Soft heterophasic random propylene copolymer with improved clarity

Abstract

The invention is related to a new soft heterophasic random propylene copolymer with improved optical properties, as well as the process by which the heterophasic random propylene copolymer is produced.

Claims

1. A heterophasic propylene copolymer (RAHECO) having (a) a xylene cold soluble content (XCS) determined according ISO 16152 (25 C.) in the range of 25.0 to 35.0 wt.-%, and (b) a comonomer content in the range of more than 4.5 to 10.0 wt.-%, wherein further (c) the comonomer content of xylene cold soluble (XCS) fraction of the propylene copolymer is in the range of 12.0 to 22.0 wt.-%, (d) the intrinsic viscosity (IV) determined according to DIN ISO 1628/1 (in decalin at 135 C.) of the xylene cold soluble (XCS) fraction of the propylene copolymer is in the range of more than 1.5 to below 3.0 dl/g, and (e) the relative content of isolated to block ethylene sequences (I(E)) of the XCS fraction fulfilling the inequation (I)
I(E)<78 1.97C2+0.015(C2).sup.2(I) wherein C2 is the comonomer content [wt %] of the XCS fraction and wherein the I(E) content is defined by equation (II)
I(E)=fPEP/((fEEE+fPEE+fPEP))100(II) wherein I(E) is the relative content of isolated to block ethylene sequences [in %]; fPEP is the mol fraction of propylene/ethylene/propylene sequences (PEP) in the sample; fPEE is the mol fraction of propylene/ethylene/ethylene sequences (PEE) and of ethylene/ethylene/propylene sequences (EEP) in the sample; fEEE is the mol fraction of ethylene/ethylene/ethylene sequences (EEE) in the sample wherein all sequence concentrations are based on a statistical triad analysis of 13C-NMR data.

2. The heterophasic propylene copolymer (RAHECO) according to claim 1, wherein the xylene cold insoluble (XCI) fraction of the propylene copolymer has one or more of: (a) a polydispersity (Mw/Mn) of more than 4.9 to 10.0, or (b) a comonomer content in the range of 3.0 to 7.0.

3. The heterophasic propylene copolymer (RAHECO) according to claim 1, wherein the total melt flow rate MFR.sub.2 (230 C.) of the heterophasic propylene copolymer (RAHECO) measured according to ISO 1133 is in the range of more than 0.8 to below 2.5 g/10 min.

4. The heterophasic propylene copolymer (RAHECO) according to claim 1, wherein the heterophasic propylene copolymer (RAHECO) comprises one or more of: (a) an -nucleating agent, or (b) a hexane soluble content of below 5.5 wt.-%.

5. The heterophasic propylene copolymer (RAHECO) according to claim 1, wherein the heterophasic propylene copolymer (RAHECO) has a melting temperature Tm determined by differential scanning calorimetry (DSC) of not lower than 140 C.

6. The heterophasic propylene copolymer (RAHECO) according to claim 1, wherein the heterophasic propylene copolymer (RAHECO) comprises a matrix (M) and an elastomeric propylene copolymer (E) dispersed in said matrix (M), wherein (a) said matrix (M) is a random propylene copolymer (R-PP), and (b) the weight ratio between the matrix (M) and the elastomeric propylene copolymer (E) is 60/40 to 95/5.

7. The heterophasic propylene copolymer (RAHECO) according to claim 6, wherein the random propylene copolymer (R-PP) comprises one or more of: (a) a comonomer content in the range of 1.5 to 7.0 wt.-%, or (b) fulfills inequation (III)
Co(total)/Co(RPP)1.3(III) wherein Co (total) is the comonomer content [wt.-%] of the heterophasic propylene copolymer (RAHECO), Co (RPP) is the comonomer content [wt.-%] of the random propylene copolymer (R-PP), or (c) has a xylene cold soluble (XCS) fraction in the range of 8.0 to below 20.0 wt.-%.

8. The heterophasic propylene copolymer (RAHECO) according to claim 6, wherein the elastomeric propylene copolymer (E) has a comonomer content of not higher than 30.0 wt.-%.

9. The heterophasic propylene copolymer (RAHECO) according to claim 1, wherein an extrusion blow molded bottle with wall thickness of 0.3 mm comprising the said heterophasic propylene copolymer (RAHECO) has a clarity determined according to ASTM D1003 of higher than 70.0%.

