Polypropylene composition with excellent paint adhesion

Abstract

The invention relates to a polypropylene composition (C) comprising: (i) 62 to 85 wt.-%, based on the total weight of the polypropylene composition (C), of a heterophasic propylene copolymer (HECO1) with a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 6.0 to 50.0 g/10 min; (ii) 10 to 30 wt.-%, based on the total weight of the polypropylene composition (C), of a heterophasic propylene copolymer (HECO2) with a melt flow rate MFR.sub.2 (230 C.) measured according to ISO 1133 in the range of 0.1 to 5.5 g/10 min; (iii) 5 to 30 wt.-%, based on the total weight of the polypropylene composition (C), of an inorganic filler (F); wherein (a) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO1) has a lower amount [in mol %] of C.sub.2 and/or C.sub.4 to C.sub.12 -olefin derived comonomer units than the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2); (b) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO1) has a lower the intrinsic viscosity (IV) than the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2); and (c) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2) has an intrinsic viscosity (IV) in the range of 6.0 to 15.0 dl/g.

Claims

1. Polypropylene composition (C) comprising: (i) 62 to 85 wt. %, based on the total weight of the polypropylene composition (C), of a heterophasic propylene copolymer (HECO1) with a melt flow rate MFR.sub.2 measured according to ISO 1133 at 230 C., 2.16 kg load in the range of 6.0 to 50.0 g/10 min; (ii) 10 to 30 wt. %, based on the total weight of the polypropylene composition (C), of a heterophasic propylene copolymer (HECO2) with a melt flow rate MFR.sub.2 measured according to ISO 1133 at 230 C., 2.16 kg load in the range of 0.1 to 5.5 g/10 min; (iii) 5 to 30 wt. %, based on the total weight of the polypropylene composition (C), of an inorganic filler (F); wherein (a) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO1) has a lower amount [in mol %] of C.sub.2 and/or C.sub.4 to C.sub.12 -olefin derived comonomer units than the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2); (b) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO1) has a lower the intrinsic viscosity (IV) than the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2); and (c) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2) has an intrinsic viscosity (IV) in the range of 6.0 to 15.0 dl/g, and wherein (d) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2) comprises comonomer units derived from C2 and/or C4 to C12 -olefin in an amount in the range of 62 to 85 mol %.

2. Polypropylene composition (C) according to claim 1, wherein the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO1) comprises comonomer units derived from C.sub.2 and/or C.sub.4 to C.sub.12 -olefin in an amount in the range of 35 to 60 mol %.

3. Polypropylene composition (C) according to claim 1, wherein the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO1) has an intrinsic viscosity (IV) in the range of 0.8 to 5.5 dl/g.

4. Polypropylene composition (C) according to claim 1, wherein: (i) the heterophasic propylene copolymer (HECO1) comprises a (semi)crystalline polypropylene matrix (PM1) and an elastomeric propylene copolymer rubber (EPR1) dispersed in said (semi)crystalline polypropylene matrix (PM1); and (ii) the heterophasic propylene copolymer (HECO2) comprises a (semi)crystalline polypropylene matrix (PM2) and an elastomeric propylene copolymer rubber (EPR2) dispersed in said (semi)crystalline polypropylene matrix (PM2).

5. Polypropylene composition (C) according to claim 1, wherein the heterophasic propylene copolymer (HECO1) and the heterophasic propylene copolymer (HECO2) are not modified by treatment with a peroxide (PO).

6. Polypropylene composition (C) according to claim 1, wherein the inorganic filler (F) is a mineral filler.

7. Polypropylene composition (C) according to claim 6, wherein the inorganic filler (F) is talc with an average particle size (D.sub.50) in the range of 0.5 to 20.0 calculated from the particle size distribution [mass percent] as determined by gravitational liquid sedimentation according to ISO 13317-3 (Sedigraph).

8. Heterophasic propylene copolymer (HECO2), wherein: (i) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2) has an intrinsic viscosity (IV) of in the range of 6.0 to 15.0 dl/g; (ii) the xylene cold soluble (XCS) fraction of the heterophasic propylene copolymer (HECO2) comprises comonomer units derived from C.sub.2 and/or C.sub.4 to C.sub.12 -olefin in an amount in the range of 62 to 85 mol %; and (iii) a melt flow rate MFR.sub.2 measured according to ISO 1133 at 230 C., 2.16 kg load of the heterophasic propylene copolymer (HECO2) is in the range of 0.1 to 5.5 g/10 min.

