JPH03275710A - Curable epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition useful as insulating material of electrical and electronic parts, having excellent mechanical strength and small internal stress without damaging moldability such as flowability, burr properties and stain of mold, comprising an epoxy resin, phenol resin and specific silicone- modified epoxy resin. CONSTITUTION:The objective composition comprising 100 pts.wt. an epoxy resin (e.g. bisphenol A diglycidyl ether), 0-100 pts.wt., preferably 1-80 pts.wt. phenol resin (e.g. phenol novolak resin) and 1-100 pts.wt., preferably 5-50 pts.wt. silicone-modified epoxy resin prepared by reacting an amino modified silicone containing an amino group only at one end of polysiloxane chain with an epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a curable epoxy resin composition, and more specifically, it has excellent mechanical strength, low internal stress (and has excellent fluidity, flakiness, mold staining, etc.). The present invention relates to a curable epoxy resin composition that does not impair moldability, and is particularly useful as an insulating material for electrical and electronic parts.

[Prior art] A cured product of an epoxy matrix composition has dielectric properties, volume resistance
Because of its excellent electrical properties such as insulation vlFJJ strength, and mechanical properties such as bending strength, compression strength, and impact strength, it is used as an insulating material for various electrical and electronic parts such as transfer molding, injection molding, and packaging. It is widely used in methods such as coating, casting, powder coating, dipping, and dripping.

Electrical and electronic parts are smaller! We are in the era of IJT, and even though the chips of IC components are becoming larger due to the increase in the degree of integration, packages are required to be smaller and thinner.

Furthermore, in order to save space, so-called surface mounting, in which IC components are mounted directly onto a printed circuit board, has become popular. This method has caused various problems including package cracks because the small 1T (i-type) IC components are directly exposed to the high temperature of the solder bath.

For this reason, it has become necessary to increase the strength of the package.1. One method is to increase the blending ratio of silica in the epoxy resin composition.

In addition, curable epoxy resins generate internal stress due to mold shrinkage and temperature changes during curing, which causes problems such as damage to electronic components and cracks in packages during heating and cooling cycles. In order to improve this, it is common practice to add an elastomer to the epoxy resin as a stress relaxation agent.

In either case, the viscosity of the epoxy resin composition itself increases and its fluidity tends to deteriorate. As a result, the problem of poor filling properties into molds and the like and reduced productivity has become apparent. Furthermore, when an oily substance is blended, flakes and mold stains occur, which also causes a problem of reduced productivity. For this,
There is a need for a curable epoxy resin composition that has excellent mechanical properties, low internal stress, and excellent moldability.

Here, we will discuss the current state of stress relaxation agents in more detail.

First, they can be broadly classified into organic and silicone-based elastomers, and butadiene-based polymers such as CTBN and CTB are typical examples of organic elastomers.

However, silicone elastomers have recently become mainstream in the modification of IC encapsulating materials due to their heat resistance, moisture resistance, electrical properties, and the like. The silicone used is organically modified silicone oil or fine silicone powder in which organic functional groups are introduced into the side chains or terminals of siloxane. There are already numerous patent applications regarding their use. They can be broadly classified as follows.

(1) A method of adding organically modified silicone oil to a composition as it is (see Japanese Patent Application Laid-Open No. 1983-69244).

(2) A method of blending a curable silicone composition and curing the silicone when curing the epoxy resin composition (
(See Japanese Patent Application Laid-Open No. 1-126381).

(3) A method of blending a copolymer obtained by pre-reacting an organically modified silicone and an organic polymer into an epoxy resin composition (
(See Japanese Unexamined Patent Publication No. 58-21417).

(4) A method of blending silicone pre-cured into powder form into an epoxy resin composition (JP-A-58-2
(See Publication No. 19218).

Among the above-mentioned methods, the method using oil has problems with the generation of flakes, mold stains, and stains on the surface of the molded product, while the method using copolymers and powders has problems with the fluidity of the resin composition. Due to the low concentration, filling properties into molds etc. are poor, and in both cases, a decrease in productivity is a problem.

