Polypropylene composition for foaming applications

Abstract

The present invention is directed to a polypropylene composition (C) comprising a heterophasic propylene copolymer and an inorganic filler, the use of said polypropylene composition (C) for the production of a foamed article and a foamed article obtained from said polypropylene composition (C).

Claims

1. A polypropylene composition (C), comprising: a) at least 20 wt. %, based on the overall weight of the polypropylene composition (C), of a heterophasic propylene copolymer (HECO1) comprising: i) a matrix (M) comprising a first propylene polymer (PP1), and ii) an elastomeric propylene copolymer (E), b) at least 30 wt. %, based on the overall weight of the polypropylene composition (C), of a second propylene polymer (PP2), c) a propylene homopolymer (H-PP3) having a melt flow rate MFR.sub.2 (230 C.) determined according to ISO 1133 below 50 g/10 min, d) an adhesion promoter (AP), and e) an inorganic filler (F), wherein said first propylene polymer (PP1) and said second propylene polymer (PP2) have melt flow rates MFR.sub.2 (230 C.) determined according to ISO 1133 above 50 g/10 min.

2. The polypropylene composition (C) according to claim 1, wherein the heterophasic propylene copolymer (HECO1) has a melt flow rate MFR.sub.2 (230 C.) determined according to ISO 1133 in the range of 10 to 30 g/10 min.

3. The polypropylene composition (C) according to claim 2, comprising: a) 20 to 40 wt. % of the heterophasic propylene copolymer (HECO1) comprising the first propylene copolymer (PP1) and the elastomeric propylene copolymer (E), b) 30 to 55 wt. % of the second propylene polymer (PP2), c) 5 to 25 wt. % of the propylene homopolymer (H-PP3), d) 0.5 to 5 wt. % of the adhesion promoter (AP), and e) 10 to 30 wt. % of the inorganic filler (F), based on the overall weight of the polypropylene composition (C).

4. The polypropylene composition (C) according to claim 1, wherein the inorganic filler (F) is glass fibers.

5. The polypropylene composition (C) according to claim 1, wherein the adhesion promoter (AP) is a polar modified polypropylene (PM-PP) being a propylene homo- or copolymer grafted with maleic anhydride having a melt flow rate MFR (190 C.) determined according to ISO 1133 of at least 50 g/10 min.

6. The polypropylene composition (C) according to claim 1, wherein the heterophasic propylene copolymer (HECO1) has: i) a comonomer content in the range of 5.0 to 35.0 mol %, and/or ii) a xylene soluble fraction (XCS) in the range of 15.0 to 40.0 wt. %, based on the overall weight of the heterophasic propylene copolymer (HECO1).

7. The polypropylene composition (C) according to claim 1, wherein the heterophasic propylene copolymer (HECO1) has an intrinsic viscosity of the xylene soluble fraction (XCS) measured according to ISO 1628/1 (at 135 C. in decalin) in the range of 1.0 to 4.5 dl/g.

8. The polypropylene composition (C) according to claim 1, wherein the first propylene polymer (PP1) and/or the second propylene polymer (PP2) are propylene homopolymers.

9. The polypropylene composition (C) according to claim 1, wherein the elastomeric propylene copolymer (E) is a copolymer of propylene and ethylene.

10. The polypropylene composition (C) according to claim 1, having a melt flow rate MFR.sub.2 (230 C.) determined according to ISO 1133 in the range of 8 to 30 g/10 min.

11. The polypropylene composition (C) according to claim 1, wherein said polypropylene composition (C) is a foamable polypropylene composition.

12. A foamed article, comprising the polypropylene composition (C) according to claim 1.

13. The foamed article according to claim 12, wherein said foamed article is an automotive article.

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 first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2):

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

(3) wherein w(PP1) is the weight fraction [in wt.-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), w(PP2) is the weight fraction [in wt.-%] of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2), C(PP1) is the comonomer content [in mol-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), C(PP) is the comonomer content [in mol-%] of the first propylene polymer and the first elastomeric propylene copolymer fraction, i.e. polymer produced in the first and second reactor (R1+R2), C(PP2) is the calculated comonomer content [in mol-%] of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2).

