WO2017041296A1

WO2017041296A1 - Polypropylene composition

Info

Publication number: WO2017041296A1
Application number: PCT/CN2015/089442
Authority: WO
Inventors: Weili QIANG; Shih Ping CHEN; Xin Zhou
Original assignee: Borouge Compounding Shanghai Co., Ltd.
Priority date: 2015-09-11
Filing date: 2015-09-11
Publication date: 2017-03-16
Also published as: CN107922692A; JP2018526498A; CN107922692B

Abstract

Polypropylene composition (C1) comprising a heterophasic propylene composition (HC) comprising a propylene homopolymer (HPP-1), a propylene homopolymer (HPP-2), an elastomeric propylene copolymer (PC-1), an elastomeric propylene copolymer (PC-2), an elastomeric ethylene copolymer (EC), and a filler (F).

Description

POLYPROPYLENE COMPOSITION

The present invention is directed to at a polypropylene composition, an automotive article comprising the polypropylene composition and the use of the polypropylene composition in an automotive article.

Polypropylene is the material of choice in many applications as it can be tailored to specific purposes needed. For instance heterophasic polypropylenes are widely used in the automobile industry (for instance in bumper applications) as they combine good stiffness with reasonable impact strength behaviour. Heterophasic polypropylenes contain a polypropylene matrix in which an amorphous phase is dispersed. The amorphous phase contains a copolymer rubber. Furthermore, the heterophasic polypropylene may contain crystalline polyethylene to some extent. Nowadays the automotive exterior parts become bigger and therefore excellent flowability is necessary during injection molding. Another advantage of high flow materials is a reduction of cycle-time. Furthermore, there is an increasing demand to reduce the fuel consumption and thus weight reduction is a burning topic in the automotive industry. Weight reduction can be achieved with lower wall thickness, or material density of parts. Lower wall thickness requires a higher stiffness. On the other hand the material has to have a high impact strength at normal temperature and low temperatures to resist damages.

Thus the object of the present invention is to provide a low-density material which exhibits good stiffness and impact strength paired with good processability, in particular in terms of high flowability.

The present invention is directed at a polypropylene composition (C1) comprising

(a) a heterophasic propylene composition (HC) comprising

(a1) a matrix (M) comprising a propylene homopolymer (HPP-1) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 100 g/10 min, and a propylene homopolymer (HPP-2) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 in the range of 30 to 90 g/10 min, and

(a2) an elastomeric propylene copolymer (PC-1) , an elastomeric propylene copolymer (PC-2) , and an elastomeric ethylene copolymer (EC) comprising units derived from ethylene and units derived from C₄-C₂₀ α-olefin, and

(b) a filler (F) .

The matrix (M) may additionally comprise a propylene homopolymer (HPP-3) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 25 g/10 min.

It is appreciated that the heterophasic propylene composition (HC) comprises

(a) the matrix (M) in an amount of at least 50 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(b) the elastomeric propylene copolymer (PC-1) , the elastomeric propylene copolymer (PC-2) and the elastomeric ethylene copolymer (EC) together in an amount of not more than 50 wt. ％, based on the weight of the heterophasic propylene composition (HC) .

Furthermore, it is appreciated that the heterophasic propylene composition (HC) comprises

(a) the propylene homopolymer (HPP-1) in an amount in the range of 25 to 60 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(b) the propylene homopolymer (HPP-2) in an amount in the range of 5 to 30 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(c) the propylene homopolymer (HPP-3) in an amount in the range of 0 to 20 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(d) the elastomeric propylene copolymer (PC-1) in an amount in the range of 2 to 15 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(e) the elastomeric propylene copolymer (PC-2) in an amount in the range of 2 to 15 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(f) the elastomeric ethylene copolymer (EC) in an amount in the range of 10 to 35 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

Furthermore, it is appreciated that the filler (F) is comprised in an amount of not more than 30 wt. -％, based on the weight of the polypropylene composition (C1) .

Furthermore, the present invention is directed at a polypropylene composition (C2) comprising

(a) a heterophasic propylene copolymer (HECO-1) comprising

(a1) a propylene homopolymer (HPP-1) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 100 g/10 min, and

(a2) an elastomeric propylene copolymer (PC-1) ,

(b) a heterophasic propylene copolymer (HECO-2) comprising

(b1) a propylene homopolymer (HPP-2) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 in the range of 30 to 90 g/10 min, and

(b2) an elastomeric propylene copolymer (PC-2) ,

(c) an elastomeric copolymer (EC) comprising units derived from ethylene and units derived from C₄-C₂₀ α-olefin.

The polypropylene composition (C2) may additionally comprise propylene homopolymer (HPP-3) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 25 g/10 min.

Preferably the polypropylene composition (C2) comprises

(a) the heterophasic propylene copolymer (HECO-1) in an amount of at least 25 wt. -％, based on the weight of the polypropylene composition (C2) ,

and/or

(b) the heterophasic propylene copolymer (HECO-2) in an amount in the range of 8 to 35 wt. -％, based on the weight of the polypropylene composition (C2) ,

and/or

(c) the elastomeric ethylene copolymer (EC) in an amount in the range of 8 to 30 wt. -％, based on the weight of the polypropylene composition (C2) ,

and/or

(d) the filler (F) in an amount in the range of to 1 to 30 wt. ％, based on the weight of the polypropylene composition (C2) ,

and/or

(e) the propylene homopolymer (HPP-3) in an amount in the range of 0 to 20 wt. -％, based on the weight of the polypropylene composition (C2) . Furthermore, a polypropylene composition (C2) is appreciated, wherein

(a) the comonomer content of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-1) is in the range of 30 to 60 mol ％, based on the weight of the heterophasic propylene copolymer (HECO-1) ,

and/or

(b) the comonomer content of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) is in the range of 30 to 60 mol ％, based on the weight of the heterophasic propylene copolymer (HECO-2) .

Furthermore, a polypropylene composition (C2) is appreciated wherein

(a) the comonomer content of the heterophasic propylene copolymer (HECO-1) is in the range of 5 to 20 mol％, based on the weight of the heterophasic propylene copolymer (HECO-1) ,

and/or

(b) the comonomer content of the heterophasic propylene copolymer (HECO-2) is in the range of 10 to 30 mol ％, based on the weight of the heterophasic propylene copolymer (HECO-2) .

Furthermore, a polypropylene composition (C2) is appreciated, wherein

(a) the intrinsic viscosity (IV) measured according to ISO 1268-1 (in decalin at 135 ℃) of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-1) is in the range of 1.5 to 3.0 dl/g,

and/or

(b) the intrinsic viscosity (IV) measured according to ISO 1268-1 (in decalin at 135 ℃) of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) is in the range of 1.5 to 3.2 dl/g.

Furthermore, a polypropylene composition (C1) or a polypropylene composition (C2) is appreciated, wherein the elastomeric ethylene copolymer (EC) has

(a) a melt flow rate MFR₂ (190 ℃, 2.16 kg) measured according to ISO 1133 in the range of 0.1 to 15 g/10 min,

and/or

(b) a density in the range of 830 to 890 kg/cm³.

Furthermore, a polypropylene composition (C1) or a polypropylene composition (C2) is appreciated having a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 in the range of 18 to 50 g/10 min.

In a third aspect the present invention is directed at an automotive article comprising the polypropylene composition (C1) and/or the polypropylene composition (C2) .

In a fourth aspect the present invention is directed at a use of the polypropylene composition (C1) and/or the polypropylene composition (C2) in an automotive article.

In the following the invention is described in more detail:

Polypropylene Composition (C1)

In a first aspect the present invention is directed at a polypropylene composition (C1) comprising

(a) a heterophasic propylene composition (HC) comprising

(a1) a matrix (M) comprising a propylene homopolymer (HPP-1) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 100 g/10 min, preferably of at least 120 g/10 min, more preferably of at least 140 g/10 min, even more preferably of at least 150 g/10 min, like in the range of 100 to 200 g/10 min, preferably in the range of 140 to 180 g/10 min, more preferably in the range of 150 to 170 g/10 min, and a propylene homopolymer (HPP-2) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 90 g/10 min, preferably of not more than 80 g/10 min, more preferably of not more than 75 g/10 min, even more preferably of not more than 70 g/10 min, yet even more preferably of not more than 65 g/10 min, like in the range of 30 to 90 g/10 min, preferably in the range of 30 to 80 g/10 min, more preferably in the range of 35 to 75 g/10 min, even more preferably in the range of 40 to 70 g/10 min, yet even more preferably in the range of 45 to 65 g/10 min, and

(a2) an elastomeric propylene copolymer (PC-1) , an elastomeric propylene copolymer (PC-2) and an elastomeric ethylene copolymer (EC) comprising units derived from ethylene and units derived from C₄-C₂₀ α-olefin, and

(b) a filler (F) .

Furthermore, the matrix (M) may additionally comprises a propylene homopolymer (HPP-3) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 25 g/10 min, preferably of not more than 20 g/10 min, more preferably of not more than 15 g/10 min, even more preferably of not more than 10 g/10 min, like in the range of 1 to 25 g/10 min, preferably in the range of 1 to 20 g/10 min, more preferably in the range of 3 to 15 g/10 min, even more preferably in the range of 5 to 10 g/10 min.

Preferably the matrix (M) consists of the propylene homopolymer (HPP-1) and the propylene homopolymer (HPP-2) ； or the propylene homopolymer (HPP-1) , the propylene homopolymer (HPP-2) and the propylene homopolymer (HPP-3) .

The polypropylene composition (C1) necessarily comprises a heterophasic propylene composition (HC) . It is appreciated that the heterophasic propylene composition (HC) is comprised in an amount of at least 50 wt. -％, preferably in an amount of at least 60 wt. -％, more preferably in an amount of not more 80 wt. -％, like in the range of 50 to 99 wt. ％, preferably in the range of 60 to 95 wt. -％, more preferably in the range of 70 to 95 wt. -％, even more preferably in the range of 85 to 95 wt. -％, based on the weight of the polypropylene composition (C1) .

The polypropylene composition (C1) necessarily comprises filler (F) . It is appreciated that the filler (F) is comprised in an amount of not more than 30 wt. -％, preferably in an amount of not more 20 wt. -％, more preferably in an amount of not more 14 wt. -％, like in the range of 1 to 30 wt. ％, preferably in the range of 5 to 20 wt. -％, more preferably in the range of 10 to 14 wt. -％, based on the weight of the polypropylene composition (C1) .

The heterophasic propylene composition (C3) and optionally polymeric carrier material (PCM) may be the only polymer component within the polypropylene composition (C1) , i.e. no other polymer components are present.

The polypropylene composition (C1) may consist of the heterophasic propylene composition (C3) , the filler (F) , and optionally additives (AD) .

It is a finding of the present invention that the density of the polypropylene composition (C1) can be reduced without negatively affecting the mechanical properties such as stiffness and impact resistance.

