Polypropylene-Polyethylene Composition with Improved Toughness

Abstract

It is provided a polymer composition including at least the following components A) 70 to 97 wt.-% based on the overall weight of the polymer composition of a polymer blend, including a1) 50 to 95 wt.-% of polypropylene; a2) 5 to 50 wt.-% of polyethylene; B) 3 to 30 wt.-% based on the overall weight of the polymer composition of a copolymer of propylene and 1-hexene, including b1) 30 to 70 wt.-% of a first random copolymer of propylene and 1-hexene; and b2) 30 to 70 wt.-% of a second random copolymer of propylene and 1-hexene having a higher 1-hexene content than the first random propylene copolymer b1); with the provisos that the weight proportions of components a1) and a2) add up to 100 wt.-%; the weight proportions of components b1) and b2) add up to 100 wt.-%; component A) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 1.0 to 50.0 g/10 min; component B) has a 1-hexene content in the range of 2.0 to 8.0 wt.-% based on the overall weight of component B); and the polymer composition is free from plastomers being an elastomeric copolymer of ethylene and 1-octene having a density in the range from 0.860 to 0.930 g/cm.sup.3.

Claims

1. A polymer composition comprising at least the following components A) 70 to 97 wt.-% based on the overall weight of the polymer composition of a polymer blend, comprising a1) 50 to 95 wt.-% of polypropylene; a2) 5 to 50 wt.-% of polyethylene; B) 3 to 30 wt.-% based on the overall weight of the polymer composition of a copolymer of propylene and 1-hexene, comprising b1) 30 to 70 wt.-% of a first random copolymer of propylene and 1-hexene; and b2) 30 to 70 wt.-% of a second random copolymer of propylene and 1-hexene having a higher 1-hexene content than the first random propylene copolymer b1); with the provisos that the weight proportions of components a1) and a2) add up to 100 wt.-%; the weight proportions of components b1) and b2) add up to 100 wt.-%; component A) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 1.0 to 50.0 g/10 min; component B) has a 1-hexene content in the range of 2.0 to 8.0 wt.-% based on the overall weight of component B); and the polymer composition is free from plastomers being an elastomeric copolymer of ethylene and 1-octene having a density in the range from 0.860 to 0.930 g/cm.sup.3.

2. The polymer composition according to claim 1, which, the content of component A) in the polymer composition is in the range from 75 to 95 wt.-%, preferably in the range from 78 to 92 wt.-% and more preferably in the range from 80 to 91 wt.-% based on the overall weight of the polymer composition; and/or the content of component B) in the polymer composition is in the range from 5 to 25 wt.-%, preferably in the range from 8 to 22 wt.-% and more preferably in the range from 9 to 20 wt.-% based on the overall weight of the polymer composition; and/or the content of polypropylene a1) in component A) is in the range from 53 to 92 wt.-%, preferably in the range from 55 to 90 wt.-% and more preferably in the range from 58 to 87 wt.-%; and/or the content of polyethylene a2) in component A) is in the range from 8 to 47 wt.-%, preferably in the range from 10 to 45 wt.-% and more preferably in the range from 13 to 42 wt.-%.

3. The polymer composition according to claim 1, wherein, component A) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 1.5 to 35.0 g/10 min, preferably in the range from 2.0 to 25.0 g/10 min and more preferably in the range from 5.0 to 10.0 g/10 min; and/or component B) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 0.4 to 12.0 g/10 min, preferably in the range from 0.6 to 9.0 g/10 min, more preferably in the range from 0.8 to 6.0 g/10 min and most preferably in the range from 1.0 to 4.0 g/10 min; and/or component B) has a xylene soluble content (XCS) based on the overall weight of component B) of ≥8, preferably in the range from 8 to 30 wt.-%, more preferably in the range from 10.0 to 28.0 wt.-% and most preferably in the range from 15 to 28 wt.-%; and/or the 1-hexene content in component B) is in the range from 3.0 to 7.5 wt.-%, preferably in the range from 3.5 to 7.2 wt.-% and more preferably in the range from 4.0 to 6.0 wt.-%; and/or component B) has a 1-hexene content of the xylene soluble fraction C6 (XCS) based on the overall weight of component B) in the range from 2.0 to 15.0 wt.-%, preferably from 2.5 to 12.0 wt.-%, more preferably in the range from 3.0 to 10.0 wt.-% and most preferably in the range from 5.0 to 8.0 wt.-%; and/or the melting point of component B) is >120° C., preferably in the range from 125 to 145° C. and more preferably in the range from 130 to 140° C.; and/or the melt enthalpy of component a2)/melt enthalpy of a1) in the polymer composition is in the range from 0.2 to 2.0 and preferably in the range from 0.25 to 1.75.

