Heterophasic polypropylene with high impact properties

Abstract

The present invention relates to a heterophasic polypropylene resin comprising a polypropylene homo- or copolymer matrix phase (A) and an ethylene-propylene copolymer phase (B) dispersed within the matrix, wherein the heterophasic polypropylene resin has a fraction insoluble in p-xylene (XCU) at 25 DEG C with an intrinsic viscosity of 2.0 dl / g or less, determined according to DIN EN ISO 1628-1 and -3, and a fraction soluble in p-xylene (XCS) at 25 DEG C having an intrinsic viscosity of 2.0 to 4.5 dl / g, determined according to DIN EN ISO 1628-1 and -3, and an amount of ethylene monomer units of 60 to 85 mol%, a heterophasic polypropylene composition comprising such a resin, a process for preparing that resin, and an article made thereof.

Description

technical field [0001] The present invention relates to a heterophasic polypropylene resin, which comprises a propylene homopolymer or copolymer matrix and an ethylene-propylene copolymer phase dispersed in the matrix, and has excellent impact resistance. In addition, the invention also relates to a method for the manufacture of such a polypropylene resin and the use of such a resin for the manufacture of articles. Background technique [0002] Known commercial polypropylenes are typically isotactic, semi-crystalline, thermoplastic polymer materials with an excellent cost performance ratio. However, their brittleness under impact loading at high speeds and especially at low temperatures limits their application as engineering thermoplastics. [0003] A known method of improving the toughness of isotactic polypropylene is to incorporate an ethylene-propylene copolymer as a dispersed phase into the polypropylene matrix. [0004] However, in Doshev, P. et al., Fracture charac...

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Problems solved by technology

[0004] However, in Doshev, P. et al., Fracture characteristics and deformation behavior of heterophasic ethylene-propylenecopolymer as function of the dispersed phase composition (multiphase ethylene-propylene copolymer as the fracture characteristics and deformation behavior of the dispersed phase component function), Polymer( Polymer), 46(2005), 9411-9422, and Grein, C et al., Impact Modified Isotactic Polypropylene with Controlled Rubber Intrinsic Viscosities: Some New Aspects about Morphology and Fracture (impact modified isotactic polymer with controlled rubber intrinsic viscosity Stereopolypropylene: some new properties in morphology and fracture), J Appl Polymer Sci (Journal of Applied Polymer Chemistry), 87 (2003), 1702-1712, the authors of these documents have found that when using the traditional For four types of Ziegler-Natta catalysts, the increase of ethylene content in the dispersed phase of ethylene-propylene copolymer leads to an increase of interfacial tension

Consequently, the size of the ethylene-propylene copolymer particles increases, thereby negatively affecting the brittle-ductile transition and Charpy impact strength

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