It is appreciated that the polypropylene composition (C1) has a density measured according to ISO 1183-187 of not more than 995 kg/cm³, preferably of not more than 990 kg/cm³, more preferably of not more than 985 kg/cm³, like in the range of 975 to 995 kg/cm³, preferably in the range of 975 to 990 kg/cm³, more preferably in the range of 975 to 985 kg/cm³.

Furthermore, it is appreciated that the polypropylene composition (C1) has a flexural modulus of at least 1400 MPa, preferably of at least 1500 MPa, more preferably of at least 1600 MPa, like in the range of 1400 to 1800 MPa, preferably in the range of 1500 to 1700 MPa, more preferably in the range of 1600 to 1700 MPa.

Furthermore, it is appreciated that the polypropylene composition (C1) has a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 15 g/10 min, preferably of at least 18 g/10 min, more preferably of at least 20 g/10 min, like in the range of 15 to 100 g/10 min, preferably in the range of 18 to 50 g/10 min, even more preferably in the range of 20 to 40 g/10 min.

All components used for the preparation of the instant composition, i.e. propylene composition (C1) , are known. Accordingly also their preparation is well known.

The polypropylene composition (C1) can be prepared by addingthe heterophasic propylene (HECO) , the filler (F) , optionally the additive (AD) , to an extruder and extruding the same.

Heterophasic Propylene Composition (HC)

The expression “heterophasic” indicates that at least one elastomeric copolymer is (finely) dispersed in a matrix. In other words the at least one elastomeric copolymer forms inclusions in the matrix. Thus the matrix contains (finely) dispersed inclusions being not part of the matrix and said inclusions contain the at least one elastomeric copolymer. The term "inclusion" shall preferably indicate that the matrix and the inclusion form different phases within the heterophasic propylene copolymer, said inclusions are for instance visible by high resolution microscopy, like electron microscopy or scanning force microscopy.

The matrix (M) of the heterophasic propylene composition (HC) comprises the propylene homopolymer (HPP-1) , the propylene homopolymer (HPP-2) and optionally the propylene homopolymer (HPP-3) , and probably forms a complex structure in the final composition. In other words the propylene homopolymer (HPP-1) , the propylene homopolymer (HPP-2) and optionally the propylene homopolymer (HPP-3) form a continuous phase, whereas the elastomeric propylene copolymer (PC-1) , the elastomeric propylene copolymer (PC-2) and the elastomeric ethylene copolymer (EC) form inclusions dispersed in this continuous phase.

Preferably the heterophasic propylene composition (HC) comprises the matrix (M) in an amount of at least 50 wt. -％, preferably in an amount of at least 55 wt. -％, more preferably in an amount of at least 60 wt. ％, like in the range of 50 to 80 wt. -％, preferably in the range of 55 to 75 wt. -％, more preferably in the range of 60 to 70 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

It is appreciated that the matrix (M) of the heterophasic propylene composition (HC) comprises the propylene homopolymer (HPP-1) in an amount of at least 25 wt. -％, preferably in an amount of at least 30 wt. -％, more preferably in an amount of at least 35 wt. -％, even more preferably in an amount of at least 40 wt. -％, like in the range of 25 to 60 wt. ％, preferably in the range of 30 to 55 wt. -％, more preferably in the range of 35 to 50 wt. -％, even more preferably in the range of 40 to 45 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

Furthermore, it is appreciated that the matrix (M) of the heterophasic propylene composition (HC) comprises the propylene homopolymer (HPP-2) in an amount of not more than 30 wt. -％, preferably in an amount of not more 25 wt. -％, more preferably in an amount of not more 20 wt. -％, like in the range of 5 to 30 wt. ％, preferably in the range of 6 to 25 wt. -％, more preferably in the range of 10 to 20 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

The propylene homopolymer (HPP-3) is not an essential compound of the polypropylene composition (C) . However, when the propylene homopolymer (HPP-3) is comprised in the matrix (M) of the heterophasic propylene composition (HC) it is appreciated that the propylene homopolymer (HPP-3) is present in an amount of not more 20 wt. -％, preferably in an amount of not more 15 wt. -％, like in the range of 0 to 20 wt. -％, preferably in the range of 5 to 20 wt. -％, more preferably in the range of 10 to 15 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

Preferably the heterophasic propylene composition (HC) comprises the elastomeric propylene copolymer (PC-1) , the elastomeric propylene copolymer (PC-2) and the elastomeric ethylene copolymer (EC) together in an amount of not more than 50 wt. -％, preferably in an amount of not more than 45 wt. -％, more preferably in an amount of not more than 40 wt. -％, like in the range of 20 to 50 wt. -％, preferably in the range of 25 to 45 wt. -％, more preferably in the range of 30 to 40 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

It is appreciated that the heterophasic propylene composition (HC) comprises the elastomeric propylene copolymer (PC-1) in an amount of at least 1 wt. -％, preferably in an amount of at least 2 wt. -％, more preferably in an amount of at least 3 wt. -％, even more preferably in an amount of at least 5 wt. -％, like in the range of 1 to 20 wt. ％, preferably in the range of 2 to 15 wt. ％, more preferably in the range of 5 to 15 wt. -％, even more preferably in the range of 5 to 10 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

Furthermore, it is appreciated that the heterophasic propylene composition (HC) comprises the elastomeric propylene copolymer (PC-2) in an amount of not more than 20 wt. -％, preferably in an amount of not more 15 wt. -％, more preferably in an amount of not more 10 wt. -％, like in the range of 1 to 20 wt. -％, preferably in the range of 2 to 15 wt. -％, more preferably in the range of 5 to 10 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

Furthermore, it is appreciated that the heterophasic propylene composition (HC) comprises the elastomeric ethylene copolymer (EC) in an amount of not more than 35 wt. -％, preferably in an amount of not more 30 wt. -％, more preferably in an amount of not more 25 wt. -％, like in the range of 10 to 35 wt. -％, preferably in the range of 15 to 30 wt. -％, more preferably in the range of 18 to 25 wt. -％, based on the weight of the heterophasic propylene composition (HC) .

The heterophasic propylene composition (HC) necessarily comprises both the propylene homopolymer (HPP-1) and the propylene homopolymer (HPP-2) . It is appreciated that the propylene homopolymer (HPP-1) and the propylene homopolymer (HPP-2) together fulfill inequation (Ia) , preferably inequation (Ib) , more preferably inequation (Ic) , even more preferably inequation (Id)

Co (HPP-1) /Co (HPP-2) ≥0.8 (Ia)

40≥Co (HPP-1) /Co (HPP-2) ≥0.8 (Ib)

20≥Co (HHP-1) /Co (HPP-2) ≥1.5 (Ic)

10≥Co (HPP-1) /Co (HPP-2) ≥2.0 (Id)

wherein

Co (HPP-1) is the amount of the propylene homopolymer (HPP-1) in wt. -％, based on the weight of the heterophasic propylene composition (HC) and Co (HPP-2) is the amount of the propylene homopolymer (HPP-2) in wt. -％, based on the weight of the heterophasic propylene composition (HC) .

As indicated above the propylene homopolymer (HPP-3) is an optional component of the heterophasic propylene composition (HC) . In case the propylene homopolymer (HPP-3) is present in the heterophasic propylene composition (HC) it is appreciated that the propylene homopolymer (HPP-1) and the propylene homopolymer (HPP-3) together fulfill inequation (IIa) , preferably inequation (IIb) , more preferably inequation (IIc) , even more preferably inequation (IId)

Co (HPP-1) /Co (HPP-3) ≥0.8 (IIa)

40≥Co (HPP-1) /Co (HPP-3) ≥0.8 (IIb)

20≥Co (HPP-1) /Co (HPP-3) ≥1.5 (IIc)

10≥Co (HPP-1) /Co (HPP-3) ≥2.0 (IId)

wherein

Co (HPP-1) is the amount of the propylene homopolymer (HPP-1) in wt. -％, based on the weight of the heterophasic propylene composition (HC) and Co (HPP-3) is the amount of the propylene homopolymer (HPP-3) in wt. -％, based on the weight of the heterophasic propylene composition (HC) .

Preferably the homopolymer (HPP-1) and the propylene homopolymer (HPP-2) of the heterophasic propylene composition (HC) fulfill together inequation (IIIa) , preferably inequation (IIIb) , more preferably inequation (IIIc) , even more preferably inequation (IIId)

MFR (HPP-1) –MFR (HPP-2) ≥50 (IIIa)

170≥MFR (HPP-1) –MFR (HPP-2) ≥50 (IIIb)

150≥MFR (HPP-1) –MFR (HPP-2) ≥70 (IIIc)

125≥MFR (HPP-1) –MFR (HPP-2) ≥90 (IIId)

wherein

MFR (HPP-1) is the melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of the propylene homopolymer (HPP-1) and MFR (HPP-2) is the melt flow rate MFR₂ (230℃, 2.16 kg) measured according to ISO 1133 of the propylene homopolymer (HPP-2) .

Preferably the homopolymer (HPP-1) and the propylene homopolymer (HPP-3) of the heterophasic propylene composition (HC) fulfill together inequation (IVa) , preferably inequation (IVb) , more preferably inequation (IVc) , even more preferably inequation (IVd)

MFR (HPP-1) –MFR (HPP-3) ≥75 (IVa)

190≥MFR (HPP-1) –MFR (HPP-3) ≥75 (IVb)

170≥MFR (HPP-1) –MFR (HPP-3) ≥100 (IVc)

165≥MFR (HPP-1) –MFR (HPP-3) ≥140 (IVd)

wherein

MFR (HPP-1) is the melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of the propylene homopolymer (HPP-1) and MFR (HPP-3) is the melt flow rate MFR₂ (230℃, 2.16 kg) measured according to ISO 1133 of the propylene homopolymer (HPP-3) .

It is appreciated that matrix (M) of the heterophasic propylene composition (HC) is multimodal in view of the molecular weight, in particular bimodal in case the propylene homopolymer (HPP-3) is not comprised or trimodal in case the propylene homopolymer (HPP-3) is comprised. The expression “multimodal” , “bimodal” or “trimodal” used throughout the present invention refers to the modality of the polymer, i.e. the form of its molecular weight distribution curve, which is the graph of the molecular weight fraction as a function of its molecular weight.

It is appreciated that the heterophasic propylene composition (HC) is nucleated, in particular α-nucleated.

Thus, it is appreciated that the heterophasic propylene composition (HC) comprises α-nucleating agent. Preferably the heterophasic propylene composition (HC) is free of β-nucleating agent.

The α-nucleating agent is preferably selected from the group consisting of

(i) salts of monocarboxylic acids and polycarboxylic acids, e.g. sodium benzoate or aluminum tert-butylbenzoate, and

(ii) dibenzylidenesorbitol (e.g. 1, 3 : 2, 4 dibenzylidenesorbitol) and C₁-C₈-alkyl-substituted dibenzylidenesorbitol derivatives, such as methyldibenzylidenesorbitol, ethyldibenzylidenesorbitol or dimethyldibenzylidenesorbitol (e.g. 1, 3 : 2, 4 di (methylbenzylidene) sorbitol) , or substituted nonitol-derivatives, such as 1, 2, 3, -trideoxy-4, 6: 5, 7-bis-O- [ (4-propylphenyl) methylene] -nonitol, and

(iii) salts of diesters of phosphoric acid, e.g. sodium 2, 2' -methylenebis (4, 6, -di-tert-butylphenyl) phosphate or aluminium-hydroxy-bis [2, 2' -methylene-bis (4, 6-di-t-butylphenyl) phosphate] , and

(iv) vinylcycloalkane polymer or vinylalkane polymer, and

(v) mixtures thereof.

