the epoxy resin composition, for example, a method for adjusting the viscosity of the epoxy resin composition by dissolving in a solvent is known. However, if a large amount of solvent is used, in applications such as conductive paste, voids are generated in the cured product as traces of the solvent during curing and heating, resulting in a decrease in adhesive strength, thermal conductivity and conductivity. This is not preferable. There is also a problem that the working environment deteriorates due to evaporation of the solvent. Furthermore, although a method using a reactive diluent as a solvent is also known (for example, Patent Document 4), volume shrinkage occurs at the time of curing, and it is considered that a large amount is not preferable. .
JP 10-008006 A JP 2002-335079 A JP 2001-247656 A JP 2003-26766 A

  Therefore, the object of the present invention is to have fluidity even at a lower temperature than conventional epoxy resin compositions containing polyvinylphenol, to be cured at a low temperature, and to impair the heat resistance of the resulting cured product. And providing a novel epoxy resin composition capable of improving the thermal stress relaxation characteristics. Another object of the present invention is to provide a low-viscosity epoxy resin composition having good coating properties and filling properties with no solvent or in a smaller amount of solvent.

  As a result of intensive studies to solve this problem, the present inventors have found that the above problem can be solved by using a copolymer of a specific vinylphenol and vinyl ether as a phenolic curing agent, thereby completing the present invention. I let you.

（式中、Ｒ_１は水素原子または炭素数１〜４のアルキル基を表し、ｎは１または２を表
す）
で示されるビニルフェノール単位（ａ）と、式（２）

[式中、Ｒ_２は炭素数１〜６の直鎖または分岐鎖のアルキル基、炭素数１〜６の直鎖ま
たは分岐鎖のフルオロアルキル基、炭素数２〜６のアルコキシアルキル基、炭素数５
〜１０のシクロアルキル基または次の基

（ここで、ｍは０、１、２または３であり、Ｘは未置換または一つ若しくはそれ以上
の炭素数１〜４の直鎖または分岐鎖のアルキル基、炭素数１〜４の直鎖または分岐
鎖のフルオロアルキル基、炭素数１〜４のアルコキシ基またはハロゲン原子によっ
て置換されたフェニル基である）
で表されるアリール基またはアリールアルキル基を表す]
で表されるビニルエーテル単位（ｂ）を含み、１分子中にフェノール性水酸基を２以上有する共重合体であることを特徴とするフェノール系硬化剤である。 That is, this invention is a phenol type hardening | curing agent used as a hardening | curing agent of an epoxy resin, Comprising: Formula (1)

(Wherein R ₁ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents 1 or 2)
A vinylphenol unit (a) represented by formula (2)

[Wherein R ₂ represents a linear or branched alkyl group having 1 to 6 carbon atoms, a linear or branched fluoroalkyl group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, Carbon number 5
To 10 cycloalkyl groups or

(Where m is 0, 1, 2 or 3; X is unsubstituted or one or more straight or branched alkyl groups having 1 to 4 carbon atoms or straight chain having 1 to 4 carbon atoms; Or a branched-chain fluoroalkyl group, an alkoxy group having 1 to 4 carbon atoms, or a phenyl group substituted by a halogen atom)
Represents an aryl group or an arylalkyl group represented by
A phenolic curing agent comprising a vinyl ether unit (b) represented by the formula (1) and a copolymer having two or more phenolic hydroxyl groups in one molecule.

  Moreover, this invention is an epoxy resin composition containing the said phenol type hardening | curing agent and an epoxy resin.

  By blending the phenolic curing agent of the present invention with an epoxy resin, it has fluidity even at a lower temperature than conventional epoxy resin compositions containing polyvinylphenol, and can be cured at a low temperature. An epoxy resin composition capable of providing a cured product having excellent stress relaxation properties without impairing the heat resistance of the cured product can be obtained. And this epoxy resin composition turns into a low-viscosity epoxy resin composition which has favorable applicability | paintability and filling property with no solvent or less solvent amount.

  Therefore, the epoxy resin composition which mix | blended the phenol type hardening | curing agent of this invention can be used conveniently as a resin composition for electronic materials, for example. Specifically, a resin composition for a prepreg for a printed circuit board, a resin composition for a copper-clad laminate for a printed circuit board, a coating agent for an interlayer insulating material of a build-up printed circuit board, a resin composition for an interlayer insulating film of a semiconductor, an electronic component Resin composition for encapsulant, resin composition for encapsulant for semiconductor chip, cured resin for underfill, resist ink, conductive paste, resin composition for molded article for storing electronic parts and anisotropic conductive film It can be used for various applications such as compositions.

