Polypropylene composition for fiber applications

Abstract

The present invention relates to a polypropylene composition comprising from 60.0 to 95.0 wt.-% of a heterophasic propylene-ethylene copolymer (A) and from 5.0 to 40.0 wt.- % of an elastomeric propylene-ethylene copolymer, whereby the polypropylene5 composition has a melt flow rate MFR2 of from 20.0 to 60.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C, an article comprising said polypropylene composition and the use of said polypropylene composition for the production of an article.

Description

[0001]Polypropylene composition for fiber applications The present invention relates to a polypropylene composition comprising from 60.0 to 95.0 wt.-% of a heterophasic propylene-ethylene copolymer (A) and from 5.0 to 40.0 wt.- % of an elastomeric propylene-ethylene copolymer, whereby the polypropylene composition has a melt flow rate MFR2of from 20.0 to 60.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C, an article comprising said polypropylene composition and the use of said polypropylene composition for the production of an article. Technical background Polypropylene, is used in many applications, like automotive application, packaging applications or fiber applications. For moulding applications, especially in the packaging field, and fiber applications, such as melt spun fibers or spunbonded fibers, processability is a key feature together with softness and toughness. However, there are technical limitations for reactor-made polypropylene resins with a superior balance of properties regarding processability in form of a high melt flow rate, softness in form of a low tensile modulus or flexural modulus and toughness in form of a high elongation at break. It is for example possible to produce a heterophasic propylene copolymer in a polymerization process, which comprises a matrix phase with a high melt flow rate and an elastomeric phase with a low molecular weight for obtaining a heterophasic propylene copolymer with a high overall melt flow rate. However, such heterophasic propylene copolymers with low molecular weight elastomeric phases tend to exhibit increased stickiness, which impairs the processability of the polypropylene composition during extrusion, especially in large scale extrusion. In the present invention it has surprisingly been found that a polypropylene composition comprising from 60.0 to 95.0 wt.-% of a heterophasic propylene-ethylene copolymer (A) and from 5.0 to 40.0 wt.-% of an elastomeric propylene-ethylene copolymer (B) and having a melt flow rate MFR2of from 20.0 to 60.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C, shows an improved balance of properties on behalf of processability in form of a high melt flow rate, softness in form of a low tensile modulus or flexural modulus and toughness in form of a high elongation at break and thereby showing a reduced stickiness during extrusion. Such a polypropylene composition is therefore suitable especially in moulding applications, such as injection moulding applications, and spinning applications, such as fiber applications, like melt spun fiber applications or spunbonded fiber applications. Summary of the invention In a first aspect the present invention relates to a polypropylene composition comprising (A) from 60.0 to 95.0 wt.-%, preferably from 65.0 to 90.0 wt.-%, more preferably from 68.0 to 85.0 wt.-%, based on the total weight of the polypropylene composition, of a heterophasic propylene-ethylene copolymer, which has ^ a soluble fraction (SF) content, determined by crystallization extraction (CRYSTEX) in the range of from 10.0 to 30.0 wt.-%, preferably from 12.5 to 25.0 wt.-% and most preferably from 14.0 to 22.5 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A), and ^ a crystalline fraction (CF) content, determined by crystallization extraction (CRYSTEX) in the range of from 70.0 to 90.0 wt.-%, preferably from 75.0 to 87.5 wt.-% and most preferably from 77.5 to 86.0 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A), ^ said soluble fraction having an ethylene content (C2(SF)), determined from crystallization extraction (CRYSTEX), calibrated by quantitative 13C nuclearmagnetic resonance (NMR) spectroscopy, of from 10.0 to 40.0 wt.-%, preferably from 15.0 to 35.0 wt.-%, most preferably from 20.0 to 32.5 wt.-%, based on the total amount of monomer units in the soluble fraction (SF) of the heterophasic propylene-ethylene copolymer (A), ^ said crystalline fraction having an ethylene content (C2(CF)), determined from crystallization extraction (CRYSTEX), calibrated by quantitative 13C nuclearmagnetic resonance (NMR) spectroscopy, of from 1.0 to 15.0 wt.-%, preferably from 2.0 to 10.0 wt.-%, most preferably from 3.0 to 8.5 wt.-%, based on the total amount of monomer units in the crystalline fraction (CF) of the heterophasic propylene-ethylene copolymer (A), and (B) from 5.0 to 40.0 wt.-%, preferably from 10.0 to 35.0 wt.-%, more preferably from 15.0 to 32.0 wt.-%, based on the total weight of the polypropylene composition, of an elastomeric propylene-ethylene copolymer, which has ^a total ethylene content, determined by quantitative 13C nuclear magneticresonance (NMR) spectroscopy, of from 3.0 to 25.0 wt.-%, preferably from 4.0 to 20.0 wt.-%, more preferably from 5.0 to 15.0 wt.-%, based on the total amount of monomer units in the elastomeric propylene-ethylene copolymer (B); ^ a weight average molecular weight Mw of from 10,000 to 50,000 g / mol, preferably from 15,000 to 40,000 g / mol, more preferably from 20,000 to 35,000 g / mol, determined by gel permeation chromatography (GPC) analysis; ^ a melting temperature Tm of from 60 to 120°C, preferably from 75 to 110°C, most preferably from 85 to 105°C, determined by differential scanning calorimetry (DSC) analysis according to ISO 11357 / part 3 / method C2; and ^ a glass transition temperature Tg of from -40 to -10°C, preferably from -35 to - 15°C, most preferably from -30 to -20°C, determined by dynamic mechanical analysis (DMA) according to ISO 6721-7; wherein the polypropylene composition has a melt flow rate MFR2of from 20.0 to 60.0 g / 10 min, preferably from 22.5 to 55.0 g / 10 min, more preferably from 25.0 to 50.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C. In a second aspect the present invention relates to an article comprising the polypropylene composition as described above or below. In a third aspect the present invention relates to the use of a polypropylene composition as described above or below for the production of an article, preferably a moulded article, like an injection moulded article, a spun article, like a fiber, such as a melt spun fiber or a spunbonded fiber. Definitions A heterophasic polypropylene is a propylene-based copolymer with a crystalline matrix phase, which can be a propylene homopolymer or a random copolymer of propylene and at least one alpha-olefin comonomer, and an elastomeric phase dispersed therein. The elastomeric phase can be a propylene copolymer with a high amount of comonomer, which is not randomly distributed in the polymer chain but are 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 respectively. A propylene homopolymer is a polymer, which 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 random copolymer is a copolymer of propylene monomer units and comonomer units in which the comonomer units are distributed randomly over the polypropylene chain. Thereby, a propylene random copolymer does not contain an elastomeric polymer phase dispersed therein. Usually, a propylene polymer comprising at least two propylene polymer fractions (components), which have been produced under different polymerization conditions resulting in different (weight average) molecular weights and / or different comonomer contents for the fractions, preferably produced by polymerizing in multiple polymerization stages with different polymerization conditions, is referred to as “multimodal”. The prefix “multi” relates to the number of different polymer fractions the propylene polymer is consisting of. As an example of multimodal propylene polymer, a propylene polymer consisting of two fractions only is called “bimodal”, whereas a propylene polymer consisting of three fractions only is called “trimodal”. A unimodal propylene polymer only consists of one fraction. Thereby, the term “different” means that the propylene polymer fractions differ from each other in at least one property, preferably in the weight average molecular weight – which can also be measured in different melt flow rates of the fractions – or comonomer content or both. An elastomer is a polymer with viscoelasticity and weak intermolecular forces. The term “elastomer” can be used interchangeably with “rubber”. Polyolefin based elastomers, such as polypropylene based elastomers, i.e. an elastomer with a molar majority of olefin monomer units, such as propylene monomer units, are usually thermoplastic elastomers. Thermoplastic elastomers have both thermoplastic and elastomeric properties. Polyolefin based elastomers, such as polypropylene based elastomers, usually show a low density and low viscosity. They can be propylene homopolymers or propylene-alpha olefin copolymers, such as propylene-ethylene copolymers. A specific class of polypropylene based elastomers are propylene homopolymers or propylene-alpha olefin copolymers, such as propylene-ethylene copolymers, which have been polymerized in the presence of a single site catalyst, usually in a solution polymerization process. Detailed description of the invention Polypropylene composition In a first aspect the present invention relates to a polypropylene composition comprising (A) from 60.0 to 95.0 wt.