Polypropylene composition and preparation method thereof, and film or sheet prepared from the polypropylene composition and use thereof

Abstract

A polypropylene composition, a preparation method thereof, and a film or a sheet prepared from the polypropylene composition and use thereof. The composition includes 45 parts to 75 parts of a polypropylene, 10 parts to 35 parts of an elastomer, 5 parts to 20 parts of a polyethylene, 0.1 parts to 0.5 parts of an antioxidant, and 0.1 parts to 0.5 parts of a lubricant. A half peak width of a crystallization peak of the polypropylene is 5 C. to 10 C., and a peak temperature of the crystallization peak of the polypropylene is 105 C. to 115 C. The polypropylene composition has a good tenacity, especially a30 C. low-temperature impact performance. The film or the sheet prepared from the composition and applied to automotive interior parts, can enable the external accessories not only to be less likely to generate sharp fragments while being strongly impacted, but also to have a matte characteristic.

Claims

1. A polypropylene composition, characterized in that, it comprises following components in parts by weight based on the whole composition: a polypropylene 45 to 75 parts; an elastomer 10 to 35 parts; and a polyethylene 5 to 20 parts; wherein a half peak width of a crystallization peak of the polypropylene is 5 C. to 10 C.; a peak temperature of the crystallization peak of the polypropylene is 105 C. to 115 C.; and the half peak width of the crystallization peak and the peak temperature of the crystallization peak are tested at a cooling rate of 10 C./min according to a standard of ISO 11357.

2. The polypropylene composition according to claim 1, wherein the polypropylene is a homopolymerized polypropylene, with an isotactic index of 94% to 98% and a melt flow rate of 1 g/10 min to 5 g/10 min under a load of 2.16 kg at 230 C.

3. The polypropylene composition according to claim 1, wherein the elastomer is one or a mixture of an ethene-hexene copolymer, an ethene-butene copolymer and an ethane-octene copolymer, a density of the elastomer is 0.850 g/cm.sup.3 to 0.865 g/cm.sup.3, and the melt flow rate at 190 C. under the load of 2.16 kg is 0.1 g/10 min to 3 g/10 min.

4. The polypropylene composition according to claim 1, wherein the polyethylene is a high-density polyethylene HDPE, with a density of 0.94 g/cm.sup.3 to 0.97 g/cm.sup.3, and the melt flow rate at 190 C. under the load of 2.16 kg is 0.01 g/10 min to 0.5 g/10 min.

5. The polypropylene composition according to claim 1, wherein the polypropylene composition further comprises 0.1 part to 0.5 part of an antioxidant and 0.1 part to 0.5 part of a lubricant in parts by weight based on the whole composition.

6. The polypropylene composition according to claim 5, wherein the antioxidant is a mixture of a hindered phenol antioxidant and a phosphites antioxidant in a ratio of 1:1-2.

7. The polypropylene composition according to claim 5, wherein the lubricant is one or a mixture of a polyethylene wax and an oxidized polyethylene wax.

8. A preparation method of the polypropylene composition as in one of claims 1-7, characterized in that, it comprises the following steps: (1) weighing each component in proportion, blending a polypropylene, an elastomer and a polyethylene in a high-speed mixer for 1 to 3 minutes, then adding an antioxidant and a lubricant followed by blending again for 1 to 3 minutes, with a rotate speed of 1000 to 2000 rpm, and obtaining a premix compound; and (2) melt-extruding the premix compound by a twin-screw extruder, a temperature of each district of the screw being 190-230 C., and obtaining the polypropylene composition by a vacuum pelletizing.

9. The method according to claim 8, further comprises: preparing a film or a sheet from the polypropylene composition; and using the film or the sheet in forming at least one product of automotive interior parts.

10. The method according to claim 9, wherein the at least one product of automotive interior parts are an instrument board, an auxiliary instrument board, an upright or a door panel.

11. The method according to claim 9, wherein the film or the sheet has a thickness of 0.01 mm to 10 mm.

12. The method according to claim 11, wherein the at least one product of automotive interior parts are an instrument board, an auxiliary instrument board, an upright or a door panel.

13. A film or a sheet prepared from the polypropylene composition as in one of claims 1-7.

14. The film or the sheet according to claim 13, wherein a thickness of the film or the sheet is 0.01 mm to 10 mm.

15. The polypropylene composition according to claim 1, wherein the half peak width of the crystallization peak of the polypropylene is 7 C. to 9 C.