4. The polymer composition according to claim 1, wherein, the polymer composition has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 1.0 to 50.0 g/10 min, preferably from 1.5 to 35.0 g/10 min, more preferably from 2.0 to 25.0 g/10 min and most preferably from 3.5 to 8.0 g/10 min; and/or a Tensile Modulus measured according to ISO527-2 of above 900 MPa and preferably in the range from 900 to 1500 MPa; and/or a Flexible Modulus measured according to ISO178 of above 900 MPa and preferably in the range from 1000 to 1600 MPa; and/or a Charpy Notched Impact Strength measured according to ISO 179-1eA at 23° C. of >3 kJ/m.sup.2, preferably in the range from 3.3 to 30 kJ/m.sup.2, and more preferably from 3.3 to 10 kJ/m.sup.2.

5. The polymer composition according to claim 1, where, component b1) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 0.3 to 12.0 g/10 min, preferably in the range from 0.5 to 9.0 g/10 min and more preferably in the range from 0.7 to 6.0 g/10 min; and/or component b2) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 0.5 to 14.0 g/10 min, preferably in the range from 0.7 to 11.0 g/10 min and more preferably in the range from 0.9 to 8.0 g/10 min; and/or the C6-content in component b1) based on the overall weight of component b1) is in the range from 0.1 to 4.0 wt.-%, preferably in the range from 0.5 to 3.5 wt.-% and more preferably in the range from 0.8 to 3.0 wt.-%; and/or the C6-content in component b2) based on the overall weight of component b2) is in the range from 4.0 to 15.0 wt.-%, preferably in the range from 5.0 to 13.0 wt.-% and more preferably in the range from 6.0 to 12.0 wt.-%; and/or the content of component b1) in component B) is from 35 to 65 wt.-% and preferably from 40 to 60 wt.-%; and/or the content of component b2) in component B) is from 35 to 65 wt.-% and preferably from 40 to 60 wt.-%.

6. The polymer composition according to claim 1, wherein, component A) is a recycled material, which is preferably recovered from waste plastic material derived from post-consumer and/or post-industrial waste; and/or the polymer composition is free from plastomers; and/or the polymer composition comprises at least one additive, preferably selected from the group consisting of slip agents, UV-stabiliser, pigments, antioxidants, additive carriers, nucleating agents and mixtures thereof, whereby these additives preferably are present in 0 to 5 wt.-% and more preferably in 0.1 to 4 wt.-% based on the overall weight of the polymer composition.

7. The polymer composition according to claim 1, wherein, said polymer composition has a higher Charpy Notched Impact Strength measured according to ISO 179-1eA at 23° C., preferably at least 5% higher more preferably 5 to 15% higher and even more preferably at least 10% higher than the same polymer composition without component B); and has at the same time a Tensile Modulus measured according to IS0527-2 of above 900 MPa and preferably in the range from 900 to 1500 MPa.

8. The polymer composition according to claim 1, wherein, component B) is an in-reactor blend obtained by a sequential polymerization process in at least two reactors connected in series, said sequential polymerization process preferably comprises the steps of (i) polymerizing in a first reactor being a slurry reactor, preferably a loop reactor, propylene and 1-hexene, obtaining a first random propylene copolymer b1), (ii) transferring said first random propylene copolymer b1) and unreacted comonomers of the first reactor in a second reactor being a gas phase reactor, (iii) feeding to said second reactor propylene and 1-hexene, (iv) polymerizing in said second reactor and in the presence of said first random propylene copolymer b1) propylene and 1-hexene obtaining a second random propylene copolymer b2), said first random propylene copolymer b1) and said second random propylene copolymer b2) form component B), wherein further in the first reactor and second reactor the polymerization takes place in the presence of a solid catalyst system, said solid catalyst system (SCS) comprises a single-site catalyst.

