MANUFACTURE OF POLYPROPYLENE BAND

摘要

PURPOSE:To elevate the firmness and fusing strength with a higher drawing ratio by a method wherein polypropylene with peroxide added thereto is heat treated in an extruder to change the melt frow rate thereof before and after the treatment. CONSTITUTION:Peroxide is added to high molecular polypropylene with the melt flow rate of 0.3-3g/10min and heat treated in an extruder to change the melt flow rate thereof before and after the treatment to MFRAg/10min or MFRB/ 10min so that log10[MFRB]-log10[MFRA] gives 0.2-2. The polypropylene thus obtained is used. The material is melted and extruded in a sheet, cooled and then, stretched. The said peroxide is preferably organic peroxide which has the half-life of 1min in temperature near the melting temperature of a crystaline polypropylene and blended preferably at the rate of 0.002-0.1pts.wt with respect to 100pts.wt. of polypropylene.