WO2021078857A1

WO2021078857A1 - Heterophasic polypropylene composition with improved stiffness and impact behaviour

Info

Publication number: WO2021078857A1
Application number: PCT/EP2020/079749
Authority: WO
Inventors: Jingbo Wang; Markus Gahleitner; Klaus Bernreitner; Pauli Leskinen
Original assignee: Borealis Ag
Priority date: 2019-10-23
Filing date: 2020-10-22
Publication date: 2021-04-29

Abstract

The present invention relates to a heterophasic polypropylene composition comprising two different heterophasic propylene copolymers. The heterophasic polypropylene composition has higher stiffness, than expected from the mere weighted average of the flexural moduli of the starting components. The heterophasic polypropylene composition has also an improved property profile, e.g. improved balance of stiffness and impact behaviour while having lower amounts of soluble fractions.

Description

Heterophasic Polypropylene Composition with Improved Stiffness and Impact Behaviour

The present invention relates to a heterophasic polypropylene composition comprising two different heterophasic propylene copolymers.

The heterophasic polypropylene composition has higher stiffness, than expected from the mere weighted average of the flexural moduli of the starting components.

The heterophasic polypropylene composition has high impact behaviour and high puncture resistance both +23 °C as well at -20 °C, as well as a high ratio of puncture resistance in relation to the amount of the fraction soluble in cold xylene (XCS).

Background Information

Heterophasic propylene copolymers are widely used in the packaging industry, due to their excellent combination of stiffness and impact behaviour. One can find the application of heterophasic propylene copolymers in many aspects of daily life. Still, there is the desire within the polymer and packaging industry to improve the available heterophasic polypropylene compositions in view of mechanical properties, especially having a well- balanced stiffness / impact relation, and the amount of extractable fractions.

Polymers with higher stiffness allow the production of articles with reduced wall thickness. At the same time, said polymers must not become brittle.

It is well known, that the amorphous rubbery phase of heterophasic propylene copolymers, is essential for providing impact properties, but can render the polymer softer and due to its extractability in solvents negatively impact the amount of soluble fractions. So, improving one property cannot be done without any sacrifice on the expense of the others.

Description of the prior art:

EP 2275485 A1 covers a heterophasic polypropylene composition comprising (A) 45 to 70 wt.-% of a propylene homo- or copolymer matrix with an MFR230/2.16 of ≥ 80 g/10 min and (B) 25 to 40 wt.-% of an elastomeric propylene-ethylene copolymer, having an intrinsic viscosity IV according to ISO 1628, with decalin as solvent, of at least 3.3 dl/g and an ethylene content of 20 to 50 wt.-%, (C) 0 - 15 wt-% of an elastomeric ethylene/alpha- olefin random copolymer, and (D) 3 - 25 parts per weight of inorganic filler, the heterophasic polypropylene compositions having a total MFR2 of at least 5 g/10 min, a Charpy notched impact strength according to ISO 179/1eA at +23°C of at least 15.0 kJ/m², preferably at least 25.0 kJ/m², a minimum value for the Charpy notched impact strength according to ISO 179/1eA at -20°C of at least 7.0 kJ/m², preferably at least 10.0 kJ/m² and a tensile modulus according to ISO 527-3 of at least 1200 MPa. It does however not disclose a blend of two different heterophasic propylene copolymers with specific amounts.

EP 2681277 A1 discloses a polyolefin composition comprising (a) 35 - 90 wt-% of a heterophasic polypropylene composition comprising (I) 10 - 50 wt-% of a first propylene homopolymer (PPH1) having an MFR230/2.16 of 30 - 80 g/10 min, (II) 20 - 65 wt-% of a second propylene homopolymer (PPH2) having an MFR2 of 100 - 250 g/10 min (230 °C, 2.16 kg), (ill) 5 - 30 wt-%, of a first xylene cold soluble fraction (XS1) having an intrinsic viscosity IV(XS1) of 2.0 - 3.0 dl/g, and (iv) 5 - 25 wt-%, of a second xylene cold soluble (XS2) fraction having an intrinsic viscosity IV(XS2) of 1.5 - 2.8 dl/g, with the proviso that IV(XS1 ) does not equal the IV(XS2), (b) 5 - 40 wt-% of an inorganic filler, and (c) 5 - 25 wt-%, based on the weight of the polyolefin composition, of an ethylene/1- butene elastomer.

It discloses mechanical properties solely for compounds with talcum and modifier. There is no disclosure on the mechanical properties of a blend made from two different heterophasic propylene copolymers.

EP 2947118 A1 covers compositions based on single-site-catalyst heterophasic propylene copolymers for automotive applications.

It discloses a PP composition comprising a heterophasic propylene copolymer (HECO) comprising

(a1) a matrix (M) being a propylene homopolymer (H-PP) or propylene copolymer (R-PP) and (a2) an elastomeric propylene copolymer (EC) dispersed in said matrix (M),and (b) a mineral filler (F), wherein said heterophasic propylene copolymer (HECO) has (iv) a melting temperature determined by differential scanning calorimetry (DSC) in the range of 140 to 155 °C, (v) a xylene cold soluble (XCS) content in the range of 20 to 35 wt.-%, (vi) a comonomer content of the xylene cold soluble (XCS) fraction in the range of 18 to 95 wt.-%, wherein further the weight ratio between heterophasic propylene copolymer (HECO) and the mineral filler (F) [(HECO)/(F)] is in the range of 2/1 to below

4/1. It does not disclose properties of blend consisting of two different heterophasic propylene copolymers, but only compounds with talcum, plastomers and HOPE.

EP 2611862 A1 covers a high-flow RTPO based on a single-site catalyst of earlier generation. The claimed HECO has (A) 35 to 75 wt-% of a fraction insoluble in p-xylene at 25°C (XCU) with an intrinsic viscosity of less than 1.1 dl/g, and a melting point of more than 150°C, and (B) 25 to 65 wt-% of a fraction soluble in p-xylene at 25°C (XCS) with an intrinsic viscosity of 2.0 to 5.0 dl/g, a content of ethylene and/or alpha olefin in the range of 40 to 70 wt.-%, and the absence of a melting point, in a DSC analysis in the range between 0 and 300°C, and the heterophasic polypropylene resin has a Charpy notched impact strength at -20°C of at least 12.5 kJ/m².

It discloses rather soft heterophasic propylene copolymers having a tensile modulus of 660 - 710 MPa with significantly higher XCS content than the heterophasic polypropylene compositions of the present invention.

So there is a need for heterophasic polypropylene compositions, which show high flowability and an improved impact/stiffness/toughness balance, especially in view of biaxial impact behaviour and which are in particular suitable for thin wall injection moulded applications. It is known that stiffness can be increased by introducing adequate nucleation agents and/or mineral filler components. These, however, will negatively affect the impact performance of the polymer, rendering it brittle, both in view of Charpy Impact behaviour and in biaxial impact behaviour as tested in the instrumented puncture test (I FT). It is further known, that polymers with high flowability tend to have higher amounts of low resp. lower molecular weight fractions, which are easily extractible, hence increasing the amounts of polymers extractable in xylene.

On the other hand, the amorphous rubbery phase, forming a dispersed phase within the heterophasic propylene copolymers, is essential for providing impact properties, but can due to its extractability in solvents negatively impact the amount of soluble fractions.

So, polymers having both high impact behaviour, well balanced impact/stiffness balance and low(-er) amounts of soluble fractions are sought.

