ROLLED POLYESTER SHEET, THERMOFORMED ARTICLE THEREOF AND PRODUCTION THEREOF

摘要

PURPOSE:To obtain a rolled polyester sheet favorable in thermoforming properties by rolling a substantially amorphous polyester sheet to obtain a sheet having specific tensile modulus and reduced to a specific range in thickness irregularity. CONSTITUTION:A rolled polyester sheet is characterized by that tensile modulus in a taking-up direction is 250kg/mm<2> or more and thickness irregularity is + or -8% or less. This sheet can be obtained by rolling a polyester sheet of an amorphous state using rolling rolls 4,5 heated to Tg + or -20 deg.C (Tg; glass transition temp. of polyester) and coated with a lubricant in such a state that the ratio of the rotational speed of the low peripheral speed rolling roll 5 to that of the high peripheral speed rolling roll 4 is set to 0.5-0.8 to reduce the original thickness thereof to 2/3 or less. Further, when the raw sheet is preheated by a preheating roll 3 and further heated to the temp. range of Tg-Tg + 20 deg.C by far infrared rays 7 and rolled by the rolling rolls 4,5 heated to Tg + or -20 deg.C to reduce the original thickness thereof to 3/4 or less, thickness irregularity can be further reduced.