| 摘要 |
<p>PURPOSE:To obtain a vessel formed by drawing having excellent general application and transparency which maintains such transparency even after retort treatment by providing a layer of transparent polypropylene or copolymer of ethylene and propylene containing nucleating agent and a layered structure of resin layers having good surface gloss. CONSTITUTION:For example, in the case of a sheet 1 having a layered structure of polypropylene/adhesives/saponified ethylene-vinylacetate copolymer/adhesives/ polycarbonate, the whole of said sheet can be formed by one process of co- extrusion. Extrusion can be performed at temperatures of 220-280 deg.C. Draw forming is a method in which the sheet 1 is heated to make it soft and the sheet is pressed against a mold. The sheet 1 is heated by a well-known method, such as infrared heater etc., and by heating the sheet to about 150-200 deg.C, it becomes so soft as to allow formation. Method for pressing the sheet against the mold is preferably a plug-assist vacuum formation method. In order to maintain smoothness of the surface of polypropylene or copolymer of ethylene and propylene in pressed contact with the mold and to improve transparency thereof, the mold should have mirror finish.</p> |
