Polypropylene compositions suitable for automotive applications

Abstract

A heterophasic polypropylene composition (PC) comprising: A) from 40.0 to 80.0 wt.-%, of a ZN-HECO having an MFR2, of 1.0 to 8.0 g / 10 min, a CRYSTEX QC soluble fraction, of 20.0 to 50.0 wt.-%, a C2(SF), of 20.0 to 60.0 wt.-%, and a C2 content of 8 to 30 wt.-%, and B) from 20.0 to 60.0 wt.-%, of a SSC-homopolypropylene having an MFR2 of 20 to 3000 g / 10 min, wherein the PC has an MFR2 of 5.0 to 100 g / 10 min and a VOC content of 0 to 50 µg / g.

Description

[0001] Polypropylene compositions suitable for automotive applications Field of the Invention The present invention relates to a heterophasic polypropylene composition comprising a heterophasic propylene-ethylene copolymer and a propylene homopolymer, as well as to articles comprising said heterophasic polypropylene composition. Background to the Invention Automotive interior parts like dashboards, door claddings, trims etc. are commonly made from polymers; especially propylene based resins are widely used for these applications. It is often tried to maintain the high-quality perception till the end of the car's lifetime and therefore the polymer should provide high resistance to scratches e.g. from keys, fingernails, rings etc. In comparison to metals polymers have rather low stiffness and low surface hardness and thus are much more prone to scratches. In order to achieve a good scratch resistance of the end product quite often auxiliary substances, such as for example HDPE and / or slip agents are added to the polymer. Moreover for automotive interior parts in the recent years a stronger focus has been set on reducing emissions and odour and improving organoleptic properties of the polymer compositions. Especially low emissions as well as low amounts of volatile organic compounds and fogging are key issues in such applications. In the field of plastics, the term "emission" means the release of volatile organic compounds due to the thermal decomposition and oxidation of the polymer. It is commonly known from literature (e.g. Hopfer H., Anal. Bioanal. Chem., 2012, 402(2), 903-19) that emissions and odours are mainly originating from primary polymerization products, degradation products and additives. Although the phenomenon is increased in the case of high temperatures e.g. during the extrusion or compounding step of the polymer composition, emissions and odours also occur in the automotive interior end products at normal atmospheric temperatures. Some of the emitted volatile substances can form milky precipitates on the windscreen which of course have a negative influence on the visibility and thereby effect the safety of driver and passengers. Furthermore, the odour of those substances is normally rather unpleasant, if not hazardous for health. From a chemical point of view, emissions are light, short-chain alkanes to oligomers. Volatile organic compounds (VOC) are defined as emissions of very light to light alkanes with a chain length of ≤C25, whereas the FOG value is defined as emissions of additives, alkanes and oligomers with a chain length of C14 to C32. The bad odour of such polymer compositions is primarily caused by aldehydes and ketones as oxidation products. Propylene contains approximately 15 to 30 odourous substances such as e.g. (E)-2-heptanal, heptanal, octanal or decanal. Extensive work has been undertaken to reduce the presence of volatile odourous compounds in compositions for automotive applications; however, the main method of reducing the content of such compounds is to aerate the composition thereby manually removing said volatile compounds. Although effective, this process is energy intensive and other strategies would allow for energy savings (i.e. reduction in the emittance of CO2). Whilst some polymers naturally contain lower amounts of volatile and / or semi-volatile organic compounds, it has been difficult to obtain compositions that achieve a reduced odour without sacrificing the mechanical properties of the composition (in particular the balance of stiffness with impact strength). As such, there is still a pressing need to develop polypropylene compositions having reduced content of volatile and semi-volatile organic compounds without the need for energy- intensive aeration processes and without sacrificing other beneficial properties of the composition, such as mechanical properties. Summary of the Invention It is the finding of the present invention that the combination of high flow metallocene- catalyzed propylene homopolymers with Ziegler-Natta catalyzed heterophasic propylene- ethylene copolymers allows for the provision of heterophasic polypropylene compositions having an impressive balance of mechanical properties and low odour, without the need for an energy intensive aeration step. Therefore, in a first aspect, the present invention is directed to a heterophasic polypropylene composition (PC) comprising: A) from 40.0 to 80.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a heterophasic propylene-ethylene copolymer (HECO), having a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 1.0 to 8.0 g / 10 min, comprising: i) a crystalline matrix (M) being a propylene homo- or copolymer that is free from 2,1-regiodefects, as determined by quantitative13C-NMR spectroscopic analysis; and ii) an amorphous propylene-ethylene elastomer (E), wherein the polymeric part of the heterophasic propylene-ethylene copolymer (HECO) has the following properties: a) a soluble fraction (SF) content, determined by CRYSTEX QC analysis, in the range from 20.0 to 50.0 wt.-%, based on the total weight of the heterophasic propylene ethylene copolymer (HECO), and a crystalline fraction (CF) content, determined by CRYSTEX QC analysis, in the range from 50.0 to 80.0 wt.-%, based on the total weight of the heterophasic propylene ethylene copolymer (HECO); b) an ethylene content of the CRYSTEX QC soluble fraction (C2(SF)), determined according to CRYSTEX QC analysis, in the range from 20.0 to 60.0 wt.-%; and c) a total ethylene content (C2), determined according to CRYSTEX QC analysis, in the range from 8 to 30 wt.-%, and B) from 20.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a propylene homopolymer (h-PP) having the following properties: i) a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 20 to 3000 g / 10 min; ii) a content of 2,1-regiodefects, as determined by quantitative13C-NMR spectroscopic analysis, in the range from 0.05 to 1.20 mol-%, wherein the sum of the individual amounts of the heterophasic propylene-ethylene copolymer (HECO) and the propylene homopolymer (h-PP) is in the range from 90.0 to 100.0 wt.-%, relative to the total polymer content of the heterophasic polypropylene composition (PC), and wherein the heterophasic polypropylene composition (PC) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 5.0 to 100 g / 10 min and a content of volatile organic compounds (VOC), determined according to VDA 278 October 2011, in the range from 0 to 50 µg / g. In a second aspect, the present invention is directed to an article, more preferably an automotive article, comprising at least 90 wt.-%, more preferably at least 95 wt.-%, most preferably at least 98 wt.-% of the heterophasic polypropylene composition (PC) of the first aspect. Definitions Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although, any methods and materials similar or equivalent to those described herein can be used in practice for testing of the present invention, the preferred materials and methods are described herein. In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below. Unless clearly indicated otherwise, use of the terms “a,” “an,” and the like refers to one or more. In the following, amounts are given in % by weight (wt.-%) unless it is stated otherwise. A propylene homopolymer is a polymer that essentially consists of propylene monomer units. Due to impurities especially during commercial polymerization processes, a propylene homopolymer can comprise up to 0.1 mol-% comonomer units, preferably up to 0.05 mol-% comonomer units and most preferably up to 0.01 mol-% comonomer units. A propylene copolymer is a copolymer of propylene monomer units and comonomer units, preferably selected from ethylene and C4-C8alpha-olefins. A propylene random copolymer is a propylene copolymer wherein the comonomer units are randomly distributed along the polymer chain, whilst a propylene block copolymer comprises blocks of propylene monomer units and blocks of comonomer units. Propylene random copolymers can comprise comonomer units from one or more comonomers different in their amounts of carbon atoms. Heterophasic propylene copolymers typically comprise: a) a crystalline propylene homopolymer or copolymer matrix (M); and b) an elastomeric rubber, preferably a propylene-ethylene elastomer (E); In case of a random-heterophasic propylene copolymer, said crystalline matrix phase is a random copolymer of propylene and at least one alpha-olefin comonomer. The elastomeric phase can be a propylene copolymer with a high amount of comonomer that is not randomly distributed in the polymer chain but is distributed in a comonomer-rich block structure and a propylene-rich block structure. A heterophasic polypropylene usually differentiates from a one-phasic propylene copolymer in that it shows two distinct glass transition temperatures Tg which are attributed to the matrix phase and the elastomeric phase. The present invention will now be described in more detail. Detailed Description Heterophasic polypropylene composition (PC) In a first aspect, the present invention is directed to a heterophasic polypropylene composition (PC) comprising: A) from 40.0 to 80.