Stock material or miscellaneous articles – Composite – Of epoxy ether
Reexamination Certificate
2000-06-26
2001-10-02
Moore, Margaret G. (Department: 1712)
Stock material or miscellaneous articles
Composite
Of epoxy ether
C428S415000
Reexamination Certificate
active
06296940
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flame-retardant resin composition showing excellent flame retardancy without using any halogen-based flame retardant, as well as to a sealant for semiconductor, using the composition.
2. Related Art Statement
Thermosetting resins typified by epoxy resins, etc. are in wide use in parts of electric or electronic appliances, etc. for their excellent properties. In many cases, flame retardancy is imparted to the thermosetting resins to allow them to have safety to fire. The flame retardancy of these resins has generally been achieved by using a halogen-containing compound such as brominated epoxy compound or the like. While halogen-containing compounds have high flame retardancy, aromatic bromine compounds liberate bromine or hydrogen bromide (these are corrosive) when thermally decomposed and, when decomposed in the presence of oxygen, may form a polybromodibenzofuran or a polydibromodibenzoxine (these are very toxic). Further, bromine-containing waste materials are very difficult to dispose.
It is well known that for the above reasons, extensive study is being made on phosphorus compounds as a flame retardant replacing the bromine-containing flame retardant. Addition of a phosphoric acid ester or the like to an epoxy resin, however, has limited applications because of problems of bleeding and hydrolysis. Further, ordinary phosphoric acid ester compounds having a functional group such as phenolic hydroxyl group or the like cause hydrolysis and liberate free phosphoric acid, which invites conspicuous impairment of electrical properties or reliability.
OBJECT OF THE INVENTION
An intensive study has been made to solve the above problems and, as a result, the present invention has been completed. The present invention provides a resin composition which has high flame retardancy without using any halogen compound and which does not impair the properties of an article to which the composition is applied.
SUMMARY OF THE INVENTION
The present invention resides in:
a flame-retardant resin composition comprising:
(A) an epoxy resin other than halogenated epoxy resins, having at least two epoxy groups in the molecule,
(B) a curing agent, and
(C) a product obtained by reacting (C1) a phosphorus compound having at least one P-H linkage in the molecule, with (C2) a compound having, in the molecule, at least one functional group selected from the group consisting of C—C double bond, epoxy group, alcoholic hydroxyl group and carbonyl group, and at least one functional group selected from the group consisting of epoxy group, phenolic hydroxyl group, amino group, cyanate ester group and isocyanate group,
and having a phosphorus content of 0.3% by weight to 8% by weight; and
a sealant for semiconductor, using the above composition.
DETAILED DESCRIPTION OF THE INVENTION
As mentioned above, addition of a phosphoric acid ester or the like to an epoxy resin has limited applications because of problems of bleeding and hydrolysis. Further, ordinary phosphoric acid ester compounds having a functional group such as phenolic hydroxyl group or the like cause hydrolysis and liberate free phosphoric acid, which invites conspicuous impairment of electrical properties or reliability. In order to solve these problems of the prior art, the present invention has achieved both flame retardancy and reliability by (1) reacting a compound having a P-H linkage, with a functional group capable of causing an addition reaction or a condensation reaction with said compound, to form a phosphorus compound having a P-C linkage stable to hydrolysis and (2) reacting a matrix resin (an epoxy resin and a curing agent having a phenolic hydroxyl group) with a functional group reactive with said epoxy resin or said curing agent, to form a strong bond.
In the present invention, the epoxy resin (A) other than halogenated epoxy resins, having at least two epoxy groups in the molecule can be exemplified by bisphenol A type epoxy resin; bisphenol F type epoxy resin; bisphenol S type epoxy resin; phenolic novolac type epoxy resin; cresol novolac type epoxy resin; naphthalene type epoxy resin; biphenyl type epoxy resin; and N-glycidyl compounds of aromatic amines or heterocyclic nitrogen bases, for example, N,N-diglycidylaniline, triglycidyl isocyanurate and N,N,N′,N′-tetraglycidyl-bis(p-amino-phenyl)-methane. The epoxy resin (A) is not restricted to these examples. These compounds may be used in admixture of two or more kinds. The epoxy resin (A) excludes halogen-containing epoxy resins such as brominated bisphenol A epoxy resin, brominated novolac epoxy resin and the like because the resin composition of the present invention uses no halogen-based flame retardant. However, when the epoxy resin used in the present resin composition is an ordinary epoxy resin produced from epichlorohydrin, the chlorine contained in the epoxy resin is inevitably contained in the present resin composition, but the amount thereof is a level known to those skilled in the art and is an order of several hundreds of ppm in terms of hydrolyzable chlorine.
In the present invention, as the curing agent (B), there can be used all curing agents known to those skilled in the art. Examples thereof are amines such as C
2-20
straight chain aliphatic diamines (e-g. ethylenediamine, trimethylenediamine, tetramethylenediamine and hexamethylenediamine), metaphenylenediamine, paraphenylenediamine, paraxylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodicyclohexane, bis(4-aminophenyl)phenylmethane, 1,5-diaminonaphthalene, metaxylylenediamine, paraxylylenediamine, 1,1-bis(4-aminophenyl)cyclohexane, dicyandiamide and the like; novolac type phenolic resins such as phenolic novolac resin, cresol novolac resin, tert-butylphenol novolac resin, nonylphenol novolac resin and the like; phenolic resins such as resole type phenolic resin, phenol aralkyl resin and the like; polyoxystyrenes such as polyparaoxystyrene and the like; and acid anhydrides. The curing agent (B) is not restricted to these examples. When the present resin composition is used as a semiconductor sealant, the curing agent (B) is preferably a novolac type phenolic resin (e-g. phenolic novolac resin, cresol novolac resin, tert-butylphenol novolac resin or nonylphenol novolac resin), a resole type phenolic resin, a polyoxystyrene (e.g. polyparaoxystyrene) or a phenol aralkyl resin, for their excellency in moisture resistance, reliability, etc.
In the present invention, the phosphorus compound (C1) having at least one P-H linkage in the molecule, used for synthesis of the component (C) is preferably at least one phosphorus compound selected from the group consisting of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphine oxide, diphenyl phosphite and phenylphosphinic acid.
In the compound (C2) used for synthesis of the component (C), it is preferable that the C—C double bond as the functional group is at least one group selected from the group consisting of allyl group, acrylic group, methacrylic group and maleimide group, or that the alcoholic hydroxyl group as the functional group is hydroxymethyl group, or that the carbonyl group as the functional group is at least one group selected from the group consisting of carboxyl group, formyl group and acetyl group.
The component (C), which is a product obtained by the reaction of the phosphorus compound (C1) with the compound (C2), can be used as a single compound or in admixture of two or more compounds.
In the present invention, the reaction for synthesis of the component (C) is conducted by melt-mixing the phosphorus compound (C1) having a P-H linkage and the compound (C2) at a temperature not lower than the melting point of the compound (C1). The condensation reaction between the P-H linkage of the compound (C1) and the functional group of the compound (C2) is preferably conducted while the condensation water generated is being removed
Ito Mikio
Miyake Sumiya
Aylward D.
Moore Margaret G.
Smith , Gambrell & Russell, LLP
Sumitomo Bakelite Company Limited
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