JPH10147765A - Production of epoxy adhesive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an epoxy adhesive film which can form a film having excellent heat resistance and chemical resistance. SOLUTION: This production process comprises mixing a film-forming high- molecular-weight epoxy polymer obtained by polymerizing a mixture obtained by mixing a difunctional epoxy resin with a bifunctional phenol in an epoxy/ phenolic hydroxyl ratio of 1/0.9 to 1/1.1 by heating in the presence of a catalyst in a solvent and having a weight-average molecular weight of 50,000 or above (in terms of the polystyrene as measured by gel permeation chromatography(GPC) with an isocyanate having at least two isocyanato groups and dissolved in acetylacetone, a polyfunctional epoxy resin and a curing agent, coating at least either surface of a supporting film with the resulting mixture and removing the solvent from the wet film by driving.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an epoxy adhesive film.

[0002]

2. Description of the Related Art With respect to high molecular weight epoxy polymers, for example, US Pat. No. 3,277,048 discloses a bifunctional epoxy resin having a molecular weight of 30,30 obtained by reacting a brominated bisphenol or a chlorinated bisphenol. It is described that a flame-retardant epoxy resin cured product having good mechanical properties is obtained by blending 2,000 or more thermoplastic resins. The polymer obtained in Examples has a molecular weight of 61,000, and the obtained sheet Has a thickness of 0.125 inch (about 3 mm).

[0003] A method for producing a high-molecular-weight epoxy polymer from a relatively low-molecular-weight bifunctional epoxy resin and a bifunctional phenol as raw materials is generally called a two-stage method.
U.S. Pat. No. 2,615,008 discloses that sodium hydroxide is used as a polymerization catalyst, and 150 to 20 without solvent.
By reacting at 0 ° C., the epoxy equivalent is 5,60.
It is stated that a high molecular weight epoxy polymer of 0 is obtained.

In US Pat. No. 3,306,872, methyl ethyl ketone or ethylene glycol monomethyl ether is used as a solvent, the solid content of the solution is 20 to 60%, and an alkali metal or benzyltrimethyl ammonium is used as a catalyst. Using a hydroxide or phenolate, the polymerization reaction temperature is 75 to 150 ° C.,
The weight average molecular weight of the produced high molecular weight epoxy polymer is 50,000 to 100,000 as measured by a viscosity method.

Further, Japanese Patent Application Laid-Open No. 54-52200 discloses that
It is described that a high molecular weight epoxy polymer having an average molecular weight of 45,500 was obtained using ethylene glycol monoethyl ether as a solvent. Japanese Patent Application Laid-Open No. 60-118575 discloses methyl isobutyl ketone, cyclohexanone, ethylene glycol as a solvent. It is described that a high molecular weight epoxy polymer having an average molecular weight of 31,000 at the maximum was obtained using monoethyl ether.
No. 23, using methyl ethyl ketone as a solvent,
It was described that a high molecular weight epoxy polymer having an average molecular weight of 53,200 was obtained. Japanese Patent Application Laid-Open No. 60-144324 discloses that a high molecular weight epoxy polymer having an average molecular weight of 66,000 was obtained using methyl ethyl ketone as a solvent. Is described. In all four cases, the average molecular weight was measured by gel permeation chromatography.

A method for producing an epoxy resin sheet using a high molecular weight epoxy polymer is disclosed in Japanese Patent Application Laid-Open No. 51-8 / 1981.
As disclosed in Japanese Patent No. 7560, a linear high-molecular-weight epoxy polymer and a low-molecular-weight epoxy resin are heated and melted, and an organic carboxylate is mixed.
Methods for producing 5 mm sheets are known. The resulting sheet has a tensile strength of about 10 MPa and an elongation of 350
870%, and the molecular weight of the linear high molecular weight epoxy polymer is 30,000-250,000.

[0007] As a method for imparting thermosetting properties by reacting isocyanates with hydroxyl groups in a polymer, 1947
By Otto Bayer (O.Bayer: Das Di-i)
socyanat-Polyadditionsverfahren: Angewandte Chemie,
A59,257,1947). A method of obtaining a cured product by mixing isocyanates with an epoxy resin is described in US Pat. No. 2,594,979.

A method for crosslinking a high molecular weight epoxy polymer using isocyanates as a crosslinking agent is disclosed in
As described in JP-A-5-40752, it is known to blend a polyisocyanate with a methyl ethyl ketone solution (solid content concentration: 35%) of a phenoxy resin having an average molecular weight of 50,000 to 150,000.