Preferably the α-nucleating agent comprised in the heterophasic propylene composition (HC) is vinylcycloalkane polymer and/or vinylalkane polymer, more preferably vinylcycloalkane polymer, like vinylcyclohexane (VCH) polymer. Vinyl cyclohexane (VCH) polymer is particularly preferred as α-nucleating agent. It is appreciated that the amount of vinylcycloalkane, like vinylcyclohexane (VCH) , polymer and/or vinylalkane polymer, more preferably of vinylcyclohexane (VCH) polymer, in the heterophasic propylene composition (HC) , is not more than 500 ppm, preferably not more than 200 ppm, more preferably not more than 100 ppm, like in the range of 0.1 to 500 ppm, preferably in the range of 0.5 to 200 ppm, more preferably in the range of 1 to 100 ppm. Furthermore, it is appreciated that the vinylcycloalkane polymer and/or vinylalkane polymer is introduced into the heterophasic propylene composition (HC) by the BNT technology. With regard to the BNT-technology reference is made to the international applications WO 99/24478, WO 99/24479 and particularly WO 00/68315. According to this technology a catalyst system, preferably a Ziegler-Natta procatalyst, can be modified by polymerizing a vinyl compound in the presence of the catalyst system, comprising in particular the special Ziegler-Natta procatalyst, an external donor and a cocatalyst, which vinyl compound has the formula:

CH₂＝CH-CHR³R⁴

wherein R³ and R⁴together form a 5-or 6-membered saturated, unsaturated or aromatic ring or independently represent an alkyl group comprising 1 to 4 carbon atoms, and the modified catalyst is used for the preparation of the heterophasic propylene composition (HC) , or at least one of its components. The polymerized vinyl compound acts as an α-nucleating agent.

The weight ratio of vinyl compound to solid catalyst component in the modification step of the catalyst is preferably of up to 5 (5: 1) , more preferably up to 3 (3: 1) , like in the range of 0.5 (1: 2) to 2 (2: 1) .

Such nucleating agents are commercially available and are described, for example, in "Plastic Additives Handbook" , 5th edition, 2001 of Hans Zweifel (pages 967 to 990) .

The heterophasic propylene composition (HC) can be produced by blending the different components, i.e. the propylene homopolymer (HPP-1) , the propylene homopolymer (HPP-2) optionally the propylene homopolymer (HPP-3) , the elastomeric propylene copolymer (PC-1) , the elastomeric propylene copolymer (PC-2) and the elastomeric ethylene copolymer (EC) . Alternatively, the heterophasic propylene composition (HC) can be produced in a sequential step process, using reactors in serial configuration and operating at different reaction conditions. Alternatively the heterophasic propylene composition (HC) can be also obtainedby blending heterophasic propylene copolymer (HECO-1) , heterophasic propylene copolymer (HECO-2) , elastomeric ethylene copolymer (EC) and optionally propylene homopolymer (HPP-3) . For the definition of heterophasic propylene copolymer (HECO-1) and heterophasic propylene copolymer (HECO-2) reference is made to the propylene composition (C2) . In other words propylene homopolymer (HPP-1) and the elastomeric propylene copolymer (PC-1) can be introduced into the heterophasic propylene composition (HC) in form of heterophasic propylene copolymer (HECO-1) , whereas propylene homopolymer (HPP-2) and the elastomeric propylene copolymer (PC-2) can be introduced into the heterophasic propylene composition (HC) in form of heterophasic propylene copolymer (HECO-2) .

Propylene Homopolymer (HPP-1)

The propylene homopolymer (HPP-1) is a propylene homopolymer and provides sufficient stiffness and strength.

The expression “propylene homopolymer” relates to a polypropylene that consists substantially, i.e. of more than 99.7 mol ％, still more preferably of at least 99.8 mol％, of propylene units. In a preferred embodiment only propylene units are detectable in the propylene homopolymer.

It is appreciated that the propylene homopolymer (HPP-1) has a relatively high melt flow rate. It is appreciated that the propylene homopolymer (HPP-1) has a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 100 g/10 min, preferably at least 120 g/10 min, more preferably at least 140 g/10 min, even more preferably at least 150 g/10 min, like in the range of 100 to 200 g/10 min, preferably in the range of 140 to 180 g/10 min, even more preferably in the range of 150 to 170 g/10 min

Furthermore, it is appreciated that the propylene homopolymer (HPP-1) has a xylene cold soluble content (XCS) of below 5.0 wt. -％, preferably of below 3.0 wt. -％, even more preferably of below 2.5 wt. -％, like in the range of 0.5 to 5.0, preferably in the range of 1.0 to 3.0 wt. -％, even more preferably in the range of 1.0 to 2.5 wt. -％.

Elastomeric Propylene Copolymer (PC-1)

The elastomeric propylene copolymer (PC-1) comprises, preferably consists of, units derivable from (i) propylene and (ii) ethylene and/or at least another C₄ to C₂₀ α-olefin, like C₄ to C₁₀ α-olefin, more preferably units derivable from (i) propylene and (ii) ethylene and/or at least another α-olefin selected form the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene. The elastomeric propylene copolymer (PC-1) may additionally contain units derived from a conjugated diene, like butadiene, or a non-conjugated diene, however, it is preferred that the elastomeric copolymer consists of units derivable from (i) propylene and (ii) ethylene and/or C₄ to C₂₀ α-olefins only. Suitable non-conjugated dienes, if used, include straight-chain and branched-chain acyclic dienes, such as 1, 4-hexadiene, 1, 5-hexadiene, 1, 6-octadiene, 5-methyl-1, 4-hexadiene, 3, 7-dimethyl-1, 6-octadiene, 3, 7-dimethyl-1, 7-octadiene, and the mixed isomers of dihydromyrcene and dihydro-ocimene, and single ring alicyclic dienes such as 1, 4-cyclohexadiene, 1, 5-cyclooctadiene, 1, 5-cyclododecadiene, 4-vinyl cyclohexene, 1-allyl-4-isopropylidene cyclohexane, 3-allyl cyclopentene, 4-cyclohexene and 1-isopropenyl-4- (4-butenyl) cyclohexane. Multi-ring alicyclic fused and bridged ring dienes are also suitable including tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo (2, 2, 1) hepta-2, 5-diene, 2-methyl bicycloheptadiene, and alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes, such as 5-methylene-2-norbornene, 5-isopropylidene norbornene, 5- (4-cyclopentenyl) -2-norbornene； and 5-cyclohexylidene-2-norbornene. Preferred non-conjugated dienes are 5-ethylidene-2-norbornene, 1, 4-hexadiene and dicyclopentadiene.

Accordingly the elastomeric propylene copolymer (PC-1) comprises at least units derivable from propylene and units derivable from ethylene and/or a further α-olefin as defined in the previous paragraph. However it is in particular preferred that elastomeric propylene copolymer (PC-1) comprises units only derivable from propylene, units derivable from ethylene and optionally units derivable from a conjugated diene, like butadiene, or a non-conjugated diene as defined in the previous paragraph, like 1, 4-hexadiene. Thus, an ethylene propylene non-conjugated diene monomer polymer and/or an ethylene propylene polymer (EPR) are preferred as elastomeric propylene copolymer (PC-1) , the latter being most preferred.

It is appreciated that the elastomeric propylene copolymer (PC-1) comprises comonomer units, i.e. units comprised besides units derived from propylene, preferably units derived from ethylene, in an amount of at least 30 mol ％, preferably in an amount of at least 40 mol％, like in the range of 30 to 80 mol％, preferably in the range of 40 to 70 mol ％, more preferably in the range of 45 to 60 mol％, based on the weight of the elastomeric propylene copolymer (PC-1) .

Propylene Homopolymer (HPP-2)

The propylene homopolymer (HPP-2) is a propylene homopolymer and also contributes to a sufficient stiffness and strength.

It is appreciated that the propylene homopolymer (HPP-2) has a melt flow rate MFR₂ (230℃, 2.16 kg) measured according to ISO 1133 of not more than 90 g/10 min, preferably not more than 80 g/10 min, more preferably not more than 75 g/10 min, even more preferably not more than 70 g/10 min, yet even more preferably not more than 65 g/10 min, like in the range of 30 to 90 g/10 min, preferably in the range of 30 to 80 g/10 min, more preferably in the range of 35 to 75 g/10 min, even more preferably in the range of 40 to 70 g/10 min, yet even more preferably in the range of 45 to 65 g/10 min.

In other words it is appreciated that the propylene homopolymer (HPP-2) has a lower melt flow rate than the propylene homopolymer (HPP-1) .

Furthermore, it is appreciated that the propylene homopolymer (HPP-2) has a xylene cold soluble content (XCS) of below 5.0 wt. -％, preferably below 3.5 wt. -％, even more preferably below 3.0 wt. -％, like in the range of 0.5 to 5.0, preferably in the range of 1.0 to 3.5 wt. -％, even more preferably in the range of 1.0 to 2.5 wt. -％.

Elastomeric Propylene Copolymer (PC-2)

The elastomeric propylene copolymer (PC-2) comprises, preferably consists of, units derivable from (i) propylene and (ii) ethylene and/or at least another C₄ to C₂₀ α-olefin, like C₄ to C₁₀ α-olefin, more preferably units derivable from (i) propylene and (ii) ethylene and/or at least another α-olefin selected form the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene. The elastomeric propylene copolymer (PC-2) may additionally contain units derived from a conjugated diene, like butadiene, or a non-conjugated diene, however, it is preferred that the elastomeric copolymer consists of units derivable from (i) propylene and (ii) ethylene and/or C₄ to C₂₀ α-olefins only. Suitable non-conjugated dienes, if used, include straight-chain and branched-chain acyclic dienes, such as 1, 4-hexadiene, 1, 5-hexadiene, 1, 6-octadiene, 5-methyl-1, 4-hexadiene, 3, 7-dimethyl-1, 6-octadiene, 3, 7-dimethyl-1, 7-octadiene, and the mixed isomers of dihydromyrcene and dihydro-ocimene, and single ring alicyclic dienes such as 1, 4-cyclohexadiene, 1, 5-cyclooctadiene, 1, 5-cyclododecadiene, 4-vinyl cyclohexene, 1-allyl-4-isopropylidene cyclohexane, 3-allyl cyclopentene, 4-cyclohexene and 1-isopropenyl-4- (4-butenyl) cyclohexane. Multi-ring alicyclic fused and bridged ring dienes are also suitable including tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo (2, 2, 1) hepta-2, 5-diene, 2-methyl bicycloheptadiene, and alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes, such as 5-methylene-2-norbornene, 5-isopropylidene norbornene, 5- (4-cyclopentenyl) -2-norbornene； and 5-cyclohexylidene-2-norbornene. Preferred non-conjugated dienes are 5-ethylidene-2-norbornene, 1, 4-hexadiene and dicyclopentadiene.

