Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
1999-12-21
2001-11-06
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C257S793000, C523S466000
Reexamination Certificate
active
06312829
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to novolak epoxy resins having low viscosity which are useful as electric and electronic materials such as adhesives, paints, insulating materials, laminates and the like, epoxy resin compositions using such resins, and resin-sealed type semiconductor apparatuses.
2. Description of the Related Art
As an epoxy resin used as an electric and electronic material, particularly as an epoxy resin used for insulating a semiconductor element, there are known phenols novolak epoxy resins such as ortho cresol novolak resins and the like. On the other hand, recently, there is conducted a method in which an epoxy resin having low viscosity is used in an epoxy resin composition having high filler content, along with change in form of a semiconductor package such as reduction in thickness thereof and the like. For example, epoxy resins having low viscosity such as di-functional biphenyl epoxy resins and the like are used recently. Also, regarding phenols novolak epoxy resins typically including an ortho cresol novolak resin, a technology has been developed for obtaining an epoxy resin having sharp molecular distribution in which the binuclear compound content is low and the tri- to hexa-nuclear compound content is high, and epoxy resins have been obtained having low viscosity and high heat-resistance simultaneously. Technologies for obtaining such an epoxy resin having sharp molecular distribution in which the tri- to hexa-nuclear compound content is high are described in Japanese Patent Application Laid-Open (JP-A) Nos. 1-190722, 2-88628, 4-220422, 9-216932 and the like.
Conversely, as the novolak epoxy resin having high binuclear compound content, epoxy resins having low softening temperature are commercially available. For example, as such an ortho cresol novolak epoxy resin, “SUMIEPOXY ESCN-195LL” (trade name: manufactured by Sumitomo Chemical Co., Ltd.) and the like are known. In actuality, when this ortho cresol novolak epoxy resin is used for example in an epoxy resin composition for insulating a semiconductor wherein filler content is high in the composition, sufficiently low viscosity is not obtained.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a novolak epoxy resin having low viscosity which is useful as an electric and electronic material such as adhesives, paints, insulating materials, laminates and the like, an epoxy resin composition containing such a resin, and a resin-sealed type semiconductor apparatus.
According to the present invention, there is provided a novolak epoxy resin such as an ortho cresol novolak epoxy resin or the like having a GPC (gel permeation chromatography) area percentage of a binuclear compound of 15% or more, particularly 30% or more.
Also, there is provided, according to the present invention, an epoxy resin composition comprising as an essential component
(A) an epoxy resin containing the above-described epoxy resin having specific ratio of a binuclear compound, and
(B) an epoxy curing agent, and further, if necessary,
(C) an inorganic filler.
Further, there is provided, according to the present invention, a resin-sealed type semiconductor apparatus which is produced by sealing a semiconductor element by curing the above-described epoxy resin composition containing the components (A) to (C).
DETAILED DESCRIPTION OF THE INVENTION
The epoxy resin of the present invention is a novel novolak type epoxy resin of low viscosity, which has a GPC area percentage of a binuclear compound of 15% or more, particularly 30% or more, and preferably, is an ortho cresol novolak epoxy resin. The viscosity of the epoxy resin of the present invention is usually 1 poise or less, preferably 0. 5 poise or less at 150° C.
Herein, the binuclear compound means a unit wherein a unit obtained by reacting two molecules of phenols with one molecule of aldehydes or ketones has been epoxidized, among novolaks obtained by reacting phenols with aldehydes or ketones. For example, in the case of an ortho cresol novolak epoxy resin, the following structural unit is basically a binuclear compound.
Alternatively, when phenols are represented by
and aldehydes or ketones are represented by
a binuclear compound of an epoxy resin obtained by reacting them can be represented by the following structural formula,
In the above formulas, Examples of R, R
1
and R
2
are exemplified as follows.
Examples of R include, without being limited thereto, an alkyl group having 1-20 carbon atoms, an aryl group having 6-20 carbon atoms and a halogen atom. The symbol of n represents an integer from 0 to 4.
Examples of R
1
and R
2
include, without being limited thereto, hydrogen atom, an alkyl group having 1-20 carbon atoms, an aryl group having 6-20 carbon atoms and a halogen atom.
In the epoxy resin of the present invention, measurement of the GPC area percentage of a binuclear compound can be conduced for example by the following method.
First, conditions for measuring GPC of an epoxy resin are as follows.
Apparatus: GPC (LC-10A) manufactured by Shimadzu Corp.
Guard Column: TSK guard column H
XL
-L (6.0 mm &phgr;×4.0cm)
Column: TSK gel
G3000H
XL
(7.8 mm &phgr; × 30 cm)
G2000H
XL
(7.8 mm &phgr; × 30 cm)
G1000H
XL
(7.8 mm &phgr; × 30 cm)
three coloumns are connected in total
Moving Phase: tetrahydrofuran (guaranteed reagent, containing an additive)
Flow Rate: 1 ml/min, Detection: RI detector, Injection
Amount: 30 &mgr;l, Column Temperature: 40° C.
Sample Concentration: 0.15 g/10 ml (tetrahydrofuran solution)
The GPC area percentage of a binuclear compound can be obtained by measuring the area percentage of a peak of the binuclear compound emerging around 25 to 26 minutes on GPC measured under the measuring conditions described above.
The viscosity of the epoxy resin of the present invention is a value measured at 150° C. using a commercially available parallel plate type viscometer (trade name “CVO rheometer”, manufactured by Bohlin Instruments).
A method for preparing the epoxy resin of the present invention is not particularly restricted, and it can be obtained, for example, by a method in which phenols and aldehydes or ketones are subjected to a condensation reaction in the presence of an acid catalyst while controlling charging ratio of those raw materials to obtain novolaks, then, the novolaks are epoxidized, as well as other methods. The epoxy resin can also be obtained by a method in which the amount of compounds other than a binuclear compound of novolaks obtained by known methods is reduced by column treatment, heating and distillation in vacuo, and the like, then, the novolaks are epoxidized, as well as other methods.
Examples of the above-describedphenols include, but are not limited to, phenol, cresol, xylenol, trimethylphenol, methylethylphenol, methylpropylphenol, methylisobutylphenol, methylhexylphenol, methylcyclohexylphenol (including isomers, respectively), 3-methyl-6-t-butylphenol and the like. From the standpoints of easy availability and cost, phenol, cresol, xylenol and 3-methyl-6-t-butylphenol are preferable. These phenols may be used alone or in combination of two or more.
Examples of the above-described aldehydes or ketones include, but are not limited to, formaldehyde, acetaldehyde, acetone, cyclohexanone and the like. Any of them may also be provided in the form of an aqueous solution and the like.
As the above-described acid catalyst, there are exemplified inorganic acids such as fuming sulfuric acid, conc. sulfuric acid, aqueous sulfuric acid solution, conc. hydrochloric acid, hydrogen chloride gas, trifluorosulfonic acid and the like; organic acids such as p-toluenesulfonic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid and the like; heteropolyacid, acidic ion exchange resin and the like, and p-toluenesulfonic acid is suitably used.
Novolak formation by a condensation reaction can be conducted, for example, by adding dropwise aldehydes or ketones into a mixture of phenols and an acid catalyst, stirring t
Nakajima Nobuyuki
Yokota Akira
Aylward D.
Dawson Robert
Fitch Even Tabin & Flannery
Sumitomo Chemical Company Limited
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