| 摘要 |
<p>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 material, wherein the crystalline random propylene copolymer material is a mixture composed of (I) a crystalline random propylene copolymer of a major amount of propylene with a minor amount of anotherα- 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 random copolymer (II) has (A) an intrinsic viscosity [η], 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 W1 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 W2 of less than 4x[η]-1,2 in % by weight based on the weight of the copolymer (II); can be heat-sealed at relatively low temperatures in a broad temperature interval and has a high heat-sealing strength, and the heat-sealing temperature is only increased slightly after a low-temperature heat treatment.</p> |
