Container lid having oxygen shielding properties

Abstract

An oxygen-shielding container lid according to the present invention comprises a high density polyethylene cap shellhaving a skirt sectionand a top plate sectionprovided with an inner ringfor intimate contact with an inner surface of a container mouth; and an in-shell molded bodyprovided in a portion of an inner surface of the top plate section which is surrounded with the inner ring. The in-shell molded bodyis composed of a primary molded bodywhich has been formed by in-shell molding on the inner surface of the top plate section and which has an oxygen shielding function; and a secondary molded bodywhich has been formed on the primary molded bodyby in-shell molding so as to cover the primary molded bodyand to be fused and fixed to the inner surface of the top plate section at the peripheral edge of the primary molded body. A resin composition used for formation of the secondary molded bodycontains linear low density polyethylene, and has a melt flow rate at 190° C. of 1 to 10 g/10 minutes, a density of 0.900 to 0.920 g/cm, and a nominal tensile strain at break, as defined by JIS K-6922-2, of 400% or more.