USE OF A COMPOSITION FOR THE MANUFACTURE OF A FOAMED ARTICLE

Abstract

The present invention relates to the use of a composition comprising from 60-98 wt. % of polypropylene, from 2-40 wt. % of aromatic polycarbonate and from 0.1-10 wt. % of compatibiliser for the manufacture of a foamed article, wherein the compatibiliser is a BAB or AB type of block copolymer comprising a polypropylene block A and a polyester or polycarbonate block B, or wherein the compatibiliser is a graft copolymer of the type ABn having a polypropylene backbone A and polyester or polycarbonate block(s) B grafted thereon, with n being at least 1, and wherein the polyester or polycarbonate blocks B have an average M/F ratio from 2-25, wherein M is the number of backbone carbon atoms in the polyester or polycarbonate not including carbonyl carbon atoms, and F is the number of ester or carbonate groups in the polyester or polycarbonate block, and wherein the wt. % is based on the sum of the amount polypropylene, polycarbonate and compatibiliser.

Claims

1. A composition comprising 60-98 wt. % of polypropylene 2-40 wt. % of aromatic polycarbonate 0.1-10 wt. % of compatibiliser wherein the compatibiliser is a BAB or AB type of block copolymer comprising a polypropylene block A and (a) polyester or polycarbonate block(s) B, or wherein the compatibiliser is a graft copolymer of the type ABn having a polypropylene backbone A and polyester or polycarbonate block(s) B grafted thereon, with n being at least 1, and the polyester or polycarbonate block(s) B have an average M/F ratio from 2-25, wherein M is the number of backbone carbon atoms in the polyester or polycarbonate not including carbonyl carbon atoms, and F is the number of ester or carbonate groups in the polyester or polycarbonate block(s), wherein the wt. % is based on the sum of the amount polypropylene, polycarbonate and compatibilizer.

2. The composition of claim 1 wherein the M/F ratio is from 2-10.

3. The composition of claim 1 wherein the amount of compatibiliser is from 1-8 wt. %.

4. The composition claim 1 wherein in the compatibiliser block(s) B is/are a polyester.

5. The composition of claim 1 wherein in the compatibiliser the polypropylene block or backbone A is a propylene homopolymer or a random propylene and ethylene or C.sub.4-C.sub.8 alpha olefin copolymer containing at most 5 wt. %, on the basis of the weight of the backbone, of ethylene or C.sub.4-C.sub.8 alpha olefin.

6. The composition of claim 1 wherein the polypropylene is a propylene homopolymer or a random propylene and ethylene or C.sub.4-C.sub.8 alpha olefin copolymer containing at most 5 wt. %, on the basis of the weight of the polypropylene, of said ethylene or a C.sub.4-C.sub.8 alpha olefin.

7. The composition of claim 1 wherein the amount of polypropylene is at least 70 wt. % and the amount of aromatic polycarbonate is from 5-20 wt. %.

8. A method forming a foamed article comprising foaming the composition according to claim 1 in a direct extrusion foaming process.

9. An article foamed from the composition of claim 1 having a percentage of closed cells of at least 50% as determined in accordance with ASTM D2856.

10. The foamed article of claim 9, wherein the foamed article has a degree of expansion of from 1.05-40, wherein the degree of expansion is defined as the ratio between the density of the composition in molded state prior to foaming and the density of the foamed composition after foaming.

11. A foamed article comprising or consisting of the composition as defined in claim 1 and optionally residues of a chemical or physical foaming agent.

12. A method for the manufacture of a foamed article comprising the steps of i) providing a composition comprising 60-98 wt. % of polypropylene 2-40 wt. % of aromatic polycarbonate 0.1-10 wt. % of compatibiliser wherein the compatibiliser is a BAB or AB type of block copolymer comprising a polypropylene block A and (a) polyester or polycarbonate block(s) B, or wherein the compatibiliser is a graft copolymer of the type ABn having a polypropylene backbone A and polyester or polycarbonate block(s) B grafted thereon, with n being at least 1, and the polyester or polycarbonate block(s) have an average M/F ratio from 2-25, wherein M is the number of backbone carbon atoms in the polyester or polycarbonate not including carbonyl carbon atoms, and F is the number of ester or carbonate groups in the polyester or polycarbonate block(s), wherein the wt. % is based on the sum of the amount polypropylene, polycarbonate and compatibiliser, ii) adding to said composition a physical or chemical foaming agent, iii) foaming the composition of step ii into a foamed article.