Object of the invention Accordingly, it is an object of the present invention to provide such a composition. The above objects are achieved by a heterophasic polypropylene composition having an MFR230/2.16 of 15.0 - 150.0 g/10 min and comprising a) 70.0 - 95.0 wt.-% of a first heterophasic propylene copolymer and b) 5.0 - 30.0 wt.-% of a second heterophasic propylene copolymer being different from the first heterophasic propylene copolymer, characterised in that the first heterophasic propylene copolymer (a) comprises a1) 75.0 to 92.0 wt-% of a crystalline matrix corresponding to the crystalline fraction (CF) determined according to CRYSTEX QC method. ISO 6427-B. and a2) 8.0 to 25.0 wt.-% based on the total weight of the first heterophasic propylene copolymer of a soluble fraction (SF) corresponding to the soluble fraction as determined according to CRYSTEX QC method. ISO 6427-B. and a3) the soluble fraction has 15.0 to 45.0 wt.-% of comonomer (C2 of SF). determined according to CRYSTEX QC method. ISO 6427-B. and the second heterophasic propylene copolymer (b) comprises b1) 10.0 - 50.0 wt.-% of a fraction soluble in cold xylene (XCS) and wherein the heterophasic polypropylene composition comprises

8.0 to 24.0 wt.-% of a fraction soluble in cold xylene (XCS) and has a puncture energy of 15.0 to 100 J/mm when determined according to IS06603 on 2 mm plaques via an instrumented puncture test (I FT).

It was surprisingly found, that by combining two different heterophasic propylene copolymers it is possible to achieve a heterophasic polypropylene composition having higher flexural modulus than expected from the mere weighted average of the flexural moduli of the starting components.

It was further noticed, that also the impact behaviour (both for Charpy and biaxial puncture as determined in the Instrumented Puncture Test, IPT) of the heterophasic polypropylene composition was distinctly above the value expected from the mere weighted average of the impact values known from the initial heterophasic propylene copolymers alone. Furthermore, the heterophasic polypropylene composition of the present invention show an advantageous ratio of the puncture energy to the amount of the fraction soluble in cold xylene (XCS).

In one embodiment, the invention discloses articles comprising the heterophasic polypropylene composition. In a further embodiment, the invention relates to the use of the heterophasic polypropylene composition for producing moulded articles.

Detailed description: The term “heterophasic polypropylene composition” used herein denotes compositions comprising two different heterophasic propylene copolymers.

A heterophasic polypropylene copolymer 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.

The propylene homo- or copolymer is present in such an amount that it can form a continuous phase which can act as a matrix. Furthermore the terms “elastomeric propylene copolymer (EPC)”, “xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer”, “dispersed phase” and “ethylene propylene rubber” denote the same, i.e. are interchangeable.

Heterophasic polypropylene composition The heterophasic polypropylene composition of the present invention comprises two different heterophasic propylene copolymers, namely a first and a second heterophasic propylene copolymer, which differ from each other.

They may differ in at least one, preferably two or three features selected from the list of: catalysts employed, MFF¾, comonomer type and/or comonomer content, amount of the matrix in the heterophasic polypropylene composition and/or composition of the matrix as well as the amount of the dispersed phase within the heterophasic polypropylene composition and/or compositions of the dispersed phases. The heterophasic polypropylene composition comprises, preferably consists of a) 70.0 - 95.0 wt.-%, preferably 75.0 to 93.0 wt.-% or 80.0 to 92.0 wt.-%, of a first heterophasic propylene copolymer and b) 5.0 - 30.0 wt.-%, preferably 7.0 to 25 wt.-% or 8.0 - 20 wt.-% of a second heterophasic propylene copolymer.

The heterophasic polypropylene composition contains comonomers, preferably alpha- olefins selected from ethylene an C4 to C8 alpha olefins, preferably from ethylene, 1- butene or 1 -hexene. In a preferred embodiment, the heterophasic polypropylene composition comprises ethylene and 1 -butene as comonomer.

In an especially preferred embodiment, the heterophasic polypropylene composition comprises, only ethylene as the sole comonomer. Preferably, the heterophasic polypropylene composition consists of propylene and ethylene comonomer units.

The MFR2 of the heterophasic polypropylene composition may be in the range of 10 to 150 g/10min, preferably in the range of 15 to 100 g/10min, more preferably in the range of 50 to 90 g/10min.

The amount of the fraction soluble in cold xylene (XCS) of the heterophasic polypropylene composition may be in the range of 8.0 to below 24.0 wt.- %, preferably in the range of 9.0 to 21.0 wt.-%, more preferably in the range of 10.0 to 20.0 wt.-%.

The comonomer content of the fraction soluble in cold xylene, the C2(XCS), of the heterophasic polypropylene composition may be in the range of 15.0 to 45.0 wt.-%, preferably in the range of 17.5 to 35.0 wt.-%, more preferably in the range of 20.0 to 30.0 wt.-%.

The Intrinsic Viscosity of the fraction soluble in cold xylene, the IV(XCS), of the heterophasic polypropylene composition may be in the range of 1.8 to 5.0 dl/g, preferably in the range of 2.0 to 4.5 dl/g, more preferably in the range of 2.1 to 4.0 dl/g. First heterophasic propylene copolymer

The first heterophasic propylene copolymer forms the major part of the heterophasic polypropylene composition and is present in the heterophasic polypropylene composition in the ranges of 70.0 to 95.0 wt.-%, preferably in the range of 75.0 to 93.0 wt.-%, more preferably in the range of 80.0 to 92.0 wt.-%. The first heterophasic propylene copolymer contains comonomers, preferably alpha- olefins selected from ethylene an C4 to C8 alpha olefins, preferably from ethylene, 1- butene or 1 -hexene.

In a preferred embodiment, the first heterophasic polypropylene copolymer comprises ethylene and 1 -butene as comonomer.

In an especially preferred embodiment, the first heterophasic polypropylene copolymer comprises, only ethylene as the sole comonomer.

The total comonomer content, C2(total) of the first heterophasic polypropylene copolymer, may be in the range of 1.5 to 11.0 wt.-%, preferably in the range of 1.7 to 8.0 wt.-%, more preferably in the range of 1.8 to 6.5 wt.-%.

The MFR2 of the first heterophasic propylene copolymer may be in the range of 30.0 to 120.0 g/10min, preferably in the range of 35.0 to 110.0 g/10min, more preferably in the range of 40 to 100 g/10min.

The first heterophasic propylene copolymer comprises a1) a crystalline matrix corresponding to the crystalline fraction (CF) determined according to CRYSTEX QC method. ISO 6427-B, and being a propylene homo-or copolymer and a2) an amorphous fraction being an amorphous propylene ethylene elastomer dispersed therein and corresponding to the soluble fraction (SF) determined according to CRYSTEX QC method. ISO 6427-B.

The crystalline fraction may also comprise comonomers, especially ethylene. So, the amount of comonomer in the crystalline fraction, C2(CF), may be in the range of 0.0 to 2.5 wt.-%, preferably in the range of 0.3 to 2.0 wt.-%, more preferably in the range of 0.5 to 1.8 wt.-%.

The amount of the soluble fraction (SF) may be in the range of 8.0 to 24.0 wt.-%, preferably in the range of 9.0 to 21.0 wt.-%, more preferably in the range of 10.0 to 20.0 wt.-% based on the total weight of the first heterophasic propylene copolymer.

The soluble fraction comprises comonomer, in particular ethylene. So, the amount of comonomer in the soluble fraction, C2(SF), may be in the range of 15.0 to 45.0 wt.-%, preferably in the range of 17.5 to 35.0 wt.-%, more preferably in the range of 20.0 to 30.0 wt.-%. The Intrinsic Viscosity of the soluble fraction, IV(SF) may be in the range of 1.5 to 3.5 dl/g, preferably in the range of 1.8 to 3.3 dl/g, more preferably in the range of > 2.0 to 3.2 dl/g. The Intrinsic Viscosity of the crystalline fraction, IV(CF), may be in the range of 0.5 to 2.5 dl/g, preferably in the range of 0.8 to 2.3 dl/g, more preferably in the range of 1.0 to 2.2 dl/g.

The ratio between the Intrinsic Viscosity of the soluble fraction and the Intrinsic Viscosity of the crystalline fraction, IV(SF)/IV(CF), may be in the range of > 1.0 - 5.0, preferably in the range of 1.5 - 4.0, more preferably in the range 2.0 to 3.5. The amount of the fraction soluble in cold xylene (XCS) of the first heterophasic propylene copolymer may be in the range of 8.0 to < 25.0 wt.-%, preferably in the range of 9.0 to 21.0 wt.-%, more preferably in the range of 10.0 to 20.0 wt.-%.

The amount of comonomer of said fraction soluble in cold xylene, C2(XCS), may be in the range of 15.0 to 45.0 wt.-%, preferably in the range of 17.5 to 35.0 wt.-%, more preferably in the range of 20.0 to 30.0 wt.-%.