10. A polymerization process for producing a heterophasic propylene copolymer (RAHECO), comprising the steps of (a) polymerizing in a first reactor (R1) propylene and one or more of ethylene or a C4 to C12 -olefin, obtaining a first random propylene copolymer fraction (R-PP1), (b) transferring the first random propylene copolymer fraction (R-PP1), into a second reactor (R2), (c) polymerizing in said second reactor (R2) in the presence of the first random propylene copolymer fraction (R-PP1), propylene and one or more of ethylene or a C4 to C12 -olefin, obtaining a second random propylene copolymer fraction (R-PP2), the first and second polymer fraction form the random propylene copolymer (R-PP), (d) transferring said random propylene copolymer (R-PP), into a third reactor (R3), (e) polymerizing in said third reactor (R3) in the presence of the random propylene copolymer (R-PP), propylene and one or more of ethylene or a C4 to C12 -olefin, obtaining a third polymer fraction, said third polymer fraction is the elastomeric propylene copolymer (E); the third polymer fraction and the random propylene copolymer (R-PP) form the heterophasic propylene copolymer (RAHECO), and (f) removing the propylene copolymer from the third reactor (R3), wherein the heterophasic propylene copolymer (RAHECO) comprises: (a) a xylene cold soluble content (XCS) determined according ISO 16152 (25 C.) in the range of 25.0 to 35.0 wt.-%, and (b) a comonomer content in the range of more than 4.5 to 10.0 wt.-%, wherein further (c) the comonomer content of xylene cold soluble (XCS) fraction of the propylene copolymer is in the range of 12.0 to 22.0 wt.-%, (d) the intrinsic viscosity (IV) determined according to DIN ISO 1628/1 (in decalin at 135 C.) of the xylene cold soluble (XCS) fraction of the propylene copolymer is in the range of more than 1.5 to below 3.0 dl/g, and (e) the relative content of isolated to block ethylene sequences (I(E)) of the XCS fraction fulfilling the inequation (I)
I(E)<781.97C2+0.015(C2).sup.2(I) wherein C2 is the comonomer content [wt %] of the XCS fraction and wherein the I(E) content is defined by equation (II)
I(E)=fPEP/((fEEE+fPEE+fPEP))100(II) wherein I(E) is the relative content of isolated to block ethylene sequences [in %]; fPEP is the mol fraction of propylene/ethylene/propylene sequences (PEP) in the sample; fPEE is the mol fraction of propylene/ethylene/ethylene sequences (PEE) and of ethylene/ethylene/propylene sequences (EEP) in the sample; fEEE is the mol fraction of ethylene/ethylene/ethylene sequences (EEE) in the sample wherein all sequence concentrations are based on a statistical triad analysis of 13C-NMR data.

11. The polymerization process according to claim 10, wherein steps a), c), and e) of claim 10 are carried out in the presence of a) a Ziegler-Natta catalyst (ZN-C) comprising compounds (TC) of a transition metal of Group 4 to 6 of IUPAC, a Group 2 metal compound (MC) and an internal donor (ID), wherein said internal donor (ID) is a non-phthalic compound, b) a co-catalyst (Co), and c) optionally an external donor (ED).

12. The polymerization process according to claim 11, wherein the internal donor (ID) is selected from the group consisting of malonates, maleates, succinates, glutarates, cyclohexene-1,2-dicarboxylates, benzoates, derivatives and mixtures thereof.

