JPH01123818A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To provide an epoxy resin composition having excellent stability against moisture absorption and uniform physical characteristics, such as hue and heat resistance, of a cured product, by mixing an epoxy resin with a specified methyltetrahydrophthalic anhydride mixture liquid at room temperature. CONSTITUTION:A stereoisomer mixture is prepared by heating 4-methyl-DELTA<4>- tetrahydro-cis,cis-phthalic anhydride and/or cis-3-methyl-DELTA<4>-tetrahydro-cis,cis- phthalic anhydride in the presence of a stereoisomerization catalyst (e.g., dimethylaminoethanol). This stereoisomer mixture is heated in the presence of a structural isomerization catalyst (e.g., polyphosphoric acid), and the catalyst, etc. are removed from the reaction mixture by, e.g., distillation to produce an acid anhydride mixture liquid at room temperature. This mixture as a curing agent is added to an epoxy resin to produce an epoxy resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an epoxy resin composition that is cured by an epoxy resin and an acid anhydride containing a specific methyltetrahydrophthalic anhydride.

[Conventional technology]

Conventionally, methyltetrahydrophthalic anhydride (hereinafter abbreviated as M e -T HP A) has been used as a curing agent for epoxy resins.
Me-T HPA which is liquid at room temperature is well known and generally used, and is 4-methyl-Δ2-tetrahydro-cis,cis-phthalic anhydride. (hereinafter abbreviated as 4M e-Δ'-THPA) with sulfuric acid, phosphoric acid, BF, and complex.

AQCQ3. Structural isomer mixtures with different double bond positions within the cyclohexene ring are known, which are obtained by heating in the presence of an acid catalyst such as a cation exchange resin and causing a structural isomerization reaction (for example, U.S. Patent No. 2,959 , No. 599 specification). In this case, the isomer mixture is 4 M g-Δ'
-THPA and 4-methyl-Δ3-tetrahydro-cis,
Cis-phthalic anhydride.

It is a mixture with 4-methyl-Δ2-tetrahydro-cis,cis-phthalic anhydride and/or 4-methyl-Δ1-tetrahydro-cis,cis-phthalic anhydride.

Also, cis-3-methyl-Δ4-tetrahydro-cis,
Cis-phthalic anhydride (hereinafter referred to as cis-3Me-Δ'-T
It is known that an isomer mixture is obtained by heating HPA (abbreviated as HPA) in the presence or absence of a basic catalyst to cause a stereoisomerization reaction that does not involve movement of the double bond of the cyclohexene ring. The stereoisomer mixture is cis
-3M e-Δ4-THPA and trans-3-methyl-
It is a mixture of Δ4-tetrahydro-cis,cis-phthalic anhydride (hereinafter abbreviated as trans-3M e-Δ'-THPA), and is known to be liquid at room temperature (for example, JP-A-54-22499). Publication No.).

Furthermore, 4M e-Δ'-THPA and 3-methyl-Δ
The mixture with 4-tetrahydro-cis,cis-phthalic anhydride is structurally isomerized as described above (e.g.,
5-15495) or stereoisomerization (for example, JP-A-151941), methods of improving the liquid stability of isomer mixtures are known.

Furthermore, it is also known that a structural isomer mixture obtained by moving the double bond of M e -T HP A can be liquefied by heat treatment in the presence of a stereoisomerization catalyst (
For example, Japanese Patent Application Laid-Open No. 55-89277).

[Problem that the invention seeks to solve]

However, the isomer mixture obtained by the structural isomerization reaction described above has poor moisture absorption stability after being mixed with an epoxy resin, and has the disadvantage that crystals precipitate or become cloudy due to moisture absorption.

In addition, although the isomer mixture obtained by stereoisomerization reaction has excellent moisture absorption stability after mixing with epoxy resin, the isomer mixture obtained by structural isomerization reaction is colorless to pale yellow. However, the epoxy resin has a yellow to brown color, which not only lowers the commercial value but also deteriorates the hue of the cured epoxy resin product. Further, for example, the isomer mixture obtained by stereoisomerizing the structural isomer mixture shown in JP-A-55-89277 is yellow to brown, and the starting material M e -T HP
Composition of A (4Ma-Δ'-THPA and cis-3M
Depending on the mixing ratio of e -Δ'-THPA), the hue of the cured epoxy resin product is uneven, and when you cut the cured product and look inside, the central part appears reddish, and the physical properties of the cured product are partially different. There was a problem.