Accordingly the elastomeric propylene copolymer (PC-2) comprises at least units derivable from propylene and units derivable from ethylene and/or a further α-olefin as defined in the previous paragraph. However it is in particular preferred that elastomeric propylene copolymer (PC-2) comprises units only derivable from propylene, units derivable from ethylene and optionally units derivable from a conjugated diene, like butadiene, or a non-conjugated diene as defined in the previous paragraph, like 1, 4-hexadiene. Thus, an ethylene propylene non-conjugated diene monomer polymer and/or an ethylene propylene polymer (EPR) are preferred as elastomeric propylene copolymer (PC-2) , the latter being most preferred.

It is appreciated that the elastomeric propylene copolymer (PC-2) comprises comonomer units, i.e. units comprised besides units derived from propylene, preferably units derived from ethylene, in an amount of at least 30 mol ％, preferably in an amount of at least 40 mol ％, like in the range of 30 to 80 mol ％, preferably in the range of 40 to 70 mol ％, more preferably in the range of 45 to 60 mol ％, based on the weight of the elastomeric propylene copolymer (PC-2.

It is appreciated that the elastomeric propylene copolymer (PC-1) and the elastomeric propylene copolymer (PC-2) are different to each other. However, the elastomeric propylene copolymer (PC-1) and the elastomeric propylene copolymer (PC-2) may also be identical to each other.

Propylene Homopolymer (HPP-3)

The propylene homopolymer (HPP-3) can be applied in addition to the propylene homopolymer (HPP-1) and the propylene homopolymer (HPP-2) to counteract a possible decrease in stiffness and strength caused by a lower level of filler in the composition (C1) .

It is appreciated that the propylene homopolymer (HPP-3) has a melt flow rate MFR₂ (230℃, 2.16 kg) measured according to ISO 1133 of not more than 25 g/10 min, preferably not more than 20 g/10 min, more preferably not more than 15 g/10 min, even more preferably not more than 10 g/10 min, like in the range of 1 to 25 g/10 min, preferably in the range of 1 to 20 g/10 min, more preferably in the range of 3 to 15 g/10 min, even more preferably in the range of 5 to 10 g/10 min.

Furthermore, it is appreciated that the propylene homopolymer (HPP-3) has a flexural modulus of at least 1800 MPa, preferably at least 1900 MPa, more preferably at least 2000 MPa, like in the range of 1800 to 2500 MPa, preferably in the range of 1900 to 2300 MPa, more preferably in the range of 2000 to 2200 MPa.

The propylene homopolymer (HPP-3) may have a lower melt flow rate than the propylene homopolymer (HPP-1) and a lower melt flow rate than the propylene homopolymer (HPP-2) .

Furthermore, it is appreciated that the propylene homopolymer (HPP-3) has a xylene cold soluble content (XCS) of below 5.0 wt. -％, preferably of below 3.5 wt. -％, even more preferably of below 3.0 wt. -％, like in the range of 0.5 to 5.0 wt. -％, preferably in the range of 1.0 to 3.5 wt. -％, even more preferably in the range of 1.0 to 2.5 wt. -％.

Elastomeric Ethylene Copolymer (EC)

The elastomeric ethylene copolymer (EC) is (chemically) different to the elastomeric propylene copolymer (PC-1) and the elastomeric propylene copolymer (PC-2) .

The elastomeric ethylene copolymer (EC) comprises, preferably consists of, units derivable from ethylene and units derivable from at least another C₄ to C₂₀ α-olefin, like C₄ to C₁₀ α-olefin, more preferably units derivable from ethylene and units derivable from at least another α-olefin selected form the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene, 1-butene and/or 1-octene being particularly preferred.

Accordingly the elastomeric ethylene copolymer (EC) comprises at least units derivable from ethylene and units derivable from a further α-olefin as defined in the previous paragraph. However it is in particular preferred that elastomeric ethylene copolymer (EC) comprises units only derivable from ethylene and units derivable from a further α-olefin like 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene. It is especially preferred that elastomeric ethylene copolymer (EC) comprises only units derivable from ethylene and units selected from 1-butene, 1 hexene and 1 octene. It is appreciated that the elastomeric ethylene copolymer (EC) comprises units only derivable from ethylene and units derivable from 1-octene, or only units derivable from ethylene and units derivable from 1-butene.

As indicated above the matrix (M) of the heterophasic propylene composition (HC) comprises (finely) dispersed inclusions of the elastomeric propylene copolymer (PC-1) , the elastomeric propylene copolymer (PC-2) and the elastomeric ethylene copolymer (EC) . The elastomeric ethylene copolymer (EC) may form on its part inclusions (finely dispersed) within in the elastomeric propylene copolymer (PC-1) and the elastomeric propylene copolymer (PC-2) .

It is appreciated that the elastomeric ethylene copolymer (EC) has a melt flow rate MFR₂ (190 ℃, 2.16 kg) measured according to ISO 1133 of not more than 15 g/10 min, preferably of not more than 10 g/10 min, more preferably of not more than 8.0 g/10 min, even more preferably of not more than 6.0 g/10 min, like in the range of 0.1 to 15 g/10 min, preferably in the range of 0.5 to 10 g/10 min, more preferably in the range of 1.0 to 8.0 g/10 min even more preferably in the range of 1.0 to 6.0 g/10 min.

It is appreciated that the elastomeric ethylene copolymer (EC) has a density measured according to ISO 1183-187 of not more than 890 kg/cm³, preferably of not more than 0.880 kg/cm³, more preferably of not more than 0.875 kg/cm³, like in the range of 830 to 890 kg/cm³, preferably in the range of 840 to 0.880 kg/cm³, more preferably in the range of 850 to 875 kg/cm³, even more preferably in the range of 860 to 875 kg/cm³.

It is appreciated that the ethylene content of the elastomeric ethylene copolymer (EC) is at least 70 mol ％, preferably is at least 80 mol ％, like in the range of 70 to 98 mol ％, preferably in the range of 80 to 95 mol ％, more preferably 82 to 92 mol％.

Filler (F)

As a further requirement the polypropylene composition (C1) requires the presence of filler (F) . Thus, the filler (F) is not regarded as being encompassed by the additives (AD) defined in more detail below.

Preferably filler (F) is a mineral filler. It is appreciated that the filler (F) is a phyllosilicate, mica or wollastonite. Even more preferred the filler (F) is selected from the group consisting of mica, wollastonite, kaolinite, smectite, montmorillonite and talc. The most preferred the filler (F) is talc.

It is appreciated that the filler (F) has median particle size (D₅₀) in the range of 0.8 to 20 μm and a top cut particle size (D₉₅) in the range of 1.0 to 40 μm, preferably a median particle size (D₅₀) in the range of 1.0 to 10 μm and top cut particle size (D₉₅) in the range of 2.0 to 30 μm, more preferably a median particle size (D₅₀) in the range of 1.2 to 5.0 μm and top cut particle size (D₉₅) of 3.0 -10 μm.

Typically the filler (F) has a surface area measured according to the commonly known BET method with N₂ gas as analysis adsorptive of less than 20 m²/g, more preferably of less than 15 m²/g, like in the range of 1 to 20 m²/g, preferably in the range of 5 to 15 m²/g.

Fillers (F) fulfilling these requirements are preferably anisotropic mineral fillers (F) , like talc, mica and wollastonite. Especially preferred is talc.

The the filler (F) is state of the art and a commercially available product.

Additives (AD)

In addition to the heterophasic propylene composition (HC) , and the filler (F) the polypropylene composition (C1) may include additives (AD) . Typical additives are acid scavengers, antioxidants, colorants, light stabilisers, plasticizers, slip agents, anti-scratch agents, dispersing agents, processing aids, lubricants, pigments, antistatic agent, and the like. As indicated above the filler (F) is not regarded as an additive.

Such additives are commercially available and for example described in “Plastic Additives Handbook” , 6^th edition 2009 of Hans Zweifel (pages 1141 to 1190) .

Furthermore, the term “additives (AD) ” according to the present invention also includes carrier materials, in particular polymeric carrier materials (PCM) , especially polypropylene carrier material.

Preferably the polypropylene composition (C1) comprises 0.1 to 20 wt. -％, preferably 0.5 to 15 wt. -％, more preferably 0.5 to 10 wt. -％, even more preferably 0.5 to 5.0 wt. -％of the additives (AD) , based on the weight of the polypropylene composition (C1) .

In a preferred embodiment the polypropylene composition (C1) comprises antioxidant, acid scavenger, anti-scratch agent, mould-release agent, lubricant, and UV stabiliser.

The Polymeric Carrier Material (PCM)

Preferably the polypropylene composition (C1) does not comprise (a) further polymer (s) different to the polymer (s) comprised in the polymers polypropylene composition (C1) mentioned above, i.e. the propylene homopolymer (HPP-1) , thepropylene homopolymer (HPP-2) , the elastomeric propylene copolymer (PC-1) , the elastomeric propylene copolymer (PC-2) , the elastomeric ethylene copolymer (EC) and optionally the propylene homopolymer (HPP-3) , in an amount exceeding 10 wt. -％, preferably in an amount exceeding 5 wt. -％, more preferably in an amount exceeding 3 wt. -％, based on the weight of the polypropylene composition (C1) . If an additional polymer is present, such a polymer is typically a polymeric carrier material (PCM) for additives.

It is appreciated that the polypropylene composition (C1) comprises polymeric carrier material (PCM) in an amount of not more than 10 wt. -％, preferably in an amount of not more than 5.0 wt. -％, more preferably in an amount of not more than 3.0 wt. -％, like in the range of 0 to 10.0 wt. -％, preferably in the range of 0.3 to 5.0 wt. -％, even more preferably in the range of 0.5 to 3.0 wt. -％, based on the weight of the polypropylene composition (C1) .

The polymeric carrier material (PCM) is a carrier polymer for the other additives to ensure a uniform distribution in the polypropylene composition (C1) . The polymeric carrier material (PCM) is not limited to a particular polymer. The polymeric carrier material (PCM) may be ethylene homopolymer， ethylene copolymer obtained from ethylene and α-olefin comonomer such as C₃ to C₈ α-olefin comonomer, propylene homopolymer and/or propylene copolymer obtained from propylene and α-olefin comonomer such as ethylene and/or C₄ to C₈ α-olefin comonomer.