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a heterophasic propylene-ethylene copolymer (HECO); and B) from 20.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a propylene homopolymer (h-PP). The sum of the individual amounts of the heterophasic propylene-ethylene copolymer (HECO) and the propylene homopolymer (h-PP) is in the range from 90.0 to 100.0 wt.-%, relative to the total polymer content of the heterophasic polypropylene composition (PC). The heterophasic polypropylene composition (PC) preferably comprises: A) from 45.0 to 70.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a heterophasic propylene-ethylene copolymer (HECO); and B) from 30.0 to 55.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a propylene homopolymer (h-PP). The heterophasic polypropylene composition (PC) more preferably comprises: A) from 50.0 to 65.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a heterophasic propylene-ethylene copolymer (HECO); and B) from 35.0 to 50.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a propylene homopolymer (h-PP). The heterophasic polypropylene composition (PC) most preferably comprises: A) from 50.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a heterophasic propylene-ethylene copolymer (HECO); and B) from 40.0 to 50.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a propylene homopolymer (h-PP). Furthermore, the heterophasic polypropylene composition (PC) comprises, more preferably consists of: A) from 40.0 to 80.0 wt.-%, more preferably from 45.0 to 70.0 wt.-%, yet more preferably from 50.0 to 65.0 wt.-%, most preferably from 50.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the heterophasic propylene-ethylene copolymer (HECO); B) from 20.0 to 60.0 wt.-%, more preferably from 30.0 to 55.0 wt.-%, yet more preferably from 35.0 to 50.0 wt.-%, most preferably from 40.0 to 50.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the propylene homopolymer (h-PP); C) from 0.0 to 40.0 wt.-%, more preferably from 0.0 to 25.0 wt.-%, yet more preferably from 0.0 to 15.0 wt.-%, most preferably from 0.0 to 10.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more inorganic fillers (F); D) from 0.0 to 1.0 wt.-%, more preferably from 0.0 to 0.5 wt.-%, yet more preferably from 0.0 to 0.3 wt.-%, most preferably from 0.0 to 0.2 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more nucleating agents (NU); and E) from 0.0 to 5.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more further additives different from the one or more inorganic fillers (F) and the one or more nucleating agents (NU). In one embodiment, the heterophasic polypropylene composition (PC) comprises, more preferably consists of: A) from 40.0 to 80.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the heterophasic propylene-ethylene copolymer (HECO); B) from 20.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the propylene homopolymer (h-PP); C) from 0.0 to 40.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more inorganic fillers (F); D) from 0.0 to 1.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more nucleating agents (NU); and E) from 0.0 to 5.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more further additives different from the one or more inorganic fillers (F) and the one or more nucleating agents (NU). In a further embodiment, the heterophasic polypropylene composition (PC) comprises, more preferably consists of: A) from 45.0 to 70.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the heterophasic propylene-ethylene copolymer (HECO); B) from 30.0 to 55.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the propylene homopolymer (h-PP); C) from 0.0 to 25.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more inorganic fillers (F); D) from 0.0 to 0.5 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more nucleating agents (NU); and E) from 0.0 to 5.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more further additives different from the one or more inorganic fillers (F) and the one or more nucleating agents (NU). In yet a further embodiment, the heterophasic polypropylene composition (PC) comprises, more preferably consists of: A) from 50.0 to 65.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the heterophasic propylene-ethylene copolymer (HECO); B) from 35.0 to 50.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the propylene homopolymer (h-PP); C) from 0.0 to 15.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more inorganic fillers (F); D) from 0.0 to 0.3 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more nucleating agents (NU); and E) from 0.0 to 5.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more further additives different from the one or more inorganic fillers (F) and the one or more nucleating agents (NU). In a particularly preferred embodiment, the heterophasic polypropylene composition (PC) comprises, more preferably consists of: A) from 50.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the heterophasic propylene-ethylene copolymer (HECO); B) from 40.0 to 50.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the propylene homopolymer (h-PP); C) from 0.0 to 10.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more inorganic fillers (F); D) from 0.0 to 0.2 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more nucleating agents (NU); and E) from 0.0 to 5.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more further additives different from the one or more inorganic fillers (F) and the one or more nucleating agents (NU). The heterophasic polypropylene composition (PC) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 5.0 to 100 g / 10 min, more preferably in the range from 8 to 70 g / 10 min, most preferably in the range from 10 to 50 g / 10 min. The heterophasic polypropylene composition (PC) preferably has a xylene cold soluble content, determined according to ISO 16152, in the range from 10.0 to 30.0 wt.-%, more preferably in the range from 15 to 25 wt.-%, most preferably in the range from 20 to 23 wt.- %. The heterophasic polypropylene composition (PC) has a content of volatile organic compounds (VOC), determined according to VDA 278 October 2011, in the range from 0 to 50 µg / g, more preferably in the range from 0 to 40 µg / g, most preferably in the range from 0 to 30 µg / g. The heterophasic polypropylene composition (PC) preferably has a content of semi-volatile organic compounds (FOG), determined according to VDA 278 October 2011, in the range from 0 to 200 µg / g, more preferably in the range from 0 to 150 µg / g, most preferably in the range from 0 to 120 µg / g. The heterophasic polypropylene composition (PC) preferably has a flexural modulus, determined according to ISO 178 on 80×10×4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 800 to 2000 MPa, more preferably in the range from 850 to 1500 MPa, most preferably in the range from 900 to 1200 MPa The heterophasic polypropylene composition (PC) preferably has a Charpy Notched Impact Strength (NIS(+23°C)) measured according to ISO 179-1 eA at 23 °C on 80×10×4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 4.0 to 20 kJ / m2, more preferably in the range from 5.0 to 15 kJ / m2, most preferably in the range from 6 to 10 kJ / m2. The heterophasic polypropylene composition (PC) preferably has a low temperature Charpy Notched Impact Strength (NIS(-20°C)) measured according to ISO 179-1 eA at -20 °C on 80×10×4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 3.0 to 15 kJ / m2, more preferably in the range from 4.0 to 10 kJ / m2, most preferably in the range from 4.3 to 8.0 kJ / m2. The individual components will now be described in more detail. Heterophasic propylene-ethylene copolymer (HECO) One essential component of the heterophasic polypropylene composition (PC) is the heterophasic propylene-ethylene copolymer (HECO). The heterophasic propylene-ethylene copolymer (HECO) is present in the heterophasic polypropylene composition (PC) in an amount in the range from 40.0 to 80.0 wt.-%, more preferably in the range from 45.0 to 70.0 wt.-%, yet more preferably in the range from 50.0 to 65.0 wt.-%, most preferably in the range from 50.0 to 60.0 wt.