-%, preferably from 65.0 to 90.0 wt.-%, more preferably from 68.0 to 85.0 wt.-%, based on the total weight of the polypropylene composition, of a heterophasic propylene-ethylene copolymer, which has ^ a soluble fraction (SF) content, determined by crystallization extraction (CRYSTEX) in the range of from 10.0 to 30.0 wt.-%, preferably from 12.5 to 25.0 wt.-% and most preferably from 14.0 to 22.5 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A), and ^ a crystalline fraction (CF) content, determined by crystallization extraction (CRYSTEX) in the range of from 70.0 to 90.0 wt.-%, preferably from 75.0 to 87.5 wt.-% and most preferably from 77.5 to 86.0 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A), ^ said soluble fraction having an ethylene content (C2(SF)), determined from crystallization extraction (CRYSTEX), calibrated by quantitative 13C nuclearmagnetic resonance (NMR) spectroscopy, of from 10.0 to 40.0 wt.-%, preferably from 15.0 to 35.0 wt.-%, most preferably from 20.0 to 32.5 wt.-%, based on the total amount of monomer units in the soluble fraction (SF) of the heterophasic propylene-ethylene copolymer (A), ^ said crystalline fraction having an ethylene content (C2(CF)), determined from crystallization extraction (CRYSTEX), calibrated by quantitative 13C nuclearmagnetic resonance (NMR) spectroscopy, of from 1.0 to 15.0 wt.-%, preferably from 2.0 to 10.0 wt.-%, most preferably from 3.0 to 8.5 wt.-%, based on the total amount of monomer units in the crystalline fraction (CF) of the heterophasic propylene-ethylene copolymer (A), and (B) from 5.0 to 40.0 wt.-%, preferably from 10.0 to 35.0 wt.-%, more preferably from 15.0 to 32.0 wt.-%, based on the total weight of the polypropylene composition, of an elastomeric propylene-ethylene copolymer, which has ^a total ethylene content, determined by quantitative 13C nuclear magneticresonance (NMR) spectroscopy, of from 3.0 to 25.0 wt.-%, preferably from 4.0 to 20.0 wt.-%, more preferably from 5.0 to 15.0 wt.-%, based on the total amount of monomer units in the elastomeric propylene-ethylene copolymer (B); ^ a weight average molecular weight Mw of from 10,000 to 50,000 g / mol, preferably from 15,000 to 40,000 g / mol, more preferably from 20,000 to 35,000 g / mol, determined by gel permeation chromatography (GPC) analysis; ^ a melting temperature Tm of from 60 to 120°C, preferably from 75 to 110°C, most preferably from 85 to 105°C, determined by differential scanning calorimetry (DSC) analysis according to ISO 11357 / part 3 / method C2; and ^ a glass transition temperature Tg of from -40 to -10°C, preferably from -35 to - 15°C, most preferably from -30 to -20°C, determined by dynamic mechanical analysis (DMA) according to ISO 6721-7; wherein the polypropylene composition has a melt flow rate MFR2 of from 20.0 to 60.0 g / 10 min, preferably from 22.5 to 55.0 g / 10 min, more preferably from 25.0 to 50.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C. The polypropylene composition preferably comprises the heterophasic propylene- ethylene copolymer (A) in an amount of from 60.0 to 95.0 wt.-%, preferably from 65.0 to 90.0 wt.-%, more preferably from 68.0 to 85.0 wt.-%, and the elastomeric propylene- ethylene copolymer in an amount of from 5.0 to 40.0 wt.-%, preferably from 10.0 to 35.-0 wt.-%, more preferably from 15.0 to 32.0 wt.-%, all based on the total weight of the polypropylene composition. In the following the heterophasic propylene-ethylene copolymer (A) is also denoted component (A) and the elastomeric propylene-ethylene copolymer (B) is also denoted component (B). The polypropylene composition can further comprise polymeric components, which are different from the components (A) and (B), in an amount of preferably 0.0 to 5.0 wt.-% based on the total weight of the polypropylene composition. In a preferred embodiment the polymeric components of the polypropylene composition consist of components (A) and (B). Besides these polymeric components the polypropylene composition can comprise one or more additives in an amount of from 0.0 up to 5.0 wt.-%, based on the total weight of the polypropylene composition. The one or more additives are preferably selected from acid scavengers, antioxidants, processing aids, alpha nucleating agents, beta nucleating agents, etc. Such additives are commercially available and for example described in “Plastic Additives Handbook”, 6thedition 2009 of Hans Zweifel (pages 1141 to 1190). Usually, these additives are added in quantities of 1.0 to 50,000 ppm for each single component. The one or more additives can be added to the polymeric components in a blending step. Thereby, the one or more additives can be added to the polymeric components in form of master batches in which one or more additives are blended with a carrier polymer in concentrated amounts. Any optional carrier polymer is calculated to the amount of additives, based on the total weight of the propylene copolymer composition. The polypropylene composition preferably has a melting temperature Tm of from 130 to 150°C, more preferably from 135 to 148°C, still more preferably from 140 to 145°C, determined by DSC analysis according to ISO 11357 / part 3 / method C2. Further, the polypropylene composition preferably has a crystallization temperature Tc of from 80 to 120°C, more preferably from 85 to 115°C, still more preferably from 90 to 110°C, determined by DSC analysis according to ISO 11357 / part 3 / method C2. Still further, the polypropylene composition preferably has a heat of fusion of from 35 to 75 J / g, more preferably from 40 to 70 J / g, still more preferably from 45 to 65 J / g, determined by DSC analysis according to ISO 11357 / part 3 / method C2. Additionally, the polypropylene composition preferably has a xylene cold solubles (XCS) fraction in a total amount of from 15.0 to 45.0 wt.-%, more preferably 20.0 to 40.0 wt.-%, still more preferably from 25.0 to 35.0 wt.-%, based on the total weight of the polypropylene composition and determined according to ISO 16152. The polypropylene composition according to the present invention preferably has an improved balance of properties in behalf of processability in form of a high melt flow rate, softness in form of a low tensile modulus or flexural modulus and toughness in form of a high elongation at break. It has further surprisingly been found that upon extrusion no extraordinary stickiness is observed. The polypropylene composition has a melt flow rate MFR2of from 20.0 to 60.0 g / 10 min, preferably from 22.5 to 55.0 g / 10 min, more preferably from 25.0 to 50.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C. Further, the polypropylene composition preferably has a a tensile modulus of from 200 to 600 MPa, preferably from 300 to 550 MPa, more preferably from 350 to 500 MPa, determined according to ISO 527-2 (cross head speed 1 mm / min) using type 1A directly injection moulded test specimens according to ISO 527-2(1A). Still further, the polypropylene composition preferably has an elongation at break of from 600 to 1200%, preferably from 700 to 1100%, more preferably from 750 to 1000%, determined according to ISO 527-2 (cross head speed 50 mm / min) using type 1A directly injection moulded test specimens according to ISO 527-2(1A). Preferably, the polypropylene composition is prepared by melt blending the components (A) and (B), the optional additional polymeric components and the optional further additives, all as described above or below. In the following, the heterophasic propylene-ethylene copolymer (A) (abbreviated “copolymer of propylene (A)” or component (A)) and the elastomeric propylene-ethylene copolymer (B) (abbreviated component (B)) are described in more detail. Heterophasic propylene-ethylene copolymer (A) The heterophasic propylene-ethylene copolymer (A) is a copolymer consisting of propylene monomer units and ethylene monomer units. This means that the heterophasic propylene-ethylene copolymer (A) does not comprise any other comonomer units different from propylene and ethylene. The heterophasic propylene-ethylene copolymer (A) preferably has a total ethylenecontent, determined based on quantitative 13C-NMR 68spectroscopy, of from 4.0 to 15.0wt.-%, more preferably from 5.0 to 12.5 wt.-%, still more preferably from 6.0 to 10.0 wt.- %, based on the total weight of the heterophasic propylene-ethylene copolymer (A). Consequently, the heterophasic propylene-ethylene copolymer (A) has a total propylenecontent, determined based on quantitative 13C-NMR spectroscopy, of from 85.0 to 96.0wt.