JPS61120822A - Epoxy resin - Google Patents

Abstract

PURPOSE:An epoxy resin of a low chlorine content and excellent heat resistance, obtained by reacting a specified hydroxyl group-containing polymer with epichlorohydrin. CONSTITUTION:An epoxy resin is obtained by reacting a hydroxyl group- containing polymer selected from among poly(p-hydroxystyrene) or its O- or m-isomer (A), poly(p-hydroxy-alpha-methylstyrene) or its O- or m-isomer (B), a copolymer of component A with component B (C), and a component A/methyl methacrylate copolymer in which the proportion of hydroxystyrene is 50-99% (D) with epichlorohydrin at 20-150 deg.C in a solvent such as tetrahydrofuran or 2-butanone. This resin is mixed with a curing agent, a cure accelerator, a modifier, etc., to obtain an epoxy resin composition for sealing semiconductor products.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to epoxy resins. More specifically, the present invention relates to an epoxy resin having low chlorine content and high heat resistance, a method for producing the same, and its use as a resin for encapsulating semiconductor products.

[Conventional technology]

It is well known that epoxy resins are widely used as sealing resins for semiconductor products, ie, semiconductor devices such as RC and LSI, and other electronic circuit components. This is because epoxy resins generally exhibit excellent electrical, mechanical, and thermal properties when cured using curing agents such as amines, acid anhydrides, and phenolic resins.

Conventional epoxy resins for encapsulating semiconductor products are synthesized by reacting 0-cresol novolak resin and epichlorohydrin. By the way, in order to react the 0-cresol novolac resin with epichlorohydrin to epoxidize the hydroxyl groups of the former, the 0-cresol novolak resin used as a starting material is used at the 0-position and the p-position of the cresol novolac. (due to the addition of formaldehyde and consisting of a mixture of condensed isomers) at 100-150°C under normal pressure, and
0~200岨H,! It was necessary to apply high temperatures of 70-100° C. under reduced pressure of i+. However, when the epoxidation reaction is carried out at such high temperatures, some of the epoxy rings of epichlorohydrin open and react with the cresol novolak, thus the chlorine atoms of epichlorohydrin are converted into the cresol novolak. There is a problem with being imported.

Epoxy resins with high chlorine contents obtained in this way may function satisfactorily as resins for encapsulating semiconductor products, but often cause circuit breakage. Moreover, such epoxy resins have insufficient heat resistance due to their irregular structure. actual,
The heat resistance of conventional epoxy resins produced as described above is limited to about 250°C.

[Problem that the invention seeks to solve]

As can be understood from the above description of the conventional technology, conventional epoxy resins are used for semiconductor products.

There are several drawbacks that hinder its use as a doyo. The present invention solves these drawbacks (problems) and can therefore be advantageously used for encapsulating semiconductor products.
The aim is to provide an epoxy resin with low chlorine content and high thermal properties.

[Failure to solve the problem]

As a result of research to solve the above-mentioned problems, the present inventors found that
Focusing on the fact that the hydroxystyrene-based polymer, which contains hydroxyl groups in its molecular structure and is specified below, has a linear regular structure and high heat resistance, it has been used as a starting material. - It has been found that the use of this polymer instead of cresol novolak resin and epoxidation with epichlorohydrin leads to a solution to the problem.

Hydroxyl group-containing polymers that can be used as starting materials in the practice of this invention are listed below: (i) poly p-hydroxystyrene or its 0- or m-isomer; (i1) poly p- Hydroxy α-methylstyrene or its 0- or m-isomer; (lit) a copolymer of the polymers (i) and (i1); or (iv) the proportion of hydroxystyrene moieties is 50 to 9
9, a copolymer of the polymer (i) and methyl methacrylate. Here, it is necessary that the proportion of the hydroxystyrene moiety be 50 to 99% in order to form an epoxy ring during epoxidation.

In the practice of the present invention, the epoxidation reaction is carried out between 20 and 15
It can advantageously be carried out at a temperature of 0°C, preferably from 30 to 80°C. This temperature range is effective in preventing excessive ring opening of the epoxy ring of epichlorohydrin.

Still, this epoxidation reaction can advantageously be carried out in the presence of a solvent such as, for example, tetrahydrofuran, 2-butanone, acetone, 1,4-dioxane, etc.

The epoxy resin of the present invention is treated with a curing agent and a curing agent according to a conventional method.
When mixed with a curing accelerator, a modifier, etc., it is possible to obtain an epoxy resin composition for encapsulating semiconductor products with far superior properties.

〔Example〕

Example 1: 120 g of poly p-hydroxystyrene (Mw=970
0 ) and 1009 epichlorohydrin to 1010
Dissolved in 0O tetrahydrofuran. While stirring the resulting solution at 60°C, 150 ml of 1
5% sodium bicarbonate was added dropwise over 30 minutes.

After continuing stirring for another 3 hours, 2000 m
When a mixture of equal volumes of isopropyl alcohol and deionized water in Step 1 was added, a resinous material was obtained. Next, the obtained resinous material was dissolved again in 500 ml of acetone, and then reprecipitated with 100 ml of deionized water. This reprecipitation was repeated two more times, and then
The obtained resinous material was heated at 80°C under a reduced pressure of 200allH&
It was dried. When the chlorine content of the epoxy resin thus obtained was measured using the flask combustion method, it was found to be 5 p.
It was pm. Furthermore, when the 4-thermal property of a resin obtained by mixing an equal weight of poly p-hydroxystyrene with this epoxy resin and thermosetting it was determined from HDT (heat distortion temperature), it was found that 3
The temperature was 20°C.

Example 2: Repeat the method described in Example 1 above. However, in the case of this example, epoxidation was carried out by dissolving 120.9 g of p-hydroxystyrene/methyl methacrylate (copolymerization ratio 1:1) and 60 g of epichlorohydrin in 1000 Inl of tetrahydrofuran.

The chlorine content of the epoxy resin obtained after washing and drying in the same manner as in Example 1 was measured and found to be 3pp.
It was m. However, the heat resistance (HDT) of the resin heat-cured with polyp-hydroxystyrene was 290°C.

〔Effect of the invention〕

According to the present invention, it is possible to obtain an epoxy resin that has a low chlorine content and high heat resistance, and therefore it is possible to achieve satisfactory encapsulation of semiconductor products.

Claims (1)

[Claims] 1. The following hydroxyl group-containing polymer: (i) Poly p^-hydroxystyrene or its o^- or m^-isomer; (ii) Poly p^-hydroxy α-methylstyrene or its o^- or m^-isomer; (iii) a copolymer of the polymers (i) and (ii); or (iv) the proportion of the hydroxystyrene moiety is 50 to 99%.
An epoxy resin produced by reacting a copolymer of the polymer (i) and methyl methacrylate with epichlorohydrin.