The Intrinsic Viscosity of said fraction soluble in cold xylene, IV(XCS), may be in the range of 1.8 to 3.5 dl/g, preferably in the range of 2.0 to 3.2 dl/g, more preferably in the range of 2.1 to 3.1 dl/g.

The melting temperature, Tm, of the first heterophasic propylene copolymer may be in the range of 145 to 164 °C, preferably in the range of 150 to 162 °C, more preferably in the range of 152 to 160 °C, the crystallisation temperature, Tc, may be in the range of > 110 to 135 °C, preferably in the range of 112 to 130 °C, more preferably in the range of 115 to 125 °C.

The crystalline matrix of the first heterophasic propylene copolymer may be present in the range of 78 to 95 wt.-%, preferably in the range of 80 to 93 wt.-%, more preferably in the range of 81 to 92 wt.-%, like in the range of 82 to 90 wt-%, based on the total weight of the heterophasic polypropylene composition. The elastomeric phase comprised in the first heterophasic polypropylene copolymer and dispersed in above mentioned matrix, may be present in the range of 5.0 to 22.0 wt.-%, preferably in the range of 7.0 to 20.0 wt-%, more preferably in the range of 8.0 to 19.0 wt.-%, like in the range of 10.0 to 18.0 wt.-%, based on the total weight of the first heterophasic polypropylene copolymer. Second heterophasic propylene copolymer

The second heterophasic propylene copolymer contains comonomers, preferably alpha- olefins selected from ethylene and C4 to C8 alpha olefins, preferably from ethylene, 1- butene or 1 -hexene. In a preferred embodiment, the second heterophasic polypropylene copolymer comprises ethylene and 1 -butene as comonomer.

In an especially preferred embodiment, the second heterophasic polypropylene copolymer comprises only ethylene as the sole comonomer. The amount of the second heterophasic propylene copolymer in the heterophasic polypropylene composition may be in the range of 5.0 to 30.0 wt.-%, preferably in the range of 7.0 to 25.0 wt.-%, more preferably in the range of 8.0 to 20.0 wt.-%, based on the total weight of the heterophasic polypropylene composition. The MFR2 of the second heterophasic propylene copolymer may be in the range of 0.5 to 200 g/10min, preferably in the range of 1.0 to 40 g/10min, more preferably in the range of 1.5 to 30 g/10min.

The second heterophasic propylene copolymer has a fraction soluble in cold xylene (XCS) in the range of 10.0 to 50.0 wt.-%, preferably in the range of 12.0 to 45.0 wt.-%, more preferably in the range of 13.0 to 40.0 wt.-%.

The comonomer content of the fraction soluble in cold xylene, C2(XCS), of the second heterophasic propylene copolymer may be in the range of 15.0 to 50.0 wt.-%, preferably in the range of 18.0 to 45 .0 wt.-%, more preferably in the range of 20.0 to 40.0 wt.-%.

The Intrinsic Viscosity of the fraction soluble in cold xylene, IV(XCS), may be in the range of 1.0 to 10.0 dl/g, preferably in the range of 1.2 to 9.0 dl/g, more preferably in the range of 1.4 to 8.0 dl/g.

The second heterophasic propylene copolymer is also produced in a multistage process, like in a loop-gas phase-process, as laid out for the first heterophasic propylene copolymer.

The second heterophasic propylene copolymer may be produced based on any known catalyst technology. The catalyst used during its polymerization may be the same or different to the catalyst used during the polymerization of the first heterophasic propylene copolymer. Preferably, the second heterophasic propylene copolymer is produced in the presence of a Ziegler-Natta catalyst. Polymerization process of the first and second heterophasic propylene copolymer: Both of the first and second heterophasic polypropylene copolymer of the present invention are typically and preferably made in a multistep process well known in the art. A preferred multistage process is a loop-gas phase-process, such as developed by Borealis A/S, Denmark (known as BORSTAR(R) technology) described e.g. in patent literature, such as in EP-A-0887379 or in WO 92/12182.

The heterophasic propylene copolymers of the invention preferably are produced by copolymerization of propylene, ethylene and optionally further comonomers as defined above and below, in an at least two, optionally three step process so as to form the heterophasic polypropylene composition. Preferably, propylene and ethylene are the only monomers used.

Ideally, the process of the invention employs two or more, preferably two main reactors, a first reactor operating in bulk, a first gas phase reactor and optionally a second gas phase reactor.

The process may also utilize a prepolymerization step, taking place in a separate reactor before the two or three main reactors.

The crystalline matrix of the first heterophasic propylene copolymer can be a propylene homo- or copolymer, ideally a propylene homopolymer.

The crystalline matrix is may present in the first heterophasic propylene copolymer in the range of 75.0 to 95.0 wt.-%, preferably in the range of 80.0 to 93.0 wt.-%, more preferably in the range of 83.0 to 90.0 wt.-%.

The MFR2 of the crystalline matrix of the first heterophasic propylene copolymer may be in the range of 80 to 200 g/10min, preferably in the range of 90 to 180 g/10min, more preferably in the range of 95 to 170 g/10min.

The first heterophasic polypropylene copolymer also comprises an elastomeric phase comprised in above mentioned matrix. The elastomeric phase is produced in a second polymerization step in the presence of the crystalline matrix and may be present in the range of 5.0 to 22.0 wt.-%, preferably in the range of 7.0 to 20.0 wt.-%, more preferably in the range of 10.0 to 17.0 wt.-%, based on the total weight of the first heterophasic polypropylene copolymer. The elastomeric is ideally an amorphous propylene ethylene elastomer.

Catalyst:

The first heterophasic propylene copolymer of the present invention is preferably polymerized in the presence of a single-site catalyst The catalyst used in the invention can be used in non-supported form or in solid form. The catalyst of the invention should however be used as a heterogeneous (solid) catalyst.

Generally, the quantity of catalyst will depend upon the nature of the catalyst, the selected reactor types and conditions and the properties desired for the polypropylene composition. The catalyst of the invention in solid form, preferably in solid particulate form, can be either supported on an external carrier material, like clay minerals, silica or alumina, or is free from an external carrier, however still being in solid form.

Preferably, the single site catalyst suitable for the present invention is represented by formula [ I ] as provided here below.

M is Ti, Zr or Hf.

Z is an oxygen atom or a sulfur atom, R³⁰, R³¹, R“and R³³may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, or an aryl group having a carbon number of 6 to 18. Q is a carbon atom, a silicon atom or a germanium atom.

Each of X¹ and X² is independently a halogen atom, an alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, an amino group substituted with an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, or a halogen-containing aryl group having a carbon number of 6 to 18.

R⁷and R¹⁷may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen- containing alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, or a halogen-containing aryl group having a carbon number of 6 to 18, and when either one of R⁷ and R¹⁷ is a hydrogen atom, the other is a substituent except for a hydrogen atom.

R⁸and R¹⁸may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, or a halogen- containing aryl group having a carbon number of 6 to 18.

R², R³, R⁴, R⁵, R⁶, R⁹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶and R¹⁹may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, a halogen-containing aryl group having a carbon number of 6 to 18.

A is a divalent hydrocarbon group having a carbon number of 3 to 12 and forming a ring together with Q to which it is bonded, and may contain an unsaturated bond. R¹⁰ is a substituent on A and is an alkyl group having a carbon number of 1 to 6, a halogen containing alkyl group having a carbon number of 1 to 6, a trialkylsilyl group- containing alkyl group having a carbon number of 1 to 6, a silyl group containing a hydrocarbon group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, or a halogen-containing aryl group having a carbon number of 6 to 18. Further, m represents an integer of 0 to 24, and when m is 2 or more, R¹⁰s may combine with each other to form a new ring structure).

In formula [ I ], specific examples of the alkyl group having a carbon number of 1 to 6 include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

Specific examples of the alkoxy group having a carbon number of 1 to 6 include a methoxy group, an ethoxy group, a n-propoxy group, an i-propoxy group, a n-butoxy group, a i-butoxy group, a tert-butoxy group, and a phenoxy group.

