Hitachi Chemical Company, Ltd.

Koichi Tsuyama

Atsushi Takahashi

Akishi Nakaso

Teiichi Inada

Kazunori Yamamoto

Yoshiyuki Tsuru

Shigeharu Arike

Akinari Kida

Hiroshi Takahashi

Kazuhisa Otsuka

Haruo Ogino

Makoto Fujikura

Nobuo Uozu

Yoshihiro Tamura

In a process for producing a multilayer printed circuit board comprising drilling holes for via holes in a composite film material containing at least a copper foil and an insulating half-cured adhesive layer, laminating the resulting film material on an innerlayer circuit substrate, ad electrically connecting an innerlayer circuit with an outer layer copper foil, when an adhesive resin flowed into the holes is roughened, or when a composite film material having a copper foil of less than 12 .mu.m thick formed on a carrier is used, or a special cushion material is further laminated on the laminate of the innerlayer circuit substrate and the film material, electrical connection reliability is enhanced and circuit density can be increased with easy steps.

Process for producing multilayer printed circuit board

A process for preparing a chemically platable thermosetting powder coating characterized by preliminarily kneading a composition comprising 3 to 50% by weight of a thermosetting resin, 5 to 60% by weight of an inorganic filler and up to 80% by weight of a rubber component comprising at least 10% by weight of a rubber having ethylenic double bonds and polar groups in the molecule, the amount of which rubber component constitutes the total amount of rubber component in the final powder coating, the rubber component content of the composition to be subjected to the preliminary kneading being at least twice the rubber component content of the final powder coating, said composition being heated at a temperature of at least the melting point of the thermosetting resin at least once during the course of the preliminary kneading, thereby to effect efficient dispersion of the components. The powder coating prepared according to the process of the present invention is substantially homogeneous due to the uniform dispersion of its components, thus providing good applicability thereof on an article, excellent levelling of a coated film of the powder coating when molten in the step of heat hardening and an improved peeling strength between the coated and heat-hardened film of the powder coating and a metal deposited thereon by chemical plating. The chemically platable thermosetting powder coating prepared according to the process of the present invention may further comprise a catalyst for chemical plating, at least 50% by weight of catalyst in the final powder coating being kneaded together with the above-mentioned composition in the step of preliminary kneading.

Process for preparing chemically platable thermosetting powder coating

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Shimodate, Japan

Koichi Tsuyama