High flow TPO composition with excellent tensile strain at break and low powder stickiness

Abstract

The present invention is directed to a heterophasic propylene copolymer (HECO), a polyolefin composition (PO) comprising the heterophasic propylene copolymer (HECO), an automotive article comprising the heterophasic propylene copolymer (HECO) and/or the polyolefin composition (PO) and a process for the preparation of the polyolefin composition (PO) as well as the use of the heterophasic propylene copolymer (HECO) for improving the mechanical properties of a polyolefin composition (PO).

Claims

1. A heterophasic propylene copolymer (HECO) comprising a) a propylene homopolymer (HPP) having a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 100 to 300 g/10 min, and b) an elastomeric propylene-ethylene copolymer (E), wherein the heterophasic propylene copolymer (HECO) (i) has a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, (ii) comprises a xylene cold soluble (XCS) fraction in an amount from 28 to 38 wt.-%, based on the total weight of the heterophasic propylene copolymer (HECO), wherein further the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO) has (iii) an intrinsic viscosity (IV) in the range of 2.5 to 3.5 dl/g, and (iv) an ethylene content (EC) of 15 to 35 wt.-% based on the total weight of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO).

2. The heterophasic propylene copolymer (HECO) according to claim 1, wherein the propylene homopolymer (HPP) is unimodal with respect to the melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133, has a xylene cold soluble (XCS) content no higher than 5 wt.-%, or is unimodal with respect to the melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 and has a xylene cold soluble (XCS) content no higher than 5 wt.-%.

3. The heterophasic propylene copolymer (HECO) according to claim 1, wherein the heterophasic propylene copolymer (HECO) has an ethylene content (EC-HECO) of 7 to 15 wt.-%, based on the total weight of the heterophasic propylene copolymer (HECO).

4. The heterophasic propylene copolymer (HECO) according to claim 1, wherein the xylene cold soluble (XCS) fraction is unimodal with respect to the ethylene content (EC), unimodal with respect to a molecular weight distribution (MWD), or unimodal with respect to the ethylene content (EC) and with respect to the molecular weight distribution (MWD).

5. The heterophasic propylene copolymer (HECO) according to claim 1, wherein the weight ratio of heterophasic propylene copolymer (HECO) to the polypropylene homopolymer (HPP) [HECO/HPP] is from 3.0:1.0 to 1.0:1.0.

6. The heterophasic propylene copolymer (HECO) according to claim 1, wherein the heterophasic propylene copolymer (HECO) is -nucleated.

7. A polyolefin composition (PO) comprising 95 wt.-%, based on the total weight of the composition, of the heterophasic propylene copolymer (HECO) according to claim 1.

8. The polyolefin composition (PO) according to claim 7, wherein the composition comprises an inorganic filler (F).

9. The polyolefin composition (PO) according to claim 7, wherein the composition has i) a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, and one or more of: ii) a tensile modulus of 750 MPa, or iii) a Charpy Notched impact strength at 23 C. of 30 kJ/m2, or iv) a tensile strain at break of 150%.

10. The polyolefin composition (PO) according to claim 9, wherein the composition has one or more of: i) a tensile modulus in the range of 750 to 1100 MPa, or ii) a Charpy Notched impact strength at 23 C. in the range of 30 to 80 kJ/m2, or iii) a tensile strain at break in the range of 150 to 400%.

11. An automotive article comprising at least one of a heterophasic propylene copolymer (HECO) and a polyolefin composition (PO), wherein the heterophasic propylene copolymer (HECO) comprises a) a propylene homopolymer (HPP) having a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 100 to 300 g/10 min, and b) an elastomeric propylene-ethylene copolymer (E), wherein the heterophasic propylene copolymer (HECO) (i) has a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, (ii) comprises a xylene cold soluble (XCS) fraction in an amount from 28 to 38 wt.-%, based on the total weight of the heterophasic propylene copolymer (HECO), wherein further the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO) has (iii) an intrinsic viscosity (IV) in the range of 2.5 to 3.5 dl/g, and (iv) an ethylene content (EC) of 15 to 35 wt.-% based on the total weight of the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO), and wherein the polyolefin composition (PO) comprises 95 wt.-%, based on the total weight of the polyolefin composition (PO) of the heterophasic propylene copolymer (HECO).