9. Moulded article comprising the polypropylene composition (C) according to claim 1.

10. Moulded article according to claim 9, wherein the article is an automotive article.

11. Moulded article of claim 9, wherein the polypropylene composition (C) enhances paint adhesion of the moulded article.

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) Copolymer Microstructure and Comonomer Content is determined by quantitative nuclear-magnetic resonance (NMR) spectroscopy. Quantitative .sup.13C {.sup.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 .sup.1H and .sup.13C respectively. All spectra were recorded using a .sup.13C optimised 10 mm extended temperature probehead at 125 C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was dissolved in 3 ml of 1,2-tetrachloroethane-d.sub.2 (TCE-d.sub.2) along with chromium-(III)-acetylacetonate (Cr(acac).sub.3) resulting in a 65 mM solution of relaxation agent in solvent as described in G. Singh, A. Kothari, V. Gupta, Polymer Testing 2009, 28(5), 475.

(4) To ensure a homogenous solution, after initial sample preparation in a heat block, the NMR tube was further heated in a rotatory oven for at least 1 hour. Upon insertion into the magnet the tube was spun at 10 Hz. This setup was chosen primarily for the high resolution and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme as described in Z. Zhou, R. Kuemmerle, X. Qiu, D. Redwine, R. Cong, A. Taha, D. Baugh, B. Winniford, J. Mag. Reson. 187 (2007) 225 and V. Busico, P. Carbonniere, R. Cipullo, C. Pellecchia, J. Severn, G. Talarico, Macromol. Rapid Commun. 2007, 28, 1128. A total of 6144 (6 k) transients were acquired per spectra. Quantitative .sup.13C {H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. With characteristic signals corresponding to 2,1 erythro regio defects observed (as described in L. Resconi, L. Cavallo, A. Fait, F. Piemontesi, Chem. Rev. 2000, 100 (4), 1253, in Cheng, H. N., Macromolecules 1984, 17, 1950, and in W-J. Wang and S. Zhu, Macromolecules 2000, 33 1157) the correction for the influence of the regio defects on determined properties was required. Characteristic signals corresponding to other types of regio defects were not observed.

(5) 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.

(6) 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 .sup.13C {.sup.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.

(7) The mole percent comonomer incorporation was calculated from the mole fraction.

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

(9) Calculation of comonomer content of the elastomeric propylene copolymer rubber (EPR1):

(10) $\begin{array}{cc}\frac{\mathrm{Cx}\left(\mathrm{HECO}1\right)-w\left(\mathrm{PM}1\right)\mathrm{Cx}\left(\mathrm{PM}1\right)}{w\left(\mathrm{EPR}1\right)}=\mathrm{Cx}\left(\mathrm{EPR}1\right)& \left(\mathrm{III}\right)\end{array}$
wherein w (PM1) is the weight fraction [in wt.-%] of the (semi)crystalline polypropylene matrix (PM1), i.e. the polymer produced in the loop reactor and the first gas phase reactor (LR+GPR1), w (EPR1) is the weight fraction [in wt.-%] of elastomeric propylene copolymer rubber (EPR1), i.e. the polymer produced in the second gas phase reactor (GPR2), C.sub.x (HECO1) is the comonomer content [in mol %] of the heterophasic propylene copolymer (HECO1), i.e. the polymer produced in the loop reactor, the first gas phase reactor and the second gas phase reactor (LR+GPR1+GPR2), C.sub.x (PM1) is the comonomer content [in mol %] of the (semi)crystalline polypropylene matrix (PM1), i.e. polymer produced in the loop reactor and the first gas phase reactor (LR+GPR1), C.sub.x (EPR1) is the calculated comonomer content [in mol %] of the second propylene copolymer fraction.