13. A molded article comprising a heterophasic propylene copolymer (RAHECO), wherein the heterophasic propylene copolymer (RAHECO) comprises: (a) a xylene cold soluble content (XCS) determined according ISO 16152 (25 C.) in the range of 25.0 to 35.0 wt.-%, and (b) a comonomer content in the range of more than 4.5 to 10.0 wt.-%, wherein further (c) the comonomer content of xylene cold soluble (XCS) fraction of the propylene copolymer is in the range of 12.0 to 22.0 wt.-%, (d) the intrinsic viscosity (IV) determined according to DIN ISO 1628/1 (in decalin at 135 C.) of the xylene cold soluble (XCS) fraction of the propylene copolymer is in the range of more than 1.5 to below 3.0 dl/g, and (e) the relative content of isolated to block ethylene sequences (I(E)) of the XCS fraction fulfilling the inequation (I)
I(E)<781.97C2+0.015(C2).sup.2(I) wherein C2 is the comonomer content [wt %] of the XCS fraction and wherein the I(E) content is defined by equation (II)
I(E)=fPEP/((fEEE+fPEE+fPEP))100(II) wherein I(E) is the relative content of isolated to block ethylene sequences [in %]; fPEP is the mol fraction of propylene/ethylene/propylene sequences (PEP) in the sample; fPEE is the mol fraction of propylene/ethylene/ethylene sequences (PEE) and of ethylene/ethylene/propylene sequences (EEP) in the sample; fEEE is the mol fraction of ethylene/ethylene/ethylene sequences (EEE) in the sample wherein all sequence concentrations are based on a statistical triad analysis of 13C-NMR data.

14. The molded article according to claim 13, wherein the article is a bottle.

15. The polymerization process according to claim 11, wherein the non-phthalic compound comprises a non-phthalic acid ester.

16. The polymerization process according to claim 12, wherein the internal donor (ID) is a citraconate.

17. The molded article according to claim 13, wherein the molded article is an extrusion blow molded article.

18. The molded article according to claim 14, wherein the molded article is an extrusion blow molded article.

19. The polymerization process according to claim 15, wherein the internal donor (ID) is selected from the group consisting of malonates, maleates, succinates, glutarates, cyclohexene-1,2-dicarboxylates, benzoates, derivatives and mixtures thereof.

20. The polymerization process according to claim 19, wherein the internal donor (ID) is a citraconate.

Description

(1) Detailed description of preparation of catalysts is disclosed in WO 2012/007430, EP 2610271, EP 261027 and EP 2610272 which are incorporated here by reference.

(2) The Ziegler-Natta catalyst is preferably used in association with an alkyl aluminum cocatalyst and optionally external donors.

(3) As further component in the instant polymerization process an external donor is preferably present. Suitable external donors include certain silanes, ethers, esters, amines, ketones, heterocyclic compounds and blends of these. It is especially preferred to use a silane. It is most preferred to use silanes of the general formula
R.sup.a.sub.pR.sup.b.sub.qSi(OR.sup.c).sub.(4pq)

(4) wherein R.sup.a, R.sup.b and R.sup.c denote a hydrocarbon radical, in particular an alkyl or cycloalkyl group, and wherein p and q are numbers ranging from 0 to 3 with their sum p+q being equal to or less than 3. R.sup.a, R.sup.b and R.sup.c can be chosen independently from one another and can be the same or different. Specific examples of such silanes are (tert-butyl).sub.2Si(OCH.sub.3).sub.2, (cyclohexyl)(methyl)Si(OCH.sub.3).sup.2, (phenyl).sub.2Si(OCH.sub.3).sub.2 and (cyclopentyl).sub.2Si(OCH.sub.3).sub.2, or of general formula
Si(OCH.sub.2CH.sub.3).sub.3(NR.sup.3R.sup.4)

(5) wherein R.sup.3 and R.sup.4 can be the same or different a represent a hydrocarbon group having 1 to 12 carbon atoms.

(6) R.sup.3 and R.sup.4 are independently selected from the group consisting of linear aliphatic hydrocarbon group having 1 to 12 carbon atoms, branched aliphatic hydrocarbon group having 1 to 12 carbon atoms and cyclic aliphatic hydrocarbon group having 1 to 12 carbon atoms. It is in particular preferred that R.sup.3 and R.sup.4 are independently selected from the group consisting of methyl, ethyl, n-propyl, n-butyl, octyl, decanyl, iso-propyl, iso-butyl, iso-pentyl, tert.-butyl, tert.-amyl, neopentyl, cyclopentyl, cyclohexyl, methylcyclopentyl and cycloheptyl.

(7) More preferably both R.sup.1 and R.sup.2 are the same, yet more preferably both R.sup.3 and R.sup.4 are an ethyl group.

(8) Especially preferred external donors are the dicyclopentyl dimethoxy silane donor (D-donor) or the cyclohexylmethyl dimethoxy silane donor (C-Donor).

