Patent ID: 9631033
Date: 2017-04-25
CPC Classifications: C07D,C08C,C08F,C08L

Claim:
1. A copolymer composition obtained by copolymerizing an N-phenylmaleimide compound and one or more other monomers or resins copolymerizable with the N-phenylmaleimide compound, wherein the N-phenylmaleimide compound comprises 0.005 to 0.08% by weight of N-(2,5-dioxo-1-phenyl-3-pyrrolidinyl)-N-phenylmaleamic acid (PPMA) and 0.01 to 0.08% by weight of N-phenylfumaramic acid (PFA), wherein the contents of the PPMA and PFA are measured using a high-performance liquid chromatography under conditions as below: Mobile phase: a mixed solution of an aqueous solution of potassium dihydrogen orthophosphate (0.0085 mol/l) and methanol (mixing ratio: 2.4/1.0 (wt/wt)) adjusted to a pH of 3.7 with orthophosphoric acid; Column temperature: 45° C.; Flow rate: 0.8 ml/min.