The present invention is directed to M e -T HP A which is a pale liquid at room temperature.
The object of the present invention is to provide an epoxy resin composition containing the following: an epoxy compound having excellent moisture absorption stability and a cured epoxy product having a uniform hue.

[Means for solving problems]

The present invention provides (A) epoxy resin and (B) 4Me-Δ
'-THPA and/or cis-3Me-Δ4-TH
The present invention relates to an epoxy resin composition containing an acid anhydride mixture that is obtained by heat-treating a PA stereoisomer mixture in the presence of a structural isomerization catalyst and is liquid at room temperature.

In the present invention, the epoxy resin is a compound having two or more epoxy groups in the molecule, such as bisphenol A
1,4-butanediol and other polyhydric alcohols, and phthalic acid.

Polyglycidyl esters of polybasic acids such as hexahydrophthalic acid, N-glycidyl derivatives of compounds with amines, amides or heterocyclic nitrogen bases, (3',4'-epoxycyclohexylmethyl)-3,4-epoxycyclohexane Examples include alicyclic epoxy resins such as carboxylates.

The acid anhydride mixture in the present invention can be obtained as follows.

4 M e-Δ'-THPA, cis-3Me-Δ4
-T) (PA or a mixture thereof is first heated in the presence or absence of a stereoisomerization catalyst to obtain a stereoisomer mixture. It is then heated in the presence of a structural isomerization catalyst. This sequence is If the mixture is reversed, it is not possible to obtain an acid anhydride mixture that achieves the object of the present invention. ``A basic catalyst is used as the stereoisomerization catalyst, and for example, a basic catalyst is used as a stereoisomerization catalyst. Hydroxide, oxide, alcoholade, phenolate, etc., N,
N-dibutylaniline, N.

Examples include tertiary amines such as N-diethylaniline and dimethylaminoethanol, and quaternary ammonium salts such as triethylbenzylammonium chloride.

Examples of structural isomerization catalysts include sulfuric acid and phosphoric acid.

Polyphosphoric acid, para-toluenesulfonic acid, BF, -etherate, BF, -phenolate, AQCQ.

TiCQ4. Acidic catalysts such as ZnCQ and t-cation exchange resins are used. In addition, catalysts that simultaneously perform structural isomerization and disproportionation, such as palladium catalysts or ruthenium catalysts, are known (U.S. Pat. No. 2,764,597), but these catalysts also have the structure of the present invention. Included in isomerization catalysts.

4 M e-Δ'-THPA and/or cis-3
By heating M e-Δ'-THPA in the presence or absence of a stereoisomerization catalyst, stereoisomerization occurs, resulting in an acid anhydride mixture (stereoisomer mixture) having a lower melting point than the raw material.

4 M e-8'-THPA stereoisomer is 4
-Methyl-Δ4-tetrahydrosis, trans-phthalic anhydride is considered, and cis-3M e-Δ4-TH
As a stereoisomer of PA, trans -3M e-
Δ'-THPA, cis-3-methyl-Δ4-tetrahydrosis, trans-phthalic anhydride and trans-3-
Methyl-Δ4-tetrahydrosis.

Trans-phthalic anhydride is considered.

4 M e-Δ'-THPA and/or cis-3
Acid anhydride mixture obtained by heat treatment of Me-8''-THPA in the presence or absence of a stereoisomerization catalyst (
When a stereoisomer mixture) is heated in the presence of a structural isomerization catalyst, at least a portion of the acid anhydride contained in the acid anhydride mixture moves the double bonds in its structure and becomes a structural isomer. The number of isomers increases, resulting in an acid anhydride mixture with a lower melting point. The melting point of the finally obtained acid anhydride mixture is adjusted so that it is liquid at room temperature at most.

Heating in the presence of a stereoisomerization catalyst or a structural isomerization catalyst is preferably carried out at 100 to 250°C, particularly at 15°C.
Preferably, the reaction is carried out at a temperature of 0 to 200°C. Heating in the absence of a stereoisomerization catalyst is preferably carried out at 150 to 250°C, particularly preferably 180 to 230°C.

If this temperature is too low, the heat treatment will be insufficient and sufficient isomerization will not occur, and if this temperature is too high, high molecular weight by-products will be likely to be produced.

Moreover, the stereoisomerization catalyst and the structural isomerization catalyst each have 4
Me-Δ'-THPA, cis-3Me-Δ'
-0.05 to 5 for THPA or mixtures thereof
Preferably, % by weight is used. If this amount is too small, the heat treatment time will be long, and if this amount is too large, high molecular weight by-products will be likely to be produced.

