JP2005029720A - Aromatic polyamide resin, epoxy resin composition, and its cured product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy composition whose cured product has flame retardancy, flexibility and heat resistance and whose varnish excels in storage stability. <P>SOLUTION: The aromatic polyamide resin for an epoxy resin curing agent has a structure represented by formula (1). In the formula m and n are each an average value; m+n is a positive number of 2-200; n is a positive number of ≥0.1; Ar<SP>1</SP>and Ar<SP>3</SP>are each an arylene group; Ar<SP>2</SP>is an arylene group having a phenolic hydroxy group; and Ar<SP>4</SP>indicates the same meaning as Ar<SP>1</SP>or Ar<SP>2</SP>. The epoxy resin composition contains the polyamide resin as the curing agent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a cured product excellent in flame retardancy and heat resistance without containing a halogen flame retardant or an antimony compound, and when formed into a film, an epoxy resin curing agent having sufficient flexibility and storage The present invention relates to an epoxy resin composition having excellent stability.

  Epoxy resins are generally cured with various curing agents, resulting in cured products with excellent mechanical properties, water resistance, chemical resistance, heat resistance, electrical properties, etc., adhesives, paints, laminates, moldings It is used in a wide range of fields such as materials and casting materials. Conventionally, the most commonly used epoxy resin includes bisphenol A type epoxy resin. As other flame retardants, tetrabromobisphenol A and its epoxidized product, or a compound obtained by reacting tetrabromobisphenol A with a bisphenol A type epoxy resin are generally known. Further, acid anhydrides and amine compounds are known as curing agents for epoxy resins, but phenol novolac is often used from the viewpoint of reliability such as heat resistance in the field of electric and electronic parts.

JP-A-8-143661

  However, it has been pointed out that a compound containing bromine as described above is excellent in flame retardancy, but may generate substances that cause environmental pollution during disposal and incineration. Similarly, antimony compounds used as flame retardant aids are also concerned about toxicity. Due to the recent increase in environmental protection awareness, there is an increasing demand for halogen-free and antimony-free epoxy resin compositions. In addition, a cured product of an epoxy resin using phenol novolac as a curing agent is excellent in reliability, but the cured product is rigid and lacks flexibility. In recent years, electrical and electronic components are not only used for conventional large packages and glass fiber-based substrates, but are also applied to polyimide, PET (polyethylene terephthalate) film, and metal foil in a varnish state, and then the solvent is removed. Sheet-like molded products have been developed. The resin used in such a case is required to have heat resistance of a cured product from the viewpoint of the reliability of electric / electronic parts. Furthermore, in the varnish-like epoxy resin composition as described above, the epoxy resin and the curing agent component react at the time of storage, and there are many cases where stability with time such as viscosity change is pointed out.

  In light of these circumstances, the present inventors have obtained a cured product excellent in flame retardancy, heat resistance, and flexibility, and have earnestly studied for an epoxy resin composition having high storage stability in varnish. It came to complete.

That is, the present invention provides (1) the following formula (1)

