Patent ID: 9090803
Filing Date: 2015-07-28
Classification: C08F,C09J

Abstract:
1. An acrylic pressure sensitive adhesive composition for polarizing film comprising (meth)acrylic copolymers including alkyl(meth)acrylic acid ester monomer having 1 to 12 carbon atoms of alkyl group and a multifunctional crosslinking agent, wherein the meth(acrylic) copolymers comprise an acrylic polymer for crosslinking structure and an acrylic polymer for non-crosslinking structure, wherein the meth(acrylic) copolymers and the multifunctional crosslinking agent form a pressure sensitive adhesive composition including a compact crosslinking structure and a free polymer having no crosslinking structure by a crosslinking reaction, the free polymer having no crosslinking structure being the acrylic polymer for non-crosslinking structure, the crosslinking structure being defined by the gel content represented by the following formula (1) of 21 to 33% and the swelling ration represented by the following formula (2) of 60 to 105, wherein the free polymer having no crosslinking structure has the weight average molecular weight of 1,250,000 to 1,720,000, wherein the free polymer has the ratio of weight average molecular weight and number average molecular weight of 3 to 5.5, wherein the acrylic polymer for non-crosslinking structure has no crosslinkable functional group: wherein A represents the weight of the pressure sensitive adhesive composition including the crosslinking structure and the free polymer, B represents the dry weight of insoluble content of the pressure sensitive adhesive composition including the crosslinking structure and the free polymer after dipping in ethyl acetate at ambient temperature for 48 hours, and C represents the weight of insoluble content which is swollen by ethyl acetate after dipping in ethyl acetate at ambient temperature for 48 hours (weight of insoluble content of pressure sensitive adhesive composition including the crosslinking structure and the free polymer + weight of permeated solvent), and wherein the gel content and swelling ratio satisfy the following formula (3): wherein x represents gel content, and y represents swelling ratio.