12. The automotive article according to claim 11, wherein the automotive article is an exterior or interior automotive article selected from bumpers, body panels, rocker panels, side trim panels, interior trims, step assists, spoilers, fenders and dash boards.

13. A process for the preparation of a polyolefin composition (PO) according to claim 7, the process comprising extruding the heterophasic propylene copolymer (HECO) and the optional inorganic filler (F) in an extruder.

14. The process according to claim 13, wherein the heterophasic propylene copolymer (HECO) is obtained by producing the propylene homopolymer (HPP) in at least one reactor, transferring said propylene homopolymer (HPP) in at least one subsequent reactor, and producing the elastomeric propylene-ethylene copolymer (E) in the presence of the propylene homopolymer (HPP).

15. A method comprising improving the mechanical properties of a polyolefin composition (PO) with the heterophasic propylene copolymer (HECO) according to claim 1, wherein the improvement is achieved when the composition has i) a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, and one or more of ii) a tensile modulus of 750 MPa, or iii) a Charpy Notched impact strength at 23 C. of 30 kJ/m2, or iv) a tensile strain at break of 150%.

16. The heterophasic propylene copolymer (HECO) according to claim 6, wherein the heterophasic propylene copolymer (HECO) comprises a -nucleating agent.

17. The polyolefin composition (PO) according to claim 8, wherein the inorganic filler (F) is selected from the group consisting of talc, wollastonite, mica, chalk and mixtures thereof.

18. The polyolefin composition (PO) according to claim 8, wherein the composition has i) a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 20 to 35 g/10 min, and one or more of: ii) a tensile modulus of 750 MPa, or iii) a Charpy Notched impact strength at 23 C. of 30 kJ/m2, or iv) a tensile strain at break of 150%.

19. The polyolefin composition (PO) according to claim 18, wherein the composition has one or more of: i) a tensile modulus in the range of 750 to 1100 MPa, or ii) a Charpy Notched impact strength at 23 C. in the range of 30 to 80 kJ/m2, or iii) a tensile strain at break in the range of 150 to 400%.

Description

EXAMPLES

(1) A. Measuring Methods

(2) 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.

(3) Calculation of Comonomer Content of the Second Fraction (F2):

(4) $\frac{C\left(R2\right)-w\left(F1\right)C\left(F1\right)}{w\left(F2\right)}=C\left(F2\right)$
wherein

(5) TABLE-US-00001 w(F1) is the weight fraction of the first fraction (F1), i.e. the product of the first reactor (R1), w(F2) is the weight fraction of the second fraction (F2), i.e. of the polymer produced in the second reactor (R2), C(F1) is the comonomer content [in wt.-%] of the first fraction (F1), i.e. of the product of the first reactor (R1), C(R2) is the comonomer content [in wt.-%] of the product obtained in the second reactor (R2), i.e. the mixture of the first fraction (F1) and the second fraction (F2), C(F2) is the calculated comonomer content [in wt.-%] of the second fraction (F2).
Calculation of the Xylene Cold Soluble (XCS) Content of the Second Fraction (F2):

(6) $\frac{\mathrm{XS}\left(R2\right)-w\left(F1\right)\mathrm{XS}\left(F1\right)}{w\left(F2\right)}=\mathrm{XS}\left(F2\right)$
wherein

(7) TABLE-US-00002 w(F1) is the weight fraction of the first fraction (1), i.e. the product of the first reactor (R1), w(F2) is the weight fraction of the second fraction (F2), i.e. of the polymer produced in the second reactor (R2), XS(F1) is the xylene cold soluble (XCS) content [in wt.-%] of the first fraction (F1), i.e. of the product of the first reactor (R1), XS(R2) is the xylene cold soluble (XCS) content [in wt.-%] of the product obtained in the second reactor (R2), i.e. the mixture of the first fraction (F1) and the second fraction (F2), XS(F2) is the calculated xylene cold soluble (XCS) content [in wt.-%] of the second fraction (F2).
Calculation of Melt Flow Rate MFR.sub.2 (230 C.) of the Second Fraction (F2):

