Lactone ring-containing polymer having few foreign matters and not easily causing gelation, and its applications

摘要

The lactone ring-containing polymer of the present invention meets the following conditions that: (1) the content of polymer gels of 50 µm or greater in average particle diameter is lower than or equal to 100 pieces/100 g, and the weight average molecular weight of the polymer is 50,000 to 170,000; and/or (2) an increasing rate of viscosity after heated at 280°C for 30 minutes is 2.0 times or smaller. The lactone ring-containing polymer of the present invention contains very few foreign matters and does not easily cause gelation, in addition to being excellent in transparency and heat resistance as well as having the desired properties such as mechanical strength and forming and processing properties. The forming material obtained by heating and granulating such a polymer is suitable for use in, for example, optical components such as light guide materials, optical lenses, and optical films.