Further, heating in the presence of a stereoisomerization catalyst or a structural isomerization catalyst may be carried out for usually 0.5 to 20 hours, preferably 3 to 10 hours in any case.

After heating, the acid anhydride mixture (stereoisomer mixture) obtained by heating in the presence or absence of a stereoisomerization catalyst or by distillation etc. After separating the organisms, they are subjected to heating in the presence of a structural isomerization catalyst.

After heating, the acid anhydride mixture obtained by heating in the presence of a structural isomerization catalyst is used as the acid anhydride mixture, which is component (B) of the present invention, after removing the catalyst etc. by distillation etc. Ru.

The acid anhydride mixture which is the component (B) of the present invention is composed of the raw materials 4Me-Δ'-THPA and cis-3Me-Δ
'-It may be obtained by allowing an alicyclic dicarboxylic acid anhydride, aromatic dicarboxylic acid anhydride, etc. other than THPA to be present from the beginning or during the production, or by adding them after the completion of the reaction. It can be anything. Examples of such dicarboxylic anhydrides include tetrahydrophthalic anhydride, 3
, 6-nindomethylenetetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phthalic anhydride, and the like. Such operations are carried out within the range consistent with the purpose of the present invention.

4M e-Δ'-THPA and cis-3M e which are the raw materials for the acid anhydride mixture which is the component (B) of the present invention
-Δ'-THPA is blended in any proportion, but from the viewpoint of moisture absorption stability of the epoxy resin composition and coloring of the composition, 4 M e-Δ'-THPALOO to 20% by weight.
It is particularly preferable to mix the amount of cis-3Me-Δ'-THPAO to 80% by weight.

In the present invention, the epoxy resin as the component (A) and the acid anhydride mixture as the component (B) are mixed in an appropriate ratio, but the ratio of the acid anhydride group to 1 equivalent of the epoxy group is 0.8 to 1 equivalent. It is preferable to mix them so that

A curing accelerator can be added to the epoxy resin composition according to the present invention. As a curing accelerator, 2-ethyl-4-methylimidazole and cyanoethyl-2-ethyl-4-methylimidazole are used.

1-Benzyl 2-methylimidazole, 1-methylimidazole, 1,2-dimethylimidazole.

Benzyldimethylamine, N,N-dimethylaniline,
Tris(dimethylaminomethyl)phenol, 1,8-
Tertiary amines such as diazabicyclo(5,4,O)undecene-7, tertiary amine salts of such tertiary amines such as 2-ethylhexanoate, phenol salt, oleate, formate, acetate.

Quaternary ammonium salts such as tetramethylammonium chloride and benzyltriethylammonium chloride;
Examples include metal salts such as tin octylate, zinc octylate, sodium methoxide, and metal acetylacetone complex salts of metals such as cobalt and nickel. The curing accelerator is preferably used in an amount of 0.1 to 8% by weight, particularly preferably 0.3 to 5% by weight, based on the epoxy resin as component (A).

Reactive diluents, plasticizers, fillers, dyes, flame retardants, and the like can be added as appropriate to the epoxy resin composition according to the present invention.

〔Example〕

Next, examples of the present invention will be shown. Hereinafter, parts and % mean parts by weight and % by weight, respectively, unless otherwise specified.

Examples 1 to 5 (1) Production of acid anhydride mixture 4Me-Δ' was added to an IQ four-loop flask at the ratio shown in Table 1.
-THPA (melting point 64℃) and cis-3Me -Δ
100 parts of -THPA (melting point 61°C) was mixed with 1 part of dimethylaminoethanol, and the mixture was heated and stirred at 170°C for 3 hours.

observed the phase. In addition, the hygroscopic stability of the epoxy resin composition, the coloring test and melting point of the cured epoxy resin or -
The number of days of crystallization was measured at 15°C. These results are shown in Table 1.

Furthermore, 2.5 parts of polyphosphoric acid was added to the remaining reaction solution, and 1
Structural isomerization was performed by heating and stirring at 70°C for 5 hours. This reaction solution was distilled under reduced pressure at 3 mmHg to obtain an acid anhydride mixture.
Nine hues were observed at room temperature.

Additionally, the hygroscopic stability of the epoxy resin compositions described below.