[0009] JP-A-54-117597, JP-B-1-19816 and JP-A-2-147616 disclose epoxy resins and high-molecular-weight phenoxy resins.
Alternatively, a method using an unsaturated isocyanate or a masked isocyanate in a mixture thereof is disclosed.

[0010] Japanese Patent Publication No. 1-19806 discloses that a phenoxy resin is modified with an unsaturated isocyanate to give a film-forming ability to obtain a cured film.

The method of inactivating the active isocyanate groups of the isocyanates at room temperature by masking (blocking) is described in the above-mentioned article by Otto Bayer in 1947.

A halogenated bifunctional epoxy resin and a halogenated bifunctional phenol are blended so that the ratio of epoxy group / phenol hydroxyl group is 1 / 0.9 to 1 / 1.1. Gel permeation chromatography (GPC) with film-forming ability obtained by heating and polymerizing at room temperature
High-molecular-weight epoxy polymers having a styrene-equivalent weight average molecular weight of 50,000 or more according to the method described in JP-A-4-120124, JP-A-4-120125, JP-A-5-93041, and Japanese Patent Laid-Open No. 5-
It is disclosed by Japanese Patent No. 93042.

[0013]

Among the prior art, the molecular weight obtained by reacting a bifunctional epoxy resin with a brominated bisphenol or chlorinated bisphenol described in US Pat. No. 3,277,048. A method of obtaining a flame-retardant epoxy resin cured product having good mechanical properties by blending 30,000 or more thermoplastic resins does not use a solvent at the time of synthesis. In this method, a film having sufficient strength is used. A high molecular weight epoxy polymer having a high molecular weight was not obtained until it had a forming ability, and the molecular weight of the polymer obtained in Examples was set to 61,000, but the measurement method was not described. , The numbers are not reproducible.

[0014] For example, in US Pat. No. 2,615,008, which is referred to as a two-stage method, no solvent is used in the synthesis, and the average molecular weight of the polymer is estimated to be about 11,000. Is done. In this method, a high-molecular-weight epoxy polymer having a linearly increased molecular weight cannot be obtained until the film has sufficient strength to form a film.

The viscosity method described in US Pat. No. 3,306,872 for measuring the weight average molecular weight of the produced high molecular weight epoxy polymer largely depends on the setting of parameters used in the calculation, It is not an accurate measurement method and has no reproducibility.

Further, Japanese Patent Application Laid-Open Nos. 54-52200, 60-118575 and 60-1443 are disclosed.
The average molecular weight described in JP-A No. 23 and JP-A-60-144324 is measured by gel permeation chromatography, but the measurement conditions and the calculation method are not described, and there is no reproducibility.

The method of producing an epoxy resin sheet using a high molecular weight epoxy polymer, disclosed in Japanese Patent Application Laid-Open No. 51-87560, does not disclose a method for synthesizing a high molecular weight epoxy polymer. The method for measuring the molecular weight is not clear.

Japanese Patent Publication No. 1-19806 discloses that a phenoxy resin is modified with an unsaturated isocyanate to give a film-forming ability to obtain a cured film. Since the phenoxy resin used is dissolved in methyl ethyl ketone, the phenoxy resin referred to here has no film-forming ability, and even in this method, the phenoxy resin has a high linearity until it has sufficient strength to form a film. A high molecular weight epoxy polymer having a reduced molecular weight cannot be obtained.

A high-molecular-weight epoxy polymer having a weight-average molecular weight in terms of styrene of 50,000 or more by gel permeation chromatography (GPC) and a method for producing the same are described in JP-A-4-120124 and JP-A-4-120125. JP-A-5-93041 and JP-A-5-9
Although disclosed by Japanese Patent No. 3042, the high molecular weight epoxy polymer obtained by this method is thermoplastic and has sufficient strength, but has a problem that heat resistance and chemical resistance are low.

An object of the present invention is to provide a method for producing an epoxy adhesive film having excellent heat resistance and chemical resistance and having a film forming ability.

