PRODUCTION OF UNSATURATED POLYESTER RESIN

摘要

PURPOSE: To produce an unsaturated polyester or an unsaturated polyester resin from polyethylene terephthalate(PET) reclaimed from a magnetic recording material in which PET is used as the support. CONSTITUTION: 20-70mol% (one mol is defined as the molecular weight of a repeating unit) polyethylene terephthalate reclaimed by peeling the magnetic layer from a magnetic recording material in which polyethylene terephthalate is used as the support is depolymerized with 80-30mol% glycol, and the product of depolymerization is reacted with a necessary amount of anα,β-unsaturated polybasic acid or an anhydride thereof to a desired degree of esterification.