Propylene composition with improved impact resistance at low temperature

Abstract

Polypropylene composition comprising comonomer units derived from ethylene in an amount of from 9.0 to 52.0 mol-% and comonomer units derived from a higher a-olefin in an amount of from 0.4 to 3.0 mol-%, wherein said polypropylene composition has an amount of xylene cold solubles of at least 30 wt.-%, wherein further the xylene cold soluble fraction has an ethylene content of from 20.0 to 80.0 mol-% and a higher a-olefin content from 0.1 to 1.5 mol-%.

Claims

1. A polypropylene composition comprising comonomer units derived from ethylene in an amount of from 9.0 to 52.0 mol-% and comonomer units derived from at least one C.sub.5-12 -olefin in an amount of from 0.4 to 3.0 mol-%, wherein the polypropylene composition (a) has an amount of xylene cold solubles (XCS) of at least 30 wt.-%, (b) fulfills in-equation (I)
IV(XCS)IV(tot)0.30(I) wherein IV(XCS) is the intrinsic viscosity (IV) of the xylene cold soluble (XCS) fraction of the polypropylene composition, and IV(tot) is the intrinsic viscosity (IV) of the polypropylene composition, and (c) is a heterophasic propylene copolymer (HECO) comprising a propylene copolymer (C) and an elastomeric copolymer (E), wherein the propylene copolymer (C) is a propylene copolymer of units derived from propylene and at least one C.sub.5-12 -olefin and the elastomeric copolymer (E) is a terpolymer (T) of units derived from propylene ethylene and C.sub.5-12 -olefin.

2. The polypropylene composition according to claim 1, wherein the xylene cold soluble (XCS) fraction has an amount (a) of ethylene-derived comonomer units of from 20.0 to 80.0 mol-%; and/or (b) of C.sub.5-12 -olefin-derived comonomer units of from 0.1 to 1.5 mol-%.

3. A polypropylene composition comprising comonomer units derived from ethylene in an amount of from 9.0 to 52.0 mol-% and comonomer units derived from at least one C.sub.5-12 -olefin in an amount of from 0.4 to 3.0 mol-%, wherein the polypropylene composition has an amount of xylene cold solubles (XCS) of at least 30 wt.-%, wherein further the xylene cold solubles (XCS) of the polypropylene composition has an amount of (a) of ethylene-derived comonomer units of from 20.0 to 80.0 mol-%; and/or (b) of C.sub.5-12 -olefin-derived comonomer units of from 0.1 to 1.5 mol-%.

4. The polypropylene composition according to claim 3, wherein the polypropylene composition fulfills in-equation (I)
IV(XCS)IV(tot)0.30(I) wherein IV(XCS) is the intrinsic viscosity (IV) of the xylene cold soluble (XCS) fraction of the polypropylene composition and IV(tot) is the intrinsic viscosity (IV) of the polypropylene composition.

5. The polypropylene composition according to claim 1, wherein (a) the amount of 20 wt-% of ethylene-derived comonomer units in the xylene cold soluble (XCS) fraction of the polypropylene composition is excluded; and/or (b) the polypropylene composition fulfills in-equation (II) $\begin{array}{cc}57.0<\frac{\mathrm{XCS}}{\mathrm{CX}\left(\mathrm{XCS}\right)}<300& \left(\mathrm{II}\right)\end{array}$ wherein CX(XCS) is the amount in mol-% of C.sub.5-12 -olefin-derived comonomer units in the xylene cold soluble (XCS) fraction of the polypropylene composition, XCS is the amount in wt.-% of xylene cold soluble (XCS) fraction of the polypropylene composition.

6. The polypropylene composition according to claim 1, wherein (a) the C.sub.5-12 -olefin is 1-hexene or 1-octene; and/or (b) the total amount of comonomer units in the polypropylene composition is from 9.4 to 55.5 mol-%.

