JPS6173727A - Novel epoxy resin composition - Google Patents

Abstract

PURPOSE:A thermosetting epoxy resin composition which is excellent in workability and can give a cured product excellent in heat resistance, moisture resistance and mechanical properties, comprising an epoxy resin and an acid anhydride curing agent formed by mixing two tetrabasic acid anhydrides with each other. CONSTITUTION:A normally solid acid anhydride curing agent (B) is obtained by mixing 10-90wt% tetrabasic acid anhydride of formula I (wherein R1 is H or CH3, and R2 is H or a lower alkyl), obtained by an addition reaction between 1mol of a styrene monomer and 2mol of maleic anhydride with 90-10wt% tetrabasic acid anhydride of formula II (wherein R is R2), obtained by an addition reaction between 1 mol of tetrahydrophthalic anhydride compound and 1mol of maleic anhydride. An epoxy resin (A) (e.g., glycidyl ether- derived epoxy resin) having at least one epoxy group in the molecule is mixed with component B in an amount to provide 0.5-1.5 acid anhydride groups per epoxy group of component A.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a thermosetting epoxy resin composition containing a specific tetrabasic acid anhydride mixture as a curing agent component, and more particularly, to a thermosetting epoxy resin composition that has excellent workability, The present invention also relates to a thermosetting epoxy resin composition whose cured product has excellent heat resistance, moisture resistance, and mechanical properties.

(Prior art) Cured epoxy resins have been widely used in fields such as cast products, impregnated products, painted products, laminates, and adhesives for electrical and electronic products because of their good electrical and mechanical properties. has been done.

BACKGROUND ART In recent years, as the technology of electronic and electrical equipment and transportation equipment has become more sophisticated, the demand for materials that are heat resistant, have excellent mechanical properties, and have high moisture resistance is increasing year by year.

Among these required performances, the means to increase heat resistance are as follows:
It is known to increase the crosslink density of cured products. For this reason, a tetrabasic acid anhydride is used as a curing agent for the epoxy resin, but since the tetrabasic acid anhydride generally has a high melting point, the epoxy resin begins to partially cure during heating and melting, resulting in uniform curing. However, the compound represented by the general formula [I] which shows relatively good performance in this respect (for example, Japanese Patent Publication Nos. 44-2986 and 54-300)
No. 26, JP-A-57-188581, etc.) and compounds represented by the above general formula (IF) (e.g., JP-A-57-188581, etc.)
No. 9740, U.S. Pat. No. 4,371,688), it was still not sufficient.

Moreover, although the compound represented by the general formula CI) can provide a cured product with relatively excellent moisture resistance and mechanical properties, it has the disadvantage that the heat distortion temperature, which is one measure of heat resistance, is rather low. Although the compound represented by the general formula (IT) provides a cured product with excellent heat resistance, it has the drawback of poor moisture resistance and mechanical properties.

(Problems to be Solved by the Invention) Therefore, the present inventors conducted extensive studies to improve this drawback of the prior art, and found that by mixing the two types of tetrabasic acid anhydrides, a low melting point solution was obtained. It was discovered that a solid epoxy resin curing agent with good workability was obtained, and that cured products using the curing agent had excellent heat resistance, moisture resistance, and mechanical properties, and the invention was completed.

(Means for Solving the Problems) Thus, according to the present invention, (4) an epoxy resin and (B)
) Tetrabasic acid anhydrides 10 to 90 represented by the following general formula CD
M amount Q and the following general formula (tetrabasic acid anhydride 1 shown by ID
There is provided an epoxy resin composition characterized in that it contains an acid anhydride mixture that is solid at room temperature in an amount of 0 to 90% by weight.

