| 摘要 |
PURPOSE: A method of preparing polypropylene film for packing materials is provided to give good dimensional stability and mechanical property, improve matte property, and give useful component as packing materials. CONSTITUTION: A method comprises mixing polyacryl-based solids of 0.1-1 part by weight and inorganic particles of 0.1-1 part by weight based upon polypropylene of 100 part by weight; extruding the mixture; quickly cooling the extrudate at 0-20deg.C to form sheet; vertically elongating the sheet such that the birefringence absolute value (delta n) is at least 5x10¬-3 and not exceeding 50x10¬-3; and horizontally elongating the sheet such that the birefringence absolute value (delta n) is 35x10¬-3 or less. The polypropylene has melt index of 1-20g/10min and melting point of 140-180deg.C. The particle sizes of the polyacryl-based solids and inorganic particles are 0.1-2micrometer and 0.1-1micrometer, respectively.
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