[0021]

The method for producing an epoxy adhesive film according to the present invention comprises the steps of preparing a bifunctional epoxy resin and a bifunctional phenol by mixing epoxy group / phenol hydroxyl group = 1/0.
9 to 1 / 1.1, in the presence of a catalyst,
A high molecular weight epoxy polymer having a weight-average molecular weight in terms of styrene of 50,000 or more as determined by gel permeation chromatography (GPC) having a film-forming ability obtained by heating and polymerizing in a solvent, and two or more dissolved in acetylacetone After blending an isocyanate having an isocyanate group, a polyfunctional epoxy resin, and a curing agent, the mixture is applied to one or both surfaces of a support film, and the solvent is dried and removed.

[0022]

DETAILED DESCRIPTION OF THE INVENTION As the bifunctional epoxy resin used in the present invention, any compound having two epoxy groups in the molecule can be used. For example, bisphenol A type epoxy resin, Bisphenol F type epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, etc., diglycidyl etherified bifunctional phenols, diglycidyl etherified bifunctional alcohols, and the like. There are halides and hydrogenated products. Two or more of these compounds can be used in combination.

As the bifunctional phenol, any compound having two phenolic hydroxyl groups can be used. For example, monocyclic bifunctional phenols such as hydroquinone, resorcinol, catechol, and polycyclic bifunctional phenols can be used. Phenol bisphenol A, bisphenol F
And their halides and substituted alkyl groups. Two or more of these compounds can be used in combination.

The equivalent ratio between the bifunctional epoxy resin and the bifunctional phenol is as follows: epoxy group / phenolic hydroxyl group = 1 /
The range is 0.9 to 1 / 1.1. In this equivalent ratio, when the phenolic hydroxyl group is less than 0.9, the polymer does not linearly increase in molecular weight, causes a side reaction to be crosslinked, and becomes insoluble in a solvent. Does not progress.

As the polymerization catalyst for the bifunctional epoxy resin and the bifunctional phenol, those having a catalytic activity to promote the reaction between the epoxy group and the phenolic hydroxyl group, for example, alkali metal compounds, alkaline earth metal compounds, imidazoles , Organic phosphorus compounds, secondary amines, tertiary amines, quaternary ammonium salts, and the like. Among them, alkali metal compounds are the most preferred catalysts because side reactions are unlikely to occur and the molecular weight is high, and hydroxides of sodium, lithium and potassium, halides,
Organic acid salts, alcoholates, phenolates, hydrides, borohydrides, amides and the like. These catalysts can be used in combination. The amount of the catalyst is generally about 0.0001 to 0.2 mol per 1 mol of the epoxy resin. If the amount is less than 0.0001 mol, the polymerization reaction becomes extremely slow, and if it exceeds 0.2 mol, it is difficult to form a linear polymer.

The amide solvent used in the present invention can dissolve a bifunctional epoxy resin and a bifunctional phenol, for example, formamide, N-methylformamide, N, N-dimethylformamide, acetamide,
N-methylacetamide, N, N-dimethylacetamide, N, N, N ', N'-tetramethylurea, 2-pyrrolidone, N-methylpyrrolidone, carbamic acid esters and the like can be used. These solvents can be used in combination, and further can be used in combination with other ketone solvents or ether solvents.

The solid content concentration in the polymerization reaction using a solvent must be in the range of 10 to 50% by weight.
If the amount is less than 10% by weight, the solution viscosity at the time of application becomes extremely low, and application becomes impossible. If it exceeds 50% by weight, side reactions increase and it is difficult to increase the molecular weight into a linear one. The tendency for the side reaction to increase is likely to occur as the solid content concentration increases, and is preferably 40% by weight or less, more preferably 30% by weight or less.

The polymerization reaction temperature must be 60 to 150 ° C. If it is lower than 60 ° C., the high molecular weight reaction is remarkably slow, and if it exceeds 150 ° C., side reactions increase and it is difficult to increase the molecular weight into a linear one. .

The isocyanates used in the present invention include those having two isocyanate groups in the molecule, for example,
Diisocyanates include hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate, phenylene diisocyanate, tolylene diisocyanate,
Trimethylhexamethylene diisocyanate, naphthalene diisocyanate, diphenyl ether diisocyanate, diphenylpropane diisocyanate, biphenyl diisocyanate, and isomers, alkyl substitutes, halides, hydrogenated benzene rings thereof, and the like can be used. Further, triisocyanates having three isocyanate groups, tetraisocyanates having four isocyanate groups, and the like can be used, and these can be used in combination.