  Furthermore, the epoxy resin composition of this invention is excellent in hardness and adhesiveness, and can be used for various uses, such as a coating agent composition and an adhesive agent.

  The phenolic curing agent of the present invention comprises a vinylphenol unit (a) represented by the above general formula (1) and a vinyl ether unit (b) represented by the above general formula (2), and is phenolic in one molecule. It is a copolymer having two or more hydroxyl groups.

In the general formula (1), the alkyl group having 1 to 4 carbon atoms represented by R ₁ includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. And isobutyl group.

In the definition of R ₂ in the general formula (2), the linear or branched alkyl group having 1 to 6 carbon atoms includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, sec- Examples thereof include a butyl group, a tert-butyl group, an isobutyl group, an n-amyl group, and an isoamyl group. Further, the linear or branched fluoroalkyl group having 1 to 6 carbon atoms is a fluoroalkyl in which all or part of the above-mentioned linear or branched alkyl group having 1 to 6 carbon atoms is substituted with fluorine. Examples thereof include trifluoromethyl group, pentafluoroethyl group, 2,2,2-trifluoroethyl group, and the like.

Furthermore, examples of the alkoxyalkyl group having 2 to 6 carbon atoms include methoxy group methyl group, ethoxymethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 2-tetrahydropyranyl group, 2-tetrahydrofuranyl group and the like. The cycloalkyl group having 5 to 10 carbon atoms includes a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a bicyclo [2.2.1] heptyl group, a bicyclo [2.2.2] octyl group, and a tricyclo group. [5.2.1.0 ^2,6 ] decanyl group, adamantyl group and the like can be mentioned.

  On the other hand, among the groups represented by the group (3), examples of the aryl group include phenyl group, methylphenyl group, ethylphenyl group, methoxyphenyl group, ethoxyphenyl group, fluorophenyl group, and trifluoromethylphenyl group. Examples of the arylalkyl group include benzyl group, methylbenzyl group, ethylbenzyl group, methoxybenzyl group, ethoxybenzyl group, fluorobenzyl group, trifluoromethylbenzyl group and the like.

  Such a copolymer includes a vinylphenol monomer capable of deriving the vinylphenol unit (a) represented by the general formula (1) or a monomer protecting the hydroxyl group thereof, and the general formula (2). It is obtained by copolymerizing a vinyl ether monomer capable of deriving the vinyl ether unit (b) represented by

  Examples of the vinylphenol monomer capable of deriving the vinylphenol unit (a) include p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, p-isopropenylphenol, m-isopropenylphenol, o- Examples include isopropenylphenol. Of these, p-hydroxystyrene, m-hydroxystyrene, p-isopropenylphenol, and m-isopropenylphenol are preferably used.

  Examples of monomers that protect these hydroxyl groups include p-methoxystyrene, m-methoxystyrene, p-ethoxystyrene, m-ethoxystyrene, p-propoxystyrene, m-propoxystyrene, and p-isopropoxy. Alkoxy such as styrene, m-isopropoxystyrene, pn-butoxystyrene, mn-butoxystyrene, p-isobutoxystyrene, m-isobutoxystyrene, p-tert-butoxystyrene, m-tert-butoxystyrene Styrenes; p-methoxymethoxystyrene, m-methoxymethoxystyrene, p- (1-ethoxyethoxy) styrene, m- (1-ethoxyethoxy) sistyrene, p- (2-tetrahydropyranyl) oxystyrene, m- (2 -Tetrahydropyranyl) oxystyrene Alkoxyalkyloxystyrenes such as p-acetoxystyrene, m-acetoxystyrene, p-tert-butylcarbonyloxystyrene, alkanoyloxystyrenes such as m-tert-butylcarbonyloxystyrene; p-methoxycarbonyloxystyrene, m Alkoxycarbonyloxystyrenes such as -methoxycarbonyloxystyrene, p-tert-butoxycarbonyloxystyrene, m-tert-butoxycarbonyloxystyrene; p-tert-butoxycarbonylmethyloxystyrene, m-tert-butoxycarbonyloxymethylstyrene Alkoxycarbonylalkyloxystyrenes such as p-trimethylsilyloxystyrene, m-trimethylsilyloxystyrene, p-tert Butyldimethylsilyloxy styrene, alkylsilyloxy styrenes such as m-tert-butyldimethylsilyloxy styrene. Among these, p-tert-butoxystyrene, m-tert-butoxystyrene, p-acetoxystyrene, m-acetoxystyrene and the like are preferably used.

