Composition comprising heterophasic propylene copolymer

Abstract

The invention relates to composition comprising (A) a propylene-based polymer, (B1) a first elastomer of ethylene and α-olefin comonomer having 4 to 10 carbon atoms, (B2) a second elastomer of ethylene and α-olefin comonomer having 4 to 10 carbon atoms and (C) an inorganic filler, wherein (B1) the first elastomer has a density of 0.850 to 0.890 g/cm3 and a melt flow index of 5 to 50 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C., wherein (B2) the second elastomer has a density of 0.850 to 0.890 g/cm3 and a melt flow index of 0.55 to 4 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C., wherein the total amount of (B1) the first elastomer and (B2) the second elastomer is 2 to 30 wt % based on the total composition, wherein the amount of (C) the inorganic filler is 0.1 to 30 wt % based on the total composition.

Claims

1. A composition comprising: (A) a propylene-based polymer, (B1) a first elastomer that is ethylene-1-octene copolymer, (B2) a second elastomer that is ethylene-1-octene copolymer and (C) an inorganic filler, wherein (B1) the first elastomer has a density of 0.850 to 0.890 g/cm.sup.3 and a melt flow index of 5 to 50 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C., wherein (B2) the second elastomer has a density of 0.850 to 0.890 g/cm.sup.3 and a melt flow index of 0.55 to 4 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C., and wherein the total amount of (B1) the first elastomer and (B2) the second elastomer is 2 to 30 wt % based on the total composition, wherein the amount of (C) the inorganic filler is 0.1 to 30 wt % based on the total composition.

2. The composition according to claim 1, wherein the amount of the second elastomer with respect to the total of the first elastomer and the second elastomer in the composition is 10 to 90 wt %.

3. The composition according to claim 1, wherein the melt flow index of the first elastomer is 5 to 35 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C.

4. The composition according to claim 1, wherein the density of the first elastomer is 0.855 to 0.880 g/cm.sup.3.

5. The composition according to claim 1, wherein the density of the second elastomer is 0.850 to 0.870 g/cm.sup.3.

6. The composition according to claim 1, wherein the melt flow index of the second elastomer is 0.7 to 3 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C.

7. The composition according to claim 1, wherein the melt flow index of the first elastomer is 10 to 50 dg/min and measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C. and the melt flow index of the second elastomer is 0.55 to 3 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C.

8. The composition according to claim 1, wherein the composition is made by a process involving: adding the first elastomer and the second elastomer as separate components, adding the first elastomer and the second elastomer as one component made by melt-mixing the first elastomer and the second elastomer, or adding the first elastomer and the second elastomer as a bimodal elastomer made by polymerizing the first elastomer and subsequently polymerizing the second elastomer in the presence of the first elastomer or polymerizing the second elastomer and subsequently polymerizing the first elastomer in the presence of the second elastomer.

9. The composition according to claim 8, wherein the composition is made by a process involving adding the first elastomer and the second elastomer as a bimodal elastomer made by polymerizing the first elastomer and subsequently polymerizing the second elastomer in the presence of the first elastomer or polymerizing the second elastomer and subsequently polymerizing the first elastomer in the presence of the second elastomer.

10. The composition according to claim 1, wherein the propylene-based polymer is a heterophasic propylene copolymer consisting of (a) a propylene-based matrix, wherein the propylene-based matrix consists of a propylene homopolymer and/or a propylene copolymer consisting of at least 96 wt % of propylene monomer units and at most 4 wt % of ethylene monomer units and/or α-olefin monomer units having 4 to 10 carbon atoms, based on the total weight of the propylene-based matrix and wherein the propylene-based matrix is present in an amount of 65 to 95 wt % based on the total heterophasic propylene copolymer and (b) a dispersed ethylene-α-olefin copolymer, wherein the dispersed ethylene-α-olefin copolymer is an ethylene-propylene copolymer, wherein the ethylene-α olefin copolymer is present in an amount of 35 to 5 wt % based on the total heterophasic propylene copolymer.

11. The composition according to claim 10, wherein the propylene-based matrix is a propylene homopolymer, and/or the ethylene-α olefin copolymer is present in an amount of 30 to 5 wt %, based on the total heterophasic propylene copolymer, and/or the amount of ethylene monomer units in the ethylene-α-olefin copolymer is in the range of 40 to 65 wt %, based on the ethylene-α-olefin copolymer.

12. The composition according to claim 10, wherein the propylene-based matrix has a melt flow index of 0.3 to 300 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 230° C. and/or the dispersed ethylene-α-olefin copolymer has a melt flow index of 0.1 to 3 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 230° C.

13. The composition according to claim 1, wherein (A) the propylene-based polymer has a melt flow index of 30 to 150 dg/min measured according to ASTM D1238 2.16 kg/230° C. and/or the composition has a melt flow index of at least 20 dg/min measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 230° C.