7. The polypropylene composition according to claim 1, wherein (a) the intrinsic viscosity (IV) of the xylene cold soluble (XCS) fraction of the polypropylene composition is in the range of 1.5 to 4.0 dl/g; and/or (b) the intrinsic viscosity (IV) of the polypropylene composition is in the range of 1.0 to 3.0 dl/g.

8. The polypropylene composition according to claim 1, wherein the polypropylene composition has a glass transition temperature below 25 C.

9. The polypropylene composition according to claim 1, wherein the propylene copolymer (C) comprises a propylene homopolymer fraction (HF1) and a propylene copolymer fraction (CF1), wherein further the propylene copolymer fraction (CF1) consists of units derived from derived from propylene and at least one C.sub.5-12 -olefin.

10. The polypropylene composition according to claim 1, wherein (a) the terpolymer (T) has a comonomer content in the range of 20.05 to 82.0 mol-%; and/or (b) the weight ratio between the propylene homopolymer fraction (HF1) and the propylene copolymer fraction (CF1) [(HF1)/(CF1)] is 75/25 to 30/70; and/or (c) the weight ratio between the propylene copolymer (C) and the elastomeric copolymer (E) [(C)/(E)] is 75/25 to 40/60.

11. A molded article comprising the polypropylene composition according to claim 1.

12. A process for preparing the polypropylene composition according to claim 1, comprising (i) preparing the propylene homopolymer fraction (HF1) in a first polymerization reactor PR1, (ii) transferring the propylene homopolymer fraction (HF1) obtained in the polymerization reactor (R1) to a polymerization reactor (R2) and preparing the propylene copolymer fraction (CF1) by polymerizing propylene and at least one C.sub.5-12 -olefin in the presence of propylene homopolymer fraction (HF1), thereby obtaining the propylene copolymer (C); and (iii) transferring the propylene copolymer (C) of step (ii) into a polymerization reactor (R3) and preparing the elastomeric copolymer (E) by polymerizing propylene, ethylene and at least one C.sub.5-12 -olefin in the presence of the propylene copolymer (C), thereby obtaining the polypropylene composition.

13. The polypropylene composition according to claim 6, wherein (a) the C.sub.5-12 -olefin is 1-hexene; and/or (b) the total amount of comonomer units are derived from ethylene and at least one C.sub.5-12 -olefin in the polypropylene composition is from 9.4 to 55.5 mol-%.

14. The polypropylene composition according to claim 3, wherein (a) the amount of 20 wt-% of ethylene-derived comonomer units in the xylene cold soluble (XCS) fraction of the polypropylene composition is excluded; and/or (b) the polypropylene composition fulfills in-equation (II) $\begin{array}{cc}57.0<\frac{\mathrm{XCS}}{\mathrm{CX}\left(\mathrm{XCS}\right)}<300& \left(\mathrm{II}\right)\end{array}$ wherein CX(XCS) is the amount in mol-% of C.sub.5-12 -olefin-derived comonomer units in the xylene cold soluble (XCS) fraction of the polypropylene composition, XCS is the amount in wt.-% of xylene cold soluble (XCS) fraction of the polypropylene composition.

15. The polypropylene composition according to claim 3, wherein (a) the C.sub.5-12 -olefin is 1-hexene or 1-octene; and/or (b) the total amount of comonomer units in the polypropylene composition is from 9.4 to 55.5 mol-%.

16. The polypropylene composition according to claim 3, wherein (a) the intrinsic viscosity (IV) of the xylene cold soluble (XCS) fraction of the polypropylene composition is in the range of 1.5 to 4.0 dl/g; and/or (b) the intrinsic viscosity (IV) of the polypropylene composition is in the range of 1.0 to 3.0 dl/g.

17. The polypropylene composition according to claim 3, wherein the polypropylene composition has a glass transition temperature below 25 C.

