| 摘要 |
A method is disclosed of manufacturing, by biaxial stretch blow moulding, a hollow article of polypropylene, such as a bottle which is transparent and has luster and a uniform wall thickness as a whole. In the method, fully mixed and blended molten polypropylene is injected into a parison mould to form a parison, and the parison is removed from the parison mould as soon as possible, whilst only a surface layer has cooled sufficiently to form a skin. The parison is transferred immediately to the cavity of a temperature control device, where the parison is subjected briefly to a preliminary stretching and blowing to expand it into contact with the surface of the cavity. The parison is then allowed to contract again and is transferred to a blow mould where it is subjected to a conventional stretch blow moulding process to produce the desired hollow article. |
