Compatibilised polyolefin and polyphenylene oxide and/or polystyrene composition

Abstract

The present invention relates to a composition comprising polyolefin, polyphenylene oxide (PPO) and a compatibiliser, articles made therefrom and the use of a graft or block copolymer as a compatibiliser.

Claims

1. A composition comprising a polyolefin, a polyphenylene oxide (PPO) and optionally polystyrene (PS) and a compatibiliser, wherein said compatibiliser is a block or graft copolymer comprising a polyolefin part and a polystyrene part, wherein the M.sub.n of the polyolefin part is between 1 and 40 kg/mol and the M.sub.n of the polystyrene part is between 4 and 16 kg/mol, wherein further the compatibiliser is present in an amount of between 2 to 20 wt. % of the total amount of the composition, wherein the polyolefin part of the compatibiliser is a propylene homopolymer block or a propylene copolymer block containing at least 90 wt. % of polypropylene, on the basis of the weight of the propylene copolymer block, and wherein the propylene copolymer block is derived from propylene and a comonomer selected from ethylene, a C.sub.4-8 alpha-olefin, or a combination thereof, wherein the amount of the polyolefin is from 50 to 95 wt. % and the amount of the polvphenylene oxide is from 50 to 5 wt. %, each on the basis of the total amount of the polyolefin, the polyphenylene oxide and the optional polystyrene.

2. The composition of claim 1, wherein the amount of the compatibiliser is from 3-17 wt. %, on the basis of the total amount of the composition.

3. The composition of claim 1, wherein the polyolefin is: one or more of a propylene homopolymer, one or more of a propylene--olefin random copolymer, one or more of a propylene--olefin block copolymer, one or more of a hetero-phasic polypropylene copolymer comprising a matrix phase and a disperse phase, the matrix phase consisting of a propylene homopolymer and/or a propylene copolymer with up to 3 wt. % of ethylene and/or at least one C.sub.4-C.sub.8 -olefin, the wt. % being based on the matrix phase, and the disperse phase consisting of an ethylene C.sub.3-C.sub.8 -olefin copolymer, and/or a mixture of any of the foregoing polypropylenes.

4. The composition of claim 1, wherein the polyolefin is a very low density polyethylene, linear low density polyethylene, low density polyethylene, high density polyethylene or a mixture of any of the foregoing polyethylenes.

5. The composition of claim 1, wherein the compatibiliser has a number average molecular weight (M.sub.n) from 10,000 to 40,000 g/mol.

6. The composition of claim 1, wherein the polyolefin part of the compatibiliser has a number average molecular weight (M.sub.n) between 1 and 20 kg/mol.

7. The composition of claim 1, wherein the polystyrene part of the compatibiliser has a number average molecular weight (M.sub.n) between 5 and 15 kg/mol.

8. An article comprising the composition of claim 1.

9. The article of claim 8, said article being selected from the group consisting of automotive parts, electronic devices, parts for electric plugs or contact, parts for batteries or battery cases, and parts for household appliances.

10. The composition of claim 1, wherein said compatibiliser comprises a block or graft copolymer comprising a polyolefin block, and a polystyrene block, wherein the M.sub.n of the polyolefin block is between 1 and 20 kg/mol and the M.sub.n of the polystyrene block is between >5 and <15 kg/mol.

11. The composition of claim 1, wherein the compatibiliseris a block copolymer of type AB with A representing polyolefin and B representing polystyrene.

12. The composition of claim 1, wherein the compatibiliseris is a block copolymer of type BAB with A representing polyolefin and B representing polystyrene.

13. The composition of claim 1, wherein the amount of the polyolefin is from 60 to 90 wt. % and the amount of the polyphenylene oxide is from 10 to 40 wt. %, each on the basis of the total amount of the polyolefin, the polyphenylene oxide and the optional polystyrene.

14. The composition of claim 1, wherein the amount of the polyolefin is from 75 to 85 wt. % and the amount of the polyphenylene oxide is from 15 to 25 wt. %, each on the basis of the total amount of the polyolefin, the polyphenylene oxide and the optional polystyrene.

