JPH0637545B2 - Epoxy resin composition with excellent transparency for transfer mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to an epoxy resin composition capable of obtaining a molded article having excellent transparency, for example, an epoxy resin composition for transfer molding, which is useful for sealing a light emitting element, a light receiving element and the like. It is a thing.

[Industrial application] Epoxy resins have been known to be excellent in electrical properties, moisture resistance, heat resistance, etc., and generally, amine-based curing agents and acid anhydride-based curing agents are widely used as curing agents. It's being used.

However, an epoxy resin composition using an amine-based curing agent undergoes significant discoloration during curing or during use after curing, especially when left at a high temperature, and has good light transmittance in addition to the above characteristics. However, it cannot be applied as a sealing material for a light emitting element or a light receiving element.

On the other hand, since the epoxy resin composition using an acid anhydride-based curing agent generally has a slow curing rate, it is common to further add a curing accelerator. No remarkable discoloration is observed. Therefore, unlike the amine-based curing agent, it can be sufficiently applied as a sealing material for a light emitting element, a light receiving element and the like.

[Conventional technology]

However, most of the conventional compositions of this type of acid anhydride type curing agent have been liquid compositions for casting. In recent years, the emergence of a solid composition capable of transfer molding excellent in workability and mass productivity has been desired.

[Problems to be solved by the invention]

Acid anhydride curing agents that are solid at room temperature include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic acid, maleic anhydride, tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, and methylcyclohexene. Examples include dicarboxylic acid anhydrides and polyazelaic acid anhydrides, but both have conjugated double bonds in the molecule, so transfer molding with a composition using these acid anhydrides resulted in molding. When the product is cured or used after curing, a slight discoloration occurs, especially when the product is left at a high temperature, and the light transmittance decreases.

As an acid anhydride having no conjugated double bond in the molecule,
Although cis-type hexahydrophthalic anhydride can be mentioned, there is a problem in that workability is poor because the melting point is 34 ° C. or lower.

[Means for solving problems]

The object of the present invention is a solid at room temperature, by using a trans-cyclohexane-1,2-dicarboxylic anhydride that does not contain a conjugated double bond in the molecule as a curing agent, epoxy resin for transfer mold excellent in transparency To provide a composition.

[Action]

The epoxy resin used in the present invention can be widely applied as long as it is solid at room temperature, and various types such as bisphenol A epoxy resin, novolac epoxy resin, and cycloaliphatic epoxy resin can be used. These epoxy resins may be used alone or in combination of two or more.

The curing agent used in the present invention is trans-cyclohexane-1,2-dicarboxylic acid.

The amount of the curing agent used is usually 0.6 to 1.5 equivalents, more preferably 0.8 to 1.2 equivalents, relative to the epoxy resin. The reason for this is that if it exceeds this range, the reaction does not proceed sufficiently and the physical properties of the cured product deteriorate.

The curing accelerator used in this invention is 2-ethyl-
4-methylimidazole, 2-methylimidazole, 1-
Imidazoles such as benzyl-2-methylimidazole, 1.8-diazabicyclo- (5,4,0) undecene-7 (D
BU), DBU / octylate, DBU / formate, mono DBU salt of orthophthalic acid, partial DBU salt of phenol novolac resin, and the like. The amount of these curing accelerators used is
It is usually 0.05 to 5 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight. If this amount is too small, the gelation time becomes long and the curing workability is deteriorated. On the other hand, if the amount is too large, curing rapidly progresses, resulting in a large amount of heat generated during curing, and storage stability deteriorates.

Examples of the internal release agent used in the present invention include long-chain fatty acids such as stearic acid, metal salts of long-chain fatty acids represented by zinc stearate and calcium stearate, carnauba wax, ester wax represented by montan wax, and the like. is there.

In addition to these, a colorant, a filler, a plasticizer, an antioxidant and the like may be added in a ratio that does not adversely affect the effect of the present invention.

〔Example〕

Example 1 100 parts by weight of bisphenol A type epoxy resin (mp 68 ° C., epoxy equivalent 473), trans-cyclohexane-1,2
35 parts by weight of dicarboxylic acid (mp 140 ° C., acid anhydride equivalent 154), 1 part by weight of orthophthalic acid mono DBU salt, and 1 part by weight of zinc stearate are kneaded by a hot roll at 90 to 100 ° C.,
It was cooled and pulverized to obtain the epoxy composition of the present invention. The composition obtained was transfer-molded at a molding temperature of 150 ° C. (molding time of 4 minutes) and after-cured at 150 ° C. for 2 hours to prepare a test piece of 25 × 30 × 5 mm. This test piece was produced. The light transmittance of this test piece was 92%, and it was
The light transmittance after 00 hours was 88%.

Example 2 Instead of the bisphenol A type epoxy resin, A test piece was prepared under the same composition and conditions as in Example 1 except that 40 parts by weight of the cycloaliphatic epoxy resin represented by (mp65 ° C., epoxy equivalent 174) was used. The light transmittance of this test piece is 95%, and the light transmittance after heating at 150 ° C for 500 hours is
It was 94%.

Comparative Example 1 A test piece was prepared under the same conditions as in Example 1 except that 32 parts by weight of tetrahydrophthalic anhydride (mp 100 ° C., acid anhydride equivalent 152) was used as a curing agent. The light transmittance of this test piece is 80.
%, And the light transmittance after heating at 150 ° C. for 500 hours was 58%.

[Comparative Example 2] Endmethylenetetrahydrophthalic anhydride (mp
A test piece was prepared under the same conditions as in Example 2 except that 40 parts by weight of 164 ° C. and an acid anhydride equivalent of 166) were used. The light transmittance of this test piece is 79%, and the light transmittance after heating at 150 ° C for 500 hours is 55%.
%Met.

[Effect of the Invention] According to the present invention, it is possible to obtain an epoxy resin composition for transfer molding which does not lose transparency even when heated at high temperature for a long time.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location H01L 31/02 33/00 N 7514-4M (72) Inventor Yoshihiro Nakata Kamihara, Kawasaki, Kanagawa 1015 Odanaka, Fujitsu Limited (56) Reference JP 59-19380 (JP, A) JP 59-113673 (JP, A) JP 60-140884 (JP, A) JP 61- 188414 (JP, A)

Claims (1)

[Claims] 1. An epoxy resin composition for transfer molding, comprising an epoxy resin which is solid at room temperature, an acid anhydride curing agent which is solid at room temperature, a curing catalyst, and a mold release agent. An epoxy resin composition for transfer molding having excellent transparency, which comprises using trans-cyclohexane-1,2-dicarboxylic anhydride as an agent.