Polypropylene Composition (C2)

In a second aspect the present invention is directed at Polypropylene composition (C2) comprising

(a) a heterophasic propylene copolymer (HECO-1) comprising

(a1) a propylene homopolymer (HPP-1) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 100 g/10 min, preferably at least 120 g/10 min, more preferably at least 140 g/10 min, even more preferably at least 150 g/10 min, like in the range of 100 to 200 g/10 min, preferably in the range of 140 to 180 g/10 min, even more preferably in the range of 150 to 170 g/10 min, and

(a2) an elastomeric propylene copolymer (PC-1) ,

(b) a heterophasic propylene copolymer (HECO-2) comprising

(b1) a propylene homopolymer (HPP-2) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 90 g/10 min, preferably of not more than 80 g/10 min, more preferably of not more than 75 g/10 min, even more preferably of not more than 70 g/10 min, yet even more preferably of not more than 65 g/10 min, like in the range of 30 to 90 g/10 min, preferably in the range of 30 to 80 g/10 min, more preferably in the range of 35 to 75 g/10 min, even more preferably in the range of 40 to 70 g/10 min, yet even more preferably in the range of 45 to 65 g/10 min and

(b2) an elastomeric propylene copolymer (PC-2) ,

The polypropylene composition (C2) may additionally comprise apropylene homopolymer (HPP-3) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 25 g/10 min, preferably of not more than 20 g/10 min, more preferably of not more than 15 g/10 min, even more preferably of not more than 10 g/10 min, like in the range of 1 to 25 g/10 min, preferably in the range of 1 to 20 g/10 min, more preferably in the range of 3 to 15 g/10 min, even more preferably in the range of 5 to 10 g/10 min.

It is appreciated that the polypropylene composition (C2) comprises the heterophasic propylene copolymer (HECO-1) in an amount of at least 25 wt. -％, preferably in an amount of at least 30 wt. -％, more preferably in an amount of at least 35 wt. -％, even more preferably in an amount of at least 40 wt. -％, like in the range of 25 to 70 wt. ％, preferably in the range of 30 to 60 wt. -％, more preferably in the range of 35 to 55 wt. -％, even more preferably in the range of 41 to 50 wt. -％, based on the weight of the polypropylene composition (C2) .

It is appreciated that the heterophasic propylene copolymer (HECO-1) comprises the propylene homopolymer (HPP-1) in an amount of at least 55 wt. -％, preferably in an amount of at least 65 wt. -％, more preferably in an amount of at least 80 wt. -％, like in the range of 55 to 95 wt. ％, preferably in the range of 65 to 90 wt. -％, more preferably in the range of 80 to 90 wt. -％, based on the weight of the heterophasic propylene copolymer (HECO-1) .

Furthermore, it is appreciated that the heterophasic propylene copolymer (HECO-1) comprises the elastomeric propylene copolymer (PC-1) in an amount of not more than 45 wt. -％, preferably in an amount of not more 35 wt. -％, more preferably in an amount of not more 20 wt. -％, like in the range of 5 to 45 wt. -％, preferably in the range of 10 to 35 wt. -％, more preferably in the range of 10 to 20 wt. -％, based on the weight of the heterophasic propylene copolymer (HECO-1) .

It is appreciated that the polypropylene composition (C2) comprises the heterophasic propylene copolymer (HECO-2) in an amount of not more than 35 wt. -％, preferably in an amount of not more than 25 wt. -％, more preferably in an amount of not more than 19 wt. -％, like in the range of 8 to 35 wt. ％, preferably in the range of 10 to 25 wt. -％, more preferably in the range of 13 to 19 wt. -％, based on the weight of the polypropylene composition (C2) .

It is appreciated that the heterophasic propylene copolymer (HECO-2) comprises the propylene homopolymer (HPP-2) in an amount of at least 35 wt. -％, preferably in an amount of at least 45 wt. -％, more preferably in an amount of at least 55 wt. -％, even more preferably in an amount of at least 60 wt. -％, like in the range of 35 to 95 wt. ％, preferably in the range of 45 to 85 wt. -％, more preferably in the range of 55 to 75 wt. -％, based on the weight of the heterophasic propylene copolymer (HECO-2) .

Furthermore, it is appreciated that the heterophasic propylene copolymer (HECO-2) comprises the elastomeric propylene copolymer (PC-2) in an amount of not more than 65 wt. -％, preferably in an amount of not more than 55 wt. -％, more preferably in an amount of not more than 45 wt. -％, even more preferably in an amount of not more than 40 wt. -％, like in the range of 5 to 65 wt. -％, preferably in the range of 15 to 55 wt. -％, more preferably in the range of 10 to 45 wt. -％, even more preferably in the range of 25 to 45 wt. -％, based on the weight of the heterophasic propylene copolymer (HECO-2) .

Furthermore, it is appreciated that the polypropylene composition (C2) comprises the elastomeric ethylene copolymer (EC) in an amount of not more than 30 wt. -％, preferably in an amount of not more 25 wt. -％, like in the range of 8 to 30 wt. -％, preferably in the range of 10 to 30 wt. -％, more preferably in the range of 15 to 25 wt. -％, based on the weight of the polypropylene composition (C2) .

Furthermore, it is appreciated that the polypropylene composition (C2) comprises the filler (F) in an amount of not more than 30 wt. -％, preferably in an amount of not more 20 wt. -％, more preferably in an amount of not more than 14 wt. -％, like in the range of 1 to 30 wt. -％, preferably in the range of 5 to 20 wt. -％, even more preferably in the range of 10 to 14 wt. -％, based on the weight of the polypropylene composition (C2) .

The propylene homopolymer (HPP-3) is not an essential compound of the polypropylene composition (C2) . However, when the propylene homopolymer (HPP-3) is comprised in the polypropylene composition (C2) it is appreciated that the propylene homopolymer (HPP-3) is present in an amount of not more than 25 wt. -％, preferably in an amount of not more 20 wt. -％, more preferably in an amount of not more 15 wt. -％, like in the range of 0 to 20 wt. -％, preferably in the range of 1 to 20 wt. -％, preferably in the range of 5 to 15 wt. -％, based on the weight of the polypropylene composition (C2) .

The polypropylene composition (C2) may comprise additives (AD) in an amount in the range of 0.1 to 20 wt. -％, preferably in the range of 0.5 to 15 wt. -％, more preferably in the range of 0.5 to 10 wt. -％, even more preferably in the range of 0.5 to 5.0 wt. -％, based on the weight of the polypropylene composition (C2) .

The heterophasic propylene copolymer (HECO-1) , the heterophasic propylene copolymer (HECO-2) , the elastomeric ethylene copolymer (EC) , optionally the propylene homopolymer (HPP-3) and optionally polymeric carrier material (PCM) may be the only polymer components within the polypropylene composition (C2) , i.e. no other polymer components are present.

The polypropylene composition (C2) may consist of the heterophasic propylene copolymer (HECO-1) , the heterophasic propylene copolymer (HECO-2) , the elastomeric ethylene copolymer (EC) , the filler (F) , optionally the propylene homopolymer (HPP-3) , and optionally additives (AD) .

Preferably the homopolymer (HPP-1) and the propylene homopolymer (HPP-2) of the polypropylene composition (C2) fulfill together inequation (IIIa’ ) , preferably inequation (IIIb’ ) , more preferably inequation (IIIc’ ) , even more preferably inequation (IIId’ )

MFR (HPP-1) –MFR (HPP-2) ≥50 (IIIa’ )

170≥MFR (HPP-1) –MFR (HPP-2) ≥50 (IIIb’ )

150≥MFR (HPP-1) –MFR (HPP-2) ≥70 (IIIc’ )

125≥MFR (HPP-1) –MFR (HPP-2) ≥90 (IIId’ )

wherein

Preferably the homopolymer (HPP-1) and the propylene homopolymer (HPP-2) of the polypropylene composition (C2) fulfill together inequation (IVa' ) , preferably inequation (IVb’ ) , more preferably inequation (IVc’ ) , even more preferably inequation (IVd’ )

MFR (HPP-1) –MFR (HPP-3) ≥75 (IVa’ )

190≥MFR (HPP-1) –MFR (HPP-3) ≥75 (IVb’ )

170≥MFR (HPP-1) –MFR (HPP-3) ≥100 (IVc’ )

165≥MFR (HPP-1) –MFR (HPP-3) ≥140 (IVd’ )

wherein

It is appreciated that the polypropylene composition (C2) has a flexural modulus of at least 1400 MPa, preferably of at least 1500 MPa, more preferably of at least 1600 MPa, like in the range of 1400 to 1800 MPa, preferably in the range of 1500 to 1700 MPa, more preferably in the range of 1600 to 1700 MPa.

Furthermore, it is appreciated that the polypropylene composition (C2) has a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 15 g/10 min, preferably of at least 18 g/10 min, more preferably of at least 20 g/10 min, like in the range of 15 to 100 g/10 min, preferably in the range of 18 to 50 g/10 min, more preferably in the range of 20 to 40 g/10 min.

It is a finding of the present invention that the density of the polypropylene composition (C2) can be reduced without negatively affecting the mechanical properties such as stiffness and impact resistance. Thus, it is appreciated that the polypropylene composition (C2) has a density measured according to ISO 1183-187 of not more than 995 kg/cm³, preferably of not more than 990 kg/cm³, like in the range of 975 to 995 kg/cm³, preferably in the range of 975 to 990 kg/cm³, more preferably in the range of 975 to 985 kg/cm³.

All components used for the preparation of the instant composition, i.e. propylene composition (C2) , are known. Accordingly also their preparation is well known.

The polypropylene composition (C2) can be prepared by addingthe heterophasic propylene (HECO-1) , the heterophasic propylene (HECO-1) , the elastomeric ethylene copolymer (EC) , the filler (F) , optionally the propylene homopolymer (HPP-3) and optionally the additive (AD) , to an extruder and extruding the same.

The Heterophasic Propylene Copolymer (HECO-1)

As indicated above the expression “heterophasic” indicates that at least one elastomeric copolymer is (finely) dispersed in a matrix. The heterophasic composition (HECO-1) preferably comprises a (semicrystalline) polypropylene as the matrix and an elastomeric propylene copolymer dispersed in said matrix. It is appreciated that at least the propylene homopolymer (HPP-1) is comprised in the heterophasic propylene copolymer (HECO-1) as matrix and that at least the elastomeric propylene copolymer (PC-1) is dispersed in said matrix.

The definitions (including numerical values and ranges) given above for the propylene homopolymer (HPP-1) and the elastomeric propylene copolymer (PC-1) in connection with the heterophasic propylene composition (HC) of the propylene composition (C1) are also applicable for the heterophasic propylene copolymer (HECO-1) .

It is appreciated that the heterophasic propylene copolymer (HECO-1) is nucleated, in particular α-nucleated. Thus, it is appreciated that the heterophasic propylene copolymer (HECO-1) comprises α-nucleating agent. Preferably the heterophasic propylene composition (HC) is free of β-nucleating agent. The disclosure for selecting and applying nucleating agents provided for the heterophasic propylene composition (HC) of the propylene composition (C1) equally applies to the heterophasic propylene copolymer (HECO-1) .

The comonomer content, like ethylene content, of the heterophasic propylene copolymer (HECO-1) may be in the range of 5 to 20 mol ％, preferably in the range of 5 to 15 mol ％.