(9) In addition to the Ziegler-Natta catalyst and the optional external donor a co-catalyst can be used. The co-catalyst is preferably a compound of group 13 of the periodic table (IUPAC), e.g. organo aluminum, such as an aluminum compound, like aluminum alkyl, aluminum halide or aluminum alkyl halide compound. Accordingly, in one specific embodiment the co-catalyst is a trialkylaluminium, like triethylaluminium (TEAL), dialkyl aluminium chloride or alkyl aluminium dichloride or mixtures thereof. In one specific embodiment the co-catalyst is triethylaluminium (TEAL).

(10) Preferably the ratio between the co-catalyst (Co) and the external donor (ED) [Co/ED] and/or the ratio between the co-catalyst (Co) and the transition metal (TM) [Co/TM] should be carefully chosen.

(11) Accordingly, (a) the mol-ratio of co-catalyst (Co) to external donor (ED) [Co/ED] must be in the range of 5 to 45, preferably is in the range of 5 to 35, more preferably is in the range of 5 to 25; and optionally (b) the mol-ratio of co-catalyst (Co) to titanium compound (TC) [Co/TC] must be in the range of above 80 to 500, preferably is in the range of 100 to 350, still more preferably is in the range of 120 to 300.

(12) According to a further preferred embodiment, the heterophasic propylene copolymer (RAHECO) according to this invention is produced in the sequential polymeriszation process as defined above, preferably in the presence of

(13) (a) a Ziegler-Natta catalyst comprising compounds (TC) of a transition metal of Group 4 to 6 of IUPAC, a Group 2 metal compound (MC) and an internal donor (ID), wherein said internal donor (ID) is a non-phthalic compound, preferably is a non-phthalic acid ester and still more preferably is a diester of non-phthalic dicarboxylic acids;

(14) (b) optionally a co-catalyst (Co), and

(15) (c) optionally an external donor (ED).

(16) It is preferred that the internal donor (ID) is selected from malonates, maleates, succinates, glutarates, cyclohexene-1,2-dicarboxylates, benzoates, and derivatives and/or mixtures thereof, preferably the internal donor (ID) is a citraconate. Additionally or alternatively, the molar-ratio of co-catalyst (Co) to external donor (ED) [Co/ED] is 5 to 45.

(17) The additives as stated above are added to the heterophasic propylene copolymer (RAHECO) preferably by extruding. For mixing/extruding, a conventional compounding or blending apparatus, e.g. a Banbury mixer, a 2-roll rubber mill, Buss-co-kneader or a twin screw extruder may be used. The polymer materials recovered from the extruder are usually in the form of pellets. These pellets are then further processed, e.g. by a (blow) mold forming process as described above.

(18) In the following the present invention is further illustrated by means of examples.

EXAMPLES

1. Measuring Methods

(19) 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.

(20) Quantification of Microstructure by NMR Spectroscopy

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

(22) 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.

(23) For propylene homopolymers approximately 200 mg of material was dissolved in 1,2-tetrachloroethane-d.sub.2 (TCE-d.sub.2). 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 (8 k) transients were acquired per spectra.

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

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

(26) 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.

(27) 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).

(28) 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.

(29) 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)

(30) 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).

(31) 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.sub.21e=(I.sub.e6+I.sub.e8)/2

(32) 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:
P.sub.12=I.sub.CH3+P.sub.12e

(33) The total amount of propene was quantified as the sum of primary inserted propene and all other present regio-defects:
P.sub.total=P.sub.12+P.sub.21e

(34) 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)
Comonomer Determination by NMR Spectroscopy

(35) Quantitative nuclear-magnetic resonance (NMR) spectroscopy was further used to quantify the comonomer content and comonomer sequence distribution of the polymers. 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 (Singh, G., Kothari, A., Gupta, V., Polymer Testing 28 5 (2009), 475). 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 and quantitatively needed for accurate ethylene content quantification. Standard single-pulse excitation was employed without NOE, using an optimised tip angle, 1 s recycle delay and a bi-level WALTZ16 decoupling scheme (Zhou, Z., Kuemmerle, R., Qiu, X., Redwine, D., Cong, R., Taha, A., Baugh, D. Winniford, B., J. Mag. Reson. 187 (2007) 225; Busico, V., Carbonniere, P., Cipullo, R., Pellecchia, R., Severn, J., Talarico, G., Macromol. Rapid Commun. 2007, 28, 1128). A total of 6144 (6 k) transients were acquired per spectra.