-%. The heterophasic propylene-ethylene copolymer (HECO) comprises: a) a crystalline matrix (M) being a propylene homo- or copolymer; and b) an amorphous propylene-ethylene elastomer (E). Preferably, the crystalline matrix (M) is a propylene homopolymer. Preferably, the crystalline matrix (M) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 1.0 to 10.0 g / 10 min, more preferably in the range from 1.5 to 8.0 g / 10 min, most preferably in the range from 2.0 to 6.0 g / 10 min. The crystalline matrix (M) of the heterophasic propylene-ethylene copolymer (HECO) is free from 2,1-regiodefects, as determined by13C-NMR spectroscopy. Being free of 2,1-regiodefects is an indication that the heterophasic propylene-ethylene copolymer (HECO) has been polymerized in the presence of a Ziegler-Natta catalyst. Therefore, it is further preferred that the heterophasic propylene-ethylene copolymer (HECO) has been polymerized in the presence of a Ziegler-Natta catalyst. The heterophasic propylene-ethylene copolymer (HECO) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 1.0 to 8.0 g / 10 min, more preferably in the range from 1.5 to 6.0 g / 10 min, most preferably in the range from 2.0 to 4.0 g / 10 min. The heterophasic propylene-ethylene copolymer (HECO) preferably has a first melting temperature (Tm1), determined by differential scanning calorimetry (DSC), in the range from 160 to 170 °C, more preferably in the range from 162 to 168 °C, most preferably in the range from 163 to 167 °C. The heterophasic propylene-ethylene copolymer (HECO) preferably has an enthalpy of fusion (Hm1) associated with the first melting temperature, determined by differential scanning calorimetry (DSC), in the range from 50 to 80 J / g, more preferably in the range from 55 to 75 J / g, most preferably in the range from 60 to 70 J / g. The heterophasic propylene-ethylene copolymer (HECO) preferably has a crystallization temperature (Tc), determined by differential scanning calorimetry (DSC), in the range from 115 to 130 °C, more preferably in the range from 117 to 127 °C, most preferably in the range from 120 to 125 °C. The heterophasic propylene-ethylene copolymer (HECO) preferably has a first glass transition temperature (Tg1), determined according to ISO 6721-7, in the range from -65 to - 40 °C, more preferably in the range from -55 to -41 °C, most preferably in the range from - 50 to -42 °C. The heterophasic propylene-ethylene copolymer (HECO) preferably has a second glass transition temperature (Tg2), determined according to ISO 6721-7, in the range from -5 to +5 °C, more preferably in the range from -3 to +3 °C, most preferably in the range from -1 to +1 °C. The polymeric part of the heterophasic propylene-ethylene copolymer (HECO) may be characterized according to the CRYSTEX QC method using trichlorobenzene (TCB) as a solvent. This method is described below in the determination methods section. The crystalline fraction (CF) contains for the most part the matrix phase and only a small part of the elastomeric phase and the soluble fraction (SF) contains for the most part the elastomeric phase and only a small part of the matrix phase. In some cases, this method results in more useful data, since the crystalline fraction (CF) and the soluble fraction (SF) more accurately correspond to the matrix and elastomeric phases respectively. Due to the differences in the separation methods of xylene extraction and CRYSTEX QC method the properties of XCS / XCI fractions on the one hand and crystalline / soluble (CF / SF) fractions on the other hand are not exactly the same, meaning that the amounts of matrix phase and elastomeric phase can differ as well as the properties. The heterophasic propylene-ethylene copolymer (HECO) has a soluble fraction (SF) content, determined according to CRYSTEX QC analysis, in the range from 20 to 50 wt.-%, more preferably in the range from 30 to 45 wt.-%, most preferably in the range from 35 to 43 wt.- %. The heterophasic propylene-ethylene copolymer (HECO) has an ethylene content of the soluble fraction (C2(SF)), determined by CRYSTEX QC analysis, in the range from 20.0 to 60.0 wt.-%, more preferably in the range from 25.0 to 50.0 wt.-%, most preferably in the range from 30.0 to 40.0 wt.-%. The heterophasic propylene-ethylene copolymer (HECO) preferably has an intrinsic viscosity of the soluble fraction (iV(SF)), determined by CRYSTEX QC analysis, in the range from 1.50 to 5.00 dL / g, more preferably in the range from 1.80 to 3.00 dL / g, most preferably in the range from 2.00 to 2.50 dL / g. The heterophasic propylene-ethylene copolymer (HECO) has a crystalline fraction (CF) content, determined by CRYSTEX QC analysis, in the range from 50 to 80 wt.-%, more preferably in the range from 55 to 70 wt.-%, most preferably in the range from 57 to 65 wt.- %. The heterophasic propylene-ethylene copolymer (HECO) preferably has an ethylene content of the crystalline fraction (C2(CF)), determined by CRYSTEX QC analysis, in the range from 0.0 to 10.0 wt.-%, more preferably in the range from 3.0 to 9.0 wt.-%, most preferably in the range from 5.0 to 8.0 wt.-%. The heterophasic propylene-ethylene copolymer (HECO) preferably has an intrinsic viscosity of the crystalline fraction (iV(CF)), determined by CRYSTEX QC analysis, in the range from 1.50 to 3.00 dL / g, more preferably in the range from 2.00 to 2.80 dL / g, most preferably in the range from 2.20 to 2.70 dL / g. The heterophasic propylene-ethylene copolymer (HECO) preferably has an intrinsic viscosity (iV(total)), determined by CRYSTEX QC analysis, in the range from 1.50 to 3.00 dL / g, more preferably in the range from 2.00 to 2.80 dL / g, most preferably in the range from 2.20 to 2.70 dL / g. The heterophasic propylene-ethylene copolymer (HECO) preferably has an ethylene content (C2(total)), determined by CRYSTEX QC analysis, in the range from 8.0 to 30.0 wt.-%, more preferably in the range from 10.0 to 25.0 wt.-%, most preferably in the range from 15.0 to 20.0 wt.-%. It is especially preferred that the crystalline matrix (M) of the heterophasic propylene- ethylene copolymer (HECO) is a homopolymer and is bimodal with respect to molecular weight, more preferably comprises: i) from 30 to 70 wt.-%, more preferably form 40 to 60 wt.-%, most preferably from 45 to 55 wt.-%, relative to the total weight of the crystalline matrix (M), of a first propylene homopolymer fraction (PP1); and ii) from 30 to 70 wt.-%, more preferably form 40 to 60 wt.-%, most preferably from 45 to 55 wt.-%, relative to the total weight of the crystalline matrix (M), of a second propylene homopolymer fraction (PP2). The first propylene homopolymer fraction (PP1) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 4.5 to 15.0 g / 10 min, more preferably in the range from 6.0 to 13.0 g / 10 min, most preferably in the range from 7.5 to 11.0 g / 10 min. The second propylene homopolymer fraction (PP2) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 0.1 to 4.0 g / 10 min, more preferably in the range from 0.3 to 2.5 g / 10 min, most preferably in the range from 0.5 to 1.5 g / 10 min. It is furthermore preferred that the heterophasic propylene-ethylene copolymer (HECO) is not visbroken. The process of visbreaking involves the addition of a visbreaking agent, typically a peroxide- type radical initiator, to a polymer composition, typically during the compounding step. This visbreaking agent promotes radical processes that may result in beta-scission of the polymer chain. Although combination of polymer chains (i.e. crosslinking) is also possible, the predominant effect is that of visbreaking, wherein the longest polymer chains present are significantly shortened. The effect of visbreaking on the properties is generally observed as an increased MFR, as a result of the degradation of the especially long chains responsible for the viscosity. The person skilled in the art would know that polymer compositions that have been visbroken have a characteristic molecular weight distribution curve, with an unusually low amount of polymer in the so-called “high molecular weight tail” of the curve. Furthermore, decomposition products of the visbreaking agent can be detected, enabling the person skilled in the art to deduce that the polymer composition has been visbroken. In the present case, the heterophasic propylene-ethylene copolymer preferably is free from peroxide degradation products, more preferably free from all degradation products of visbreaking agents. Propylene homopolymer (h-PP) The other essential component of the heterophasic polypropylene composition (PC) is the propylene homopolymer (h-PP). The propylene homopolymer is present in the heterophasic polypropylene composition (PC) in an amount in the range from 20.0 to 60.0 wt.-%, more preferably in the range from 30.0 to 55.0 wt.-%, yet more preferably in the range from 35.0 to 50.0 wt.-%, most preferably in the range from 40.0 to 50.0 wt.-%. The propylene homopolymer has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 20 to 3000 g / 10 min, more preferably in the range from 50 to 2500 g / 10 min, most preferably in the range from 75 to 2000 g / 10 min. The propylene homopolymer preferably has a melting temperature (Tm), determined by differential scanning calorimetry (DSC), in the range from 145 to 160 °C, more preferably in the range from 150 to 159 °C, most preferably in the range from 152 to 158 °C. The propylene homopolymer preferably has a xylene cold soluble content, determined according to ISO 16152, in the range from 0.0 to 1.0 wt.-%, more preferably in the range from 0.0 to 0.7 wt.-%, most preferably in the range from 0.0 to 0.4 wt.-%. The propylene homopolymer has a content of 2,1-regiodefects, as determined by quantitative13C-NMR spectroscopic analysis, in the range from 0.05 to 1.20 mol-%, more preferably in the range from 0.20 to 1.00 mol-%, most preferably in the range from 0.30 to 0.80 mol-%. The presence of 2,1-regiodefects is an indication that the propylene homopolymer (h-PP) has been polymerized in the presence of a single site catalyst. Therefore, it is further preferred that the propylene homopolymer (h-PP) has been polymerized in the presence of a single site catalyst, more preferably in the presence of a metallocene catalyst. It is preferred that the single site catalyst comprises a metallocene complex, a co-catalyst system comprising a boron-containing co-catalyst and / or aluminoxane co-catalyst, and a silica support. In particular, it is preferred that the single site catalyst comprises: (i) a metallocene complex of the general formula (I)