The comonomer content, like ethylene content, of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-1) is preferably in the range of 30 to 60 mol ％, more preferably in the range of 35 to 55 mol ％, even more preferably in the range of 40 to 55 mol ％

Concerning the definition of comonomers present in the heterophasic propylene copolymer (HECO-1) and/or the definition of the comonomers present in xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-1) , it is referred to the definition of comonomers of the elastomeric propylene copolymer (PC-1) of the propylene composition (C1) .

Preferably the amount of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-1) is not more than 45 wt. -％, preferably not more 35 wt. -％, more preferably not more 20 wt. -％, still more preferably in the range of 5 to 45 wt. -％, yet more preferably in the range of 10 to 35 wt. -％, still yet more preferably in the range of 10 to 20 wt. -％, based on the weight of the heterophasic propylene copolymer (HECO-1) .

The intrinsic viscosity of the xylene soluble fraction (XCS) influences impact strength and flowability of the polypropylene compositions. A high intrinsic viscosity of the xylene soluble fraction (XCS) improves the impact strength but decreases the flowability. Thus, the intrinsic viscosity of the xylene soluble fraction (XCS) needs to be balanced.

It is appreciated that the intrinsic viscosity (IV) measured according to ISO 1268-1 (in decalin at 135 ℃) of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-1) is not more than 3.2 dl/g, preferably not more than 3.0 dl/g, more preferably not more than 2.5 dl/g, like in the range of 1.5 to 3.2 dl/g, preferably in the range of 1.5 to 3.0 dl/g, more preferably in the range of 2.0 to 2.5 dl/g.

The heterophasic propylene copolymer (HECO-1) can be produced by blending the different components, i.e. the propylene homopolymer (HPP-1) and the elastomeric propylene copolymer (PC-1) . Alternatively, the heterophasic propylene copolymer (HECO-1) can be produced in a sequential step process, using reactors in serial configuration and operating at different reaction conditions.

The heterophasic propylene copolymer (HECO-1) is preferably produced in a multistage process known in the art, wherein the matrix, i.e. propylene homopolymer (HPP-1) , is produced at least in one slurry reactor and subsequently the elastomeric copolymer, i.e. propylene copolymer (PC-1) , is produced at least in one, preferably two gas phase reactors. As catalyst a typical Ziegler-Natta catalyst can be employed, reference to WO 92/19653 and WO 99/24479 is made

The heterophasic propylene copolymer (HECO-1) is commercially available.

The Heterophasic Propylene Copolymer (HECO-2)

As indicated above, the expression “heterophasic” indicates that at least one elastomeric copolymer is (finely) dispersed in a matrix. The heterophasic composition (HECO-2) preferably comprises a (semicrystalline) polypropylene as the matrix and an elastomeric propylene copolymer dispersed in said matrix. It is appreciated that at least the propylene homopolymer (HPP-2) is comprised in the heterophasic propylene copolymer (HECO-2) as matrix and that at least the elastomeric propylene copolymer (PC-2) is dispersed in said matrix.

The definitions (including numerical values and ranges) given above for the propylene homopolymer (HPP-2) and the elastomeric propylene copolymer (PC-2) in connection with the heterophasic propylene composition (HC) of the propylene composition (C1) are also applicable for the heterophasic propylene copolymer (HECO-2) .

The comonomer content, like ethylene content, of the heterophasic propylene copolymer (HECO-2) is in the range of 10 to 30 mol ％, preferably in the range of 10 to 25 mol ％, more preferably in the range of 15 to 20 mol ％.

The comonomer content, like ethylene content, of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) is in the range of 30 to 60 mol ％, preferably in the range of 30 to 55 mol ％, more preferably in the range of 40 to 55 mol ％.

Concerning the definition of comonomers present in the heterophasic propylene copolymer (HECO-2) and/or the definition of the comonomers present in xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) , it is referred to the definition of comonomers of the elastomeric propylene copolymer (PC-2) of the propylene composition (C1) .

Preferably the amount of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) is not more than 65 wt. -％, preferably not more 55 wt. -％, more preferably not more 45 wt. -％ (e.g. not more than 40 wt. -％) , still more preferably in the range of 5 to 65 wt. -％, yet more preferably in the range of 15 to 55 wt. -％, still yet more preferably in the range of 10 to 45 wt. -％, like in the range of 25 to 45 wt. -％, based on the weight of the heterophasic propylene copolymer (HECO-2) .

As indicated above, the intrinsic viscosity of the xylene soluble fraction (XCS) influences impact strength and flowability of the polypropylene compositions. A high intrinsic viscosity of the xylene soluble fraction (XCS) improves the impact strength but decreases the flowability. Thus, the intrinsic viscosity of the xylene soluble fraction (XCS) needs to be balanced.

It is appreciated that the intrinsic viscosity (IV) measured according to ISO 1268-1 (in decalin at 135 ℃) of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) is not more than 3.0 dl/g, preferably not more than 2.5 dl/g, like in the range of 1.5 to 3.0 dl/g, preferably in the range of 2.0 to 3.0 dl/g.

The heterophasic propylene copolymer (HECO-2) can be produced by blending the different components, i.e. the propylene homopolymer (HPP-2) and the elastomeric propylene copolymer (PC-2) . Alternatively, the heterophasic propylene copolymer (HECO-2) can be produced in a sequential step process, using reactors in serial configuration and operating at different reaction conditions.

The heterophasic propylene copolymer (HECO-2) is preferably produced in a multistage process known in the art, wherein the matrix, i.e. propylene homopolymer (HPP-2) , is produced at least in one slurry reactor and subsequently the elastomeric copolymer, i.e. propylene copolymer (PC-2) , is produced at least in one, preferably two gas phase reactors. As catalyst a typical Ziegler-Natta catalyst can be employed, reference to WO 92/19653 and WO 99/24479 is made.

The heterophasic propylene copolymer (HECO-2) is commercially available.

The Propylene Homopolymer (HPP-3) , the Elastomeric Ethylene Copolymer (EC) , the Filler (F) , and the Additive (AD)

The definitions given above for the propylene homopolymer (HPP-3) , the elastomeric ethylene copolymer (EC) , the filler (F) , and the additive (AD) , which are defined in detail for the heterophasic propylene composition (HC) of the propylene composition (C1) are also applicable for the propylene composition (C2) .

Accordingly the propylene composition (C2) is a specific embodiment of the propylene composition (C1) .

Automotive Article

In a third aspect the present invention is directed at an automotive article comprising the polypropylene composition (C1) or the polypropylene composition (C2) .

Preferably the automotive article comprises at least 80 wt. -％, like 80 to 99.9 wt. -％, more preferably at least 90 wt. -％, like 90 to 99.9 wt. -％, yet more preferably at least 95 wt. -％, like 95 to 99.9 wt. -％, of the polypropylene composition (C1) or the polypropylene composition (C2) . In one embodiment the automotive article consists of the polypropylene composition (C1) or the polypropylene composition (C2) .

It is appreciated that the automotive article has a flexural modulus of at least 1400 MPa, preferably of at least 1500 MPa, more preferably of at least 1600 MPa, like in the range of 1400 to 1800 MPa, preferably in the range of 1500 to 1700 MPa, more preferably in the range of 1600 to 1700 MPa.

Preferably the automotive article is an automotive interior or exterior article, the latter being preferred. In particular it is preferred that the automotive article is selected from the group consisting of bumper, rock panel and sill plate, the bumper being particularly preferred.

The automotive article is typically a molded article, preferably an injection molded article or a compression molded article. It is appreciated that the automotive article is an injection molded article or a compression molded article, the formerbeing especially preferred.

It is to be understood that the above applies to both the polypropylene composition (C1) and the polypropylene composition (C2) .

Use

In a fourth aspect the present invention is directed at the use of the polypropylene composition (C1) or the polypropylene composition (C2) inan automotive article, preferably an automotive article as described above.

EXAMPLES

1. Definitions/Measuring Methods

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.

Quantification of microstructure by NMR spectroscopy:

Quantitative nuclear-magnetic resonance (NMR) spectroscopy is used to quantify the isotacticity and regio-regularity of the polypropylene homopolymers.

Quantitative ¹³C {¹H} NMR spectra were recorded in the solution-state using a Bruker Advance 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℃ using nitrogen gas for all pneumatics.

For polypropylene homopolymers approximately 200 mg of material was dissolved in 1, 2-tetrachloroethane-d₂ (TCE-d₂) . To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatary oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution needed for tacticity distribution quantification (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443； Busico, V. ； Cipullo, R., Monaco, G.,

Vacatello, M., Segre, A. L., Macromolecules 30 (1997) 6251) . Standard single-pulse excitation was employed utilising the NOE and 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, 11289) . A total of 8192 (8k) transients were acquired per spectra.

Quantitative ¹³C {¹H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs.

For polypropylene homopolymers all chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm.

Characteristic signals corresponding to regio defects (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253；； Wang, W-J., Zhu, S., Macromolecules 33 (2000) , 1157； Cheng, H.N., Macromolecules 17 (1984) , 1950) or comonomer were observed.

The tacticity distribution was quantified through integration of the methyl region between 23.6-19.7 ppm correcting for any sites not related to the stereo sequences of interest (Busico, V., Cipullo, R., Prog. Polym. Sci. 26 (2001) 443； Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A.L., Macromolecules 30 (1997) 6251) .

Specifically the influence of regio-defects and comonomer on the quantification of the tacticity distribution was corrected for by subtraction of representative regio-defect and comonomer integrals from the specific integral regions of the stereo sequences.

The isotacticity was determined at the pentad level and reported as the percentage of isotactic pentad (mmmm) sequences with respect to all pentad sequences:

[mmmm] ％＝ 100 * (mmmm /sum of all pentads)

The presence of 2, 1 erythro regio-defects was indicated by the presence of the two methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic sites. Characteristic signals corresponding to other types of regio-defects were not observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253) .

The amount of 2, 1 erythro regio-defects was quantified using the average integral of the two characteristic methyl sites at 17.7 and 17.2 ppm:

P_21e＝ (I_e6+I_e8) /2

The amount of 1, 2 primary inserted propene was quantified based on the methyl region with correction undertaken for sites included in this region not related to primary insertion and for primary insertion sites excluded from this region:

P₁₂＝ I_CH3+P_12e

The total amount of propene was quantified as the sum of primary inserted propene and all other present regio-defects:

P_total＝ P₁₂+P_21e

The mole percent of 2, 1-erythro regio-defects was quantified with respect to all propene:

[21e] mol. -％＝ 100 * (P_21e/P_total)

Characteristic signals corresponding to the incorporation of ethylene were observed (as described in Cheng, H. N., Macromolecules 1984, 17, 1950) and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer.

The comonomer fraction was quantified using the method of W-J. Wang and S. Zhu, Macromolecules 2000, 33 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.

The weight percent comonomer incorporation was calculated from the mole fraction.

The MFR₂ (230℃) is measured according to ISO 1133 (230℃, 2.16 kg load) .

