Optical film method of manufacture thereof and sheet polarizer

• Main Authors: OKADA YASUMASA, OGINO KENTARO, KOBAYASHI HITOSHI, TABATA HIRONORI, NISHIMURA KATSUMI, NOZATO SHOJI, SAWADA TAKAHIKO
• Format: Patent
• Language: English; Korean
• Published: 15.02.2003
• Edition: 7
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; GENERAL PROCESSES OF COMPOUNDING; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

PURPOSE: Provided are an optical film which exhibits a small residual phase difference and a minimized variation of an optical axis, a method for manufacture thereof, and a sheet polarizer. CONSTITUTION: The optical film is made by melt extrusion using a noncrystalline thermoplastic resin, and has a thickness of below 100 micrometers, a residual phase difference of up to 10 nm and an optical axis deviation within ± 10 deg. The method comprises the steps of (i) extruding a noncrystalline thermoplastic resin having a glass transition temperature(Tg) from an extrusion die into a film, and (ii) bringing the film into close contact with a chill roll, so as to obtain an optical film having a thickness of below 100 micrometers, a residual phase difference of up to 10 nm and an optical axis deviation within ± 10 deg, wherein a temperature of the film just before its contact with the chill roll is maintained at a temperature Tg + 50 deg.C or higher. 본 발명은 비결정성 열가소성 수지의 용융 압출성형을 통하여 제작되고, 두께가 100 ㎛ 미만이고, 잉여 위상차가 10 ㎚ 이하이며 광학 축 편차의 범위가 ±10°이내인 광학 필름, 그리고 광학 필름을 제조하는 방법에 관한 것이며, 유리 전이 온도(Tg)를 갖는 비결정성 열가소성 수지가 압출성형 금형으로부터 필름으로 압출성형되고 이러한 필름이 냉각 롤과 가까이 접촉될 때, 금형 출구로부터 나온 필름이 냉각 롤과 접촉되기 직전의 필름의 온도가 Tg + 50℃ 미만으로 떨어지지 않도록 유지되는 것을 특징으로 한다.