13. The method of claim 12 further comprising adding the foaming agent to the composition in an extruder and mixing the composition in molten state.

14. The method of claim 12 wherein the blowing agent is a physical foaming agent and wherein the method comprises extruding the composition through a die to form the foamed article.

15. The method of claim 11 wherein the foaming agent is a chemical foaming agent and wherein the method comprises first molding the composition of step ii) into a unfoamed intermediate article, and then foaming said unfoamed intermediate.

16. A composition comprising 60-98 wt. % of polypropylene 2-40 wt. % of aromatic polycarbonate 0.1-10 wt. % of compatibiliser a chemical foaming agent wherein the compatibiliser is a BAB or AB type of block copolymer comprising a polypropylene block A and (a) polyester or polycarbonate block(s) B, or wherein the compatibiliser is a graft copolymer of the type ABn having a polypropylene backbone A and polyester or polycarbonate block(s) B grafted thereon, with n being at least 1, and the polyester or polycarbonate block(s) B have an average M/F ratio from 2-25, wherein M is the number of backbone carbon atoms in the polyester or polycarbonate not including carbonyl carbon atoms, and F is the number of ester or carbonate groups in the polyester or polycarbonate block(s), wherein the wt. % is based on the sum of the amount polypropylene, polycarbonate and compatibiliser.

Description

EXAMPLES

[0147] Materials

[0148] ε-Caprolactone (CL) (97%, Sigma-Aldrich), w-Pentadecalactone (PDL) (98%, Sigma-Aldrich) and ethylene brassylate (EB) (>95% Sigma-Aldrich) were dried over CaH.sub.2 and distilled under reduced pressure. Exxelor P01020 was purchased from ExxonMobil. Methanol, pentamethyl heptane (from in house purification system) were used as received. Toluene (anhydrous, Sigma-Aldrich) and tetrahydrofuran (THF) (anhydrous, Sigma-Aldrich) were purified using an MBraun-SPS-800 purification column system and were kept in glass bottle with 4-A molecular sieves under an inert atmosphere. 10-undecen-1-ol, ethanolamine and tin(II) 2-ethylhexanoate were purchased from Sigma-Aldrich. Methylaluminoxane (MAO) (30 wt. % solution in toluene) was purchased from Chemtura. Diethyl zinc (DEZ) (1.0 M solution in hexanes), triisobutylaluminum (TiBA) (1.0 M solution in hexanes), di-n-butylmagnesium (MgBu.sub.2, 1.0 M solution in heptane), and 2,6-di-tert-butyl-4-methylphenol (BHT) (99%, purum), were purchased from Sigma-Aldrich. rac-Me.sub.2Si(2-Me-4-Ph-Ind).sub.2ZrCl.sub.2 was purchased from MCAT GmbH, Konstanz, Germany.

[0149] PP531 is a semi-crystalline propylene homopolymer commercially available from SABIC having a melt flow rate of 0.30 g/10 min (ISO 1133, 2.16 kg, 230° C.).

[0150] PP500 is a semi-crystalline propylene homopolymer commercially available from SABIC having a melt flow rate of 3.1 g/10 min (ISO 1133, 2.16 kg, 230° C.).

[0151] PP108 is a heterophasic polypropylene commercially available from SABIC having a melt flow rate of 10 g/10 min (ISO 1133, 2.16 kg, 230° C.).

[0152] PC105 is a linear polycarbonate homopolymer commercially available from SABIC and having a melt flow rate of 7 g/10 min (ASTM D 1238, 1.2 kg, 300° C.).

[0153] PC115 is a linear polycarbonate homopolymer having a melt flow rate of 60 g/10 min (ASTM D 1238, 1.2 kg, 300° C.).

[0154] Daploy WB140, commercially available from Borealis, is a high melt strength propylene homopolymer having a melt flow rate of 2.1 g/10 min in accordance with ISO 1133 (230° C. and 2.16 kg).

[0155] ExxelorPO1020, commercially available from ExxonMobil, is a maleic anhydride-grafted propylene homopolymer having a melt flow rate of 430 g/10 min in accordance with ISO 1133 (230° C. and 2.16 kg).