(36) Quantitative .sup.13C{.sup.1H} NMR spectra were processed, integrated and relevant quantitative properties determined from the integrals using proprietary computer programs. All chemical shifts were indirectly referenced to the central methylene group of the ethylene block (EEE) at 30.00 ppm using the chemical shift of the solvent. This approach allowed comparable referencing even when this structural unit was not present. Characteristic signals corresponding to the incorporation of ethylene were observed Cheng, H. N., Macromolecules 17 (1984), 1950).

(37) 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.

(38) The comonomer fraction was quantified using the method of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157) through integration of multiple signals across the whole spectral region in the .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.

(39) For systems where only isolated ethylene in PPEPP sequences was observed the method of Wang et. al. was modified to reduce the influence of non-zero integrals of sites that are known to not be present. This approach reduced the overestimation of ethylene content for such systems and was achieved by reduction of the number of sites used to determine the absolute ethylene content to:
E=0.5(S+S+S+0.5(S+S))

(40) Through the use of this set of sites the corresponding integral equation becomes:
E=0.5(I.sub.H+I.sub.G+0.5(I.sub.C+I.sub.D))

(41) using the same notation used in the article of Wang et. al. (Wang, W-J., Zhu, S., Macromolecules 33 (2000), 1157). Equations used for absolute propylene content were not modified.

(42) The mole percent comonomer incorporation was calculated from the mole fraction:
E[mol %]=100*fE

(43) The weight percent comonomer incorporation was calculated from the mole fraction:
E[wt %]=100*(fE*28.06)/((fE*28.06)+((1fE)*42.08))

(44) The comonomer sequence distribution at the triad level was determined using the analysis method of Kakugo et al. (Kakugo, M., Naito, Y., Mizunuma, K., Miyatake, T. Macromolecules 15 (1982) 1150). This method was chosen for its robust nature and integration regions slightly adjusted to increase applicability to a wider range of comonomer contents.

(45) Calculation of comonomer content of the second propylene copolymer fraction (R-PP2):

(46) $\begin{array}{cc}\frac{C\left(\mathrm{PP}\right)-w\left(\mathrm{PP}1\right)C\left(\mathrm{PP}1\right)}{w\left(\mathrm{PP}2\right)}=C\left(\mathrm{PP}2\right)& \left(I\right)\end{array}$

(47) wherein

(48) w(PP1) is the weight fraction [in wt.-%] of the first random propylene copolymer fraction (R-PP1),

(49) w(PP2) is the weight fraction [in wt.-%] of second propylene copolymer fraction (R-PP2),

(50) C(PP1) is the comonomer content [in wt.-%] of the first random propylene copolymer fraction (R-PP1),

(51) C(PP) is the comonomer content [in wt.-%] of the random propylene copolymer (R-PP),

(52) C(PP2) is the calculated comonomer content [in wt.-%] of the second random propylene copolymer fraction (R-PP2).

(53) Calculation of the xylene cold soluble (XCS) content of the second propylene copolymer fraction (R-PP2):

(54) $\begin{array}{cc}\frac{\mathrm{XS}\left(\mathrm{PP}\right)-w\left(\mathrm{PP}1\right)\mathrm{XS}\left(\mathrm{PP}1\right)}{w\left(\mathrm{PP}2\right)}=\mathrm{XS}\left(\mathrm{PP}2\right)& \left(\mathrm{II}\right)\end{array}$

(55) wherein

(56) w(PP1) is the weight fraction [in wt.-%] of the first random propylene copolymer fraction (R-PP1),

(57) w(PP2) is the weight fraction [in wt.-%] of second random propylene copolymer fraction (R-PP2),

(58) XS(PP1) is the xylene cold soluble (XCS) content [in wt.-%] of the first random propylene copolymer fraction (R-PP1),

(59) XS(PP) is the xylene cold soluble (XCS) content [in wt.-%] of the random propylene copolymer (R-PP),

(60) XS(PP2) is the calculated xylene cold soluble (XCS) content [in wt.-%] of the second random propylene copolymer fraction (R-PP2).

