Mitsubishi Gas Chemical Company, Inc.

Takamasa Nakai

Kenji Ishii

Hiroyuki Matsumoto

Morio Gaku

Yoshinori Kondo

Kenzi Ishii

Kenichi Moriyama

A process for the production of a copper-clad laminate which is improved in dimensional accuracy and freedom from bow and twist and shows nearly the same values of dimensional accuracy, thermal expansion coefficient and elastic modulus in the length and width directions, the process using:

Process for the production of copper-clad laminate

A metal foil-clad laminate obtained by lamination molding a resin-impregnated substrate and a metal foil, wherein the resin-impregnated substrate contains from 5 to 30% by weight of at least one inorganic filler selected from the group consisting of calcined kaolin, spherical fused silica, non-swellable synthetic mica, and a glass fine powder, the filler having an average particle diameter of from 0.1 to 5 .mu.m and at least 90 wt % of the filler having a particle diameter of from 0.02 to 5 .mu.m, and the resin-impregnated substrate is used as at least a surface layer of the laminate or as a resin-impregnated substrate which adheres the metal foil, thereby providing a surface smooth metal foil-clad laminate having a diminished surface undulation attributable to the substrate.

Metal foil-clad laminate having surface smoothness

A process for producing a thin copper foil-clad circuit board substrate which comprises subjecting a copper foil-clad circuit board substrate (a) comprising an electrically insulating support overlaid on one or both sides with a copper foil having an average thickness of 12 .mu.m or more to etching with a copper-etching solution thereby to etch the whole surface of the copper foil at a predetermined etching rate selected from the range of from 0.01 to 0.4 .mu.m/sec, thereby to reduce the thickness of the copper foil on at least one side of the insulating support to 10 to 80% of its original thickness with the thickness variation of the remaining etched copper foil being within .+-.1.0 .mu.m on the basis of a desired thickness, wherein said copper foil-clad circuit board substrate (a) is one in which the surface of the copper foil is substantially free of adherent dust particles having an average particle diameter of 3 .mu.m or more.

Process for producing thin copper foil-clad circuit board substrate

An electrical laminate having an ability to absorb or shield ultraviolet rays having wavelength of 300-420 nm which comprises (i) at least one thermosetting resin-impregnated substrate, (ii) said substrate and a metal foil or (iii) said substrate, a metal foil and an adhesive layer for the metal foil comprising a thermosetting resin, characterized in that the thermosetting resin constituting part or all of said substrates or constituting said adhesive layer contains 0.2-6.0% by weight of a light absorber (A) on the basis of weight of the thermosetting resin, said light absorber is (a) an alkylthioxantone or a mixture of (a) said alkylthioxantone and (b) an ultraviolet rays-absorber.

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Tokyo, Japan

Takamasa Nakai