JPS61108624A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:The titled lowly viscous, low-temperature curable composition which can form a cured product of excellent heat resistance, prepared by mixing a specified epoxy resin with pyromellitic anhydride. CONSTITUTION:A polyglycidylamino compound of the formula (wherein R is phenylene or cyclohexylene), e.g., N,N,N',N'-tetraglycidyl-m-xylylenediamine, and an epoxycyclohexyl group-containing alicyclic epoxy resin (e.g., 3,4- epoxycyclohexyl 3,4-epoxycyclohexanecarboxylate) are used. Namely, a mixture of 20-80wt% said polyglycidylamino compound and 80-20wt% said alicyclic epoxy resin is mixed with pyromellitic anhydride in an amount to provide about 0.6-1.2 equivalent of the anhydride groups per equivalent of the epoxy groups.

Description

[Detailed description of the invention] [Industrial application field] The present invention has low viscosity, excellent curability at low temperatures, and
The present invention relates to an epoxy resin composition that can provide a cured product with excellent mechanical properties, adhesive properties, electrical insulation properties, moisture resistance, and other properties.

[Conventional technology]

In recent years, there has been an increasing demand for high-performance epoxy resin compositions that can be applied to aerospace structural materials, electrical insulation materials, and the like.

In the aerospace industry, epoxy resin compositions with good mechanical properties and adhesive properties are used as matrix for fiber reinforced composite materials. However, currently 170
Due to the need for a high curing temperature of ~180°C, there are various economic and technical problems, such as large amounts of equipment and equipment, large manufacturing costs, large internal stress in the cured product, and difficulty in outdoor repair work of composite material structures. There is a problem with this. In addition, when molding fiber-reinforced composite materials by the filament winding method or pultrusion method, the epoxy resin used as the base material is limited to a level that allows easy removal of air bubbles brought in by the fiber bundles when impregnating the fiber bundles with resin. A necessary condition is that the viscosity is low.

In order to solve the above problems, it is desired to develop an epoxy resin composition that has low viscosity, cures at low temperatures, and has high heat resistance.

In addition, in recent years, in the electrical and electronic industries, the use of high-performance polymer materials as insulating materials has gradually met various demands for smaller, lighter equipment, higher reliability, and longer lifespans. However, recently there has been a strong demand for improvements in heat deterioration resistance as the operating temperature of equipment rises and moisture deterioration resistance as equipment installation locations become more diverse. On the other hand, the functions of integrated circuits, transistors, diodes, and other elements are becoming increasingly sophisticated, and
Due to the demand for high reliability of parts, conventional technology for sealing semiconductor elements: c
) Problem score is 8. vinegar. However, in conventional epoxy resin semiconductor encapsulation, the curing reaction progresses to an appropriate point, the solidified epoxy resin is turned into powder, and then molded into a tablet. This is done by putting it in a cylinder, heating it to melt it at a high temperature, injecting it under pressure into a heated mold, and heating it to harden it.

However, this method has complicated steps up to tablet molding and requires a long time for heating and melting, resulting in decreased productivity and increased product costs.

Furthermore, when encapsulating semiconductor elements, resin usage efficiency is poor due to high-pressure molding, requiring the use of expensive mold clamping presses and high-pressure resistant molds, and in addition, semiconductor elements are hardened at high temperatures. Deformation, misalignment, or disconnection of wiring and bonding wires often occur, leading to problems such as high capital investment and a decline in product characteristics and product yield.

Are there any problems like this when using liquid, low-viscosity epoxy resin compositions to encapsulate semiconductors? If you use it, cast molding becomes possible and all problems can be solved.

[Problem that the invention seeks to solve]

The various economic and technical problems associated with the utilization of high-performance epoxy resin materials in the aerospace and electrical and electronic industries as mentioned above are all due to their low viscosity and ability to cure at low temperatures. Moreover, it is expected that this problem can be solved by developing an epoxy resin that provides a cured product with high heat resistance. An object of the present invention is to provide an epoxy resin composition that can meet such expectations.