(8) $\mathrm{MFR}\left(F2\right)={10}^{\left[\frac{\log \left(\mathrm{MFR}\left(R2\right)\right)-w\left(F1\right)\log \left(\mathrm{MFR}\left(F1\right)\right)}{w\left(F2\right)}\right]}$
wherein

(9) TABLE-US-00003 w(F1) is the weight fraction of the first fraction (F1), i.e. the product of the first reactor (R1), w(F2) is the weight fraction of the second fraction (F2), i.e. of the polymer produced in the second reactor (R2), MFR(F1) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the first fraction (F1), i.e. of the product of the first reactor (R1), MFR(R2) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the product obtained in the second reactor (R2), i.e. the mixture of the first fraction (F1) and the second fraction (F2), MFR(F2) is the calculated melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the second fraction (F2).
Calculation of Comonomer Content of the Third Fraction (F3):

(10) $\frac{C\left(R3\right)-w\left(R2\right)C\left(R2\right)}{w\left(F3\right)}=C\left(F3\right)$
wherein

(11) TABLE-US-00004 w(R2) is the weight fraction of the second reactor (R2), i.e. the mixture of the first fraction (1) and the second fraction (F2), w(F3) is the weight fraction of the third fraction (F3), i.e. of the polymer produced in the third reactor (R3), C(R2) is the comonomer content [in wt.-%] of the product of the second reactor (R2), i.e. of the mixture of the first fraction (F1) and second fraction (F2), C(R3) is the comonomer content [in wt.-%] of the product obtained in the third reactor (R3), i.e. the mixture of the first fraction (F1), the second fraction (F2), and the third fraction (F3), C(F3) is the calculated comonomer content [in wt.-%] of the third fraction (F3).
Calculation of Xylene Cold Soluble (XCS) Content of the Third Fraction (F3):

(12) $\frac{\mathrm{XS}\left(R3\right)-w\left(R2\right)\mathrm{CS}\left(R2\right)}{w\left(F3\right)}=\mathrm{XS}\left(F3\right)$
wherein

(13) TABLE-US-00005 w(R2) is the weight fraction of the second reactor (R2), i.e. the mixture of the first fraction (F1) and the second fraction (F2), w(F3) is the weight fraction of the third fraction (F3), i.e. of the polymer produced in the third reactor (R3), XS(R2) is the xylene cold soluble (XCS) content [in wt.-%] of the product of the second reactor (R2), i.e. of the mixture of the first fraction (F1) and second fraction (F2), XS(R3) is the xylene cold soluble (XCS) content [in wt.-%] of the product obtained in the third reactor (R3), i.e. the mixture of the first fraction (F1), the second fraction (F2), and the third fraction (F3), XS(F3) is the calculated xylene cold soluble (XCS) content [in wt.-%] of the third fraction (F3).
Calculation of melt flow rate MFR.sub.2 (230 C.) of the third fraction (F3):

(14) $\mathrm{MFR}\left(F3\right)={10}^{\left[\frac{\log \left(\mathrm{MFR}\left(R3\right)\right)-w\left(R2\right)\log \left(\mathrm{MFR}\left(R2\right)\right)}{w\left(F3\right)}\right]}$
wherein

(15) TABLE-US-00006 w(R2) is the weight fraction of the second reactor (R2), i.e. the mixture of the first fraction (F1) and the second fraction (F2), w(F3) is the weight fraction of the third fraction (F3), i.e. of the polymer produced in the third reactor (R3), MFR(R2) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the product of the second reactor (R2), i.e. of the mixture of the first fraction (F1) and second fraction (F2), MFR(R3) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the product obtained in the third reactor (R3), i.e. the mixture of the first fraction (F1), the second fraction (F2), and the third fraction (F3), MFR(F3) is the calculated melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the third fraction (F3).
Calculation of Comonomer Content of the Fourth Fraction (F4):

(16) $\frac{C\left(R4\right)-w\left(R3\right)C\left(R3\right)}{w\left(F4\right)}=C\left(F4\right)$
wherein

