Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Noninterengaged fiber-containing paper-free web or sheet...
Patent
1997-05-28
1999-09-21
Gulakowski, Randy
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Noninterengaged fiber-containing paper-free web or sheet...
428415, 428416, 428901, 428921, 4282974, 525500, 525504, 525524, 528 99, 528103, B32B 700
Patent
active
059551844
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an epoxy resin composition as well as a prepreg and a laminate containing the composition, and more particularly to a halogen-free flame-retardant epoxy resin composition, a prepreg impregnated with such composition, as well as to a laminate, copper-clad laminate and printed wiring board manufactured by using such prepreg.
BACKGROUND ART
In recent years, safety to humans including, for example, the air pollution problem attracts world-wide attentions. In this connection, electric and electronic appliances are required to be more harmless and more safe in addition to the requirement of a high flame retardancy. To be more specific, the electric and electronic appliances are required to be resistant to flame and, at the same time, not to generate noxious gases. It has been customary in the past to use a glass/epoxy as a substrate of a printed wiring board on which electric and electronic appliances are to be mounted. In general, a brominated epoxy resin containing bromine as a flame-retardant, particularly, tetrabromobisphenol-A type epoxy resin, is used for forming the substrate of the printed wiring board.
The brominated epoxy resin certainly exhibits a high flame retardancy, but generates a noxious hydrogen halide (hydrogen bromide) gas when burned. To overcome the difficulty, epoxy resin compositions containing non-halogen flame-retardants such as nitrogen compounds, phosphorus compounds, inorganic compounds, etc., have been developed, as reported in, for example, British Patent No. 1,112,139 and Japanese Patent Disclosure (Kokai) No. 2-269730. However, these flame-retardants give rise to a detrimental effect to the curing of the epoxy resin and impairs the humidity resistance of the cured composition. In addition, a glass cloth is less likely to be impregnated with the epoxy resin composition if the composition contains the non-halogen flame-retardants mentioned.
The present invention is intended to provide an epoxy resin composition which does not contain a halogen element but exhibits a good flame retardancy and which permits overcoming the above-noted problems inherent in the prior art.
The present invention is also intended to provide a prepreg impregnated with such an epoxy resin composition as well as a laminate, copper-clad laminate and printed wiring board using such a prepreg sheet.
DISCLOSURE OF INVENTION
According to a first embodiment of the present invention, there is provided a halogen-free flame-retardant epoxy resin composition, comprising (A) a bisphenol A type epoxy resin, (B) a novolak type epoxy resin, (C) a nitrogen-containing phenolic resin acting as a curing agent, (D) a curing accelerator, and (E) an inorganic filler, wherein the nitrogen-containing phenolic resin serves to impart a flame retardancy to the composition.
The nitrogen-containing phenolic resin may be an aminophenolic resin. However, it is preferable to use a co-condensation resin formed by the reaction among a phenolic compound, a guanamine compound and an aldehyde compound.
According to a second embodiment of the present invention, there is provided a halogen-free flame-retardant epoxy resin composition, comprising (A) a bisphenol A type epoxy resin, (B) a novolak type epoxy resin, (C) a phosphorus- and nitrogen-containing phenolic resin acting as a curing agent, (D) a curing accelerator, and (E) an inorganic filler, wherein the phosphorus- and nitrogen-containing phenolic resin serves to impart a flame retardancy to the composition.
The phenolic resin containing both phosphorus and nitrogen atoms should desirably be a reaction product among a phenolic compound, a guanamine compound, an aldehyde compound and a reactive phosphoric acid ester.
According to a third embodiment of the present invention, there is provided a halogen-free flame-retardant epoxy resin composition, comprising (A) a bisphenol A type epoxy resin, (B) a novolak type epoxy resin, (C-1) a reactive phosphoric acid ester, (C-2) a co-condensation resin of a phenolic compound, a guanamine compound
REFERENCES:
patent: 4501787 (1985-02-01), Marchetti et al.
Honda Nobuyuki
Sugiyama Tsuyoshi
Suzuki Tetsuaki
Gulakowski Randy
Toshiba Chemical Corporation
White John P.
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