(61) Calculation of melt flow rate MFR.sub.2 (230 C.) of the second propylene copolymer fraction (R-PP2):

(62) $\begin{array}{cc}\mathrm{MFR}\left(\mathrm{PP}2\right)={10}^{\left[\frac{\log \left(\mathrm{MFR}\left(\mathrm{PP}\right)\right)-w\left(\mathrm{PP}1\right)\log \left(\mathrm{MFR}\left(\mathrm{PP}1\right)\right)}{w\left(\mathrm{PP}2\right)}\right]}& \left(\mathrm{III}\right)\end{array}$

(63) wherein

(64) w(PP1) is the weight fraction [in wt.-%] of the first random propylene copolymer fraction (R-PP1),

(65) w(PP2) is the weight fraction [in wt.-%] of second random propylene copolymer fraction (R-PP2),

(66) MFR(PP1) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the first random propylene copolymer fraction (R-PP1),

(67) MFR(PP) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the random propylene copolymer (R-PP),

(68) MFR(PP2) is the calculated melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the second random propylene copolymer fraction (R-PP2).

(69) Calculation of comonomer content of the elastomeric propylene copolymer (E), respectively:

(70) $\begin{array}{cc}\frac{C\left(\mathrm{RAHECO}\right)-w\left(\mathrm{PP}\right)C\left(\mathrm{PP}\right)}{w\left(E\right)}=C\left(E\right)& \left(\mathrm{IV}\right)\end{array}$

(71) wherein

(72) w(PP) is the weight fraction [in wt.-%] of the random propylene copolymer (R-PP), i.e. polymer produced in the first and second reactor (R1+R2),

(73) w(E) is the weight fraction [in wt.-%] of the elastomeric propylene copolymer (E), i.e. polymer produced in the third reactor (R3)

(74) C(PP) is the comonomer content [in wt.-%] of the random propylene copolymer (R-PP), i.e. comonomer content [in wt.-%] of the polymer produced in the first and second reactor (R1+R2),

(75) C(RAHECO) is the comonomer content [in wt.-%] of the propylene copolymer, i.e. is the comonomer content [in wt.-%] of the polymer obtained after polymerization in the third reactor (R4),

(76) C(E) is the calculated comonomer content [in wt.-%] of elastomeric propylene copolymer (E), i.e. of the polymer produced in the third reactor (R3).

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

(78) Comonomer content, especially ethylene content is measured with Fourier transform infrared spectroscopy (FTIR) calibrated with .sup.13C-NMR. When measuring the ethylene content in polypropylene, a thin film of the sample (thickness about 250 m) was prepared by hot-pressing. The area of absorption peaks 720 and 733 cm.sup.1 for propylene-ethylene-copolymers was measured with Perkin Elmer FTIR 1600 spectrometer. Propylene-1-butene-copolymers were evaluated at 767 cm.sup.1. The method was calibrated by ethylene content data measured by .sup.13C-NMR. See also IR-Spektroskopie fr Anwender; WILEY-VCH, 1997 and Validierung in der Analytik, WILEY-VCH, 1997

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

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

(81) Hexane soluble (C6-solubles, wt.-%): Content of hexane soluble is measured according to European Pharmacopoeia 6.0, EP316

(82) 10 g of a sample taken from 0.3 mm thick bottles was put into a 300 ml Erlenmeyer flask and 100 ml of n-hexane was added. The mixture was boiled under stirring in a reflux condenser for 4 h. The hot solution was cooled down under stirring for 45 min and filtered under vacuum (G4 glasfilter) and the filtrate is put into a round shenk (dried in a vacuum oven at 90 C. and weighted with 0.0001 g exactly). Then the hexane was evaporated under a nitrogen stream on a rotary evaporator. The round shenk was dried in a vacuum oven at 90 C. over night and was put into a desiccator for at least 2 hours to cool down. The shenk was weighted again and the hexane soluble was calculated therefrom.

(83) Number Average Molecular Weight (M.sub.n), Weight Average Molecular Weight (M.sub.w) and Polydispersity (Mw/Mn)

(84) are determined by Gel Permeation Chromatography (GPC) according to the following method:

(85) The weight average molecular weight Mw and the polydispersity (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.