(11) Calculation of comonomer content of the elastomeric propylene copolymer rubber (EPR2):

(12) $\begin{array}{cc}\frac{\mathrm{Cx}\left(\mathrm{HECO}2\right)-w\left(\mathrm{PM}2\right)\mathrm{Cx}\left(\mathrm{PM}2\right)}{w\left(\mathrm{EPR}2\right)}=\mathrm{Cx}\left(\mathrm{EPR}2\right)& \left(\mathrm{IV}\right)\end{array}$
wherein w (PM2) is the weight fraction [in wt.-%] of the (semi)crystalline polypropylene matrix (PM2), i.e. the polymer produced in the loop reactor (LR), w (EPR2) is the weight fraction [in wt.-%] of elastomeric propylene copolymer rubber (EPR2), i.e. the polymer produced in the gas phase reactor (GPR), C.sub.x (HECO2) is the comonomer content [in mol %] of the heterophasic propylene copolymer (HECO2), i.e. the polymer produced in the loop reactor and the gas phase reactor (LR+GPR), C.sub.x (PM2) is the comonomer content [in mol %] of the (semi)crystalline polypropylene matrix (PM2), i.e. polymer produced in the loop reactor (LR), C.sub.x (EPR1) is the calculated comonomer content [in mol %] of the second propylene copolymer fraction.

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

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

(15) Xylene Cold Soluble (XCS) fraction is determined at 25 C. according ISO 16152; first edition; 2005-07-01. The part which remains insoluble is the xylene cold insoluble (XCI) fraction.

(16) 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).

(17) 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).

(18) 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.

(19) Charpy Notched Impact Strength (CNIS) is measured according to ISO 179-1/leA/DIN 53453 at 23 C., 20 C. and 30 C., using injection molded bar test specimens of 80104 mm.sup.3 prepared in accordance with ISO 294-1:1996.

(20) Adhesion is characterized as the resistance of the pre-fabricated scratch template to pressure-water jetting according to DIN 55662 (Method C).

(21) Injection moulded sample plates (150 mm80 mm2 mm) were cleaned with a mixture of isopropanol and water (1:1). Subsequently the surface was activated via flaming where a burner with a speed of 600 mm/s spreads a mixture of propane and air in a ratio of 1:23 with a flow rate of 150 l/h on the polymer substrate. Afterwards, the polymer substrate was coated with 2 layers of black paint, i.e. a base coat (Black BMW 668) and a clear coat (BMW 68895). The step of flaming was performed two times.

(22) A steam of hot water with temperature T was directed for time t at distance d under angle to the surface of the test panel. Pressure of the water jet results from the water flow rate and is determined by the type of nozzle installed at the end of the water pipe.

(23) The following parameters were used:

(24) T (water)=60 C.; t=60 s; d=130 mm, =90, water flow rate 11.3 l/min, nozzle type=MPEG 2506.

(25) The adhesion was assessed by quantifying the failed or delaminated painted area per test line. For each example 5 panels (150 mm80 mm2 mm) have been tested. The panels were produced by injection moulding with 240 C. melt temperature and 50 C. mold temperature. The flow front velocity was 100 mm/s. On each panel certain lines were used to assess the paintability failure in [mm.sup.2]. For this purpose, an image of the test point before and after steam jet exposure was taken. Then the delaminated area was calculated with an image processing software. The average failed area for 5 test lines on 5 test specimens (i.e. in total the average of 25 test points) was reported as average failed area.

2. Examples

(26) The polypropylene composition (C) of the inventive example (IE1) is prepared from melt blending heterophasic propylene copolymer (HECO1), heterophasic propylene copolymer (HECO2), filler (F) and additives (AD).

(27) Preparation of HECO1:

(28) Catalyst Preparation

(29) First, 0.1 mol of MgCl.sub.23 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 C. and 300 ml of cold TiCl were added while maintaining the temperature at said level. Then, the temperature of the slurry was increased slowly to 20 C. 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 C. over a period of 90 minutes and subsequently the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl were added and the temperature was kept at 135 C. for 120 minutes. After this, the catalyst was filtered from the liquid and washed six times with 300 ml heptane at 80 C. Then, the solid catalyst component was filtered and dried. Catalyst and its preparation concept is described in general e.g. in patent publications EP 491566, EP 591224 and EP 586390.

(30) The catalyst was further modified (VCH modification of the catalyst). 52 ml of mineral oil (Paraffinum Liquidum PL68) was added to a 125 ml stainless steel reactor followed by 1.17 g of triethyl aluminium (TEAL) and 0.73 g of dicyclopentyl dimethoxy silane (D-donor) under inert conditions at room temperature. After 10 minutes, 5.0 g of the catalyst prepared above (Ti content 1.8 wt.-%) was added, and after additional 20 minutes 5.0 g of vinylcyclohexane (VCH) was added. The temperature was increased to 65 C. over a period of 30 minutes and was kept there for 20 hours. The respective processes are described in EP 1 028 984, EP 1 183 307 and EP 591 224.