[0002] R4is a C(R9)3group, with R9being a linear or branched C1-C6-alkyl group, R5is hydrogen or an aliphatic C1-C20-hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table; R6is hydrogen or an aliphatic C1-C20-hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table; or R5and R6can be taken together to form a 5 membered saturated carbon ring which is optionally substituted by n groups R10, n being from 0 to 4; each R10is same or different and may be a C1-C20-hydrocarbyl group, or a C1-C20- hydrocarbyl group optionally containing one or more heteroatoms belonging to groups 14-16 of the periodic table; R7is H or a linear or branched C1-C6-alkyl group or an aryl or heteroaryl group having 6 to 20 carbon atoms optionally substituted by one to three groups R11, each R11are independently the same or can be different and are hydrogen, a linear or branched C1-C6-alkyl group, a C7-20-arylalkyl, C7-20-alkylaryl group or C6-20-aryl group or an OY group, wherein Y is a C1-10-hydrocarbyl group, (ii) a co-catalyst system comprising a boron containing co-catalyst and / or an aluminoxane co-catalyst, and (iii) a silica support. The term “sigma-donor ligand” is well understood by the person skilled in the art, i.e. a group bound to the metal via a sigma bond. Thus the anionic ligands “X” can independently be halogen or be selected from the group consisting of R’, OR’, SiR’3, OSiR’3, OSO2CF3, OCOR’, SR’, NR’2 or PR’2 group wherein R´ is independently hydrogen, a linear or branched, cyclic or acyclic, C1 to C20 alkyl, C2 to C20 alkenyl, C2 to C20 alkynyl, C3 to C12 cycloalkyl, C6 to C20 aryl, C7 to C20 arylalkyl, C7 to C20 alkylaryl, C8 to C20 arylalkenyl, in which the R’ group can optionally contain one or more heteroatoms belonging to groups 14 to 16. In a preferred embodiment the anionic ligands “X” are identical and either halogen, like Cl, or methyl or benzyl. A preferred monovalent anionic ligand is halogen, in particular chlorine (Cl). Preferred complexes of the metallocene catalyst include: rac-dimethylsilanediylbis[2-methyl-4-(3’,5’-dimethylphenyl)-5-methoxy-6-tert-butylinden- 1- yl] zirconium dichloride, rac-anti-dimethylsilanediyl[2-methyl-4-(4´-tert-butylphenyl)-inden-1-yl][2-methyl-4-(4´- tertbutylphenyl)- 5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl[2-methyl-4-(4´-tert-butylphenyl)-inden-1-yl][2-methyl-4-phenyl- 5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl[2-methyl-4-(3´,5´-tert-butylphenyl)-1,5,6,7-tetrahydro-sindacen- 1-yl][2-methyl-4-(3’,5’-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl[2-methyl-4,8-bis-(4´-tert-butylphenyl)-1,5,6,7-tetrahydro- sindacen-1-yl][2-methyl-4-(3’,5’-dimethyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl[2-methyl-4,8-bis-(3’,5’-dimethylphenyl)-1,5,6,7-tetrahydro-s- indacen-1-yl] [2-methyl-4-(3’,5’-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride, rac-anti-dimethylsilanediyl[2-methyl-4,8-bis-(3’,5’-dimethylphenyl)-1,5,6,7-tetrahydro-s- indacen-1-yl][2-methyl-4-(3’,5’-5 ditert-butyl-phenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride. Especially preferred is rac-anti-dimethylsilanediyl[2-methyl-4,8-bis-(3’,5’-dimethylphenyl)- 1,5,6,7-tetrahydro-s indacen-1-yl] [2-methyl-4-(3’,5’-dimethylphenyl)-5-methoxy-6-tert- butylinden-1-yl] zirconium dichloride. The ligands required to form the complexes and hence catalysts for preparing the propylene homopolymer (h-PP) can be synthesized by any process and the skilled organic chemist would be able to devise various synthetic protocols for the manufacture of the necessary ligand materials. For Example WO2007 / 116034 discloses the necessary chemistry. Synthetic protocols can also generally be found in WO 2002 / 02576, WO 2011 / 135004, WO 2012 / 084961, WO 2012 / 001052, WO 2011 / 076780, WO 2015 / 158790 and WO 2018 / 122134. Especially reference is made to WO 2019 / 179959, in which the most preferred catalyst for preparing the propylene homopolymer (h-PP) of the present invention is described. To form an active catalytic species it is normally necessary to employ a cocatalyst as is well known in the art. It is thus preferred that the co-catalyst system comprises a boron containing co-catalyst and / or an aluminoxane co-catalyst in combination with the above defined metallocene catalyst complex. The aluminoxane co-catalyst can be one of formula (II): where n is usually from 6 to 20 and R has the meaning below. Aluminoxanes are formed on partial hydrolysis of organoaluminum compounds, for example those of the formula AlR3, AlR2Y and Al2R3Y3 where R can be, for example, C1-C10 alkyl, preferably C1-C5 alkyl, or C3-C10 cycloalkyl, C7-C12 arylalkyl or alkylaryl and / or phenyl or naphthyl, and where Y can be hydrogen, halogen, preferably chlorine or bromine, or C1-C10 alkoxy, preferably methoxy or ethoxy. The resulting oxygen-containing aluminoxanes are not in general pure compounds but mixtures of oligomers of the formula (II). The preferred aluminoxane is methylaluminoxane (MAO). Since the aluminoxanes used as co-catalysts for preparing the propylene homopolymer (h-PP) are not, owing to their mode of preparation, pure compounds, the molarity of aluminoxane solutions hereinafter is based on their aluminium content. A boron containing co-catalyst can be used instead of the aluminoxane co-catalyst or the aluminoxane co-catalyst can be used in combination with a boron containing co-catalyst. It will be appreciated by the person skilled in the art that where boron based co-catalysts are employed, it is normal to pre-alkylate the complex by reaction thereof with an aluminium alkyl compound, such as TIBA. This procedure is well known and any suitable aluminium alkyl, e.g. Al(C1-C6alkyl)3can be used. Preferred aluminium alkyl compounds are triethylaluminium, tri-isobutylaluminium, tri-isohexylaluminium, tri-n-octylaluminium and tri-isooctylaluminium. Alternatively, when a borate co-catalyst is used, the metallocene catalyst complex is in its alkylated version, that is for example a dimethyl or dibenzyl metallocene catalyst complex can be used. Boron based co-catalysts of interest include those of formula (III) BY3 (III) wherein Y is the same or different and is a hydrogen atom, an alkyl group of from 1 to about 20 carbon atoms, an aryl group of from 6 to about 15 carbon atoms, alkylaryl, arylalkyl, haloalkyl or haloaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6- 20 carbon atoms in the aryl radical or fluorine, chlorine, bromine or iodine. Preferred options are trifluoroborane, triphenylborane, tris(4-fluorophenyl)borane, tris(3,5- difluorophenyl)borane, tris(4-fluoromethylphenyl)borane, tris(2,4,6-trifluorophenyl)borane, tris(penta-fluorophenyl)borane, tris(tolyl)borane, tris(3,5-dimethyl-phenyl)borane, tris(3,5- difluorophenyl)borane and / or tris (3,4,5-trifluorophenyl)borane. Particular preference is given to tris(pentafluorophenyl)borane. However it is preferred that borates are used, i.e. compounds containing a borate 3+ ion. Such ionic co-catalysts preferably contain a non-coordinating anion such as tetrakis(pentafluorophenyl)borate and tetraphenylborate. Suitable counterions are protonated amine or aniline derivatives such as methylammonium, anilinium, dimethylammonium, diethylammonium, N- methylanilinium, diphenylammonium, N,N-dimethylanilinium, trimethylammonium, triethylammonium, tri-n-butylammonium, methyldiphenylammonium, pyridinium, p-bromo-N,N- dimethylanilinium or p-nitro-N,N-dimethylanilinium. It has been surprisingly found that certain boron co-catalysts are especially preferred. Preferred borates of use for preparing the propylene homopolymer (h-PP) therefore comprise the trityl ion. Thus the use of N,N-dimethylammonium-tetrakispentafluorophenylborate and Ph3CB(PhF5)4and analogues therefore are especially favoured. The preferred co-catalysts are aluminoxanes, more preferably methylaluminoxanes, combinations of aluminoxanes with Al-alkyls, boron or borate co-catalysts, and combination of aluminoxanes with boron-based co-catalysts. The catalyst system for preparing the propylene homopolymer (h-PP) is preferably used in supported form. The particulate support material used is silica or a mixed oxide such as silica-alumina, in particular silica. The use of a silica support is preferred. The skilled practitioner is aware of the procedures required to support a metallocene catalyst. In a preferred embodiment, the catalyst system corresponds to the ICS4 of WO 2020 / 239598 A1. One or more inorganic fillers (F) An optional component of the heterophasic polypropylene composition is one or more inorganic fillers (F). In the broadest sense, these fillers may be any inorganic fillers known to the person skilled in the art; however, it is preferred that the one or more inorganic fillers (F) are selected from the group consisting of talc, mica, kaolin, wollastonite, glass fiber, and calcium carbonate, more preferably from the group consisting of talc, calcium carbonate, and glass fibers. Most preferably, at least one of the one or more inorganic fillers is talc. It is preferred that the total content of the one or more inorganic fillers (F)is in the range from 0.0 to 40.0 wt.-%, more preferably in the range from 0.0 to 25.0 wt.-%, yet more preferably in the range from 0.0 to 15.0 wt.-%, most preferably in the range from 0.0 to 10.0 wt.-%. One or more nucleating agents (NU) An optional component of the heterophasic polypropylene composition is one or more nucleating agents (NU). In the broadest sense, the one or more nucleating agents may be any nucleating agent known to the person skilled in the art. It is preferred that the one or more nucleating agents (NU) are one or more alpha nucleating agents. The one or more nucleating agents may be polymeric nucleating agents, such as polyvinylcyclohexane, or non-polymeric nucleating agents, such as sorbitol derivatives, benzoates or organophosphates, or a mixture of polymeric and non-polymeric nucleating agents. It is preferred that the total content of the one or more nucleating agents (NU) is in the range from 0.0 to 1.0 wt.-%, more preferably in the range from 0.0 to 0.5 wt.-%, yet more preferably in the range from 0.0 to 0.3 wt.-%, most preferably in the range from 0.0 to 0.2 wt.-%. One or more additives An optional component of the heterophasic polypropylene composition is one or more further additives different from the one or more inorganic fillers (F) and the one or more nucleating agents (NU). The one or more further additives, if present, are provided in an amount in the range from 0.0 to 5.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC). The skilled practitioner would be able to select suitable additives that are well known in the art. The additives are preferably selected from pigments, antioxidants, UV-stabilisers, anti- scratch agents, mould release agents, acid scavengers, lubricants, anti-static agents, and mixtures thereof. It is understood that the content of additives includes any carrier polymers used to introduce the additives to the polypropylene composition (PC), i.e. masterbatch carrier polymers. An example of such a carrier polymer would be a polypropylene homopolymer in the form of powder. Article In a second aspect, the present invention is directed to an article comprising the heterophasic polypropylene composition (PC) of the first aspect. The article comprises at least 90 wt.-%, more preferably at least 95 wt.-%, most preferably at least 98 wt.-% of the heterophasic polypropylene composition (PC). The article is preferably an automotive article, more preferably an automotive interior article, most preferably selected from the group consisting of instrument panel, door panel, pillar trim, centre console, trunk cladding, tailgate structure, and seat cladding. The preferred embodiments and fallback positions for the heterophasic polypropylene composition (PC) of the first aspect apply mutatis mutandis to the articles of the second aspect.

