Sumitomo Bakelite Company Limited

Yukihiro Okabe

Masuo Mizuno

Shigenori Yamaoka

Sigenori Yamaoka

Mitsutaka Waki

Kenmatsu Isozaki

Shoroku Kaneko

Kyotaro Nishi

Polyimide-type-resin-etching rate can remarkably be enhanced by combining tetramethylammonium hydroxide or an aqueous solution of tetramethylammonium hydroxide with at least one member selected from the group consisting of amide compounds represented by the following formula: ##STR1## and amide compounds represented by the following formula: ##STR2## and amine compounds represented by the following formula:

Etching agent for polyimide type resins and process for etching

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

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Yokohama, Japan

Yukihiro Okabe