Copolymer for improving methacrylic resin heat resistance

Abstract

A copolymer for improving heat resistance of a methacrylic resin which can achieve preservation of excellent transparency of the methacrylic resin and improvement in heat resistance, and can provide a molded product having excellent appearance, by adding the copolymer to the methacrylic resin, is provided. According to the present invention, a copolymer for improving heat resistance of a methacrylic resin, including: 45 to 85 mass % of an aromatic vinyl monomer unit; 5 to 45 mass % of a (meth)acrylic acid ester monomer unit; and 10 to 20 mass % of an unsaturated dicarboxylic acid anhydride monomer unit; wherein the copolymer has a total light transmittance of 88% or more, the total light transmittance being measured in accordance with ASTM D1003 for a sample with 2 mm-thickness, is provided.

1 . A copolymer for improving heat resistance of a methacrylic resin, comprising:
 45 to 85 mass % of an aromatic vinyl monomer unit;   5 to 45 mass % of a (meth)acrylic acid ester monomer unit; and   10 to 20 mass % of an unsaturated dicarboxylic acid anhydride monomer unit; wherein   the copolymer has a total light transmittance of 88% or more, the total light transmittance being measured in accordance with ASTM D1003 for a sample with 2 mm-thickness.   
     
     
         2 . The copolymer of  claim 1 , comprising:
 50 to 80 mass % of the aromatic vinyl monomer unit;   8 to 38 mass % of the (meth)acrylic acid ester monomer unit; and   12 to 18 mass % of the unsaturated dicarboxylic acid anhydride monomer unit.   
     
     
         3 . The copolymer of  claim 1 , wherein the weight average molecular weight (Mw) of the copolymer is 10×10 4  to 20×10 4 . 
     
     
         4 . A resin composition, comprising:
 5 to 50 mass % of the copolymer of  claim 1 ; and   50 to 95 mass % of a methacrylic resin.   
     
     
         5 . The resin composition of  claim 4 , wherein the methacrylic resin comprises:
 70 to 100 mass % of a meth(acrylic) acid ester monomer unit; and   0 to 30 mass % of an aromatic vinyl monomer unit.   
     
     
         6 . A molded body comprising a resin composition of  claim 4 . 
     
     
         7 . The molded body of  claim 6 , being an optical part. 
     
     
         8 . The molded body of  claim 7 , being an optical film. 
     
     
         9 . The molded body of  claim 8 , being a polarizing film protecting film, a retardation film, or an antireflection film. 
     
     
         10 . The copolymer of  claim 2 , wherein the weight average molecular weight (Mw) of the copolymer is 10×10 4  to 20×10 4 . 
     
     
         11 . A resin composition, comprising:
 5 to 50 mass % of the copolymer of  claim 2 ; and   50 to 95 mass % of a methacrylic resin.   
     
     
         12 . A resin composition, comprising:
 5 to 50 mass % of the copolymer of  claim 3 ; and   50 to 95 mass % of a methacrylic resin.   
     
     
         13 . A resin composition, comprising:
 5 to 50 mass % of the copolymer of  claim 10 ; and   50 to 95 mass % of a methacrylic resin.   
     
     
         14 . A molded body comprising a resin composition of  claim 2 . 
     
     
         15 . A molded body comprising a resin composition of  claim 3 . 
     
     
         16 . A molded body comprising a resin composition of  claim 10 . 
     
     
         17 . A molded body comprising a resin composition of  claim 11 . 
     
     
         18 . A molded body comprising a resin composition of  claim 12 . 
     
     
         19 . A molded body comprising a resin composition of  claim 13 .