JPS6280601A - Epoxy resin composition for photocoupler - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin compsn. for photocoupler having high reliability and light transmissivity by specifying a content of metal in the resin compsn. comprising epoxy resin and a curing agent basing on the content of molten silica powder. CONSTITUTION:The content of metal in a resin compsn. contg. 30-70pts.wt. epoxy resin and a curing agent basing on 100pts.wt. molten silica powder is characterised to be <=50ppm. The reason why the content of epoxy resin and the curing agent is regulated to 30-70pts.wt. per 100pts.wt. molten silica is that the light transmissivity is deteriorated due to increase of scattering of light by the molten silica powder if the content is <=30pts.wt.; and that delamination would be caused at the interface of the molten silica powder and the external resin resulting inferiority in reliability if the content is >=70pts.wt. Further, the reason why the content of metal is regulated to <=50ppm is that the light transmissivity would be deteriorated due to increase of light absorption by the metal if the content of metal is >=50ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a NIX resin composition for photocouplers that has excellent reliability and light transmittance.

[Prior art]

A photocoupler is composed of an inner resin that seals a light emitting element and a light receiving element, and an outer resin that covers it. Conventionally, silicone resin has been used as the inner resin and epoxy resin has been used as the outer resin, but recently, research has begun to be conducted into applying epoxy resin as the inner resin for the purpose of cost reduction.

Epoxy resins have a higher elastic modulus than silicone resins and have greater thermal stress, so they contain a large amount of filler.
Rather than lowering the coefficient of thermal expansion, it is necessary to lower the thermal stress. However, on the other hand, the amount of light transmitted through the resin composition is largely lost due to the filler, and the prior art cannot obtain the light transmittance necessary to satisfy the function of the photocoupler.

[Purpose of the invention]

The present invention was developed as a result of research aimed at achieving high reliability and light transparency that could not be achieved with conventional Eixy resin compositions.
We obtained the knowledge that what inhibits the transmission of light is the metal substance in the resin composition, and based on this knowledge, we conducted various studies and completed this research.

[Structure of the invention]

The present invention provides a photocoupler for use in a resin composition containing 30 to 70 parts by weight of Eixy resin and a curing agent based on 100 parts by weight of fused silica powder, wherein the metal content is 50 ppm or less. The present invention relates to an epoxy resin composition.

In the present invention, based on 100 parts by weight of fused silica powder,
The reason for limiting the amount of epixy resin and curing agent to 30 to 70 parts by weight is that if it is less than 30 parts by weight, the amount of light scattered by the fused silica powder will increase, resulting in a decrease in light transmittance, and if it is more than 70 parts by weight, This is because peeling occurs at the interface with the outer resin, reducing reliability. Furthermore, the reason why the metal content i of the resin composition is limited to 50 ppm or less is that if it is more than so ppm, the amount of light absorbed by the metal increases, resulting in a decrease in light transmittance.

The epoxy resin composition according to the present invention is composed essentially of a synthetic resin, a curing agent, and a curing accelerator, and a mold release agent and a surface treatment agent may be added as necessary.

The epoxy resins used in the present invention include bisphenol A epoxy resins, novolak epoxy resins, alicyclic epoxy resins, etc. These epoxy resins can be used alone or in combination of two or more. May be used.

As the curing agent, polybasic carboxylic acid anhydrides may be used alone or in combination of two or more. Examples of these include phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, and the like. Alternatively, a phenol novolac resin may be used as a curing agent. The amount of curing agent to be added to the epixy resin is desirably 0.5 to 1.2 equivalents per 1 nexy equivalent; otherwise, serious defects may occur in moldability.

As a curing accelerator, ■ tertiary amine or its derivative trimethylamine, triethylamine, 2.3.4.6
．． 7.8.9.10-octahydro-pyramide (1=
2-a) Azepine, etc. or quaternary ammonium salts thereof ■Organophosphine compounds (a) Primary, secondary, M3 phosphine: octylphosphine, diphenylphosphine, butylphenylphosphine, tricyclohexylphosphine, triphenylphosphine, etc. (b) Novetaine-type adducts of organic tertiary phosphine and compounds having a π bond: maleic anhydride-triphenylphosphine adducts, thioincyanate-triphenylphosphine adducts, diazodiphenylmethane-triphenylphosphine adducts, etc. (c> Organic nitrile salt: (g3 PCH2121) Φcte.

(a,, PEt)e I e, (y33PEt)
eBree tc■ Organoaluminum compound (a) At (0R)3 (R: H, alkyl group, aryl group, aryl group-containing hydrocarbon group) Nialium isopropoxide, aluminum n-butoxide,
aluminum tert-butoxide, aluminum 5c
c-butyrate, aluminum benzoate, etc. (b) β-diketone complex of aluminum (aluminum chelate) Nialuminum acetylacetonato, aluminum triple oacetylacetonato, aluminum pentafluoroacetylacetonato, etc. ■Titanium compounds butyl titanate, titanium white, etc. , ■Acids Examples include para-toluenesulfonic acid.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an epoxy resin composition for photocouplers with excellent reliability and light transmittance, so that a light propagation system can be applied to products requiring high reliability at a low cost. It becomes possible.

〔Example〕

This will be explained below using Examples and Comparative Examples.

Examples 1 to 3 and Comparative Examples 1 to 3 100 parts by weight of fused silica powder, engineered mexi resin and X parts by weight of curing agent were mixed for a predetermined time, kneaded using a mixing roll, cooled to solidify, and pulverized to obtain a resin composition. A powder was obtained. The characteristics of a photocoupler assembled using the resin composition thus obtained were investigated.

In addition, the outer resin is EME-
5000 was used.

From Table 1, it can be seen that the examples are superior to the comparative examples.

Claims (1)

[Claims] An epoxy resin composition for a photocoupler, characterized in that the resin composition contains 30 to 70 parts by weight of an epoxy resin and a curing agent based on 100 parts by weight of fused silica powder, and has a metal content of 50 ppm or less.