-%, more preferably from 87.5 to 95.0 wt.-%, still more preferably from 90.0 to 94.0 wt.-%, .-%, based on the total weight of the heterophasic propylene-ethylene copolymer (A). The total propylene content and the total ethylene content thereby make up 100 wt.-% of the heterophasic propylene-ethylene copolymer (A). The heterophasic propylene-ethylene copolymer (A) has a matrix phase and an elastomeric phase dispersed in said matrix phase. The matrix phase is a propylene-ethylene random copolymer. In the heterophasic propylene-ethylene copolymer (A) the matrix phase and the elastomeric phase usually cannot exactly be divided from each other. In order to characterize the matrix phase and the elastomeric phase of a heterophasic propylene copolymer several methods are known. One method is the crystallization extraction (CRYSTEX). This method is described below in the determination methods section. Thereby, the polymeric part of the polypropylene composition is characterized using trichlorobenzene (TCB) as a solvent. 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 compared to xylene extraction, 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 crystallization extraction (CRYSTEX) 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. Generally, the crystalline fraction (CF) content and the soluble (SF) content of a composition only relate to its polymeric components, i.e. without other components, like additives, which are insoluble and therefore not part of the dissolution and crystallization cycles as described below in the determination method. In the present case the heterophasic propylene-ethylene copolymer (A) is usually fully soluble in trichlorobenzene (TCB) so that the crystalline fraction (CF) content and the soluble (SF) content relate to the total content of the heterophasic propylene-ethylene copolymer (A). Thus, the crystalline fraction (CF) content and the soluble fraction (SF) content preferably make up 100 wt.-% of the heterophasic propylene-ethylene copolymer (A). The heterophasic propylene-ethylene copolymer (A) has a crystalline fraction (CF) content, determined by crystallization extraction (CRYSTEX), in the range from 70.0 to 90.0 wt.-%, preferably from 75.0 to 87.5 wt.-% and most preferably from 77.5 to 86.0 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A). Said crystalline fraction (CF) has an ethylene content (C2(CF)), determined fromcrystallization extraction (CRYSTEX), calibrated by quantitative 13C-NMR spectroscopy,in the range from 1.0 to 15.0 wt.-%, more preferably from 2.0 to 10.0 wt.-% and most preferably from 3.0 to 8.5 wt.-%, based on the total amount of monomer units in the crystalline fraction (CF). Further, said crystalline fraction (CF) preferably has an intrinsic viscosity (iV(CF)), determined from crystallization extraction (CRYSTEX), in the range from 1.65 to 2.90 dl / g, more preferably from 1.75 to 2.65 dl / g and most preferably from 1.90 to 2.40 dl / g. The heterophasic propylene-ethylene copolymer (A) has a soluble fraction (SF) content, determined by crystallization extraction (CRYSTEX), in the range from 10.0 to 30.0 wt.- %, preferably from 12.5 to 25.0 wt.-% and most preferably from 14.0 to 22.5 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A). Said soluble fraction (SF) has an ethylene content (C2(SF)), determined fromcrystallization extraction (CRYSTEX), calibrated by quantitative 13C-NMR spectroscopy,in the range from 10.0 to 40.0 wt.-%, preferably from 15.0 to 35.0 wt.-%, most preferably from 20.0 to 32.5 wt.-%, based on the total amount of monomer units in the soluble fraction (SF). Further, said soluble fraction (SF) preferably has an intrinsic viscosity (iV(SF)), determined from crystallization extraction (CRYSTEX), in the range from 0.90 to 1.90 dl / g, more preferably from 1.00 to 1.80 dl / g and most preferably from 1.15 to 1.70 dl / g. It is preferred that the crystalline fraction (CF) and the soluble fraction (SF) make up 100 wt.-% of the heterophasic propylene-ethylene copolymer (A). The heterophasic propylene-ethylene copolymer (A) preferably has a melt flow rate MFR2 of from 3.0 to 20.0 g / 10 min, more preferably from 4.0 to 15.0 g / 10 min, still more preferably from 5.0 to 10.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C. The heterophasic propylene-ethylene copolymer (A) preferably has a flexural modulus of more than 470 MPa, such as from 475 MPa to 800 MPa, more preferably of from 500 MPa to 750 MPa and most preferably of from 550 MPa to 700 MPa, determined according to ISO 178 method A. Further, the heterophasic propylene-ethylene copolymer (A) preferably has a Charpy notched impact strength at 23°C of from 4.0 to 15.0 kJ / m², more preferably from 5.0 to 13.0 kJ / m² and most preferably from 6.0 to 11.5 kJ / m², determined according to ISO 179-1 / 1eA. Furthermore, the heterophasic propylene-ethylene copolymer (A) preferably has a melting temperature Tm of from 130 to 150°C, more preferably from 135 to 147°C, most preferably from 140 to 145°C, determined by to DSC analysis according to ISO 11357 / part 3 / method C2. Further, the heterophasic propylene-ethylene copolymer (A) preferably has a crystallization temperature Tc of from 80 to 120°C, more preferably from 85 to 115°C, most preferably from 90 to 110°C, determined by to DSC analysis according to ISO 11357 / part 3 / method C2. The difference of the melting temperature to the crystallization temperature Tm-Tc is preferably in the range of from 20 to 70°C, more preferably from 25 to 60°C, most preferably from 30 to 55°C. The heterophasic propylene-ethylene copolymer (A) preferably has a total intrinsic viscosity of from 1.00 to 2.50 dl / g, more preferably from 1.25 to 2.35 dl / g, most preferably from 1.50 to 2.20 dl / g, determined based on ISO 1628-3. The heterophasic propylene-ethylene copolymer (A) preferably has a complex viscosity at a frequency of 100 rad / s eta*100 rad / sof from 500 to 700 Pa·s, more preferably from 550 to 650 Pa·s, most preferably from 570 to 630 Pa·s. The heterophasic propylene-ethylene copolymer (A) can be polymerized in a sequential multistage polymerization process, i.e. in a polymerization process in which two or more polymerization reactors are connected in series. Preferably, in the sequential multistage polymerization process, two or more, more preferably three or more, such as three or four, polymerization reactors are connected in series. The term “polymerization reactor” shall indicate that the main polymerization takes place. Thus, in case the process consists of two to four polymerization reactors, this definition does not exclude the option that the overall process comprises for instance a pre-polymerization step in a pre- polymerization reactor. The matrix phase of the heterophasic propylene-ethylene copolymer (A) is preferably polymerized in first polymerization reactor for producing a unimodal matrix phase or in the first and second polymerization reactor for producing a multimodal matrix phase. The elastomeric phase of the heterophasic propylene-ethylene copolymer (A) is preferably polymerized in the subsequent one or two polymerization reactor(s) in the presence of the matrix phase for producing a unimodal elastomeric phase or a multimodal elastomeric phase. Preferably, the polymerization reactors are selected from slurry phase reactors, such as loop reactors and / or gas phase reactors such as fluidized bed reactors, more preferably from loop reactors and fluidized bed reactors. A preferred sequential multistage polymerization process is a “loop-gas phase”-process, such as developed by Borealis A / S, Denmark (known as BORSTAR® technology) described e.g. in patent literature, such as in EP 0887379, WO 92 / 12182 WO 2004 / 000899, WO 2004 / 111095, WO 99 / 24478, WO 99 / 24479 or in WO 00 / 68315. A further suitable slurry-gas phase process is the Spheripol®process of LyondellBasell. Suitable sequential polymerization processes for polymerizing heterophasic propylene- ethylene copolymer (A) are e.g. disclosed in WO 2015 / 117948. The heterophasic propylene-ethylene copolymer (A) can be polymerized in the presence of a Ziegler-Natta catalyst. Suitable Ziegler-Natta catalysts are e.g. disclosed in WO 2015 / 117948. The heterophasic propylene-ethylene copolymer (A) is preferably subjected to a visbreaking step as e.g. described in WO 2013 / 092620 A1. This means that in the polymerization process a heterophasic propylene-ethylene copolymer (reactor product) is polymerized with a melt flow rate MFR2, which is lower than the final MFR2 of preferably from 3.0 to 20.0 g / 10 min, more preferably from 4.0 to 15.0 g / 10 min, still more preferably from 5.0 to 10.0 g / 10 min. The melt flow rate MFR2 of the reactor product is instead preferably in the range of from 0.5 to 6.0 g / 10 min, more preferably from 1.0 to 5.0 g / 10 min, still more preferably from 1.5 to 4.5 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C. The final MFR2of the heterophasic propylene-ethylene copolymer (A) is then preferably increased by vis-breaking. Heterophasic propylene copolymer resins suitable as heterophasic propylene-ethylene copolymer (A) are also commercially available. These resins are usually already additivated with stabilizer packages. Thus, when using commercially available resins as heterophasic propylene-ethylene copolymer (A) the addition of additives as described above might have to be adjusted to the already present additives. In case of a commercially available heterophasic propylene-ethylene copolymer (A) the above stated properties can be measured using a common measurement method or verified by the technical documentation provided by the supplier. Elastomeric The elastomeric propylene-ethylene copolymer (B) is a copolymer consisting of propylene monomer units and ethylene monomer units. This means that the elastomeric propylene-ethylene copolymer (B) does not comprise any other comonomer units different from propylene and ethylene. The elastomeric propylene-ethylene copolymer (B) has a total ethylene content,determined by quantitative 13C-NMR spectroscopy, of from 3.0 to 25.0 wt.