18. The polypropylene composition according to claim 3, wherein the polypropylene composition is a heterophasic propylene copolymer (HECO) comprising a propylene copolymer (C) and an elastomeric copolymer (E), wherein the propylene copolymer (C) is a propylene copolymer of units derived from propylene and at least one C.sub.5-12 -olefin and the elastomeric copolymer (E) is a terpolymer (T) of units derived from propylene, ethylene and C.sub.5-12 -olefin.

19. The polypropylene composition according to claim 18, wherein the propylene copolymer (C) comprises a propylene homopolymer fraction (HF1) and a propylene copolymer fraction (CF1), wherein further the propylene copolymer fraction (CF1) consists of units derived from derived from propylene and at least one C.sub.5-12 -olefin.

Description

EXAMPLES

1. Measuring Methods

(1) 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. Calculation of comonomer content of the propylene copolymer fraction (CF2):

(2) $\frac{C\left(P1+P2\right)-w\left(P1\right)C\left(P1\right)}{w\left(P2\right)}=C\left(P2\right)$

(3) wherein w(P1) is the weight fraction [in wt.-%] of the propylene copolymer fraction (CF1) based on the weight of the propylene copolymer (C), w(P2) is the weight fraction [in wt.-%] of propylene copolymer fraction (CF2) based on the weight of the propylene copolymer (C), C(P1) is the comonomer content [in mol-%] of the propylene copolymer fraction (CF1), C(P1+P2) is the comonomer content [in mol-%] of the propylene copolymer (C), C(P2) is the calculated comonomer content [in mol-%] of the propylene copolymer fraction (CF2).

(4) Calculation of melt flow rate MFR.sub.2 (230 C.) of the propylene copolymer fraction (CF2):

(5) $\mathrm{MFR}\left(P2\right)={10}^{\left[\frac{\log \left(\mathrm{MFR}\left(P1+P2\right)\right)-w\left(P1\right)\log \left(\mathrm{MFR}\left(P1\right)\right)}{w\left(P2\right)}\right]}$

(6) wherein w(P1) is the weight fraction [in wt.-%] of the propylene copolymer fraction (CF1) based on the weight of the propylene copolymer (C), w(P2) is the weight fraction [in wt.-%] of the propylene copolymer fraction (CF2) based on the weight of the propylene copolymer (C), MFR(P1) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the propylene copolymer fraction (CF1), MFR(P1+P2) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the propylene copolymer (C), MFR(P2) is the calculated melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the propylene copolymer fraction (CF2).

(7) Identical approach is used in case the propylene copolymer (C) consists of a propylene homopolymer fraction (HF1) (wherein (CF1) is replaced by (HF1)) and a propylene copolymer fraction (CF1) (wherein (CF2) is replaced by (CF1)).

(8) Calculation of comonomer content of the elastomeric copolymer (E), e.g. of the terpolymer (T):

(9) $\frac{C\left(P1+P2\right)-w\left(P1\right)C\left(P1\right)}{w\left(P2\right)}=C\left(P2\right)$

(10) wherein w(P1) is the weight fraction [in wt.-%] of the propylene copolymer (C) based on the weight of the polypropylene composition, w(P2) is the weight fraction [in wt.-%] of the elastomeric copolymer (E) based on the weight of the polypropylene composition, C(P1) is the comonomer content [in mol-%] of the propylene copolymer (C), C(P1+P2) is the comonomer content [in mol-%] of the polypropylene composition, C(P2) is the calculated comonomer content [in mol-%] of the elastomeric copolymer (E).

(11) Quantification of Polymer Microstructure by NMR Spectroscopy

(12) Quantitative nuclear-magnetic resonance (NMR) spectroscopy was used to quantify the comonomer content of the polymers.