The aryl group having a carbon number of 6 to 18 may be substituted with a hydrocarbon group having a carbon number of 1 to 6, and specific examples of the aryl group include a phenyl group, a tolyl group, a dimethylphenyl group, an ethylphenyl group, a trimethylphenyl group, a tert-butylphenyl group, a di-tert-butylphenyl group, a biphenyl group, a 1 -naphthyl group, a 2-naphthyl group, an acenaphthyl group, a phenanthryl group, and an anthryl group.

In formula [I], the halogen atom includes a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom.

The amino group substituted with an alkyl group having a carbon number of 1 to 6 includes a dimethylamino group, a diethylamino group, a di-n-propylamino group, a di-i- propylamino group, a methylethylamino group, etc.

The halogen atom in the halogen-containing alkyl group having a carbon number of 1 to 6 includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The halogen-containing alkyl group having a carbon number of 1 to 6 is an alkyl group where a hydrogen atom on the skeleton of an alkyl group having a carbon number of 1 to 6 is replaced by a halogen atom.

Specific examples thereof include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, an iodomethyl group. In formula [I], the halogen-containing aryl group having a carbon number of 6 to 18 is specifically, for example.an aryl group in which a hydrogen atom of the above-described aryl group having a carbon number of 6 to 18 is replaced by a halogen atom, and specific examples thereof include 2-, 3- and 4-substituted fluorophenyl groups, 2-, 3- and 4- substituted chlorophenyl groups, 2-, 3- and 4-substituted bromophenyl groups, 2,4-, 2,5-,

2.6- and 3,5-substituted difluorophenyl groups, 2,4-, 2,5-, 2,6-, and 3,5-substituted dichlorophenyl groups, 2,4,6-, 2,3,4-, 2,4,5-, and 3,4,5-substituted trifluorophenyl groups,

2.4.6-, 2,3,4-, 2,4,5-, and 3,4,5-substituted trichlorophenyl groups, a pentafluorophenyl group, a pentachlorophenyl group, a 3,5-dimethyl-4-chlorophenyl group.

In formula [I], specific examples of the furyl group, the thienyl group, the fviryl group having a substituent, and the thienyl group having a substituent include a 2-furyl group, a 2-(5- methylfuryl) group, a 2-(5-ethylfuryl) group, a 2-(5-n-propylfuryl) group, a 2-(5-i-propylfuryl) group, a 2-(5-tert-butylfuryl) group, a 2-(5-trimethylsilylfuryl) group, a 2-(5-triethylsilylfuryl) group, a 2-(5-phenylfuryl) group, a 2-(5-tolylfuryl) group, a 2-(5-fluorophenylfuryl) group, a ,2-(5-chlorophenylfuryl) group, a 2-(4,5-dimethylfuryl) group, a 2-(3,5-dimethylfuryl) group, a 2-benzofuryl group, a 3-furyl group, a 3-(5-methylfuryl) group, a 3-(5-ethylfuryl) group, a 3-(5-n-propylfuryl) group, a 3-(5-i-propylfuryl) group, a 3-(5-tertbutylfuryl) group, a 3-(5- trimethylsilylfuryl) group, a 3-(5-triethylsilylfuryl) group, a 3-(5-phenylfuryl) group, a 3-(5- tolylfuryl) group, a 3-(5-fluorophenylfuryl) group, a 3-(5-chlorophenylfuryl) group, a 3-(4,5- dimethylfuryl) group, a 3-benzofuryl group, a 2-thienyl group, a 2-(5-methylthienyl) group, a 2-(5-ethylthienyl) group, a 2-(5-n-propylthienyl) group, a 2-(5-ipropylthienyl) group, a 2- (5-tert-butylthienyl) group, a 2-(5-trimethylsilylthienyl) group, a 2-(5-triethylsilylthienyl) group, a 2-(5-phenylthienyl) group, a 2-(5-tolylthienyl) group, a 2-(5-fluorophenylthienyl) group, a 2-(5-chlorophenylthienyl)group, a 2-(4,5-dimethylthienyl) group, a 2-(3,5- dimethylthienyl) group, a 2-benzothienyl group, a 3-thienyl group, a 3-(5- methylthienyl) group, a 3-(5-ethylthienyl) group, a 3-(5-n-propylthienyl) group, a 3-(5-i-propylthienyl) group, a 3-(5-tertbutylthienyl) group, a 3-(5-trimethylsilylthienyl) group, a 3-(5- triethylsilylthienyl) group, a 3-(5-phenylthienyl) group, a 3-(5-tolylthienyl) group, a 3-(5- fluorophenylthienyl) group, a 3-(5-chlorophenylthienyl) group, a 3-(4,5-dimethylthienyl) group, and a 3-benzothienyl group.

In formula [I], M is Ti, Zr or Hf, preferably Zr or Hf, more preferably Zr. Q is a carbon atom, a silicon atom or a germanium atom, preferably a silicon atom or a germanium atom. Each of X¹ and X² is independently a halogen atom, an alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, an amino group substituted with an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, or a halogen-containing aryl group having a carbon number of 6 to 18.

Among these, a halogen atom and a hydrocarbon group having a carbon number of 1 to 6 are preferred, and specifically, a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, an i-butyl group, and a phenyl group are more preferred.

R⁷ and R¹⁷ may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, or a halogen-containing aryl group having a carbon number of 6 to 18, and when either one of R⁷and R¹⁷is a hydrogen atom, the other is a substituent except for a hydrogen atom. R⁷and R¹⁷are preferably an alkyl group having a carbon number of 1 to 6 or an alkoxy group having a carbon number of 1 to 6, more preferably an alkyl group having a carbon number of 1 to 6. Among others, R⁷and R¹⁷are preferably a methyl group.

R⁸and R¹⁸ may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, or a halogen-containing aryl group having a carbon number of 6 to 18. R⁸ and R¹⁸ are preferably an alkyl group having a carbon number of 1 to 6. Among others, R⁸and R¹⁸are preferably a methyl group.

In preferred embodiment, the R⁷and R¹⁷and R⁸and R¹⁸ are identical and preferably selected from an alkyl group having a carbon number of 1 to 6. Especially preferred is that R⁷ and R¹⁷ and R⁸ and R¹⁸ are methyl groups.

R², R³, R⁴, R⁵, R⁸, R⁹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁸and R¹⁹ may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18. R⁹and R¹⁹, which are a substituent on an indenyl group, are preferably a hydrogen atom, an alkyl group having a carbon number of 1 to 6, or an alkoxy group having a carbon number of 1 to 6, more preferably a hydrogen atom.

R², R³, R⁴, R⁵, R^e, R¹², R¹³, R¹⁴, R¹⁵and R¹⁸, which are a substituent of a phenyl group on the 4-position of an indenyl group, are preferably a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, a trialkylsilyl group-containing alkyl group having a carbon number of 1 to 6, or an aryl group having a carbon number of 6 to 18. In addition, R², R⁶, R¹²and R^1sare preferably a hydrogen atom.

In formula [I], the substituent R³¹ is preferably a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, or an aryl group having a carbon number of 6 to 18, more preferably a hydrogen atom or an alkyl group having a carbon number of 1 to 6. The substituent R³⁰ is preferably a halogen atom, an alkyl group having a carbon number of 1 to 6, or an aryl group having a carbon number of 6 to 18, more preferably an alkyl group having a carbon number of 1 to 6 or an aryl group having a carbon number of 6 to

18. A is a divalent hydrocarbon group having a carbon number of 3 to 12 and forming a ring together with Q to which it is bonded, and may contain an unsaturated bond. A is preferably a divalent hydrocarbon group having a carbon number of 3 to 6 and forming a 4-to 7-membered ring, and A is more preferably a divalent hydrocarbon group having a carbon number of 3 or 4 and forming a 4- or 5-membered ring. R¹⁰ is a substituent on A and is an alkyl group having a carbon number of 1 to 6, a halogen-containing alkyl group having a carbon number of 1 to 6, an aryl group having a carbon number of 6 to 18, or a halogen-containing aryl group having a carbon number of 6 to 18. R¹⁰ is preferably an alkyl group having a carbon number of 1 to 6, more preferably a methyl group.

