Sumitomo Bakelite Company Limited

Sigenori Yamaoka

Tsutomu Watanabe

Toshinaga Endo

Yukihiro Okabe

Akinobu Kusuhara

Masuo Mizuno

Takahiro Nakayama

Kochi Tanaka

Shoroku Kaneko

A crosslinked resin excellent in heat resistance, toughness, moisture resistance and adhesiveness can be obtained by the use of an epoxy compound having both alcoholic hydroxyl groups and epoxy groups in its molecule and an isocyanate compound having isocyanate groups in its molecule by first reacting the alcoholic hydroxyl groups of said epoxy compound and the isocyanate groups of said isocyanate compound to produce an epoxy prepolymer having urethane linkages stable at room temperature, followed by dissociating the urethane linkages of the prepolymer to regenerate the isocyanate groups and reacting said isocyanate groups with the epoxy groups of said epoxy compound. By carrying out the above-mentioned reaction between the isocyante groups and the epoxy groups in the presence of at least one member selected from the group consisting of amine compounds, carboxylic acid anhydrides, phenol novolac compounds and polyvinyl-phenol compounds and/or a bisimide compound, a crosslinked resin having higher heat resistance can be produced. Said prepolymer is excellent in storage stability and suitable for use in the production of laminates.

Crosslinked resin of epoxy compound and isocyanate and process for

Flexible printed circuit base board and method for producing the same

A heat-resistant resin composition suitable for use in multilayer super high density printed circuit boards, comprising a polyaminobismaleimide, a polyepoxy compound, and an aromatic vinyl copolymer containing as structural unit maleic anhydride and/or an alkyl maleate. This resin composition is excellent in thermal resistance and dimensional stability, which are important properties of a resin composition for practical use in lamination, and when used in lamination, exhibits favorable flow and curing properties so that it can be easily and economically processed under conventional laminating conditions. When used as a multilayer printed circuit board material, it is also characterized by excellent adhesion to a copper foil, particularly in bonding an inner circuit copper foil to the board. Although particularly suitable for use in multilayer printed circuit boards of numerous layers (eight or more layers) bearing highly packed circuits and as an interlayer adhesive sheet, the present resin composition can be used in general heat-resistant printed circuit boards and in general heat-resistant structural laminates.

Heat-resistant laminating resin composition and method for using same

A metal-clad laminate as a base board for a flexible printed circuit, consisting of a metal foil and a base sheet composed of a fibrous base material impregnated with a resin composition comprising a polyepoxy compound and a styrene copolymer containing structural units of maleic anhydride and/or a monoalkyl maleate. The said resin composition cures rapidly, so that the fibrous base material impregnated with said composition can be laminated in a continuous way with a metal foil and, moreover, the composition imparts to the resulting laminate flexibility and heat resistance suitable for flexible printed circuits. Said resin composition may comprise, in addition to the above-said components, a reactive epoxy diluent, an acrylonitrile-butadiene copolymer, and/or a mixture of a saturated polyester resin and a polyisocyanate compound, in order to improve the flexiblity and adhesion of the base sheet to metal foil. A prepreg obtained by impregnating the fibrous base material with the above-resin composition is not only suitable for manufacturing a flexible printed circuit base board excellent in soldering heat-resistance, bending resistance, and parts-loadability, but also usable as a heat-resistant cover-lay for flexible printed circuits or as an interlayer adhesive sheet.

Flexible metal-clad laminates and method for manufacturing the same

This invention provides an adhesive composition for use in flexible printed circuits, comprising a phenol-formaldehyde resin, a polyepoxy compound, an acrylonitrile-butadiene copolymer and/or a polyvinylacetal resin, and a styrenic copolymer containing as structural units maleic anhydride and/or an alkyl maleate. Being excellent in adhesive strength, flow property, rapid curability, and heat resistance after curing, the present composition is especially suitable for the continuous bonding of insulating plastic films, particularly a polyimide film, to conductor foils by use of a roll-laminator and gives heat-resistant metal-clad laminates excellent for flexible printed circuits which can be soldered at high temperatures. This invention further provides an adhesive composition having added thereto a compound consisting of an anhydride or a half-ester of cyclohexenepolycarboxylic acid in order to increase the flow property and adhesive strength of the adhesive composition at the time of bonding by means of a roll-laminator. All of the aforesaid adhesive composition not only permit the economical and technically advantageous production of laminates for heat resistant flexible printed circuits, but also can serve as an adhesive for either an overlay film for use in highly heat-resistant flexible printed circuits or an interlayer adhesive film.

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Yokohama, Japan

Sigenori Yamaoka