| 摘要 |
PURPOSE:To provide a high-quality container having good thermal stability and difficult to cause blushing by a method wherein a polyester container obtained by stretching blow molding is heat-set in a specified temperature range. CONSTITUTION:In the process of producing a polyethylene terephthalate container with eta larger than 0.65 by stretching blow molding, heat setting is conducted in a temperature range of 95-125 deg.C, residual strains in the stretched portion are released before formation of spherulite starts in the unstretched and/or slightly stretched portion, to obtain a container having good thermal stability (factor of shrinkage in boiling water: less than 5%) and unapt to blush. A more favorably effect can be obtained by conducting heat setting with a temperature difference, for example, by keeping the unstretched portions such as the mouth and bottom portions of the container at a temperature of 95-125 deg.C and keeping the other portion at a higher temperature. |