Further m represents an integer of 0 to 24, and when m is 2 or more, R¹⁰s may combine with each other to form a new ring structure, m is preferably an integer of 0 to 6, and m is more preferably 0. Specific examples of 5,6-dimethylindenyl skeleton when Q and A form a 4-membered ring (1) Dichlorosilacyclobutylenebis[2-(2-furyl)-4-phenyl-5,6-dimethyl-1-indenyl] zirconium

(2) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-phenyl-5,6-dimethyl-1-indenyl]- zirconium (3) Dichlorosilacyclobutylenebis[2-(4,5-dimethyl-2-furyl)-4-phenyl-5,6-dimethyl-1-indenyl] zirconium

(4) Dichlorosilacyclobutylenebis[2-(5-tert-butyl-2-furyl)-4-phenyl-5,6-dimethyl-1-indenyl] zirconium

(5) Dichlorosilacyclobutylenebis[2-(5-phenyl-2-furyl)-4-phenyl-5,6-dimethyl-1-indenyl] zirconium

(6) Dichlorosilacyclobutylenebis[2-(2-thienyl)-4-phenyl-5,6-dimethyl-1-indenyl] zirconium

(7) Dichlorosilacyclobutylenebis[2-(5-methyl-2-thienyl)-4-phenyl-5,6-dimethyl-1-indenyl] zirconium

(8) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(4-fluorophenyl)-5,6-dimethyl-1- indenyl] zirconium

(9) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(4-chlorophenyl)-5,6-dimethyl-1- indenyl] zirconium

(10) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(4-methylphenyl)-5,6-dimethyl-1- indenyl] zirconium (11) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(4-tert-butylphenyl)-5,6-dimethyl-

1-ind enyl] zirconium

(12) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(3,5-dimethylphenyl)-5, 6-dimethyl- 1 -indenyl] zirconium

(13) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(3,5-di-tert-butylphenyl)-5,6- dimethyl-1 -indenyl] zirconium

(14) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(1 -naphthyl)-5,6-dimethyl-1 - indenyl] zirconium

(15) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(2-naphthyl)-5,6-dimethyl-1 - indenyl] zirconium (16) Dichlorosilacyclobutylenebis[2-(5-methyl-2-furyl)-4-(4-biphenylyl)-5, 6-dimethyl- 1 - indenyl] zirconium

The component (B), i.e., a compound reacting with the component (A) to form an ion pair, or an ion-exchange layered silicate, includes an aluminium oxy compound, a boron compound, an ion-exchange layered silicate, etc. and is preferably an ion-exchange layered silicate. As the component (B), one of these compounds may be used alone, or two or more thereof may be mixed and used.

The ion-exchange layered silicate (hereinafter, sometimes simply referred to as "silicate") indicates a silicate compound having a crystal structure in which planes each constituted by an ionic bond, etc. are stacked one another in parallel by a bonding force, and contained ions are exchangeable.

In the present invention, the silicate preferably used as the component (B) is one belonging to a smectite group and specifically includes montmorillonite, sauconite, beidellite, nontronite, saponite, hectorite, stevensite, etc. Among these, in view of activity and molecular weight of the rubber component, montmorillonite is preferred.

Most natural silicates are produced as a main component of clay mineral, and impurities (e.g., quartz, cristobalite) other than the ion-exchange layered silicate are contained in many cases. Impurities may be contained in the smectite group silicate for use in the present invention.

Further details of component B are disclosed in EP3121187 A1, filed by Japan Polypropylene Corporation Tokyo.

The heterophasic polypropylene composition according to the invention may also be obtainable by an alternative catalyst system comprising by a single-site catalyst, more preferably being obtainable by a metallocene catalyst complex and cocatalysts.

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^'-tert- butylphenyl)-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-s- indacen-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-s- indacen-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’-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. Cocatalyst

To form an active catalytic species it is normally necessary to employ a cocatalyst as is well known in the art.

According to the present invention a cocatalyst system comprising a boron containing cocatalyst and an aluminoxane cocatalyst is used in combination with the above defined metallocene catalyst complex.

The aluminoxane cocatalyst can be one of formula (I):

where n is 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 AIR₃, AIR2Y and AI2R3Y₃ where R can be, for example, C₁- Cio-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 according to the invention as cocatalysts are not, owing to their mode of preparation, pure compounds, the molarity of aluminoxane solutions hereinafter is based on their aluminium content.

Also a boron containing cocatalyst is used in combination with the aluminoxane cocatalyst.

The catalyst complex ideally comprises a co-catalyst, certain boron containing cocatalysts are preferred. Especially preferred borates of use in the invention therefore comprise the trityl, i.e. triphenylcarbenium, ion. Thus the use of PhsCBiPhFs)* and analogues therefore are especially favoured.

The catalyst system of the invention is 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 man is aware of the procedures required to support a metallocene catalyst.

In a preferred embodiment, the catalyst system corresponds to the ICS3 of EP19177308.4. Producing the heterophasic polypropylene composition

For producing the heterophasic polypropylene composition, it is required to blend the first and second heterophasic propylene copolymer. This may be done by any compounding technology suitable, e.g. using a conventional compounding or blending apparatus, e.g. a Banbury mixer, a 2-roll rubber mill, Buss-co-kneader or a twin screw extruder may be used. The composition recovered from the extruder/mixer are usually in the form of pellets.

It is understood, that during said compound, usual additives, like stabilisers, antioxidants, nucleating agents, colorants, etc. are added.

These pellets are then preferably further processed, e.g. by injection moulding to generate articles and products of the inventive composition.

It is further understood, that polymers introduced as carriers of masterbatches or the like, may be present, even in case the claim is formulated in the closed wording, (“heterophasic polypropylene composition consisting of...”). Additives:

The heterophasic polypropylene composition according to the invention may further comprise conventional additives in an amount of up to 5.0 wt.-%, preferably in an amount 0.1 to 2.0 wt.-%, more preferably in an amount of 0.3 to 1.0 wt.-%. Examples of additives include, but are not limited to, stabilizers such as antioxidants (for example sterically hindered phenols, phosphites/phosphonites, sulphur containing antioxidants, alkyl radical scavengers, aromatic amines, hindered amine stabilizers, or blends thereof), metal deactivators (for example Irganox ® MD 1024), or UV stabilizers (for example hindered amine light stabilizers). Other typical additives are modifiers such as nucleating agents (for example sodium benzoate or sodium-2, 2'-methylene-bis(4,6-di-t- butylphenyl)phosphate), antistatic or antifogging agents (for example ethoxylated amines and amides or glycerol esters), acid scavengers (for example Ca-stearate) and blowing agentsfor foaming. Further modifiers are lubricants and resins (for example ionomer waxes, polyethylene- and ethylene copolymer waxes, Fischer Tropsch waxes, montan- based waxes, fluoro-based compounds, or paraffin waxes), as well as slip and antiblocking agents (for example erucamide, oleamide, talc, natural silica and synthetic silica or zeolites) and mixtures thereof.

Mechanical performance of the heterophasic polypropylene composition The heterophasic polypropylene composition has higher flexural modulus than expected from the mere weighted average of the flexural modulus of the starting components, namely the first and the second heterophasic propylene copolymer.

It was further noticed, that also the impact behaviour (both for Charpy and biaxial puncture resistance) of the heterophasic polypropylene composition was distinctly above the value, which would have been expected from the mere weighted average of the impact values known from the initial heterophasic propylene copolymers alone.

The flexural modulus of the heterophasic polypropylene composition of the present invention may be in the range of 900 to 2000 MPa, preferably in the range of 1000 to 1800 MPa, more preferably in the range of 1100 to 1600 MPa.

The Charpy notched impact strength at 23 °C, NIS 23°C, may be in the range of at least 6.0 kJ/m², preferably in the range of 6.0 to 60.0 kJ/m², more preferably in the range of 6.2 to 55.0 kJ/m². The Charpy notched impact strength at -20 °C, Charpy NIS -20°C may be in the range of 2.8 to 15.0 kJ/m², preferably in the range of 3.0 to 12.0, more preferably in the range of 3.1 to 9.0 kJ/m².

