Patent ID: 11904580
Assignee: BOREALIS AG
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC B  C | IPC B  C

Claim 0:
1. A multilayer blown film comprising at least two layers (A) and (B) and one core layer (C) located between layer (A) and (B), wherein layer (A) comprises a Ziegler Natta catalyzed heterophasic propylene copolymer (HECO) and layer (B) comprises a metallocene catalyzed propylene based random copolymer (PRC), wherein:
said heterophasic propylene copolymer (HECO) of Layer A comprises;
a) 75.0 to 95.0 wt. % of a polypropylene matrix (PP-M) with an MFR2 (ISO 1133, 230° C., 2.16 kg) of 0.8 to 10.0 g/10 min being a homopolymer or a copolymer which has an alpha-olefin comonomer content of less than 2.0 wt. %,
b) 5.0 to 25.0 wt. % of an elastomeric propylene-ethylene copolymer (EPC) dispersed in said matrix (PP-M) and
c) 0.0 to 0.5 wt. % of one or more alpha-nucleating agent(s) (NA), and is produced in the presence of a Ziegler Natta catalyst, the heterophasic propylene copolymer (HECO) having
(i) a melt flow rate MFR2 measured according to ISO 1133 (230° C., 2.16 kg load) in the range of 0.3 to 5.0 g/10 min;
(ii) a melting temperature measured with DSC according to ISO 11357-3 in the range of 160° C. to 170° C.
(iii) a xylene cold soluble (XCS) fraction determined according to ISO 16152 (25° C.) in the range of 5.0 to 25.0 wt. % based on the total weight of the heterophasic propylene copolymer (HECO); the xylene cold soluble (XCS) fraction having
an intrinsic viscosity (IV) of 0.8 to 2.8 dl/g;
an ethylene content in the range of 10.0 to 45.0 wt. %,
(iv) a total ethylene content in the range of 1.0 to 10.0 wt. %,
said propylene based random copolymer (PRC) of Layer B comprises
(i) alpha-olefin comonomers selected from ethylene and/or 1-butene in a total amount of 2.0 to 8.0 wt. %;
(ii) a melting temperature measured with DSC according to ISO 11357-3 in the range of 115° C. to 140° C.
and is produced in the presence of a metallocene catalyst,
and wherein the core layer (C) comprises either the Ziegler Natta catalyzed heterophasic propylene copolymer (HECO) or the metallocene catalyzed propylene based random copolymer (PRC).