| 摘要 |
PURPOSE:To obtain an optical material low in refractive index, good in transparency, and superior in heat resistance, by copolymerizing a fluorine contg. methacrylate with a fluorine contg. acrylate in a specified ratio. CONSTITUTION:The optical material to be used is a heat resistant polyfluoromethacrylate composed of 70-99mol% repeated units represented by formula I in which R<1>f is 1-3C fluoroalkyl, and 30-1mol% repeated units represented by formula II in which R1, R2 are each H or lower alkyl, and R<2>f is 1-3C fluoroalkyl. Said copolymer is obtd. by copolymerizing fluorine contg. methacrylate represented by formula III, such as trifluoroethyl methacrylate, with fluorine contg. acrylate represented by formula IV, such as trifluoroethyl acrylate in a soln. in bulk using an azo type catalyst. |
