| 摘要 |
PURPOSE:To manufacture a film with a high strength, which is suitable for use in a high temperature, by a method wherein, a share rate in the temperature die of a die, the surface temperature of a casting drum and the rate of draft are controlled and polyester with a specified principal chain is employed. CONSTITUTION:A film is manufactured by thermotropic crystalline polyester so as to satisfy following conditions A, B, C, D; i.e. A; the temperature of a die should be higher than the softening point of the polyester by 30 deg.C or more. B: the share rate at a die section should be 200sec<-1> or lower. C; the surface temperature of a casting drum should be lower than the softening point of the polyester by 30 deg.C or more and higher than the glass transition point of the same. D: a draft rate should be 2 or more. The optimally employed thermotropic crystalline polyester consists of two constituting units usually and the first unit contains the unit shown by a formula (I) by 5-95mol%. In the formula (1) Ar<1> shows a trivalent aromatic group. The second unit consists of the group of oxycarboxylic acid shown by the formula (II) and Ar<2> shown a bivalent aromatic group. |
