JPH0525368A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To provide an epoxy resin composition excellent in heat and impact resistance and adhesion. CONSTITUTION:An epoxy resin composition is obtained by blending a high- molecular weight epoxy polymer prepared by thermally polymerizing a bifunctional epoxy resin with bifunctional phenols at 1:(0.9-1.1) blending equiv. ratio of epoxy groups/phenolic hydroxyl groups in the bifunctional epoxy resin and the bifunctional phenols, in the presence of a catalyst, in an amide-based or a ketone-based solvent having >=130 deg.C boiling point at <=50wt.% reaction solid concentration with a polyfunctional epoxy resin and a curing agent. The average molecular weight of the high-molecular weight epoxy polymer is >=70,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition used for adhesives, insulating materials, paints, molded products, films and the like.

[0002]

2. Description of the Related Art A method for producing a high molecular weight epoxy resin from a relatively low molecular weight difunctional epoxy resin and a bifunctional phenol as a raw material is generally called a two-step method, and the first reference to this method is US Pat. , 615,008, and in Japan, it is JP-B 28-4494 by the same applicant. In this document, sodium hydroxide is used as a polymerization catalyst, and 150-2
By reacting at 00 ° C, the epoxy equivalent becomes 5,6.
A high molecular weight epoxy resin of 00 has been obtained. The average molecular weight of this resin can be estimated to be about 11,000. Documents which describe the use of solvents include US Pat. No. 3,306,872. Japanese Patent Application Laid-Open No. 54-5 is a patent document in which a solvent is used in the examples.
2200, JP-A-60-118757, JP-A-60-144323, and JP-A-60-1443.
No. 24 publication and the like. The solvents used in these documents are methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether and the like. These solvents are classified into ketone type and ether type (cellosolve type) solvents.

In US Pat. No. 3,306,872, either methyl ethyl ketone or ethylene glycol monomethyl ether is used as a solvent, and the solid content concentration of the solution is 20 to 60%. As the catalyst, a hydroxide or phenolate of alkali metal or benzyltrimethylammonium is used. Further, the polymerization reaction temperature is set to 75 to 150 ° C., and the reaction is continued until the weight average molecular weight of the produced high molecular weight epoxy resin becomes at least 40,000 or more. The average molecular weight is determined by the viscosity method and is measured as 50,000 to 1,000,000. However, it is known that the calculated value of the viscosity method greatly depends on the setting of parameters used in the calculation, and therefore, it cannot be said that the accurate molecular weight is necessarily measured.

Further, as an example in which it is considered that a high molecular weight epoxy resin is obtained by polymerizing in a solvent, JP-A-54-52200 uses ethylene glycol monoethyl ether as a solvent and has an average molecular weight of 45. , 500 high molecular weight epoxy resins were obtained. JP-A-60-118757 describes that a high molecular weight epoxy resin having an average molecular weight of up to 31,000 is obtained by using methyl isobutyl ketone, cyclohexanone and ethylene glycol monoethyl ether as a solvent. JP-A-60-144323 discloses that methyl ethyl ketone is used as a solvent and the average molecular weight is 5
It is described that a 3,200 high molecular weight epoxy resin is obtained, and JP-A-60-144324 discloses that a methyl ethyl ketone is used as a solvent to obtain a high molecular weight epoxy resin having an average molecular weight of 66,000. In each of the above four patent documents, the average molecular weight is measured by gel permeation chromatography, but the measurement conditions and calculation method are not described. The molecular weight obtained by gel permeation chromatography differs greatly depending on the measurement conditions such as the type of filler used and the type of eluent used and the calculation method, and it cannot be said that an accurate value is necessarily measured. The conventionally known high molecular weight epoxy resin is not a linear polymer epoxy resin but a branched polymer epoxy resin, and a film having sufficient strength cannot be formed. Further, in any of the above patent documents, there is no description that the obtained epoxy resin has a film forming ability, and there is no example. Further, since it is dissolved in a solvent other than an amide-based solvent, it is clear that a high molecular weight epoxy resin having a linear high molecular weight has not been obtained by the time it has a film forming ability with sufficient strength.

Next, a method for producing an epoxy resin sheet using a linear high molecular weight epoxy resin is described in JP-A-51-87560. That is, this is a method in which a linear high molecular weight epoxy resin and a low molecular weight epoxy resin are heated and melted and an organic carboxylate is mixed to obtain a sheet having a thickness of 0.3 to 0.5 mm. The properties of the obtained sheet are as follows: tensile strength is about 10 MPa, elongation is 35
It is 0 to 870%. The linear high molecular weight epoxy resin used here has a molecular weight of 30,000 to 250,000.
However, there is no description about the method for measuring the molecular weight, and it cannot be compared with the molecular weight of the linear high molecular weight epoxy resin in the present invention. Further, there is no example in which a polyfunctional epoxy resin and a curing agent are mixed with an epoxy polymer capable of forming a film.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a high molecular weight epoxy polymer which has been polymerized in a linear manner to have a film-forming ability of sufficient strength, which was not obtained by a conventional method, and a thermosetting component. The purpose of the present invention is to provide an epoxy resin composition capable of producing a sufficiently thin film having excellent adhesiveness, heat resistance, and chemical resistance by adding an epoxy resin, a curing agent, and a curing accelerator. To do.