[0156] Measurement Methods

[0157] Conversion of Reactions was Determined by NMR:

[0158] .sup.1H NMR analysis (.sup.1H-NMR) carried out at 80-110° C. using deuterated tetrachloroethane (TCE-d.sub.2) as the solvent and recorded in 5 mm tubes on a Varian Mercury spectrometer operating at frequencies of 400 MHz. Chemical shifts in ppm versus TCE-d.sub.2 were determined by reference to the residual solvent signal.

[0159] M.sub.n, M.sub.W and the polydispersity index (PDI, Ð.sub.M) were determined as follows by size exclusion chromatography:

[0160] SEC measurements were performed at 150° C. on a Polymer Char GPC-IR® built around an Agilent GC oven model 7890, equipped with an autosampler and the Integrated Detector IR4. 1,2-dichlorobenzene (oDCB) was used as an eluent at a flow rate of 1 mL/min. The SEC-data were processed using Calculations Software GPC One®. The molecular weight was determined on the basis of polystyrene standards.

[0161] Melting (T.sub.m) and crystallisation (T.sub.c) temperatures as well as enthalpies of the transitions, melting and crystallisation peaks, were measured by differential scanning calorimetry (DSC) using a DSC Q100 from TA Instruments. The measurements were carried out at a heating and cooling rate of 10° C..Math.min.sup.−1 from −60° C. to 210° C. The transitions were deduced from the second heating and cooling curves.

[0162] Density analysis were carried out using PLT-A01 set for density determination available from KERN. The foam samples were immersed in water to determine the volume and the mass by weighing it on the balance. The volume determination is based on the Law of Archimedes.

[0163] The morphology of foam cell structures was determined with a JEOL JSM 7800-F Field Emission Scanning Electron Microscopy (FE-SEM) at an operating voltage of 5 kV. A piece of foam sample were cryogenically cut using an ultra sharp razor blade for the cross-sectional morphology characterisation. The foam cross section was viewed using the Large Depth of Focus (LDF) mode and the Lower Electron Detector (LED) detector in the FE-SEM. The LDF mode provides a larger depth of focus than conventional SEM mode, and is suitable for imaging of rough samples with micron size features. All the samples were sputter-coated with gold-palladium before SEM imaging in order to reduce the surface charging during imaging.

[0164] Uniaxial elongational flow using an extensional viscosity fixture measurement was conducted on an ARES rheometer at 160° C. under several elongational rates between 0.05 and 0.5 s.sup.−1. The rectangular specimens with dimensions of 15 mm×10 mm×0.9 mm were fabricated by a compression molding at 210° C. under 100 kN in the hot press machine.

[0165] Typical Procedure for the Synthesis of Hydroxyl Functionalised Polypropylene Via Reactive Extrusion (REX):

[0166] iPP-g-MAH (ExxelorPO1020: 0.43 wt. % maleic anhydride (MAH), 10.0 g, M.sub.n=22 kg.Math.mol.sup.−1, Ð=4.4) with antioxidant (2500 ppm) was introduced into a co-rotating twin-screw extruder under nitrogen atmosphere set with different temperature zones 50-90-160-165-170-170-180-180° C., respectively. Than ethanolamine was added to the extruder. The amount of ethanolamine was calculated according to the content of anhydride groups in ExxelorPO1020 (molar ratio of ethanolamine:anhydride was equal to 1.1:1). The mixture was processed and then cooled and granulated. The product was dried in a vacuum oven for 10 h at 70° C.

[0167] Typical Procedure for the Synthesis of Hydroxyl Functionalised Polypropylene Via Catalytic Route:

[0168] Polymerisation experiments were carried out in a stainless steel autoclave with an internal volume of 2.1 L. The reactor is equipped with interMIG stirrer, operated at 900 rpm. Pentamethyl heptane (PMH, 400 mL), was added into the autoclave. Propylene (typically 200 NI/h) was dosed via Brooks Mass flow controller into the headspace and the propylene was set at the desired pressure (9 bar). The temperature was set at 87° C. Off-gas was continuously vented. Subsequently, the MAO (30 wt. % solution in toluene, 9 mmol) was dosed using the injection vessel with an additional 400 mL of PMH. After stirring the mixture for 15-20 min at 87° C., a premixed solution of 10-undecen-1-ol and TiBA (TiBA/C11=OH=1, 0.85 M, 10 mL), DEZ (1 M solution in hexane, 1 mL) and TiBA (1 M solution in hexane, 4 mL) were introduced into the reactor under a nitrogen atmosphere with PMH through the injection Schlenk vessel. The mixture was stirred for 10 min and a solution of rac-dimethylsilyl bis(2-methyl-4-phenyl-1-indenyl) zirconium dichloride catalyst (6 μmol) in approximately 5 mL of toluene was injected into the reactor applying an over pressure of nitrogen. After dosing all the components, the total volume of the added PMH was 1 L. The reactor temperature was kept at 87±3° C. by cooling with an oil LAUDA system. At the end of the reaction (20 min), the mixture was drawn off via a bottom valve. A mixture of acidified methanol (2.5% v/v HCl) and Irganox 1010 was added and the resulting suspension was filtered, washed with demineralised water and dried at 60° C. in vacuo overnight.