On the other hand, examples of the vinyl ether monomer capable of deriving the vinyl ether unit (b) include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, sec-butyl vinyl ether, tert-butyl vinyl ether, isobutyl vinyl ether. Alkyl vinyl ethers such as n-amyl vinyl ether and isoamyl vinyl ether; fluoroalkyl vinyl ethers such as trifluoromethyl vinyl ether, pentafluoroethyl vinyl ether and 2,2,2-trifluoroethyl vinyl ether; 2-methoxyethyl vinyl ether and 2-ethoxy Ethyl vinyl ether, 2-tetrahydropyranyl vinyl ether, 2-tetrahydrofuranyl vinyl ether Alkoxypentyl vinyl ethers such as cyclopentyl vinyl ether, cyclohexyl vinyl ether, cycloheptyl vinyl ether, cyclooctyl vinyl ether, 2-bicyclo [2.2.1] heptyl vinyl ether, 2-bicyclo [2.2.2] octyl vinyl ether, 8-tricyclo [5.2.1.0 ^2.6 ] cycloalkyl vinyl ethers such as decanyl vinyl ether, 1-adamantyl vinyl ether, 2-adamantyl vinyl ether; phenyl vinyl ether, 4-methylphenyl vinyl ether, 4-trifluoromethylphenyl vinyl ether, 4 -Aryl vinyl ethers such as fluorophenyl vinyl ether; arylalkyl vinyl ethers such as benzyl vinyl ether and 4-fluorobenzyl vinyl ether Ethers, and the like. Of these, lower alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, sec-butyl vinyl ether, tert-butyl vinyl ether, isobutyl vinyl ether, n-amyl vinyl ether, and isoamyl vinyl ether are preferably used. be able to.

  These vinylphenol monomers, monomers protecting the hydroxyl groups, and vinyl ether monomers may be used alone or in combination of two or more.

  In the copolymer constituting the phenolic curing agent of the present invention, the repeating unit (a) and the repeating unit (b) each form a block in order to effectively express the properties of the resulting cured product. In particular, it is preferable to form an ABA type triblock having the vinylphenol unit (a) as the A segment and the vinyl ether unit (b) as the B segment.

  In order to reduce the viscosity, the composition ratio (molar ratio) of the repeating unit (a) and the repeating unit (b) contained in the copolymer is preferably 1/99 to 10/90. It is more preferably 97 to 7/93, and the viscosity at 50 ° C. of the copolymer is preferably 100,000 mPa · s or less, and more preferably 60000 mPa · s or less.

  Although the polymerization method for producing the copolymer of the present invention is not particularly limited, for example, radical polymerization, (living) cationic polymerization, etc. can be mentioned, and control of the molecular structure and composition ratio of the obtained copolymer is considered. Then, living cationic polymerization is preferable.

  For example, the most preferred embodiment of the present invention, an ABA type triblock copolymer having a vinylphenol unit (a) as an A segment and a vinyl ether unit (b) as a B segment, includes a bifunctional initiator, a Lewis acid, and The above vinyl ether monomer is subjected to living cationic polymerization in the presence of a solvent, and then the above vinyl phenol monomer or a monomer protecting its hydroxyl group is added to carry out living cationic polymerization. It can be obtained by performing processing.

（式中、Ｒ_４は炭素数１〜１０のアルキレン基を表し、Ｒ_５は水素原子または炭素数１
〜４のアルキル基を表す）
で表される構造を有するものを用いることができる。 As the bifunctional initiator used in the above, the following formula (4)

(In the formula, R ₄ represents an alkylene group having 1 to 10 carbon atoms, and R ₅ represents a hydrogen atom or 1 carbon atom.
Represents an alkyl group of ~ 4)
What has the structure represented by these can be used.

