| 摘要 |
<p>A polyester film characterized by having many uneven units on its surface, each of said uneven units being composed of a fine projection and a depression existing therearound, and a process for producing aforesaid polyester film, which comprises pre-heating an unstretched polyester film containing internal particles attributed to an inert additive having an average particle diameter of 0.05 to 5 mu m and/or a catalyst residue to a temperature of 80 DEG to 120 DEG C.; stretching the film in a first axial direction to 2.6 to 3.5 times at a temperature of 110 DEG to 145 DEG C.; thereafter, stretching the film in a second axial direction at right angles to the first axial direction to 3.0 to 4.0 times at a temperature of 100 DEG to 150 DEG C.; and then heat-setting the stretched film at a temperature of 160 DEG to 240 DEG C.</p> |
