Sodium benzoate as a nucleating agent for uniaxially oriented polypropylene film

摘要

PURPOSE: To decrease the shrinkage of a monoaxially oriented polypropylene film and increase the crystallinity thereof. ;CONSTITUTION: This invention relates to 1) polypropylene contg. sodium benzoate in a concn. of 1,000 ppm or lower, 2) a monoaxially oriented polypropylene film contg. sodium benzoate, and 3) a process for preparing a monoaxially oriented polypropylene film comprising (1) mixing sodium benzoate at a level of 1,000 ppm into polypropylene, (2) plasticizing the resultant mixture in an extruder, (3) extruding the mixture through a flat sheet die, (4) quenching the resultant polypropylene sheet, and (5) stretching the sheet at the m.p. of polypropylene or lower in the machine direction by a stretching ratio of at least about 4:1.;COPYRIGHT: (C)1995,JPO