(4) Calculation of comonomer content of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2):

(5) $\begin{array}{cc}\frac{C\left(\mathrm{PP}\right)-w\left(\mathrm{PP}12\right)C\left(\mathrm{PP}12\right)}{w\left(\mathrm{PP}3\right)}=C\left(\mathrm{PP}3\right)& \left(\mathrm{II}\right)\end{array}$

(6) wherein w(PP12) is the weight fraction [in wt.-%] of the first propylene polymer fraction and the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), w(PP3) is the weight fraction [in wt.-%] of second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3), C(PP12) is the comonomer content [in mol-%] of the first propylene polymer fraction and the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), C(PP) is the comonomer content [in mol-%] of the first propylene polymer fraction, the first elastomeric propylene copolymer fraction and the second elastomeric propylene copolymer fraction, i.e. polymer produced in the first, second and third reactor (R1+R2+R3), C(PP3) is the calculated comonomer content [in mol-%] of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2).

(7) Calculation of the xylene cold soluble (XCS) content of the elastomeric propylene copolymer fraction, i.e. the polymer produced in the second and third reactor (R2+R3):

(8) $\begin{array}{cc}\frac{\mathrm{XS}\left(\mathrm{HECO}\right)-w\left(\mathrm{PP}1\right)\mathrm{XS}\left(\mathrm{PP}1\right)}{w\left(E\right)}=\mathrm{XS}\left(E\right)& \left(\mathrm{III}\right)\end{array}$

(9) wherein w(PP1) is the weight fraction [in wt.-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), w(E) is the weight fraction [in wt.-%] of the elastomeric propylene copolymer fraction, i.e. the polymer produced in the second and third reactor (R2+R3) XS(PP1) is the xylene cold soluble (XCS) content [in wt.-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), XS(HECO) is the xylene cold soluble (XCS) content [in wt.-%] of the first propylene polymer fraction, the first elastomeric propylene copolymer fraction and the second elastomeric propylene copolymer fraction, i.e. polymer produced in the first, second reactor and third reactor (R1+R2+R3), XS(E) is the calculated xylene cold soluble (XCS) content [in wt.-%] of the elastomeric propylene copolymer fraction, i.e. the polymer produced in the second and third reactor (R2+R3).

(10) Calculation of the xylene cold soluble (XCS) content of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2):

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

(12) wherein w(PP1) is the weight fraction [in wt.-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), w(PP2) is the weight fraction [in wt.-%] of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2) XS(PP1) is the xylene cold soluble (XCS) content [in wt.-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), XS(PP) is the xylene cold soluble (XCS) content [in wt.-%] of the first propylene polymer fraction and the first elastomeric propylene copolymer fractions, i.e. polymer produced in the first and second reactor (R1+R2), XS(PP2) is the calculated xylene cold soluble (XCS) content [in wt.-%] of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2).

(13) Calculation of the xylene cold soluble (XCS) content of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3):

(14) $\begin{array}{cc}\frac{\mathrm{XS}\left(\mathrm{PP}\right)-w\left(\mathrm{PP}12\right)\mathrm{XS}\left(\mathrm{PP}12\right)}{w\left(\mathrm{PP}3\right)}=\mathrm{XS}\left(\mathrm{PP}3\right)& \left(V\right)\end{array}$

(15) wherein w(PP12) is the weight fraction [in wt.-%] of the first propylene polymer fraction and the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the first reactor and second reactor (R1+R2), w(PP3) is the weight fraction [in wt.-%] of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3) XS(PP12) is the xylene cold soluble (XCS) content [in wt.-%] of the first propylene polymer fraction and the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), XS(PP) is the xylene cold soluble (XCS) content [in wt.-%] of the first propylene polymer fraction and the first and second elastomeric propylene copolymer fractions, i.e. polymer produced in the first, second reactor and third reactor (R1+R2+R3), XS(PP3) is the calculated xylene cold soluble (XCS) content [in wt.-%] of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3).