9. The polymer composition according to claim 1, wherein, said polymer composition consists of the following components: C) 78 to 92 wt.-% based on the overall weight of the polymer composition of a polymer blend, comprising a1) 55 to 90 wt.-% of polypropylene; a2) 10 to 45 wt.-% of polyethylene; D) 8 to 22 wt.-% based on the overall weight of the polymer composition of a copolymer of propylene and 1-hexene, comprising b1) 30 to 70 wt.-% of a first random copolymer of propylene and 1-hexene; and b2) 30 to 70 wt.-% of a second random copolymer of propylene and 1-hexene having a higher 1-hexene content than the first random propylene copolymer b1). with the provisos that component A) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 2.0 to 25.0 g/10 min; component B) has a MFR.sub.2 (230° C., 2.16 kg) determined according to ISO 1133 in the range from 0.8 to 5.0 g/10 min component B) has a xylene soluble content (XCS) based on the overall weight of component B) in the range from 10 to 28 wt.-%; and the 1-hexene content in component B) is in the range from 3.5 to 7.2 wt.-%.

10-12. (canceled)

13. A process for compatibilizing the components of a polymer blend A) as described in claim 1 comprising the steps of (IV). providing the polymer blend A) as described in claim 1; (V). adding component B) as described in claim 1; (VI). mixing both components to obtain a compatibilized polymer composition.

14. The process according to claim 13, wherein, the polymer composition obtained after step (III) has a higher Charpy Notched Impact Strength measured according to ISO 179-1eA at 23° C., preferably at least 5% higher, more preferably from 5 to 10% higher and even more preferably at least 10% higher than the polymer blend A) provided in step (I) without component B); and has at the same time a Tensile Modulus measured according to ISO 527-2 of above 900 MPa and preferably in the range from 900 to 1500 MPa.

15. An article comprising a polymer composition according to claim 1.

16. The article according to claim 15 in form of a film, a pipe, an extrusion blow molded or injection molded article comprising more than 80 wt.-% of the polymer composition.

Description

EXPERIMENTAL PART

[0179] A. Measuring Methods

[0180] The following definitions of terms and determination methods apply for the above general description of the solution as well as to the below examples unless otherwise defined.

[0181] Melt Flow Rate (MFR)

[0182] MFR was measured according to ISO 1133 at a load of 2.16 kg, at 230° C. for the PP homo- and copolymers and blends and for the composition and at a load of 2.16 kg, at 190° C. for the PE hompolymers.

[0183] Melting Temperature T.sub.m, Melting Enthalpy H.sub.m and Crystallization Temperature T.sub.c

[0184] The parameters are determined with a TA Instrument Q2000 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 (T.sub.c) is determined from the cooling step, while melting temperature (T.sub.m) and melting enthalpy (H.sub.m) are determined from the second heating step. Melting and crystallization temperatures were taken as the peaks of endotherms and exotherms,

[0185] Tensile Modulus, Tensile Strength and Elongation at Break

[0186] Tensile modulus, tensile strength (tensile stress at yield) and elongation at break were determined according to ISO 527-2 (cross head speed=50 mm/min; 23° C.) using injection molded specimens as described in EN ISO 1873-2 (dog bone shape, 4 mm thickness).

[0187] Flexural Modulus

[0188] The flexural modulus is determined according to ISO 178. The test specimens have a dimension of 80×10×4.0 mm.sup.3 (length×width×thickness) and are prepared by injection molding according to EN ISO 1873-2. The length of the span between the supports: 64 mm and the test speed 2 m/min,

[0189] Charpy Notched Impact Strength

[0190] Charpy Notched impact strength was determined according to ISO 179 1eA at 23° C. using 80×10×4 mm.sup.3 test bars injection moulded in line with EN ISO 1873-2.

[0191] Xylene Cold Solubles (XCS)

[0192] The xylene soluble (XS) fraction as defined and described in the solution is determined in line with ISO 16152 as follows: 2.0 g of the polymer were dissolved in 250 ml p-xylene at 135° C. under agitation. After 30 minutes, the solution was allowed to cool for 15 minutes at ambient temperature and then allowed to settle for 30 minutes at 25+/−0.5° C. The solution was filtered with filter paper into two 100 ml flasks. The solution from the first 100 ml vessel was evaporated in nitrogen flow and the residue dried under vacuum at 90° C. until constant weight is reached. The xylene soluble fraction (percent) can then be determined as follows:

[0193] XS %=(100*m*V.sub.0)/(m.sub.0*v); m.sub.0=initial polymer amount (g); m=weight of residue (g); V.sub.0=initial volume (ml); v=volume of analysed sample (ml).

