A process for preparing a photochromic lens

• Main Authors: JAMES N. RIECK, PIA SANTELICES, SIVARAM KRISHNAN, WILLIAM G. CURTIS, ROBERT ALLEN PYLES, JACK C. CHAN
• Format: Patent
• Language: English
• Published: 16.07.2001
• Edition: 7
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CONTACT LENSES; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PERFORMING OPERATIONS; PHYSICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURESAS SPECTACLES; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

A process for making a photochromic optical lens is disclosed. In a first embodiment of the process a multi-plied laminate, containing a ply of photochromic thermoplastic polyurethane (herein "TPU") and a ply containing thermoplastic polycarbonate, is first placed in the cavity of a suitable mold. The ply that contains polycarbonate resin is placed facing the cavity. Thermoplastic polycarbonate resin is then injected into the cavity. In a second embodiment, referred to as an over-mold method, polycarbonate is first injection molded into a molding cavity to form a substrate. Photochromic TPU is, in a subsequent step, injected into the cavity to form a superstrate overlay. In both embodiments, the articles thus molded are suitable for the preparation of optical lenses.