(31) Polymerization

(32) The preparation of the heterophasic propylene copolymer (HECO1) is summarized in Table 1a. The properties of the heterophasic propylene copolymer (HECO1) are summarized in Table 1b

(33) TABLE-US-00001 TABLE 1a Polymerization conditions of the heterophasic propylene copolymer (HECO1) HECO1 Donor DCPDMS Cocatalyst TEAL Co/ED [mol/mol] 7.3 Co/TC [mol/mol] 220 Prepolymerization Residence time [h] 0.08 Temperature [ C.] 30 Matrix (PM1) Loop Reactor (LR) Split [wt.-%]# 39 TEMP [ C.] 72 PRE [kPa] 5633 RES [h] 0.6 H2/C3 [mol/kmol] 14.8 MFR [g/10 min] 55 Matrix (PM1) 1st Gas Phase Reactor (GPR1) Split [wt.-%]# 26 TEMP [ C.] 80 PRE [kPa] 2231 RES [h] 0.75 H2/C3 [mol/kmol] 150 MFR2 [g/10 min] 55 Elastomer (EPR1) 2nd Gas Phase Reactor (GPR2) Split [wt.-%]# 20 TEMP [ C.] 70 PRE [kPa] 2291 RES [h] 0.6 H2/C2 ratio [mol/kmol] 116 C2/C3 ratio [mol/kmol] 584 C2 [mol %] 12.2 MFR [g/10 min] 20 XCS wt % 20 Elastomer (EPR1) 3rd Gas Phase Reactor (GPR3) Split [wt.-%]# 15 Residence time [h] 0.6 Temperature [ C.] 85 Pressure [kPa] 1421 C2/C3 ratio [mol/kmol] 585.2 H2/C2 ratio [mol/kmol] 92.7 MFR [g/10 min] 11 split [wt %]# 15 #wt.-% Based on the weight of the heterophasic propylene copolymer (HECO1) DCPDMS Dicyclopentyl dimethoxy silane TEAL Triethylaluminium Co/ED Molar ratio of cocatalyst to external donor in the catalyst Co/TC Molar ratio of cocatalyst to titanium compound MFR Melt flow rate at 230 C. TEMP Temperature PRES Pressure RES Residence time H2/C3 Molar ratio of hydrogen to propylene C2/C3 Molar ratio of ethylene to propylene H2/C2 Molar ratio of hydrogen to ethylene

(34) TABLE-US-00002 TABLE 1b Properties of the heterophasic propylene copolymer (HECO1) Example HECO1 XCS [wt.-%]# 32 IV (XCS) [dl/g] 3.1 C2 (XCS) [mol %] 48 MFR2 [g/10 min] 11 C2 [mol %] 18.5 FM [MPa] 1050 CNIS (20) [kJ/m2] 8.5 #wt.-% Based on the weight of the heterophasic propylene copolymer (HECO1) XCS Xylene cold soluble fraction IV (XCS) Intrinsic viscosity of the xylene cold soluble fraction C2 (XCS) Ethylene content of the xylene cold soluble fraction MFR2 Melt flow rate at 230 C. C2 Ethylene content FM Felxural modulus CNIS (20) Charpy notched impact strength at 20 C.

(35) The propylene copolymer (HECO1) was blended with the 0.05 wt.-% calcium stearate and 0.20 wt.-% Irganox B225FF, based on the weight of the heterophasic propylene copolymer (HECO1), using a twin-screw extruder TSE16TC of Thermo Electron Company GmbH. The calcium stearate and Irganox B225FF are standard antioxidants agents used for stabilizing polymer powders.

(36) Preparation of HECO2:

(37) The HECO2 was prepared in a 21.3 l autoclave equipped with control valves for dosing the reactor with monomers, hydrogen and for flashing. The dosage of monomers and hydrogen into the reactor was monitored by flow controllers and also by monitoring the mass of their respective reservoirs. The temperature of the reactors was controlled via cooling/heating of water in the double jacket around the reactors including sensors in both the top and bottom of the reactor. Helical stirrers with magnetic coupling were used for effective mixing inside the reactor and the stirring rates could be varied during the course of the reaction.