[0169] Synthesis of Mg(BHT).sub.2(THF).sub.2Catalyst. (FIG. 1a)

[0170] In the glovebox, 2,6-di-tert-butyl-4-methylphenol (BHT, 4.40 g, 0.20 mmol) was introduced into Schlenk glass and dissolved in dry tetrahydrofuran (30 mL). The mixture was cooled down to 0° C. in an ice bath. Subsequently n-Bu.sub.2Mg (3.89 ml of 1 M solution in hexane, 20 mmol of n-Bu.sub.2Mg) was added to BHT solution in THE and stirred at room temperature for 24 h under nitrogen atmosphere. The solvent was removed under reduced pressure. A white powder was rinsed with dry heptane (3×15 mL) and dried under reduced pressure. Yield: 4.41 g (73.3%).

[0171] Synthesis of Na.sub.3(BHT).sub.3(THF).sub.3Catalyst. (FIG. 1b)

[0172] A mixture of 2,6-di-tert-butyl-4-methylphenol (8.8 g, 40 mmol) and NaH (1.00 g, 42 mmol) was stirred in tetrahydrofuran (30 mL) at room temperature for 24 h. After the reaction, a residual NaH was removed by filtration while the solvent was removed under reduced pressure. Thus obtained white powder was washed with heptane (3×15 mL) and dried in vacuo. Yield: 8.81 g (70.1%).

[0173] Synthesis of Aluminum-Salen Complex (FIG. 1c)

[0174] N,N′-bis(salicylidene)ethylenediamine (2.0 g, 7.5 mmol) was suspended in toluene (30 mL) under N.sub.2 flow. Subsequently, Al(CH.sub.3).sub.3 (2 M solution in toluene, 3.75 mL, 7.5 mmol) was added via syringe and the mixture was stirred at room temperature for 1 h. The thus obtained solution was concentrated to half the original volume and pale yellow needles were isolated with a yield of 93%.

[0175] Synthesis of Aluminum-Salpen Type Complex (FIG. 1d)

[0176] N,N′-bis(salicylidene)-2,2-dimethyl-1,3-propanediamine (2.0 g, 5.7 mmol) was suspended in toluene (30 mL) under N.sub.2 flow. Subsequently, Al(CH.sub.3).sub.3 (2 M solution in toluene, 2.85 mL, 5.7 mmol) was added via syringe and the mixture was stirred at room temperature for 1 h. The thus obtained solution was concentrated to half the original volume and pale yellow crystals were isolated with a yield of 88%.

[0177] Typical Procedure for the Synthesis of PP-Graft-PCL Via Transesterification:

[0178] The experiments were carried out in a co-rotating twin-screw extruder at 40-120-165-170-180-180-180-180-170-155-150° C. with a screw rotation speed of 65 rpm and throughput 3 kg/hr. Hydroxyl-functionalised polypropylene (PP-OH, M.sub.n=36200 g/mol, M.sub.w=166000 g/mol, Ð.sub.M=4.59 1995 g), polycaprolactone (PCL, 990 g, M.sub.n=4600 g/mol, M.sub.w=21900 g/mol, Ð.sub.M=4.7, M/F=5/1) and stannous octoate as catalyst (Sn(Oct).sub.2, 15 g) were fed into the extruder. The process of extrusion was carried out using two feeders.

[0179] From the first feeder PP-OH and from the second—blend of the other components were dosed. The mixture was processed and then cooled and granulated. The copolymer was dried in a vacuum oven for 10 h at 70° C. The conversion of the hydroxyl-functionalised polypropylene was 63% and M.sub.w of the copolymer 103.2 kg/mol.

