POLYPROPYLENE COMPOSITION WITH IMPROVED MANUFACTURABILITY AND IMPACT Russian patent published in 2023 - IPC C08F10/06 C08L23/10 C08L23/12 C08L23/14 

FIELD: polypropylene products.

SUBSTANCE: present invention is related to a group of inventions: a polypropylene composition for producing packaging products or automotive components; a method for production of a polypropylene composition; product; a packaging item or automotive component; the use of polypropylene composition. This polypropylene composition contains: 60-95 wt.% of the first heterophasic propylene copolymer (A) and 5-40 wt.% of static elastomeric copolymer of ethylene and alpha-olefin (B). The first heterophasic propylene copolymer is characterized by a melt flow index MFI₂ equal to 30-120 g/10 min, and contains 78.0-92.0 wt.% of the crystalline matrix (A1) and 8.0-22.0 wt.% of amorphous propylene-ethylene elastomer (A2). The crystalline matrix (A1) is a homo- or copolymer of propylene, and the specified crystalline matrix corresponds to the crystalline fraction (CF) and contains 0.0-2.0 wt.% of comonomer. The amorphous propylene-ethylene elastomer (A2) optionally contains C₄-C₁₂-alpha-olefin(s) as additional comonomers dispersed in said crystalline matrix (A1), corresponds to the soluble fraction (RF) and contains 15.0-30.0 wt.% of comonomer. Static elastomeric copolymer of ethylene and alpha-olefin (B) is characterized by MFI₂ equal to 0.1-100 g/10 min, and a density of 840-900 kg/m³. The method for producing a polypropylene composition includes the steps of polymerizing the first heterophasic propylene copolymer (A) in a sequential polymerization process in the presence of a single-centre Ziegler-Natta type catalyst system; melt blending of said copolymer (A) with a static elastomeric copolymer of ethylene and an alpha-olefin (B); optionally adding a second heterophasic propylene copolymer (C) polymerized in the presence of a Ziegler-Natta type catalyst system, as well as a reinforcing mineral filler (D) in a melt blending step, followed by solidifying the resulting melt in a strand granulation or underwater granulation step. The product is obtained by injection molding and is characterized by a flexural modulus of 500-1000 MPa, Charpy notched impact strength (NIS) at 23°C of 25.0-95.0 kJ/m², and Charpy NIS at -20°C of 7.0-75.0 kJ/m². The use of a polypropylene composition for production of a packaging article or an automotive component having a wall thickness of at most 1.5 mm in an injection moulding process.

EFFECT: technical result is development of a composition that combines a well-balanced ratio between stiffness and impact strength, low emissions of volatile and hardly volatile substances, and good manufacturability.

15 cl, 1 dwg, 2 tbl, 7 ex