PROCESS FOR PREPARING OPTICAL THERMOPLASTIC URETHANE RESIN LENSES AND LENSES PREPARED THEREBY

摘要

A process for continuously preparing lenses excellent in various optical properties which are free from variation over the whole lenses, and lenses prepared by the method. The first step of forming a thiourethane prepolymer and the second step of reacting the thiourethane prepolymer with at least one urethane forming monomer are carried out in an extruder or a reactor provided in a later step with an extruder. The extruded optical thermoplastic thiourethane-urethane copolymer is spread into a sheet and stamped out to form a lens precursor, which is then pressed so that a predetermined curved surface is imparted to at least one side of the lens precursor.