-%, preferablyfrom 4.0 to 20.0 wt.-%, more preferably from 5.0 to 15.0 wt.-%, based on the total amount of monomer units in the elastomeric propylene-ethylene copolymer (B). Consequently, the elastomeric propylene-ethylene copolymer (B) has a total propylenecontent, determined by quantitative 13C-NMR spectroscopy, of from 75.0 to 97.0 wt.-%,more preferably from 80.0 to 96.0 wt.-%, still more preferably from 85.0 to 95.0 wt.-%, based on the total weight of the elastomeric propylene-ethylene copolymer (B). The total propylene content and the total ethylene content thereby make up 100 wt.-% of the elastomeric propylene-ethylene copolymer (B). Further, the elastomeric propylene-ethylene copolymer (B) has a melting temperature Tm of from 60 to 120°C, preferably from 75 to 110°C, most preferably from 85 to 105°C, determined by DSC analysis according to ISO 11357 / part 3 / method C2. Still further, the elastomeric propylene-ethylene copolymer (B) has a glass transition temperature Tg of from -40 to -10°C, preferably from -35 to -15°C, most preferably from -30 to -20°C, determined by dynamic mechanical analysis (DMA) according to ISO 6721-7. The elastomeric propylene-ethylene copolymer (B) preferably has a density of from 860 to 895 kg / m³, more preferably from 865 to 890 kg / m³, still more preferably from 870 to 885 kg / m³, determined according to ISO 1183. Further, the elastomeric propylene-ethylene copolymer (B) preferably has a melt flow rate MFR2 (230°C, 2.16 kg) of from 5,000 to 50,000 g / 10 min, more preferably from 10,000 to 40,000 g / 10 min, still more preferably from 12,500 to 35,000 g / 10 min and most preferably from 15,000 to 25,000 g / 10 min. Such high melt flow rates are usually not measurable using the usual standard measurements such as ISO 1133 or ASTM D 1238, but are estimated from the viscosity curves and extrapolated to MFR2at 230°C, 2.16 kg for comparison to other polypropylene resins. The elastomeric propylene-ethylene copolymer (B) preferably has a xylene cold solubles (XCS) fraction in a total amount of from 80.0 to 100.0 wt.-%, more preferably 85.0 to 99.9 wt.-%, still more preferably from 90.0 to 99.8 wt.-%, based on the total weight of the elastomeric propylene-ethylene copolymer (B) and determined according to ISO 16152. Further, the elastomeric propylene-ethylene copolymer (B) has a heat of fusion Hf of from 15 to 50 J / g, more preferably from 20 to 47 J / g, still more preferably from 25 to 45 J / g, determined by DSC analysis according to ISO 11357 / part 3 / method C2. Still further, the elastomeric propylene-ethylene copolymer (B) preferably has a viscosity at 190°C of from 500 to 10,000 mPas, more preferably from 750 to 7,500 mPas, most preferably from 1,000 to 5,000 mPas. The elastomeric propylene-ethylene copolymer (B) has a weight average molecular weight Mw of from 10,000 to 50,000 g / mol, preferably from 15,000 to 40,000 g / mol, more preferably from 20,000 to 35,000 g / mol, determined by GPC analysis. Further, the elastomeric propylene-ethylene copolymer (B) preferably has a polydispersity, PD, being the ratio of weight average molecular weight to number average molecular weight Mw / Mn, of from 1.2 to 3.5, more preferably from 1.5 to 3.2, still more preferably from 1.7 to 3.0. Elastomeric copolymers of propylene and ethylene suitable as elastomeric propylene- ethylene copolymer (B) are usually polymerized in the presence of a single site catalyst. Such elastomeric propylene-ethylene copolymers can be commercially available. One suitable example is Vistamaxx 8880 from ExxonMobil. In case of a commercially available elastomeric propylene-ethylene copolymer (B) the above stated properties can be measured using a common measurement method or verified by the technical documentation provided by the supplier. Article In a second aspect the present invention relates to an article comprising the polypropylene composition as described above or below. The article preferably comprises the polypropylene composition in an amount of from 90 to 100 wt.-%, more preferably from 95 to 100 wt.-%, based on the total weight of the article. In a preferred embodiment the article consists of the polypropylene composition. The article can be a moulded article, preferably an injection moulded article. The article can also be a spun article, preferably a fiber, such as a melt spun fiber or a spunbonded fiber or a non-woven fabric. Preferably all aspects of the polypropylene composition and its components as described above or below apply to the article of said second aspect. Use In a third aspect the present invention relates to the use of a polypropylene composition as described above or below for the production of an article, preferably a moulded article, like an injection moulded article, a spun article, like a fiber, such as a melt spun fiber or a spunbonded fiber, or a non-woven fabric. Preferably all aspects of the polypropylene composition and its components as well as the article all as described above or below apply to the article of said third aspect. Examples The following definitions of terms and determination methods apply for the above general description of the invention as well as to the below examples unless otherwise defined. 1. Measurement methods a) Melt Flow Rate (MFR2) The melt flow rate (MFR) was determined according to ISO 1133 and is 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 MFR2of polypropylene was determined at a temperature of 230 °C and a load of 2.16 kg. b) Density The density was measured according to ISO 1183-1:2004 Method A on compression moulded specimen prepared according to EN IS01872-2 (Feb 2007) and is given in kg / m3. c) Comonomer content Comonomer content quantification of poly(propylene-co-ethylene) copolymersQuantitative 13C{1H} NMR spectra were recorded in the solution-state using a BrukerAvance NEO 400 NMR spectrometer operating at 400.15 and 100.62 MHz for 1H and13C respectively. All spectra were recorded using a 13C optimised 10 mm extendedtemperature probe head at 125°C using nitrogen gas for all pneumatics. Approximately200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d2 (TCE-d2) alongwith chromium-(III)-acetylacetonate (Cr(acac)3) resulting in a 60 mM solution of relaxation agent in solvent {8} and with approximately 3 mg BHT (2,6-di-tert-butyl-4- methylphenol CAS 128-37-0) . To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatory 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 {3, 4}. A total of 6144 (6k) transients were acquired per spectra.Quantitative 13C{1H} NMR spectra were processed, integrated and relevant quantitativeproperties 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 {7}. The comonomer fraction was quantified using the method of Wang et. al. {6} throughintegration of multiple signals across the whole spectral region in the 13C{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 not be 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 to: E = 0.5 (Sββ + Sβγ + Sβδ + 0.5( Sαβ + Sαγ)) Through the use of this set of sites the corresponding integral equation becomes: E = 0.5 (IH+IG+ 0.5(IC+ ID)) using the same notation used in the article of Wang et al. {6}. Equations used for absolute propylene content were not modified. 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) ) Bibliographic references: 1) Busico, V., Cipullo, R., Prog. Polym. Sci.26 (2001) 443. 2) Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromolecules 30 (1997) 6251. 3) Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson.187 (2007) 225. 4) Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun.2007, 28, 1128. 5) Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev.2000, 100, 1253. 6) Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157. 7) Cheng, H. N., Macromolecules 17 (1984), 1950. 8) Singh, G., Kothari, A., Gupta, V., Polymer Testing 285 (2009), 475. 9) Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150. 