The puncture energy determined at +23 °C, IPT+23, may be in the range of 15.0 to 100 J/mm, preferably in the range of 17.5 to 50.0 J/mm, more preferably in the range of 20.0 to 40.0 J/mm.

The puncture energy determined at -20 °C, IPT-20 may be in the range of 8.0 to 35.0 J/mm, preferably in the range of 10.0 to 30.0 J/mm, more preferably in the range of 12.0 to 25.0 J/mm.

The heterophasic polypropylene composition of the present invention may also be described by their advantageous ratio of the puncture energy at +23 °C as well as at - 20 °C and the amount of the fraction soluble in cold xylene (XCS). The ratio of IPT+23/XCS may be in the range of 1.2 to 4.0 J/(mm*wt.-%), preferably in the range of 1.3 to 3.0 J/(mm*wt.-%), more preferably in the range of 1.4 to 2.5 J/(mm*wt.-%). The ratio of IPT-20/XCS may be in the range of 0.3 to 3.0 J/(mm*wt.-%), preferably in the range of 0.35 to 2.0 J/(mm*wt.-%), more preferably in the range of 0.40 to 1.5 J/(mm*wt.-

%).

In a special embodiment, the heterophasic polypropylene composition may have a flexural modulus in the range of 900 to 2000 MPa, preferably in the range of 1000 to 1800 MPa, more preferably in the range of 1100 to 1600 MPa and I. a puncture energy determined at +23 °C, IPT+23, may be in the range of 15.0 to 100 J/mm, preferably in the range of 17.5 to 50.0 J/mm, more preferably in the range of 20.0 to 40.0 J/mm and any one or more of ii. a ratio of IPT+23/XCS in the range of 1.2 to 4.0 J/(mm*wt.-%), preferably in the range of 1.3 to 3.0 J/(mm*wt.-%), more preferably in the range of 1.4 to 2.5 J/(mm*wt.-%) and/or ill. Charpy NIS 23°C in the range of at least 6.0 kJ/m², preferably in the range of 6.0 to 60.0 kJ/m², more preferably in the range of 6.2 to 55.0 kJ/m² and/or iv. Charpy NIS -20°C in the range of 2.8 to 15.0 kJ/m², preferably in the range of 3.0 to 12.0, more preferably in the range of 3.1 to 9.0 kJ/m². Alternatively, the heterophasic polypropylene composition may have i. a flexural modulus in the range of 900 to 2000 MPa, preferably in the range of 1000 to 1800 MPa, more preferably in the range of 1100 to 1600 MPa and ii. a puncture energy determined at +23 °C, IPT+23, may be in the range of 15.0 to 100 J/mm, preferably in the range of 17.5 to 50.0 J/mm, more preferably in the range of 20.0 to 40.0 J/mm and any one or more of iii. puncture energy determined at -20 °C, IPT-20 may be in the range of 8.0 to 35.0 J/mm, preferably in the range of 10.0 to 30.0 J/mm, more preferably in the range of 12.0 to 25.0 J/mm and/or iv. The ratio of IPT-20/XCS may be in the range of 0.3 to 3.0 J/(mm*wt.-%), preferably in the range of 0.35 to 2.0 J/(mm*wt.-%), more preferably in the range of 0.40 to 1 ,5J/(mm*wt.-%) and/or v. Charpy NIS -20°C in the range of 2.8 to 15.0 kJ/m², preferably in the range of 3.0 to 12.0, more preferably in the range of 3.1 to 9.0 kJ/m². Articles

The present invention also covers final articles, especially moulded articles comprising the heterophasic polypropylene composition of the present invention.

The articles may be injection moulded and may be used for packaging purposes or for application in the automotive industry. Preferably, said articles have a wall thickness of 0.1 to 3.0 mm, such as 0.5 to 2.5 mm, like 1.0 to 2.0 mm.

The present invention will now be described in further detail by the examples provided below:

Examples:

Measuring methods

Melt Flow Rate The melt flow rate (MFR2) is 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 MFR20f polypropylene is determined at a temperature of 230 °C and a load of 2.16 kg. Differential scanning calorimetry (DSC)

Differential scanning calorimetry (DSC) analysis, melting temperature (T_m) and melt enthalpy (H_m), crystallization temperature (T_c), and heat of crystallization (H_c, H_CR) are measured with a TA Instrument Q200 differential scanning calorimetry (DSC) on 5 to 7 mg samples. DSC is 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 (T_c) and heat of crystallization (H_c) are determined from the cooling step, while melting temperature (T_m) and melt enthalpy (Hm) are determined from the second heating step. Xylene Cold Soluble (XCS)

Xylene Cold Soluble fraction at room temperature (XCS, wt.-%) is determined at 25°C according to ISO 16152; 5^th edition; 2005-07-01.

Flexural Modulus The flexural modulus was determined in 3-point-bending at 23°C according to ISO 178 on 80x10x4 mm³ test bars injection moulded in line with EN ISO 1873-2.

The calculated flexural Modulus (FMcaic) was determined according to the formula (I)

FM_caic = W₁ * FM₁ + w₂ * FM₂ (I) wherein w1 and w2 denominate the relative weight of the first or second heterophasic propylene copolymer in the heterophasic polypropylene composition and FM1 and FM2 denominate the Flexural Modulus according to IS0178 of the first or second heterophasic propylene copolymer. Notched impact strength (NIS):

The Charpy notched impact strength (NIS) was measured according to ISO 179 1eA at +23°C or -20 °C, using injection moulded bar test specimens of 80x10x4 mm⁸ prepared in accordance with EN ISO 1873-2.

Puncture energy (IPT)

Puncture energy (IPT) is determined in the instrumented falling weight test according to 30 ISO 6603-2 using injection moulded plaques of 60x60x2 mm and a test speed of 4.4 m/s, clamped, lubricated striker with 20 mm diameter at test temperatures of +23 °C and (20 °C) respectively. The reported puncture energy results from an integral of the failure energy curve measured at (60x60x2 mm⁸).

Crystex analysis

Crystalline and soluble fractions method 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 the CRYSTEX QC, Polymer Char (Valencia, Spain).

A schematic representation of the CRYSTEX QC instrument is shown in Figure 1a. The crystalline and amorphous fractions are separated through temperature cycles of dissolution at 160°C, crystallization at 40°C and re-dissolution in a 1 ,2,4-trichlorobenzene (1,2,4-TCB) at 160°C as shown in Figure 1b. Quantification of SF and CF and determination of ethylene content (C2) are achieved by means of an infrared detector (IR4) and an online 2-capillary viscometer which is used for the determination of the intrinsic viscosity (IV). The IR4 detector is a multiple wavelength detector detecting IR absorbance at two different bands (CH3 and CH₂) 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 various concentration between 2 and 13mg/ml for each used EP copolymer used for calibration.

The amount of Soluble fraction (SF) and Crystalline Fraction (CF) are 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 ISQ16152. XS calibration is achieved by testing various EP copolymers with XS content in the range 2-31 Wt.-%. The intrinsic viscosity (IV) of the parent EP copolymer and its soluble and crystalline fractions are determined with a use of an online 2-capillary viscometer and are correlated to corresponding I Vs determined by standard method in decalin according to ISO 1628. Calibration is achieved with various EP PP copolymers with IV = 2-4 dL/g. A sample of the PP composition to be analyzed is weighed out in concentrations of

10mg/ml to 20mg/ml. After automated filling of the vial with 1,2,4-TCB containing 250 mg/I 2,6-tert-butyl-4-methylphenol (BHT) as antioxidant, the sample is dissolved at 160°C until complete dissolution is achieved, usually for 60 min, with constant stirring of 800rpm.

As shown in a Figure 1a and b, a defined volume of the sample solution is injected into the column filled with inert support where the crystallization of the sample and separation of the soluble fraction from the crystalline part is taking place. This process is repeated two times. During the first injection the whole sample is 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 are measured (wt.-% SF, wt.-% C2, IV).

EP means ethylene propylene copolymer.

PP means polypropylene.

Comonomer content (of the neat crystalline matrix) Quantitative infrared (IR) spectroscopy was used to quantify the ethylene content of the poly(ethylene-co-propene) copolymers through calibration to a primary method.