[0194] Comonomer Content of 1-Hexene for a Propylene 1-Hexene Copolymer

[0195] Quantitative .sup.13C{.sup.1H} NMR spectra recorded in the molten-state using a Bruker Avance 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 50 (2009) 2373). Standard single-pulse excitation was employed utilising the NOE at short recycle delays of 3 s (Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, H. W., Wilhelm, M., Macromol. Chem. Phys. 2006; 207:382, Pollard, M., Klimke, K., Graf, R., Spiess, H. W., Wilhelm, M., Sperber, O., Piel, C., Kaminsky, W., Macromolecules 2004; 37:813) 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 16384 (16 k) transients were acquired per spectra.

[0196] 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.

[0197] Characteristic signals corresponding to the incorporation of 1-hexene were observed and the comonomer content quantified in the following way.

[0198] The amount of 1-hexene incorporated in PHP isolated sequences was quantified using the integral of the αB4 sites at 44.2 ppm accounting for the number of reporting sites per comonomer:

H=IαB4/2

[0199] The amount of 1-hexene incorporated in PHHP double consecutive sequences was quantified using the integral of the ααB4 site at 41.7 ppm accounting for the number of reporting sites per comonomer:

HH=2*IααB4

[0200] When double consecutive incorporation was observed the amount of 1-hexene incorporated in PHP isolated sequences needed to be compensated due to the overlap of the signals αB4 and αB4B4 at 44.4 ppm:

H=(IαB4−2*IααB4)/2

[0201] The total 1-hexene content was calculated based on the sum of isolated and consecutively incorporated 1-hexene:

Htotal=H+HH

[0202] When no sites indicative of consecutive incorporation observed the total 1-hexen comonomer content was calculated solely on this quantity:

Htotal=H

[0203] Characteristic signals indicative of regio 2,1-erythro defects were observed (Resconi, L., Cavallo, L., Fait, A., Piemontesi, F., Chem. Rev. 2000, 100, 1253).

[0204] The presence of 2,1-erythro regio defects was indicated by the presence of the Pαβ (21e8) and Pαγ (21e6) methyl sites at 17.7 and 17.2 ppm and confirmed by other characteristic signals.

[0205] The total amount of secondary (2,1-erythro) inserted propene was quantified based on the αα21e9 methylene site at 42.4 ppm:

P21=Iαα21e9

[0206] The total amount of primary (1,2) inserted propene was quantified based on the main δαα methylene sites at 46.7 ppm and compensating for the relative amount of 2,1-erythro, αB4 and ααB4B4 methylene unit of propene not accounted for (note H and HH count number of hexene monomers per sequence not the number of sequences):

P12=I.sub.sαα+2*P21+H+HH/2

[0207] The total amount of propene was quantified as the sum of primary (1,2) and secondary (2,1-erythro) inserted propene:

Ptotal=P12+P21=I.sub.sαα+3*Iαα21e9+(IαB4−2*IααB4)/2+IααB4

[0208] This simplifies to:

Ptotal=I.sub.sαα+3*Iαα21e9+0.5*IαB4

[0209] The total mole fraction of 1-hexene in the polymer was then calculated as:

fH=Htotal/(Htotal+Ptotal)

The full integral equation for the mole fraction of 1-hexene in the polymer was:

fH=(((IαB4−2*IααB4)/2)+(2*IααB4))/((I.sub.sαα+3*Iαα21e9+0.5*IαB4)+((IαB4−2*IααB4)/2)+(2*IααB4))

[0210] This simplifies to:

fH=(IαB4/2+IααB4)/(I.sub.sαα+3*Iαα21e9+IαB4+IααB4)

[0211] The total comonomer incorporation of 1-hexene in mole percent was calculated from the mole fraction in the usual manner:

H[mol %]=100*fH

[0212] The total comonomer incorporation of 1-hexene in weight percent was calculated from the mole fraction in the standard manner:

H[wt %]=100*(fH*84.16)/((fH*84.16)+((1−fH)*42.08))