[0180] The copolymers PP-graft-PCL 120, PP-graft-PCL 140, PP-graft-PCL 150, PP-graft-PCL 170, PP-graft-PCL 242 were prepared using PP-OH obtained by REX from ExxelorPO1020 and PCL with M.sub.w=120 kg/mol, 140 kg/mol, 150 kg/mol, 170 kg/mol, 242 kg/mol, using the same processing conditions.

[0181] Typical Procedure for the Synthesis of PP-Graft-PCL Via Catalytic Ring-Opening Polymerisation:

[0182] In the glovebox, catalyst (BHT).sub.2Mg(THF).sub.2 (400 mg, 0.659 mmol, M.sub.w=607 g/mol), an equimolar amount of PP-graft-C.sub.11OH (0.372 mmol, 9.45 g, mass was calculated in relation to the number of hydroxyl groups in polymer chain from .sup.1H NMR, M.sub.n=25400 g/mol, Ð.sub.M=2.42, 1.77 gr OH/macromolecule) were placed in the reactor. Dry toluene was added (112.5 g). The mixture was removed from the glovebox and put in the oil bath at 115° C. to perfectly dissolve catalyst and polypropylene. After that, the monomer (dry caprolactone) (42.5 g, 0.372 mol) was added. The reaction was carried out at 115° C. for 5 hours. A mixture of acidified methanol (2.5% v/v HCl) and Irganox 1010 was added and the resulting suspension was filtered, washed with methanol and dried at 50° C. in vacuo overnight. The yield of the reaction was 97% and M.sub.w of the copolymer 239.2 kg/mol.

[0183] Typical Procedure for the Synthesis of PP-Block-PPDL Via Catalytic Ring-Opening Polymerisation

[0184] A glass crimp cap vial was charged with toluene (1.5 mL), PDL (1.08 g, 4.5 mmol, M/F=14), hydroxyl end-capped iPP (17.4 mg, 8.7 μmol) and aluminum salpen catalyst (3.05 mg, 8.7 μmol). All manipulations were carried out in the glovebox. Then, the mixture was removed from the glovebox and stirred in an oil bath at 100° C. The progress of the reaction was followed by .sup.1H NMR spectroscopy by taking aliquots at set time intervals. The synthesized copolymer was cooled to room temperature and quenched using acidified methanol, isolated and dried in vacuum at room temperature for 18 h. The yield of the reaction was 93% and the M.sub.w of the copolymer 176 kg/mol.

[0185] Typical Procedure for the Synthesis of PP-Graft-PPDL Via Catalytic Ring-Opening Polymerisation:

[0186] A glass crimp cap vial was charged with toluene (1.5 mL), PDL (1.1 g, 4.5 mmol, M/F=14), hydroxyl-functionalised PP (4.9 mg, 8.7 μmol) and aluminium salen catalyst (˜3.05 mg, 8.7 μmol). All manipulations were carried out in the glovebox. Then, the mixture was removed from the glovebox and stirred in an oil bath at 100° C. The progress of the reaction was followed by .sup.1H NMR spectroscopy by taking aliquots at set time intervals. The synthesized copolymer was cooled to room temperature and quenched using acidified methanol, isolated and dried in vacuum at room temperature for 18 h. The yield of the reaction was 96% and M, of the copolymers 107 kg/mol.

[0187] Typical Polymerisation Procedure of EB Via Catalytic Ring-Opening Polymerisation:

[0188] In a glovebox, benzyl alcohol (0.40 mg, 3.7 μmol), Na.sub.3(BHT).sub.3(THF).sub.3 catalyst (1.16 mg, 1.23 μmol) and ethylene brassylate (500 mg, 1.85 mmol, M/F=(11+2)/2=6.5) were introduced into a small glass crimp cap vial and the vial was capped. The reaction mixture was removed from the glovebox and stirred for 3 h in a carrousel reactor at 200° C. For all reactions, an aliquot of crude polymer was withdrawn at the end of the polymerisation reaction in order to determine the conversion of the monomers by H NMR spectroscopy. The reaction was then stopped by quenching the crude product with acidified methanol (5 mL). The polymer was isolated and dried at 40° C. for 24 h under reduced pressure. The yield of the reaction was 94% and M.sub.w of the copolymer 96 kg/mol.

