Claims
- 1. A modified, substituted or unsubstituted, novolac epoxy resin represented by the formula (A), having improved characteristics of the cured resin for use in an electronic parts encapsulating composition: ##STR3## wherein m and n are selected such that, on the average, (i) the the sum of the epoxy groups ##STR4## and the modified epoxy groups (--CHOH--CH.sub.2 --O--R.sub.3) in the molecule is a number of 7 to 11, and (ii) the ratio of modified epoxy groups (--CHOH--CH.sub.2 --O--R.sub.3) to the sum of the epoxy groups ##STR5## and the modified epoxy groups (--CHOH--CH.sub.2 --O--R.sub.3) in the molecule is 0.01 to 0.15,
- R.sub.1 is a hydrogen atom, a halogen atom, an alkyl group or an aryl group,
- R.sub.2 is a hydrogen atom, an alkyl group, an aryl group or an aryl group substituted by glycidyl ether, and
- R.sub.3 denotes a dihydric aliphatic alcohol residue.
- 2. A method for the production of a modified, substituted or unsubstituted, novolac epoxy resin as claimed in claim 1, said method comprising:
- reacting a substituted or unsubstituted novolac epoxy resin of the following formula ##STR6## wherein p is selected such that, on the average, the novolac epoxy resin has 7 to 11 epoxy groups in the molecule
- R.sub.1 is a hydrogen atom, a halogen atom, an alkyl group or an aryl group, and
- R.sub.2 is a hydrogen atom, an alkyl group, an aryl group or an aryl group substituted by glycidyl ether
- with a dihydric aliphatic alcohol
- in the presence of caustic soda as a reaction catalyst.
- 3. The modified novolac epoxy resin of claim 1, wherein said dihydric alcohol is an aliphatic alcohol having at least one primary hydroxyl group.
- 4. The modified novolac epoxy resin of claim 3, wherein said dihydric alcohol is an aliphatic alcohol having 12 or less carbon atoms.
- 5. The modified novolac epoxy resin of claim 1, wherein said aliphatic alcohol is ethyleneglycol or propyleneglycol.
- 6. The modified novolac epoxy resin of claim 1, wherein said novolac epoxy resin is an .sigma.-cresol novolac epoxy resin.
- 7. An electronic parts encapsulating resin composition comprising the modified novolac epoxy resin of claim 1 and a hardener.
- 8. Electronic parts encapsulated in the encapsulating resin composition of claim 7.
Parent Case Info
This application is a continuation of application Ser. No. 08/234,946, filed Apr. 28, 1994 now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (4)
Number |
Date |
Country |
0281213 |
Sep 1988 |
EPX |
55-112231 |
Aug 1980 |
JPX |
0112231 |
Aug 1980 |
JPX |
58-74714 |
May 1983 |
JPX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
234946 |
Apr 1994 |
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