(17) TABLE-US-00007 w(R3) is the weight fraction of the third reactor (R3), i.e. the mixture of the first fraction (F1), the second fraction (F2) and the fourth fraction (F3), w(F4) is the weight fraction of the fourth fraction (F4), i.e. of the polymer produced in the fourth reactor (R4), C(R3) is the comonomer content [in wt.-%] of the product of the third reactor (R3), i.e. of the mixture of the first fraction (F1), the second fraction (F2) and the third fraction (F3), C(R4) is the comonomer content [in wt.-%] of the product obtained in the fourth reactor (R4), i.e. the mixture of the first fraction (F1), the second fraction (F2), the third fraction (F3) and the fourth fraction (F4), C(F4) is the calculated comonomer content [in wt.-%] of the fourth fraction (F4).
Calculation of Xylene Cold Soluble (XCS) Content of the Fourth Fraction (F4):

(18) $\frac{\mathrm{XS}\left(R4\right)-w\left(R3\right)\mathrm{XS}\left(R3\right)}{w\left(F4\right)}=\mathrm{XS}\left(F4\right)$
wherein

(19) TABLE-US-00008 w(R3) is the weight fraction of the third reactor (R3), i.e. the mixture of the first fraction (F1), the second fraction (F2) an the third fraction (F3), w(F4) is the weight fraction of the fourth fraction (F4), i.e. of the polymer produced in the fourth reactor (R4), XS(R3) is the xylene cold soluble (XCS) content [in wt.-%] of the product of the third reactor (R3), i.e. of the mixture of the first fraction (F1), the second fraction (F2) and the third fraction (F3), XS(R4) is the xylene cold soluble (XCS) content [in wt.-%] of the product obtained in the fourth reactor (R4), i.e. the mixture of the first fraction (F1), the second fraction (F2), the third fraction (F3) and the fourth fraction, XS(F4) is the calculated xylene cold soluble (XCS) content [in wt.-%] of the fourth fraction (F4).
Calculation of Melt Flow Rate MFR.sub.2 (230 C.) of the Fourth Fraction (F4):

(20) $\mathrm{MFR}\left(F4\right)={10}^{\left[\frac{\log \left(\mathrm{MFR}\left(R4\right)\right)-w\left(R3\right)\log \left(\mathrm{MFR}\left(R3\right)\right)}{w\left(F4\right)}\right]}$
wherein

(21) TABLE-US-00009 w(R3) is the weight fraction of the third reactor (R3), i.e. the mixture of the first fraction (F1), the second fraction (F2) an the third fraction (F3), w(F4) is the weight fraction of the fourth fraction (F4), i.e. of the polymer produced in the fourth reactor (R4), MFR(R3) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the product of the third reactor (R3), i.e. of the mixture of the first fraction (F1), the second fraction (F2) and the third fraction (F3), MFR(R4) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the product obtained in the fourth reactor (R4), i.e. the mixture of the first fraction (F1), the second fraction (F2), the third fraction (F3) and the fourth fraction (F4), MFR(F4) is the calculated melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the fourth fraction (F4).
NMR-Spectroscopy Measurements:

(22) The .sup.13C-NMR spectra of polypropylenes were recorded on Bruker 400 MHz spectrometer at 130 C. from samples dissolved in 1,2,4-trichlorobenzene/benzene-d6 (90/10 w/w). For the pentad analysis the assignment is done according to the methods described in literature: (T. Hayashi, Y. Inoue, R. Chj, and T. Asakura, Polymer 29 138-43 (1988). and Chujo R, et al, Polymer 35 339 (1994).

(23) The NMR-measurement was used for determining the mmmm pentad concentration in a manner well known in the art.

(24) Quantification of Comonomer Content by FTIR Spectroscopy

(25) The comonomer content is determined by quantitative Fourier transform infrared spectroscopy (FTIR) after basic assignment calibrated via quantitative .sup.13C nuclear magnetic resonance (NMR) spectroscopy in a manner well known in the art. Thin films are pressed to a thickness of between 100-500 m and spectra recorded in transmission mode.

