| 摘要 |
PURPOSE:To make it possible to obtain a product, which has little residual strain even in a blow molded article produced by halving and in which dimensional accuracy is requested. CONSTITUTION:In the manufacturing method of a synthetic resin blow-molded article, by halving a blow molded article symmetrical products are obtained at after-working, the blow-molded article is made so as to have multi-kind and multi-layered structure under the condition that the difference between the shrinkage factors of inner surface material and of outer surface material is set to be 5/1,000-20/1,000 and the ratio of their wall thicknesses is set to be 10/90-90/10. |
