PREPARATION OF POLYESTER HOLLOW FORMED BODY

摘要

Disclosed is a process for the preparation of a heat-resistant polyester hollow formed body, which comprises mounting a preform of a thermoplastic polyester composed mainly of ethylene terephthalate units, which is maintained at a temperature where highspeed drawing is possible but whitening can be prevented, especially at a temperature represented by the following formula: T = k(100?IV - 8?DEG + 42) (1) wherein IV stands for the intrinsic viscosity (d?/g) of the thermoplastic polyester, DEG stands for the content (% by weight) of diethylene glycol units in the thermoplastic polyester, k is a number of from 0.95 to 1.05, and T stands for the temperature ( C) of the preform, in a hollow forming mold maintained at a temperature as high as possible within the range where a final hollow formed body can be withdrawn without deformation substantially wider non-cooling, blowing air maintained at a temperature higher than the preform temperature into the preform to effect stretch drawing and expansion drawing so that the drawing speed in the axial direction is at least 250%/sec and the drawing speed in the circumferential direction is at least 450%/sec, and effecting heat setting while the preform is being drawformed. According to this process, a polyester hollow formed vessel excellent in the resistance to thermal contraction can be prepared at a very high manufacturing speed.