Calibration was facilitated through the use of a set of in-house non-commercial calibration standards of known ethylene contents determined by quantitative ¹³C solution-state nuclear magnetic resonance (NMR) spectroscopy. The calibration procedure was undertaken in the conventional manner well documented in the literature. The calibration set consisted of 38 calibration standards with ethylene contents ranging 0.2-75.0 wt% produced at either pilot or full scale under a variety of conditions. The calibration set was selected to reflect the typical variety of copolymers encountered by the final quantitative IR spectroscopy method. Quantitative IR spectra were recorded in the solid-state using a Broker Vertex 70 FTIR spectrometer. Spectra were recorded on 25x25 mm square films of 300 urn thickness prepared by compression moulding at 180 - 210°C and 4 - 6 mPa. For samples with very high ethylene contents (>50 mol%) 100 urn thick films were used. Standard transmission FTIR spectroscopy was employed using a spectral range of 5000-500 cm^"1, an aperture of 6 mm, a spectral resolution of 2 cm^'1, 16 background scans, 16 spectrum scans, an interferogram zero filling factor of 64 and Blackmann-Harris 3-term apodisation. Quantitative analysis was undertaken using the total area of the CH₂ rocking deformations at 730 and 720 cm ¹ (AQ) corresponding to ( CH₂)>2 structural units (integration method G, limits 762 and 694 cm ¹). The quantitative band was normalised to the area of the CH band at 4323 cm ¹ (AR) corresponding to CH structural units (integration method G, limits 4650, 4007 cm ¹). The ethylene content in units of weight percent was then predicted from the normalised absorption (AQ / AR) using a quadratic calibration curve. The calibration curve having previously been constructed by ordinary least squares (OLS) regression of the normalised absorptions and primary comonomer contents measured on the calibration set.

Poly(pmrolene-co-ethylene) - ethylene content for calibration using ¹³C NMR spectroscopy Quantitative ¹³C{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 for ¹H and ¹³C respectively. All spectra were recorded using a ¹³C optimised 10 mm extended temperature probehead at 125°C using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 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 (Singh, G., Kothari, A., Gupta, V., Polymer Testing 285 (2009), 475). 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 (Zhou, Z., Kuemmerle, R., Qiu, X, Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J.

Mag. Reson. 187 (2007) 225, Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6k) transients were acquired per spectra. Quantitative ^CfH} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. 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 (Cheng, H. N., Macromolecules 17 (1984), 1950) and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer fE = ( E / ( P + E ) The comonomer fraction was quantified using the method of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157) through integration 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 regio-defects when needed. Integral regions were slightly adjusted to increase applicability across the whole range of encountered comonomer contents. 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) )

Material description: Catalyst description for MC1

Preparation of the catalyst component for olefin polymerization:

(a) Acid and base treatment of ion-exchangeable layered silicate particles Benclay SL, whose major component is 2:1 -layered montmorillonite (smectite), was purchased from Mizusawa Industrial Chemicals, Ltd, and used for catalyst preparation. Benclay SL has the following properties:

Dp50 = 46.9 pm

Chemical composition [wt.-%]: Al 9.09, Si 32.8, Fe 2.63, Mg 2.12, Na 2.39, Al/Si 0.289 mol/mol

Acid Treatment

To a 2L-flask equipped with a reflux condenser and a mechanical agitation unit, 1300 g of distilled water and 168 g of sulfuric acid (96%) were introduced. The mixture was heated to 95 °C by an oil bath, and 200 g of Benday SL was added. Then the mixture was stirred at 95 °C for 840 min. The reaction was quenched by pouring the mixture into 2 L of pure water. The crude product was filtrated with a Buechner funnel connected with an aspirator and washed with 1 L of distilled water. Then the washed cake was re-dispersed in 902.1 g of distilled water. The pH of the dispersion was 1.7. Base treatment

The aqueous solution of LiOH was prepared by solving 3.54 g of lithium hydroxide mono hydrate into 42.11 g of distilled water. Then the aqueous LiOH solution was introduced to a dropping funnel and dripped in the dispersion obtained above at 40 °C. The mixture was stirred at 40 °C for 90 min. The pH of the dispersion was monitored through the reaction and stayed less than 8. The pH of the reaction mixture was 5.68. The crude product was filtrated with a Buechner funnel connected with an aspirator and washed 3 times with 2 L of distilled water each. The chemically treated ion-exchangeable layered silicate particles were obtained by drying the above cake at 110 °C overnight The yield was 140.8 g. Then the silicate particles were introduced into a 1 L-flask and heated to 200 °C under vacuum. After confirming that gas generation was stopped, the silicate particles were dried under vacuum at 200 °C for 2h. The catalyst component for olefin polymerization of the present innovation was obtained.

Preparation of olefin polvmerization catalvst

(b) Reaction with organic aluminum

To a 1000 ml flask, 10 g of the chemically treated ion exchangeable layered silicate particles obtained above (the catalyst component for olefin polymerization of the present invention) and 36 ml of heptane were introduced. To the flask, 64 ml of heptane solution of tri-n-octyl-alumiunum (TnOA), which includes 25 mmol of TnOA, was introduced. The mixture was stirred at ambient temperature for 1 h. The supernatant liquid was removed by decantation, and the solid material was washed twice with 900 ml of heptane. Then the total volume of reaction mixture was adjusted to 50 ml by adding heptane.

(c) prepolymerization

To the heptane slurry of the ion-exchangeable layered silicate particles treated with TnOA as described above, 31 ml of heptane solution of TnOA (12.2 mmol of TnOA) was added. To a 200 ml flask, 283 mg of (r)-dichlorosilacyclobutylene-bis [2- (5-methyl-2-furyl)-4-(4-t- butylphenyl)-5,6-dimethyl-1-indenyl] zirconium (300 μmol) and 30 ml of toluene were introduced. Then the obtained complex solution was introduced to the heptane slurry of the silicate particles. The mixture was stirred at 40 °C for 60 min.

Then the mixture was introduced into a 1 L-autoclave with a mechanical stirrer, whose internal atmosphere was fully replaced with nitrogen in advance of use. The autoclave was heated to 40 °C. After confirming the internal temperature was stable at 40 °C, propylene was introduced at the rate of 10 g/h at 40 °C. Propylene feeding was stopped after 2 h and the mixture was stirred at 40 °C for 1 h.

Then the residual propylene gas was purged out and reaction mixture was discharged into a glass flask. The supernatant solvent was discharged after settling enough. Then 8.3 ml of heptane solution of TiBAL (6 mmol) was added to the solid part. The mixture was dried under vacuum. The yield of solid catalyst for olefin polymerization (prepolymerized catalyst) was 35.83 g. Prepolymerization degree (the weight of prepolymer devided by the weight of solid catalyst) was 2.42.

Catalyst description for MC2 Catalyst synthesis

The metallocene (MC) used for MC2 was Antidimethylsilanediyl[2-methyl-4,8-di(3,5- dimethylphenyl)-I.5.6.7-tetrahydro-s-indacen-l-yl][-methyl-(3,5-dimethylphenyl)-5- methoxy-6-terf-butylinden-1 -yl] zirconium dichloride as disclosed in EP19177308.4 as I CSS.