（式中、ｍ、ｎは平均値でありｍ＋ｎは２〜２００の正数であり、ｎは０．１以上の正数である。Ａｒ^１、Ａｒ^３は二価の芳香族基、Ａｒ^２はフェノール性水酸基を有する二価の芳香族基であり、Ａｒ^４はＡｒ^１或いはＡｒ^２と同じ意味を表す。）
で表される構造を有するエポキシ樹脂硬化剤用芳香族ポリアミド樹脂、
（２）エポキシ樹脂（成分（ａ））及び前記式（１）の硬化剤（成分（ｂ））を含有するエポキシ樹脂組成物、
（３）成分（ａ）が、ノボラック型エポキシ樹脂、キシリレン骨格含有フェノールノボラック型エポキシ樹脂、ビフェニル骨格含有ノボラック型エポキシ樹脂、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、テトラメチルビフェノール型エポキシ樹脂及びトリフェニルメタン型エポキシ樹脂からなる群から選ばれる１種以上である上記（２）記載のエポキシ樹脂組成物、
（４）成分（ａ）中のエポキシ基１当量に対して、成分（ｂ）中の水酸基当量が０．７〜１．２当量である上記（２）〜（３）のいずれか1項に記載のエポキシ樹脂組成物、
（５）硬化促進剤を含有する上記（２）〜（４）のいずれか1項に記載のエポキシ樹脂組成物、
（６）上記（２）〜（５）のいずれか１項に記載のエポキシ樹脂組成物を溶剤に溶解してなるワニス、
（７）平面状支持体の両面または片面に上記（２）〜（６）のいずれか1項に記載の組成物からなる層を有するシート、
（８）平面状支持体がポリイミドフィルムである上記（７）記載のシート、
（９）平面状支持体が金属箔である上記（７）記載のシート、
（１０）平面状支持体が剥離フィルムである上記（７）に記載のシート、
（１１）上記（６）記載のワニスを基材に含浸させ加熱乾燥して得られるプリプレグ、
（１２）上記（２）〜（５）のいずれか１項に記載のエポキシ樹脂組成物を硬化してなる硬化物
を提供するものである。

(In the formula, m and n are average values, m + n is a positive number of 2 to 200, and n is a positive number of 0.1 or more. Ar ¹ and Ar ³ are divalent aromatic groups, Ar ^2. Is a divalent aromatic group having a phenolic hydroxyl group, and Ar ⁴ represents the same meaning as Ar ¹ or Ar ^2. )
An aromatic polyamide resin for an epoxy resin curing agent having a structure represented by:
(2) an epoxy resin composition containing an epoxy resin (component (a)) and a curing agent of the formula (1) (component (b)),
(3) Component (a) is a novolak type epoxy resin, a xylylene skeleton-containing phenol novolak type epoxy resin, a biphenyl skeleton-containing novolac type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a tetramethylbiphenol type epoxy resin, and The epoxy resin composition according to the above (2), which is one or more selected from the group consisting of triphenylmethane type epoxy resins,
(4) In any one of (2) to (3) above, the hydroxyl group equivalent in component (b) is 0.7 to 1.2 equivalents relative to 1 equivalent of epoxy group in component (a). The epoxy resin composition according to the description,
(5) The epoxy resin composition according to any one of (2) to (4) above, which contains a curing accelerator,
(6) A varnish obtained by dissolving the epoxy resin composition according to any one of (2) to (5) above in a solvent,
(7) A sheet having a layer made of the composition according to any one of (2) to (6) on both sides or one side of a planar support,
(8) The sheet according to (7), wherein the planar support is a polyimide film,
(9) The sheet according to (7), wherein the planar support is a metal foil,
(10) The sheet according to (7), wherein the planar support is a release film,
(11) A prepreg obtained by impregnating a base material with the varnish described in (6) and drying by heating.
(12) A cured product obtained by curing the epoxy resin composition according to any one of (2) to (5) above is provided.

  The cured product of the epoxy resin composition of the present invention is excellent in flame retardancy, flexibility, and heat resistance, and its varnish is excellent in storage stability. Therefore, a molding material, a casting material, a laminated material, It is extremely useful for a wide range of applications such as paints and resists.

  In the present invention, the epoxy resin used as component (a) is not particularly limited as long as it has two or more epoxy groups in one molecule, but from the viewpoint of mechanical strength, flame retardancy, etc. An epoxy resin having an aromatic ring such as a biphenyl ring or a naphthalene ring is preferred. Specifically, novolak-type epoxy resin, xylylene skeleton-containing phenol novolak-type epoxy resin, biphenyl skeleton-containing novolak-type epoxy resin, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, tetramethylbiphenol-type epoxy resin, triphenylmethane-type epoxy resin Examples of the resin include, but are not limited to, resin.

