| 摘要 |
<p>Closure comprises: base wall with an inner surface; peripheral skirt extending from the base wall; and liner compression moulded on the inner surface of the base wall, comprising: (a) EVAc compsn. comprising about 85-94 wt.% polyethylene and about 6-15 wt.% vinyl acetate; (b) prim. fatty acid amide selected from an oleamide and an erucamide; and (c) bis-fatty acid amide. Total amt. of prim. fatty acid amide and bis-fatty acid amide is 0.5-1.5 wt.% based on the wt. of the EVAc and the ratio of prim. fatty acid is bis-fatty acid amide is 25:75-75:25. Bis-fatty acid amide is pref. selected from ethylene-bis-oleamide and ethylene-bis-stearamide ADVANTAGE : Plastic closure has uniform removal torques, and is useful in cold climate conditions with migration of the lubricant to the surface of the liner. In an example, compsn. comprises ELVAX 650 (EVAc copolymer, melt flow 8.0 g/10 min, density 0.933 g/cc, 12.0% acetate; 100 pts.wt.), ethylene bis stearamide (0.5 pt.wt.), euracamide fatty acid amide (molecular wt. 335, density at 130 deg. C 0.815 g/ml, density at 160 deg. F 0.851 g/ml, viscosity at 130 deg. C 66.4 cP, heat of fusion 9.8 kcal.mol, flash point 262 deg. C, fire point 287 deg.C; 0.5 pt.wt.), LDPE (30MF; 10 pts.wt.) had a removal torque of 7.8. The removal torque after 1 day was 10, after 1 week it was 13.8 and after 1 week under CO2 it was 3.84. A control example contg. ethylene bis oleamide (1.5 pts.wt.) in place of the ethylene bis stearamide and erucamide had an initial removal torque of 12.0. The removal torque after 1 day was 11, after 1 week it was 15.0 and after 1 week under CO2 it was 3.85.</p> |
