PRODUCTION OF POLYSULFONE RESIN FILM

摘要

PROBLEM TO BE SOLVED: To produce a polysulfone resin film having excellent clarity and surface smoothness required of an optical film stably at a high productivity without the necessity for the filtration of a resin soln. by using an amide compd. as a polymn. solvent in producing a polysulfone resin for film formation. SOLUTION: The amide compd. used is an aliph. amide of formula I (wherein R<1> to R<3> are each a 1-6C hydrocarbon group) or formula II (wherein R<1> to R<4> are each a 1-6C hydrocarbon group)(e.g. N,N-dimethylacetamide) or an alicyclic amide of formula II (wherein R<1> is a 1-6C hydrocarbon group; and (n) is 1-6) or formula IV (wherein R<1> and R<2> are each a 1-6C hydrocarbon group; and (n) is 1-6)(e.g. N-methyl2-pyrrolidone). The amt. of the compd. used is 0.05-30 times that of a dihydric phenol used. The polymn. is conducted usually at 80-400 deg.C for 30 min to 24 hr. A soln. of the resin having the viscosity adjusted is cast on a glass substrate to produce a film.