10) Randall, J. Macromol. Sci., Rev. Macromol. Chem. Phys.1989, C29, 201. 11) Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev.2000, 100, 1253. d) Differential scanning calorimetry (DSC) analysis, melting temperature (Tm) and crystallization temperature (Tc): measured with a TA Instrument Q2000 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°C to +225°C. Crystallization temperature and crystallization enthalpy (Hc) were determined from the cooling step, while melting temperature and melting enthalpy (Hm) were determined from the second heating step. When a sample showed two or more melting temperatures and / or crystallization temperatures only the main melting temperature (at the maximum of Hm) and main crystallization temperature (at the maximum of Hc) were displayed in the accordant table. The difference of melting temperature and crystallization temperature (Tm-Tc) is given for the main melting temperature and the main crystallization temperature. e) Crystallization extraction (CRYSTEX) Note: Crystallization extraction (CRYSTEX) analyses the polymeric part of each component, with non-polymeric parts, such as any fillers or particulate pigments, not contributing to the reported CRYSTEX data presented. Determination of Crystalline and soluble fractions and their respective properties (iV and Ethylene content) The crystalline (CF) and soluble fractions (SF) of the polypropylene (PP) compositions as well as the comonomer content and intrinsic viscosities of the respective fractions were analyzed by use of the Crystex (crystallisation extraction) method. Potentialinstruments that can be used are Crystex QC or Crystex 42 (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 are 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) are achieved by means of an integrated infrared detector (IR4) and for the determination of the intrinsic viscosity (IV) an online 2-capillary viscometer is used. IR4 detector is a multiple wavelength detector measuring IR absorbance at two different bands (CH3 stretching vibration (centred at app.2960 cm-1) and the CH stretching vibration (2700-3000 cm-1) that are serving for the determination of the concentration and the Ethylene content in Ethylene-Propylene copolymers. IR4 detector is calibrated with series of 8 EP copolymers with known Ethylene content in the range of 2 wt.-% to 69 wt.-% (determined by 13C-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 concentration expected during Crystex analyses the following calibration equations were applied: The constants a to f for equation 1 and a to e for equation 2 were determined by using least square regression analysis. The CH3 / 1000C is converted to the ethylene content in wt.-% using following relationship: wt.-% (Ethylene in EP Copolymers) = 100 - CH3 / 1000TC * 0.3 (Equation 3) Amount 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 is achieved by testing various EP copolymers with XS content in the range 2-31 wt.-%. A linear calibration curve is used. 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 copolymers and PP polymers with iV = 2-4 dL / g. The determined calibration curve is linear. The samples to be analyzed were weighed out in concentrations of 10 mg / ml to 20 mg / ml. 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 170°C until complete dissolution is achieved with either constant stirring or gentle shaking. To avoid sample degradation, polymer solution was blanketed with the N2 atmosphere during dissolution. For PP composition containing inorganic fillers or pigments or any other non-TCB soluble polymeric substances removal of these was required. This can be done by hot filtration prior injection. A defined volume of the polymer 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 fraction was taking place. This process was repeated two times. During the first injection the whole sample was 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). f) Intrinsic viscosity (iV) The reduced viscosity (also known as viscosity number), ηred, and intrinsic viscosity, iV, were determined according to ISO 1628-3: “Determination of the viscosity of polymers in dilute solution using capillary viscometers”. Relative viscosities of a diluted polymer solution with concentration of 1 mg / ml and of the pure solvent (decahydronaphthalene stabilized with 200 ppm 2,6-bis(1,1- dimethylethyl)-4-methylphenol) were determined in an automated capillary viscometer (Lauda PVS1) equipped with 4 Ubbelohde capillaries placed in a thermostatic bath filled with silicone oil. The bath temperature was maintained at 135 °C. The sample was dissolved with constant stirring until complete dissolution was achieved (typically within 90 min). The efflux time of the polymer solution as well as of the pure solvent are measured several times until three consecutive readings did not differ for more than 0.2s (standard deviation). The relative viscosity of the polymer solution was determined as the ratio of averaged efflux times in seconds obtained for both, polymer solution and solvent: ηrel [dimensionless] Reduced viscosity (ηred) is calculated using the equation: where C is the polymer solution concentration at 135°C: C=m , V ^and m is the polymer mass, V is the solvent volume, and γ is the ratio of solventdensities at 20°C and 135°C (γ=ρ20 / ρ135=1.107). The calculation of intrinsic viscosity iV is performed by using the Schulz-Blaschke equation from the single concentration measurement: where K is a coefficient depending on the polymer structure and concentration. For calculation of the approximate value for IV, K=0.27. g) Flexural Modulus The flexural modulus was determined acc. 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 200°C for all materials irrespective of material melt flow rate. h) Tensile test The tensile properties (tensile modulus and elongation at break) were determined according to ISO 527-2 test specimens. Following the standard, a test speed of 1mm / min was used for tensile modulus and 50mm / min for all other properties. The testing temperature was +23±2°C. Injection moulding was carried out according to ISO 19069-2. i) Charpy notched impact strength The Charpy notched impact strength (NIS) was measured according to ISO 1791eA at +23 °C and -20°C using injection moulded bar test specimens of 80×10×4 mm³ prepared in accordance with ISO 19069-2. j) Xylene cold solubles (XCS) content The amount of the polymer soluble in xylene was determined at 25 °C according to ISO 16152; 5thedition; 2005-07-01. k) Molar mass Molar mass averages (Mz, Mw and Mn) and molecular weight distribution (MWD), i.e. Mw / Mn, were determined by Gel Permeation Chromatography (GPC) according to ISO 16014-4:2003 and ASTM D 6474-99 using the following formulas: where Ai and Mi are the chromatographic peak slice area and polyolefin molecular weight (MW). A PolymerChar GPC instrument, equipped with infrared (IR) detector was used with 3 x Olexis and 1x Olexis Guard columns from Polymer Laboratories and 1,2,4- trichlorobenzene (TCB, stabilized with 250 mg / l 2,6-Di-tert-butyl-4-methyl-phenol) as solvent at 160 °C and at a constant flow rate of 1 ml / min.200 µL of sample solution were injected per analysis. The column set was calibrated using universal calibration (according to ISO 16014-2:2003) with at least 15 narrow MWD polystyrene (PS) standards in the range of 0.5 kg / mol to 11500 kg / mol. Mark Houwink constants used for PS, PE and PP are as described per ASTM D 6474-99. All samples were prepared by dissolving 5.0 to 9.0 mg of polymer in 8 ml (at 160 °C) of stabilized TCB (same as mobile phase) for 2.5 hours for PP or 3 hours for PE at 160 °C under continuous gentle shaking in the autosampler of the GPC instrument. l) Glass transition temperature (Tg) Glass transition temperature Tg was determined by dynamic mechanical analysis (DMA) 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 a frequency of 1 Hz. Tg was determined from the curve of the loss angle (tan(δ)). m) Rheological measurements Dynamic Shear Measurements (frequency sweep measurements) The characterisation of melt of polymer composition or polymer as given above or below in the context by dynamic shear measurements complies with ISO standards 6721-1 and 6721-10. The measurements were performed on an Anton Paar MCR501 stress controlled rotational rheometer, equipped with a 25 mm parallel plate geometry. Measurements were undertaken on compression moulded plates, using nitrogen atmosphere and setting a strain within the linear viscoelastic regime. The oscillatory shear tests were done at 190 °C applying a frequency range between 0.01 and 600 rad / s and setting a gap of 1.3 mm. In a dynamic shear experiment the probe is subjected to a homogeneous deformation at a sinusoidal varying shear strain or shear stress (strain and stress controlled mode, respectively). On a controlled strain experiment, the probe is subjected to a sinusoidal strain that can be expressed by^^(^^) = ^^0 sin(^^^^) (1)If the applied strain is within the linear viscoelastic regime, the resulting sinusoidal stress