[0189] Typical Procedure for the Synthesis of PP-Block-PEB Copolymers Via Transesterification reaction:

[0190] Chain-end hydroxyl-functionalised isotactic PP (1, 6.0 g, M.sub.n=14.3 kg/mol, Ð.sub.M=1.9) and PEB (3.0 g, M.sub.n=40.9 kg/mol, Ð.sub.M=2.7, M/F=(11+2)/2=6.5) with antioxidant Irganox 1010 (2500 ppm) were fed into a co-rotating twin-screw mini-extruder at 160° C. with a screw rotation rate set at 100 rpm. The polymers were premixed for 5 minutes. After this time tin (II) 2-ethylhexanoate (0.09 g, 0.22 mmol) as catalyst was added and the mixture was stirred for an additional 5 minutes. Afterwards the extruder chamber was cooled and evacuated. The yield of the reaction was 73% and the M.sub.w of the product 91 kg/mol.

[0191] Typical Procedure for Preparation of PP/PC Blends:

[0192] 800 g of PP (PP 500P, MFR=3.1 g/10 min (230° C./2.16 kg)) and 200 g of PC (PC105, MFR=7 g/10 min (300° C./1.2 kgf)) with Irganox1010 (12.5 g) were fed into a co-rotating twin-screw extruder. The mixture was processed at 40-180-210-230-240-240-240-230-200-190-180° C. with a screw rotation speed of 60 rpm and throughput 2.5 kg/hr. The process of extrusion was carried out using two feeders. The mixture was processed and then cooled and granulated. The blend was dried in a vacuum oven for 10 h at 70° C. and investigated in terms of its morphology, static mechanical properties and surface properties.

[0193] Typical Procedure for Preparation of PP/PC Blends Compatibilised by PP-Graft-PCL copolymer:

[0194] 770 g of PP (PP 500P, MFR=3.1 g/10 min (230° C./2.16 kg)) and 180 g of PC (PC105, MFR=7 g/10 min (300° C./1.2 kgf)) with Irganox1010 (12.5 g) and 50 g of PP-graft-PCL were fed into a co-rotating twin-screw extruder. The mixture was processed at 40-180-210-230-240-240-240-230-200-190-180° C. with a screw rotation speed of 60 rpm and throughput 2.5 kg/hr. The process of extrusion was carried out using two feeders. From the first feeder PP and from the second—blend of the other components were introduced.

[0195] The mixture was processed and then cooled and granulated. The blend was dried in a vacuum oven for 10 h at 70° C. and investigated in terms of its morphology, static mechanical properties and surface properties.

[0196] The procedure above was followed for all blends reported in Tables 1 and 2 below with the corresponding materials and amounts as indicated in Tables 1 and 2 below.

[0197] The nature of the copolymers and the composition of the blends for the foam according to the invention is shown in Tables 1 and 2 below.

TABLE-US-00001 TABLE 1 PP-graft-PCL PP- Entry M.sub.n M.sub.w graft- REX (PP-PCL) [kg .Math. mol.sup.−1] [kg .Math. mol.sup.−1] PP PC PP/PC PCL 1 PP-graft-PCL21.9 13.0 103.2 PP531 PC105 87/8  5 2 PP-graft-PCL21.9 13.0 103.2 PP531 PC105 77/18 5 3 PP-graft-PCL21.9 13.0 103.2 PP531 PC115 87/8  5 4 PP-graft-PCL21.9 13.0 103.2 PP531 PC115 77/18 5 5 PP-graft-PCL21.9 13.0 103.2 PP500 PC105 87/8  5 6 PP-graft-PCL21.9 13.0 103.2 PP500 PC105 77/18 5 7 PP-graft-PCL120.sup.+ 28.5 115.2 PP500 PC105 77/18 5 8 PP-graft-PCL140 30.0 104.3 PP500 PC105 77/18 5 9 PP-graft-PCL150 18.4 99.7 PP500 PC105 77/18 5 10 PP-graft-PCL170 26.4 100.5 PP500 PC105 77/18 5 11 PP-graft-PCL242 25.7 90.5 PP500 PC105 77/18 5 12 PP-graft-PCL21.9 13.0 103.2 PP108MF10 PC115 77/18 5