[0007]

In the epoxy resin composition of the present invention, the compounding equivalent ratio of the bifunctional epoxy resin and the bifunctional phenols to the bifunctional epoxy resin and the bifunctional phenols is epoxy group / phenolic hydroxyl group = 1: 0.9 to 1.1, in the presence of a catalyst, in a amide or ketone solvent having a boiling point of 130 ° C. or higher, with a reaction solid content concentration of 50% by weight or less,
It is characterized in that a polyfunctional epoxy resin, a curing agent and a curing accelerator are mixed with a high molecular weight epoxy polymer obtained by heating and polymerizing.

The present invention will be described in detail below. The bifunctional epoxy resin which is a raw material for synthesizing the high molecular weight epoxy polymer in the present invention may be any compound as long as it has two epoxy groups in the molecule, for example, bisphenol A type epoxy resin and bisphenol F. -Type epoxy resin, bisphenol S-type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, and other difunctional phenol diglycidyl ether compounds, difunctional alcohol diglycidyl ether compounds, and their halides , Hydrogenated products, etc. The molecular weight of these compounds may be any. Several kinds of these compounds can be used in combination. Further, components other than the bifunctional epoxy resin may be included as impurities.

The bifunctional phenol which is a raw material for synthesizing the high molecular weight epoxy polymer in the present invention may be any compound having two phenolic hydroxyl groups, for example, monocyclic bifunctional phenol. Examples thereof include hydroquinone, resorcinol, catechol, polycyclic bifunctional phenols bisphenol A, bisphenol F and halides thereof, and alkyl group-substituted products. The molecular weight of these compounds may be any. Several kinds of these compounds can be used in combination. Further, components other than the bifunctional phenols may be included as impurities.

The synthesis catalyst for the high molecular weight epoxy polymer in the present invention may be any compound having a catalytic ability to accelerate the etherification reaction of the epoxy group and the phenolic hydroxyl group, for example, an alkali metal compound. , Alkaline earth metal compounds, imidazoles, organic phosphorus compounds, secondary amines, tertiary amines, and quaternary ammonium salts. Among them, alkali metal compounds are the most preferable catalysts, and examples of alkali metal compounds include hydroxides of sodium, lithium and potassium, halides, organic acid salts, alcoholates, phenolates, hydrides, borohydrides and amides. is there. These catalysts can be used in combination.

The amide solvent which is a reaction solvent for synthesizing the high molecular weight epoxy polymer in the present invention is not particularly limited as long as it can dissolve the starting epoxy resin and phenol at a boiling point of 130 ° C. or higher, but is preferably amide. A solvent or a ketone solvent is preferable. Examples of the amide solvent include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N,
Examples include N-dimethylacetamide, N, N, N ', N'-tetramethylurea, 2-pyrrolidone, N-methylpyrrolidone, and carbamic acid ester. Examples of the ketone solvent include cyclohexanone, acetylacetone, diisobutyl ketone, phorone, isophorone, methylcyclohexanone, acetophenone and the like. These solvents can be used in combination. Further, it may be used in combination with other solvent represented by amide type, ketone type, ether type, alcohol type, ester type and the like.

As a synthesis condition of the high molecular weight ether polymer, the compounding equivalent ratio of the bifunctional epoxy resin and the bifunctional phenol is such that epoxy group / phenolic hydroxyl group = 1: 0.9.
It is desirable that it is ~ 1.1. If the amount is less than 0.9 equivalent, the polymer does not linearly increase in molecular weight, and a side reaction occurs to cause cross-linking and become insoluble in the solvent. If the amount is more than 1.1 equivalents, higher molecular weight does not proceed. The amount of the synthetic reaction catalyst for the synthesis of the high molecular weight epoxy polymer is not particularly limited, but the amount of the catalyst is generally about 0.0001 to 0.2 mol per mol of the epoxy resin. If the amount is less than this range, the high molecular weight reaction is remarkably slow, and if it is more than this range, side reactions increase and the molecular weight does not linearly increase. The synthesis reaction temperature of the high molecular weight epoxy polymer is preferably 60 to 150 ° C. If it is lower than 60 ° C, the high molecular weight reaction is remarkably slow, and if it is higher than 150 ° C, there are many side reactions and the polymer does not linearly increase in molecular weight. The solid content concentration during the synthesis reaction of the high molecular weight epoxy polymer may be 50% or less, preferably 40% or less. More preferably, it is desired to be 30% or less. As the concentration becomes higher, side reactions increase, and it becomes difficult to form a linear polymer having a high molecular weight. Therefore, when carrying out the polymerization reaction at a relatively high concentration and obtaining a linear high molecular weight epoxy polymer, it is necessary to lower the reaction temperature and the catalyst amount.