response can be given by ^^0 and ^^0 are the stress and strain amplitudes, respectively^^ is the angular frequency^^ is the phase shift (loss angle between applied strain and stress response)t is the time Dynamic test results are typically expressed by means of several different rheological functions, namely the shear storage modulus G’, the shear loss modulus, G’’, the complex shear modulus, G*, the complex shear viscosity, η*, the dynamic shear viscosity, η', the out-of-phase component of the complex shear viscosity η” and the loss tangent, tan δ which can be expressed as follows: ^^′ = ^^0^^0 cos^^ [Pa] (3) ^^∗ = ^^′ + ^^^^′′ [Pa] (5)η∗ = η′ − iη′′ [Pa∙s] (6) The determination of so-called Shear Thinning Index, which correlates with MWD and is independent of Mw, is done as described in equation 9. Eta* for (G* = x kPa) SHI(x / y)= Eta* for (G* = y kPa (9) For example, the SHI(2 / 100) is defined by the value of the complex viscosity, in Pa∙ s, determined for a value of G* equal to 1 kPa, divided by the value of the complex viscosity, in Pa∙ s, determined for a value of G* equal to 100 kPa. The values of storage modulus (G'), loss modulus (G"), complex modulus (G*) and complex viscosity (η*) were obtained as a function of frequency (ω). Thereby, e.g. η*100rad / s(eta*100rad / sor eta100) is used as abbreviation for the complex viscosity at the frequency of 100 rad / s. The polydispersity index, PI, is defined by equation 10.105PI =^^′(^^ , ωCOP^^^^^^) = ω for (G’= G'’) (10)where ωCOPis the cross-over angular frequency, determined as the angular frequency for which the storage modulus, G', equals the loss modulus, G". The values are determined by means of a single point interpolation procedure, as defined by Rheoplus software. In situations for which a given G* value is not experimentally reached, the value is determined by means of an extrapolation, using the same procedure as before. In both cases (interpolation or extrapolation), the option from Rheoplus "Interpolate y-values to x-values from parameter" and the "logarithmicinterpolation type" were applied. References: [1] Rheological characterization of polyethylene fractions” Heino, E.L., Lehtinen, A., Tanner J., Seppälä, J., Neste Oy, Porvoo, Finland, Theor. Appl. Rheol., Proc. Int. Congr. Rheol, 11th (1992), 1, 360-362 [2] The influence of molecular structure on some rheological properties of polyethylene”, Heino, E.L., Borealis Polymers Oy, Porvoo, Finland, Annual Transactions of the Nordic Rheology Society, 1995.). [3] Definition of terms relating to the non-ultimate mechanical properties of polymers, Pure & Appl. Chem., Vol.70, No.3, pp.701-754, 1998. 2. Production of the polypropylene compositions The following resins were used for the preparation of the propylene copolymer compositions of the examples: a) Polymerization of the heterophasic propylene copolymers HECO1 and HECO2, ^ Catalyst The catalyst used in the polymerization process for the heterophasic propylene copolymers HECO1 and HECO2 is a Ziegler-Natta catalyst, which is described in the example section of WO 2015 / 117948. As co-catalyst triethyl-aluminium (TEAL) and as donor dicyclo pentyl dimethoxy silane (D-donor) was used. ^ Powder A and B: The heterophasic propylene copolymer powders A and B were produced in a Borstar™ pilot plant in the presence of the above described polymerization catalyst using one liquid-phase loop reactor and two gas phase reactors connected in series under conditions as shown in Table 1. The first reaction zone was a loop reactor and the second and third reaction zones were gas phase reactors. The matrix phase was polymerized in the loop and first gas phase reactor and the elastomeric phase was polymerized in the second gas phase reactor. Table 1: Polymerization of heterophasic propylene copolymer powder A and B: POWDER A POWDER BPrepolymerization Temperature [°C] 20 20Residence time [h] 0.40 0.20TEAL / Ti ratio [mol / mol] 125 250Donor / Ti ratio [mol / mol] 17 20Loop Split (Loop + Prepoly) [%] 37.2 48.0Temperature [°C] 70 70C2 / C3 ratio [mol / kmol] 22.4 16.3H2 / C3 ratio [mol / kmol] 1.8 19.5MFR (230°C / 2.16kg) [g / 10 min] 3.9 35C2 content [wt.-%] 2.5 1.8GPR 1 Split (GPR1) [%] 52.5 50.0Temperature [°C] 85 85C2 / C3 ratio [mol / kmol] 24.6 12.2H2 / C3 ratio [mol / kmol] 7.5 78MFR (230°C / 2.16kg) [g / 10 min] 3.3 35C2 content [wt.-%] 4.4 1.8GPR 2 Split (GPR2) [%] 10.3 12.0Temperature [°C] 75 75C2 / C3 ratio [mol / kmol] 392 413H2 / C3 ratio [mol / kmol] 152 165MFR (230°C / 2.16kg) g / 10 min 3.9 25C2 content [wt.-%] 7.9 5.5XCS [wt.-%] 18.0 16^ Preparation of HECO1 The powder A from the polymerization reaction and 0.12 wt.-% of additive package 1 were compounded in a twin screw extruder together with a stabilizer package to obtain the polypropylene composition of HECO1. During compounding of HECO1, the composition was vis-broken to a melt flow rate MFR2(230°C, 2.16 kg) of 7.0 g / 10 min with Trigonox 101. Additive package 1 consisted of 25.6 wt.-% Pentaerythrityl-tetrakis(3-(3’,5’-di-tert. butyl- 4-hydroxyphenyl)-propionate (CAS-No.6683-19-8), 51.3 wt.-% Tris (2,4-di-t-butylphenyl) phosphite (CAS-No.31570-04-4) and 23.1 wt.-% synthetic hydrotalcite (CAS-No.11097- 59-9), all commercially available from a variety of companies. ^ Preparation of HECO2 The powder B from the polymerization reaction and 15 wt.-% of the low density polyethylene (LDPE) grade CA9150 of Borealis AG, characterized by a density of 915 kg / m³ and an MFR2(190°C / 2.16 kg) of 15 g / 10 min, as well as 0.38 wt.-% of additive package 2 were compounded in a twin screw extruder together with a stabilizer package to obtain the polypropylene composition of HECO2. No visbreaking was done. Additive package 2 consisted of 15.6 wt.-% Pentaerythrityl-tetrakis(3-(3’,5’-di-tert. butyl- 4-hydroxyphenyl)-propionate (CAS-No.6683-19-8), 15.6 wt.-% Tris (2,4-di-t-butylphenyl) phosphite (CAS-No.31570-04-4), 15.6 wt.-% Ca-stearate (CAS-No.1592-23-0) and 53.2 wt.-% 1,3 : 2,4 Bis(3,4-dimethylbenzylidene) sorbitol (CAS-No.135861-56-2), all commercially available from a variety of companies. The properties of HECO1 are listed in Table 2 below. Table 2: Properties of HECO1 and HECO2 HECO1 HECO2MFR2 [g / 10 min] 7.0 25Flex. modulus [MPa] 686 780Charpy NIS 23°C [kJ / m³] 6.5 6.0Charpy NIS -20°C [kJ / m²] 0.97 1.8Tm [°C] 143 155Tc [°C] 97 126Tm-Tc [°C] 46 29C2 total (CRYSTEX) [wt.-%] 7.8 n.d.iV total (CRYSTEX) [dl / g] 1.91 n.d.CF (CRYSTEX) [wt.-%] 82.8 n.d.C2 of CF (CRYSTEX) [wt.-%] 4.1 n.d.iV of CF (CRYSTEX) [dl / g] 2.04 n.d.SF (CRYSTEX) [wt.-%] 17.2 n.d.C2 of SF(CRYSTEX) [wt.-%] 26.1 n.d.iV of SF(CRYSTEX) [dl / g] 1.29 n.d.Eta* at 100 rad / s [Pa·s] 602 350n.d. = not determined For the production of the polypropylene compositions of the inventive example IE1 and comparative example CE1 the compounded pellets of HECO1 was compounded in a second compounding step in a ZSK 18 twin extruder to a composition as described in Table 3. As R-PP1 the polymerization product of random propylene-co-ethylene copolymer of IE2 of EP 2999721 A1 with a melt flow rate MFR2of 40.0 g / 10 min and an ethylene content of 5.2 mol-% was used. For the production of the polymer composition of the comparative example CE2, 84.88 wt.-% powder B, 0.12 wt.--% of additive package 1 and 15 wt.-% of Queo 8230 were compounded in ZSK 18 twin extruder to a composition as described in Table 3 An overview of the components of the polypropylene compositions IE1, CE1, CE2 and CE3 is shown in Table 3. The properties of IE1, CE1, CE2, CE3 are shown in Table 4. Table 3: Components of the polypropylene compositions IE1, CE1, CE2 and CE3 IE1 CE1 CE2 CE3HECO1 70 100 - -R-PP1 - - 85 -HECO2 - - - 100Vistamaxx 8880 30 - - -Queo 8230 - - 15 -^ Vistamaxx 8880 is a single-site catalysed poly(propylene-co-ethylene) elastomer having a melt flow rate MFR2 of about 20000 g / 10 min (estimated from the viscosity curve), a viscosity at 190°C of 1200 mPas, a density of 879 kg / m³, glass transition temperature Tg of -22°C, melting temperature Tm of 98°C, heat of fusion Hf of 38 J / g, weight average molecular weight Mw of 26900 g / mol, PDI of 2.2, XCS fraction of 99.4 wt.-% and ethylene content of 6.4 wt.-%, commercially available from ExxonMobil, USA. ^ Queo 8230 is a single-site catalyzed poly(ethylene-co-1-octene) elastomer having a melt flow rate MFR2of about 30 g / 10 min (2.16 kg, 190°C, ISO 1133), a density of 882 kg / m³ and a melting temperature of 76°C, commercially available from Borealis AG, Austria. Table 4: Properties of the polypropylene compositions IE1, CE1, CE2 and CE3 IE1 CE1 CE2 CE3MFR2 g / 10 min 33 7 55 25Tm °C 142 142 144 155Hf J / g 58 70 69 87Tc °C 101 103 103 n.m.Tensile modulus MPa 442 612 735 996Elongation at break % 866 556 553 420n.m. = not measured The polypropylene composition of inventive example IE1 shows an improved balance of properties in regard of high flowability in form of high melt flow rate, softness in form of low tensile modulus and toughness in form of high elongation at break. No stickiness during extrusion is observed for the polypropylene composition of IE1.