Particularly when blending silicone copolymers, siloxanes having functional groups in side chains or at both ends have been used. Reactions between these and polyfunctional organic polymers often involve crosslinking reactions and chain polymerization, making it difficult to control the degree of reaction and making it difficult to obtain copolymers with stable properties. Among these, those having an amino functional group have high reactivity, so it is difficult to control the reaction, and property fluctuations over time after MC conversion are also a problem. Furthermore, they generally have a problem of poor mold releasability.

In addition, most of the obtained copolymers have a crosslinked structure rubber 17
Epoxy resin compositions containing this as a stress relaxation agent have low fluidity and therefore have poor filling properties into molds, resulting in a significant drop in productivity.

[Problems to be solved by the invention] As mentioned above, epoxy resin sealing materials designed to have excellent mechanical strength and low internal stress have poor moldability such as fluidity, flakiness, and mold staining. There are various problems such as poor performance. The inventors of the present invention have conducted extensive research on stress relaxation agents to be added to epoxy resins, and have found that if a specific silicone-modified epoxy resin is added to an epoxy resin, this epoxy resin component becomes a compatibilizer with the matrix resin and a curing agent. The present inventors have discovered that the silicone component is uniformly and differentially contacted with the matrix resin in the form of fine particles, and that this resin does not adversely affect moldability and productivity, and the above-mentioned problems can be solved at once, leading to the present invention.

That is, the object of the present invention is to provide a curable epoxy resin composition that does not have the above-mentioned problems, and in particular, a curable epoxy resin composition that has moldability equivalent to that of the epoxy resin itself and that does not generate cracks due to internal stress. An object of the present invention is to provide a composition.

[Means for solving the problems and their effects] The present invention consists of (a) 100 parts by weight of an epoxy resin, (b)
1 part of phenolic resin 0 to 100 Jiti, and (iii) a silicone-modified epoxy resin obtained by reacting an amino-modified silicone having an amino group only at one end of the polysiloxane chain with an epoxy resin.
Curable epoxy resin composition comprising 1 to 100 parts by weight The present invention will be described in detail below.

The epoxy resin used as the component (a) for Zero-Hatsu +11J may be any epoxy resin having at least two epoxy groups in one molecule, and all conventionally known epoxy resins can be used. Examples of such epoxy resins include diglycidyl ether to bisphenol, Ebibis type epoxy resin which is a polymer thereof, bisphenol F type epoxy resin, resorcin type epoxy resin, tetrahydroxyphenylethane type epoxy resin, and cresol novolak. Examples include type epoxy resins, polyolefin type epoxy resins, alicyclic type epoxy resins, and their halides. This component may be used alone or in combination of two or more.

Next, the phenol resin as the (oral) component used in the present invention acts as a curing agent, and phenol novolac resin, cresol novolac resin, bisphenol A, polyvarabinyl phenol resin, etc. are used.

The compounding date varies depending on the fjTt type of resin (a)
The amount is 1 to 100 parts by weight, preferably 1 to 80 parts by weight, based on 100 parts by weight of the component. In addition to this curing agent, imidazoles and phosphines such as triphenylphosphine can also be used as curing accelerators.

Next, the silicone-modified epoxy resin as component (c) of the present invention imparts stress relaxation effects to the composition of the present invention without reducing the moldability as a molding material, which is the greatest objective of the present invention. be. The amino-modified silicone having an amino functional group only at one end of the polysiloxane chain, which is a component of component (c), is represented by the following general formula.

RRR (In the formula, R is a monovalent hydrocarbon group, X is a monovalent a group having an amino group, and m is 2 to 1ooo.) Here, R is an intermediate or different monovalent hydrocarbon group. Examples of these include alkyl groups such as methyl, ethyl, propyl, and butyl, aryl groups such as phenyl and phenylethyl, aralkyl groups, and trimethoxysilylethyl groups.

X is a monovalent organic group having one amine 7 group, and is a primary amine such as an aminopropyl group, a secondary amine such as an N-normal butylaminopropyl group, an N-methylaminoisobutyl group, or a N-cyclohexyl group. An example is an aminoprobyl group.

The degree of polymerization of this polysiloxane chain is not particularly limited, but if it is too small, the stress relaxation effect will not be sufficient, and if it is too large, the reactivity with the epoxy resin will be poor.(a) Silicone-modified epoxy resin with good dispersibility with the component will not be obtained.