In the present invention, the high molecular weight epoxy polymer used for forming the resin composition may be separated by precipitation using the solution after the sizing as it is, or by adding the poor solvent of the epoxy polymer to the solution. It may be one. The solvent used for precipitation is not limited to the solvent used for the synthesis, as long as it can precipitate the high molecular weight epoxy polymer. For example, alcohol solvents such as methanol and ethanol, ketone solvents such as acetone and methyl ethyl ketone, hydrocarbon solvents such as pentane, hexane, benzene, toluene, xylene, petroleum ether, chloroform and chlorobenzene, other ether solvents, ester solvents. Alternatively, water and an aqueous solution in which an acid, an alkali, a salt or the like is dissolved in water can be used. Other solvents include acetic acid, acetic anhydride, phenol, nitrobenzene, formamide, acetamide, liquid silicone compounds and the like.

The polyfunctional epoxy resin may be any compound as long as it is a compound 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 novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin , Hydantoin type epoxy resin, isocyanurate type epoxy resin, and other difunctional phenol diglycidyl ether compounds, difunctional alcohol diglycidyl ether compounds, and their halides and hydrogenation Thing, and the like. The molecular weight of these compounds may be any. Several kinds of these compounds can be used in combination. Further, components other than the bifunctional epoxy resin may be included as impurities.

The curing agent in the present invention may be any one as long as it cures an epoxy resin. Typical examples are polyfunctional phenols, amines,
Examples include imidazole compounds and acid anhydrides. Examples of polyfunctional phenols are monocyclic bifunctional phenols such as hydroquinone, resorcinol, catechol, polycyclic bifunctional phenols such as pisphenol A, bisphenol F, naphthalenediols, biphenols and their halides and alkyl groups. There is a substitute. Further, there are novolac and resole which are polycondensates of these phenols and aldehydes.

Examples of amines are aliphatic primary, 2
, Tertiary amines, aromatic primary, secondary, tertiary amines, guanidines, urea derivatives, and the like. Specific examples include triethylenetetramine, diaminodiphenylmethane, diaminodiphenylether, dicyandiamide, tolubiguanide, guanylurea. , Dimethylurea, etc.

Examples of the imidazole compound include alkyl group-substituted imidazole and benzimidazole.

Examples of acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, pyromellitic dianhydride, and benzophenonetetracarboxylic dianhydride. You may mix | blend a hardening accelerator as needed. Typical epoxy resin curing accelerators include tertiary amines, imidazoles, and quaternary ammonium salts. If necessary, flame retardants, inorganic fillers, etc. may be added. Examples of the flame retardant include bromine compounds such as tetrabromobisphenol A, decabromodiphenyl ether, brominated epoxy resin and brominated phenol resin, and metal hydroxides such as aluminum hydroxide and magnesium hydroxide. Further, if necessary, any amount of a solvent other than the synthetic solvent may be added. These high molecular weight epoxy polymer, polyfunctional epoxy resin, curing agent and curing accelerator may be mixed by any method.

An epoxy resin composition obtained by blending a polyfunctional epoxy resin and a curing agent with a high-molecular-weight epoxy polymer having film-forming ability according to the present invention has a thickness not possible with conventional epoxy resin compositions. It is possible to form a film having a thickness of 100 μm or less, and moreover, it has adhesiveness, heat resistance, chemical resistance, solvent resistance and tensile strength that are equal or higher.
Further, by using an epoxy polymer deposited by a poor solvent, a cured resin product having excellent heat resistance and impact resistance can be obtained.

[0020]