(13) Quantitative .sup.13C{.sup.1H} NMR spectra recorded in the molten-state using a Bruker Advance III 500 NMR spectrometer operating at 500.13 and 125.76 MHz for .sup.1H and .sup.13C respectively. All spectra were recorded using a .sup.13C optimised 7 mm magic-angle spinning (MAS) probehead at 180 C. using nitrogen gas for all pneumatics. Approximately 200 mg of material was packed into a 7 mm outer diameter zirconia MAS rotor and spun at 4 kHz. This setup was chosen primarily for the high sensitivity needed for rapid identification and accurate quantification {Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382; Parkinson, M., Klimke, K., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2007; 208:2128; Castignolles, P., Graf, R., Parkinson, M., Wilhelm, M., Gaborieau, M., Polymer 2009, 50, 2373}. Standard single-pulse excitation was employed utilising the NOE at short recycle delays {Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004, 37, 813; Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006, 207, 382} and the RS-HEPT decoupling scheme {Filip, X., Tripon, C., Filip, C., J. Mag. Resn. 2005, 176, 239; Griffin, J. M., Tripon, C., Samoson, A., Filip, C., and Brown, S. P., Mag. Res. in Chem. 2007 45, S1, S198}. A total of 1024 (1 k) transients were acquired per spectra.

(14) Quantitative .sup.13C{.sup.1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals. All chemical shifts are internally referenced to the methyl isotactic pentad (mmmm) at 21.85 ppm.

(15) The tacticity distribution was quantified through integration of the methyl region in the .sup.13C{.sup.1H} spectra correcting for any sites not related to the stereo sequences of interest. {Busico, V., Cipullo, R., Prog. Polym. Sci. 2001, 26, 443; Busico, V., Cipullo, R., Monaco, G., Vacatello, M., Segre, A. L., Macromoleucles 1997, 30, 6251}.

(16) The influence of regio defects on the quantification of the tacticity distribution was corrected for by subtraction of representative regio defect integrals from specific integrals of the stereo sequences.

(17) The influence of comonomer on the quantification of the tacticity distribution was corrected for by subtraction of representative comonomer integrals from specific integrals of the stereo sequences.

(18) The isotacticity was determined at the triad level and reported as the percentage of isotactic triad (mm) with respect to all triad sequences:
mm[%]=100*(mm/sum of all triads)

(19) where mr represents the sum of the reversible mr and rm triad sequences.

(20) Characteristic signals indicative of regio defects were observed {Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253}.

(21) The presence of 2,1-erythro regio defects was indicated by the presence of the P and P methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic signals.

(22) The amount of 2,1-erythro regio defects was quantified using the average integral of the P and P sites at 17.7 and 17.2 ppm:
P.sub.21e=0.5*(I.sub.e6+I.sub.e8)

(23) The presence of ethylene incorporated directly after a secondary inserted propene (E21) was indicated by the presence of the S, S and T sites at 34.9, 34.5 and 33.8 ppm and confirmed by other characteristic signals.

(24) The amount ethylene incorporated directly after a secondary inserted propene was quantified using the integral of the T site at 33.8 ppm:
E21=ITT

(25) The total amount of secondary (2,1) inserted propene was quantified as the sum of all units containing secondary inserted propene:
P.sub.21=P.sub.21e+E21

(26) Characteristic signals corresponding to other regio defects were not observed {Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253}.

(27) The total amount of primary (1,2) inserted propene was quantified based on the propene methyl sites between 23.6 and 19.7 ppm with correction for any included sites not related to primary insertion:
P.sub.12=I.sub.CH3+P.sub.21e

(28) The total amount of propene was quantified as the sum of primary (1,2) inserted propene and all regio defects:
Ptotal=P.sub.12+P.sub.21

(29) The mole percent of 2,1-erythro regio defects was quantified with respect to all propene:
[21e]mol %=100*(P.sub.21e/P.sub.total)

(30) Characteristic signals corresponding to the incorporation of 1-hexene were observed and the comonomer fraction calculated as the fraction of 1-hexene in the polymer with respect to all monomer in the polymer:
fHtotal=Htotal/(Etotal+Ptotal+Htotal))

(31) The amount isolated 1-hexene incorporated in PPHPP sequences was quantified using the integral of the B4 sites at 44.1 ppm accounting for the number of reporting sites per comonomer and the presence of consecutively incorporated 1-hexene in PPHHPP sequences:
H=(IB4/2)(HH/2)