(16) Calculation of melt flow rate MFR.sub.2 (230 C.) of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2):

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

(18) wherein w(PP1) is the weight fraction [in wt.-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), w(PP2) is the weight fraction [in wt.-%] of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2), MFR(PP1) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), MFR(PP) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the first propylene polymer and the elastomeric first propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), MFR(PP2) is the calculated melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the first propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2).

(19) Calculation of melt flow rate MFR.sub.2 (230 C.) of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3):

(20) $\begin{array}{cc}\mathrm{MFR}\left(\mathrm{PP}3\right)={10}^{\left[\frac{\log \left(\mathrm{MFR}\left(\mathrm{PP}\right)\right)-w\left(\mathrm{PP}12\right)\log \left(\mathrm{MFR}\left(\mathrm{PP}12\right)\right)}{w\left(\mathrm{PP}3\right)}\right]}& \left(\mathrm{VII}\right)\end{array}$

(21) wherein w(PP12) is the weight fraction [in wt.-%] of the first propylene polymer fraction and the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), w(PP3) is the weight fraction [in wt.-%] of second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3), MFR(PP12) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the first propylene polymer fraction and the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), MFR(PP) is the melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the first propylene polymer, the first elastomeric propylene copolymer fraction and the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the first, second and third reactor (R1+R2+R3), MFR(PP3) is the calculated melt flow rate MFR.sub.2 (230 C.) [in g/10 min] of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3).

(22) Calculation of the intrinsic viscosity of the xylene soluble fraction of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2):

(23) $\begin{array}{cc}\frac{\mathrm{IV}\left(\mathrm{PP}\right)-\mathrm{XCS}\left(\mathrm{PP}1\right)\mathrm{IV}\left(\mathrm{PP}1\right)}{\mathrm{XCS}\left(\mathrm{PP}2\right)}=\mathrm{IV}\left(\mathrm{PP}2\right)& \left(\mathrm{VI}\right)\end{array}$

(24) wherein XCS(PP1) is the xylene soluble fraction [in wt.-%] of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), XCS(PP2) is the xylene soluble fraction [in wt.-%] of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2), IV(PP1) is the intrinsic viscosity [in dl/g] of the xylene soluble fraction of the first propylene polymer fraction, i.e. the polymer produced in the first reactor (R1), IV(PP) is the intrinsic viscosity [in dl/g] of the xylene soluble fraction of the first propylene polymer and the first elastomeric propylene copolymer fraction, i.e. polymer produced in the first and second reactor (R1+R2), IV(PP2) is the calculated intrinsic viscosity [in dl/g] of the xylene soluble fraction of the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the second reactor (R2).

(25) Calculation of the intrinsic viscosity of the xylene soluble fraction of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3):

(26) $\begin{array}{cc}\frac{\mathrm{IV}\left(\mathrm{PP}\right)-\mathrm{XCS}\left(\mathrm{PP}12\right)\mathrm{IV}\left(\mathrm{PP}12\right)}{\mathrm{XCS}\left(\mathrm{PP}3\right)}=\mathrm{IV}\left(\mathrm{PP}3\right)& \left(\mathrm{VII}\right)\end{array}$

(27) wherein XCS(PP12) is the xylene soluble fraction [in wt.-%] of the first propylene polymer fraction and the first elastomeric propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), XCS(PP3) is the xylene soluble fraction [in wt.-%] of second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3), IV(PP12) is the intrinsic viscosity [in dl/g] of the xylene soluble fraction of the first propylene polymer fraction and the elastomeric first propylene copolymer fraction, i.e. the polymer produced in the first and second reactor (R1+R2), IV(PP) is the intrinsic viscosity [in dl/g] of the xylene soluble fraction of the first propylene polymer fraction, the first elastomeric propylene copolymer fraction and the second elastomeric propylene copolymer fraction, i.e. polymer produced in the first, second and third reactor (R1+R2+R3), IV(PP3) is the calculated intrinsic viscosity [in dl/g] of the xylene soluble fraction of the second elastomeric propylene copolymer fraction, i.e. the polymer produced in the third reactor (R3).

