Patent ID: 8147638
Filing Date: 2012-04-03
Classification: C09K,G02B

Abstract:
1. A method of manufacturing a polarizing plate comprising the steps of: (i) casting a dope containing a plasticizer and a cellulose ester on a support to form a web; (ii) peeling the web from the support; (iii) stretching the web while the web still contains a solvent; (iv) further drying the web until an amount of residual solvent decreases to less than 0.3% by weight; (v) heat treating the web at 105-155° C. under a rate of atmosphere replacement of 12 times/h or more while the web is transported, to form a retardation film; (vi) adhering the retardation film to at least one surface of a polarizing film to form a polarizing plate, wherein a free volume radius of the retardation film determined by positron annihilation lifetime spectroscopy is in the range of 0.250-0.310 nm.