The present inventors have found that when a bisphenol A type epoxy resin and a high molecular weight epoxy polymer using bisphenol A as a raw material have a styrene-equivalent weight average molecular weight of more than 100,000 by gel permeation chromatography, an amide solvent It has been confirmed that it does not dissolve in anything other than. At the same time, it was confirmed that when the styrene-equivalent weight average molecular weight exceeds 100,000 and the compound is soluble in a solvent other than the amide solvent, it is a highly branched high molecular weight epoxy polymer. For example, a high molecular weight epoxy polymer obtained by polymerizing a bisphenol A type epoxy resin and bisphenol A at an epoxy group / phenolic hydroxyl group equivalent ratio of 1 / 0.60 to 1 / 0.80 has many branches. It is considered that the high molecular weight epoxy polymer having a styrene-equivalent weight average molecular weight of 110,000 obtained in an equivalence ratio in this range dissolves in methyl ethyl ketone which is a ketone solvent. On the other hand, the equivalent weight ratio of epoxy group / phenolic hydroxyl group was set to 1 / 0.99 to 1 / 1.01, and the styrene-converted weight average molecular weight was 66, which was polymerized in an amide solvent.
A high molecular weight epoxy polymer of 000 is considered a linear high molecular weight epoxy polymer, but is insoluble in methyl ethyl ketone. In order for the linear high molecular weight epoxy polymer to be completely dissolved in methyl ethyl ketone, the styrene-equivalent weight average molecular weight needs to be about 20,000 or less. Although it is currently not possible to accurately measure the degree of branching in a linear polymer, if the molecular weight is the same, the length of the linear portion will become shorter as the number of branches increases, affecting various properties. Conceivable. In terms of physical properties, it is considered that a linear polymer thermoplastic resin and a thermosetting resin, which is a cross-linked polymer having many branches, may be compared. The thermoplastic resin, which is a linear polymer, generally has higher impact resistance and larger elongation than the thermosetting resin.
As a result, most thermoplastics have sufficient strength to form films.

The present inventors conducted the above-mentioned bisphenol A type epoxy resin and a branched high molecular weight epoxy polymer and a linear high molecular weight epoxy polymer by changing the epoxy group / phenolic hydroxyl group equivalent ratio of bisphenol A. As a result of examining the difference between the two, it was possible for the latter to form a film having a sufficient strength of 100 μm or less, whereas the former could not be handled as a film because the strength was weak at 100 μm or less. .

[0022]

EXAMPLES The present invention will now be described in detail based on examples, but the present invention is not limited thereto.

Example 1 177.5 g of a bisphenol A type epoxy resin (epoxy equivalent: 177.5) as a bifunctional epoxy resin, and bisphenol A (hydroxyl group equivalent: as a bifunctional phenol).
115.5) 115.5 g and 1.77 g of sodium hydroxide as an etherification catalyst are added to N, N- which is an amide solvent.
It was dissolved in 547.9 g of dimethylacetamide to make the solid content concentration in the reaction system 30%. While mechanically stirring this, the temperature in the reaction system was kept at 120 ° C. in an oil bath and kept as it was for 4 hours. As a result, the viscosity is 19,7
The reaction was completed by saturating at 00 mPa.s. The weight average molecular weight of the obtained high molecular weight epoxy polymer was 133,00 as measured by gel permeation chromatography.
0, 129000 as measured by light scattering method
Met. The reduced viscosity of the diluted solution was 1.08 dl / g. In this high molecular weight epoxy polymer solution, 146 g of cresol novolac type epoxy resin (epoxy equivalent: 198) as a polyfunctional epoxy resin, 78 g of phenol novolac (hydroxyl equivalent: 106) as a curing agent, and 2-ethyl-4methyl as a curing accelerator. Imidazole 0.7
After mixing 3 g and adding N, N-dimethylacetamide as a diluent solvent to make the solid content concentration 20%, the mixture was mechanically stirred for 1 h. Apply the obtained varnish on a glass plate,
Dry in a vacuum dryer at 100 ℃ / 1h under reduced pressure to a thickness of 25
A μm epoxy film was obtained. The epoxy film had a tensile strength of 65 MPa, a tensile elastic modulus of 2100 MPa, an elongation of 24%, a Tg of 78 ° C., a softening point of 90 ° C. and a thermal decomposition temperature of 380 ° C. When the epoxy film was sandwiched between copper foils having a thickness of 35 μm and molded under the conditions of 170 ° C./10 min and 1 MPa, the peeling strength of the copper foil was 1.6 kN / m. The Tg of the cured film was 130 ° C. Acetone, toluene, methylene chloride, 10% hydrochloric acid, 1
There was no abnormality even when immersed in 0% sodium hydroxide aqueous solution for 30 minutes.

Example 2 An epoxy film having a thickness of 28 μm was obtained in the same manner as in Example 1 except that 4.5 g of dicyandiamide was used instead of phenol novolac as the curing agent. Epoxy film has a tensile strength of 69 MPa and a tensile modulus of 19
00MPa, elongation 19%, Tg 71 ° C, softening point 83
C., and the thermal decomposition temperature was 351.degree. The copper foil peeling strength when formed in the same manner as in Example 1 was 1.9 kN / m. The Tg of the cured film was 137 ° C. The solvent resistance and chemical resistance were also good.