(28) Calculation of comonomer content of the elastomeric propylene copolymer fraction, i.e. the polymer produced in the second and third reactor (R2+R3):

(29) 0$\begin{array}{cc}\frac{C\left(\mathrm{HECO}\right)-w\left(\mathrm{PP}\right)C\left(\mathrm{PP}\right)}{w\left(E\right)}=C\left(E\right)& \left(\mathrm{VIII}\right)\end{array}$

(30) wherein w(PP) is the weight fraction [in wt.-%] of the first propylene polymer, i.e. polymer produced in the first reactor (R1), w(E) is the weight fraction [in wt.-%] of the first elastomeric propylene copolymer fraction and the second elastomeric propylene copolymer fraction, i.e. of the polymer produced in the second and third reactor (R2+R3), C(PP) is the comonomer content [in mol-%] of the first propylene polymer, i.e. polymer produced in the first reactor (R1), C(HECO) is the comonomer content [in mol-%] of the propylene copolymer, i.e. is the comonomer content [in mol-%] of the polymer obtained after polymerization in the third reactor (R3), C(E) is the calculated comonomer content [in mol-%] of the first elastomeric propylene copolymer fraction and the second elastomeric propylene copolymer fraction, i.e. of the polymer produced in the second and third reactor (R2+R3).

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

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

(33) Quantification of Microstructure by NMR Spectroscopy

(34) Quantitative nuclear-magnetic resonance (NMR) spectroscopy was 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 (6k) transients were acquired per spectra. 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).

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

(36) 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.

(37) 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., Macromoleucles 30 (1997) 6251).

(38) 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.

(39) 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)

(40) 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.

(41) 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).

(42) 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

(43) 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

(44) 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

(45) 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)

(46) For copolymers characteristic signals corresponding to the incorporation of ethylene were observed (Cheng, H. N., Macromolecules 17 (1984), 1950).

(47) With regio defects also observed (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) correction for the influence of such defects on the comonomer content was required.

(48) 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.

(49) 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))

(50) 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))

(51) 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.

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

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

(54) 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.

(55) Number Average Molecular Weight (M.sub.n), Weight Average Molecular Weight (M.sub.w) and Molecular Weight Distribution (MWD)

(56) Molecular weight averages (Mw, Mn), and the molecular weight distribution (MWD), i.e. the Mw/Mn (wherein Mn is the number average molecular weight and Mw is the weight average molecular weight), were determined by Gel Permeation Chromatography (GPC) according to ISO 16014-4:2003 and ASTM D 6474-99. A PolymerChar GPC instrument, equipped with infrared (IR) detector was used with 3 Olexis and 1 Olexis Guard columns from Polymer Laboratories and 1,2,4-trichlorobenzene (TCB, stabilized with 250 mg/L 2,6-Di tert butyl-4-methyl-phenol) as solvent at 160 C. and at a constant flow rate of 1 mL/min 200 of sample solution were injected per analysis. The column set was calibrated using universal calibration (according to ISO 16014-2:2003) with at least 15 narrow MWD polystyrene (PS) standards in the range of 0.5 kg/mol to 11 500 kg/mol. Mark Houwink constants for PS, PE and PP used are as described per ASTM D 6474-99. All samples were prepared by dissolving 5.0-9.0 mg of polymer in 8 mL (at 160 C.) of stabilized TCB (same as mobile phase) for 2.5 hours for PP or 3 hours for PE at max. 160 C. under continuous gentle shaking in the autosampler of the GPC instrument.

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

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

(59) The xylene solubles (XCS, wt.-%): Content of xylene cold solubles (XCS) 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.

(60) Ash content is measured according to ISO 3451-1 (1997) standard.

(61) F.sub.30 Melt Strength and v.sub.30 Melt Extensibility

(62) The test described herein follows ISO 16790:2005.

