Patent ID: 9487679
Filing Date: 2016-11-08
CPC Classification: C08K,C08L,C09J,Y10T

Claim Text:
1. A method of producing an acrylic adhesive tape including a release film substrate and an acrylic adhesive layer formed thereon, the method comprising the following steps (a) to (d): step (a) of irradiating a solvent-free photo-polymerizable monomer composition containing an acrylic monomer and a photopolymerization initiator with ultraviolet rays to produce an acrylic polymer A from the acrylic monomer by photopolymerization, the acrylic polymer A having a weight average molecular weight of 700,000 to 3,000,000 when a cross-linking agent is absent, to thereby prepare a polymer syrup containing the acrylic polymer A and an unreacted portion of the acrylic monomer; after preparing the polymer syrup in step (a), step (b) of mixing an adhesion-imparting polymer having a weight average molecular weight of 2,000 to 10,000 with the polymer syrup to prepare an adhesive coating solution, after preparing the adhesive coating solution in step (b), step (c) of applying the adhesive coating solution to the release film substrate to form an adhesive coating film; and after forming the adhesive coating film in step (c), step (d) of irradiating the adhesive coating film with ultraviolet rays to produce an acrylic polymer B from the unreacted portion of the acrylic monomer in the adhesive coating film by photopolymerization, the acrylic polymer B having a weight average molecular weight of 350,000 to 650,000 when a cross-linking agent is absent, to thereby form an acrylic adhesive layer having a molecular weight distribution of 2.4 to 4.4.