When an isocyanate is used as a crosslinking agent, the reactivity with an alcoholic hydroxyl group is so high that the crosslinking reaction proceeds at room temperature and gelation of the epoxy resin solution may occur. In the present invention, this isocyanate group is dissolved in acetylacetone and used to deactivate the isocyanate at room temperature, and the storage stability of the varnish can be enhanced. Further, when a solution obtained by dissolving isocyanates with acetylacetone is used at a temperature in the range of room temperature to 130 ° C. for 10 minutes to 10 hours, the storage stability of the varnish can be further enhanced. Further, it is easy to volatilize when dried, and the ratio of remaining on the film is small. The concentration of the isocyanates dissolved in acetylacetone is preferably in the range of 10 to 90% by weight. 10% by weight
If the amount is less than acetylacetone, the amount of acetylacetone used is too large to be economical.

The isocyanate or the isocyanate dissolved with acetylacetone is added to the high molecular weight epoxy polymer in an amount of 0.1 isocyanate equivalent to 1 alcoholic hydroxyl equivalent of the high molecular weight epoxy polymer.
It is preferably in the range of 1-2. If it is less than 0.1, crosslinking is difficult, and if it exceeds 2, isocyanates remain in the film, lowering heat resistance and chemical resistance.

The polyfunctional epoxy resin used in the present invention includes:
Compounds having two or more epoxy groups in the molecule, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin,
Phenol novolak epoxy resin, cresol novolak epoxy resin, bisphenol A novolak epoxy resin, bisphenol F novolak epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin,
Glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, diglycidyl etherified product of bifunctional phenols, diglycidyl etherified product of difunctional alcohols, and their halides, hydrogen Additives and the like can be used. These compounds may be used in combination of two or more, and may also contain components other than the bifunctional epoxy resin as impurities. The blending amount of the polyfunctional epoxy resin with respect to the high molecular weight epoxy polymer is in the range of 1 to 200 parts by weight based on 100 parts by weight of the high molecular weight epoxy polymer.

Typical examples of the curing agent for the polyfunctional epoxy resin include polyfunctional phenols, amines, imidazole compounds, and acid anhydrides. Polyfunctional phenols include monocyclic bifunctional phenol hydroquinone, resorcinol, catechol, polycyclic bifunctional phenol bisphenol A, bisphenol F, naphthalene diols, bisphenols and their halides, alkyl-substituted products, Novolak resins and resole resins which are polycondensates of these phenols and aldehydes can be used. Examples of the amines include aliphatic primary amines, secondary amines, tertiary amines, and aromatic primary amines. Secondary amines, tertiary amines, guanidines, urea derivatives, etc., specifically, triethylenetetramine, diaminodiphenylmethane, diaminodiphenylether,
Dicyandiamide, tolylbiguanide, guanylurea,
Dimethyl urea and the like can be used.
Alkyl-substituted imidazole, benzimidazole and the like can be used, and as the acid anhydride, phthalic anhydride, hexahydrophthalic anhydride, pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride and the like can be used. If necessary, a curing accelerator is used, for example, a tertiary amine, imidazole, quaternary ammonium salt, or the like. The compounding amount of the curing agent is 1 to 70 parts by weight based on 100 parts by weight of the polycyclic epoxy resin. In addition, if necessary,
Flame retardants and inorganic fillers can also be blended. Examples of flame retardants include bromine compounds such as tetrabromobisphenol A, decabromodiphenyl ether, brominated epoxy resins, and brominated phenol resins, and aluminum hydroxide, magnesium hydroxide, and the like. Can be used.

The high-molecular-weight epoxy polymer, isocyanates dissolved in acetylacetone, a polyfunctional epoxy resin, a curing agent, and a curing accelerator are mixed so that the varnish does not gel.