Description

EXAMPLES

(1) Materials

(2) Chloroform-d [CDCl.sub.3] (VWR, 99.8% D), ethyl -bromoisobutyrate [EtBriBu] (Sigma Aldrich, 98%), ethanol [EtOH] (VWR, 96%), toluene (VWR, 100%), 4-dimethylaminopyridine [DMAP] (Acros Organics, 99%), bromosiobutyrylbromide [BriBuBr] (Acros Organics, 98%), copper(I1)bromide [Cu(II)Br.sub.2] (Sigma Aldrich, 99%), tetrahydrofuran [THF] (Biosolve, 99.8+%), methanol [MeOH] (Acros Organics, 99+%), dimethylformamide [DMF] (Sigma Aldrich, 99.8+%), tin(II)ethylhexanoate [Sn(EH).sub.2] (Sigma Aldrich, 95%);, tris(2-pyridylmethyl)amine [TPMA] (Sigma Aldrich, 98%), anisole (Acros Organics, 99%), dimethyl acetamide [DMA] (Acros Organics, 99%), triethylamine [Et.sub.3N], tetrachloroethane [TCE] (Acros Organics, 99.5%), sodium hypophosphite monohydrate [SoHyp, NaH2PO.sub.2xH.sub.20], iPP hydroxyl-functionalized [iPP-OH] (SABIC, M.sub.n=2500 g/mol, M.sub.n=7700 g/mol); PP (PP525P), PP (PP520P), PS (PS153F) (PPO Noryl 640), styrene (Sigma Aldrich, 98%) were used as received unless stated otherwise. For the synthesis of OH-functionalized PP dry, oxygen-free PMH was employed as solvent for all polymerizations, methylaluminoxane (MAO, 30 wt. % solution in toluene) was purchased from Chemtura, diethyl zinc (DEZ, 1.0 M solution in hexanes), triisobutyl aluminum (TiBA, 1.0 M solution in hexanes) 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.

(3) Measurement Methods

(4) .sup.1H NMR analysis of the polystyrene homopolymers was carried out at 25 C. in deuterated chloroform (CDCl.sub.3) while the analysis of iPP and copolymers was performed at 80 C. in deuterated tetrachloroethene (TCE-d.sub.2). NMR spectra were recorded in 5 mm tubes using NMR Bruker Biospin AG spectrometer operating at frequencies of 300 MHz. Chemical shifts are reported in ppm versus tetramethylsilane and determined in reference to the signals of residual solvent.

(5) GPC.sup.1 (Gel Permeation Chromatography) of the polystyrene homopolymers was performed at 40 C. on a Waters GPC System equipped with three in series connected Waters Styrangel HR 5, 4, 1 columns with size 7.8300 mm, Waters 2414 RI detector and Waters 1515 Isocratic HPLC pump. THF was used as eluent at flow rate 1 mL/min.

(6) The molecular weights were calculated with respect to polystyrene standards (Sigma Sigma Aldrich). Waters 2707 autosampler was used for sample injections.

(7) GPC.sup.2 measurements of the polyolefins and polyolefin-based copolymers 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 weights were calculated with respect to polystyrene standards.

(8) Tensile tests were performed with a Zwick BZ100/SN5A tensile tester equipped with a 50 kN load cell. The tests were performed on injection molded samples having the dimension of 75 mm4 mm2 mm. A grip-to-grip separation of 35 mm was used. Constant cross-head speed was 50 mm/min.

(9) Izod impact strength was measured using a Zwick/Roell HIT5.5P tester according to ISO 180-2001. The dimensions of the injection molded sample bars without notch were 80 mm10 mm4 mm. For the samples the average value reported was derived for at least five specimens. The testing was carried out at room temperature.

(10) Glass transition (T.sub.g) and crystallization (T.sub.c) temperatures as well as enthalpies of the transitions 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.min.sup.1 from 50 C. to 240 C. The transitions were deduced from the second heating and cooling curves.

(11) SEM analysis The morphology of the blends was examined with a scanning electron microscope SEM of freeze fractured samples. The analysis were performed using scanning electron microscope Phenom with a magnification range: 80-100,000, digital zoom: 12(ProX/Pro). The samples were sputter coated using sputter coater with Au. For SEM analysis injection molded parts were used.