  The aromatic polyamide resin (component (b)) of the present invention is an aromatic polyamide resin having a phenolic hydroxyl group in the polymer structure and represented by the formula (1). About the synthesis | combining method of the aromatic polyamide resin of Formula (1), it can manufacture by performing polycondensation with the aromatic diamine component and aromatic dicarboxylic acid component which are described in patent document 1, for example. Here, the use ratio of the aromatic diamine component and the aromatic dicarboxylic acid component is aromatic diamine component / aromatic dicarboxylic acid component = 1.5 to 1.001 (molar ratio), preferably aromatic diamine component / aromatic dicarboxylic. Acid component = 1.4 to 1.01 (molar ratio).

  The aromatic polyamide resin represented by the formula (1) of the present invention can be obtained by performing the condensation polymerization reaction in the presence of a phosphite ester and a pyridine derivative. According to the above production method, without protecting the phenolic hydroxyl group which is a functional group, and without causing a reaction between the phenolic hydroxyl group and another reactive group such as a carboxyl group or an amino group, The aromatic polyamide copolymer can be easily produced. In addition, there is an advantage that a high temperature is not required for condensation polymerization, that is, condensation polymerization is possible at about 150 ° C. or less.

  Hereinafter, the method for producing the aromatic polyamide resin of the present invention will be described in more detail. Examples of the aromatic diamine used for producing the aromatic polyamide resin include m-phenylenediamine, p-phenylenediamine, m-tolylenediamine, 4,4′-diaminodiphenyl ether, and 3,3′-dimethyl-4. , 4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl thioether, 3,3′-dimethyl-4,4′-diaminodiphenyl thioether, 3,3′-diethoxy-4,4 '-Diaminodiphenylthioether, 3,3'-diaminodiphenylthioether, 4,4'-diaminobenzophenone, 3,3'-dimethyl-4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 4,4' -Diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3, 3'-dimethoxy-4,4'-diaminodiphenyl thioether, 2,2'-bis (3-aminophenyl) propane, 2,2'-bis (4-aminophenyl) propane, 4,4'-diaminodiphenylsulfur Foxide, 4,4′-diaminodiphenylsulfone, benzidine, 3,3′-dimethylbenzidine, 3,3′-dimethoxybenzidine, 3,3′-diaminobiphenyl, p-xylylenediamine, m-xylylene Range amine, o-xylylene diamine, 2,2'-bis (3-aminophenoxyphenyl) propane, 2,2'-bis (4-aminophenoxyphenyl) propane, 1,3-bis (4-aminophenoxyphenyl) ) Benzene, 1,3′-bis (3-aminophenoxyf) propane, bis (4-amino-3-methylphenyl) methane, bis ( -Amino-3,5-dimethylphenyl) methane, bis (4-amino-3-ethylphenyl) methane, bis (4-amino-3,5-diethylphenyl) methane, bis (4-amino-3-propylphenyl) ) Methane, bis (4-amino-3,5-dipropylphenyl) methane and the like, but are not limited thereto. You may use these 1 type or in mixture of 2 or more types.

  Furthermore, as the hydroxyl group-containing aromatic dicarboxylic acid used for introducing a phenolic hydroxyl group into an aromatic polyamide resin, 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, 2-hydroxyisophthalic acid, 3-hydroxyisophthalic acid, 2-hydroxyterephthalic acid or the like can be used. However, the present invention is not limited to these.

  Examples of dicarboxylic acids used for producing an aromatic polyamide resin for an epoxy resin curing agent include phthalic acid, isophthalic acid, terephthalic acid, 4,4′-oxydibenzoic acid, 4,4′-biphenyldicarboxylic acid, 3,3′-, methylene dibenzoic acid, 4,4′-methylene dibenzoic acid, 4,4′-thiodibenzoic acid, 3,3′-carbonyl dibenzoic acid, 4,4′-carbonyl dibenzoic acid 4,4′-sulfonyldibenzoic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-naphthalenedicarboxylic acid, and the like, but are not limited thereto. It is not done. The aromatic dicarboxylic acid having a phenolic hydroxyl group is preferably contained in an amount of 5 mol% or more, more preferably 10 mol% or more based on the total carboxylic acid.