Example 3 Example 1 was repeated except that 3 g of 2-phenylimidazole was used instead of phenol novolac as the curing agent in Example 1.
An epoxy film having a thickness of 27 μm was obtained in the same manner as in.
The epoxy film had a tensile strength of 60 MPa, a tensile modulus of 1900 MPa, an elongation of 15%, a Tg of 77 ° C., a softening point of 80 ° C. and a thermal decomposition temperature of 363 ° C. The copper foil peeling strength when formed in the same manner as in Example 1 was 1.5 kN / m. The Tg of the cured film was 140 ° C. The solvent resistance and chemical resistance were also good.

Example 4 A high molecular weight epoxy polymer was synthesized in the same manner as in Example 1 except that the synthetic solvent N, N-dimethylacetamide in Example 1 was replaced with cyclohexanone. as a result,
The viscosity was saturated at 8,500 mPa.s, and the reaction was completed. The weight average molecular weight of the obtained high molecular weight epoxy polymer was 8 as measured by gel permeation chromatography.
9,000, the result measured by the light scattering method is 84,
It was 000. The reduced viscosity of dilute solution is 0.91dl
It was / g. An epoxy film having a thickness of 24 μm was obtained in the same manner as in Example 1 except that this high molecular weight epoxy polymer was used. The tensile strength of the epoxy film is 53MPa,
Tensile modulus is 1600MPa, elongation is 18%, Tg is 73
C., the softening point was 96.degree. C., and the thermal decomposition temperature was 383.degree.
The copper foil peeling strength when formed in the same manner as in Example 1 was 1.6 kN / m. The Tg of the cured film is 13
It was 7 ° C. The solvent resistance and chemical resistance were also good.

Example 5 A high-molecular-weight epoxy polymer was synthesized in the same manner as in Example 1 except that resorcinol was used instead of bisphenol A which is the bifunctional phenol in Example 1. As a result, the viscosity was saturated at 12,200 mPa.s and the reaction was completed. The weight average molecular weight of the obtained high molecular weight epoxy polymer was 228,000 as a result of measurement by gel permeation chromatography and 193,000 as a result of measurement by a light scattering method. The reduced viscosity of the diluted solution was 1.22 dl / g. An epoxy film having a thickness of 22 μm was obtained in the same manner as in Example 1 except that this high molecular weight epoxy polymer was used. Epoxy film has a tensile strength of 46 MPa, a tensile modulus of 1300 MPa, an elongation of 53%,
Tg is 68 ° C, softening point is 75 ° C, thermal decomposition temperature is 378 ° C
Met. The copper foil peeling strength when formed in the same manner as in Example 1 was 1.7 kN / m. T of cured film
The g was 110 ° C. The solvent resistance and chemical resistance were also good.

Example 6 Except that bisphenol A, which is a bifunctional phenol in Example 1, was replaced with 1,5-naphthalenediol.
A high molecular weight epoxy polymer was synthesized in the same manner as in Example 1. As a result, the viscosity was saturated at 18,300 mPa.s and the reaction was completed. The weight average molecular weight of the obtained high molecular weight epoxy polymer was 1,2030,000 as measured by gel permeation chromatography and 129000 as measured by light scattering method. The reduced viscosity of the diluted solution was 1.17 dl / g. An epoxy film having a thickness of 26 μm was obtained in the same manner as in Example 1 except that this high molecular weight epoxy polymer was used. Epoxy adhesive film has a tensile strength of 71MPa and a tensile modulus of 2500MPa.
a, elongation was 8%, Tg was 85 ° C, softening point was 98 ° C, and thermal decomposition temperature was 372 ° C. The copper foil peeling strength when formed in the same manner as in Example 1 was 1.5 kN / m. The Tg of the cured film was 154 ° C. The solvent resistance and chemical resistance were also good.

Example 7 An epoxy film having a thickness of 30 μm was obtained in the same manner as in Example 1 except that 50 g of tetrabromobisphenol A was added as a flame retardant to the composition of Example 1. Epoxy film has tensile strength of 52MPa and tensile modulus of 1500MPa
, Elongation was 12%, Tg was 74 ° C., softening point was 82 ° C., and thermal decomposition temperature was 352 ° C. The copper foil peeling strength when formed in the same manner as in Example 1 was 1.5 kN / m. The Tg of the cured film was 124 ° C. The solvent resistance and chemical resistance were also good. The flame resistance satisfied the standard V-0 according to UL94.

Example 8 A thickness of 28 μm was obtained in the same manner as in Example 1 except that 300 g of a brominated epoxy resin (epoxy equivalent of 400) which was a flame-retardant epoxy resin was blended in place of the cresol novolac type epoxy resin in Example 1. To obtain an epoxy film of. The epoxy film had a tensile strength of 55 MPa, a tensile modulus of 1600 MPa, an elongation of 17%, a Tg of 78 ° C., a softening point of 80 ° C. and a thermal decomposition temperature of 357 ° C. The copper foil peeling strength when formed in the same manner as in Example 1 is 1.5.
It was kN / m. The Tg of the cured film was 128 ° C. The solvent resistance and chemical resistance were also good. The flame resistance satisfied the standard V-0 according to UL94.