(32) The amount consecutively incorporated 1-hexene in PPHHPP sequences was quantified using the integral of the B4B4 site at 41.6 ppm accounting for the number of reporting sites per comonomer:
HH=2*IB4B4

(33) The total 1-hexene content was calculated based on the sum of isolated and consecutively incorporated 1-hexene:
Htotal=H+HH

(34) Characteristic signals corresponding to the incorporation of ethylene were observed and the comonomer fraction calculated as the fraction of ethylene in the polymer with respect to all monomer in the polymer:
fEtotal=Etotal/(Etotal+Ptotal+Htotal)

(35) The amount isolated and non-consecutive ethylene incorporated in PPEPP and PPEPEPP sequences respectively was quantified using the integral of the S sites at 24.5 ppm accounting for the number of reporting sites per comonomer:
E=I.sub.S

(36) The presence of non-consecutive ethylene incorporation in PPEPEPP sequences was indicated by the presence of the T site at 33.1 ppm and confirmed by other characteristic signals.

(37) The amount double consecutively incorporated ethylene in PPEEPP sequences was quantified using the integral of the S site at 27.1 ppm accounting for the number of reporting sites per comonomer:
EE=I.sub.S

(38) The amount triple or longer consecutively incorporated ethylene in PP(E)nPP sequences was quantified using the integral of the S and S sites at 29.6 and 30.1 ppm accounting for the number of reporting sites per comonomer:
EEE=(IS/2)+(IS/4)

(39) The total ethylene content was calculated based on the sum of isolated, consecutively incorporated ethylene and ethylene incorporated directly after a secondary inserted propene:
Etotal=E+EE+EEE+E21

(40) The mole percent comonomer incorporation is calculated from the mole fraction:
H[mol %]=100*fHtotal
E[mol %]=100*fEtotal

(41) The weight percent comonomer incorporation is calculated from the mole fraction:
H[wt %]=100*(fHtotal*84.16)/((fEtotal*28.05)+(fHtotal*84.16)+((1(fEtotal+fHtotal))*42.08))
E[wt %]=100*(fEtotal*28.05)/((fEtotal*28.05)+(fHtotal*84.16)+((1(fEtotal+fHtotal))*42.08))

(42) MFR.sub.2 (230 C.) is measured according to ISO 1133-1 (230 C., 2.16 kg load).

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

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

(45) DSC analysis, melting temperature (T.sub.m) and heat of fusion (H.sub.f), crystallization temperature (T.sub.c) and heat of crystallization (H.sub.c) measured with a TA Instrument Q200 differential scanning calorimetry (DSC) on 5 to 7 mg samples. DSC is run according to ISO 11357/part 3/method C2 in a heat/cool/heat cycle with a scan rate of 10 C./min in the temperature range of 30 to +225 C. Crystallization temperature and heat of crystallization (H.sub.c) are determined from the cooling step, while melting temperature and heat of fusion (H.sub.f) are determined from the second heating step.

(46) The glass transition temperature Tg is determined by dynamic mechanical analysis according to ISO 6721-7. The measurements are done in torsion mode on compression moulded samples (40101 mm.sup.3) between 100 C. and +150 C. with a heating rate of 2 C./min and a frequency of 1 Hz.

(47) Tensile Modulus was measured according to ISO 527-2 (cross head speed=1 mm/min; 23 C.) using injection molded specimens as described in EN ISO 1873-2 (dog bone shape, 4 mm thickness).

(48) The Charpy notched impact strength (Charpy NIS) was measured according to ISO 179 1 eA at 20 C., using injection molded bar test specimens of 80104 mm.sup.3 mm.sup.3 prepared in accordance with ISO 294-1:1996

(49) Brittle-to-Ductile Transition Temperature

(50) The determination of the brittle-to-ductile transition temperature (BDTT) is based on the a(cN) values as determined from Charpy instrumented impact strength according to ISO 179-2:2000 on V-notched specimen with a geometry of 80104 mm3 as required in ISO 179-1 eA.