(86) 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 Mettler TA820 differential scanning calorimetry (DSC) on 5 to 10 mg samples. DSC is run according to ISO 3146/part 3/method C2 in a heat/cool/heat cycle with a scan rate of 10 C./min in the temperature range of +23 to +210 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

(87) Flexural Modulus: The flexural modulus was determined in 3-point-bending at 23 C. according to ISO 178 on 80104 mm.sup.3 test bars injection moulded in line with EN ISO 1873-2

(88) Description/Dimension of the Bottles

(89) 1 l bottles, having an outer diameter of 90 mm, wall thickness: 0.3 mm; overall-height of 204 mm, height of the cylindrical mantle of 185 mm

(90) Steam sterilization was performed in a Systec D series machine (Systec Inc., USA). The samples were heated up at a heating rate of 5 C./min starting from 23 C. After having been kept for 30 min at 121 C., they were removed immediately from the steam sterilizer and stored at room temperature till processed further.

(91) Transparency, Clarity, and Haze Measurement on Bottles

(92) Instrument: Haze-gard plus from BYK-Gardner

(93) Testing: according to ASTM D1003 (as for injection molded plates)

(94) Method: The measurement is done on the outer wall of the bottles. The top and bottom of the bottles are cut off. The resulting round wall is then split in two, horizontally. Then from this wall six equal samples of app. 6060 mm are cut from close to the middle. The specimens are placed into the instrument with their convex side facing the haze port. Then the transparency, haze and clarity are measured for each of the six samples and the haze value is reported as the average of these six parallels.

(95) Gloss Measurement on Bottles

(96) Instrument: Sceen TRI-MICROGLOSS 20-60-80 from BYK-Gardner 20

(97) Testing: ASTM D 2457 (as for injection molded plates)

(98) The bottles: It is measured on the wall of the bottles. The top and bottom of the bottles is cut off. This round wall is then split in two, horizontally. Then this wall is cut into six equal 25 samples of app. 9090 mm, just to fit into a special light trap made for testing on injection molded parts. Then the gloss at 20 is measured on these six samples, and the average value is reported as gloss at 20.

2. Examples

Catalyst for Inventive Examples

(99) The catalyst used in the polymerization process for the heterophasic polypropylene copolymer (RAHECO) of the inventive examples (IE1) was prepared as follows:

(100) Used chemicals:

(101) 20% solution in toluene of butyl ethyl magnesium (Mg(Bu)(Et), BEM), provided by Chemtura

(102) 2-ethylhexanol, provided by Amphochem

(103) 3-Butoxy-2-propanol(DOWANOL PnB), provided by Dow

(104) bis(2-ethylhexyl)citraconate, provided by SynphaBase

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

(106) Toluene, provided by Aspokem

(107) Viscoplex 1-254, provided by Evonik

(108) Heptane, provided by Chevron

(109) Preparation of the Mg Alkoxy Compound:

(110) Mg alkoxide solution was prepared by adding, with stirring (70 rpm), into 11 kg of a 20 wt % solution in toluene of butyl ethyl magnesium (Mg(Bu)(Et)), 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 addition was completed, mixing (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. Mixing was continued for 15 minutes under stirring (70 rpm).

(111) Preparation of Solid Catalyst Component

(112) 20.3 kg of TiCl.sub.4 and 1.1 kg of toluene were added into a 20 l stainless steel reactor. Under 350 rpm mixing and keeping the temperature at 0 C., 14.5 kg of the Mg alkoxy compound prepared in example 1 was added during 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. within 1 hour. After 30 minutes mixing was stopped catalyst droplets were solidified and the formed catalyst particles were allowed to settle. After settling (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.

(113) The thus obtained catalyst was used along with triethyl-aluminium (TEAL) as co-catalyst and di(cyclopentyl) dimethoxy silane (D-donor) as donor.

(114) The molar ratio of co-catalyst (Co) to external donor (ED) [Co/ED] and the molar ratio of co-catalyst (Co) to titanium compound (TC) [Co/TC] are indicated in table 1.

(115) Polymerization was performed in a Borstar pilot plant, comprising a prepolymerization reactor, a loop reactor and two or three gas phase reactors. The polymerization conditions are also indicated in table 1.