[0003] E X A M P L E S 1. Determination methods The following definitions of terms and determination methods apply for the above general description of the invention including the claims as well as to the below examples unless otherwise defined. Quantification of microstructure by NMR spectroscopy Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the comonomer and regiodefect content of the polymers. Quantitative13C{1H} NMR spectra were recorded in the solution-state using a Bruker Avance III 400 NMR spectrometer operating at 400.15 and 100.62 MHz for1H and13C respectively. All spectra were recorded using a13C optimised 10 mm extended temperature probehead at 125°C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in approximately 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) along with chromium-(III)-acetylacetonate (Cr(acac)3) resulting in a 65 mM solution of relaxation agent in solvent {singh09}. To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatary oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme {zhou07,busico07}. A total of 6144 (6k) transients were acquired per spectra. Quantitative13C{1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Characteristic signals corresponding to the incorporation of ethylene were observed {wang00, cheng84, randall89}. The comonomer fraction was quantified using the method of Wang et. al. {wang00} through integration of multiple signals across the whole spectral region in the13C{1H} spectra. This method was chosen for its robust nature and ability to account for the presence of regiodefects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents. For systems where only isolated ethylene in PPEPP sequences was observed the method of Wang et. al. was modified to reduce the influence of non-zero integrals of sites that are known to be not present. This approach reduced the overestimation of ethylene content for such systems and was achieved by reduction of the number of sites used to determine the absolute ethylene content. Through the use of this set of sites the corresponding integral equation becomes pS = IA + (0.5 * IB) pT = ID + IF + ID p = (pS + pT) / 2 e = 0.5 * (IH + (0.5 * IB)) fE = e / (e + p) using the same notation used in the article of Wang et. al. {wang00}. The mole percent comonomer incorporation was calculated from the mole fraction: E [mol-%] = 100 * fE The weight percent comonomer incorporation was calculated from the mole fraction: E [wt.-%] = 100 * ( fE * 28.06 ) / ( (fE * 28.06) + ((1-fE) * 42.08) ) Characteristic signals corresponding to regiodefects were observed {resconi00, wang00}. The presence of isolated 2,1-erythro regiodefects was indicated by the presence of the two methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic sites. The presence of 2,1 regiodefect adjacent an ethylene unit was indicated by the two inequivalent Sαβ signals at 34.9 ppm and 34.7 ppm respectively and the Tγγ at 34.1 ppm. The amount of isolated 2,1-erythro regiodefects was quantified using the average integral of the two characteristic methyl sites at 17.7 (Ie8) and 17.4 (Ie6) ppm respectively: The amount of 2,1 regiodefect adjacent to ethylene (PE21) was quantified using the methine site at 34.1 ppm (ITγγ): PE21= ITγγ The total amount of propene was quantified based on the methyl region (ICH3) between 23.0 and 19.9 ppm with correction undertaken for sites included in this region not related to propene insertion. The methyl group Pγγresulting from 2,1 regiodefect adjacent to ethylene was already present in ICH3: The isolated 2,1-erythro regiodefects was multiplied by 2 to take into account the two (2) propene units in the 2, 1-erythro regiodefects. The mole percent of isolated 2,1-erythro regiodefects was quantified with respect to all propene: [21e] mol-% = 100 The mole percent of 2,1 regiodefects adjacent to ethylene was quantified with respect to all propene: [E21] mol-% = 100 The total amount of 2,1 defects was quantified as following:

[0021] mol-% = [21e] + [E21] Characteristic signals corresponding to other types of regiodefects (2,1-threo, 3,1 insertion) were not observed {resconi00}. zhou07 Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson.187 (2007) 225 busico07 Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun.2007, 28, 1128 resconi00 Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev.2000, 100, 1253 wang00 Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157 cheng84 Cheng, H. N., Macromolecules 17 (1984), 1950 singh09 Singh, G., Kothari, A., Gupta, V., Polymer Testing 285 (2009), 475 randall89 Randall, J. Macromol. Sci., Rev. Macromol. Chem. Phys.1989, C29, 201. CRYSTEX QC analysis Crystalline and soluble fractions method The crystalline (CF) and soluble fractions (SF) of the heterophasic propylene-ethylene copolymer (HECO) as well as the comonomer content and intrinsic viscosities of the respective fractions were analyzed by use of the CRYSTEX instrument, Polymer Char (Valencia, Spain). Details of the technique and the method can be found in literature (Ljiljana Jeremic, Andreas Albrecht, Martina Sandholzer & Markus Gahleitner (2020) Rapid characterization of high-impact ethylene–propylene copolymer composition by crystallization extraction separation: comparability to standard separation methods, International Journal of Polymer Analysis and Characterization, 25:8, 581-596) The crystalline and amorphous fractions were separated through temperature cycles of dissolution at 160 °C, crystallization at 40 °C and re-dissolution in 1,2,4-trichlorobenzene at 160 °C. Quantification of SF and CF and determination of ethylene content (C2) were achieved by means of an integrated infrared detector (IR4) and for the determination of the intrinsic viscosity (IV) an online 2-capillary viscometer was used. The IR4 detector was a multiple wavelength detector measuring IR absorbance at two different bands (CH3 stretching vibration (centered at app.2960 cm-1) and the CH stretching vibration (2700-3000 cm-1) that serve for the determination of the concentration and the Ethylene content in Ethylene-Propylene copolymers. The IR4 detector was calibrated with series of 8 EP copolymers with known Ethylene content in the range of 2 wt.-% to 69 wt.-% (determined by13C-NMR) and each at various concentrations, in the range of 2 and 13mg / ml. To encounter for both features, concentration and ethylene content at the same time for various polymer concentrations expected during CRYSTEX analyses the following calibration equations were applied: Conc = a + b*Abs(CH) + c*(Abs(CH))² + d*Abs(CH3) + e*(Abs(CH3)² + f*Abs(CH)*Abs(CH3) (Equation 1) CH3 / 1000C = a + b*Abs(CH) + c* Abs(CH3) + d * (Abs(CH3) / Abs(CH)) + e * (Abs(CH3) / Abs(CH))² (Equation 2) The constants a to e for equation 1 and a to f for equation 2 were determined by using least square regression analysis. The CH3 / 1000C was converted to the ethylene content in wt.-% using following relationship: Wt.-% (Ethylene in EP Copolymers) = 100 - CH3 / 1000TC * 0.3 (Equation 3) Amounts of Soluble Fraction (SF) and Crystalline Fraction (CF) were correlated through the XS calibration to the “Xylene Cold Soluble” (XCS) quantity and respectively Xylene Cold Insoluble (XCI) fractions, determined according to standard gravimetric method as per ISO16152. XS calibration was achieved by testing various EP copolymers with XS content in the range 2-31 wt.-%. The determined XS calibration was linear: Wt.-% XS = 1,01* Wt.-% SF (Equation 4) Intrinsic viscosity (IV) of the parent EP copolymer and its soluble and crystalline fractions were determined with a use of an online 2-capillary viscometer and were correlated to corresponding IV’s determined by standard method in decalin according to ISO 1628-3. Calibration was achieved with various EP PP copolymers with IV = 2-4 dL / g. The determined calibration curve was linear: IV (dL / g) = a* Vsp / c (equation 5) The samples to be analyzed were weighed out in concentrations of 10mg / ml to 20mg / ml. To avoid injecting possible gels and / or polymers which do not dissolve in TCB at 160 °C, like PET and PA, the weighed out sample was packed into a stainless steel mesh MW 0,077 / D 0,05mmm. After automated filling of the vial with 1,2,4-TCB containing 250 mg / l 2,6-tert-butyl-4- methylphenol (BHT) as antioxidant, the sample was dissolved at 160 °C until complete dissolution was achieved, usually for 60 min, with constant stirring of 400rpm. To avoid sample degradation, the polymer solution was blanketed with the N2atmosphere during dissolution. A defined volume of the sample solution was injected into the column filled with inert support where the crystallization of the sample and separation of the soluble fraction from the crystalline part was taking place. This process was repeated two times. During the first injection the whole sample as measured at high temperature, determining the IV[dl / g] and the C2[wt.-%] of the PP composition. During the second injection the soluble fraction (at low temperature) and the crystalline fraction (at high temperature) with the crystallization cycle were measured (wt.-% SF, wt.-% C2, IV). Melt Flow Rate The melt flow rate (MFR) was determined according to ISO 1133 and was indicated in g / 10 min. The MFR is an indication of the flowability, and hence the processability, of the polymer. The higher the melt flow rate, the lower the viscosity of the polymer. The MFR2 of polypropylene was determined at a temperature of 230 °C and a load of 2.16 kg. Calculation of melt flow rate MFR2 (230 °C) of the second propylene homopolymer fraction(h-PP2):^୪୭^൫ெிோ(^^)൯ି௪(^^^) × ୪୭^ (ெிோ(^^^))2= 10 ௪(^^ଶ ^^^ ^^ ^^( ^^ ^^ ) )wherein w(PP1) is the weight fraction [in wt.-%] of the first propylene homopolymer fraction (h-PP1), w(PP2) is the weight fraction [in wt.-%] of second propylene homopolymer fraction (h-PP2), MFR(PP1) is the melt flow rate MFR2 (230 °C) [in g / 10min] of the first propylene homopolymer fraction (h-PP1), MFR(PP) is the melt flow rate MFR2 (230 °C) [in g / 10min] of the crystalline matrix (M), i.e. of a blend of h-PP1 and h-PP2, MFR(PP2) is the calculated melt flow rate MFR2 (230 °C) [in g / 10min] of the second propylene homopolymer fraction (h-PP2). DSC analysis, melting temperature (Tm) and heat of fusion (Hf), crystallization temperature (Tc) and heat of crystallization (Hc): measured with a TA Instrument Q200 differential scanning calorimetry (DSC) on 5 to 7 mg samples. DSC was run according to ISO 11357 / part 3 / method C2 in a heat / cool / heat cycle with a scan rate of 10 °C / min in the temperature range of -30 to +225 °C. Crystallization temperature (Tc) and crystallization enthalpy (Hc) were determined from the cooling step, while melting temperature (Tm) and melting enthalpy (Hm) were determined from the second heating step. The glass transition temperature Tg and storage modulus G’ at 23 °C were determined by dynamic mechanical analysis according to ISO 6721-7. The measurements were done in torsion mode on compression moulded samples (40x10x1 mm3) between -100 °C and +150 °C with a heating rate of 2 °C / min and frequency of 1 Hz. The Flexural Modulus was determined according to ISO 178 method A (3-point bending test) on 80 mm × 10 mm × 4 mm specimens. Following the standard, a test speed of 2 mm / min and a span length of 16 times the thickness was used. The testing temperature was 23±2 ° C. Injection moulding was carried out according to ISO 19069-2 using a melt temperature of 230 °C for all materials irrespective of material melt flow rate. Notched impact strength (NIS) The Charpy notched impact strength (NIS) was measured according to ISO 1791eA at +23 °C or -20 °C, using injection moulded bar test specimens of 80×10×4 mm³ prepared in accordance with ISO 19069-2 using a melt temperature of 230 °C for all materials irrespective of material melt flow rate. The xylene soluble fraction at room temperature (XCS, wt.