Claims

Claims 1. A polypropylene composition comprising (A) from 60.0 to 95.0 wt.-%, preferably from 65.0 to 90.0 wt.-%, more preferably from 68.0 to 85.0 wt.-%, based on the total weight of the polypropylene composition, of a heterophasic propylene-ethylene copolymer, which has ^ a soluble fraction (SF) content, determined by crystallization extraction (CRYSTEX) in the range of from 10.0 to 30.0 wt.-%, preferably from 12.5 to 25.0 wt.-% and most preferably from 14.0 to 22.5 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A), and ^ a crystalline fraction (CF) content, determined by crystallization extraction (CRYSTEX) in the range of from 70.0 to 90.0 wt.-%, preferably from 75.0 to 87.5 wt.-% and most preferably from 77.5 to 86.0 wt.-%, based on the total weight amount of the heterophasic propylene-ethylene copolymer (A), ^ said soluble fraction having an ethylene content (C2(SF)), determined from crystallization extraction (CRYSTEX), calibrated by quantitative 13C nuclearmagnetic resonance (NMR) spectroscopy, of from 10.0 to 40.0 wt.-%, preferably from 15.0 to 35.0 wt.-%, most preferably from 20.0 to 32.5 wt.-%, based on the total amount of monomer units in the soluble fraction (SF) of the heterophasic propylene-ethylene copolymer (A), ^ said crystalline fraction having an ethylene content (C2(CF)), determined from crystallization extraction (CRYSTEX), calibrated by quantitative 13Cnuclear magnetic resonance (NMR) spectroscopy, of from 1.0 to 15.0 wt.-%, preferably from 2.0 to 10.0 wt.-%, most preferably from 3.0 to 8.5 wt.-%, based on the total amount of monomer units in the crystalline fraction (CF) of the heterophasic propylene-ethylene copolymer (A), and (B) from 5.0 to 40.0 wt.-%, preferably from 10.0 to 35.0 wt.-%, more preferably from 15.0 to 32.0 wt.-%, based on the total weight of the polypropylene composition, of an elastomeric propylene-ethylene copolymer, which has ^a total ethylene content, determined by quantitative 13C nuclear magneticresonance (NMR) spectroscopy, of from 3.0 to 25.0 wt.-%, preferably from 4.0 to 20.0 wt.-%, more preferably from 5.0 to 15.0 wt.-%, based on the total amount of monomer units in the elastomeric propylene-ethylene copolymer (B);^ a weight average molecular weight Mw of from 10,000 to 50,000 g / mol, preferably from 15,000 to 40,000 g / mol, more preferably from 20,000 to 35,000 g / mol, determined by gel permeation chromatography (GPC) analysis; ^ a melting temperature Tm of from 60 to 120°C, preferably from 75 to 110°C, most preferably from 85 to 105°C, determined by differential scanning calorimetry (DSC) analysis according to ISO 11357 / part 3 / method C2; and ^ a glass transition temperature Tg of from -40 to -10°C, preferably from -35 to -15°C, most preferably from -30 to -20°C, determined by dynamic mechanical analysis (DMA) according to ISO 6721-7; wherein the polypropylene composition has a melt flow rate MFR2of from 20.0 to 60.0 g / 10 min, preferably from 22.5 to 55.0 g / 10 min, more preferably from 25.0 to 50.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C.