Comparative Example 1 The cresol novolac type epoxy resin in Example 1, the curing agent phenol novolac, and the curing accelerator 2-ethyl-4methylimidazole were not compounded.
An epoxy film having a thickness of 28 μm was obtained in the same manner as in Example 1. The tensile strength of the epoxy film is 75MPa, the tensile modulus is 1900MPa, the elongation is 25%, the Tg is 89 ° C,
The softening point was 98 ° C and the thermal decomposition temperature was 383 ° C. The copper foil peeling strength when formed in the same manner as in Example 1 is 0.
It was 4 kN / m. Tg of cured film is 101 ° C
Met. There was no abnormality when immersed in toluene, 10% hydrochloric acid, 10% aqueous sodium hydroxide solution, etc. for 30 minutes, but when immersed in methylene chloride or acetone, it swelled significantly.

Comparative Example 2 Phenoxy resin YP50 which is a high molecular weight epoxy polymer
The average molecular weight of P (Toto Kasei) was measured. Styrene equivalent weight average molecular weight by gel permeation chromatography is 6
8,000, the average molecular weight by light scattering was 58,000. The reduced viscosity of the diluted solution was 0.48 dl / g. The resin dissolved readily in methyl ethyl ketone.
The viscosity of a 20% solution of N, N-dimethylacetamide was 200 mPa.s. An epoxy adhesive film was obtained in the same manner as in Example 1 except that this high molecular weight epoxy polymer was used, but the thickness was 100 μm or less and the tensile strength was 1 or less.
No epoxy adhesive film of 0 MPa or more was obtained.

Comparative Example 3 Phenoxy resin Epon, which is a high molecular weight epoxy polymer
The average molecular weight of ol55L32 (shell) was measured. Styrene equivalent weight average molecular weight by gel permeation chromatography is 62,000, average molecular weight by light scattering is 5
It was 1,000. The reduced viscosity of the dilute solution is 0.4
It was 4 dl / g. The resin dissolved readily in methyl ethyl ketone. Also, N, N-dimethylacetamide 20%
The viscosity of the solution was 180 mPa.s. An epoxy film was obtained in the same manner as in Example 1 except that this high molecular weight epoxy polymer was used, but an epoxy film having a thickness of 100 μm or less and a tensile strength of 10 MPa or more could not be obtained.

Details of the test methods in the above Examples and Comparative Examples are shown below. Viscosity is EMD viscometer (Tokyo Keiki)
Was measured using. Gel Permeation Chromatography (GP
The column used for C) is TSkgelG6000 + G
It is 5000 + G4000 + G3000 + G2000. N, N-dimethylacetamide was used as the eluent, and the sample concentration was 2%. After the relationship between the molecular weight and the elution time was obtained using styrene having various molecular weights, the molecular weight was calculated from the elution time to obtain the styrene-equivalent weight average molecular weight. Light scattering altimeter is DLS-700 manufactured by Otsuka Electronics Co., Ltd.
Was used. The reduced viscosity of the diluted solution was measured using an Ubbelohde viscometer. Tensileon manufactured by Toyo Baldwin was used for the tensile strength, elongation, tensile modulus, and copper foil peeling strength. The film sample size was 50 × 10 mm and the pulling speed was 5 mm / min. The glass transition temperature (Tg) was measured using a 910 differential scanning calorimeter (DSC) manufactured by DuPont. The thermal decomposition temperature is the differential thermal balance TGD- manufactured by Vacuum Riko.
Using 3000, the weight loss onset temperature in air was taken as the thermal decomposition temperature.

As shown in each of the examples, by using the epoxy resin composition of the present invention, an epoxy adhesive having a thickness of 100 μm or less, which is excellent in heat resistance, chemical resistance and adhesiveness and has sufficient strength. A film can be made. As shown in Example 1, the epoxy film prepared using only the high molecular weight epoxy polymer had insufficient adhesion to the copper foil and solvent resistance. As shown in Comparative Examples 2 and 3, when a commercially available phenoxy resin, which is a high molecular weight epoxy polymer, was used, an epoxy adhesive film of 100 μm or less could not be formed.