Specific examples of the alkylene group having 1 to 10 carbon atoms represented by R ₄ in the above formula (4) include methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, hepta Examples include methylene group, octamethylene group, nonamethylene group, decamethylene group, cyclohexylene group and the like. Specific examples of the alkyl group having 1 to 4 carbon atoms in the definition of R ⁵ include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and an isobutyl group. Etc.

  Specific examples of the compound represented by the formula (4) include 1,1-bis (1-acetoxymethoxy) methane, 1,2-bis (1-acetoxymethoxy) ethane, 1,3-bis (1 -Acetoxymethoxy) propane, 1,4-bis (1-acetoxymethoxy) ethane, 1,2-bis (1-acetoxymethoxy) butane, 1,5-bis (1-acetoxymethoxy) ethane, 1,2-bis (1-acetoxymethoxy) pentane, 1,6-bis (1-acetoxymethoxy) hexane, 1,7-bis (1-acetoxymethoxy) heptane, 1,8-bis (1-acetoxymethoxy) octane, 1,9 -Bis (1-acetoxymethoxy) nonane, 1,10-bis (1-acetoxymethoxy) decane, 1,1-bis (1-acetoxyethoxy) methane, 1,2-bis (1-acetoxy) Toxi) ethane, 1,3-bis (1-acetoxyethoxy) propane, 1,4-bis (1-acetoxyethoxy) butane, 1,5-bis (1-acetoxyethoxy) pentane, 1,6-bis (1 -Acetoxyethoxy) hexane, 1,7-bis (1-acetoxyethoxy) heptane, 1,8-bis (1-acetoxyethoxy) octane, 1,9-bis (1-acetoxyethoxy) nonane, 1,10-bis (1-acetoxyethoxy) decane, 1,4-bis (1-acetoxymethoxy) cyclohexane, 1,4-bis (1-acetoxyethoxy) cyclohexane and the like. Of these, 1,4-bis (1-acetoxyethoxy) butane, 1,4-bis (1-acetoxyethoxy) cyclohexane and the like are preferably used. These compounds can be obtained by adding acetic acid to 1,4-butanediol divinyl ether or 1,4-cyclohexanediol divinyl ether.

  There is no restriction | limiting in particular in the addition amount of a bifunctional initiator in manufacture of the said ABA type | mold triblock copolymer, It determines suitably with the molecular weight of the target copolymer.

In addition, as the Lewis acid used in the production of the ABA type triblock copolymer, a Lewis acid generally used for cationic polymerization of vinyl ether monomers can be used without particular limitation. Specifically, for example, organometallic halides such as Et _1.5 AlCl _1.5 , TiCl ₄ , TiBr ₄ , BCl ₃ , BF ₃ , BF ₃ .OEt ₂ , SnCl ₂ , SnCl ₄ , SbCl ₅ , SbF ₅ , WCl ₆ , TaCl ₅ , VCl ₅ , FeCl ₃ , ZnBr ₂ , AlCl ₃ , AlBr _{3, and} other metal halides can be preferably used.

  The amount of the Lewis acid used is not particularly limited, but can be set in consideration of the polymerization characteristics or the polymerization concentration of the vinyl ether monomer used. Usually, it can be used at 0.1 to 100 mol%, preferably 1 to 50 mol%, relative to the vinyl ether monomer.

  Furthermore, as a solvent, aromatic hydrocarbon solvents such as benzene, toluene, xylene; propane, n-butane, isobutane, n-pentane, n-hexane, n-heptane, n-octane, isooctane, decane, hexadecane, isopentane Aliphatic hydrocarbon solvents such as n-hexane; Halogenated hydrocarbon solvents such as ethylene chloride, methylene chloride, carbon tetrachloride; Ethers such as tetrahydrofuran (THF), dioxane, diethyl ether, dibutyl ether, ethylene glycol diethyl ether A solvent is mentioned. Among these solvents, toluene, methylene chloride, and THF are preferably used. These solvents may be used alone or in combination of two or more.

  In the polymerization reaction of the ABA type triblock copolymer, a solvent, a vinyl ether monomer, a bifunctional initiator, and a Lewis acid are sequentially added to a reaction vessel, and a segment B containing a vinyl ether unit (b) is synthesized first. The Next, when the conversion of the vinyl ether monomer is completed, a vinyl phenol monomer (or a monomer whose hydroxyl group is protected) is added, and if necessary, a Lewis acid is further added and continued. By proceeding with the polymerization reaction, a segment A composed of (protected) vinylphenol units (a) is synthesized at both ends of the segment B composed of vinyl ether units (b).