(51) The a(cN) values are determined in intervals of 3 C. from 40 C. to +41 C. with an impact velocity of 1.5 m/s and plotted over temperature, calculating the BDTT as the average value of the step increase. For a detailed description of the determination of the BDTT reference is made to Grein, C. et al, Impact Modified Isotactic Polypropylene with Controlled Rubber Intrinsic Viscosities: Some New Aspects About Morphology and Fracture, J Appl Polymer Sci, 87 (2003), 1702-1712.

2. Examples

(52) The catalyst has been prepared following the procedure described in WO 2013/007650 A1 for catalyst E2, by adjusting the metallocene and MAO amounts in order to achieve the Al/Zr ratio indicated in table 1. The catalyst has been off-line prepolymerized with propylene, following the procedure described in the above document for catalyst E2P.

(53) TABLE-US-00001 TABLE 1 Catalyst DofP.sup.1 Al/Zr.sup.2 MC.sup.3 cat. Metallocene [g/g] [mol/mol] [wt.-%] Cat MC1* 1.8 267 1.69 *rac-anti-Me.sub.2Si(2-Me-4-(p-tBuPh)-Ind)(2-Me-4-Ph-5-OMe-6-tBu-Ind)ZrCl.sub.2 .sup.1Degree of off-line pre-polymerisation .sup.2Al/Zr molar ratio in catalyst .sup.3MC content of off-line prepolymerised catalyst

Comparative Example CE1

Step 1: Prepolymerization+Bulk

(54) A stirred autoclave (double helix stirrer) with a volume of 21.2 dm.sup.3 containing 0.2 bar-g propylene is filled with additional 3.97 kg propylene. After adding 0.73 mmol triethylaluminium (Aldrich, 1 molar solution in n-hexane) using a stream of 250 g propylene, the solution is stirred at 20 C. and 250 rpm for 20 min, then the reactor is brought up to the set prepolymerization temperature (HB-Therm) and the catalyst is injected as described in the following. The solid, pre-polymerized catalyst (amount as listed in Table 2) is loaded into a 5-mL stainless steel vial inside the glovebox, the vial is attached to the autoclave, then a second 5-mL vial containing 4 ml n-hexane and pressurized with 10 bars of N2 is added on top, the valve between the two vials is opened and the solid catalyst is contacted with hexane under N2 pressure for 2 s, then flushed into the reactor with 250 g propylene. Stirring speed is increased to 250 rpm and prepolymerisation is run for the set time. At the end of the prepolymerization step the stirring speed is increased to 250 rpm and the reactor temperature raised to 80 C. When the internal reactor temperature reaches 71 C., the desired H2 amount is added with a defined flow via thermal mass flow controller. The reactor temperature is held constant throughout the polymerization time. The polymerization time is measured starting when the temperature is 2 C. below the set polymerization temperature.

Step 2: Gas Phase

(55) After the bulk step is finished, the stirrer speed is reduced to 50 rpm and the reactor pressure reduced to 24.5 bar-g by venting. Afterwards the stirrer speed is set to 180 rpm, the reactor temperature to 85 C. and the chosen amount of 1-hexene is dosed via mass flow controllers (MFC) with a flow of 15 g/min. Then the reactor P and T are held constant by feeding via MFC a given ratio of C3/C6 at 25 bar-g and 85 C. for the time needed to reach the target split. Then the reaction is stopped by setting the stirrer speed to 20 rpm, cooling the reactor down to 30 C., flashing the volatile components.

(56) After flushing the reactor twice with N2 and one vacuum/N2 cycle, the product is taken out and dried overnight in a hood. 100 g of the polymer is additivated with 0.2 wt % Ionol and 0.1 wt % PEPQ (dissolved in acetone) and dried also overnight in a hood+2 hours in a vacuum drying oven at 60 C.