(26) Specifically, the ethylene content of a polypropylene-co-ethylene copolymer is determined using the baseline corrected peak area of the quantitative bands found at 720-722 and 730-733 cm.sup.1. Specifically, the butene or hexene content of a polyethylene copolymer is determined using the baseline corrected peak area of the quantitative bands found at 1377-1379 cm.sup.1. Quantitative results are obtained based upon reference to the film thickness.

(27) Density is measured according to ISO 1183-187. Sample preparation is done by compression moulding in accordance with ISO 1872-2:2007.

(28) MFR.sub.2 (230 C.) is measured according to ISO 1133 (230 C., 2.16 kg load).

(29) MFR.sub.2 (190 C.) is measured according to ISO 1133 (190 C., 2.16 kg load).

(30) Intrinsic viscosity is measured according to DIN ISO 1628/1, October 1999 (in Decalin at 135 C.).

(31) Xylene cold soluble fraction (XCS wt.-%): Content of xylene cold solubles (XCS) is determined at 25 C. according ISO 16152; first edition; 2005 Jul. 1. The part which remains insoluble is the xylene cold insoluble (XCI) fraction.

(32) Melting temperature T.sub.m, crystallization temperature T.sub.e, is measured with Mettler TA820 differential scanning calorimetry (DSC) on 5-10 mg samples. Both crystallization and melting curves were obtained during 10 C./min cooling and heating scans between 30 C. and 225 C. Melting and crystallization temperatures were taken as the peaks of endotherms and exotherms.

(33) Also the melt- and crystallization enthalpy (Hm and Hc) were measured by the DSC method according to ISO 11357-1.

(34) Number average molecular weight (M.sub.n), weight average molecular weight (M.sub.w) and molecular weight distribution (MWD) are determined by Gel Permeation Chromatography (GPC) according to the following method:

(35) The weight average molecular weight Mw and the molecular weight distribution (MWD=Mw/Mn wherein Mn is the number average molecular weight and Mw is the weight average molecular weight) is measured by a method based on ISO 16014-1:2003 and ISO 16014-4:2003. A Waters Alliance GPCV 2000 instrument, equipped with refractive index detector and online viscosimeter was used with 3TSK-gel columns (GMHXL-HT) from TosoHaas and 1,2,4-trichlorobenzene (TCB, stabilized with 200 mg/L 2,6-Di tert butyl-4-methyl-phenol) as solvent at 145 C. and at a constant flow rate of 1 mL/min. 216.5 L of sample solution were injected per analysis. The column set was calibrated using relative calibration with 19 narrow MWD polystyrene (PS) standards in the range of 0.5 kg/mol to 11 500 kg/mol and a set of well characterized broad polypropylene standards. All samples were prepared by dissolving 5-10 mg of polymer in 10 mL (at 160 C.) of stabilized TCB (same as mobile phase) and keeping for 3 hours with continuous shaking prior sampling in into the GPC instrument.

(36) Median particle size d.sub.50 (Sedimentation) is calculated from the particle size distribution [mass percent] as determined by gravitational liquid sedimentation according to ISO 13317-3 (Sedigraph).

(37) Tensile Modulus; Tensile strain at break were measured according to ISO 527-2 (cross head speed=50 mm/min; 23 C.) using injection molded specimens as described in EN ISO 1873-2 (dog bone shape, 4 mm thickness).

(38) Flexural modulus was measured according to ISO 178 using injection molded test specimen as described in EN ISO 1873-2 with dimensions of 80104 mm.sup.3. Crosshead speed was 2 mm/min for determining the flexural modulus.

(39) Charpy impact test: The Charpy notched impact strength (Charpy NIS) is measured according to ISO 179-1/1 eA/DIN 53453 at 23 C., 20 C. and 30 C., using injection molded bar test specimens of 80104 mm.sup.3 mm.sup.3 prepared in accordance with ISO 294-1:1996.

(40) Shrinkage (SH) radial; Shrinkage (SH) tangential were determined on centre gated, injection moulded circular disks (diameter 180 mm, thickness 3 mm, having a flow angle of 355 and a cut out of 5). Two specimens are moulded applying two different holding pressure times (10 s and 20 s respectively). The melt temperature at the gate is 260 C., and the average flow front velocity in the mould 100 mm/s. Tool temperature: 40 C., back pressure: 600 bar.