[0036]

Example 9 Bisphenol A-type epoxy resin (epoxy equivalent: 177.5) as a bifunctional epoxy resin 17
7.5 g, bisphenol A as bifunctional phenols
(Hydroxyl equivalent: 115.5) 115.5 g and sodium hydroxide 1.77 g as an etherification catalyst were dissolved in cyclohexanone 547.9 g to make the solid content concentration in the reaction system 30%. While mechanically stirring this, keep the temperature in the reaction system at 120 ° C in an oil bath for 4 hours.
Held As a result, the viscosity was saturated at 19,700 mPa.s, and the reaction was completed. The weight average molecular weight of the obtained high molecular weight epoxy polymer was 89,000 as measured by gel permeation chromatography and 84,000 as measured by light scattering method. The reduced viscosity of the diluted solution was 0.91 dl / g. 1000 g of methanol to 100 g of the above high molecular weight epoxy polymer solution
Was added thereto to precipitate a high molecular weight epoxy polymer, which was air-dried to obtain 20 g of a high molecular weight epoxy polymer. 73 g of cresol novolac type epoxy resin (epoxy equivalent: 198) as a polyfunctional epoxy resin, 39 g of phenol novolac (hydroxyl equivalent: 106) as a curing agent, and 2-ethyl-4methyl as a curing accelerator were added to this high molecular weight epoxy polymer. 0.36 g of imidazole was added and mechanically stirred at 150 ° C. for 1 min to obtain an epoxy resin composition.

[0037]

Example 10 20 g of a high molecular weight epoxy polymer was obtained by precipitating a high molecular weight epoxy polymer and air-drying in the same manner as in Example 9 except that methanol was replaced with ethanol.

[0038]

Example 11 20 g of a high molecular weight epoxy polymer was obtained by precipitating a high molecular weight epoxy polymer and air-drying in the same manner as in Example 9 except that methanol was replaced with hexane.

[0039]

Example 12 In the same manner as in Example 9 except that acetone was used instead of methanol in Example 9, a high molecular weight epoxy polymer was deposited and air-dried to obtain 20 g of a high molecular weight epoxy polymer.

[0040]

Example 13 A high molecular weight epoxy polymer was synthesized in the same manner as in Example 1 except that cyclohexanone in Example 9 was replaced with N, N-dimethylacetamide which was an amide solvent. As a result, the viscosity was saturated at 19,700 mPa.s and the reaction was completed. The weight average molecular weight of the obtained high molecular weight epoxy polymer was 133,000 as measured by gel permeation chromatography and 129000 as measured by light scattering method. The reduced viscosity of the diluted solution was 1.08 dl / g. To 100 g of the above-mentioned high molecular weight epoxy polymer solution, 1000 g of methyl ethyl ketone was added to precipitate a high molecular weight epoxy polymer and air-dry to obtain 20 g of a high molecular weight epoxy polymer. 73 g of a cresol novolac type epoxy resin (epoxy equivalent: 198) as a polyfunctional epoxy resin and 39 g of phenol novolac (hydroxyl equivalent: 106) as a curing agent were added to the high molecular weight epoxy polymer.
0.36 g of 2-ethyl-4-methylimidazole was added as a curing accelerator, and the mixture was mechanically stirred at 150 ° C. for 1 minute to obtain an epoxy resin composition.

[0041]

Example 14 A cresol novolac type epoxy resin (epoxy equivalent: 19) as a polyfunctional epoxy resin was added to 100 g of the high molecular weight epoxy polymer solution in Example 13.
8) After dissolving 80 g, 1000 g of methanol was added to precipitate a high molecular weight epoxy polymer and air-dried to obtain 95 g. To this high molecular weight epoxy polymer, phenol novolac (hydroxyl group equivalent:
106) After compounding 39 g, mechanically at 150 ° C. for 1 h
It was stirred. Next, 0.36 g of 2-ethyl-4-methylimidazole was added as a curing accelerator, and the mixture was mechanically stirred at 150 ° C. for 1 min to obtain an epoxy resin composition.

[0042]

[Example 15] An epoxy resin was prepared by using 95 g of a high molecular weight epoxy polymer obtained by precipitating a high molecular weight epoxy polymer and air-drying the same as in Example 13 except that methanol was replaced with ethanol. A resin composition was obtained.

[0043]

[Example 16] An epoxy resin was prepared by using 95 g of a high molecular weight epoxy polymer obtained by precipitating a high molecular weight epoxy polymer and air-drying the same as in Example 13 except that hexane was used instead of methanol in Example 14. A resin composition was obtained.

[0044]

Example 17 A high molecular weight epoxy polymer was deposited in the same manner as in Example 13 except that methyl ethyl ketone was used instead of methanol in Example 14, and 95 g of the high molecular weight epoxy polymer obtained by air-drying was used to obtain an epoxy resin. A composition was obtained.

[0045]

Example 18 An epoxy resin composition was obtained in the same manner as in Example 9 except that 2.2 g of dicyandiamide was used in place of the phenol novolac as the curing agent.

[0046]

Comparative Example 4 An epoxy resin composition was obtained in the same manner as in Example 9 without blending the high molecular weight epoxy polymer in Example 9.

