| 摘要 |
PURPOSE:To provide a biaxially oriented smooth polyester film markedly improved in lubricity and wear resistance, incorporated with respective specified amounts of fine rutile type titanium dioxide of specific particle size and coarse anatase type titanium dioxide of specific particle size. CONSTITUTION:The objective biaxially oriented film can be obtained from a polyester prepared by incorporating, during the production process of the polyester (pref. having >=80mol% of ethylene terephthalate unit and/or ethylene -2,6-naphthalate unit), pref. after the ester interchange reaction or esterification and before the polycondensation, (A) 0.01-1(pref. 0.1-0.7)wt% of a rutile type titanium dioxide with an average particle size 0.01-0.3(pref. 0.05-0.27)mum and Mohs hardness 6-7 and (B) 0.002-0.5(pref. 0.005-0.3)wt% of an anatase type titanium dioxide with an average particle size 0.31-1(pref. 0.4-0.7)mum and Mohs hardness 5.5-6. |
