PRODUCTION OF MOLDING POLYMER COMPOSITION

PURPOSE:To obtain a 1-methyl-4-ethenylbenzene polymer composition capable of forming moldings excellent in appearance and transparency, by adjusting the amount of solvent-insoluble components in a resin composition to a value within a specified range and polymerizing the monomer. CONSTITUTION:In producing a polymer composition containing a polymer comprising at least 30wt% monomer mixture comprising at least 85wt% 1-methyl-4- ethenylbenzene, 0-0.1wt% 1-methyl-2-ethenylbenzene, and 0-15wt% 1-methyl-3- ethenylbenzene, and 0-70wt% monomer copolymerizable with the monomer mixture (e.g., acrylonitrile, methacrylic acid, or styrene); the amount of tetrahydrofuran-insoluble component in the composition is adjusted to 0.0005-0.010 wt%, based on the composition. A molding polymer composition capable of forming transparent moldings of markedly improve appearance can be obtained, and it can be used in, for example, electric parts such as record player dust covers and fan impellers, or as an optical resin material.