Heat-sealable plastics laminate.

摘要

A crystalline random propylene copolymer composition suitable for use in a heat-sealable laminate comprising also a crystalline propylene polymer substrate layer, comprises (i) a crystalline random propylene copolymer comprising 99 to 85 mole% of propylene and 1 to 15 mole% of an alpha-olefin other than propylene and (ii) a random 1-butene copolymer comprising 1-butene and an alpha-olefin having at least 5 carbon atoms, the weight ratio of copolymer (i) to copolymer (ii) being from 5:95 to 90:10 and said random 1-butene copolymer (ii) satisfying the following conditions:
<UnorderedLists id="ula01" listStyle="none"><ListItem>(A) it comprises 50 to 99 mole% of the 1-butene component and from 50 to 1 mole% of the alpha-olefin,</ListItem><ListItem>(B) it has an intrinsic viscosity [η], measured in decalin at 135°C, of from 0.5 to 6 dllg,</ListItem><ListItem>(C) it has a melting point [Tm], measured by a differential scanning calorimeter, of from 30 to 120°C,</ListItem><ListItem>(D) it has a crystallinity, measured by X-ray diffractometry, of from 5 to 60%,</ListItem><ListItem>(E) the amount [W<Sub>1</Sub>, in % by weight] of that portion of it which is soluble in boiling methyl acetate is not more than 2%, and</ListItem><ListItem>(F) the amount [W<Sub>z</Sub> in % by weight] of that portion of it which is soluble in a 1:1 by volume mixture of acetone and n-decane at 10°C is 5 x [η]<Sup>-1.2</Sup> or less.</ListItem></UnorderedLists>