| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method of filtering dope which is applied to the production of a cellulose ester film to be utilized in the polarizing plate protective film used in a liquid crystal device (LCD) or the like, has a sufficiently long filtration life while catching fine particle agglomerate, resin undissolved substances and the like which come to foreign substances in the film in the step of filtering the dope containing fine particles, and excels in productivity, and a cellulose ester film which excels as a member of a large screen liquid crystal device and has no failure due to foreign substances. <P>SOLUTION: The method of filtering dope comprises previously filtering a dispersion of fine particles to be added to the dope or previously filtering a dispersion of fine particles to be added to the dope and the other liquid additive, mixing the fine particle dispersion after the previous filtering with the dope or the fine particle dispersion and the liquid additive both after the previous filtration with the dope to prepare fine particle-containing dope, and filtering the fine particle-containing dope with a filtering medium having a particle diameter of 90% collection 10 to 100 times the average particle diameter of the fine particles. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