  The polymerization conditions for the above polymerization reaction vary depending on the kind of Lewis acid, bifunctional initiator, monomer, solvent, etc. used, but the polymerization temperature is usually preferably in the range of -80 ° C to 150 ° C, and -78 ° C. A range of -80 ° C is more preferable. The polymerization time is usually in the range of 2 hours to 100 hours.

  Deprotection from the copolymer prepared as described above is carried out, for example, by reacting in a solvent in an acid catalyst such as hydrochloric acid or sulfuric acid at a reaction temperature of 50 to 150 ° C. for a reaction time of 1 to 30 hours. Can do.

  On the other hand, the epoxy resin composition of the present invention contains the above-mentioned phenolic curing agent and epoxy resin as essential components. Specific examples of the epoxy resin used include polycondensates of bisphenols, phenols (phenol, alkyl-substituted phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) and various aldehydes, phenols and various dienes. Polymers with compounds, polycondensates of phenols and aromatic dimethylol, glycidyl ether epoxy resins, alicyclic epoxy resins, glycidyl amine epoxy resins, glycidyl ester epoxys glycidylated biphenols, alcohols, etc. Resins and the like can be mentioned, and those that are generally available on the market can be appropriately used depending on the application.

  For example, a liquid epoxy resin composition that uses the epoxy resin composition of the present invention as a sealing material for semiconductor packages, a conductive adhesive, a die bonding paste, an anisotropic conductive paste, etc. It is preferable to use a resin. If it is not liquid at room temperature, a solvent is required, but the solvent causes bubbles and lowers the adhesive strength and thermal conductivity of the cured product, which is not preferable. In this specification, the epoxy resin that is liquid at room temperature is a liquid that is stable at room temperature by mixing it with a liquid epoxy resin at room temperature, even if it is solid at room temperature, for example. Including those indicating.

  Examples of the epoxy resin that is liquid at room temperature include bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol AD diglycidyl ether, naphthalenediol diglycidyl ether, and 3,4-epoxycyclohexylmethyl. -3 ', 4'-epoxycyclohexanecarboxylate, alicyclic epoxy resins such as vinylcyclohexene diepoxide, diglycidyl ether of bisphenol A ethylene oxide adduct, diglycidyl ether of bisphenol A propylene oxide adduct, cyclohexanedimethanol di Polybasic acid polyglycerides such as glycidyl ether, polyglycidyl ether of polyhydric alcohol, diglycidyl ether of hexahydrophthalic anhydride A lysidyl ester etc. can be mentioned. An epoxy resin may be used individually by 1 type, and may use 2 or more types together.

  The compounding ratio of the epoxy resin and the phenolic curing agent is not particularly limited as long as a predetermined effect can be obtained. Usually, the phenolic curing agent is 50 to 200 parts by mass with respect to 100 parts by mass of the epoxy resin. is there.

  In addition to the phenolic curing agent of the present invention, other curing agents can be used in the epoxy resin composition of the present invention as long as the performance is not impaired. As the curing agent, an amine compound, an acid anhydride compound, an amide compound, a phenol compound, or the like can be used. Specific examples of the curing agent that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, polyamide resin synthesized from linolenic acid and ethylenediamine, phthalic anhydride, triethylene anhydride. Mellitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, bisphenols, phenols (phenol, alkyl substituted) Polymerization of phenol, naphthol, alkyl-substituted naphthol, dihydroxybenzene, dihydroxynaphthalene, etc.) with various aldehydes, phenols and various diene compounds , Polycondensates of phenols with aromatic dimethylol, biphenols and modified products thereof, hydroxystyrene compound or polymers thereof and the like.

  Moreover, you may use together a hardening accelerator with the epoxy resin composition of this invention. Specific examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-ethylimidazole and 2-ethyl-4-methylimidazole; 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo ( Tertiary amines such as 5,4,0) undecene-7; phosphines such as triphenylphosphine; metal compounds such as tin octylate; As for a hardening accelerator, 0.01-15 mass parts is normally used as needed with respect to 100 mass parts of epoxy resins.

