| 摘要 |
A molten film extruded from a slot die onto a take-off drum in a cooling system is first cooled on the circumferential surface of the take-off drum and by the ambient air, is subsequently passed into the water bath of a water trough in which the take-off drum is immersed, and finally is transferred from the water bath of the water trough into a post-cooling water bath, in which the film solidifies to an intermediate film having a desired final temperature of approximately 40 DEG C. When the film leaves the take-off drum, the partially solidified molten film has a mean temperature Tu of between 100 DEG C. and 120 DEG C. For optimization of the dwell time of the molten film in the cooling system and in the post-cooling water bath, the drum diameter D of the take-off drum and the length L of the post-cooling water bath are determined by a specific relationship. |
