Film-forming composition
AssigneeImperial Chemical Industries PLC
InventorsRobert C. Lansbury, Thomas G. Heggs
Life of this patent
Estimating the term…
Abstract
A film-forming composition comprising a copolymer of propylene with an alpha-olefin containing from 4 to 10 carbon atoms, the copolymer containing from 80 to 95% by weight of propylene, and from 25 to 90% by weight of the composition of a second homo- or co-polymer of a similarly defined alpha-olefin. The composition is particularly suitable for the production of heat-sealable, multiple-layer films having a polypropylene core.
Claims5
A multiple-layer film comprising a substrate layer of a homo- or co-polymer of an alpha-olefin the molecule of which contains from 2 to 6 carbon atoms, said substrate layer having a first and a second surface, and, on at least one of said surfaces of the substrate, a heat sealable layer formed from a composition comprising a blend of
- (a) a substantially crystalline copolymer of propylene with an alpha-olefin containing from 4 to 10 carbon atoms in its molecule, the propylene content of the copolymer being from 80 to 95% by weight of the copolymer, and
- (b) a second polymer comprising a homopolymer of an alpha-olefin containing from 4 to 10 carbon atoms in its molecule or a substantially crystalline copolymer in which said alpha-olefin is copolymerised with up to 10% by weight, based on the weight of the copolymer, of an alpha-olefin containing from 2 to 10 carbon atoms in its molecule,
- the second polymer constituting from 25 to 90% by weight of the composition.
A biaxially oriented multiple-layer film comprising a substrate layer of a propylene homopolymer or a copolymer of propylene with from 0.5 to 10% of ethylene by weight of the copolymer, said substrate layer having a first and a second surface, and, on at least one of said surfaces of the substrate, a coextruded heat sealable layer formed from a blend comprising from 65 to 35% by weight of a propylene/butene-1 substantially crystalline random copolymer containing from 10 to 15% of butene-1 by weight of said random copolymer, and from 35 to 65% by weight of a substantially crystalline butene-1 homopolymer.
Dependencies are inferred from the claim text.