Sumitomo Bakelite Company Limited

Masahiro Mitsui

Takeshi Hosomi

Tomoyoshi Honjoya

Toyoaki Kishi

Sei Nakamichi

There is disclosed a thermosetting resin injection molding machine comprising: a heating cylinder including a body having a device for introducing a resin material into said body, and a sleeve having an injection port for injecting the resin material; and a screw reciprocally movable in the heating cylinder, wherein the screw includes a body having a flight, and a piston portion provided at a front end of the screw body, and a diameter of the piston portion is smaller than a diameter of the flight; wherein an inner diameter of a working portion of the sleeve is smaller than an inner diameter of the heating cylinder body; wherein a length of the piston portion, a length of the working portion of the sleeve and an annular clearance between the working portion of the sleeve and the piston portion are so determined that a predetermined amount of the resin can remain for cushion molding at a front end of the piston portion during dwell after the injection of the resin material; and wherein a resin compressing portion is interposed between the piston portion and the screw body, and the resin compressing portion has a diameter which is larger than the diameter of the piston portion, and is smaller than the diameter of the flight.

Thermosetting resin injection molding machine

An insulating adhesive for a multilayer printed circuit board, which is to be laminated to an internal layer circuit board coated with an undercoating agent comprising an epoxy resin and a curing agent therefor, and which comprises as essential components:

Insulating adhesive for multilayer printed circuit board

A process for producing a multilayer printed circuit board which comprises coating a light and heat curable undercoating agent on an internal layer circuit board, irradiating the undercoating agent with active energy beams to make the same tack-free, then laminating thereto a metal foil having an insulating adhesive layer and subsequently heating the resulting assembly to integrally cure the same. When the undercoating agent is coated on an internal layer circuit board and irradiated with a light to be made tack-free, and thereto is laminated a copper foil having a thermosetting insulating adhesive by a rigid roll or the like, the undercoating agent is softened or fluidized and the surface is smoothened. When the resulting laminate is thereafter heated, the undercoating agent coated on the internal layer circuit board and the insulating adhesive coated on the copper foil are integrally cured. Since the insulating adhesive coated on the metal foil keeps the thickness, a multilayer printed circuit board having an excellent board thickness precision can be produced without depending on the percentage of the remaining copper foil in the internal layer.

Process for producing multilayer printed circuit board

An undercoating agent for a multilayer printed circuit board which comprises:

Growing community of inventors

Fujieda, Japan

Masahiro Mitsui