[0213] Calculation of comonomer content of the second random propylene copolymer (B):

[00002]$\frac{C\left(\mathrm{CPP}\right)-w\left(A\right)\times C\left(A\right)}{w\left(B\right)}=C\left(B\right)$

[0214] wherein [0215] w(A) is the weight fraction of the first random propylene copolymer (A), [0216] w(B) is the weight fraction of the second random propylene copolymer (B), [0217] C(A) is the comonomer content [in wt.-%] measured by .sup.13C NMR spectroscopy of the first random propylene copolymer (A), i.e. of the product of the first reactor (R1), [0218] C(CPP) is the comonomer content [in wt.-%] measured by .sup.13C NMR spectroscopy of the product obtained in the second reactor (R2), i.e. the mixture of the first random propylene copolymer (A) and the second random propylene copolymer (B) [of the propylene copolymer (C-PP)], [0219] C(B) is the calculated comonomer content [in wt.-%] of the second random propylene copolymer (B).

[0220] B. Materials Used

[0221] Component A)

[0222] Polymer Blend (Dipolen S)

[0223] Dipolen S is a recycled polymer mixture comprising polyethylene and polypropylene obtained from mtm plastics GmbH, Niedergebra, Germany and has a polyethylene content of 40 wt.-% determined by DSC analysis. The melting points determined by DSC were 162° C. (PP) and 128° C. (PE).

[0224] Polypropylene (HD800CF)

[0225] Bormed™ HD800CF is a polypropylene homopolymer obtainable from Borealis AG (MFR 230° C./2.16 kg=8 g/10 min).

[0226] HDPE (MB6561)

[0227] BorPure™ MB6561 is a bimodal, high-density polyethylene obtainable from Borealis AG (density: 956 kg/m.sup.3, MFR 190° C./2.16 kg=1.5 g/10 min).

[0228] LDPE (FT5230)

[0229] Polyethylene FT5230 is a low-density polyethylene obtainable from Borealis AG (density: 923 kg/m.sup.3, MFR 190° C./2.16 kg=0.75 g/10 min).

[0230] Component B)

[0231] Copolymer of Propylene and 1-Hexene (C3C6)

[0232] The copolymer of propylene and 1-hexene “C3C6” was prepared in a sequential process comprising a prepolymerisation reactor, a loop reactor and a gas phase reactor. The catalyst used for manufacturing the copolymer of propylene and 1-hexene “C3C6” was prepared as described in detail in WO 2015/011135 A1 (metallocene complex MC1 with methylaluminoxane (MAO) and borate resulting in Catalyst 3 described in WO 2015/011135 A1) with the proviso that the surfactant is 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoro-propoxy)-1-propanol. The metallocene complex (MC1 in WO 2015/011135 A1) is prepared as described in WO 2013/007650 A1 (metallocene E2 in WO 2013/007650 A1). The specific reaction conditions are summarized in Table 1.

TABLE-US-00001 TABLE 1 Preparation of C3C6. Prepolymerisation reactor Temperature [° C.] 20 Pressure [kPa] 5238 C3 feed [kg/h] 60.7 H2 [g/h] 0.5 Loop reactor Temperature [° C.] 70 Pressure [kPa] 5292 Feed H2/C3 ratio [mol/kmol] 0.08 Feed C6/C3 ratio [mol/kmol] 10.7 Polymer residence time [h] 0.6 Polymer Split [wt.-%] 42.0 MFR2 [g/10 min] 1.8 Total C6 [wt.-%] 1.7 XCS [%] 1.9 Gas phase reactor Temperature [° C.] 80 Pressure [kPa] 2406 Feed H2/C3 ratio [mol/kmol] 0.8 Feed C6/C3 ratio [mol/kmol] 9.2 Polymer residence time [h] 2.6 Polymer split [wt.-%] 58.0 MFR2 [g/10 min] 1.4 MFR2(b2) [g/10 min] 1.2 Total C6 [wt.-%] 5.5 C6(b2) [wt.-%] 8.2 XCS [%] 26.9 C6(XCS) [wt.-%] 7.2 Pellet MFR2 [g/10 min] 1.4 Tc [° C.] 101 Tm [° C.] 135

[0233] Further Components

[0234] Plastomer (Queo 8201)

[0235] Queo 8201 is an ethylene-based octene plastomer available from Borealis AG (density: 882 kg/m.sup.3, MFR 190° C./2.16 kg=1.1 g/10 min).