(63) The strain hardening behaviour is determined by the method as described in the article Rheotens-Mastercurves and Drawability of Polymer Melts, M. H. Wagner, Polymer Engineering and Science, Vol. 36, pages 925 to 935. The content of the document is included by reference. The strain hardening behaviour of polymers is analysed by Rheotens apparatus (product of Gttfert, Siemensstr.2, 74711 Buchen, Germany) in which a melt strand is elongated by drawing down with a defined acceleration.

(64) The Rheotens experiment simulates industrial spinning and extrusion processes. In principle a melt is pressed or extruded through a round die and the resulting strand is hauled off. The stress on the extrudate is recorded, as a function of melt properties and measuring parameters (especially the ratio between output and haul-off speed, practically a measure for the extension rate). For the results presented below, the materials were extruded with a lab extruder HAAKE Polylab system and a gear pump with cylindrical die (L/D=6.0/2.0 mm). The gear pump was pre-adjusted to a strand extrusion rate of 5 mm/s, and the melt temperature was set to 200 C. The spinline length between die and Rheotens wheels was 80 mm. At the beginning of the experiment, the take-up speed of the Rheotens wheels was adjusted to the velocity of the extruded polymer strand (tensile force zero): Then the experiment was started by slowly increasing the take-up speed of the Rheotens wheels until the polymer filament breaks. The acceleration of the wheels was small enough so that the tensile force was measured under quasi-steady conditions. The acceleration of the melt strand drawn down is 120 mm/sec.sup.2. The Rheotens was operated in combination with the PC program EXTENS. This is a real-time data-acquisition program, which displays and stores the measured data of tensile force and drawdown speed. The end points of the Rheotens curve (force versus pulley rotary speed) is taken as the F.sub.30 melt strength and drawability values.

(65) Strain Hardening Factor (SHF)

(66) The strain hardening factor is defined as

(67) wherein

(68) $\mathrm{SHF}=\frac{{}_E^{+}\left(t,\mathrm{.Math.}\right)}{{}_{\mathrm{LVE}}^{+}\left(t\right)}=\frac{{}_E^{+}\left(t,\mathrm{.Math.}\right)}{3{}^{+}\left(t\right)}$

(69) .sub.E.sup.+(t,) is the uniaxial extensional viscosity; and .sub.LVE.sup.+(t) is three times the time dependent shear viscosity .sup.+(t) in the linear range of deformation.

(70) The determination of the linear viscoelastic envelop in extension .sub.LVE.sup.+(t), using IRIS Rheo Hub 2008, required the calculation of the discrete relaxation time spectrum from the storage and loss modulus data (G, G ()). The linear viscoelastic data (G, G ()) is obtained by frequency sweep measurements undertaken at 180 C. for polypropylene or at 140 for polyethylene, on a Anton Paar MCR 300 coupled with 25 mm parallel plates. The underlying calculation principles used for the determination of the discrete relaxation spectrum are described in Baumgrtel M, Winter H H, Determination of the discrete relaxation and retardation time spectra from dynamic mechanical data, Rheol. Acta 28:511519 (1989) which is incorporated by reference in its entirety.

(71) IRIS RheoHub 2008 expresses the relaxation time spectrum as a sum of N Maxwell modes

(72) $\stackrel{o}{G}\left(t\right)=G_e.Math.\underset{1}{\overset{N}{.Math.}}{g}_i.Math.e^{-\frac{t}{{}_i}}$

(73) wherein g.sub.i and .sub.i are material parameters and G.sub.e is the equilibrium modulus.

(74) The choice for the maximum number of modes, N used for determination of the discrete relaxation spectrum, is done by using the option optimum from IRIS RheoHub 2008. The equilibrium modulus G.sub.e was set at zero. The non-linear fitting used to obtain .sub.LVE.sup.+(t) is performed on IRIS Rheo Hub 2008, using the Doi-Edwards model.

