abstract |
This maleimide-based copolymer contains 40-60 mass % of aromatic vinyl monomer units, 5-20 mass % of vinyl cyanide monomer units, and 35-50 mass % of maleimide monomer units, and is such that a 4 mass % tetrahydrofuran solution of the copolymer has a transmittance of 90% or more for light having a wavelength of 450 nm at an optical path length of 10 mm, and the residual maleimide-based monomer amount is less than 300 ppm. This maleimide-based copolymer preferably further contains 0-10 mass % of unsaturated dicarboxylic acid anhydride monomer units, and preferably has a glass transition temperature of 165° C. or higher. |