  When the epoxy resin contained in the epoxy resin of the present invention and the phenolic curing agent of the present invention are liquid at room temperature, it is not essential to use a solvent, but as necessary to adjust the viscosity, coating properties, etc. You may mix | blend a solvent. Examples of the solvent include known solvents such as alcohol solvents, ester solvents, ether solvents, ketone solvents, hydrocarbon solvents, and fatty acid solvents. Specifically, for example, toluene, xylene, tetrahydrofuran, acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-hexanone, 2-heptanone, ethyl carbitol acetate, butyl carbitol acetate, butyl carbitol, butyl cellosolve, butyl cellosolve acetate, propylene glycol Examples of the organic solvent include monomethyl ether acetate and triethylene glycol monobutyl ether, but are not limited thereto.

  Furthermore, it is possible to add various compounding agents such as fillers such as silica, alumina, talc and silver powder, silane coupling agents, mold release agents and pigments to the epoxy resin composition of the present invention. it can.

  Although the curing conditions of the epoxy resin composition of the present invention are not particularly limited, the composition is cured by heating, for example, at a temperature of 50 to 200 ° C. for about 10 minutes to 48 hours, depending on the use of the cured product. Can be made. Moreover, in order to fully advance hardening or to prevent generation | occurrence | production of a bubble, it can also heat in two steps, for example, in a 1st step, it heats at the temperature of 50-150 degreeC for about 10 minutes-10 hours, Furthermore, it can be cured by heating at a temperature of 100 to 200 ° C. for about 30 minutes to 12 hours. Practically, the curing temperature and the curing time are determined in consideration of productivity, physical properties of the obtained cured product, and the like.

  The present invention will be further described below with reference to synthesis examples, examples, comparative examples and test examples, but the present invention is not limited to these examples. The physical properties of the copolymers obtained in the synthesis examples were evaluated by the following methods.

Average copolymer composition:
^It calculated | required from the measurement result of < ¹³ > C-NMR.
Weight average molecular weight Mw and molecular weight distribution Mw / Mn:
Obtained from standard polystyrene calibration curve by gel permeation chromatography (GPC) method [RI detector; column is Shodex KF-801 + KF
-805L; eluent is tetrahydrofuran].
Viscosity measurement:
Measured with a block field rotational viscometer.

Synthesis example 1
p-isopropenylphenol / ethyl vinyl ether / p-isopropenyl
Production of phenolic triblock polymer (copolymer 1):

A glass container with a three-way stopcock was prepared, and after substituting with argon, it was heated in an argon atmosphere to remove adsorbed water in the glass container. 252.6 g of ethyl vinyl ether (hereinafter referred to as “EVE”), 280 g of ethyl acetate, 9.4 g of 1,4-bis (1-acetoxyethoxy) butane and 2640 g of toluene are placed in a container, and the system temperature is 0 ° C. Then, 68 ml of 0.91 mol (hereinafter referred to as M) / L toluene solution of Et _1.5 AlCl _1.5 was added to initiate polymerization. The conversion rate of EVE was monitored in a time-sharing manner using gas chromatography (GC). When the conversion of EVE monomer was completed, 21.2 g of p-isopropenylphenol (hereinafter referred to as “PIPP”) was added to the reaction solution. The reaction was continued further.

When 2.5 hours and 5 hours had elapsed after the addition of PIPP, ₄ ml and 2 ml of a 0.5 M / L toluene solution of SnCl ₄ were added, respectively. The reaction was completed 5.5 hours after the addition of PIPP. 100 ml of 1 M / L NH ₃ methanol solution was added to the polymerization reaction system to stop the reaction, 4% by mass of aluminum oxide was added to the reaction mixture solution, and the mixture was stirred for 24 hours to adsorb and remove the catalyst, and the pore size was 0.1 μm. Aluminum oxide was removed with a filter. The filtrate was concentrated under reduced pressure using an evaporator to obtain a PIPP / EVE / PIPP triblock polymer (copolymer 1).

  The average composition of the obtained copolymer 1 was PIPP / EVE = 4.3 / 95.7. The weight molecular weight Mw was 17,800, the number average molecular weight Mn was 13300, and the molecular weight distribution Mw / Mn was 1.34. Furthermore, the viscosity in 50 degreeC was 52400 mPa * s.