From this point of view, the degree of polymerization is 2 or more and 1000 or less, preferably 5 or more and 600 or less.

In the present invention, among such silicones modified with amino at one end, those having a secondary amino group at one end of the polysiloxane chain are preferred.

The epoxy resin, which is another component, is used to finely disperse the silicone modified with an amine at one end in the epoxy resin composition. The same components as (a) may be used, or other types of components may be used.

The reaction between the silicone modified with amino at one end and the epoxy resin as described above is carried out by heating and stirring in the presence of a catalyst such as imidazoles, tertiary amines or triphenylphosphine.

Further, it is usually desirable to use a solvent such as dimethylformamide or methyl ethyl ketone.

The blending amount of component (c) is 1 to 100 parts by weight, preferably 5 to 50 parts by weight, per 100 parts by weight of component (a). If it is too small, the effect of the addition of component (c) will not be achieved, and if it is too large, the balance of the epoxy resin will be lost and the original properties of the epoxy resin will be impaired.

Various additives can also be blended into the epoxy resin composition of the present invention. Examples of these additives include fumed silica and fused silica.

Inorganic fillers represented by crystalline silica, alumina, alumina hydrate, talc, diatomaceous earth, mica, asbestos, calcium carbonate, glass peas, glass minerals, antimony oxide, halogen compounds, phosphorus compounds, etc. Examples include flame retardants such as carnauba wax, higher fatty acid metal salts, internal mold release agents such as ester waxes, silane coupling agents, pigments, and dyes.

The epoxy resin composition of the present invention comprises the above component (a),
It is easily produced by uniformly kneading the components (b) and (c) using a mixing device such as a two-roller, an extruder, a kneader mixer, or a Henschel mixer.

[Example] The present invention will be specifically explained below using Examples. In the Examples, the curable epoxy resin compositions were evaluated according to the following method. The epoxy resin composition was kneaded for about 5 minutes using twin screw rolls heated to about 80°C. After cooling, it was crushed and made into tablets at 175℃, 74 kgf/cg.
+', transfer molding for 3 minutes, 180'C
/6 hours of after-curing was performed to obtain a cured molded product. Gold when molding! ! In addition to observing moldability such as mold releasability, mold warpage and release properties, the bending strength and flexural modulus of the cured molded product were measured. Spiral flow was also measured using another tablet.

In addition, in this measurement method, the measured values of mold stain, scratch strength, flexural modulus, and spiral flow were obtained by the following method.

O Mold stain: When molding was performed 20 times using the same mold, stains on the mold surface were observed with the naked eye, and the presence or absence thereof was reported.

O Bending strength and flexural modulus: A test bar conforming to ASTM D-790 was molded under the above conditions, and the flexural strength and flexural modulus of this test bar were measured using a Tensilon.

○Spiral flow: Measured under the conditions of 175°C and 74 kgf/cm' using a mold conforming to EMMI standards.

Reference Example 1 Synthesis of Silicone Modified P [Epoxy Resin (A) In a 300-meter 4-tube flask equipped with a thermometer, a cooling condenser, and a stirring bar, one terminal aminopropyl-modified polydimethylsiloxane (amino equivalent: 3900) shown by the following formula was prepared.
g.

(In the formula, n-Bu is n-butyl group) Epoxy cresol novolak resin (epoxy ffi 220)
20 g, triphenylphosphine as catalyst 0
．． 4g, and N,N'-dimethylformamide 5
0 g was charged and reacted at 130°C for 3 hours under a nitrogen gas atmosphere. The reaction solution became a homogeneous brown transparent solution. After the reaction was completed, the solvent was distilled off to obtain a brown solid. The melting point of this product was about 60°C.

Reference Example 2 Synthesis of silicone-modified epoxy resin (B) In Reference Example 1, one terminal secondary amino-modified polydimethylsiloxane (amino H13900) 20 gx epoxy cresol novolac resin (epoxy H122
0) The reaction was carried out under the same conditions as in Reference Example 1 except that 20 g was used. The reaction solution became a homogeneous brown transparent liquid. After the reaction was completed, the solvent was distilled off to obtain a brown solid.

The melting point of this product was about 65°C.