2. The polypropylene composition according to claim 1, wherein the soluble fraction of the heterophasic propylene-ethylene copolymer (A) has an intrinsic viscosity (iV(SF)), determined from crystallization extraction (CRYSTEX), in the range from 0.90 to 1.90 dl / g, preferably from 1.00 to 1.80 dl / g and more preferably from 1.15 to 1.70 dl / g, and / or the crystalline fraction of the heterophasic propylene-ethylene copolymer (A) has an intrinsic viscosity (iV(CF)), determined from crystallization extraction (CRYSTEX), in the range from 1.65 to 2.90 dl / g, more preferably from 1.75 to 2.65 dl / g and most preferably from 1.90 to 2.40 dl / g.

3. The polypropylene composition according to claims 1 or 2, wherein the heterophasic propylene-ethylene copolymer (A) has one or more or all of the following properties: ^a total ethylene content, determined by quantitative 13C-NMR spectroscopy, offrom 4.0 to 15.0 wt.-%, preferably from 5.0 to 12.5 wt.-%, more preferably from 6.0 to 10.0 wt.-%, based on the total weight of the heterophasic propylene- ethylene copolymer (A);^ a melt flow rate MFR2of from 3.0 to 20.0 g / 10 min, preferably from 4.0 to 15.0 g / 10 min, more preferably from 5.0 to 10.0 g / 10 min, determined according to ISO 1133 at 2.16 kg and 230°C; ^ a melting temperature Tm of from 130 to 150°C, preferably from 135 to 147°C, more preferably from 140 to 145°C, determined by DSC analysis according to ISO 11357 / part 3 / method C2; ^ a crystallization temperature Tc of from 80 to 120°C, preferably from 85 to 115°C, more preferably from 90 to 110°C, determined by DSC analysis according to ISO 11357 / part 3 / method C2; ^ a difference of the melting temperature to the crystallization temperature Tm-Tc in the range of from 20 to 70°C, preferably from 25 to 60°C, more preferably from 30 to 55°C; ^ a total intrinsic viscosity of from 1.00 to 2.50 dl / g, preferably from 1.25 to 2.35 dl / g, more preferably from 1.50 to 2.20 dl / g, determined according to ISO 1628- 3; ^ a complex viscosity at a frequency of 100 rad / s eta*100 rad / s of from 500 to 700 Pa·s, preferably from 550 to 650 Pa·s, more preferably from 570 to 630 Pa·s.

4. The polypropylene composition according to any one of claims 1 to 3, wherein the heterophasic propylene-ethylene copolymer (A) has one or more or all of the following properties: ^ a flexural modulus of more than 470 MPa, such as from 475 MPa to 800 MPa, preferably of from 500 MPa to 750 MPa and more preferably of from 550 MPa to 700 MPa, determined according to ISO 178 method A; ^ a Charpy notched impact strength at 23°C of from 4.0 to 15.0 kJ / m², preferably from 5.0 to 13.0 kJ / m² and more preferably from 6.0 to 11.5 kJ / m², determined according to ISO 179-1 / 1eA.

5. The polypropylene composition according to any one of claims 1 to 4, wherein the elastomeric propylene-ethylene copolymer (B) has one or more or all of the following properties: ^ a melt flow rate MFR2 of from 5,000 to 50,000 g / 10 min, preferably from 10,000 to 40,000 g / 10 min, more preferably from 12,500 to 35,000 g / 10 min and most preferably from 15,000 to 25,000 g / 10 min;^ a density of from 860 to 895 kg / m³, preferably from 865 to 890 kg / m³, more preferably from 870 to 885 kg / m³, determined according to ISO 1183; ^ a xylene cold solubles (XCS) fraction in a total amount of from 80.0 to 100.0 wt.-%, preferably 85.0 to 99.9 wt.-%, more preferably from 90.0 to 99.8 wt.-%, based on the total weight of the elastomeric propylene-ethylene copolymer (B) and determined according to ISO 16152; ^ a heat of fusion Hf of from 15 to 50 J / g, preferably from 20 to 47 J / g, more preferably from 25 to 45 J / g, determined by DSC analysis according to ISO 11357 / part 3 / method C2; ^ a viscosity at 190°C of from 500 to 10,000 mPas, preferably from 750 to 7,500 mPas, most preferably from 1,000 to 5,000 mPas.

6. The polypropylene composition according to any one of claims 1 to 5, wherein the elastomeric propylene-ethylene copolymer (B) has a polydispersity PD, being the ratio of weight average molecular weight to number average molecular weight Mw / Mn, of from 1.2 to 3.5, preferably from 1.5 to 3.2, more preferably from 1.7 to 3.

0.

7. The polypropylene composition according to any one of claims 1 to 6 having a xylene cold solubles (XCS) fraction in a total amount of from 15.0 to 45.0 wt.-%, preferably 20.0 to 40.0 wt.-%, more preferably from 25.0 to 35.0 wt.-%, based on the total weight of the polypropylene composition and determined according to ISO 16152.

8. The polypropylene composition according to any one of claims 1 to 7 having one or more or all of the following properties: ^ a melting temperature Tm of from 130 to 150°C, preferably from 135 to 148°C, more preferably from 140 to 145°C; ^ a crystallization temperature Tc of from 80 to 120°C, preferably from 85 to 115°C, more preferably from 90 to 110°C, ^ a heat of fusion of from 35 to 75 J / g, preferably from 40 to 70 J / g, more preferably from 45 to 65 J / g, all determined by DSC analysis according to ISO 11357 / part 3 / method C2.

9. The polypropylene composition according to any one of claims 1 to 8 having a tensile modulus of from 200 to 600 MPa, preferably from 300 to 550 MPa, more preferably from 350 to 500 MPa, and / or an elongation at break of from 600 to 1200%, preferably from 700 to 1100%, more preferably from 750 to 1000%, both determined according to ISO 527-2 (cross head speed 1 mm / min or 50 mm / min, respectively) using type 1A directly injection moulded test specimens according to ISO 527-2(1A).

10. An article comprising the polypropylene composition according to any one of claims 1 to 9.

11. The article according to claim 10 comprising the polypropylene composition in an amount of from 90 to 100 wt.-%, preferably from 95 to 100 wt.-%, based on the total weight of the article, more preferably consists of the polypropylene composition.

12. The article according to claims 10 or 11, being a moulded article, like an injection moulded article, a spun article, like a fiber, such as a melt spun fiber or a spunbonded fiber, or a non-woven fabric.

13. The use of a polypropylene composition according to any one of claims 1 to 9 for the production of an article, preferably a moulded article, like an injection moulded article, a spun article, like a fiber, such as a melt spun fiber or a spunbonded fiber, or a non-woven fabric.

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