Comparative Examples CE2, CE3 and Inventive Examples IE1, IE2, IE3, IE4

Step 1: Prepoly+Bulk See CE1

Step 2: Gas Phase 1

(57) After the bulk step is finished, the stirrer speed is reduced to 50 rpm and the reactor pressure reduced to 24.5 bar-g by venting. Afterwards the stirrer speed is set to 180 rpm, the reactor temperature to 85 C. and the chosen amount of 1-hexene is dosed via MFC with a flow of 15 g/min. Then the reactor P and T are held constant by feeding via MFC a given ratio of C3/C6 at 25 bar-g and 85 C. for the time required to reach the target split.

Step 3: Gas Phase 2

(58) After the bulk+gas step 1 has finished, the temperature control device was set to 70 C. and the stirrer speed is reduced to 50 rpm. The reactor pressure is then reduced to 0.3 bar-g by venting, the stirrer speed is adjusted to 180 rpm and the reactor T to the target value. Then the reactor filling is started by feeding a defined ratio of C3/C2 monomer gas. This ratio depends on the relative comonomer reactivity ratio (R C2/C3) of the given catalyst system and the desired copolymer composition. The speed of the reactor filling during the transition is limited by the max. flow of the gas flow controllers. When the reactor temperature reaches 1 below the target temperature and the pressure has reached the desired value, the composition of the dosed C3/C2 mixture is changed to match the desired polymer composition and both temperature and pressure are held constant as long as the amount of C3/C2 gas mixture required to reach the target split of rubber to matrix has been consumed. The reaction is stopped by setting the stirrer speed to 20 rpm, cooling the reactor to 30 C. and flashing the volatile components.

(59) After flushing the reactor twice with N2 and one vacuum/N2 cycle, the product is taken out and dried overnight in a hood. 100 g of the polymer is additivated with 0.2 wt % Ionol and 0.1 wt % PEPQ (dissolved in acetone) and dried also overnight in a hood+2 hours in a vacuum drying oven at 60 C.

(60) Specific polymerisation process parameters for the comparative and inventive examples are shown in table 2a and 2b.

(61) TABLE-US-00002 TABLE 2a Polymerization and Properties of the comparative examples Parameter unit CE1 CE2 CE3 Prepolymerisation temperature [ C.] 20 20 20 residence time [min] 10 10 10 prepolymerized cat. amount [mg] 138 138 138 Loop temperature [ C.] 80 80 80 pressure [bar-g] 55 55 55 residence time [min] 30 30 30 C3 total [g] 4429 4423 4429 H2 total [nl] 2.8 2.8 1.8 yield [g] 515 565 597 C2 [mol-%] 0 0 0 C6 [mol-%] 0 0 0 Split [wt.-%] 52 32 34 GPR1 temperature [ C.] 85 85 85 pressure [bar-g] 25 25 25 residence time [min] 62 51 60 H2 feed [nl] 0 0 0 C3 feed during transition [g] 1050 1050 1050 C3 feed during polymerization [g] 430 430 430 C6 feed during transition [g] 49 50 50 C6 feed during polymerization [g] 38 40 38 yield [g] 468 470 468 C2 total [mol-%] 0 0 0 C6 total [mol-%] 2.3 1.1 1.2 C6* [mol-%] 4.6 3.7 4.4 XCS [wt.-%] 26.6 27.1 28 MFR [g/10 min] 28.5 IV [dl/g] 1.5 Split [wt.-%] 48 27 26 GPR2 temperature [ C.] 70 70 pressure [bar-g] 19.6 19.7 residence time [min] 63 46 H2 feed [nl] 0 0 C3 feed during transition [g] 483 483 C3 feed during polymerization [g] 648 640 C2 feed during transition [g] 155 155 C2 feed during polymerization [g] 71 70 yield [g] 719 710 C2 [mol-%] 8 8 C6 [mol-%] 1.1 1.2 C2 [mol-%] 19.5 20.0 C6** [mol-%] 0.24 0.15 XCS [wt.-%] 57.0 56.8 C2 in XCS [mol-%] 13.3 13.9 C6 in XCS [mol-%] 5.9 1.2 0.7 MFR [g/10 min] 7.7 5.5 IV [dl/g] 1.85 2.04 IV of XCS [dl/g] 2.3 2.2 Split [wt.-%] 41 40

