POLYETHYLENE-BASED CONTAINER CAP

摘要

PROBLEM TO BE SOLVED: To provide a polyethylene-based container cap excellent in gas barrier property, particularly, oxygen permeation preventing property, as well as excellent in various characteristics such as molding property, appearance of a molded product, mechanical strength and heat resistance, further excellent in recycling property, particularly in classification property in a recycling process of PET bottles.

SOLUTION: The polyethylene-based container cap comprises an organized layered silicate (A) by 5 to 30 wt.% and a polar group-containing polyethylene (B) by 70 to 95 wt.% having density of 0.920 to 0.972 g/cm3and a melt flow rate (MFR) of 1 to 100 g/10 min measured at 190°C under a load of 2.16 kg, and satisfies the following characteristics (1) to (4). The cap has (1) density from 0.940 to 0.998 g/cm3; (2) a ratio (η48/η3100) ranging from 7 to 30, of viscosity η48(Pa s) measured at a shear rate of 48 sec-1to viscosity η3100(Pa s) measured at a shear rate of 3,100 sec-1at 190°C by a capillary rheometer; (3) a ratio P/P0of not more than 0.7 of an oxygen permeation coefficient P (cm3×mm/m2×24 hr×atm) (at 23°C and 65% RH) of the polyethylene-based container cap to an oxygen permeation coefficient P0(cm3×mm/m2×24 hr×atm) (at 23°C and 65% RH) of the polar group-containing polyethylene (B) as the main component of the polyethylene-based container cap; and (4) a flexural modulus of not less than 900 MPa.

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