TABLE-US-00002 TABLE 2 PP-OH PP-graft-PCL PP- Entry M.sub.w M.sub.n M.sub.w graft- ROP(ss-PP-PCL) [kg .Math. mol.sup.−1] [kg .Math. mol.sup.−1] [kg .Math. mol.sup.−1] PP PC PP/PC PCL 13 PP-graft-PCL 61.5 61.2 239.2 PP500 PC105 87/8  5 14 PP-graft-PCL.sup.+ 61.5 61.2 239.2 PP500 PC105 77/18 5 15 PP-graft-PCL 61.5 61.2 239.2 PP500 PC105 77/18 3 16 PP-graft-PCL 61.5 61.2 239.2 PP500 PC105 77/18 10 17 PP-graft-PCL 61.5 61.2 239.2 PP531 PC105 87/8  5 18 PP-graft-PCL 61.5 61.2 239.2 PP530 PC105 77/18 5 19 PP-graft-PCL 61.5 61.2 239.2 PP531 PC115 87/8  5 20 PP-graft-PCL 61.5 61.2 239.2 PP530 PC115 77/18 5 21 PP-graft-PCL 61.5 19.1 150.6 PP500 PC105 87/8  5 22 PP-graft-PCL 61.5 19.1 150.6 PP500 PC105 77/18 5 23 PP-graft-PCL 61.5 19.1 150.6 PP500 PC105 77/18 3 24 PP-graft-PCL 61.5 19.1 150.6 PP500 PC105 77/18 10 25 PP-graft-PCL 61.5 19.1 150.6 PP531 PC105 87/8  5 26 PP-graft-PCL 61.5 19.1 150.6 PP530 PC105 77/18 5 27 PP-graft-PCL 61.5 19.1 150.6 PP531 PC115 87/8  5 28 PP-graft-PCL 61.5 19.1 150.6 PP530 PC115 77/18 5 29 PP-graft-PCL 61.5 19.1 150.6 PP108 PC115 87/8  5 30 PP-graft-PCL 61.5 19.1 150.6 PP108 PC115 77/18 5

[0198] Foaming experiments were performed on a lab scale foaming unit consisting on an 11 mm co-rotating twin screw extruder for melting the polymer composition and injection of the physical foaming agent iso-butane. The outlet of the extruder is directly fed into a static mixer consisting of three zones (entrance zone, mixer zone and tool zone) for further mixing the foaming agent with the molten polymer composition and controlling of the temperature. The amount of polymer composition fed to the extruder was 290 g/h and the amount of iso-butane that was dosed in the extruder was kept at a constant value of 28.4 g/hr. At the start of the experiment the mixer and tool zone temperatures were set at 200° C. During the experiments the temperatures of the mixer and tool zones were lowered in steps of 5-10° C. each time allowing five minutes for stabilisation of the process at each temperature setting. Once the temperatures were stabilised the tool zone pressure was set at 30 bars by adjusting the opening of the die. Initial settings of the foaming unit are per the Table 3 below.

TABLE-US-00003 TABLE 3 Extruder Screwspeed [rpm] 75 T1 ° C. 80 T2 ° C. 160 T3 ° C. 210 T4 ° C. 210 T5 ° C. 210 T6 ° C. 210 T7 ° C. 210 T8 ° C. 210 Static mixer T_entrance ° C. 200 T_mixer ° C. 200 T_Tool ° C. 200 P_Tool Bar 30 Foaming die Temperature ° C. 200

[0199] T1-T8 are the temperatures of the sections 1-8 of the extruder.

[0200] FIG. 1 shows examples of catalyst complexes suitable to realise the invention

[0201] FIG. 2 shows the density of the foams based on: [0202] Entry 10: PP500 (-x), PP500/PC105 compatibilised by PP-graft-PCL copolymer (-•-) [0203] Entry 30: PP108MF10/PC115 compatibilised by PP-graft-PCL copolymer (-.diamond-solid.-) [0204] Daploy WB140 (-.box-tangle-solidup.-) [0205] PP500

[0206] The horizontal axis shows the temperature of the foaming die, while the vertical axis shows the density of the foamed material. The curves essentially show that compositions as disclosed herein can indeed be foamed while the graph also indicates that foaming Entry 30 (based on PP108, a heterophasic polypropylene together with a high flow polycarbonate), is more difficult and only a moderate degree of foaming can be obtained.

[0207] FIG. 3 shows SEM analysis of the foam based on Entry 10 (PP500/PC105 compatibilised by PP-graft-PCL copolymer). The pictures show that the cell walls are predominantly continuous meaning that the foam is predominantly a closed cell foam.

[0208] FIG. 4 shows elongational viscosity as a function of elongational time of the foam based on Entry 10 (PP500/PC105 compatibilised by PP-graft-PCL copolymer) under various Hencky strain rates. The graph shows that upon higher deformation speeds the viscosity increases. This kind of behaviour is favourable for the foaming process and indicative for sufficient melt strength.