METHOD FOR MANUFACTURING OPTICAL FILM

• Main Author: OGINO KENTARO
• Format: Patent
• Language: English
• Published: 25.11.2004
• Edition: 7
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

PROBLEM TO BE SOLVED: To provide a thin optical film which is free from surface defects such as fish eye and made of an amorphous thermoplastic resin, and a method for manufacturing the optical film. SOLUTION: In this method, when an amorphous thermoplastic resin film with a thickness of not more than 100 μm which is extruded in the form of a sheet from a die mounted on an extruder, is closely attached to a cooling roll, the film is gripped under pressure between a touch roll having a resiliently deformable surface which has a surface roughness Ry of not more than 0.5 μm and a temperature controlled to a glass transition temperature (Tg) of -10 to 40 °C of an amorphous thermoplastic resin and the rigid cooling roll. In addition, the fish eye-like defect showing the nuclear size of not more than 50 μm and the extrusion direction (MD)length of not more than 200 μm can be reduced to not more than 30 μm and not more than 50 μm respectively. The amorphous thermoplastic resin is preferably a norbornene resin. COPYRIGHT: (C)2005,JPO&NCIPI