| 摘要 |
PURPOSE:To obtain a more transparent P P sheet by rolling polypropylene (P P) to be a specific drawing ratio at the temperature of a melting point or lower, and rendering the surface smooth thereafter. CONSTITUTION:A polymeric material supplied in a hopper 1 as pellets is continuously extruded by means of an extruder 2 for heating and kneading pellets and the molten resin is cool-solidified as advancing in the inner part of a die 3 and then fully solidified in the proximity of an outlet of the die to be molded as a sheet. In the case of manufacturing a P P sheet by a hot extruding method or the like in this manner, the P P sheet molded to be relatively thick in the aforegoing process is subsequently passed through a rolling machine 6 and the P P is rolled to be a ratio of 3 or more at the temperature of a melting point or lower, after that, of which surface is processed to be made smooth by a surface processing machine 7. In this way, by rolling at the drawing ratio of 3 or more, the grain boundary is allowed to be destroyed to thereby obtain a P P sheet with high transparency. |