-%): The amount of the polymer soluble in xylene was determined at 25 °C according to ISO 16152; 5thedition; 2005-07-01. VOC value The VOC value is determined according to VDA 278 October 2011 from injection moulded plaques. VDA 278 October 2011, Thermal Desorption Analysis of Organic Emissions for the Characterization of Non-Metallic Materials for Automobiles, VDA Verband der Automobilindustrie. According to the VDA 278 October 2011 the VOC value is defined as “the total of the readily volatile to medium volatile substances. It is calculated as toluene equivalent. The method described in this Recommendation allows substances in the boiling / elution range up to n-Pentacosane (C25) to be determined and analyzed.” FOG value: The FOG value is determined according to VDA 278 October 2011 from injection moulded plaques. According to the VDA 278 October 2011 the FOG value is defined as “the total of substances with low volatility which elute from the retention time of n-Tetradecane (inclusive). It is calculated as hexadecane equivalent. Substances having a boiling point in the boiling range of n-Alkanes “C14” to “C32” are determined and analyzed”. 2. Examples 2.1 Synthesis of heterophasic propylene-ethylene copolymer (HECO) For the polymerization process of HECO, a Ziegler-Natta type catalyst as used in for the inventive examples of WO2016 / 066446 A1 was employed (without any vinylcyclohexane prepolymerization). This catalyst was used in combination with triethyl-aluminium (TEAL) as co-catalyst and dicyclopenta dienyl-dimethoxy silane (Donor D) as external donor (This catalyst system is hereafter termed ZN-1). The subsequent polymerizations have been effected under the following conditions (Table 1). The powder obtained from Table 1 was compounded with 0.15 wt.-% of an antioxidant blend (available as Irganox B215FF from BASF AG, Germany; this is a 1:2-mixture of Pentaerythrityl-tetrakis(3-(3’,5’-di-tert. butyl-4-hydroxyphenyl)-propionate, CAS-no.6683- 19-8, and Tris (2,4-di-t-butylphenyl) phosphite, CAS-no.31570-04-4) and 0.05 wt.-% of Ca- stearate (available from Faci, Italy; CAS-no.1592-23-0) on a ZSK 58 twin screw extruder, with melt temperature of 205°C, production rate 200 kg / h. The properties of the pellets are shown in Table 1. Table 1 Polymerization conditions for the heterophasic propylene-ethylene copolymers HECO Prepolymerization Catalyst [-] ZN-1 [Co] / [ED] [mol / mol] 13.4 [Co] / [Ti] [mol / mol] 521.9 Temperature [°C] 20 Residence time [min] 18 Loop reactor Temperature [°C] 70 Split [wt.-%] 31.0 H2 / C3 [mol / kmol] 1.29 MFR2[g / 10 min] 9.5 XCS [wt.-%] 2.4 1stGas phase reactor Temperature [°C] 80 Split [wt.-%] 29.0 H2 / C3 [mol / kmol] 1.01 MFR2[g / 10 min] 2.96 MFR2 (of 1stGPR fraction) [g / 10 min] 0.85 XCS [wt.-%] 1.7 2ndGas phase reactor Temperature [°C] 70 Split [wt.-%] 40.0 H2 / C3 [mol / kmol] 343 C2 / C3 [mol / kmol] 288 XCS [wt.-%] 42.2 Final Properties (pellet) MFR2[g / 10 min] 2.58 C2 [wt.-%] 17.7 SF [wt.-%] 39.7 C2(SF) [wt.-%] 35.8 iV(SF) [dL / g] 2.32 CF [wt.-%] 60.3 C2(CF) [wt.-%] 6.9 iV(CF) [dL / g] 2.48 iV(total) [dL / g] 2.44 Tm [°C] 165 Hm [J / g] 66 Tc [°C] 122 Tg1 [°C] -44.8 Tg2 [°C] -0.1 2,1-regiodefects (matrix) [mol-%] 0.00 2.2 Propylene homopolymers (h-PP1, h-PP2, and h-PP3) The catalyst system used in the polymerization process for propylene homopolymer h-PP3 is the same Ziegler-Natta catalyst system used for HECO, with the exception that donor C (cyclohexylmethyldimethoxysilane) was used in place of donor D. This catalyst system is hereafter termed ZN-2. SSC-1 corresponds to ICS4 of WO 2020 / 239598 A1, which is based on metallocene catalyst rac-anti-dimethylsilanediyl[2-methyl-4,8-bis-(3’,5’-dimethylphenyl)-1,5,6,7-tetrahydro-s indacen-1-yl] [2-methyl-4-(3’,5’-dimethylphenyl)-5-methoxy-6-tert-butylinden-1-yl] zirconium dichloride. The subsequent polymerizations have been effected under the following conditions (Table 2). The powders obtained from Table 2 were each compounded with 0.15 wt.-% of an antioxidant blend (available as Irganox B215FF from BASF AG, Germany; this is a 1:2- mixture of Pentaerythrityl-tetrakis(3-(3’,5’-di-tert. butyl-4-hydroxyphenyl)-propionate, CAS- no.6683-19-8, and Tris (2,4-di-t-butylphenyl) phosphite, CAS-no.31570-04-4) and 0.05 wt.-% of Ca-stearate (available from Faci, Italy; CAS-no.1592-23-0) on a ZSK 58 twin screw extruder, with melt temperature of 205°C, production rate 200 kg / h. The properties of the pellets are shown in Table 2 Table 2 Polymerization conditions for the propylene homopolymers h-PP1 h-PP2 h-PP3 Prepolymerization Catalyst [-] SSC-1 SSC-1 ZN-2 [Co] / [ED] [mol / mol] - - 13.4 [Co] / [Ti] [mol / mol] - - 521.9 Temperature °C 19 19 28 Residence time min 22 22 20 Loop reactor Temperature °C 75 75 70 H2 / C3 ratio [mol / kmol] 0.38 1.20 4.0 Split [wt.-%] 54 100 100 MFR2 [g / 10 min] 59 1660 75 First GPR Temperature [°C] 80 - - H2 / C3 ratio [mol / kmol] 3.5 - - Split [wt.-%] 46 - - Pellet 2,1-regiodefects [mol-%] 0.50 0.50 0.00 MFR2 [g / 10min] 87 1660 75 Tm [°C] 155 155 162 XCS [wt.-%] 0.38 0.32 3.5 2.3 Compounding of Inventive and Comparative compositions The compositions were prepared based on the recipes indicated in Table 3 by compounding in a co-rotating twin-screw extruder Coperion ZSK 18 at 220 °C, at a production rate of 7 kg / h. The properties of the inventive and comparative compositions are given in Table 4. Table 3 Recipes for inventive and comparative examples IE1 IE2 CE1 HECO [wt.-%] 55 55 55 h-PP1 [wt.-%] 45 - - h-PP2 [wt.-%] - 45 - h-PP3 [wt.-%] - - 45 Table 4 Properties of the inventive and comparative compositions IE1 IE2 CE1 MFR2 [g / 10 min] 15.7 41 13.7 XCS [wt.-%] 22.8 22.6 23.8 VOC [µg / g] 10 23 52 FOG [µg / g] 68 115 240 Flexural Modulus [MPa] 949 1014 973 Charpy NIS (+23°C) [kJ / m2] 8.52 6.44 8.33 Charpy NIS (-20°C) [kJ / m2] 4.52 4.35 4.19 As can be seen from Table 4, all examples have a good balance of stiffness and impact strength. In addition, the inventive examples (in which a metallocene-catalyzed h-PP is employed) have considerably lower FOG and VOC values (i.e. reduced odour) relative to the comparative example (in which a ZN-catalyzed h-PP is employed), which is very important for automotive applications.

