Pipe with high abrasion resistance

Abstract

A pipe- or tube-shaped article having an innermost layer, wherein the innermost layer has a thickness of 0.001 to 100 mm and comprises a polyolefin composition comprising a) a propylene-ethylene copolymer, wherein the amount of repeat units derived from ethylene is 1 to 20 wt % based on the weight of the propylene-ethylene copolymer and wherein the propylene-ethylene copolymer has a density of at most 0.9 g/cm3 as determined by ASTM D1505 and b) an olefin polymer selected from high-density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP) and combinations thereof.

Claims

1. A pipe- or tube-shaped article having an innermost layer, wherein the innermost layer has a thickness of 0.001 to 100 mm and comprises a polyolefin composition comprising a) a propylene-ethylene copolymer, wherein the amount of repeat units derived from ethylene is 1 to 20 wt % based on the weight of the propylene-ethylene copolymer and wherein the propylene-ethylene copolymer has a density of at most 0.9 g/cm.sup.3 as determined by ASTM D1505 and b) an olefin polymer selected from high-density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP) and combinations thereof.

2. The article according to claim 1, wherein the amount of the propylene-ethylene copolymer a) is in the range from ≥40 to ≤90 wt % based on the total amount of the propylene-ethylene copolymer a) and the olefin polymer b).

3. The article according to claim 1, wherein the tensile stress of the polyolefin composition is at least 10 MPa and/or the elongation at break is at least 430% as measured according to ASTM D638.

4. The article according to claim 1, wherein the abrasion weight loss of the polyolefin composition is at least less than 2%.

5. The article according to claim 1, wherein the Vicat temperature of the polyolefin composition is at least 40° C. as measured according to ASTM D1525 (10N/50 C/hrs).

6. The article according to claim 1, wherein the amount of repeat units derived from ethylene in the propylene-ethylene copolymer a) is at least 3 wt %, based on the weight of the copolymer.

7. The article according to claim 1, wherein the propylene-ethylene copolymer a) has a density in the range from ≥0.80 g/cm.sup.3 to ≤0.90 g/cm.sup.3, as determined by ASTM D1505 and/or wherein the propylene-ethylene copolymer a) has a MFI of at least ≥1.2 g/10 min and at most ≤21 g/10 min, as determined according to D1238 at 190° C. and a load of 2.16 kg.

8. The article according to claim 1, wherein the HDPE has a density of 0.940 to 0.970 g/cm.sup.3 measured according to ISO1183 and/or a melt flow rate of 0.03 to 40 g/10 min measured according to ISO1133 at 190° C. and a load of 21.6 kg and/or wherein the LLDPE has a density of 0.900 to 0.948 g/cm.sup.3 measured according to ASTM D1505 and/or a melt flow rate of 0.03 to 30 g/10 min measured according to ASTM D1238 at 190° C. and a load of 2.16 kg and/or wherein the PP has a melt flow rate of 0.01 to 200 g/10 min measured according to ASTM D1238 at 230° C. and a load of 2.16 kg).

9. The article according to claim 1, wherein the article has an outer diameter in the range of 2.5 to 255 cm and/or an inner diameter of 2 to 250 cm and/or wherein the article has one or more layers with a total layer thickness in the range of 0.3 to 100 mm.

10. The article according to claim 1, wherein the total weight of the propylene-ethylene copolymer a) and the olefin polymer b) is at least 90 wt % of the total composition.

11. The article according to claim 1, wherein the article comprises a layer comprising a polyolefin and wherein the layer is adjacent to the innermost layer.

12. The article according to claim 1, wherein the article comprises a layer comprising a high density polyethylene and wherein the layer is adjacent to the innermost layer.

13. A method of making the article according to claim 1, the method comprising extruding the polyolefin composition.

14. A method comprising transporting abrasive solids or slurry solutions by passing the solids or the slurry solutions through the article according to claim 1.