Synthesis example 2
p-isopropenylphenol / ethyl vinyl ether / p-isopropenyl
Production of phenolic triblock polymer (copolymer 2):

A glass container with a three-way stopcock was prepared, and after substituting with argon, it was heated in an argon atmosphere to remove adsorbed water in the glass container. 252.6 g of EVE, 280 g of ethyl acetate, 9.4 g of 1,4-bis (1-acetoxyethoxy) butane and 2640 g of toluene were placed in the container, and when the system temperature reached 0 ° C., Et _1.5 AlCl _1.5 Polymerization was initiated by adding 68 ml of 0.91 M / L toluene solution. The EVE conversion was monitored in a time-sharing manner using gas chromatography (GC), and 28.4 g of PIPP) was added to the reaction solution when the conversion of the EVE monomer was completed, and the reaction was continued.

When 2.5 hours had elapsed after the addition of PIPP, 14 ml of a 0.5 M / L toluene solution of SnCl ₄ was added. The reaction was terminated 6 hours after the addition of PIPP. 100 ml of 1 M / L NH ₃ methanol solution was added to the polymerization reaction system to stop the reaction, 4% by mass of aluminum oxide was added to the reaction mixture solution, and the mixture was stirred for 24 hours to adsorb and remove the catalyst, and the pore size was 0.1 μm. Aluminum oxide was removed with a filter. The filtrate was concentrated under reduced pressure using an evaporator to obtain a PIPP / EVE / PIPP triblock polymer (copolymer 2).

  The average composition of the obtained copolymer 2 was PIPP / EVE = 5.7 / 94.3. The weight molecular weight Mw was 12800, the number average molecular weight Mn was 10400, and the molecular weight distribution Mw / Mn was 1.23. Furthermore, the viscosity in 50 degreeC was 36000 mPa * s.

Example 1
100 parts by mass of bisphenol A type epoxy resin (EPICLON 850s; manufactured by DIC) as an epoxy resin and 66 parts by mass of the copolymer 1 produced in Synthesis Example 1 as a phenolic curing agent are mixed to obtain an epoxy resin composition (1a). It was.

  Next, 1 part by mass of 2-ethyl-4-methylimidazole (manufactured by Wako Pure Chemical Industries) as a curing accelerator and 70 parts by mass of tetrahydrofuran as a solvent are added to the epoxy resin composition (1a), and the epoxy resin composition is added. (1b), applied onto a SUS304 plate, and heat-treated in a dryer at 150 ° C. for 2 hours and at 180 ° C. for 5 hours to obtain a cured product.

Example 2
In Example 1, epoxy resin compositions (2a) and (2b) were obtained in the same manner as in Example 1 except that the polymer 2 produced in Synthesis Example 2 was used as the phenolic curing agent.

Comparative Example 1
In Example 1, the epoxy resin composition (3a) and the epoxy resin composition (3a) were used in the same manner as in Example 1 except that polyvinyl phenol resin (Marcarinka-S-2; manufactured by Maruzen Petrochemical Co., Ltd.) was used as the phenolic curing agent. (3b) was obtained.

Test example 1
For the epoxy resin compositions (1a), (2a) and (3a) obtained in Example 1, Example 2 and Comparative Example 1, the viscosities at 50 ° C. and 150 ° C. were measured with a block field type rotational viscometer. The results are shown in Table 1.

  As is apparent from Table 1, the epoxy resin compositions (1a) and (2a) of Examples 1 and 2 using the phenolic curing agent according to the present invention are the epoxy resin compositions of Comparative Example 1 using polyvinylphenol. Compared with (3a), the viscosity at 50 ° C. is low. When no filler is used, it can be used without a solvent, and when a filler is used, the amount of solvent can be reduced.

  In Comparative Example 1, the viscosity of the epoxy composition (3a) at 150 ° C. exceeds 300 mPa · s, whereas in the epoxy compositions (1a) and (2a) of Examples 1 and 2, it is less than 100 mPa · s. This indicates that a low viscosity that sufficiently follows the adherend surface at a lower temperature is reached even in a molten state until curing. Therefore, it is suggested that a cured product having excellent adhesion to the adherend surface can be obtained even at a lower temperature.