  Examples of the phosphite ester include triphenyl phosphite, diphenyl phosphite, tri-o-tolyl phosphite, di-o-tolyl phosphite, tri-m-tolyl phosphite, triphosphite -P-tolyl, di-p-tolyl phosphite, di-p-chlorophenyl phosphite, tri-p-chlorophenyl phosphite, di-p-chlorophenyl phosphite, and the like. It is not limited.

  Examples of the pyridine derivative used together with the above phosphite ester include pyridine, 2-picoline, 3-picoline, 4-picoline, 2,4-lutidine and the like.

  The condensing agent used in the method for producing the aromatic polyamide resin of the present invention is the above phosphite ester and pyridine derivative, but the pyridine derivative is generally added to an organic solvent and used as a mixed solvent. The organic solvent does not substantially react with the phosphite and has a property of dissolving the aromatic diamine compound and the dicarboxylic acid well, and is a good solvent for the aromatic polyamide resin as a reaction product. It is desirable that Typical examples of such an organic solvent are amide solvents such as N-methylpyrrolidone and dimethylacetamide. Particularly preferred is a mixed solvent comprising a pyridine derivative and N-methyl-2-pyrrolidone. Usually, a mixed solvent in which a pyridine derivative is added at 5 to 30% by weight with respect to 100% by weight of the mixed solvent is used.

  In order to obtain an aromatic polyamide resin having a high degree of polymerization, it is preferable to add inorganic salts such as lithium chloride and calcium chloride in addition to the above phosphite ester and pyridine derivative.

  Hereinafter, the method for producing the aromatic polyamide resin of the present invention will be described more specifically. First, a phosphite is added to a mixed solvent composed of an organic solvent containing a pyridine derivative, and then dicarboxylic acids and 50 to 99 mol% aromatic diamines are added to 100 mol% of the dicarboxylic acids, Subsequently, an aromatic polyamide resin can be obtained by heating and stirring under an inert atmosphere such as nitrogen. After completion of the reaction, the reaction mixture is poured into a non-solvent such as methanol and hexane to separate the purified polymer, and then purified by a reprecipitation method to remove by-products and inorganic salts. An aromatic polyamide resin can be obtained.

  In the above production method, the addition amount of the phosphite, which is a condensing agent, is usually equimolar or more with respect to the carboxyl group, but more than 30 times mol is not efficient. The amount of the pyridine derivative needs to be equimolar or more with respect to the carboxyl group, but in actuality, the pyridine derivative is often used in a large excess in the role of a reaction solvent. The amount of the mixed solvent composed of the pyridine derivative and the organic solvent is preferably in a range of 5 to 30% by weight with respect to 100% by weight of the theoretically obtained aromatic polyamide resin. The reaction temperature is usually preferably 60 to 180 ° C. The reaction time is greatly influenced by the reaction temperature, but in any case, it is preferable to stir the reaction system until the maximum viscosity representing the maximum degree of polymerization is obtained, and is usually from several minutes to 20 hours.

  The intrinsic viscosity value (measured with a 0.5 g / dl N, N-dimethylacetamide solution at 30 ° C.) of the aromatic polyamide resin having a preferable average degree of polymerization is in the range of 0.1 to 4.0 dl / g. . In general, whether or not the polymer has a preferable average degree of polymerization is determined by referring to the intrinsic viscosity. An intrinsic viscosity of less than 0.1 dl / g is not preferable because the film formability and the appearance of properties as an aromatic polyamide resin are insufficient. On the other hand, if the intrinsic viscosity is larger than 4.0 dl / g, there is a problem that the degree of polymerization is too high, the solvent solubility is deteriorated, and the moldability is deteriorated.