The MFR₂ (190℃) is measured according to ISO 1133 (190℃, 2.16 kg load) .

The xylene cold solubles (XCS, wt. -％) : Content of xylene cold solubles (XCS) is determined at 25℃ according to ISO 16152； first edition； 2005-07-01.

The Flexural Modulus was determined in 3-point-bending according to ISO 178 on injection molded specimens of 80 x 10 x 4 mm prepared in accordance with ISO 294-1: 1996.

The Particle Size median (D₅₀) and top cut (D₉₅) are calculated from the particle size distribution determined by laser diffraction according to ISO 13320-1: 1999.

The Density is measured according to ISO 1183-1: 2004/Method A. Sample preparation is done by compression molding in accordance with ISO 1872-2: 2007.

Multi Axial Impact (2.2m/s, 23℃ and -30℃) was determined according to ASTM D3763.

The Intrinsic Viscosity is measured according to DIN ISO 1628/1, October 1999 (in decalin at 135 ℃) .

Charpy Impact Test:

The Charpy (notched/unnotched) impact strength (Charpy NIS/IS) is measured according to ISO 179 2C /DIN 53453 at 23℃ and -30℃, using injection molded bar test specimens of 80x10x4 mm³ prepared in accordance with ISO 294-1: 1996.

The Surface Area is determined as the BET surface according to ISO 787-11 with nitrogen (N₂) .

Shrinkage: ISO 294-1

The Weight Reduction Percentage is determined by cutting samples having the size 60 cm x 60 cm from a rear bumper prepared by injection molding of the inventive compositions IE1 and IE2 and the comparative composition CE1, in the area where the number plate is attached. The samples are maintained for 48 h at a temperature of 22 ℃ ± 3 ℃ and a humidity of 50 ％± 5. Subsequently, the weight of the samples is determined with a ME2002/02 of Mettler Toledo International Inc. (Shanghai, China) and the weight reduction ratio is calculated according to formula (V) :

(W₀-W) /W₀ x 100％ (V)

wherein W₀ is the weight of the sample prepared from the comparative composition CE1 and wherein W is the weight of the samples prepared from the inventive compositions IE1 and IE2 respectively.

2. Examples

The present invention is illustrated by the following examples:

The inventive propylene compositions IE1 and IE2 are based on recipes as summarized in Table 1.

Table 1: Recipe and properties of the inventive propylene compositions IE1 and IE2 and properties of the comparative composition CE1

Example		IE1	IE2	CE1
Example		IE1	IE2	CE1	HECO-1	[wt％] *	42.0	45.3
HECO-2	[wt％] *	15.0	23.0		HECO-1	[wt％] *	42.0	45.3
HECO-2	[wt％] *	15.0	23.0		HPP-3	[wt％] *	10.0	0
EC-1	[wt％] *	18	0		HPP-3	[wt％] *	10.0	0
EC-1	[wt％] *	18	0		EC-2	[wt％] *	0	18
F	[wt％] *	13	12.5		EC-2	[wt％] *	0	18
F	[wt％] *	13	12.5
MFR₂ (230 ℃, 2.16 kg)	[g/10min]	24	35	23
MFR₂ (230 ℃, 2.16 kg)	[g/10min]	24	35	23	FlexuralModulus	[MPa]	1650	1600	1650
NIS (23 ℃)	[kJ/m²]	55	50	55	FlexuralModulus	[MPa]	1650	1600	1650
NIS (23 ℃)	[kJ/m²]	55	50	55	NIS (-30 ℃)	[kJ/m²]	5.5	5.0	5.5
Density	[kg/m³]	0.98	0.98	1.05	NIS (-30 ℃)	[kJ/m²]	5.5	5.0	5.5
Density	[kg/m³]	0.98	0.98	1.05	Multi axial Impact (2.2m/s, 23℃)	[J]	18	18	18
Multi axial Impact (2.2m/s, -30℃)	[J]	20	20	20	Multi axial Impact (2.2m/s, 23℃)	[J]	18	18	18
Multi axial Impact (2.2m/s, -30℃)	[J]	20	20	20	Shrinkage	[％]	0.65	0.65	0.65
Weight Reduction Ratio	[％]	6.7	13	0	Shrinkage	[％]	0.65	0.65	0.65

*rest to 100 wt. -％are additives and polymeric carrier material, including the commercial antioxidant “Irganox 1076” of BASF (Germany) , the commercial antioxidant “Irgafos 168 ” of BASF (Germany) , the commercial lubricant “Calcium Stearate S” of Faci S.P.A (Italy) , the commercial surfactant “Rikemal AS-105” of Riken Vitamin Co. Ltd (JP) and the commercial black pigment “MBB206” of Teknor Apex Company (USA) .

“HECO-1” is the heterophasic propylene copolymer as shown in Table 2.

“HECO-2” is the heterophasic propylene copolymer as shown in Table 3.

“HPP-3” is the commercially availablepropylene homopolymer as shown in Table 4.

“EC-1” is the commercial ethylene copolymer “Engange 7467” of The Dow Chemical Company, as shown in Table 4.

“EC-2” is the commercial ethylene copolymer “Engange 8200” of The Dow Chemical Company, as shown in Table 4.

“F” is the commercial talc “Jetfine T1CA” of Imerys Talc (France) , having a median particle size (D₅₀) of 4.2 μm， a cut off particle size (d₉₅) of 8.9 μm and a BET surface area of 12.6 m²/g.

“CE1” is the commercial propylene composition “EF209AEC” of Borouge (Shanghai)

The heterophasic propylene copolymer (HECO-1) used for inventive examples IE 1 and IE2 was prepared by the known

technology, as disclosed in such as EP 0,887,379 A1. The catalyst used in the polymerization process for the preparation of the heterophasic propylene copolymers (HECO-1) and (HECO-3) (inventive examples IE1 and IE2) has been produced as follows: First, 0.1 mol of MgCl₂x 3 EtOH was suspended under inert conditions in 250 ml of decane in a reactor at atmospheric pressure. The solution was cooled to the temperature of–15℃ and 300 ml of cold TiCl₄ was added while maintaining the temperature at said level. Then, the temperature of the slurry was increased slowly to 20 ℃. At this temperature, 0.02 mol of dioctylphthalate (DOP) was added to the slurry. After the addition of the phthalate, the temperature was raised to 135 ℃ during 90 minutes and the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl₄ was added and the temperature was kept at 135 ℃ for 120 minutes. After this, the catalyst was filtered from the liquid and washed six times with 300 ml heptane at 80 ℃. Then, the solid catalyst component was filtered and dried. Catalyst and its preparation concept is described in general e.g. in patent publications EP491566, EP591224 and EP586390. As co-catalyst triethyl-aluminium (TEAL) and as donor dicyclopentyldimethoxysilane [ (C₅H₉) ₂Si (OCH₃) ₂] was used. The aluminium to donor ratio is indicated in table 2.

For the heterophasic propylene copolymer (HECO-2) the catalyst was prepolymerized with vinyl cyclohexane in an amount to achieve a concentration of 200 ppm poly (vinyl cyclohexane) (PVCH) in the final polymer. The respective process is described in EP 1 028 984 and EP 1 183 307.

Table 2: Preparation conditions of heterophasic propylene copolymers HECO-1 and HECO-2

		HECO1	HECO2
		HECO1	HECO2	TEA/Ti	[mol/mol]	220	220
TEAL/Donor	[mol/mol]	10	8.1	TEA/Ti	[mol/mol]	220	220
TEAL/Donor	[mol/mol]	10	8.1	Loop
temperature	[℃]	75	72	Loop
temperature	[℃]	75	72	residence time	[h]	0.6	0.7
H2/C3 ratio	[mol/kmol]	22	14.5	residence time	[h]	0.6	0.7
H2/C3 ratio	[mol/kmol]	22	14.5	MFR₂	[g/10min]	160	55
Split	[wt. -％]	51	35	MFR₂	[g/10min]	160	55
Split	[wt. -％]	51	35	GPR 1
temperature	[℃]	80	80	GPR 1
temperature	[℃]	80	80	pressure	[kPa]	2200	2100
H2/C3 ratio	[mol/kmol]	175	155	pressure	[kPa]	2200	2100
H2/C3 ratio	[mol/kmol]	175	155	MFR₂	[g/10min]	160	55
XCS	[wt. -％]	2.0	2.0	MFR₂	[g/10min]	160	55
XCS	[wt. -％]	2.0	2.0	Split	[wt. -％]	33	30
GPR 2				Split	[wt. -％]	33	30
GPR 2				temperature	[℃]	80	70
pressure	[kPa]	2190	2150	temperature	[℃]	80	70
pressure	[kPa]	2190	2150	H2/C2 ratio	[mol/kmol]	250	108
C2/C3 ratio	[mol/kmol]	550	564	H2/C2 ratio	[mol/kmol]	250	108
C2/C3 ratio	[mol/kmol]	550	564	C2	[mol-％]	11	12
XCS	[wt. -％]	15.0	20	C2	[mol-％]	11	12
XCS	[wt. -％]	15.0	20	C2 (XCS)	[mol-％]	49	48
MFR₂	[g/10min]	95	11	C2 (XCS)	[mol-％]	49	48
MFR₂	[g/10min]	95	11	Split	[wt. -％]	16	19
IV of XCS	[dl/g]	2.3	-	Split	[wt. -％]	16	19
IV of XCS	[dl/g]	2.3	-	GPR 3
temperature	[℃]		84	GPR 3
temperature	[℃]		84	pressure	[kPa]		1500
H2/C2 ratio	[mol/kmol]		87	pressure	[kPa]		1500
H2/C2 ratio	[mol/kmol]		87	C2/C3 ratio	[mol/kmol]		600
C2	[mol-％]		18	C2/C3 ratio	[mol/kmol]		600
C2	[mol-％]		18	XCS	[wt. -％]		32
C2 (XCS)	[mol-％]		48	XCS	[wt. -％]		32
C2 (XCS)	[mol-％]		48	MFR₂	[g/10min]		11
Split	[wt. -％]		16	MFR₂	[g/10min]		11
Split	[wt. -％]		16	IV of XCS	[dl/g]		2.5

Table 3: The propylene homopolymer used and the ethylene copolymers used

		HPP-3	EC-1	EC-2
		HPP-3	EC-1	EC-2	MFR₂ (190 ℃, 2.16 kg)	[g/10min]	1.2	5.0
MFR₂ (230 ℃, 2, 16 kg)	[g/10min]	8.0			MFR₂ (190 ℃, 2.16 kg)	[g/10min]	1.2	5.0
MFR₂ (230 ℃, 2, 16 kg)	[g/10min]	8.0			Density	[kg/cm³]	862	870
Flexural Modulus	[MPa]	2100			Density	[kg/cm³]	862	870

The inventive propylene compositions IE1 and IE2 are produced by melt blending. The inventive compositions are based on the recipe summarized in Tables 1 and are prepared by using a Coperion STS-35 twin-screw extruder (available from Coperion (Nanjing) Corporation, China) with a diameter of 35 mm. The twin-screw extruder runs at an average screw speed of 400 rpm with a temperature profile of zones from 180-220℃. It has a L/D of 44. The temperature of each zone, throughput and the screw speed of the extruder for preparing the compositions of inventive examples IE 1 and IE2 are listed in Table 4.