The cured epoxy resin product was subjected to a coloring test and a measurement of the number of days of crystallization at -15°C. These results are shown in Table 1.

(2) Moisture absorption stability test of epoxy resin composition 80 parts of epoxy resin (Epicote 828, trade name of Yuka/Shell Epoxy Co., Ltd.), epoxy resin (Araldite DYO2)
2. Take 20g of a mixture of 20 parts of Ciba Geigy (trade name) and 100 parts of the above acid anhydride mixture into a 50m2 beaker and leave it in a constant temperature and humidity chamber kept at 40°C and 90% RH for 24 hours. The presence or absence of crystal precipitation and white turbidity was then visually observed.

The evaluation was rated as Δ when there was no precipitation of crystals and no cloudiness, Δ when there was a slight precipitation of O1 crystals along the beaker wall, and X when precipitation of crystals spread on the liquid surface and there was cloudiness.

(3) Coloring test of cured epoxy resin 80 parts of epoxy resin (Epicoat 828), 20 parts of brominated epoxy resin (BROC1 Nippon Kayaku Nipponka parts name),
5 parts of titanium white and 3 parts of Erosil (trade name, manufactured by Nippon Aerosil Co., Ltd.) were mixed in a mortar to form a solution A.

A mixture of 100 parts of the above acid anhydride mixture and 2 parts of cyanoethyl-2-ethyl-4-methyl-imidazole (2 parts 4MZ-CN, trade name of Shikoku Kasei Co., Ltd., curing accelerator) is used as liquid B.

A composition was obtained by mixing 108 parts of Solution A and 60 parts of Solution B, and 30 g of the composition was weighed into a pudding cup.

After curing by heating at 80° C. for 3 hours and then at 105° C. for 3 hours, the cured product was taken out from the pudding cup, cut in half, and the color of the cross section was visually observed.

O1: Colorless to light yellow with a uniform hue.
If the central part is slightly reddish and the surrounding area is pale yellow, and the hue is uneven, it is called Δ.If the central part is obviously reddish and the surrounding area is pale yellow, and the hue is uneven, it is called X. evaluated.

(4) Measurement of crystallization days at -15℃ Place the acid anhydride mixture in a test tube with a diameter of 10 mm and a height of 10c+a for about 8 minutes, then seal it tightly and place it in a constant temperature bath set at -15℃. The number of days until crystals started to precipitate was investigated.

Comparative Examples 1 to 5 (1) Production of acid anhydride mixture 4Me-Δ' was added to an IQ four-loaf flask at the ratio shown in Table 2.
-THPA (melting point 64℃) and cis-3Me -Δ
'-THPA (melting point: 61°C) was taken in a total of 1000 parts, 3 parts of polyphosphoric acid was added thereto, and the mixture was heated and stirred at 170°C for 5 hours.

500 g was taken out from the reaction solution and distilled under reduced pressure at 3 mmHg to obtain a mixture of structural isomers, which had properties at room temperature.

Ill guessed the hue.

In addition, the epoxy resin composition was subjected to a moisture absorption stability test, a coloring test of a cured epoxy resin product, and a measurement of the melting point or the number of days of crystallization at -15°C. These results are shown in Table 2.

Add 2.5 ml of dimethylaminoethanol to the remaining reaction solution.
of the mixture was heated and stirred at 170° C. for 3 hours to effect stereoisomerization.

This reaction solution was distilled under reduced pressure at 31111 Hg to obtain an acid anhydride mixture, which was observed to have two hues at room temperature. Furthermore, the epoxy resin composition was subjected to a moisture absorption stability test, a coloring test of a cured epoxy resin product, and a measurement of the number of days of crystallization at -15°C. These results are shown in Table 2.

(2) The moisture absorption stability test of the epoxy resin composition and the coloring test of the cured epoxy resin product were conducted in the same manner as in Examples 1 to 5. [Effects of the Invention] The epoxy resin composition according to the present invention has excellent moisture absorption stability, and the acid anhydride mixture contained in the composition is liquid and light-colored at room temperature. This is favorable for adjustment.

Claims (1)

[Claims] 1. (A) Epoxy resin and (B) 4-methyl-Δ^4-tetrahydro-cis, cis-phthalic anhydride and/or cis-3-methyl-Δ^4-
An epoxy resin composition containing an acid anhydride mixture that is obtained by heat-treating a stereoisomer mixture of tetrahydro-cis, cis-phthalic anhydride in the presence of a structural isomerization catalyst and is liquid at room temperature.