  In order to obtain the varnish of the present invention, the terminal ratio of the aromatic polyamide resin of the present invention is converted to a carboxylic acid by making the charging ratio of the aromatic dicarboxylic acid higher than that of the aromatic diamine.

In the epoxy resin composition of the present invention, as the curing agent, other curing agents may be used in addition to the phenolic hydroxyl group-containing aromatic polyamide resin having the structure represented by the formula (1). Specific examples of curing agents that can be used in combination include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, polyamide resin synthesized from linolenic acid and ethylenediamine, phthalic anhydride, anhydrous Trimellitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic acid anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolak, triphenylmethane and these Modified products, imidazoles, BF ₃ -amine complexes, guanidine derivatives and the like, but are not limited thereto. When these are used in combination, the proportion of the phenolic hydroxyl group-containing aromatic polyamide resin represented by the formula (1) in the total curing agent is usually 20% by weight or more, preferably 30% by weight or more.

  In the epoxy resin composition of the present invention, the amount of the curing agent used is preferably 0.7 to 1.2 active hydrogen equivalents relative to 1 equivalent of epoxy groups of the epoxy resin. When less than 0.7 active hydrogen equivalent with respect to 1 equivalent of epoxy group, or when exceeding 1.2 active hydrogen equivalent, curing may be incomplete and good cured properties may not be obtained. The hydroxyl equivalent of the aromatic polyamide resin for epoxy resin curing agent represented by formula (1) can be calculated from the ratio of aromatic diamines and aromatic dicarboxylic acids charged during the reaction.

  Moreover, when using the said hardening | curing agent, a hardening accelerator may be used together. Specific examples of the curing accelerator that can be used include, for example, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl- Imidazoles such as 5-hydroxymethylimidazole, tertiary amines such as 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo (5,4,0) undecene-7, triphenylphosphine, etc. Phosphines, and metal compounds such as tin octylate. The curing accelerator is used as necessary in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin.

  The epoxy resin composition of the present invention contains an inorganic filler as necessary. Specific examples of the inorganic filler that can be used include silica, alumina, talc and the like. The inorganic filler is used in an amount of 0 to 90% by weight in the epoxy resin composition of the present invention. Furthermore, various compounding agents such as silane coupling agents, mold release agents such as stearic acid, palmitic acid, zinc stearate, calcium stearate, and pigments can be added to the epoxy resin composition of the present invention.

  The epoxy resin composition of the present invention can be obtained by uniformly mixing the above components. The epoxy resin composition of the present invention can be easily made into a cured product by a method similar to a conventionally known method. For example, the epoxy resin, the curing agent, and if necessary, the curing accelerator, the inorganic filler, and the compounding agent are mixed sufficiently until uniform using an extruder, a kneader, a roll, or the like as necessary. By obtaining an epoxy resin composition, molding the epoxy resin composition by a melt casting method, a transfer molding method, an injection molding method, a compression molding method or the like, and further heating at 80 to 200 ° C. for 2 to 10 hours The cured product of the present invention can be obtained.

  The varnish of the present invention is obtained by dissolving the epoxy resin composition of the present invention in a solvent. Examples of the solvent used include amide solvents such as γ-butyrolactone, N-methylpyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide, N, N-dimethylimidazolidinone and the like. , Sulfones such as tetramethylene sulfone, ether solvents such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether monoacetate, propylene glycol monobutyl ether, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone And ketone solvents such as cyclohexanone and aromatic solvents such as toluene and xylene. The solid content concentration in the obtained varnish is usually 10 to 80% by weight, preferably 20 to 70% by weight.