Catalyst for Comparative Examples

(116) The catalyst used in the polymerization process for comparative examples CE1 has been produced as follows: 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.sub.4 was 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. during 90 minutes and the slurry was allowed to stand for 60 minutes. Then, another 300 ml of TiCl.sub.4 was 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 EP491566, EP591224 and EP586390. As co-catalyst triethyl-aluminium (TEAL) and as donor dicyclo pentyl dimethoxy silane (D-donor) was used. The aluminium to donor ratio is also indicated in table 1.

Production of Inventive and Comparative Examples

(117) Polymerization was performed in a Borstar pilot plant, comprising a prepolymerization reactor, a loop reactor and two or three gas phase reactors. The polymerization conditions are indicated in Table 1. The properties of IE and CE are listed in Table 2 and Table 3.

(118) Before the polymerization, 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. As additives 0.04 wt. % synthetic hydrotalcite (DHT-4A supplied by Kisuma Chemicals, Netherlands) and 0.15 wt % Irganox B 215 (1:2-blend of Irganox 1010 (Pentaerythrityl-tetrakis(3-(3,5-di-tert.butyl-4-hydroxytoluyl)-propionate and tris (2,4-di-t-butylphenyl) t-butylphenyl) phosphate) phosphite) of BASF AG, Germany were added to the polymers in the same step. For the production of 1 liter round bottles like used for testing in the inventive work a Fischer Mller Blow Molding Machine was used. The main processing parameters for the production are as follows: Temperature profile: 180 to 200 C. applied in extruder, adapter and head Melt temperature measured: 190 to 200 C. Speed of extruder (revolution per minute; rpm): 13 to 16 rpm Die gap: the die gap was adjusted to get a bottle with a weight of 40 g with Borealis grade RB307MO (random propylene copolymer with a density of 902 kg/m.sup.3 and a MFR.sub.2 of 1.5 g/10 min) Cycle time: 12 to 16 seconds

(119) TABLE-US-00001 TABLE 1 Polymerization conditions IE1 CE1 TEAL/D [mol/mol] 7.7 15 Loop MFR.sub.2 [g/10 min] 5.7 3.4 C2 content [wt.-%] 2.1 2.0 XCS [wt.-%] 4.8 3.8 H.sub.2/C3 ratio [mol/kmol] 1.13 2.99 C2/C3 ratio [mol/kmol] 4.57 3.96 1 GPR MFR.sub.2 [g/10 min] 1.9 1.1 C2 content [wt.-%] 5.6 5.1 XCS [wt.-%] 15.6 15.8 H.sub.2/C3 ratio [mol/kmol] 2.8 5.2 C2/C3 ratio [mol/kmol] 40.6 51.8 2 GPR MFR.sub.2 [g/10 min] 1.4 1.1 C2 content [wt.-%] 8.1 9.0 XCS [wt.-%] 31.2 32.8 Tm [ C.] 147 150 H.sub.2/C3 ratio [mol/kmol] 103 369 C2/C3 ratio [mol/kmol] 104 152 Split Loop [wt.-%] 40.0 34.3 1 GPR [wt.-%] 47.1 45.5 2 GPR [wt.-%] 12.9 20.2

(120) TABLE-US-00002 TABLE 2 Properties IE1 CE1 MFR.sub.2 [g/10 min] 1.7 1.1 C2 [wt.-%] 8.1 9.0 XCS [wt.-%] 31.2 32.8 Tm [ C.] 147 150 C2 of XCS [wt.-%] 17.6 18.4 IV of XCS [dl/g] 2.6 2.5 Mw/Mn of XCS [] 6.5 6.4 C2 of XCI [wt.-%] 3.7 4.4 Mw/Mn of XCI [] 5.6 5.2 I(E) [] 47 51 Flex Modulus [MPa] 441 516 C6-Solubles [wt.-%] 3.1 4.2

(121) TABLE-US-00003 TABLE 3 Properties on EBM bottles IE1 CE1 Clarity b.s. [%] 79 67 Clarity a.s [%] 79 66 Haze b.s. [%] 34 25 Haze a.s. [%] 36 26 Gloss 20 b.s. [%] 9 7 Gloss 20 a.s. [%] 7 8