[0047]

Comparative Example 5 Phenoxy resin YP50 used in Comparative Example 2
P (Toto Kasei) 20g, cresol novolac type epoxy resin as polyfunctional epoxy resin (epoxy equivalent: 1
98) 73 g, phenol novolac (hydroxyl equivalent: 106) 39 g as a curing agent, and 2-ethyl-4methylimidazole 0.36 g as a curing accelerator were added, and an epoxy resin composition was obtained in the same manner as in Example 9.

[0048]

Comparative Example 6 An epoxy resin composition was obtained in the same manner as in Example 9 without blending the high molecular weight epoxy polymer in Example 13.

The above epoxy resin composition was heat-pressed and molded, and the obtained epoxy resin cured product was subjected to measurement of glass transition temperature (Tg) and thermal decomposition temperature (Td), tensile test and Charpy impact test. . 1 for the tensile test
The sample for Charpy test was put in a mold of 00 mm × 100 mm × 0.5 mm, and put in a mold of 100 mm × 100 mm × 1.5 mm, and molded under the conditions of 200 ° C./1 h and 2 MPa.

The test method is the same as that described above except for the Charpy impact test. A Charpy impact tester manufactured by Yonekura Seisakusho was used for the Charpy impact test. The sample size was 50 mm × 10 mm without a notch, and the anvil span was 20 mm.

The measurement results of each epoxy resin cured product are shown in Table 1.
Shown in. As shown in Examples 9 to 18, the system in which the high molecular weight epoxy polymer was blended, regardless of the curing system and the precipitation solvent, improved the tensile elongation and the Charpy impact value without lowering the Tg. Further, the tensile elongation and the Charpy impact value were improved even when compared with the system of Comparative Example 5 using a phenoxy resin as the high molecular weight epoxy polymer. Further, in a system using phenol novolac as a curing agent, an epoxy resin composition having a Tg of 180 ° C or higher and a thermal decomposition temperature of 380 ° C or higher could be obtained.

[0052]

[Table 1]

[Table 1] continued

[Table 1] continued

[Table 1] continued A system having two tan δ peaks showed a peak value on the high temperature side.

[0053]

As is apparent from the above description, according to the present invention, it becomes possible to provide an epoxy resin composition having a high Tg and excellent heat resistance, adhesiveness and impact resistance.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Shimizu             Hitachi Chemical, 1500 Ogawa, Shimodate City, Ibaraki Prefecture             Shimodate Research Institute, Industry Co., Ltd. (72) Inventor Masami Arai             Hitachi Chemical, 1500 Ogawa, Shimodate City, Ibaraki Prefecture             Shimodate Research Institute, Industry Co., Ltd.

Claims (10)

[Claims] 1. A compounding equivalent ratio of a bifunctional epoxy resin and a bifunctional phenol to a bifunctional epoxy resin and a bifunctional phenol is epoxy group / phenolic hydroxyl group = 1: 0.9-.
1.1, in the presence of a catalyst, the boiling point of 130 ℃ or more, in an amide-based or ketone-based solvent, the reaction solid content concentration 50 wt%
An epoxy resin composition comprising the following: a high-molecular-weight epoxy polymer obtained by heating and polymerizing the polyfunctional epoxy resin and a curing agent. 2. A styrene-equivalent weight average molecular weight measured by gel permeation chromatography of a high molecular weight epoxy polymer is 7
The epoxy resin composition according to claim 1, which has an amount of 50,000 or more. 3. The epoxy resin composition according to claim 1, wherein the high molecular weight epoxy polymer has an average molecular weight of 70,000 or more as determined by a light scattering method. 4. The epoxy resin composition according to claim 1, wherein the dilute solution of the high molecular weight epoxy polymer has a reduced viscosity of 0.70 dl / g or more. 5. The viscosity of a 20% solution of a high molecular weight epoxy polymer in an amide or ketone solvent has a viscosity of 1,000 mPa.s.
The epoxy resin composition according to claim 1, which is s or more. 6. A 20% solution of a high molecular weight epoxy resin in an amide or ketone solvent has a viscosity of 2,000 mPa.s.
The epoxy resin composition according to claim 1, which is the above. 7. The epoxy resin composition according to claim 1, wherein the solid content concentration at the time of synthesizing the high molecular weight epoxy polymer is 30% or less. 8. The epoxy resin according to claim 1, wherein the high molecular weight epoxy polymer is precipitated by adding a solvent which is a poor solvent for the epoxy polymer to a solution after completion of the polymerization reaction. Composition. 9. The epoxy resin composition according to claim 1, wherein the curing agent is selected from the group of polyfunctional phenols, amines and imidazole compounds. 10. The high molecular weight epoxy polymer is 100 μm.
The film-forming ability is such that a film having a tensile strength of 10 MPa or more can be formed with the following thickness.
10. The epoxy resin composition according to any one of 9 to 9.