  A sheet having a layer made of the epoxy resin composition of the present invention is obtained by drying the varnish on a planar support by various coating methods such as a gravure coating method, screen printing, metal mask method, and spin coating method known per se. It is obtained by drying after coating so that the subsequent thickness becomes a predetermined thickness, for example, 5 to 100 μm. Which coating method is used depends on the type, shape, size, and film thickness of the coating film. It is selected appropriately. Examples of the base material include various polymers such as polyamide, polyimide, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyether ether ketone, polyether imide, polyether ketone, polyketone, polyethylene, polypropylene, and / or copolymers thereof. A film made from the above, or a metal foil such as a copper foil, preferably polyimide or metal foil. Furthermore, a sheet-like cured product can be obtained by heating. A preferred use of the sheet of the present invention is a flexible printed wiring board material such as a flexible printed wiring board, a coverlay material, and a bonding sheet.

  Further, a prepreg obtained by impregnating a base material such as glass fiber, carbon fiber, polyester fiber, alumina fiber, paper, etc. with the varnish of the present invention and drying by heating can be subjected to hot press molding to obtain a cured product. The solvent used here is usually 10 to 70% by weight, preferably 15 to 70% by weight in the mixture of the epoxy resin composition of the present invention and the solvent.

  Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, parts are parts by weight unless otherwise specified.

Example 1
A flask equipped with a thermometer, condenser, and stirrer was purged with nitrogen gas, and 45.5 parts of 5-hydroxyisophthalic acid, 41.5 parts of isophthalic acid, 98 parts of 3,4'-diaminodiphenyl ether, and 3.4 parts of lithium chloride Parts, 344 parts of N-methylpyrrolidone and 115.7 parts of pyridine were dissolved with stirring, and then 251 parts of triphenyl phosphite was added and reacted at 90 ° C. for 4 hours to obtain a phenolic hydroxyl group-containing polyamide resin production solution. . The reaction solution was cooled to room temperature and then charged into 500 parts of methanol.

（式中Ｘは水酸基または水素原子を表す。）
で表される本発明のフェノール性水酸基含有ポリアミド樹脂（Ａ）を析出させた。この析出した樹脂を更にメタノール５００部で洗浄した後メタノール還流して精製した。得られたポリアミド樹脂（Ａ）の得量は１６２部、固有粘度は０．５１ｄｌ／ｇ（ジメチルアセトアミド溶液、３０℃）であり、式中、ｍの値は約２０、ｎの値も約２０、エポキシ基に対する水酸基当量は７０４ｇ／ｅｑであった。

(In the formula, X represents a hydroxyl group or a hydrogen atom.)
The phenolic hydroxyl group-containing polyamide resin (A) represented by the present invention was precipitated. The precipitated resin was further washed with 500 parts of methanol and purified by refluxing with methanol. The amount of the obtained polyamide resin (A) is 162 parts, the intrinsic viscosity is 0.51 dl / g (dimethylacetamide solution, 30 ° C.). In the formula, the value of m is about 20, and the value of n is also about 20 The hydroxyl group equivalent to the epoxy group was 704 g / eq.

Comparative Example 1
The reaction was carried out in the same manner as in Example 1 except that the amount of 3,4'-diaminodiphenyl ether used was 102 parts, and the following formula (3)

で表される芳香族ポリアミド樹脂（Ｂ）を析出させた。この析出した樹脂を更にメタノール５００部で洗浄した後メタノール還流して精製した。得られたポリアミド樹脂（Ｂ）の得量は１６５部、固有粘度は０．５５ｄｌ／ｇ（ジメチルアセトアミド溶液、３０℃）であり、式中、ｍの値は約２０、ｎの値は約２０、エポキシ基に対する水酸基当量は７１９ｇ／ｅｑであった。

The aromatic polyamide resin (B) represented by these was deposited. The precipitated resin was further washed with 500 parts of methanol and purified by refluxing with methanol. The amount of the obtained polyamide resin (B) was 165 parts, and the intrinsic viscosity was 0.55 dl / g (dimethylacetamide solution, 30 ° C.). In the formula, the value of m was about 20, and the value of n was about 20 The hydroxyl group equivalent to the epoxy group was 719 g / eq.

Example 2 and Comparative Example 2
The aromatic polyamide resins (A) and (B) obtained in Example 1 and Comparative Example 1 are represented by the following formula (4) as an epoxy resin.