[0236] Antioxidant (AO)

[0237] AO is a 1:2-mixture of Pentaerythrityl-tetrakis(3-(3′,5′-di-tert. butyl-4-hydroxyphenyl)-propionate, CAS-no. 6683-19-8, and Tris(2,4-di-t-butylphenyl) phosphite, CAS-no. 31570-04-4), commercially available from BASF AG (DE) as Irganox B215.

[0238] Additive Carrier (PP-H)

[0239] PP-H is the commercial unimodal propylene homopolymer HC001A-B1 of Borealis AG having a melt flow rate MFR2 (230° C.) of about 2 g/10 min and a Tm of 160° C.

[0240] C) Preparation of the Polymer Compositions

[0241] The polymer compositions according to the inventive examples (IE1 to IE3) and the comparative examples (CE1 to CE4) were prepared on a Coperion ZSK 25 co-rotating twin-screw extruder equipped with a mixing screw configuration with an L/D ratio of 25. A melt temperature of 200 to 220° C. was used during mixing, solidifying the melt strands in a water bath followed by strand pelletization. The amounts of the different components in the polymer compositions and the properties of the polymer compositions according to the inventive examples and the comparative examples can be gathered from below Table 2.

TABLE-US-00002 TABLE 2 Composition and properties of the polymer compositions. Unit IE1 IE2 IE3 CE1 CE2 CE3 CE4 Component Dipolen S (A) wt.-% 88 — — 100 93 — — HD800CF (A) wt.-% — 75 75 — — 85 85 MB6561 (A) wt.-% — 15 — — — 15 — FT5230 (A) wt.-% — — 15 — — — 15 C3C6 (B) wt.-% 10 10 10 — — — — Queo 8201 wt.-% — — — — 5 — — AO wt.-% 0.1 — — — 0.1 — — PP-H wt.-% 1.9 — — — 1.9 — — Properties MFR2 g/10 min 4.01 6.6 7.2 7.5 4.8 7.9 7.9 Tm(PE) ° C. 128 130 111 128 127 129 111 Tm(PP) ° C. 159 163 163 162 161 163 163 Hm(PE) J/g 65 49 25 59 63 48 24 Hm(PP) J/g 43 71 84 49 43 80 86 Hm(PE)/Hm(PP) — 1.51 0.69 0.30 1.20 1.47 0.60 0.28 Tc(PE) ° C. 115 n.d. 99 117 115 n.d. 99 Tc(PP) ° C. 121 118 119 123 123 117 114 Tensile Modulus MPa 928 n.d. n.d. 980 886 n.d. n.d. Tensile Strength MPa 23 n.d. n.d. 23 21 n.d. n.d. Flexural Modulus % n.d. 1445 1295 n.d. n.d. 1575 1319 Elong. at break % 423 n.d. n.d. 110 361 n.d. n.d. Charpy NIS 23° C. kJ/m.sup.2 8.5 3.5 3.9 6.5 7.2 3.2 3.2 n.d. = not determined.

[0242] D) Discussion of the Results

[0243] Since the same polymer was used, the polymer composition according to IE1 can be compared with the polymer compositions according to CE1 and CE2, the polymer composition according to 1E2 is comparable to the polymer composition according to CE3 and the polymer composition according to 1E3 can be compared with the polymer composition according to CE4.

[0244] As can be gathered from Table 2, the polymer compositions according to the inventive examples show a higher toughness, expressed by the Charpy Notched Impact Strength at 23° C., than the polymer compositions according to the Comparative Examples. The stiffness, expressed by the Tensile Modulus or the Flexural Modulus, of the polymer compositions in accordance with the solution is on the same level than the stiffness of the polymer compositions according to the Comparative Examples.

[0245] The comparison of the polymer compositions according to IE1 and CE2 shows that plastomers are less suited as modifiers for improving the toughness of a polymer composition while maintaining the stiffness, than component B) according to the solution. From the experimental results can be seen that only the specific combination of features as described herein allows to obtain polymer compositions having an excellent toughness and a good stiffness. It is remarkable that the effect of component B) to improve the toughness of a polymer composition is more pronounced in recycled materials than in virgin polymers (see IE1 vs. 1E2 and 1E3).