(75) The uniaxial extensional viscosity, .sub.E.sup.|(t,) is obtained from uniaxial extensional flow measurements, conducted on an Anton Paar MCR 501 coupled with the Sentmanat extensional fixture (SER-1). The temperature for the uniaxial extensional flow measurements was set at 180 C., applying extension (strain) rates /t ranging from 0.3 s.sup.1 to 10 s.sup.1 and covering a range of Hencky strain
=ln[(ll.sub.0)/l.sub.0],

(76) with l.sub.0 being the original and l the actual sample fixation length, from 0.3 to 3.0. Particularly care was taken for the preparation of the samples for extensional flow. The samples were prepared by compression moulding at 230 C. followed by slow cooling to room temperature (forced water or air cooling were not used). This procedure allowed obtaining well shaped samples free of residual stresses. The sample was left for some minutes at the testing temperature to ensure thermal stability (set temperature0.1 C.), before carrying out the uniaxial extensional flow measurements.

(77) Maximum force, energy to maximum force, puncture energy were determined according to ISO 6603-2 on 210148X (A5) specimen cut from the center of injection moulded plaques with dimensions of 400200 mm. The test was performed at room temperature on a support of 100 mm diameter where the test specimen was hit with a lubricated striker (diameter of 20 mm) at impact speed of 4.4 m/s. The 400200 mm plaques were produced on an Engel Duo 450 injection moulding machine with a film gate on the small side. Foamed plates were generated via the physical Mucell foaming technology using supercritical nitrogen gas as a blowing agent. The injection-foaming was performed with 1 mm opening stroke i.e. foamed plates with 3 mm thickness were produced. For the sake of comparison 2 mm thick compact parts were produced, as well . . . .

2. Examples

(78) Polymerization of the heterophasic propylene copolymer (HECO1) and the second propylene polymer (PP2) was performed in continuous mode in a Borstar PP pilot plant with one loop and two gas phase reactors.

(79) The catalyst used in the polymerization process for the heterophasic propylene copolymer (HECO1) used in the inventive examples is the commercial catalyst ZN104 of Basell used along with dicyclopentyl dimethoxy silane (D-Donor) as donor and Triethylaluminium (TEAL) as co-catalyst.

(80) The catalyst used in the polymerization process for the second propylene polymer (PP2) used in the inventive examples is the commercial catalyst ZN M1 of Basell used along with cyclohexylmethyl dimethoxy silane (C-Donor) as donor.

(81) TABLE-US-00001 TABLE 1 Preparation of HECO1 and PP2 HECO1 PP2 Prepolymerization TEAL/Ti [mol/mol] 220 260 TEAL/donor [mol/mol] 30 10 Temperature [ C.] 20 30 res. time [h] 0.1 0.08 Loop Temperature [ C.] 70 75 Pressure [kPa] 5520 5300 Split [%] 64 H2/C3 ratio [mol/kmol] 15 12 C2/C3 ratio [mol/kmol] 0 0 MFR.sub.2 [g/10 min] 85 75 XCS [wt.-%] 2.0 2.6 C2 content [mol-%] 0.0 0.0 GPR 1 Temperature [ C.] 80 Pressure [kPa] 1600 Split [%] 13 H2/C2 ratio [mol/kmol] 120 C2/C3 ratio [mol/kmol] 510 MFR.sub.2 [g/10 min] 32 XCS [wt.-%] 25 C2 content [mol-%] 9.0 GPR 2 Temperature [ C.] 80 Pressure [kPa] 1450 Split [%] 23 C2/C3 ratio [mol/kmol] 1400 H2/C2 ratio [mol/kmol] 280 MFR.sub.2 [g/10 min] 18.0 XCS [wt.-%] 29.0 IV (XCS) [dl/g] 2.7 C2 (XCS) [mol-%] 48.0 C2 content [mol-%] 11.1 C2 ethylene H2/C3 ratio hydrogen/propylene ratio C2/C3 ratio ethylene/propylene ratio H2/C2 ratio hydrogen/ethylene ratio GPR 1/2/3 1st/2nd/3rd gas phase reactor Loop Loop reactor

(82) HECO1 and PP2 were mixed in a twin-screw extruder with 0.2 wt.-% of Irganox B225 (1:1-blend of Irganox 1010 (Pentaerythrityl-tetrakis(3-(3,5-di-tert.butyl-4-hydroxytoluyl)-propionate and tris (2,4-di-t-butylphenyl) phosphate) phosphite) of BASF AG, Germany) and 0.1 wt.-% calcium stearate, respectively.