The temperature of each zone, throughput and screw speed of the extruder are initiative parameters, and are set on control panel of the extruder. Melt temperature (temperature of the melt in the die) and torque of the extruder are passive parameters shown on control panel of the extruder. A vacuum bump is located in zone 9 and generates a vacuum of -0.6 MPa inside the extruder.

Table 4: Extruder conditions of the compositions IE1 to IE2

Process Condition		IE 1	IE 2
Process Condition		IE 1	IE 2	Zone 1 (feeding opening)	[℃]	RT	RT
Zone 2	[℃]	180	180	Zone 1 (feeding opening)	[℃]	RT	RT
Zone 2	[℃]	180	180	Zone 3	[℃]	210	205
Zone 4	[℃]	210	205	Zone 3	[℃]	210	205
Zone 4	[℃]	210	205	Zone 5	[℃]	210	205
Zone 6	[℃]	215	210	Zone 5	[℃]	210	205
Zone 6	[℃]	215	210	Zone 7	[℃]	220	215
Zone 8	[℃]	220	215	Zone 7	[℃]	220	215
Zone 8	[℃]	220	215	Zone 9	[℃]	220	215
Zone 10	[℃]	220	215	Zone 9	[℃]	220	215
Zone 10	[℃]	220	215	Zone 11	[℃]	215	210
Die	[℃]	210	205	Zone 11	[℃]	215	210
Die	[℃]	210	205	Melt Temperature	[℃]	210	205
Throughput	[kg/hour]	60	60	Melt Temperature	[℃]	210	205
Throughput	[kg/hour]	60	60	Screw Speed	[rpm]	580	580
Torque	[％]	52	50	Screw Speed	[rpm]	580	580
Torque	[％]	52	50	Vacuum	[MPa]	-0.6	-0.6

The inventive compositions IE1 and IE2 are used to prepare a bumper by injection-molding with an Engel Duo4000 of Engel Group Company (Austria) . Process conditions are shown in Table 5.

The comparative composition CE1 is used to prepare a bumper by injection-molding with an Engel Duo4000 of Engel Group Company (Austria) at similar process conditions as applied for the preparation of bumpers from inventive compositions IE1 and IE2.

Table 5: Process conditions used to prepare a bumper by injection-molding from inventive compositions IE1 and IE2

	IE 1	IE 2
	IE 1	IE 2	Process Condition	Setting	Setting
Temperature	[℃]	[℃]	Process Condition	Setting	Setting
Temperature	[℃]	[℃]	Zone 1	100	100
Zone 2	225	225	Zone 1	100	100
Zone 2	225	225	Zone 3	235	230
Zone 4	235	235	Zone 3	235	230
Zone 4	235	235	Zone 5	235	230
Zone 6	230	230	Zone 5	235	230
Zone 6	230	230	Zone 7	230	230
Zone 8	220	220	Zone 7	230	230
Zone 8	220	220	Zone 9	220	220
Zone 10	215	215	Zone 9	220	220
Zone 10	215	215	Packing Pressure (bar)	70	65
Packing Time (s)	10	9	Packing Pressure (bar)	70	65
Packing Time (s)	10	9	Injection Speed (mm/s)	45	50
Injection Pressure (bar)	120	120	Injection Speed (mm/s)	45	50
Injection Pressure (bar)	120	120	Injection Time (s)	15	14
Cooling Time (s)	20	20	Injection Time (s)	15	14
Cooling Time (s)	20	20	Cycle Time (s)	60	57

The bumper prepared from the inventive composition IE1 (having a MFR₂ of 24g/10 min) has an average thickness of 2.8 mm.

The bumper prepared from the inventive composition IE2 (having a MFR₂ of 35g/10min) has an average thickness of 2.5mm.

The reduction in average thickness contributes to the weight reduction besides the lower density of inventive compositions IE 1 and IE 2 compared to the density of the comparative composition CE1. Only a composition with a MFR₂ (230℃, 2.16kg) of at least 18 g/10min. can be used to prepare a thin-wall bumper (such as 2.5mm average thickness) by injection-molding.

From Table 1, it can be seen that the inventive compositions IE1 and IE2 have similar properties as to the comparative composition CE1. Furthermore, it can be seen that bumpers prepared from the inventive composition IE1 show a weight reduction of 6.7 ％compared to bumpers prepared from comparative composition CE1, due to a reduced density.

Furthermore, it can be seen that bumpers prepared from the inventive composition IE2 show a weight reduction of 13 ％compared to bumpers prepared from comparative composition CE1, due to a reduced density and a reduced average thickness.

Claims

Polypropylene composition (C1) comprising

(c) a heterophasic propylene composition (HC) comprising

(a1) a matrix (M) comprising a propylene homopolymer (HPP-1) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 100 g/10 min, and a propylene homopolymer (HPP-2) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 in the range of 30 to 90 g/10 min, and

(a2) an elastomeric propylene copolymer (PC-1) , an elastomeric propylene copolymer (PC-2) and an elastomeric ethylene copolymer (EC) comprising units derived from ethylene and units derived from C₄-C₂₀ α-olefin, and

(d) a filler (F) .
Polypropylene composition (C1) according to claim 1, wherein the matrix (M) additionally comprises a propylene homopolymer (HPP-3) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 25 g/10 min.
Polypropylene composition (C1) according to any one of the previous claims, wherein the heterophasic propylene composition (HC) comprises

(a) the matrix (M) in an amount of at least 50 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(b) the elastomeric propylene copolymer (PC-1) , the elastomeric propylene copolymer (PC-2) and the elastomeric ethylene copolymer (EC) together in an amount of not more than 50 wt. -％, based on the weight of the heterophasic propylene composition (HC) .
Polypropylene composition (C1) according to any one of the previous claims, wherein the heterophasic propylene composition (HC) comprises

(a) the propylene homopolymer (HPP-1) in an amount in the range of 25 to 60 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(b) the propylene homopolymer (HPP-2) in an amount in the range of 5 to 30 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(c) the propylene homopolymer (HPP-3) in an amount in the range of 0 to 20 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(d) elastomeric propylene copolymer (PC-1) in an amount in the range of 2 to 15 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(e) elastomeric propylene copolymer (PC-2) in an amount in the range of 2 to 15 wt. -％, based on the weight of the heterophasic propylene composition (HC) ,

and/or

(f) the elastomeric ethylene copolymer (EC) in an amount in the range of 10 to 35 wt. -％, based on the weight of the heterophasic propylene composition (HC) .
Polypropylene composition (C1) according to any one of the previous claims, wherein the filler (F) is comprised in an amount of not more than 30 wt. -％, based on the weight of the polypropylene composition (C1) .
Polypropylene composition (C2) comprising

(a) a heterophasic propylene copolymer (HECO-1) comprising

(a1) a propylene homopolymer (HPP-1) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of at least 100 g/10 min, and

(a2) an elastomeric propylene copolymer (PC-1) ,

(b) a heterophasic propylene copolymer (HECO-2) comprising

(b1) a propylene homopolymer (HPP-2) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 in the range of 30 to 90 g/10 min, and

(b2) an elastomeric propylene copolymer (PC-2) ,

(c) an elastomeric copolymer (EC) comprising units derived from ethylene and units derived from C₄-C₂₀ α-olefin
Polypropylene composition (C2) according to claim 6, wherein the polypropylene composition additionally comprises propylene homopolymer (HPP-3) with a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 of not more than 25 g/10 min.
Polypropylene composition (C2) according to claim 6 or 7, wherein the polypropylene composition comprises

(a) the heterophasic propylene copolymer (HECO-1) in an amount of at least 25 wt. -％, based on the weight of the polypropylene composition (C2) ,

and/or

(b) the heterophasic propylene copolymer (HECO-2) in an amount in the range of 8 to 35 wt. -％, based on the weight of the polypropylene composition (C2) ,

and/or

(c) the elastomeric ethylene copolymer (EC) in an amount in the range of 8 to 30 wt. -％, based on the weight of the polypropylene composition (C2) ,

and/or

(d) the filler (F) in an amount in the range of 1 to 30 wt. -％, based on the weight of the polypropylene composition (C2) ,

and/or

(e) the propylene homopolymer (HPP-3) in an amount in the range of 0 to 20 wt. -％, based on the weight of the polypropylene composition (C2) .
Polypropylene composition (C2) according to any one of the previous claims 6 to 8, wherein

(a) the comonomer content of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-1) is in the range of 30 to 50 mol ％,

and/or

(b) the comonomer content of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) is in the range of 30 to 50 mol ％, based on the weight of the heterophasic propylene copolymer (HECO-2) .
Polypropylene composition (C2) according to any one of the previous claims 6 to 9, wherein

(a) the comonomer content of the heterophasic propylene copolymer (HECO-1) is in the range of 5 to 20 mol ％, based on the weight of the heterophasic propylene copolymer (HECO-1) ,

and/or

(b) the comonomer content of the heterophasic propylene copolymer (HECO-2) is in the range of 10 to 30 mol ％, based on the weight of the heterophasic propylene copolymer (HECO-2) .
Polypropylene composition (C2) according to any one of the previous claims 6 to 10, wherein

(a) the intrinsic viscosity (IV) measured according to ISO 1268-1 (decalin) of the xylene soluble fraction (XCS) ofthe heterophasic propylene copolymer (HECO-1) is in the range of 1.5 to 3.0 dl/g,

and/or

(b) the intrinsic viscosity (IV) measured according to ISO 1268-1 (decalin) of the xylene soluble fraction (XCS) of the heterophasic propylene copolymer (HECO-2) is in the range of 1.5 to 3.2 dl/g.
Polypropylene composition (C1) according to any one of the previous claims 1 to 5, or polypropylene composition (C2) according to any one of the previous claims 6 to 11, wherein the elastomeric ethylene copolymer (EC) has

(a) a melt flow rate MFR₂ (190 ℃, 2.16 kg) measured according to ISO 1133 in the range of 0.1 to 15 g/10 min,

and/or

(b) a density in the range of 830 to 890 kg/cm³.
Polypropylene composition (C1) according to any one of the previous claims 1 to 5 and 12, or polypropylene composition (C2) according to any one of the previous claims 6 to 12, wherein the polypropylene composition has a melt flow rate MFR₂ (230 ℃, 2.16 kg) measured according to ISO 1133 in the range of 18 to 50 g/10 min.
Automotive article comprising the polypropylene composition (C1) according to any one of the previous claims 1 to 5 and 12 to 13, or polypropylene composition (C2) according to any one of the previous claims 6 to 12
Use of the polypropylene composition (C1) according to any one of the previous claims 1 to 5 and 12 to 13, or the polypropylene composition (C2) according to any one of the previous claims 6 to 12 in an automotive article.