(38) Catalyst Preparation

(39) Used chemicals:

(40) 20% solution in toluene of butyl ethyl magnesium (Mg(Bu)(Et), BEM), provided by Chemtura

(41) 2-ethylhexanol, provided by Amphochem

(42) 3-Butoxy-2-propanol(DOWANOL PnB), provided by Dow

(43) Bis(2-ethylhexyl)citraconate, provided by SynphaBase

(44) TiCl.sub.4, provided by Millenium Chemicals

(45) Toluene, provided by Aspokem

(46) Viscoplex 1-254, provided by Evonik

(47) Heptane, provided by Chevron

(48) Preparation of a Mg Alkoxy Compound:

(49) Mg alkoxide solution was prepared by adding, with stirring at 70 rpm, into 11 kg of a 20 wt.-% solution of butyl ethyl magnesium (Mg(Bu)(Et)) in toluene, a mixture of 4.7 kg of 2-ethylhexanol and 1.2 kg of butoxypropanol in a 20 l stainless steel reactor. During the addition the reactor contents were maintained below 45 C. After the addition was completed, stirring at 70 rpm of the reaction mixture was continued at 60 C. for 30 minutes. After cooling to room temperature 2.3 kg g of the donor bis(2-ethylhexyl)citraconate was added to the Mg-alkoxide solution keeping temperature below 25 C.

(50) Mixing was continued for 15 minutes under stirring at 70 rpm.

(51) Preparation of Solid Catalyst Component:

(52) 20.3 kg of TiCl.sub.4 and 1.1 kg of toluene were added into a 20 l stainless steel reactor. Under stirring at 350 rpm and keeping the temperature at 0 C., 14.5 kg of the above Mg alkoxy compound was added over a period of 1.5 hours. 1.7 l of Viscoplex 1-254 and 7.5 kg of heptane were added and after 1 hour mixing at 0 C., the temperature of the formed emulsion was raised to 90 C. over a period of 1 hour. After 30 minutes mixing was stopped catalyst droplets were solidified and the formed catalyst particles were allowed to settle. After settling for 1 hour, the supernatant liquid was siphoned away. Then the catalyst particles were washed with 45 kg of toluene at 90 C. for 20 minutes followed by two heptane washes (30 kg, 15 min). During the first heptane wash the temperature was decreased to 50 C. and during the second wash to room temperature.

(53) Polymerization

(54) Prepolymerization:

(55) The reactor is initially purged with propylene and then filled with 5930 g ofpropylene and 3 litres of hydrogen for the prepolymerization. The catalyst as defined above (a suspension in a mineral oil) was mixed with a solution of TEAl and D-donor at a TEAl/Ti ratio of 250 mol/mol and a TEAl/Donor ratio of 10 mol/mol for 5 minutes before being added to the reactor. The catalyst loading vessel is then flushed with 250 g propylene to ensure all of the catalyst mixture is added to the reactor. The reactor then undergoes prepolymerization at 30 C. for 6 minutes while stirring at 350 rpm.

(56) Matrix (PM2) Bulk Slurry Reactor (SR):

(57) Subsequently, the reactor is heated up to 80 C. to initiate bulk conditions. While in transition, the desired amount of hydrogen is added to the reactor via a flow controller. Hydrogen is always added batchwise and not continuously during the reaction. Once the desired reactor conditions are reached, the reactor is held at a constant pressure by dosing with propylene. This transition time to reach the bulk conditions was 18 minutes. After the specified bulk residence time, the reactor is purged to 1.5 bar with a stirring speed of 100 rpm. Residual gases are removed from the reactor by treating the reactor with several nitrogen/vacuum cycles to continue to elastomer gas phase step.

(58) Elastomer (EPR2) GPR:

(59) Once the desired purge pressure of 1.5 bar was achieved, the transition to the elastomer gas phase reactor (GPR) began. The stirring rate of the reactor was increased to 200 rpm and the reactor was dosed with propylene and ethylene as the temperature and pressure were increased to the desired levels. The transition time between bulk conditions (SR) and the elastomer gas phase reactor (GPR) was 5 minutes. The comonomers were added to maintain a desired gas ratio. Once the reactor reached the desired temperature, the pressure was held constant at the desired level by dosing with ethylene and propylene at the appropriate gas ratio. The amount of polymer being produced could be monitored by measuring the amount of propylene and ethylene added during the course of the reaction. After a desired split level was reached, the reactor followed the termination procedure outlined below.

(60) Reaction Termination:

(61) After the reaction is completed the stirring speed is reduced to 100 rpm and the gas mixture purged from the reactor to 0 barg. Residual gases are removed from the reactor by treating the reactor with several nitrogen/vacuum cycles. This cycle involves putting the reactor under vacuum for several minutes, filling up to ambient pressures with nitrogen and then repeating the process several times. The product is then safely removed from the reactor.