[0035]

【Example】

Example 1 A bisphenol A type epoxy resin (epoxy equivalent: 171.3) was used as a bifunctional epoxy resin, and bisphenol A (hydroxyl equivalent: 1) was used as a bifunctional phenol.
14.0), epoxy group / phenol hydroxyl group = 1
/1.01 and using N, N-dimethylacetamide as a solvent in the presence of 0.065 mol of lithium hydroxide as a catalyst with respect to 1 mol of epoxy resin, and a solid content concentration of the solution. The composition was adjusted to 20% by weight, and the viscosity was 6,800 mPa · s.
Gel permeation chromatography (G) having film-forming ability obtained by heating and polymerizing at 0 ° C. for 10 hours in the solvent.
PC) method, the weight average molecular weight in terms of styrene is 185,
000 high molecular weight epoxy polymer having a reduced viscosity of 1.08 in NN-dimethylacetamide at 30 ° C.
dl / g. Using this high-molecular-weight epoxy polymer and a 40% by weight solution of isophorone diisocyanate dissolved in acetylacetone, one equivalent of the alcoholic hydroxyl group of the high-molecular-weight epoxy polymer was added with 0.1% of isocyanate group.
It was blended to be 5 equivalents. Cresol novolak type epoxy resin (epoxy equivalent: 19) was used as a polyfunctional epoxy resin with respect to 100 parts by weight of a high molecular weight epoxy polymer.
30 parts by weight of 5) and 20 parts by weight of a phenol novolak resin (hydroxyl equivalent: 106) as a curing agent were blended to obtain a varnish. This varnish was applied to one side of a polypropylene film having a thickness of 50 μm, and dried in a dryer at 100 ° C.
Drying was performed for 0.5 hr to obtain a semi-cured epoxy adhesive film having a thickness of 45 μm.

Example 2 A bisphenol A type epoxy resin (epoxy equivalent: 171.3) was used as a bifunctional epoxy resin, and resorcinol (hydroxyl equivalent: 11) was used as a bifunctional phenol.
0), epoxy group / phenol hydroxyl group = 1/1.
And N, N-dimethylacetamide as a solvent in the presence of 0.065 mol of lithium hydroxide as a catalyst with respect to 1 mol of epoxy resin,
The composition was adjusted so that the solid content of the solution was 30% by weight, and the viscosity was 2,200 mPa · s.
Permeation chromatography (GP) having a film-forming ability obtained by heating and polymerizing in a solvent for 10 hours.
The weight average molecular weight in terms of styrene by the method C) is 191,0.
00 high molecular weight epoxy polymer, the reduced viscosity of which is:
1.24 d in N, N-dimethylacetamide at 30 ° C.
1 / g. Using this high molecular weight epoxy polymer and a 40% by weight solution of isophorone diisocyanate dissolved in acetylacetone, 0.5 equivalent of isocyanate group was added to 1 equivalent of alcoholic hydroxyl group of high molecular weight epoxy polymer.
It was blended to be equivalent. High molecular weight epoxy polymer 1
As a polyfunctional epoxy resin, a brominated bisphenol A type epoxy resin (epoxy equivalent: 40
30 parts by weight of 0) and 2 parts by weight of dicyandiamide (equivalent: 21) as a curing agent were mixed to obtain a varnish. This varnish was applied on one side of a 50 μm thick polypropylene film, and dried in a dryer at 100 ° C. for 0.5 hr to obtain a 45 μm thick semi-cured epoxy adhesive film.

Example 3 A bisphenol A type epoxy resin (epoxy equivalent: 171.3) was used as a bifunctional epoxy resin, and tetrabromobisphenol A (hydroxyl equivalent: 272) was used as a bifunctional phenol. The phenolic hydroxyl group was mixed so as to be 1 / 1.006, and N, N-dimethylacetamide was used as a solvent in the presence of lithium hydroxide as a catalyst, and the solid concentration of the solution was 30% by weight.
The viscosity is adjusted to 3,500 mP
high molecular weight having a weight average molecular weight in terms of styrene of 285,000 as determined by gel permeation chromatography (GPC) having a film-forming ability obtained by heating and polymerizing in a solvent at 120 ° C. for 10 hours. An epoxy polymer was obtained having a reduced viscosity of 0.81 dl / g in N, N-dimethylacetamide at 30 ° C. A 40% by weight solution of isophorone diisocyanate dissolved in acetylacetone was mixed with this high molecular weight epoxy polymer so that 0.5 equivalent of isocyanate group was equivalent to 1 equivalent of alcoholic hydroxyl group of high molecular weight epoxy polymer. For 100 parts by weight of the high molecular weight epoxy polymer, 50 parts by weight of a bisphenol A type epoxy resin (epoxy equivalent: 171.3) as a polyfunctional epoxy resin and 2 parts by weight of imidazole (equivalent: 68) as a curing agent were blended. I got a varnish. This varnish was applied on one side of a polypropylene film having a thickness of 50 μm, and dried in a dryer at 100 ° C. for 0.5 h.
Drying was performed under the conditions of r to obtain a semi-cured epoxy adhesive film having a thickness of 42 μm.