Claims

C L A I M S 1. A heterophasic polypropylene composition (PC) comprising: A) from 40.0 to 80.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a heterophasic propylene-ethylene copolymer (HECO), having a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 1.0 to 8.0 g / 10 min, comprising: i) a crystalline matrix (M) being a propylene homo- or copolymer that is free from 2,1-regiodefects, as determined by quantitative13C-NMR spectroscopic analysis; and ii) an amorphous propylene-ethylene elastomer (E), wherein the polymeric part of the heterophasic propylene-ethylene copolymer (HECO) has the following properties: a) a soluble fraction (SF) content, determined by CRYSTEX QC analysis, in the range from 20.0 to 50.0 wt.-%, based on the total weight of the heterophasic propylene ethylene copolymer (HECO), and a crystalline fraction (CF) content, determined by CRYSTEX QC analysis, in the range from 50.0 to 80.0 wt.-%, based on the total weight of the heterophasic propylene ethylene copolymer (HECO); b) an ethylene content of the CRYSTEX QC soluble fraction (C2(SF)), determined by CRYSTEX QC analysis, in the range from 20.0 to 60.0 wt.-%; and c) a total ethylene content (C2), determined by CRYSTEX QC analysis, in the range from 8 to 30 wt.-%, and B) from 20.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of a propylene homopolymer (h-PP) having the following properties: i) a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 20 to 3000 g / 10 min; ii) a content of 2,1-regiodefects, as determined by quantitative13C-NMR spectroscopic analysis, in the range from 0.05 to 1.20 mol-%,wherein the sum of the individual amounts of the heterophasic propylene-ethylene copolymer (HECO) and the propylene homopolymer (h-PP) is in the range from 90.0 to 100.0 wt.-%, relative to the total polymer content of the heterophasic polypropylene composition (PC), and wherein the heterophasic polypropylene composition (PC) has a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 5.0 to 100 g / 10 min and a content of volatile organic compounds (VOC), determined according to VDA 278 October 2011, in the range from 0 to 50 µg / g.

2. The heterophasic polypropylene composition (PC) according to claim 1, wherein the propylene homopolymer (h-PP) has a melting temperature (Tm), determined by differential scanning calorimetry (DSC), in the range from 145 to 160 °C.

3. The heterophasic polypropylene composition (PC) according to claim 1 or claim 2, wherein the propylene homopolymer (h-PP) has a xylene cold soluble content, determined according to ISO 16152, in the range from 0.0 to 1.0 wt.-%.

4. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, wherein the heterophasic propylene-ethylene copolymer (HECO) has an ethylene content of the CRYSTEX QC crystalline fraction (C2(CF)), determined by CRYSTEX QC analysis, in the range from 0.0 to 10.0 wt.-%.

5. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, wherein the heterophasic propylene-ethylene copolymer (HECO) has one or more, preferably all, of the following properties: a) an intrinsic viscosity of the CRYSTEX QC soluble fraction (iV(SF)), determined by CRYSTEX QC analysis, in the range from 1.50 to 5.00 dL / g; b) an intrinsic viscosity of the CRYSTEX QC crystalline fraction (iV(CF)), determined by CRYSTEX QC analysis, in the range from 1.50 to 3.00 dL / g; and c) a total intrinsic viscosity (iV), determined by CRYSTEX QC analysis, in the range from 1.50 to 3.00 dL / g.

6. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, wherein the crystalline matrix (M) of the heterophasic propylene- ethylene copolymer (HECO) is a homopolymer and / or has a melt flow rate (MFRM), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 1.0 to 10.0 g / 10 min.

7. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, wherein the heterophasic propylene-ethylene copolymer (HECO) has one or more, preferably all, of the following properties: a) a first melting temperature (Tm1), determined by differential scanning calorimetry (DSC), in the range from 160 to 170 °C; b) an enthalpy of fusion (Hm1) associated with the first melting temperature in the range from 50 to 80 J / g; and c) a crystallization temperature (Tc), determined by differential scanning calorimetry (DSC), in the range from 115 to 130 °C.

8. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, wherein the heterophasic propylene-ethylene copolymer (HECO) has one or more, preferably both, of the following properties: a) a first glass transition temperature (Tg1), determined according to ISO 6721 - 7, in the range from -65 to -40 °C; and b) a second glass transition temperature (Tg2), determined according to ISO 6721 -7, in the range from -5 to +5 °C.

9. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, wherein the crystalline matrix (M) of the heterophasic propylene- ethylene copolymer (HECO) is a homopolymer and is bimodal with respect to molecular weight, more preferably comprises: i) from 30 to 70 wt.-%, relative to the total weight of the crystalline matrix (M), of a first propylene homopolymer fraction (PP1) having a melt flowrate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 4.5 to 15.0 g / 10 min; and ii) from 30 to 70 wt.-%, relative to the total weight of the crystalline matrix (M), of a second propylene homopolymer fraction (PP2) having a melt flow rate (MFR2), determined according to ISO 1133 at 230 °C and 2.16 kg, in the range from 0.1 to 4.0 g / 10 min.

10. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, wherein the heterophasic propylene-ethylene copolymer (HECO) is not visbroken.

11. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, comprising, more preferably consisting of: A) from 40.0 to 80.0 wt.-%, more preferably from 45.0 to 70.0 wt.-%, yet more preferably from 50.0 to 65.0 wt.-%, most preferably from 50.0 to 60.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the heterophasic propylene-ethylene copolymer (HECO); B) from 20.0 to 60.0 wt.-%, more preferably from 30.0 to 55.0 wt.-%, yet more preferably from 35.0 to 50.0 wt.-%, most preferably from 40.0 to 50.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of the propylene homopolymer (h-PP); C) from 0.0 to 40.0 wt.-%, more preferably from 0.0 to 25.0 wt.-%, yet more preferably from 0.0 to 15.0 wt.-%, most preferably from 0.0 to 10.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more inorganic fillers (F); D) from 0.0 to 1.0 wt.-%, more preferably from 0.0 to 0.5 wt.-%, yet more preferably from 0.0 to 0.3 wt.-%, most preferably from 0.0 to 0.2 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more nucleating agents (NU); and E) from 0.0 to 5.0 wt.-%, relative to the total weight of the heterophasic polypropylene composition (PC), of one or more further additives different from the one or more inorganic fillers (F) and the one or more nucleating agents (NU).

12. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, having a xylene cold soluble content, determined according to ISO 16152, in the range from 10.0 to 30.0 wt.-%.

13. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, having one or more, preferably all, of the following properties: a) a flexural modulus, determined according to ISO 178 on 80×10×4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 800 to 2000 MPa; b) a Charpy Notched Impact Strength (NIS(+23°C)) measured according to ISO 179-1 eA at 23 °C on 80×10×4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 4.0 to 20 kJ / m2; and c) a low temperature Charpy Notched Impact Strength (NIS(-20°C)) measured according to ISO 179-1 eA at -20 °C on 80×10×4 mm3injection-moulded specimens prepared according to ISO 19069-2, in the range from 3.0 to 15 kJ / m2.

14. The heterophasic polypropylene composition (PC) according to any one of the preceding claims, having a content of semi-volatile organic compounds (FOG), determined according to VDA 278 October 2011, in the range from 0 to 200 µg / g.

15. An article, more preferably an automotive article, comprising at least 90 wt.-%, more preferably at least 95 wt.-%, most preferably at least 98 wt.-% of the heterophasic polypropylene composition (PC) according to any one of the preceding claims.

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