(62) The preparation of the heterophasic propylene copolymer (HECO2) is summarized in Table 2a. The properties of the heterophasic propylene copolymer (HECO2) are summarized in Table 2b

(63) TABLE-US-00003 TABLE 2a Polymerization conditions of the heterophasic propylene copolymer (HECO2) HECO2 Donor DCPDMS Cocatalyst TEAL Co/ED [mol/mol] 10 Co/TC [mol/mol] 250 Matrix (PM2) Bulk Slurry Reactor (SR) Split [wt.-%].sup.# 45 TEMP [ C.] 80 PRE [kPa] 5682 RES [h] 1.0 H2/C3 [mol/kmol] 39.7 MFR [g/10 min] 550 XCS.sub.m [wt.-%].sup.## 2.5 Elastomer (EPR2) Gas Phase Reactor (GPR) Split [wt.-%].sup.# 55 TEMP [ C.] 80 PRE [kPa] 1300 RES [h] 3.0 C2/C3 [mol/kmol] 2036 H2/C2 [mol/mol] 0 .sup.#wt.-% Based on the weight of the heterophasic propylene copolymer (HECO2) .sup.##wt.-% Based on the weight of the (semi)crystalline polypropylene matrix (PM1) DCPDMS Dicyclopentyl dimethoxy silane TEAL Triethylaluminium Co/ED Molar ratio of cocatalyst to external donor in the catalyst Co/TC Molar ratio of cocatalyst to titanium compound in the catalyst MFR Melt flow rate at 230 C. XCS.sub.m Xylene cold soluble fraction of the matrix TEMP Temperature PRES Pressure RES Residence time C2/C3 Molar ratio of ethylene to propylene H2/C3 Molar ratio of hydrogen to propylene H2/C2 Molar ratio hydrogen to ethylene

(64) TABLE-US-00004 TABLE 2b Properties of the heterophasic propylene copolymer (HECO2) Example HECO2 XCS [wt.-%].sup.# 29.2 IV (XCS) [dl/g] 9.9 C2 (XCS) [mol %] 67 MFR [g/10 min] 0.47 C2 [wt.-%].sup.# 33.7 .sup.#wt.-% Based on the weight of heterophasic propylene copolymer (HECO2) XCS Xylene cold soluble fraction IV (XCS) Intrinsic viscosity of the xylene cold soluble fraction IV (XCI) Intrinsic viscosity of the xylene cold insoluble fraction C2 (XCS) Ethylene content of the xylene cold soluble fraction MFR Melt flow rate at 230 C. C2 Ethylene content

(65) The polypropylene compositions were prepared by melt blending using a twin-screw extruder TSE16TC. During the compounding the following temperature profile was set: 190, 210, 230, 210 C.

(66) The components and the amounts applied in the preparation of the polypropylene compositions are summarized in Table 3.

(67) TABLE-US-00005 TABLE 3 Preparation of the Polypropylene Compositions (C) of the Examples IE1 IE2 CE1 CE2 HECO1 [wt.-%].sup.# 70 70 70 70 HECO2 [wt.-%].sup.# 15 HECO2 (m) [wt.-%].sup.# 15 HECO3 [wt.-%].sup.# 15 HECO3 (m) [wt.-%].sup.# 15 Filler (F) [wt.-%].sup.# 15 15 15 15 Additive (AD) [wt.-%].sup.## 0.25 0.25 0.25 0.25 .sup.#wt.-% Based on the weight of the propylene compositions (C) .sup.##wt.-% Based on the weight of the heterophasic propylene copolymer (HECO1) HECO2 (m) Heterophasic propylene copolymer described according to Table 2a and Table 2b, which has been modified with 5 wt.-% based on the weight of the heterophasic propylene copolymer (HECO2), of a master batch comprising polypropylene and 1 wt.-% of 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (DHBP) based on the weight of the masterbatch. HECO2 (m) has a melt flow rate MFR.sub.2 (230 C.) of 5 g/10 min. The properties of HECO2(m) are described in Table 4. HECO3 Commercial heterophasic propylene copolymer ED007HP of Borealis having a melt flow rate MFR.sub.2 (230 C.) of 7 g/10 min. HECO3 (m) Commercial heterophasic propylene copolymer ED007HP of Borealis, which has been modified with 0.5 wt.-%, based on the weight of the heterophasic propylene copolymer (HECO3), of a master batch comprising polypropylene and 1 wt.-% (2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (DHBP), based on the weight of the masterbatch. HECO3 (m) has a melt flow rate MFR.sub.2 (230 C.) of 10 g/10 min. The properties of HECO3(m) are described in Table 5 Filler (F) Commercial Talc Steamic T1 CA by Luzenac having a D.sub.50 (Sedigraph 5100) of 1.81 m and D.sub.95 (Sedigraph 5100) of 6.2 m. Additives (AD) Penthaerythtrityl-tetrakis(3-(3,5-di-tert. Butyl-4-hydroxyphenyl)-propionate (Irganox B225FF) 0.20 wt. % and Calciumstearate by Faci, 0.05 wt.-%.