15. The article according to claim 1, wherein the amount of the propylene-ethylene copolymer a) is in the range from ≥50 to ≤90 wt % based on the total amount of the propylene-ethylene copolymer a) and the olefin polymer b).

Description

EXAMPLES

1. Test Methods

(1) a) Density

(2) The density is measured according to the standards mentioned in table 1.

(3) b) Melt Flow Rate (MFR)

(4) The MFR is measured according the standards mentioned in table 1.

(5) c1) Abrasion Resistance for Part 1

(6) Abrasion resistance is measured according to ISO15527:2007. For testing round samples with a hole inside and with the dimensions of 4 mm thickness*30 mm outer diameter*8 mm inner diameter are prepared. The tests are performed on a Zhangjiakou Xuanhuakehua testing machine co. ltd., MSH type. The sample plate is rotated at 673 r/min for 7 h. After the test, the samples are cleaned by water and ultrasonic for 30 min, then the sample are dried at 50° C. for 4 h. The weight of the samples before and after testing are recorded.

(7) The weight loss percentage provided is calculated by the formula
Abrasion weight loss=((Sample weight before test−Sample weight after test)/Sample weight before test)*100%.
c2) Abrasion Resistance for Part 2

(8) Abrasion resistance is measured according to ISO15527:2010. For testing rectangle samples with the dimensions of 76.2*25.4*6.35 mm with two small holes (diameter 10.5 & 4 mm) inside. The tested are performed on a JJFLT equipment produced by JJ TEST. The sample plate is rotated at 1200 r/min for 7 h with the slurry temperature less than 23° C. After the test, the samples are cleaned by water and ultrasonic for 30 min, then the sample are dried at 50° C. for 4 h. The weight of the samples before and after testing are recorded.

(9) The weight loss percentage provided is calculated by the formula
Abrasion weight loss=((Sample weight before test−Sample weight after test)/Sample weight before test)*100%.
d) Tensile Test

(10) Tensile test is measured according to ASTM D638-14 (Standard Test Method for Tensile Properties of Plastics) with a test speed 50 mm/min. Testing bar TYPE I with the dimension: 57.00*13.00*3.18*166 mm is used. For each sample, five bars are tested, the average value is reported.

(11) e) Vicat Temperature

(12) The Vicat temperature is measured according to ASTM D1525, 10N/50 C/hrs.

2. Materials (Part 1 and Part 2)

(13) Table 1 gives an overview of the used materials.

(14) TABLE-US-00001 TABLE 1 Overview of used materials and their MFR and density. Material Density, g/cm3 MFR, g/10 min Comonomer Ethylene-octene 0.863 0.5 C8, 39 wt % copolymer (ASTM D1505-10) (ASTM D1238 SABIC C0560D at 190° C. and 2.16 kg) Propylene-ethylene 0.862 1.4 C2, 16 wt % copolymer (ASTM D1505-10) (ASTM D1238 Vistamaxx 6102 at 190° C. and 2.16 kg) HDPE 0.954 2.7 SABIC B5403 (ISO 1183) (ISO1133 at 190° C. and 21.6 kg) LLDPE 0.918 1.0 SABIC 118N (ASTM D1505-10) (ASTM D1238 at 190° C. and 21.6 kg) PP 0.897 0.25 SABIC 651H (ASTM D1505-10) (ASTM D1238 at 230° C. and 2.16 kg)

3. Experiments and Results

(15) Part 1

(16) The components were pre-blended and then melt-mixed and extruded using a twin extruder from Coperion, type ZSK26Mc, according to the settings of Table 2.

(17) TABLE-US-00002 TABLE 2 Overview Extruder settings. Product POE/HDPE Zone 1 (° C.) 20 Zone 2 (° C.) 60 Zone 3 (° C.) 120 Zone 4 (° C.) 200 Zone 5 (° C.) 200 Zone 6 (° C.) 200 Zone 7 (° C.) 200 Zone 8 (° C.) 230 Zone 9 (° C.) 230 Zone 10 (° C.) 230 Die Temp (° C. ) 230 Screw speed (RPM) 200 Output (kg/hr) 20

(18) Table 3 gives an overview of HDPE compositions and their properties. The wt % HDPE are based the amount of HDPE and the polyolefin elastomer (POE) in the composition. Different compositions of HDPE and propylene-ethylene copolymers (inventive samples) were prepared and compared to compositions of HDPE and ethylene-octene copolymers (comparative examples) with the same wt % of HDPE.

