초록 ▼

The invention relates to a syntactic polyolefin composition for pipe coating, wherein the composition comprises a β-nucleated propylene polymer and microspheres. The invention also relates to a method for the preparation of the composition for pipe coating and to an off-shore pipe coated with t

The invention relates to a syntactic polyolefin composition for pipe coating, wherein the composition comprises a β-nucleated propylene polymer and microspheres. The invention also relates to a method for the preparation of the composition for pipe coating and to an off-shore pipe coated with the syntactic polyolefin composition.

대표청구항 ▼

The invention claimed is: 1. A syntactic polyolefin composition for pipe coating, wherein the composition comprises: a β-nucleated propylene polymer comprising 0.0001-2.0 weight % of a β-nucleating agent, a polyolefin homopolymer having a melt flow rate of 100-1500 g/10 min at 230째 C./2.1

The invention claimed is: 1. A syntactic polyolefin composition for pipe coating, wherein the composition comprises: a β-nucleated propylene polymer comprising 0.0001-2.0 weight % of a β-nucleating agent, a polyolefin homopolymer having a melt flow rate of 100-1500 g/10 min at 230째 C./2.16 kg, and microspheres, said composition having a melt flow rate (MFR2; ISO 1133, condition D) at 230째 C./2.16 kg in the range of 0.05-30 g/10 min and an elongation at break of at least 3%. 2. A syntactic polyolefin composition according to claim 1, wherein said composition has a melt flow rate (MFR2; ISO 1133, condition D) at 230째 C./2.16 kg in the range of 0.5-10 g/10 min. 3. A syntactic polyolefin composition according to claim 1, wherein said composition has an elongation at break of >5%. 4. A syntactic polyolefin composition according to claim 1, wherein the β-nucleated propylene polymer is a (co)polymer which comprises at least 90.0 weight % of propylene and up to 10.0 weight % of α-olefins with 2 or 4 to 18 carbon atoms, and that the propylene polymer has a melt flow rate of 0.1-8 g/10 min at 230째 C./2.16 kg. 5. A syntactic polyolefin composition according to claim 1, wherein the amount of polyolefin is 0-20 weight %. 6. A syntactic polyolefin composition according to claim 1, wherein the tensile modulus of the composition is at least 1500 MPa determined according to ISO 527. 7. A syntactic polyolefin composition according to claim 1, wherein the compression strength at 20 MPa/80째 determined according to ASTM D695, is >10 MPa. 8. A syntactic polyolefin composition according to claim 1, wherein the K-value of the composition is less than 0.190 W/m째 K. 9. A syntactic polyolefin composition according claim 1, wherein the density of the composition is 500-850 kg/m3. 10. A syntactic polyolefin composition according to claim 1, wherein said microspheres are made of glass, ceramics, epoxy resin, phenolic resin or urea-formaldehyde resin. 11. A syntactic polyolefin composition according to claim 1, wherein said microspheres are untreated microspheres. 12. A syntactic polyolefin composition according to claim 1, wherein said microspheres have an outer diameter of 1-500 μm. 13. A syntactic polyolefin composition according to claim 1, wherein said microspheres are hollow. 14. A syntactic polyolefin composition according to claim 1, wherein said microspheres are present in an amount of 10-50 weight % of the composition. 15. A method for the preparation of a syntactic polyolefin composition for pipe coating according to claim 1, wherein the microspheres are evenly distributed by melt mixing in a composition comprising a β-nucleated propylene polymer and microspheres, said composition having a melt flow rate at 230째 C./2.16 kg in the range 0.05-30 g/10 min and in that the composition has an elongation at break of at least 3%. 16. A method according to claim 15, wherein said microspheres are added to the molten polymer. 17. A method according to claim 15, wherein the composition is compounded/homogenised and extruded as a coating on an off-shore pipe in one continuous step. 18. A method according to claim 15, wherein the composition is pelletized in a first step and in a subsequent step extruded as a coating on an off-shore pipe. 19. An off-shore pipe coated with a syntactic polyolefin composition, wherein the pipe is coated with a composition according to claim 1. 20. A syntactic polyolefin composition according to claim 1, wherein said composition has a melt flow rate (MFR2; ISO 1133, condition D) at 230째 C./2.16 kg in the range of 1.0-5 g/10 min. 21. A syntactic polyolefin composition according to claim 1, wherein said composition has an elongation at break of >10%. 22. A syntactic polyolefin composition according to claim 1, wherein the amount of polyolefin is 15-20 weight %. 23. A syntactic polyolefin composition according to claim 1, wherein the compression strength at 20 MPa/80째 determined according to ASTM D695, is >15 MPa. 24. A syntactic polyolefin composition according to claim 1, wherein said microspheres have an outer diameter of 5-200 μm. 25. A syntactic polyolefin composition according to claim 1, wherein said microspheres are present in an amount of 20-30 weight % of the composition.