Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
2001-07-25
2003-07-08
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C523S466000, C525S391000, C525S396000, C525S523000
Reexamination Certificate
active
06589656
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an epoxy resin composition comprising an epoxy resin, phenol-modified polyphenylene oxide obtained by redistribution reaction between a polyphenylene oxide and a phenol compound in the presence of a reaction initiator, and a hardening agent and, more specifically, an epoxy resin composition to be used as a material for preparing metal-clad laminates such as printed wiring boards, prepreg and metal-clad laminate using the composition
2. Description of Background Information.
As materials for preparing insulating boards such as printed wiring boards, epoxy resin compositions have popularly been used. With the increase in integration degree of electronic parts such as semi-conductors, there have been known, as materials for insulating boards having excellent high frequency properties such as excellent dielectric constant and a high glass transition temperature, epoxy resin compositions containing an epoxy resin, phenol-modified polyphenylene oxide having a number average molecular weight of 1000 to 3000 prepared by redistribution reaction between polyphenylene oxide and a phenol compound in the presence of a reaction initiator, and a hardening agent by, for example, Japanese Patent Laid-Open No. 291148/1997. The phenol-modified polyphenylene oxide is obtained by subjecting a high molecular polyphenylene oxide having a number average molecular weight of 10000 to 30000 to redistribution reaction to reduce the number average molecular weight to 1000 to 3000.
Such redistribution reaction sometimes generates a less reactive modified polyphenylene oxide by the reaction with a reaction initiator. Presence of such less reactive modified polyphenylene oxide may cause fluctuation in quality of products manufactured therefrom. Thus, it has been desired to improve a reactivity of the epoxy resin composition.
In addition, with a recent increasing demand for miniaturization, printed wiring boards in which the above-described epoxy resin composition is used have increasingly been made multi-layer. In manufacturing multi-layer printed wiring boards, there have been required materials having a better glass transition temperature or materials having a lower expansion coefficient since they are to be heat-treated.
This application is based on a Japanese Patent Applications 2000-224994 filed on Jul. 26, 2000, herein cooperated by reference.
SUMMARY OF THE INVENTION
This invention is made with the above-described circumstances in mind, and provides an epoxy resin composition comprising an epoxy resin, phenol-modified polyphenylene oxide, and a hardening agent, which shows a higher reactivity at a hardening reaction, a prepreg and metal-clad laminate using this epoxy resin composition.
Furthermore, the invention provides an epoxy resin composition capable of providing a metal-clad laminate having an excellent glass transition temperature.
Still further, the invention provides an epoxy resin composition capable of providing a metal-clad laminate having a lower expansion coefficient.
Yet further, the invention provides an epoxy resin composition capable of providing a metal-clad laminate which can attain a lower dielectric constant and a lower dielectric loss tangent.
As a result of intensive investigations to attain the objects of the invention, the inventors have found that the reactivity of an epoxy resin composition can be improved by using specific reaction initiators such as compounds represented by the formula (1), (2) or (3) and that an metal-clad laminate prepared from the epoxy resin composition containing as a constituent a phenol-modified polyphenylene oxide obtained by using the reaction initiator, has an excellent glass transition temperature and shows a lower expansion coefficient and lower dielectric properties, thus having completed the invention based on the findings. Also, as a result of further investigations, the inventors have found that phenol-modified polyphenylene oxides obtained by redistribution reaction in the presence of a particular reaction initiator such as compounds represented by the formula of (1), (2) or (3) and having a number average molecular weight of 4000 or less, do not cause deterioration of performance of printed wiring boards prepared from them, thus having completed the invention based on the finding.
Additionally, a number average molecular weight of the phenol-modified polyphenylene oxide as used herein means a molecular weight determined by measuring molecular weight distribution using gel permeation chromatography.
The present invention includes the following.
(1) An epoxy resin composition comprising:
an epoxy resin;
a hardening agent; and,
a phenol-modified polyphenylene oxide having a number average molecular weight of 1000 to 4000, which is prepared by carrying out a redistribution reaction between a polyphenylene oxide and a phenol compound in the presence of a reaction initiator which can be decomposed to generate an alcohol.
(2) The epoxy resin composition as described in the item (1), wherein the alcohol is an aliphatic alcohol.
(3) The epoxy resin composition as described in the item (1) or (2), wherein the alcohol has a boiling point of 150° C. or less.
(4) The epoxy resin composition as described in any one of the item (1) to (3), wherein the reaction initiator is a compound represented by formula (1):
wherein R and R′, which are the same or different, each represents an alkyl group.
(5) The epoxy resin composition as described in any one of the item (1) to (3), wherein the reaction initiator is a compound represented by formula (2):
wherein R
3
and R
4
, which are the same or different, each represents an alkyl group.
(6) The epoxy resin composition as described in the item (5), wherein the reaction initiator represented by the formula (2) is t-butyl peroxy isopropyl monocarbonate.
(7) The epoxy resin composition as described in any one of the item (1) to (3), wherein the reaction initiator is a compound represented by formula (3):
wherein R
1
represents an alkyl group, R
2
represents CH
3
or H.
(8) The epoxy resin composition as described in any one of the item (1) to (7), wherein the redistribution reaction is carried out in the presence of a catalyst together with the reaction initiator.
(9) The epoxy resin composition as described in the item (8), wherein the catalyst is cobalt naphthenate.
(10) The epoxy resin composition as described in claim (8), wherein the catalyst is compounded in an amount of 0.001 to 0.01. part by weight per 100 parts by weight of the polyphenylene oxide.
(11) A prepreg prepared by: impregnating a substrate with an epoxy resin composition described in any one of the item (1) to (10); and semi-hardening the epoxy resin composition.
(12) A metal-clad laminate comprising a metal foil and a prepreg described in the item (11), in which the epoxy resin composition is hardened.
(13) The metal-clad laminate described in item (12), wherein the epoxy resin composition in the prepreg is hardened by heat-pressing after the prepreg and the metal foil are superposed.
Since the phenol-modified polyphenylene oxide is prepared by using the above-described reaction initiator, there remain less unreacted materials. Hence, the metal-clad laminate has an excellent glass transition temperature and shows a lower expansion coefficient, a lower dielectric constant and a lower dielectric loss tangent.
DETAILED DESCRIPTION OF THE INVENTION
The first embodiment of the epoxy resin composition of the invention is described below.
The epoxy resin composition comprises an epoxy resin, a phenol-modified polyphenylene oxide (a polyphenylene oxide that have been modified with a phenol compound) having a number average molecular weight of 1000 to 4000, which is obtained by carrying out a redistribution reaction between a polyphenylene oxide and a phenol compound in the presence of a reaction initiator, and a hardening agent.
The phenol-modified polyphenylene oxide used in the epoxy resin composition can be obtained by subjecting a high molecular weight poly
Hayashi Takao
Komori Kiyotaka
Maekawa Tetsuya
Saito Eiichiro
Yoshimura Takeshi
Aylward D.
Dawson Robert
Greenblum & Bernstein P.L.C.
Matsushita Electric & Works Ltd.
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