| 摘要 |
PURPOSE:To obtain a lightweight soft polyvinyl chloride molded anticle with excellent wear-resistant property and fine external appearance by a method wherein soft non-crosslinked polyvinyl chloride composition blended with lightweight filler is injection-molded by employing a pinpoint gate under specified conditions. CONSTITUTION:Lightweight polyvinyl chloride composition employing PVC (polyvinyl chloride), the mean degree of polymerization of which is 400-4,000, consists in blending 100pts.wt. of PVC with 30-150pts.wt. of plasticizer and 5- 100pts.wt. of lightweight filler, the specific gravity of which is 0.8 or less, the particle diameter of which is 300mum or less and the compression strength of which is 70kg/cm<2> or above. Said composition is mixed with stabilizer and another additives in a mixer and, after that, filled through a pinpoint gate, the gate crosssectional area of which is 0.5-2mm.<2> and the length of which 1-5mm., into a cavity at the linear speed of molten resin of 5X10<2>-2X10<3>cm/sec in order to obtain a molded part with the minimum thickness of 2mm.. |