Example 4 A bisphenol A type epoxy resin (epoxy equivalent: 171.3) was used as a bifunctional epoxy resin, and bisphenol A (hydroxyl equivalent: 1) was used as a bifunctional phenol.
14.0), epoxy group / phenol hydroxyl group = 1
/1.01 and using N, N-dimethylacetamide as a solvent in the presence of 0.065 mol of lithium hydroxide as a catalyst with respect to 1 mol of epoxy resin, and a solid content concentration of the solution. The composition was adjusted to 20% by weight, and the viscosity was 6,800 mPa · s.
Gel permeation chromatography (G) having film-forming ability obtained by heating and polymerizing at 0 ° C. for 10 hours in the solvent.
PC) method, the weight average molecular weight in terms of styrene is 185,
000 high molecular weight epoxy polymer having a reduced viscosity of 1.0 in N, N-dimethylacetamide at 30 ° C.
It was 8 dl / g. This high molecular weight epoxy polymer,
Using a 40% by weight solution of isophorone diisocyanate dissolved in acetylacetone heated at 120 ° C. for 8 hours, the alcoholic hydroxyl group 1 of the high molecular weight epoxy polymer was used.
The isocyanate group was blended so as to be 0.5 equivalent to the equivalent. 30 parts by weight of a cresol novolak type epoxy resin (epoxy equivalent: 195) as a polyfunctional epoxy resin and 20 parts by weight of a phenol novolak resin (hydroxyl equivalent: 106) as a curing agent for 100 parts by weight of a high molecular weight epoxy polymer. Then, a varnish was obtained. This varnish was applied on one surface of a polypropylene film having a thickness of 50 μm, and dried in a drier at 100 ° C. for 0.5 hr to obtain a semi-cured epoxy adhesive film having a thickness of 42 μm.

Comparative Example 1 A high-molecular-weight epoxy polymer was added to a phenoxy resin YP
50 (manufactured by Toto Kasei Co., Ltd., trade name, average molecular weight; 6)
8,000), using isophorone diisocyanate as an isocyanate having two or more isocyanate groups.
As a masking agent, methyl ethyl ketone oxime was added in an amount of 1.0
It was used in an amount equivalent to 0.5 equivalent of an isocyanate group per 1 equivalent of an alcoholic hydroxyl group of a high molecular weight epoxy polymer. 30 parts by weight of a cresol novolak type epoxy resin (epoxy equivalent: 195) as a polyfunctional epoxy resin and 20 parts by weight of a phenol novolak resin (hydroxyl equivalent: 106) as a curing agent for 100 parts by weight of a high molecular weight epoxy polymer. Then, a varnish was obtained. This varnish was applied on one surface of a polypropylene film having a thickness of 50 μm, and dried in a drier at 100 ° C. for 0.5 hr to obtain a semi-cured epoxy adhesive film having a thickness of 42 μm. However, this adhesive film was brittle and difficult to handle, and could not be evaluated.

Comparative Example 2 A brominated bisphenol A type epoxy resin (epoxy equivalent: 400) was used as the halogenated bifunctional epoxy resin, and tetrabromobisphenol A (hydroxyl equivalent: 272) was used as the halogenated bifunctional phenol. , Epoxy group / phenol hydroxyl group = 1 / 1.02, and lithium hydroxide as a catalyst was added to the epoxy resin 1
Using N, N-dimethylacetamide as a solvent in the presence of 0.065 mol with respect to the mol, the composition was adjusted so that the solid concentration of the solution was 30% by weight, and the viscosity was 350 mPa · s. A high molecular weight epoxy polymer having a film-forming ability and having a weight average molecular weight in terms of styrene of 155,000 by gel permeation chromatography (GPC) was obtained by heating and polymerizing in a solvent at 120 ° C. for 10 hours. The reduced viscosity was 1.22 dl / g in N, N-dimethylacetamide at 30 ° C. Isophorone diisocyanate alone is used as the isocyanate having two or more isocyanate groups in the high molecular weight epoxy polymer, and the isocyanate group is added to one equivalent of the alcoholic hydroxyl group of the high molecular weight epoxy polymer.
It was blended to be 5 equivalents. Cresol novolak type epoxy resin (epoxy equivalent: 19) was used as a polyfunctional epoxy resin with respect to 100 parts by weight of a high molecular weight epoxy polymer.
30 parts by weight of 5) and 20 parts by weight of a phenol novolak resin (hydroxyl equivalent: 106) as a curing agent were blended to obtain a varnish. This varnish gelled in 3 hours,
No film could be obtained.

