Laminated structure comprising a substrate layer composed of a crystalline propylene resin and a heat-sealable layer composed of a crystalline propylene random copolymer composition

Abstract

A laminated structure comprising a substrate layer of a crystalline propylene resin and, positioned in direct contact with at least one surface of said substrate layer, a heat-sealable layer of a crystalline random propylene copolymer composition, wherein the crystalline random propylene copolymer composition is a mixture composed of (I) a crystalline random propylene copolymer of a major amount of propylene with a minor amount of another alpha-olefin, and (II) a random copolymer consisting essentially of more than 60 to 99 mole % of 1-butene and less than 40 to 1 mole % of propylene, the weight ratio of (I)/(II) being from 5/95 to 90/10, and the radom copolymer (II) has (A) an intrinsic viscosity [.eta.], determined in decalin at 135.degree. C., of 0.5 to 6 dl/g, (B) a DSC melting point (Tm), measured by a differential scanning calorimeter, of 50 to 130.degree. C., (C) a degree of crystallinity, measured by X-ray diffractometry, of 5 to 60%, (D) a boiling methyl acetate-soluble content (W.sub.1) of not more than 2% by weight based on the weight of the copolymer (II), and (E) an n-decane/acetone (1:1 by volume) mixture-soluble content (W.sub.2) of less than 4.times[eta]sup.-1.2 in % by weight based on the weight of the copolymer (II); and a crystalline random propylene copolymer composition used for the said laminated structure.

Dependencies are inferred from the claim text.