| abstract |
(Meth) acrylic acid ester monomer unit (A) in an amount of 50 to 97 mass% and at least one monomer selected from the group consisting of a maleimide structural unit, a glutaric anhydride structural unit, a glutarimide structural unit, and a lactone ring structural unit (B) and 3 to 30 mass% of a vinyl monomer unit (C) copolymerizable with the methacrylic acid ester monomer, and the gel puffy Wherein the methacrylic resin (I) has a weight average molecular weight of from 650,000 to 300,000 as measured by gel permeation chromatography (GPC). |