(12) Typical Procedure for the Synthesis of Hydroxyl End-Capped polypropylene (PP-OH):

(13) Polymerisation reactions were carried out in stainless steel Bchi reactors (300 mL). Prior to the polymerisation, the reactor was dried in vacuo at 40 C. and flushed with dinitrogen. PMH (90 mL) and MAO (30 wt. % solution in toluene) were added and stirred at 50 rpm for 20-30 min. TiBA (1.0 M solution in hexanes) and DEZ (1.0 M solution in hexanes) were added. The solution was saturated with propylene and stirred for 10 min. In a glove box, the catalyst was dissolved in toluene (c.a. 3 mL) and transferred into the reactor. The reactor was then pressurized to the desired pressure with propylene and the pressure was maintained constant for a predefined time. At the end of polymerisation, the propylene feed was stopped and after venting off the residual propylene, synthetic air was injected through a gas injection tube and the suspension was maintained under constant synthetic air pressure (6 bars) at 60 C. for 2 h with rigorous stirring (600 rpm) before quenching with 300 mL of acidified methanol (2.5 v% of concentrated HCl 37 wt %). The resulting white powder was then filtered, washed with methanol and dried at 60 C. under reduced pressure in a vacuum oven at 60 C. for 24 h. The thus obtained iPP-OH was analysed.

(14) Typical Procedure for the Synthesis of Br-Functionalized iPP

(15) In the synthesis of Br-functionalized iPP, iPP-OH and -bromoisobutyryl bromide were used. The reaction was carried out in dry 3-neck, round bottom flask under nitrogen atmosphere at 100 C. The molar ratio of iPP-OH/-bromoisobutyryl bromide/tri-ethylamine(Et.sub.3N)/4-dimethylaminopyridine(DMAP) was 1/10/10/0.005. The concentration of the solution was 10 wt. %.

(16) Procedure: magnetic stirrer, DMAP (catalyst) and iPP-OH were added to the flask. Then dry toluene (solvent) and dry triethylamine (bromide trap) was added through a septum. The flask was submerged in an oil bath and heated to 110 C. and at the end -bromoisobutyryl bromide was added dropwise. The reaction was carried out for 5 hours. The product was precipitated in methanol, filtered and dried under reduced pressure. The chemical structures of OH-functionalized iPP and Br-functionalized iPP were confirmed by .sup.1H NMR spectroscopy.

(17) Typical Procedure for the Synthesis of PP-block-PS Copolymers

(18) In the synthesis of PP-block-PS, OH-functionalized iPP and styrene, were used. The reaction was carried out in a Schlenk flask under nitrogen atmosphere at 110 C. An example of the molar ratio of styrene/iPP-Br/ligand/Cu(Br).sub.2 was 600/1/0.1/0.01. The concentration of the solution was 30 wt. %. As the reducing agent dry tin(II) 2-ethylhexanoate, Sn(EH).sub.2 or sodium hypophosphite monohydrate (NaH.sub.2PO.sub.2xH.sub.2O) was used.

(19) Procedure: a Schlenk flask was charged with reducing agent, iPP-Br, ligand (tris(2-pyridylmethyl)amine (TPMA)), styrene and anisole. Subsequently, four freeze-pump thaw cycles were applied to remove the oxygen. Then copper (II) bromide (Cu(Br).sub.2) was added to a frozen reaction mixture under nitrogen atmosphere. The flask was closed and vacuum was applied. Subsequently, nitrogen atmosphere was restored and the frozen mixture was inserted in oil bath at 110 C., and stirred for 24 hours. The synthesized polymer was purified by dissolution in toluene, precipitation in ethanol and dried under reduced pressure at 50 C. for 12 hours. The chemical structure of the synthesized copolymer was confirmed by .sup.1H NMR spectroscopy. The molecular weight and molecular weight distribution were determined by high temperature GPC.

(20) The block copolymers were characterized in terms of their molar and weight content of iPP in the product and PS block chain length. These values were determined based on .sup.1H NMR and GPC analysis.