Many attempts to provide highly heat-resistant epoxy resin compositions have already been proposed, but one useful method is to blend an aromatic polycarboxylic acid anhydride such as pyromellitic anhydride as a curing agent. It is. However, aromatic polycarboxylic acid anhydrides are difficult to dissolve in ordinary epoxy resins, and the viscosity of the mixture after mixing the base resin and curing agent is high, and furthermore, the reactivity with ordinary epoxy resins is low at low temperatures. The need for low and high curing temperatures has been said to be a major drawback. If unreacted aromatic polycarboxylic acid hydroxide remains in the cured product, it will cause a decrease in the moisture resistance of the cured product, so it is technically difficult to select the curing conditions. This is one of the obstacles.

[Means for solving problems]

As a result of intensive research aimed at improving the drawbacks of the prior art as described above, the present inventors found that when pyromellitic anhydride is mixed with a specific epoxy resin, the two are uniformly dissolved, have low viscosity, and have excellent low-temperature curing properties. , and that the cured product thereof can be made into an epoxy resin composition having good heat resistance, vibration characteristics, adhesion, electrical properties, and moisture resistance, and the present invention has been completed.

That is, the present invention provides the following general formula (I)...
......(I) [Wherein, R represents a phenylene group or a cyclohexylene group. ] This is an epoxy resin composition comprising a polyglycidylamino compound represented by the following, an alicyclic epoxy resin having one or more epoxycyclohexyl groups in one molecule, and pyromellitic anhydride.

The epoxy resin composition obtained here is a low-viscosity liquid composition in which pyromellitic anhydride is uniformly dissolved, and this composition is poured into a mold and heated at a low temperature of 90°C for 6 hours. It provides a cured product with excellent properties such as heat resistance, mechanical properties, electrical insulation, and moisture resistance. It can be seen that the low curing temperature of 90°C is extremely low compared to the conventional curing of epoxy resins with acid anhydrides, which is carried out at high temperatures of 170 to 180°C.

Thus, by using the composition of the present invention, many advantages are achieved, such as improved workability, reduced manufacturing costs, reduced equipment requirements, and reduced internal stress in the cured product.

The polyglycidylamino compound used in the present invention refers to a compound represented by the general formula CI). These compounds are polyfunctional compounds, contribute to providing a cured product with high heat resistance, and have a
It has an extremely low viscosity of 0 to 15 poise. Furthermore, since these compounds have two tertiary amino groups in their molecules, they have high curing reactivity and can smoothly cure the composition of the present invention even without the use of a curing accelerator. .

Specific examples include N, N.

Mention may be made of N',N'-tetraglycidyl metaxylylene diamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, which compounds are commercially available from Mitsubishi Gas, for example under the trade name "Tetralad". It is sold by Kagaku Co., Ltd. and is easily available on the market.

Next, the alicyclic epoxy resin used in the composition of the present invention has 1 epoxycyclohexyl group in one molecule.
It refers to substances included in the concept of so-called epoxy resins having cyclohexene groups, and these substances can be produced, for example, by reacting a raw material having a cyclohexene group with a peroxide. The alicyclic epoxy resin specifically has t! ,3
．． 4-Epoxycyclohexy/L/-3,4-epoxycyclohexanecarboxylate, vinylcyclohexene dioxide, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-xt, *C6-methylcyclohexanecarboxy It contains compounds such as ester, bis(3,4-epoxycyclohexyl) adipate, etc. as main components.

In the composition of the present invention, the polyglycidylamino compound is blended in a proportion ranging from 20 to 80% by weight, and the cycloaliphatic epoxy resin is blended in a proportion ranging from 80 to 20% by weight. When the blending amount of the alicyclic epoxy resin exceeds 20% by weight, the rate of viscosity increase after mixing the base resin and the curing agent is fast;
When the concentration exceeds 80%, the solubility of pyromellitic anhydride, which is a curing agent, decreases, and as a result, desired properties cannot be imparted to the cured product.

The amount of pyromellitic anhydride in the composition of the present invention is usually 0.6 to 1.
It is desirable to select an amount within a range that corresponds to 2 equivalents, but
There is no problem even if the ratio of the foot is outside this range, if necessary.

Pyromellitic anhydride can also be used in combination, for example, by replacing a part of it with a liquid acid anhydride, as long as the heat resistance is not significantly impaired. Examples of such acid anhydride compounds include methylhexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylnadic anhydride.