Test example 2
In Example 1, Example 2, and Comparative Example 1, the following characteristics were evaluated for the cured products obtained from the epoxy resin compositions (1b), (2b), and (3b), respectively. The results are shown in Table 2.

<Characteristics and measurement method>
Glass-transition temperature:
Pyris 1 DSC (input compensation type) manufactured by PerkinElmer, Inc.
Measured in min 5% weight loss temperature:
Perkin Elmer Pyris 1 TGA, measured at a heating rate of 10 ° C./min Hardness test:
Evaluated by mechanical pencil hardness test Adhesion test:
Evaluation by cross-cut tape method

  Further, as apparent from Table 2, the cured products obtained from the epoxy resin compositions (1b) and (2b) of Examples 1 and 2 have a glass transition point derived from vinyl ether units below room temperature, and vinyl ether units It is shown that the phase derived from is phase-separated finely in the cured product. Therefore, the elasticity modulus of hardened | cured material falls and the thermal stress relaxation characteristic of hardened | cured material can be improved.

  On the other hand, the change in elastic modulus at high temperature of the cured product is governed by the phase derived from the cross-linked product of the epoxy resin and the vinylphenol unit, but the epoxy resin compositions (1b) and (2b) of Examples 1 and 2 The glass transition temperature and the 5% weight loss temperature of the cured product obtained at the temperature higher than room temperature are compared with the cured product obtained from the epoxy resin composition (3b) of Comparative Example 1 using polyvinylphenol. The heat resistance is comparable or slightly lower and practically inferior in heat resistance. Moreover, it is excellent also in hardness and adhesiveness, and can be suitably used in applications such as electric / electronic fields and coating agent compositions.

Examples 3-6, Comparative Examples 2-3
Resin compositions (4b) to (9b) were prepared in the same manner as in Example 1 with the formulation shown in Table 3, and the properties of the cured products were measured. The results are shown in Table 3.

  As is apparent from Table 3, the epoxy resin composition (epoxy resin compositions (4b) and (5b)) in which the epoxy resin is changed is also an epoxy resin (epoxy resin) in which the polymer of the present invention and polyvinylphenol are used in combination. Also in the compositions (6b) and (7b), cured products almost similar to the epoxy resins (1b) and (2b) of Examples 1 and 2 were obtained.

  The epoxy resin composition containing the polyvinylphenol curing agent of the present invention has fluidity even at a low temperature and can be cured at a low temperature as compared with an epoxy resin composition containing a conventional polyvinylphenol. Moreover, this thing has favorable application | coating property and a filling property with no solvent or less solvent amount. Moreover, the cured product obtained can improve the thermal stress relaxation characteristics while having good heat resistance.

Therefore, the polyvinyl phenol-based curing agent and the epoxy resin composition containing the same according to the present invention can be advantageously used in applications such as electric / electronic fields and coating agent compositions.

Claims (5)

A phenolic curing agent used as a curing agent for an epoxy resin, which has the formula (1)

(Wherein R ₁ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents 1 or 2)
A vinylphenol unit (a) represented by formula (2)

[Wherein R ₂ represents a linear or branched alkyl group having 1 to 6 carbon atoms, a linear or branched fluoroalkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or Next group

(Where m is 0, 1, 2 or 3; X is unsubstituted or one or more straight or branched alkyl groups having 1 to 4 carbon atoms or straight chain having 1 to 4 carbon atoms; Or a branched-chain fluoroalkyl group, an alkoxy group having 1 to 4 carbon atoms, or a phenyl group substituted by a halogen atom)
Represents an aryl group or an arylalkyl group represented by
A phenolic curing agent comprising a vinyl ether unit (b) represented by the formula (2) and having two or more phenolic hydroxyl groups in one molecule.   The phenolic curing agent according to claim 1, wherein the copolymer forms an ABA type triblock having the vinylphenol unit (a) as an A segment and the vinyl ether unit (b) as a B segment.   The phenolic curing agent according to claim 1 or 2, wherein the molar composition ratio of the vinylphenol unit (a) and the vinylphenol unit (b) in the copolymer is from 1/99 to 10/90.   The phenolic curing agent according to any one of claims 1 to 3, wherein the copolymer has a viscosity of 100000 mPa · s or less at 50 ° C. The epoxy resin composition containing the phenol type hardening | curing agent and epoxy resin in any one of Claims 1-4.