Abstract: A liquid thermosetting resin composition comprises (A) an epoxy resin, (B) a curing catalyst, and (C) a filler and is characterized by exhibiting a viscosity at 25° C. of not more than 1,500 dPa.s, a gel time of not less than 300 seconds at a temperature at which the composition exhibits a melt viscosity of not more than 10 dPa.s, and a gel time at 130° C. of not more than 600 seconds. In the production of a printed wiring board by superposing an interlaminar resin insulating layer and a conductive circuit on the surface of the wiring board having a conductive circuit pattern including hole parts, a hole filling process is performed by filling the hole parts mentioned above with the composition mentioned above, effecting precure of the composition by heating, then polishing and removing parts of the precured composition protruding from a surface defining the hole parts, and further heating the precured composition till final curing.

Abstract: A liquid thermosetting insulating resin composition and a method for permanently filling holes in a printed circuit board by the use of the composition are provided. The liquid thermosetting insulating resin composition comprises (A) an epoxy resin assuming a liquid state at room temperature, preferably in combination with (B) a phenolic resin assuming a liquid state at room temperature, (C) a curing catalyst, and (D) a filler, wherein the filler (D) contains a spherical filler and a ground filler. Preferably the spherical filler includes a spherical fine filler and a spherical coarse filler. In a method for permanently filling holes in the printed circuit board, the composition is applied to the board so as to fill the holes in the printed circuit board and precured by application of heat. Thereafter, the parts of the precured composition protruding from a surface defining the holes is removed by polishing and then the precured composition is further heated to cause final curing thereof.

Abstract: A liquid thermosetting resin composition comprises (A) an epoxy resin, (B) a curing catalyst, and (C) a filler and is characterized by exhibiting a viscosity at 25° C. of not more than 1,500 dPa.s, a gel time of not less than 300 seconds at a temperature at which the composition exhibits a melt viscosity of not more than 10 dPa.s, and a gel time at 130° C. of not more than 600 seconds. In the production of a printed wiring board by superposing an interlaminar resin insulating layer and a conductive circuit on the surface of the wiring board having a conductive circuit pattern including hole parts, a hole filling process is performed by filling the hole parts mentioned above with the composition mentioned above, effecting precure of the composition by heating, then polishing and removing parts of the precured composition protruding from a surface defining the hole parts, and further heating the precured composition till final curing.

Abstract: A liquid thermosetting insulating resin composition and a method for permanently filling holes in a printed circuit board by the use of the composition are provided. The liquid thermosetting insulating resin composition comprises (A) an epoxy resin assuming a liquid state at room temperature, preferably in combination with (B) a phenolic resin assuming a liquid state at room temperature, (C) a curing catalyst, and (D) a filler, wherein the filler (D) contains a spherical filler and a ground filler. Preferably the spherical filler includes a spherical fine filler and a spherical coarse filler. In a method for permanently filling holes in the printed circuit board, the composition is applied to the board so as to fill the holes in the printed circuit board and precured by application of heat. Thereafter, the parts of the precured composition protruding from a surface defining the holes is removed by polishing and then the precured composition is further heated to cause final curing thereof.

Abstract: A liquid thermosetting filling composition comprising (A) an epoxy resin assuming a liquid state at room temperature, (B) a phenolic resin assuming a liquid state at room temperature, (C) a curing catalyst, and (D) an inorganic filler is useful as an ink for permanently filling such holes as via holes and through holes in printed circuit boards of a multilayer board or a double-sided board, a sealing compound for IC packages, and the like. This composition is a two-stage thermally curing type. In a method for permanently filling holes in a printed circuit board, the composition is applied to the board so as to fill the holes in the printed circuit board and precured by application of heat. The parts of the precured composition protruding from a surface defining the holes is removed by polishing and then the precured composition is further heated to cause final curing thereof.