(83) Preparation of the Composition (C)

(84) HECO1, PP2 and optionally one or more H-PP components were melt blended on a co-rotating twin screw extruder with the adhesion promoter (AP), plastomer (PL), glass fibers and carbon black. The polymer melt mixture was discharged and pelletized.

(85) TABLE-US-00002 TABLE 2 Properties of comparative and inventive examples CE1 CE2 IE1 IE2 IE3 HECO1 [wt.-%] 28.0 28.0 28.0 28.0 PP2 [wt.-%] 14.6 49.6 34.6 39.6 GF [wt.-%] 20.0 20.0 20.0 20.0 20.0 AP [wt.-%] 1.5 1.5 1.5 1.5 1.5 CB [wt.-%] 0.5 0.5 0.5 0.5 0.5 AO [wt.-%] 0.4 0.4 0.4 0.4 0.4 H-PP3a [wt.-%] 15.0 67.6 H-PP3b [wt.-%] 15.0 H-PP3c [wt.-%] 20.0 10.0 PL [wt.-%] 10.0 Ash content [wt.-%] 20.0 20.0 19.7 19.8 20.0 MFR [g/10 min] 9.1 27.3 12.0 12.6 11.8 Maximum Force [N] 527 533 574 551 632 Energy to [J] 2.2 1.5 2.5 2.0 2.7 Maximum Force Puncture Energy [J] 8.8 7.6 8.9 9.3 9.8 Cell structure [] coarse coarse reg- reg- reg- ular ular ular GF is the commercial product ECS 03 T-480H of Nippon Electric Glass Co., Ltd. having a filament diameter of 10.5 m and a strand length of 3 mm. AP is the adhesion promoter SCONA TPPP 8112 GA by Scona being a polypropylene functionalized with maleic anhydride having a maleic anhydride content of 1.4 wt.-% and a MFR (190 C.) above 80 g/10 min. CB is a masterbatch of 70 wt % of low density polyethylene (LDPE) and 30 wt % carbon black, with MFR (190/21.6 kg) of 2 g/10 min. AO is an antioxidant blend comprising ADK-STAB A-611 by ADK, Anox BB 011 by Chemtura, Evernox B110 by Everspring, Hostanox M 101 by Clariant, Irganox B 225 by BASF, Kinox-B25 by HPL Additives and Songnox 11B by Songwon. H-PP3a is the commercial propylene homopolymer HK060AE of Borealis, a visbroken grade based on Ziegler-Natta catalyst, having a melt flow rate MFR.sub.2 (230 C.) of 125 g/10 min and XCS content of 2.8 wt % H-PP3b is the commercial propylene homopolymer HG265FB of Borealis, a reactor grade based on Ziegler-Natta catalyst, having a melt flow rate MFR.sub.2 (230 C.) of 26 g/10 min and XCS content of 2.6 wt % H-PP3c is the commercial propylene homopolymer WE100HMS of Borealis, a long-chain branched high melt strength polypropylene (HMS-PP) produced by reactive modification in accordance to WO 2014/016206 A1. It has a melt flow rate MFR.sub.2 (230 C.) of 10 g/10 min and an F30 melt strength of 8.0 cN in combination with a melt extensibility v30 of >200 mm/s as determined in a Rheotens test as described in WO 2014/016206 A1. PL is the commercial ethylene-octene copolymer Queo8230 of Borealis having a density of 0.880 g/cm.sup.3, a melt flow rate MFR.sub.2 (190 C.) of 30.0 g/10 min and an 1-octene content of 7.0 mol-%.