16. The polypropylene composition according to claim 1, wherein the peak temperature of the crystallization peak of the polypropylene is 108 C. to 112 C.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(1) The present invention is specifically described below by embodiments, but the present invention is not limited by the following embodiments.

(2) The raw materials used in the embodiments and comparative examples are described as below, but not limited by these:

(3) Polypropylene 1: an isotactic index is 94%, a MFR (230 C., 2.16 kg) is 1.0 g/10 min, a half peak width of a crystallization peak of the polypropylene is 5 C. and a peak temperature of the crystallization peak of the polypropylene is 110 C.;

(4) Polypropylene 2: the isotactic index is 95%, the MFR (230 C., 2.16 kg) is 3.0 g/10 min, the half peak width of the crystallization peak of the polypropylene is 7.3 C. and the peak temperature of the crystallization peak of the polypropylene is 105 C.;

(5) Polypropylene 3: the isotactic index is 98%, the MFR (230 C., 2.16 kg) is 5.0 g/10 min, the half peak width of the crystallization peak of the polypropylene is 10 C. and the peak temperature of the crystallization peak of the polypropylene is 108 C.;

(6) Polypropylene 4: the isotactic index is 96%, the MFR (230 C., 2.16 kg) is 4.0 g/10 min, the half peak width of the crystallization peak of the polypropylene is 9 C. and the peak temperature of the crystallization peak of the polypropylene is 112 C.;

(7) Polypropylene 5: the isotactic index is 96%, the MFR (230 C., 2.16 kg) is 2.0 g/10 min, the half peak width of the crystallization peak of the polypropylene is 5 C. and the peak temperature of the crystallization peak of the polypropylene is 115 C.;

(8) Polypropylene 6: the isotactic index is 98%, the MFR (230 C., 2.16 kg) is 8.0 g/10 min, the half peak width of the crystallization peak of the polypropylene is 12 C. and the peak temperature of the crystallization peak of the polypropylene is 125 C.;

(9) Polypropylene 7: the isotactic index is 98%, the MFR (230 C., 2.16 kg) is 0.5 g/10 min, the half peak width of the crystallization peak of the polypropylene is 4.8 C. and the peak temperature of the crystallization peak of the polypropylene is 102 C.;

(10) Ethene-hexene copolymer: a density is 0.860 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 0.5 g/10 min;

(11) Ethene-butene copolymer: the density is 0.865 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 0.5 g/10 min;

(12) Ethane-octene copolymer: the density is 0.855 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 1.0 g/10 min;

(13) Ethene-propylene copolymer: the density is 0.856 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 1.0 g/10 min;

(14) High-density polyethylene 1: the density is 0.94 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 0.01 g/10 min;

(15) High-density polyethylene 2: the density is 0.95 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 0.05 g/10 min;

(16) High-density polyethylene 3: the density is 0.97 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 0.5 g/10 min;

(17) High-density polyethylene 4: the density is 0.95 g/cm.sup.3, and the MFR (190 C., 2.16 kg) is 8.0 g/10 min; and

(18) Antioxidant: the antioxidant is a mixture of a hindered phenol antioxidant 1010 and a phosphites antioxidant 168 in a ratio of 1:1.

Embodiments 1-8

(19) Components were weighed according to the parts by weight as shown in Table 1. The polypropylene, an elastomer and the high-density polyethylene were first blended for 3 minutes in a high-speed mixer, and then the antioxidant and a lubricant were added followed by blending again for 2 minutes, with a rotate speed of 2000 rpm, and a premix compound was obtained; the premix compound was melt-extruded by a twin-screw extruder, a temperature of each district of the screw was maintained at 190 to 230 C., and a polypropylene composition that has a good low-temperature tenacity was obtained by a vacuum pelletizing. The polypropylene composition was made into corresponding test pieces with which mechanical performances of the polypropylene composition were tested, and the specific values were listed in Table 1.

