Method for reducing cycle time and improving molded part impact energy and ESCR of linear high density polyethylene using a blend of two linear polyethylenes of different densities

摘要

The crystallization half-time and mold cycle time of high density ( 0.935 g/cm.sup.3) polyethylene are reduced and the impact energy is improved by blending two linear ethylene polymers differing in density by 0.015 to 0.150 g/cm.sup.3, to achieve a density similar to a single high density polyethylene. Both polymer components and resulting blend have a melt flow ratio (MFR) of less than 35 which indicates a relatively narrow molecular weight distribution. Articles are formed which do not show the severe warpage experienced with conventional nucleating agents, and which exhibit impact properties superior to a similar single high density polyethylene copolymer.