(68) TABLE-US-00006 TABLE 4 Properties of the modified heterophasic propylene copolymer (HECO2(m)) Example HECO2m XCS [wt.-%].sup.# 35.6 IV (XCS) [dl/g] 4.35 C2 (XCS) [mol %] 73 MFR [g/10 min] 5.0 C2 [wt.-%].sup.# 33 FM [MPa] 500 CNIS (23) [kJ/m.sup.2] 15.5 .sup.#wt.-% Based on the weight of heterophasic propylene copolymer (HECO2) XCS Xylene cold soluble fraction IV (XCS) Intrinsic viscosity of the xylene cold soluble fraction IV (XCI) Intrinsic viscosity of the xylene cold insoluble fraction C2 (XCS) Ethylene content of the xylene cold soluble fraction MFR Melt flow rate at 230 C. C2 Ethylene content FM Felxural modulus CNIS (23) Charpy notched impact strength at +23 C. CNIS (20) Charpy notched impact strength at 20 C.

(69) TABLE-US-00007 TABLE 5 Properties of the modified heterophasic propylene copolymer (HECO3(m)) Example HECO3m XCS [wt.-%].sup.# 23 IV (XCS) [dl/g] 4.7 C2 (XCS) [mol %] 36.2 MFR [g/10 min] 10.0 C2 [wt.-%].sup.# 17.8 FM [MPa] 1059 CNIS (23) [kJ/m.sup.2] 55 CNIS (20) [kJ/m.sup.2] 7.9 .sup.#wt.-% ased on the weight of heterophasic propylene copolymer (HECO2) XCS Xylene cold soluble fraction IV (XCS) Intrinsic viscosity of the xylene cold soluble fraction IV (XCI) Intrinsic viscosity of the xylene cold insoluble fraction C2 (XCS) Ethylene content of the xylene cold soluble fraction MFR Melt flow rate at 230 C. C2 Ethylene content FM Felxural modulus CNIS (23) Charpy notched impact strength at +23 C. CNIS (20) Charpy notched impact strength at 20 C.

(70) TABLE-US-00008 TABLE 5 Properties of the Examples IE1 IE2 CE3 CE4 MFR.sub.2 [g/10 min] 7 5 10 10 C2 [mol %] 24.1 23.4 17.9 17.8 XCS [wt.-%].sup.# 26 27.7 25 25 C2(XCS) [mol %] 54.7 54.3 48.5 47.9 IV(XCS) [dl/g] 4.2 3.3 3.6 3.4 FM [MPa] 1549 1557 1728 1711 CNIS(23) [kJ/m.sup.2] 57 48 41 42 CNIS(20) [kJ/m.sup.2] 10 9 6.5 6.7 PFA (1:23) mm.sup.2 0 0 0.3 1 0.7 3 L1FA mm 0 0 0 0 0 0 2.2 5 L2FA mm 0 0 0 0 0.8 2 0 0 L3FA mm 0 0 0 0 0 0 0 0 .sup.#wt.-% Based on the weight of polypropylene composition (C) MFR Melt flow rate at 230 C. C2 Ethylene content XCS Xylene cold soluble fraction C2 (XCS) Ethylene content of the xylene cold soluble fraction IV (XCS) Intrinsic viscosity of the xylene cold soluble fraction FM Felxural modulus CNIS(23) Charpy notched impact strength at +23 C. CNIS(20) Charpy notched impact strength at 20 C. PFA Painted Failed Area L1FA Line 1 failed area L2FA Line 2 failed area L3FA Line 3 failed area