| 摘要 |
PURPOSE:To improve weatherability and to allow easy production by using a specific polymer as a core, allowing butyl acetate to exist in this core and specifying the concn. thereof to <=1,000ppm. CONSTITUTION:The polymer which consists of a homomonomer of methyl methacrylate or a copolymer of this monomer and other monomer which can copolymerize with the methyl methacrylate and has 80,000 to 200,000 weight average mol. wt. is used as the core and the polymer having the refractive index lower than the refractive index of this core is used as a sheath. The butyl acetate is made to exist in this core and the concn. thereof is specified to <=1,000ppm. The core polymer is exemplified by acrylate, such as methyl acrylate and ethyl acrylate, and methacrylate, such as ethyl methacrylate, as the monomer copolymerizable with the methyl methacrylate, in addition to the homopolymer of the methyl methacrylate. The weatherability is improved and the production is facilitated in this way. |