(20) TABLE-US-00001 TABLE 1 Components and performances of the polypropylene composition in the embodiments Number Embodiments (in parts by weight) Raw Material 1 2 3 4 5 6 7 8 polypropylene 1 74.6 polypropylene 2 56.3 64.3 69.3 polypropylene 3 45.2 54.1 polypropylene 4 52.2 polypropylene 5 54.3 ethene-hexene 20 10 10 copolymer ethene-butene 35 15 28 15 copolymer ethane-octene 25 20 20 copolymer high-density 5 19 polyethylene 1 high-density 18 10 20 20 polyethylene 2 high-density 19 15 polyethylene 3 antioxidant 0.2 0.3 0.4 0.5 0.4 0.4 0.4 0.5 polyethylene wax 0.2 0.4 0.4 0.2 0.2 0.4 0.2 oxidized 0.3 0.3 polyethylene wax Mechanical performances and gloss density (g/cm.sup.3) 0.903 0.906 0.910 0.907 0.905 0.911 0.908 0.904 melting index 0.83 2.68 3.21 2.86 2.80 3.10 2.15 1.22 (g/10 min) tensile strength 18.6 18.4 17.9 18.9 18.8 18.8 18.9 18.7 (MPa) elongation at 320 347 415 368 440 380 480 311 break (%) bending strength 17.2 15.5 14.5 15.9 15.3 15.0 16.1 16.8 (MPa) bending modulus 730 567 496 611 593 550 680 710 (MPa) notched Izod 56.8 68.5 75.3 64.3 65.5 63.4 68.2 53.2 impact strength (23 C.) (kJ/m.sup.2) notched Izod 48.3 61.5 66.9 60.8 48.7 58.4 67.3 44.2 impact strength (30 C.) (kJ/m.sup.2) gloss (60) 42.1 36.7 32.4 38.6 36.1 37.2 31.2 45.0

Comparative Examples 1-6

(21) Components were weighed according to the parts by weight as shown in Table 2, a preparation method is the same as that of the embodiments, and performance test values were listed in Table 2.

(22) TABLE-US-00002 TABLE 2 Components and performances of the polypropylene composition of the comparative examples Number Comparative Examples (in parts by weight) Raw Material 1 2 3 4 5 6 polypropylene 1 74.6 polypropylene 2 56.3 polypropylene 3 50 54.1 polypropylene 6 45.2 polypropylene 7 64.3 ethene-hexene 20 10 copolymer ethene-butene 35 15 copolymer ethane-octene 20 copolymer ethene-propylene 30 copolymer high-density 20 polyethylene 1 high-density 18 polyethylene 2 high-density 19 15 polyethylene 3 high-density 20 polyethylene 4 antioxidant 0.2 0.3 0.4 0.5 0.5 0.4 polyethylene wax 0.4 0.4 0.2 0.2 oxidized 0.2 0.3 polyethylene wax Mechanical performances and gloss density (g/cm.sup.3) 0.900 0.902 0.912 0.905 0.912 0.920 melting index 0.91 1.82 5.15 0.40 3.08 4.62 (g/10 min) tensile strength 16.7 28.3 19.1 23.6 16.2 16.5 (MPa) elongation at 480 78 156 276 352 233 break (%) bending strength 15.1 31.0 16.3 18.6 14.1 15.3 (MPa) bending modulus 580 1100 986 685 480 620 (MPa) notched Izod 64.3 18.6 32.3 58.3 61.1 56.2 impact strength (23 C.) (kJ/m.sup.2) notched Izod 30.7 4.2 4.1 3.8 4.2 3.5 impact strength (30 C.) (kJ/m.sup.2) gloss (60) 68.2 62.3 59.8 46.2 65.0 72.6

(23) Each performance test was performed according to the standard in the Table 3 below:

(24) TABLE-US-00003 TABLE 3 Test Item Unit Test Standard melt flow rate g/10 min ISO 1133 density g/cm.sup.3 ISO 1183 tensile strength MPa ISO 527-1, 527-2 elongation at break % ISO 527-1, 527-2 bending strength MPa ISO 178 bending modulus MPa ISO 178 notched Izod impact strength (23 C.) kJ/m.sup.2 ISO 180 notched Izod impact strength kJ/m.sup.2 ISO 180 (30 C.) gloss (60) ASTM D523 half peak width of the crystallization C. ISO 11357 peak temperature of the C. ISO 11357 crystallization peak

(25) It can be seen from the test results of the mechanical performances and the gloss of the embodiments and comparative examples that by using the polypropylenes with specific half peak width of the crystallization peak and peak temperature of the crystallization peak as a domain resin and synergistically toughening by a combination of the polyethylenes and the elastomers, the obtained polypropylene composition material achieved a greater improvement in impact performances, especially 30 C. low-temperature impact performance. In addition to a good impact tenacity, the prepared material has a relatively low gloss. A film or a sheet made from the material could be applied to automotive interior parts, efficiently solving the issue of that the automotive interior parts tend to undergo a brittle fracture under a low-temperature high-speed impact.