| abstract |
1,126,034. Drawing sheet material. GLANZSTOFF A.G. 2 Dec., 1965 [3 Dec., 1964], No. 51244/65. Heading B5A. A process for the production of an article from polyethylene terephthalate having a solution viscosity between 1À4 and 1À7 and a degree of crystallization of 0% to 25% comprises heating a plate or film of said material to a temperature between 75‹ and 180‹ C., shaping the heated plate or film by vacuum deepdrawing and immediately after the shaping, cooling the resultant article in the mould to a temperature below 70‹ C. The vacuum deepdrawing may be effected using a male or female mould assisted by mechanical or pneumatic pre-stretching if desired. The plate or film is advantageously heated by infra-red radiations and the formed article is cooled preferably by blasts of a cold inert gas. |