Preparation of MAO-silica support

A steel reactor equipped with a mechanical stirrer and a filter net was flushed with nitrogen and the reactor temperature was set to 20 °C. Next silica grade DM-L-303 from AGC Si-Tech Co, pre-caldned at 600 °C (5.0 kg) was added from a feeding drum followed by careful pressuring and depressurising with nitrogen using manual valves. Then toluene (22 kg) was added. The mixture was stirred for 15 min. Next 30 wt% solution of MAO in toluene (9.0 kg) from Lanxess was added via feed line on the top of the reactor within 70 min. The reaction mixture was then heated up to 90°C and stirred at 90 °C for additional two hours. The slurry was allowed to settle and the mother liquor was filtered off. The catalyst was washed twice with toluene (22 kg) at 90°C, following by settling and filtration. The reactor was cooled off to 60°C and the solid was washed with heptane (22.2 kg). Finally MAO treated Si02 was dried at 60° under nitrogen flow for 2 hours and then for 5 hours under vacuum (-0.5 barg) with stirring. MAO treated support was collected as a free-flowing white powder found to contain 12.2% Al by weight

Catalyst preparation

30 wt% MAO in toluene (0.7 kg) was added into a steel nitrogen blanked reactor via a burette at 20 °C. Toluene (5.4 kg) was then added under stirring. The MC as cited above (93 g) was added from a metal cylinder followed by flushing with 1 kg toluene. The mixture was stirred for 60 minutes at 20 °C . Trityl tetrakis(pentafluorophenyl) borate (91 g) was then added from a metal cylinder followed by a flush with 1 kg of toluene. The mixture was stirred for 1 h at room temperature. The resulting solution was added to a a stirred cake of MAO-silica support prepared as described above over 1 hour. The cake was allowed to stay for 12 hours, foiled by drying under N2 flow at 60°C for 2h and additionally for 5 h under vacuum (-0.5 barg) under stirring. Dried catalyst was sampled in the form of pink free flowing powder containing 13.9% Al and 0.11% Zr.

Polymerization conditions PP1, PP2, PP3 and PP4:

All polymerizations were performed in a pilot-scale Borstar PP unit comprising a prepolymerization reactor, one liquid-phase loop reactor and three fluidized gas-phase reactors. The respective polymerization conditions are given in detail below.

Table 1 : Polymerization Data

Table 2 Polymerisation conditions, continued

MC1 is the metallocene based catalyst as described above.

MC2 is Anti-dimethylsilanediyl[2-methyl-4,8-di(3,5-dimethylphenyl)-1 ,5,6,7-tetrahydro-s- indacen-1-yl][2-methyl-4-(3,5-dimethylphenyl)-5-methoxy-6-teri-butylinden-1-yl] zirconium dichloride ... ZN1 is a Ziegler Natta catalyst comprising a non-phthalate based internal donor.

ZN2 is a Ziegler Natta catalyst comprising a phthalate based internal donor.

ZN3 is a Ziegler Natta catalyst comprising a non-phthalate based internal donor and a polymeric nucleating agent. It was produced as disclosed in EP2960279A1, Example 1, steps 1a and 1b.

Donor D is dicyclopentyl dimethoxy silan

Table 3: Polymer properties of the base polymer

Table 4: Polymer properties of the base polymers

Table 5: Physical characterisation of the base polymers

Table 6: Physical characterisation of the base polymers - continued

Table 7: Physical characterisation of the inventive compositions

Table 8 Physical characterisation of the inventive compositions (continued)

It can be derived from the results reported in tables above, that the inventive examples show higher stiffness then it would have been expected from the mere weighted average of the calculated flexural modulus of the starting components.

The inventive examples further have high impact behaviour and high puncture resistance both +23 °C as well at -20 °C. Furthermore, they have a high ratio of puncture resistance in relation to the amount of the fraction soluble in cold xylene (XCS).

Claims

1) Heterophasic polypropylene composition having an MFR230/2.16 of 15.0 - 150.0 g/10 min and comprising a) 70.0 - 95.0 wt.-% of a first heterophasic propylene copolymer and b) 5.0 - 30.0 wt.-% of a second heterophasic propylene copolymer being different from the first heterophasic propylene copolymer, characterised in that the first heterophasic propylene copolymer (a) is polymerized in the presence of a single-site catalyst and comprises a1) 75.0 to 92.0 wt.-% of a crystalline matrix corresponding to the crystalline fraction (CF) determined according to CRYSTEX QC method ISO 6427-B, and a2) 8.0 to 25.0 wt.-% based on the total weight of the first heterophasic propylene copolymer of a soluble fraction (SF) corresponding to the soluble fraction as determined according to CRYSTEX QC method, ISO 6427-B, and a3) the soluble fraction has 15.0 to 45.0 wt.-% of comonomer (C2 of SF), determined according to CRYSTEX QC method ISO 6427-B, and the second heterophasic propylene copolymer (b) comprises b1) 10.0 - 50.0 wt.-% of a fraction soluble in cold xylene (XCS) and wherein the heterophasic polypropylene composition comprises

8.0 to 24.0 wt.-% of a fraction soluble in cold xylene (XCS) and has a puncture energy of 15.0 to 100 J/mm when determined according to IS06603 on 2 mm plaques via an instrumented puncture test (IRT).

2) The heterophasic polypropylene composition according to claim 1, comprising a) 75.093.0 wt.-% or 80.0 to 92.0 wt.-% of the first heterophasic propylene copolymer and b) 7.0 to 25 wt.-% or 8.0 - 20 wt.-% of the second heterophasic propylene copolymer.

3) The heterophasic polypropylene composition according to any of the preceding claims, wherein the first heterophasic propylene copolymer comprises a1) 79.0 to 91.0 wt.-% or 80.0 to 90.0 wt.-% of a crystalline fraction and a2) 9.0 to 21.0 wt.-% or 10.0 - 20.0 wt-% of a soluble fraction. 4) The heterophasic polypropylene composition according to any of the preceding claims, wherein the second heterophasic propylene copolymer (b) comprises 12.0 to 45.0 or 13.0 to 40.0 wt.-% of a fraction soluble in cold xylene (XCS).

5) The heterophasic polypropylene composition according to any of the preceding claims, having a comonomer content of the fraction soluble in cold xylene (XCS) in the range of 15.0 to 50.0 wt.-%, like 18.0 to 45.0 wt.-% or 20.0 to 40.0 wt.-%. 6) The heterophasic polypropylene composition according to any of the preceding claims, wherein the first heterophasic propylene copolymer or the second heterophasic propylene copolymer independently from each other comprise ethylene as comonomer, preferably comprise ethylene as the sole comonomer. 7) The heterophasic polypropylene composition according to any of the preceding claims, wherein having an Intrinsic Viscosity of the xylene soluble fraction, IV(XS) in the range of 1.9 to 5.0 dl/g, like 2.0 to 4.5 dl/g or 2.1 to 4.0 dl/g.

8) The heterophasic polypropylene composition according to any of the preceding claims, wherein the first heterophasic propylene copolymer having an Intrinsic Viscosity of the soluble fraction, IV(SF), of 1.5 - 3.5 dl/g and/or a ratio of the IV(SF)/IV(CF) of 1.5 - 4.0, like 2.0 to 3.5.

9) The heterophasic polypropylene composition according to any of the preceding claims, wherein the first heterophasic propylene copolymer has a comonomer content of the crystalline fraction (C2 of CF) in the range of 0.0 to 2.5 wt.-% and/or an Intrinsic Viscosity of the crystalline fraction, IV(CF), in the range of 0.5 to 2.5 dl/g.

10) The heterophasic polypropylene composition according to any of the preceding claims, wherein the first heterophasic propylene copolymer has a comonomer content of the soluble fraction (C2 of SF) in the range of 17.5 to 35.0 or 20.0 to 30.0 wt.-% and/or an Intrinsic Viscosity of the soluble fraction, IV(SF), in the range of 1.8 to 3.3 or preferably more then 2.0 to 3.2 dl/g 11) The heterophasic polypropylene composition according to any of the preceding claims, wherein a flexural modulus according to ISO 178 of 900 to 2000 MPa, preferably 1000 to 1800 MPa, or 1100 to 1600 MPa, and an puncture energy at 23 °C (IPT+23) according to IS06603, determined on an Instrumented Puncture test (IPT) on 2 mm plaques of 17.5 to 50.0 J/mm or 20.0 - 40.0 J/mm.

12) The heterophasic polypropylene composition according to any of the preceding claims, wherein the ratio of the puncture energy at 23 °C (IPT+23) to the fraction soluble in cold xylene (XCS), (IPT+23 / XCS) in the range of 1.2 to 4.0 [J/(mm * wt.-%)], or 1.3 to 3.0 [J/(mm * wL-%)], like 1.4 to 2.5 [J/(mm * wL-%)].

13) Article, preferably injection moulded article, comprising the heterophasic polypropylene composition of any of the proceeding claims. 14) Use of the heterophasic polypropylene composition for producing articles, preferably for producing injection moulded articles.