Other epoxy compounds, diluents, reactive diluents, etc. may be appropriately selected and blended into the composition of the present invention as long as they do not impair the purpose of the present invention.

Other epoxy compounds include bisphenol A diglycidyl ether type epoxy resin, bisphenol F diglycidyl ether type epoxy resin, novolak type epoxy resin, glycerin glycidyl ether type epoxy resin, polyglycol diglycidyl ether type epoxy resin, and glycidyl ester type epoxy resin. These include resins, glycidylamine type epoxy resins, halogenated bisphenol A diglycidyl ether type epoxy resins, etc.

In the epoxy resin composition of the present invention, as described above, the effect of the tertiary amino group in the polyglycidylamino compound molecule is
Therefore, curing can proceed even without the use of a curing accelerator, but there is no problem in using a curing accelerator if necessary.

The composition of the present invention may optionally include fiber reinforcing materials such as inorganic fibers such as glass am, gypsum fiber, carbon fiber, silicon carbide fiber, and alumina fiber, and heat-resistant organic fibers such as aromatic polyamide; silica; Inorganic fillers such as alumina, mica, calcium carbonate, clay, perlite, and shirasu balloons: mold release agents, surface treatment agents, colorants, etc.
A seed additive may also be added and provided.

The epoxy resin composition of the present invention has low viscosity, excellent curability at low temperatures, high heat resistance, mechanical properties, adhesive properties,
Since it can provide a cured product with excellent electrical insulation and moisture resistance, it is suitably used in various applications such as matrix resins for fiber-reinforced composite materials and semiconductor encapsulation materials for cast molding.

〔Example〕

The present invention will be specifically explained below using examples. In the examples, unless otherwise specified, the number of parts blended is based on weight.

Example 1 46 parts of pyromellitic anhydride and methylnadic anhydride
69 parts of N, N, N1. °
N1-tetraglycidyl metaxylylene diamine (trade name rTETRAD-YJ manufactured by Mitsubishi Gas Chemical Co., Ltd.)
70 parts and 3,4-epoxycyclohexyl-3,4-
Add 50 parts of epoxycyclohexane carboxylate (trade name: Celoxide 2021J, manufactured by Daicel Chemical Industries, Ltd.), thoroughly knead with a roll to defoam, pour into a mold, and heat at 90°C for 6 hours. A sheet-like cured product with a thickness of about 3 u was obtained.

The resulting mixture before curing! The viscosity of the product and the properties and physical properties of the cured product are shown in Table 1, the electrical properties of the cured product are shown in Table 2, and Table 3
2 shows the moisture resistance of the cured product.

Example 2 56 parts of pyromellitic anhydride and methylnadic anhydride
84 parts of N, N, N'
, N'-tetraglycidylmethaxylylenediamine (
Product name rTETRAD-YJ.

(manufactured by Mitsubishi Gas Chemical Co., Ltd.) 70 parts and vinylcyclohexene dioxide (trade name rERL-4206J, UN
Made by ION CARBIDE CORPORATION)
30 parts and thoroughly kneaded with a roll to defoam,
The mixture was poured into a mold and heated at 90° C. for 6 hours to obtain a cured sheet approximately 5 mm thick.

The various performances of the obtained kneaded product before curing and the cured product are also listed in Tables 1 and 2.

〔effect〕

As is clear from the results of the examples, the epoxy resin composition of the present invention has good solubility of pyromellitic anhydride at low temperatures, low viscosity, high curing reactivity at low temperatures, and is transparent and has extremely high heat resistance. It can be seen that a cured product having a deformation temperature is obtained. Furthermore, the electrical properties have no temperature dependence, indicating that the cured product has high heat resistance, and it can be evaluated that there is virtually no deterioration of the electrical properties due to water absorption. It turns out that they have excellent sex.

Claims (1)

[Claims] 20 to 80% by weight of a polyglycidylamino compound represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R is a phenylene group or a cyclohexylene group) and an epoxycyclohexyl group An epoxy resin composition prepared by blending pyromellitic anhydride with a mixture of 80 to 20% by weight of an alicyclic epoxy resin having one or more of the following in one molecule.