(41) After conditioning the specimen at room temperature for 96 hours the dimensional changes radial and tangential to the flow direction are measured for both disks. The average of respective values from both disks are reported as final results.

(42) Cutoff particle size d.sub.95 (Sedimentation) is calculated from the particle size distribution [mass percent] as determined by gravitational liquid sedimentation according to ISO 13317-3 (Sedigraph).

2. Examples

(43) All polymers were produced in a Borstar pilot plant with a prepolymerization reactor, one slurry loop reactor and three gas phase reactors. The catalyst used in the polymerization process for the inventive example was the commercially available BCF55P catalyst (1.9 wt.-% Ti-Ziegler-Natta-catalyst as described in EP 591 224) of Borealis AG with triethylaluminium (TEAL) as cocatalyst and diethylaminotriethoxysilane [Si(OCH.sub.2CH.sub.3).sub.3(N(CH.sub.2CH.sub.3).sub.2)] (U donor) or dicyclo pentyl dimethoxy silane (D-donor). The preparation of the heterophasic propylene copolymer (HECO) comprising the propylene homopolymer (HPP) and the elastomeric propylene-ethylene copolymer (E) including the aluminium to donor ratio is described in the following Table 1. Table 1 also outlines the preparation conditions for the comparative examples (CE).

(44) Table 2 summarizes the property profiles of the inventive heterophasic propylene copolymers (HECO) and the comparative examples (CE).

(45) TABLE-US-00010 TABLE 1 Polymerization conditions of the inventive heterophasic propylene copolymers (HECO) and comparative examples (CE) HECO1 HECO2 HECO3 HECO4 CE1 CE2 CE3 CE4 Donor D D D D D D D U TEAL/D [mol/mol] 10 10 10 10 10 13 13 11 Matrix split [wt.-%] 59 61 63 63 61 63 67 66 MFR.sub.2 [g/10 min] 162 162 162 163 63 113 77 300 E Split [wt.-%] 41 39 37 37 39 37 33 34 H2/C3 ratio [mol/kmol] 200 200 200 200 140 140 140 36/152* C2/C3 ratio [mol/kmol] 300 300 300 300/150* 155 155 555 440 *bimodal

(46) TABLE-US-00011 TABLE 2 Properties of the heterophasic propylene copolymers (HECO) and the comparative examples (CE) Example HECO1 HECO2 HECO3 HECO4 CE1 CE2 CE3 CE4 Matrix [wt.-%] 65 67 68 69 65 63 72 63 MFR.sub.2 Matrix [g/10 min] 162 162 162 163 63 113 77 300 XCS [wt.-%] 35 33 32 31 35 37 28 37 IV (XCS) [dl/g] 2.9 2.9 3.0 2.5 3.1 3.3 3.3 3.0 C2 (XCS) [wt %] 32 32 32 27.5 40 41 41 47 MFR.sub.2total [g/10 min] 23 25 26 22 13 18 21 30 C2 total [wt %] 13 12 11 9.3 15 15.7 nd 20.1 Tensile [MPa] 813 953 1010 903 856 844 1203 760 modulus Tensile strain [%] 312 287 192 316 221 67 46 14 at break Charpy [kJ/m.sup.2] 67 64 59 63 69 68 16.2 52 NIS +23 C. Charpy [kJ/m.sup.2] 13.6 10.3 9.3 8.4 13.5 15.3 6.8 13.4 NIS 20 C. SH radial [%] 1.50 1.57 1.60 1.60 1.55 1.54 1.65 1.66 SH tangential [%] 1.32 1.41 1.45 1.43 1.33 1.38 1.52 1.48 nd: not determiner .sup.#: values were calculated

(47) In contrast to the comparative examples, the inventive materials HECO1, HECO2, HECO3 and HECO4 provide an excellent combination of mechanical properties. In particular, it can be gathered that the inventive heterophasic propylene copolymers (HECO) provide good flowability in combination with good stiffness/toughness balance and excellent tensile strain at break.