The curing agent component in the present invention is composed of the tetrabasic acid anhydride represented by the above general formula [I] and the tetrabasic acid anhydride represented by the above general formula (If) ◎The first component is the general formula Tetrabasic acid anhydride hastyrene represented by [I], α
- 2 moles of maleic anhydride added to 1 mole of a styrenic monomer such as methylstyrene, vinyltoluene, isozolobenyltoluene, p-tert-butylstyrene, etc., and such tetrabasic acid anhydrides are known in the art. It can be easily obtained by reacting a styrene yarn with maleic anhydride in the presence or absence of a polymerization inhibitor or an inert solvent according to the method (for example, Japanese Patent Publication No. 44
-2986, 54-30026, etc.). Among these, adducts of α-methylstyrene are particularly prized for their excellent hygroscopicity.

On the other hand, the second component, the tetrabasic acid anhydride represented by the general formula (IF), is 3-methyl-△-7)7hydroanhydride7
Talic acid, 4-methyl-Δ-T tophhydrophthalic anhydride,
△ - 1 mole of maleic anhydride is added to 1 mole of a tetrahydrophthalic anhydride compound such as △-atophthalic anhydride, and such tetrabasic acid anhydride can be converted into a tetrahydrophthalic anhydride compound according to a known method. It can be easily obtained by reacting maleic anhydride (see, for example, Japanese Patent Publication No. 57-9740).

In addition to these, known curing agents such as tribasic acid anhydrides such as trimellitic anhydride and dibasic acid anhydrides such as methyltetrahydrophthalic anhydride may be added as long as the purpose of the present invention is not impaired. Good too.

In the present invention, the first component and the second component are comprised of 10 to 90% by weight, preferably 20 to 80% by weight, and 10 to 90% by weight, preferably 20 to 80% by weight of the latter.
used in a mixture of

Within this mixing ratio, the epoxy resin has a low melting point, good workability, provides a cured epoxy resin with sufficient heat resistance, and provides a synergistic improvement effect in moisture resistance and mechanical properties.

The method for mixing these two components may be selected as appropriate, and may be either a tri-blend method or a melt-mixing method.

One molecule of the resin used in the present invention is
It has more than one epoxy group, preferably 1.5 or more epoxy groups. Specific examples thereof include glycidi synthesized from bisphenol A and shrimp/'-rohydrin, ether-type epoxy resin, and phthalate. Glycidyl ester-type eddyalium resin synthesized from acid and evino-rohydrin, alicyclic epoxy resin obtained by epoxidizing alicyclic dienes such as cyclopentadiene and cyclohexadiene, unsaturated polymers such as I-liptadiene, and polyisoprene. Examples thereof include epoxidized products of polymers, and polymers or copolymers of unsaturated monooxides such as glycidyl methacrylate and allyl glycidyl ether. Of course, these are specific examples, and various polyhydric phenols can be used in place of bisphenol A, and other polybasic acids can be used in place of phthalic acid.

In the present invention, the mixing ratio of the acid anhydride curing agent and the epoxy resin is 0.5 to 1 acid anhydride group per epoxy group.
, 5 pieces, preferably 0.6 to 1.2 pieces, and if this usage ratio is too small or too large, the heat distortion temperature of the cured product tends to decrease.

When curing the composition of the present invention, it may be treated according to a conventional method, for example, at 50 to 250°C, preferably at 10°C.
A cured product is obtained by heating to 0 to 200°C. In this case, reaction accelerators such as tertiary amines, phenols, and imidazoles can be used.

Such epoxy resin compositions are mainly used in fields such as electrical insulation materials, structural materials, and adhesives, and in this case, reactive diluents, plasticizers, and inorganic substances such as talc, ceracola, alumina, and asbestos are added in accordance with conventional methods. fillers, pigments, flame retardants,
A mold release agent, an antifoaming agent, etc. can be added.

The present invention will be explained in more detail with reference to Examples below. Note that all parts and parts in Examples and Reference Examples are based on weight.

Reference Example 1 Maleic anhydride 196 in a Se-Gurasol flask with a stirrer
part (2 mol), 300 parts of toluene and 1 part of phenothiazine
After charging 0 part of α-methylstyrene and heating it to 60°C under a nitrogen atmosphere to uniformly dissolve it, add 118 parts (1 mol) of α-methylstyrene.
was added over 1 hour. Then, after heating to 115°C,
After the reaction was carried out for a period of time under a nitrogen atmosphere, the precipitated product was separated. The obtained product was recrystallized from methyl ethyl ketone to obtain 260 parts of a white solid product.

