Abstract: A photocurable ink composition for forming patterns resistive to electroless plating is disclosed which includes (a) an epoxy resin, (b) an aliphatic polyol polyglycidyl ether as a reactive, viscosity controlling agent, (c) a photopolymerization catalyst, and (d) hydrophobic silica particles as a thixotropic agent.

Abstract: A thermosetting resin composition suitable for forming an insulating layer to be interposed between two adjacent wiring patterns of a multilayer printed wiring board is disclosed which includes a bisphenol AD epoxy resin, an aromatic polyamine, mica having an average particle size of 50 .mu.m or less, and silica having an average particle size of 20 .mu.m or less, the average particle size of the silica being smaller than that of the mica, and the amount of the silica being 20-80% based on the total weight of the silica and the mica.

Abstract: A resist ink composition suitable for forming a masking pattern resistive against chemical attack by a chemical plating liquor is disclosed which comprises:a phenol novolak epoxy resin having an epoxy equivalent of 170-250;a phenol novolak resin having a softening point of 60.degree.-130.degree. C.;a montmorillonite organic complex such as bentonite ion-exchanged with an organic cation;a curing-accelerating catalyst; andan organic solvent.

Abstract: A conducting layer such as an additional wiring pattern or an electromagnetic insulation layer is formed on a conducting surface such as of a printed circuit board with an insulating layer being interposed therebetween, by a method which includes the steps of:(a) providing a liquid thermosetting composition containing an epoxy resin, a curing agent, a polymerizable compound having at least two acrylate or methacrylate groups and a photopolymerization initiator;(b) applying the composition to the conducting surface to form a coated layer;(c) irradiating actinic light on the coated layer to polymerize the polymerizable compound and to obtain a solid, thermosetting layer,(d) heating the thermosetting layer to cure the epoxy resin and to form the insulating layer; and(e) forming an electrically conducting layer on the cured resin layer. Steps (b) and (c) are repeated until the solid thermosetting layer has a desired thickness. Step (d) may be performed before or after step (e).

Abstract: A thermosetting resin composition suitable for forming an insulating layer to be interposed between two adjacent wiring patterns of a multilayer printed circuit board is disclosed which includes an aromatic epoxy resin having at least two epoxy groups, an aromatic polyamine mica having an average particle size of 50 .mu.m or less, and silica having an average particle size of 20 .mu.m or less, the average particle size of the silica being smaller than that of the mica, and the amount of the silica being 20-80% based on the total weight of the silica and the mica.

Abstract: A method of treating a metal-plated board for the removal of a hardened, alkali-soluble resin layer therefrom, comprising the steps of:(a) contacting a surface of the resin layer with an aqueous alkaline liquid such as an aqueous sodium carbonate solution to swell the surface;(b) abrading the resin layer having the swollen surface, step (b) being preceded by or simultaneous with step (a); and(c) then washing the abraded surface with an aqueous neutral liquid such as water.

Abstract: A resin composition hardenable by irradiation of a high energy ray is disclosed, which includes:(a) a resin selected from the group consisting of rosins and modified rosins and having an acid value of at least 150 and a Gardner color scale of not greater than 15;(b) a compound of the general formula (I):Y--CO--O--A--O).sub. m CO--CR.dbd.CH.sub.2 (I)wherein Y represents ##STR1## A represents an alkylene having 1-4 carbon atoms, R represents hydrogen or methyl and m is an integer of 1-4;(c) a hydroxyl group-containing compound having only one acrylic or methacrylic group and at least one hydroxyl group; and(d) a polyol compound having at least two hydroxyl groups. The resin composition is useful for plugging through-holes of a metal plated board in manufacturing printed wiring boards.

Abstract: A resin composition is disclosed comprising, as essential ingredients, (I) a urethanized epoxy resin or a urethanized epoxy resin acrylate or methacrylate, (II) a ketone resin and (III) a cross-linkable or polymerizable compound containing at least two ethylenically unsaturated groups.