で表されるエポキシ樹脂ＮＣ−３０００−Ｈ（日本化薬株式会社製、エポキシ当量２９０ｇ／ｅｑ、軟化点７０℃、ｐの値２．５）を、硬化促進剤として２−フェニル−４，５−ジヒドロキシメチルイミダゾール（２ＰＨＺ）を、また溶剤としてシクロペンタノンを表１に示される組成で混合しワニス（１）、（２）を得た。

An epoxy resin NC-3000-H (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 290 g / eq, softening point 70 ° C., p value 2.5) as a curing accelerator is 2-phenyl-4,5 -Dihydroxymethylimidazole (2PHZ) and cyclopentanone as a solvent were mixed in the composition shown in Table 1 to obtain varnishes (1) and (2).

Table 1
Examples Comparative examples
2 2
Varnish (1) (2)
NC-3000-H 100 100
Polyamide resin (A) 243
Polyamide resin (B) 248
2PHZ 2 2
Cyclopentanone 345 350

  The varnishes (1) and (2) were stored at 60 ° C., and the solution viscosity at 25 ° C. was measured every 24 hours using an E-type viscometer. The results shown in Table 2 were obtained.

Table 2
Varnish (1) (2)
Solution viscosity (25 ° C / mPa · s)
0 hours later 7200 7400
24 hours later 7200 8500
48 hours later 7300 11200
72 hours later 7500 13500

Example 3 and Comparative Example 3
The above varnishes (1) and (2) are applied on a PET film so that the thickness after drying is 50 μm, and cured by heating at 180 ° C. for 1 hour, and the PET film is removed to obtain a sheet-like sample. Got. All of the obtained samples did not crack even when bent, and had sufficient film forming ability. This cured product was tested for flame retardancy according to UL94-VTM. Moreover, the glass transition temperature of these samples was measured by DMA (dynamic viscoelasticity measuring device). The results are shown in Table 3.

Table 3
Example 3 Comparative Example 3
Varnish (1) (2)
Flame retardant test V-0 V-0
Glass transition temperature (° C.) 245 248

Claims (12)

Following formula (1)

(In the formula, m and n are average values, m + n is a positive number of 2 to 200, and n is a positive number of 0.1 or more. Ar ¹ and Ar ³ are divalent aromatic groups, Ar ^2. Is a divalent aromatic group having a phenolic hydroxyl group, and Ar ⁴ represents the same meaning as Ar ¹ or Ar ^2. )
An aromatic polyamide resin for an epoxy resin curing agent having a structure represented by: An epoxy resin composition containing an epoxy resin (component (a)) and a curing agent of formula (1) (component (b)). Component (a) is a novolak type epoxy resin, a xylylene skeleton-containing phenol novolak type epoxy resin, a biphenyl skeleton containing novolak type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a tetramethylbiphenol type epoxy resin, and triphenylmethane. The epoxy resin composition according to claim 2, which is at least one selected from the group consisting of type epoxy resins. The epoxy resin composition according to any one of claims 2 to 3, wherein the hydroxyl group equivalent in the component (b) is 0.7 to 1.2 equivalents relative to 1 equivalent of the epoxy group in the component (a). . The epoxy resin composition according to any one of claims 2 to 4, comprising a curing accelerator. A varnish obtained by dissolving the epoxy resin composition according to any one of claims 2 to 5 in a solvent. The sheet | seat which has a layer which consists of a composition of any one of Claims 2-5 on both surfaces or one side of a planar support body. The sheet according to claim 7, wherein the planar support is a polyimide film. The sheet according to claim 7, wherein the planar support is a metal foil. The sheet according to claim 7, wherein the planar support is a release film. A prepreg obtained by impregnating a varnish according to claim 6 into a substrate and drying by heating. Hardened | cured material formed by hardening | curing the epoxy resin composition of any one of Claims 2-5.