14. The composition according to claim 1, wherein the inorganic filler is selected from the group consisting of calcium carbonate, talc, magnesium carbonate, synthetic carbonates, wollastonite, dolomite, gypsum, kaolinite, aluminum hydroxide, aluminosilicates, mica, natural siliconates, silica containing aggregates, zeolites and mixtures thereof.

15. A process for the preparation of the composition according to claim 1, comprising melt mixing (A), (B1), (B2) and (C).

16. An article comprising the composition of claim 1.

Description

EXPERIMENTS

(1) Propylene-Based Polymer

(2) Heterophasic propylene copolymer consisting of a matrix of a propylene homopolymer and a dispersed ethylene-propylene copolymer was used. The amount (RC) of the dispersed ethylene-propylene copolymer was 17.50 wt %. The amount (RCC2) of ethylene in the dispersed ethylene-propylene copolymer was 53.30 wt %.

(3) The MFI was as shown in Table 1, measured in accordance with ASTM D1238 using a 2.16 kg weight and at a temperature of 230° C.

(4) TABLE-US-00001 TABLE 1 Matrix Dispersed phase MFI ratio of matrix Total (dg/min) (dg/min) to dispersed (dg/min) 160.00 1.75 91.43 72.60

(5) Elastomer

(6) Elastomers of ethylene and 1-octene as shown in Table 2 were used. The MFI shown below was measured according to ASTM D1238 using a 2.16 kg weight and at a temperature of 190° C.

(7) TABLE-US-00002 TABLE 2 Elastomer MFI @ 190° C. Density (g/cm.sup.3) POE1 27.84 0.8678 POE2A 0.91 0.857 POE2B 1.02 0.8684

(8) Inorganic Filler

(9) Talc having a diameter d50 of 6 μm was used.

(10) Compositions as shown in Tables 3 and 4 were made by melt-mixing in a twin screw extruder. The total amount of the elastomers was 15 wt % and the amount of the talc was 15 wt %, both with respect to the total composition. In Table 3, the elastomers were POE1 and POE2A in amounts shown in the table. In Table 4, the elastomers were POE1 and POE2B in amounts shown in the table.

(11) The heterophasic propylene copolymer was pre-mixed with anti-oxidant additives and the elastomers, and then the pre-mixed pellets were dosed to 1.sup.st main hopper of the extruder. Talc was separately dosed to 2.sup.nd main hopper of the extruder. The temperature profile in the twin-extruder was 50-150-210-220-230-230-230-230-230-230-230° C., at a throughput of ˜25 kg/h at 300 rpm. The pellets were dried under 100° C. for 2 h and then injection molded to prepare the parts for testing by FANUC injection molding machine.

(12) The MFI of the composition was measured according to ASTM D1238 using a 2.16 kg weight at a temperature of 230° C.

(13) Izod impact strength was measured according to ASTM D 256 at temperatures shown in Tables 3 and 4.

(14) Flexural modulus was measured according to ASTM D 790.

(15) TABLE-US-00003 TABLE 3 15 wt % of (POE1 and POE2A) and 15 wt % of talc Experiments CEx1 Ex2 Ex3 Ex4 Ex5 Ex6 CEx7 POE2A/(POE1 + POE2A) (wt %) 0 30 40 50 60 70 100 MFI2.16 kg/230° C. 39.391 37.067 34.98 33.625 32.404 31.543 28.85 Flex modulus (MPa) 1000 1020 1030 1040 1040 1040 979 Notched Izod impact @ RT (J/m) 265 315 331 337 387 351 319 Notched Izod impact @ −20° C. (J/m) 45.8 59.8 61.5 59.1 65.5 62.6 59

(16) TABLE-US-00004 TABLE 4 15 wt % of (POE1 and POE2B) and 15 wt % of talc Experiments CEx1 Ex8 Ex9 Ex10 Ex11 Ex12 CEx13 POE2B/(POE1 + POE2B) (wt %) 0 30 40 50 60 70 100 MFI2.16 kg/230 °C. 39.391 36.356 34.719 34.303 33.298 32.971 28.129 Flex modulus (MPa) 1000 963 978 1000 998 1000 1020 Notched Izod impact @ RT (J/m) 265 301 312 285 294 266 183 Notched Izod impact @ −20° C. (J/m) 45.8 51 51.2 52.2 55.5 53.6 59

(17) The use of POE1 alone as the elastomer (CEx 1) leads to a high MFI of the final composition but also to a relatively low impact strength, especially at low temperatures.

(18) The use of POE2A alone as the elastomer (CEx 7) leads to a low MFI of the final composition although the impact strength is relatively high.

(19) The use of POE2B alone as the elastomer (CEx 13) leads to a low MFI of the final composition although the impact strength is relatively high at low temperatures.

(20) The use of POE1 in combination with POE2A or POE2B leads to a good combination of a high MFI of the final composition and a high MFI, compared to the use of a single elastomer. POE1 in combination with POE2A leads to a particularly high impact strength. In particular, a higher ratio of POE2A/(POE1+POE2A) (Ex 5 and 6) shows a significantly high impact strength.