Tatsuta Electric Wire & Cable Co., Ltd.

Nintendo Co., Ltd.

Hisatoshi Murakami

Tsunehiko Terada

Shinichi Wakita

Fumio Nakatani

Shohei Morimoto

Hiroaki Umeda

Kazumasa Eguchi

Katsuya Nakagawa

Kiyoshi Iwai

A conductive paste is provided, which has good conductivity and good adhesiveness to substrates and has good long-lasting stability of these properties, and which, when applied to a through-hole of a multi-layered substrate, ensures improved reliability of bonding to the end faces of conductive layers in the through-hole. Therefore, the paste does not require through-hole plating. The conductive paste comprises (A) 100 parts by weight of a resin component that contains an acrylate resin and an epoxy resin, (B) from 200 to 1800 parts by weight of a metal powder of at least two metals that contain at least one low-melting-point metal having a melting point of not higher than 180&#xb0; C. and at least one high-melting-point metal having a melting point of not lower than 800&#xb0; C., (C) from 0.5 to 40 parts by weight of a curing agent that contains from 0.3 to 35 parts by weight of a phenol-type curing agent, and (D) from 0.3 to 80 parts by weight of a flux.

Conductive paste multilayered board including the conductive paste and process for producing the same

The invention provides a conductive, flexure-resistant electromagnetic-shielded flexible printed circuit assembly obtainable by forming a copper foil circuit on a heat-resistant plastic film, disposing successively thereon an undercoat layer, a metal-powder-containing electromagnetic paste shield layer and an overcoat layer, with the ground pattern of the copper foil circuit being electrically connected to the above shield layer through the undercoat layer at appropriate intervals.

Electroconductive coating composition, a printed circuit board

Novel compounds, 1,2-N-acyl-N-methylene-ethylenediamines of formula (I) are useful as dispersants, rust inhibitors, curing promoters for epoxy resins, electroconductivity-imparting agents, mold lubricants, etc. ##STR1## where R is a hydrogen atom or a hydrocarbon group. An electroconductive paste with excellent electroconductivity and much improved long-term stability is obtained by mixing 100 parts by weight of a thermosetting resin with from 250 to 900 parts by weight of a metal filler and from 1 to 50 parts by weight of the 1,2-N-acyl-N-methylene-ethylenediamine; or by adding from 250 to 900 parts by weight of a metal filler coated with the 1,2-N-acyl-N-methylene-ethylenediamine to 100 parts by weight of a thermosetting resin.

1,2-N-acyl-N-methylene-ethylenediamine, and electroconductive paste

The invention relates to an electroconductive coating composition with excellent conductivity, adhesion to copper foil and solder dip resistance which is suitable for the formation of a jumper circuit and an electromagnetic shield layer, a printed circuit board fabricated with the above composition, and a durable electromagnetic-shielded flexible printed circuit assembly, wherein said coating composition comprises, by weight, 100 parts of copper metal powder coated with 0.05-0.2 parts of titanate or/and zirconate, 5-30 parts of resole phenolic resin, 0.5-4 parts of a chelating agent, 0.1-5 parts of an adhesion improving agent and 0.5-7 parts of a conductivity improving agent. This composition is less expensive than the silver paste, superior to the latter in the conductivity and adhesion to copper foil of the coating film and in solder dip resistance, thus being suited for the construction of a jumper circuit and an electromagnetic shield layer. It lends itself well to the mounting of IC, MSI, LSI, etc. by dipping in a molten solder bath.

The radiation noise suppression effect is enhanced by providing an insulation layer which is formed so that the circuit pattern is covered excepting at least a part of power source pattern or ground pattern on the substrate on which circuit pattern is formed, and a conductive layer which is formed so as to be connected to the uninsulated part of the power source pattern or the ground pattern on the insulation layer, by modifying pattern shape of the conductive layer and the insulation layer or by increasing or reducing the number of these layers.

Printed circuit board having enhanced EMI suppression

Printed circuit board

Printed circuit board with enhanced EMI suppression

A printed circuit board capable of preventing electromagnetic interference comprises a base plate composed of an insulating material. On the main surface of the base plate, a first electric conductive layer is formed by etching copper foil, which includes a signal electrode portion and a ground electrode portion. On the first electric conductive layer, an insulating layer such as a solder resist film is formed except for a part of the ground electrode portion, and on this layer, a second electric conductive layer is formed by screen-printing a copper ink so as to cover almost all of the first electric conductive layer. A part of the second electric conductive layer is connected to the ground electrode portion of the first electric conductive layer so that the second electric conductive layer acts as an electromagnetic shield. The copper ink is a mixture of copper powder, binder and other materials. A solder layer may be formed on the second electric conductive layer composed of the copper ink.

Printed circuit board capable of preventing electromagnetic interference

A conductive copper paste composition is adapted to yield a highly conductive film receptive to solders without pretreatment. This conductive paste comprises a copper metal powder, a resin component including a thermosetting resin, and an assortment of additives. In use, the paste is applied to an insulation substrate to a predetermined circuit pattern and cured in situ. Soldering can then be performed directly on the cured circuit. This contributes not only to the conductivity of the circuit but dispenses with the activation treatment and electroless plating or electroplating that have heretofore been essential prior to soldering. The invention, therefore, results in a substantial curtailment of production process and a proportional economic advantage. In addition, this conductive paste can be used in such applications as electrode and through-hole connections, formation of electromagnetic and electrostatic shield layers, and so on in the manufacture and assembly of electronic components and circuits.

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Higashiosaka, Japan

Hisatoshi Murakami