(19) TABLE-US-00003 TABLE 3 Overview of Polyolefin elastomer POE and HDPE blends and their properties. Polyolefin elastomer (POE)/HDPE blends 10 wt % 20 wt % 30 wt % 40 wt % HDPE HDPE HDPE HDPE Inventive Examples Propylene- Abrasion weight 0.71 0.25 0.09 0.10 ethylene loss (%) copolymer Tensile stress 10 12 14 15 (MPa) Tensile 655 755 764 723 Elongation (%) Vicat 44 48 48 52 temperature (° C.) Comparative Examples Ethylene- Abrasion weight 0.74 0.66 0.39 octene loss (%) copolymer Tensile stress 7 (MPa) Tensile 176 Elongation (%)

(20) The abrasion weight loss of the propylene-ethylene copolymer based compositions is less in comparison to the comparative examples, which are based on the same wt % of HDPE, but which comprise an ethylene-octene copolymer. The weight loss is less for the propylene-ethylene copolymer based compositions, although the MFR of the ethylene-octene copolymer is lower, consequently the ethylene-octene copolymer has a higher molecular weight, which should lead to a better abrasion resistance as known for example from UHMWPE. Furthermore, the tensile stress and the elongation at break are much better for the inventive examples.

(21) Part 2

(22) The components were pre-blended and then melt-mixed and extruded using a twin extruder from Coperion, type ZSK26Mc, according to the settings of Table 4.

(23) TABLE-US-00004 TABLE 4 Overview Extruder settings. Product POE/HDPE POE/LLDPE POE/PP Zone 1 (° C.) 100 80 80 Zone 2 (° C.) 180 180 210 Zone 3 (° C.) 180 180 210 Zone 4 (° C.) 180 180 210 Zone 5 (° C.) 180 180 210 Zone 6 (° C.) 180 180 210 Zone 7 (° C.) 180 180 210 Zone 8 (° C.) 180 180 210 Zone 9 (° C.) 180 180 210 Zone 10 (° C.) 180 180 210 Die Temp (° C.) 180 180 210 Screw speed (RPM) 300 300 300

(24) TABLE-US-00005 TABLE 5 Overview of POE and HDPE, POE and LLDPE, POE and PP blends and their properties. Polyolefin elastomer (POE)/HDPE blends 10 wt % 20 wt % 10 wt % 20 wt % 10 wt % 20 wt % HDPE HDPE LLDPE LLDPE PP PP Inventive Examples Propylene- Abrasion 0.09 0.26 0.02 0.03 0.03 0.06 ethylene weight loss copolymer (%) Tensile — — 7.4 8.6 5.7 10.8 stress (MPa) Tensile — — 603 603 574 572 Elongation (%) Vicat 38 40 38 39 51 62 temperature (° C.) Comparative Examples Ethylene- Abrasion 0.09 0.16 0.11 0.09 0.11 0.1 octene weight loss copolymer (%) Tensile — — 7.2 8.9 6.0 6.1 stress (MPa) Tensile — — 456 476 362 214 Elongation (%) Vicat 39 46 39 42 48 56 temperature (° C.)

(25) TABLE-US-00006 TABLE 6 Comparative examples - Overview of abrasion weight loss of HDPE, LLDPE and PP. Abrasion weight Material loss (%) 100% HPDE 2.71 100% LLDPE 1.50 100% PP 5.17

(26) The abrasion weight loss of the propylene-ethylene copolymer based compositions with HDPE, LLDPE and PP is much less in comparison to HDPE, LLDPE and PP as shown in table 5 and 6.