(21) TABLE-US-00001 TABLE 1 Overview of the synthesized PP-block-PS copolymers. M.sub.n Br-iPP Reducing M/I/L/C/R/S T PS M.sub.n PS conv. Entry [kg/mol] agent % vol [ C.] wt. % [kg/mol] (%) PDI 1 2.5 Sn(EH).sub.2 79/1/0.1/0.01/0.1/30 110 66 5.7 78 2.2 2 7.7 Sn(EH).sub.2 100/1/0.1/0.01/0.1/80 110 40 5.2 90 2.7 3 7.7 Sn(EH).sub.2 120/1/0.1/0.01/0.1/65 110 57 10.0 88 3.1 4 7.7 Sn(EH).sub.2 650/1/0.1/0.01/0.1/ 110 73 20.8 27 2.6 5 7.7 Sn(EH).sub.2 1000/1/0.1/0.01/0.1/ 110 89 58.6 50 3.2 6 7.7 Sn(EH).sub.2 1500/1/0.4/0.04/0.4/ 110 91 78.1 70 7.4 7 7.7 SoHyp 800/1/0.1/0.01/1.6/ 110 83 38.4 50 3.5 8 7.7 SoHyp 1500/1/0.4/0.04/1.6/ 110 89 65.2 35 3.9 9 7.7 SoHyp 800/1/0.1/0.01/1.6/ 130 85 42.5 79 5.5 M-monomer, I-initiator, L-ligand, C-catalyst, R-reducing agent, S-solvent The reactions carried out for 24 h

(22) Typical Procedure for the Preparation of Polypropylene/PPO Compatibilised by PP-block-PS. A. Preparation of uncompatibilised PP/PPO blends: PPO and polypropylene were fed into the extruder chamber. The polymer blend was processed for 5 minutes at 290 C. under N.sub.2 atmosphere in the micro compounder. The micro compounder was equipped with co-rotating screws, a barrel with three 3 temperature zones and a nitrogen purge at 290 C. (three temperature zones set at 290 C.) with a screw rotation rate of 100 rpm. Afterwards the mixture was evacuated directly to a mini-injection moulding machine to prepare samples for morphology analysis (injection temperature: 290 C., mold temperature: 50 C.). B. Preparation of PP/PPO Blends Compatibilised by PP-block-PS Copolymer: poly(phenylene oxide) and PP-block-PS copolymer were fed into the extruder chamber. The mixture was processed for 3 minutes at 290 C. under N.sub.2 atmosphere in the micro compounder. The micro compounder was equipped with co-rotating screws, a barrel with three 3 temperature zones (all three temperature zones set at 290 C.) and a nitrogen purge at 290 C. with a screw rotation rate of 100 rpm. Afterwards, the mixture was evacuated, cooled and granulated. Subsequently, the product consisting of PPO and PP-block-PS copolymer, was mixed with polypropylene. The polymer blend was processed for 5 minutes at 290 C. Afterwards the mixture was evacuated directly to a mini-injection moulding machine to prepare samples for morphology analysis (injection temperature: 290 C., mold temperature: 50 C.).

(23) For each blend of the blends, indicated in Table 3, 10 gr samples were prepared with the indicated PP/PPO ratio and the indicated amount (0.5 g) of each compatibiliser (comp., C1, C2 or C3) was added on top to each sample to get 10.5 g of each compatibilised blend.

(24) For each blend of the blends, indicated in Table 4, 10 gr samples were prepared with the indicated PP/PPO ratio and the indicated amount (1 g) of compatibiliser (comp.) C2 was added on top to each sample to get 11 g of each compatibilised blend.

(25) For each blend of the blends, indicated in Table 5, 10 gr samples were prepared with the indicated PP/PPO ratio and the amount of compatibiliser (comp.) C2 indicated in each case (0.50 g, 0.75 g, 1.00 g or 1.25 g) was added on top to each sample to get each compatibilised blend.

(26) Analysis of samples of the blends listed in Table 3, compatibilised using PP-block-PS copolymers listed in Table 2 (C1, C2 and C3 corresponding to entries 2, 3 and 4 in Table 1) as well as of the blends listed in Tables 4 and 5, show improved compatibilisation compared to corresponding non-compatibilised blends, especially for example smaller and/or better dispersed domain of the dispersed phase and/or optionally an increased adhesion between the two different polymer phases.