(Test Method) The measurement methods in Examples and Comparative Examples, the characteristics of the adhesive film, and the storage stability of the varnish were tested by the following methods. Table 1 shows some of the test results.・ Viscosity Using an EMD type viscometer (Tokyo Keiki Co., Ltd.), 25
Measured in ° C. -Styrene-equivalent weight average molecular weight by gel permeation chromatography (GPC) method The column used for gel permeation chromatography (GPC) is TSKgel G6000 + G5000 + G400.
0 + G3000 + G2000. The eluent contains N,
The sample concentration was 2% by weight using N-dimethylacetamide. After determining the relationship between the molecular weight and the elution time using styrenes having different molecular weights, the elution time of the sample was measured, the molecular weight was estimated, and the result was defined as the weight average molecular weight in terms of styrene. -Reduced viscosity The high molecular weight epoxy polymer was measured using an Ubbelohde viscometer. -Tensile strength and elongation Tensile strength and elongation were measured using a film manufactured by Toyo Baldwin Co., Ltd.
10 mm, and the pulling speed was 5 mm / min. Tg The glass transition point (Tg) is 910, which is a differential scanning
(Manufactured by DuPont, trade name).・ Adhesive strength TSA-18 (trade name, manufactured by Furukawa Circuit Foil Co., Ltd.), which is a copper foil of 18 μm, is laminated on a semi-cured epoxy adhesive film and laminated by heating and pressing at 170 ° C., 2 MPa, and 30 minutes. Integrated, copper foil with a width of 10mm,
The film was pulled in the direction of 90 °, and the peel strength was determined.・ Chemical resistance The cured sample film is treated with methyl ethyl ketone, N, N
-Dipped in each of dimethylacetamide, toluene, acetone, methylene chloride, 10% hydrochloric acid, and 10% sodium hydroxide for 30 minutes, the surface was visually observed, and those without swelling and dissolution were judged to be good. -Storage stability of varnish The varnish was allowed to stand at room temperature for 7 days, stirred, visually observed, and those not gelled were judged to be good.

[0042]

[Table 1]

[0043]

As described above, according to the present invention, it is possible to provide a method for producing an adhesive film having excellent strength and adhesiveness, and excellent in heat resistance and chemical resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 175: 04)

Claims (8)

[Claims] (1) An epoxy group / phenol hydroxyl group = 1 / 0.9 to 1 /
The polymer was heated in a solvent in the presence of a catalyst and polymerized in the presence of a catalyst to obtain a film-forming ability. The gel-permeation chromatography (GPC) method has a weight average molecular weight in terms of styrene of 50,000. After blending the above high molecular weight epoxy polymer, isocyanates having two or more isocyanate groups dissolved in acetylacetone, a polyfunctional epoxy resin, and a curing agent, the mixture is applied to one or both surfaces of a support film, and a solvent is applied. A method for producing an epoxy adhesive film, comprising: 2. The method for producing an epoxy adhesive film according to claim 1, wherein the weight average molecular weight in terms of styrene of the high molecular weight epoxy polymer is 100,000 or more as determined by gel permeation chromatography (GPC). . 3. The method for producing an epoxy adhesive film according to claim 1, wherein the polymerization reaction solvent is an amide solvent. 4. The reduced viscosity of the high molecular weight epoxy polymer is as follows:
It is 0.50 dl / g or more, The Claims 1-3 characterized by the above-mentioned.
The method for producing an epoxy adhesive film according to any one of the above. 5. The reduced viscosity of the high molecular weight epoxy polymer is as follows:
5. It is 0.80 dl / g or more.
The method for producing an epoxy adhesive film according to any one of the above. 6. The method for producing an epoxy adhesive film according to claim 1, wherein the bifunctional phenol is brominated bisphenol A. 7. The method for producing an epoxy adhesive film according to claim 1, wherein isocyanates dissolved in acetylacetone are further heated. 8. The method for producing an epoxy adhesive film according to claim 1, wherein the support film is a copper foil, and the coated surface is only a roughened surface of the copper foil.