As a result of measuring the properties of the obtained product, the molecular weight was 3.
14, acid anhydride equivalent: 157, melting point: 197°C, c1
As a result of structural analysis based on 3-m, the above general formula [■
] Reference Example 2 3-Methyl-Δ-atophhydrophthalic anhydride was found to be a tetrabasic acid anhydride (hereinafter referred to as AMS-MA) in which R1 corresponds to a methyl group and R2 corresponds to hydrogen. 166 copies (
1 mol) and 196 parts (2 mol) of maleic anhydride were placed in a top-bottomed rubble flask equipped with a stirrer, and heated for 20 minutes under a nitrogen atmosphere.
React at 0°C for 4 hours.

Then, unreacted 3-methyl-Δ4-tetrahydrophthalic anhydride and maleic anhydride are recovered by simple distillation.

At this time, the distillation conditions are a final pressure of 10 Hg and a temperature of 200° C. in the pot.

Thereafter, 217 parts of methyl isobutyl ketone was added to 77.8 parts of the crude product remaining in the reaction vessel, dissolved at 110°C, and cooled to room temperature to obtain 44.5 parts of a white solid product.

As a result of measuring the properties of the obtained product, the molecular weight was 2.
64, acid anhydride equivalent 157, melting point 168°C, C1
As a result of structural analysis by 3-NMR, the general formula (
Tetrabasic acid anhydride (It) in which R3 corresponds to a methyl group (
It turned out to be MCTC (hereinafter referred to as MCTC).

Example 1 AMS-MAR and MCTC were melt-blended in the proportions shown in Table 1, and the melting point was measured by the capillary method.

The acid anhydride mixture thus obtained was added to Ebico) -1
004 (manufactured by Shell Co., Ltd., epoxy equivalent = 925) was mixed in a ratio of acid anhydride equivalent/epoxy equivalent -〇, 85, and then 100 parts of Epicoat-1004 was added with Keyazol 2PZ-CNS (manufactured by Shikoku Kasei Co., Ltd.) as a curing accelerator. Tri-blend was carried out at a ratio of 1 part to 1 part. This mixture was cured at 150°C for 4 hours to obtain a cured product with a thickness of 2 cm and a diameter of 50 mm.
The uniformity of the cured product was determined from the appearance of the cured product. In addition, the glass transition temperature and water absorption rate of this cured product in water production were investigated. The results are shown in Table 1.

This result shows that the acid anhydride mixture of the present invention has a low melting point and excellent workability, and that the epoxy resin cured product using this curing agent is uniform and has excellent heat resistance and water resistance.

Table 1 Example 2 Addition of Ebico-82 to the acid anhydride mixture obtained in Example 1
8 (manufactured by Shell Co., bisphenol A type I resin, epoxy equivalent = 190) in a ratio of acid anhydride equivalent/epoxy equivalent - 0.9, and 2-ethyl-4-methyl- as a curing accelerator. imidazole (epicor) -s
2B was added at a ratio of 0.1 part to 100 parts, and the mixture was cured at 150°C for 5 hours and then at 200°C for 10 hours, and the bending strength of the cured product was measured at 25°C and 150°C. .

The results are shown in Table 2.

This result shows that the cured epoxy resin using the acid anhydride mixture of the present invention has excellent bending strength not only at room temperature but also at a high temperature of 150°C.

Table 2

Claims (1)

[Claims] 1. (A) an epoxy resin and (B) the following general formula [I
] and 10 to 90% by weight of a tetrabasic acid anhydride represented by general formula [II].
A thermosetting epoxy resin composition comprising an acid anhydride curing agent that is solid at room temperature. ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[II] In the formula, R_1 represents hydrogen or a methyl group, R_2 represents hydrogen or a lower alkyl group, and R_3 represents Represents hydrogen or a lower alkyl group.