(27) TABLE-US-00002 TABLE 2 Chemical composition of the PP-block-PS copolymers used for the preparation of PP/PPO blends. M.sub.n iPP PS M.sub.n PS Entry [kg/mol] wt. % [kg/mol] C1 7.7 40 5.2 C2 7.7 57 10.0 C3 7.7 73 20.8

(28) TABLE-US-00003 TABLE 3 Static mechanical properties of PP/PPO blends compatibilised by 5 wt. % PP-block-PS copolymers. PPO Impact strength Elongation at break Young Modulus content [kJ/m2] [%] [MPa] [wt. %] C1 C2 C3 B C1 C2 C3 B C1 C2 C3 B 20 25.01 30.29 22.14 14.83 5.90 8.74 7.10 5.50 1590 1669 1650 1340 50 20.63 14.22 13.57 11.85 3.80 3.60 3.10 3.30 1590 1800 1810 1500 80 14.21 11.93 11.90 9.88 2.80 2.29 2.53 2.70 1590 2100 2050 1750 C1, C2, C3-for the type of the compatibiliser see Table 2, B-uncompatibilised PP/PPO blend

(29) TABLE-US-00004 TABLE 4 Static mechanical properties of PP/PPO blends wit 10 wt. % of the compatibiliser PP.sub.7700-block-PS.sub.10000 (C2). PPO Impact strength Elongation at Young Modulus content [kJ/m.sup.2] break [%] [MPa] [wt. %] Blank compatibilised Blank compatibilised Blank compatibilised 0 9.59 400 1300 20 14.83 45.68 5.50 13.50 1340 1445 30 14.51 39.96 7.20 9.70 1450 1600 50 11.85 19.91 3.30 4.10 1500 1870 70 14.14 27.86 4.30 8.10 1530 1610 80 9.88 16.41 2.70 2.80 1750 2070 100 58.88 n. m. 20140 n.m.: below the measurable threshold

(30) TABLE-US-00005 TABLE 5 Static mechanical properties of 80/20 PP/PPO blends with diffrent content of compatibiliser PP.sub.7700-block-PS.sub.10000 (C2). Compatibiliser Impact strength Elongation at break Young Modulus content [wt. %] [kJ/m.sup.2] [%] [MPa] 5 30.29 8.74 1669 7.5 68.72 11.67 1590 10 45.68 13.50 1445 12.5 23.88 11.67 1550

(31) Tensile tests were performed to determine the maximum stress and elongation at break with a Zwick type Z020 tensile tester equipped with a 20 kN load cell. The tests were performed on injection molded samples having the dimensions of 75 mm4 mm2 mm. A grip-to-grip separation of 50 mm was used. The samples were pre-stressed to 3 N, then loaded with a constant cross-head speed 50 mm/min. The analysis was performed to determine the .sub.max and .sub.at break.

(32) Izod impact strength was measured using a Zwick/Roell HIT5.5P tester according to ISO 180-2001. The dimensions of the injection molded sample bars without notch were 60 mm10 mm4 mm. For each sample the average value reported was derived for at least five specimens. The testing was carried out at room temperature (25 C.).

(33) The morphology of the blends was examined with a scanning electron microscope SEM of freeze fractured samples of injection molded parts.

(34) Based on the analysis, one can see again that the compatibilisers according to the invention improve adhesion between the two different compatibilised phases. This leads to better material properties for the compatibilised blends.

(35) One can see from the Table 3 above that the Young Modulus may increase with an increasing Mn of the polystyrene part when going from 5.2 to 10kg/mol and may then stay similar or slightly decrease again for an Mn of the polystyrene part of 20.8 kg/mol.

(36) The examples thus show that the Young Modulus is especially improved when the Mn of the polystyrene part is between 4 and 16 kg/mol, especially between 5 and 15 kg/mol, particularly when the compatibilizer in an amount between 2 to 20 wt. %, especially 3 to 17 wt. %.

(37) TABLE-US-00006 TABLE 6 Materials used for the blends preparation M.sub.n M.sub.w MFR Density Materials [kg .Math. mol.sup.1] [kg .Math. mol.sup.1] PDI [g/10 min] [g/cm.sup.3] SABIC PP 525P 56.2 415.9 7.4 3.10 0.905 (230 C./2.16 kg) SABIC PP 520P 21.0 168.0 8.0 10.5 0.905 (230 C./2.16 kg) PPO Noryl 640 19.9 56.2 2.8 intristic viscosity = 0.476 0.4 dL/g (at 25 C. in chloroform)

(38) The above listed SABIC materials (Table 6) were used for the preparation of the blends listed in Table 3, 4, 5. The materials are commercially available from SABIC.