Pressure-sensitive adhesive having its adherence lost by actinic energy radiation, adhesive sheet having its adherence lost by actinic energy radiation obtained by application of the pressure-sensitiv

A pressure-sensitive adhesive having its adherence lost by actinic energy radiation, comprising an etching-resistant photopolymerization initiator, an actinic energy radiation reactive compound and a hardening agent. Further, there is provided a process for producing an etched metallic material, comprising the steps of: (1) adhering a metal foil to a base film by means of the above pressure-sensitive adhesive having its adherence lost by actinic energy radiation; (2) performing selective etching of the metal foil to thereby obtain an etched metal layer; (3) combining the etched metal layer of the laminate composed of the base film, pressure-sensitive adhesive having its adherence lost by actinic energy radiation and etched metal layer with an insulating substrate; and (4) detaching the base film from the etched metal layer, wherein exposure to actinic energy radiation is carried out at least once after the step (1) but prior to the step (4).