Reference Example 3 Synthesis of silicone-modified epoxy resin (C) In Reference Example 1, 45 g of one-end aminopropyl-modified polydimethylsiloxane (amino equivalent +700) shown in the following formula.

Bisphenol A type epoxy resin (epoxy FFt
190) The reaction was carried out under the same conditions as in Reference Example 1 except that 1 Og was used. The reaction solution turned into a homogeneous brown transparent liquid. After the reaction was completed, the solvent was distilled off to obtain a brownish paste.

Reference Example 4 Synthesis of silicone-modified epoxy resin (D) Using the same apparatus as in Reference Example 1, 45 g of one-end secondary amino-modified polydimethylsiloxane represented by the following formula was synthesized with bisphenol A-type epoxy resin (i122 per epoxy resin).
0) The reaction was carried out under the same conditions as in Reference Example 1 except that 10 g was used. After the reaction was completed, the solvent was distilled off to obtain a brownish paste.

Examples 1 to 4 Epoxy cresol novolak resin with an epoxy equivalent of 220 [manufactured by Nippon Kayaku Co., Ltd., trade name EOCN-1020]
Phenol novolak resin with phenol fil 00 [manufactured by Showa Kobunshi Co., Ltd., trade name BRG-5581, fused silica, 2-methyl-4-imidazole as a curing accelerator, carnauba wax as an internal mold release agent, and Reference Example 1
Silicone-modified epoxy resin (A) synthesized in ~4 ~(
D) in the number of parts shown in Table 1, and heated at 80 to 90°C for 2 hours.
The mixture was kneaded for 5 minutes using shaft rolls.

Thereafter, the resulting mixture was cooled and ground to obtain a curable epoxy resin composition for molding. Using this composition, the above-mentioned mold releasability, release property, rib strength, flexural modulus, and spiral flow were measured.

The results of these measurements are shown in Table 1.

Comparative Examples 1 to 3 Curable epoxy resin compositions for molding having the compositions shown in Table 1 were produced in the same manner as in Examples 1 to 4, and evaluated in the same manner. These evaluation results are also listed in Table 1. The amino-modified silicone oils E and F used in Comparative Examples 2 and 3 had the following chemical structures, and were added during twin-roll kneading.

(Oil E) (Oil F) Comparative Example 4 Synthesis of silicone-modified epoxy resin (G) Using the same equipment as in Reference Example 1, 20 g of both-end aminopropyl-modified polydimethylsiloxane (E) used in Comparative Example 2, Reference Reference example 1 except for 20g of epoxy resin used in example 1
The reaction was carried out under the same conditions. The reaction product became a homogeneous brown color and clear. After the reaction was completed, the solvent was distilled off to obtain a brown solid. This material had rubber elasticity and did not melt even when heated. Using this, evaluations similar to Examples 1 to 4 were performed. The results are also listed in Table 1.

Comparative Example 5 Synthesis of silicone-modified epoxy resin (H) Using the same apparatus as in Reference Example 1, the side chain aminoethyliminoprobil-modified polydimethylsiloxane (F) 20 used in Comparative Example 2 was synthesized.
g, The reaction was carried out under the same conditions as in Reference Example 1 except for 20 g of the epoxy resin used in Reference Example 1. The reaction product became a homogeneous brown clear liquid. After the reaction was completed, the solvent was evaporated to obtain a brown solid.

This material had rubber elasticity and did not melt even when heated. Using this, evaluations similar to Examples 1 to 4 were performed. The results are shown in Table 1. Table 1 [Effects of the Invention] The curable epoxy resin composition of the present invention has components (a) to (
It consists of component (c), and in particular contains component (c), a special silicone-modified epoxy resin, so it has moldability equivalent to that of the epoxy resin itself, and has the characteristics of not generating cracks due to internal stress. .

patent distributor Toshi Dow Corning Silicone Co., Ltd. Procedural Amendment

Claims (1)

[Scope of Claims] (a) 100 parts by weight of an epoxy resin, (b) 0 to 100 parts by weight of a phenolic resin, and (c) reaction of an amino-modified silicone having an amino group only at one end of the polysiloxane chain with an epoxy resin. A curable epoxy resin composition comprising 1 to 100 parts by weight of a silicone-modified epoxy resin.