Abstract: The present invention relates to a double-sided pressure-sensitive adhesive tape or sheet for wiring circuit board, which comprises a pressure-sensitive adhesive layer formed by a pressure-sensitive adhesive composition containing an acrylic polymer and a chain transfer substance, in which the pressure-sensitive adhesive layer has characteristics that a gel fraction in the initial stage is from 40 to 70% by weight, and a difference between a gel fraction (% by weight) of the pressure-sensitive adhesive layer after the following solder reflow step and the gel fraction (% by weight) of the pressure-sensitive adhesive layer in the initial stage is 10 or less. The solder reflow step satisfies the following heat treatment conditions. Surface temperature of the double-sided pressure-sensitive adhesive tape or sheet reaches 175±10° C. within 130 to 180 seconds, the surface temperature reaches 230±10° C. within 200 to 250 seconds, the surface temperature reaches 255±15° C.

Abstract: A wiring circuit board at least contains an electric insulator layer and an electric conductor formed on the electric insulator layer so as to form a predetermined circuit pattern, which further comprises an adhesive layer formed by thermal hardening of the thermosetting adhesive and pressure-sensitive adhesive composition as described in the specification.

Abstract: The present invention relates to a double-sided pressure-sensitive adhesive tape or sheet for wiring circuit board, which comprises a pressure-sensitive adhesive layer formed by a pressure-sensitive adhesive composition containing an acrylic polymer and a chain transfer substance, in which the pressure-sensitive adhesive layer has characteristics that a gel fraction in the initial stage is from 40 to 70% by weight, and a difference between a gel fraction (% by weight) of the pressure-sensitive adhesive layer after the following solder reflow step and the gel fraction (% by weight) of the pressure-sensitive adhesive layer in the initial stage is 10 or less. The solder reflow step satisfies the following heat treatment conditions. Surface temperature of the double-sided pressure-sensitive adhesive tape or sheet reaches 175±10° C. within 130 to 180 seconds, the surface temperature reaches 230±10° C. within 200 to 250 seconds, the surface temperature reaches 255±15° C.

Abstract: A wiring circuit board at least contains an electric insulator layer and an electric conductor formed on the electric insulator layer so as to form a predetermined circuit pattern, which further comprises an adhesive layer formed by thermal hardening of the thermosetting adhesive and pressure-sensitive adhesive composition as described in the specification.

Abstract: A thermosetting adhesive and pressure-sensitive adhesive composition containing 100 parts by weight of an acrylic polymer (X) containing, as monomer components, a (meth)acrylic acid alkyl ester (a) where the alkyl group has 2 to 14 carbon atoms in an amount of 60 to 75% by weight relative to the total amount of monomer components, a cyano group-containing monomer (b) in an amount of 20 to 35% by weight relative to the total amount of monomer components, and a carboxyl group-containing monomer (c) in an amount of 0.5 to 10% by weight relative to the total amount of monomer components and 1 to 20 parts by weight of a carbolic acid-based resorcinol-type phenol resin (Y) represented by the following formula (1), and further containing an ultraviolet absorbent (Z). wherein R1 represents —CH2— or —CH2—O—CH2—, n is a positive integer, and m is an integer of 1 to 4.