(62) TABLE-US-00003 TABLE 2b Polymerization and Properties of the inventive examples Parameter unit IE1 IE2 IE3 IE4 Prepolymerisation temperature [ C.] 20 20 20 20 residence time [min] 10 10 10 10 prepolymerized cat. [mg] 142 182 139 140 amount Loop temperature [ C.] 80 80 80 80 pressure [bar-g] 55 55 55 55 residence time [min] 30 30 30 36.5 C3 total [g] 4425 4436 4429 4429 H2 total [nl] 2.8 2.8 1.8 1.8 yield [g] 531 772 598 792 C2 [mol-%] 0 0 0 0 C6 [mol-%] 0 0 0 0 Split [wt.-%] 31 37 38 39 GPR1 temperature [ C.] 85 85 85 85 pressure [bar-g] 25 25 25 25 residence time [min] 62 51 60 69 H2 feed [nl] 0 0 0 0 C3 feed during [g] 1050 1000 1050 1050 transition C3 feed during [g] 440 500 224 336 polymerization C6 feed during [g] 50 50 50 48 transition C6 feed during [g] 36 45 21 29 polymerization yield [g] 476 545 245 365 C2 total [mol-%] 0 0 0 0 C6 total [mol-%] 1.7 1.6 1.3 0.9 C6* [mol-%] 3.5 3.9 4.3 2.8 XCS [wt.-%] 32.7 23.8 15.6 16.0 Split [wt.-%] 28 26 16 18 GPR2 temperature [ C.] 70 70 70 70 pressure [bar-g] 20 19.8 20 20 residence time [min] 55 68 131 123 H2 feed [nl] 0 0 0 0 C3 feed during [g] 321 227 328 252 transition C3 feed during [g] 568 549 569 625 polymerization C2 feed during [g] 238 285 244 271 transition C2 feed during [g] 139 234 142 268 polymerization yield [g] 707 783 711 893 C2 total [mol-%] 15.7 19.0 15.0 19.7 C6 total [mol-%] 1.1 1.1 0.8 0.6 C2 [mol-%] 38.3 51.4 32.6 45.8 C6** [mol-%] 0.24 0.25 0.21 0.20 XCS [wt.-%] 60.3 52.0 54.4 52.1 C2 in XCS [mol-%] 25.7 36.3 26.6 36.1 C6 in XCS [mol-%] 0.9 0.9 0.8 0.5 MFR [g/10 min] 15.5 15.6 4.9 6.1 IV [dl/g] 1.61 1.72 1.94 1.85 IV of XCS [dl/g] 1.7 1.8 2.0 1.6 Split [wt.-%] 41 37 46 43 is the C2 content of the polymer produced in the GPR2 *is the C6 content of the polymer produced in the GPR1 **is the C6 content of the polymer produced in the GPR2

(63) TABLE-US-00004 TABLE 3 Properties of the examples Parameter unit CE1 CE2 CE3 IE1 IE2 IE3 IE4 Tg [ C.] [ C.] 16 16.6 35.2 44.1 34.9 41.9 NIS [kJ/m.sup.2] 1.1 1.5 1.6 80 51 80 81 (19 C.) DBTT [ C.] 51 2 4 26 31 29 35 T.sub.m [ C.] 147 142 147 142 143 145 144 T.sub.c [ C.] 104 107 104 106 106 107 109 TM [MPa] 767 363 327 264 402 292 375 T.sub.g glass transition temperature of the amorphous phase NIS (19 C.) Notched Impact Strength at 19 C. DBTT Ductile to brittle transition temperature T.sub.m melting temperature T.sub.c crystallization temperature TM Tensile Modulus