Polyethylene with a high vinyl content and with a low MFR
The invention relates to a polyethylene having a melt flow rate at (2.16) kg loading (MFR 2 ), determined according to method ISO1133-1:2011, which MFR 2 is A g/10 min and A 1 ≤A≤A 2 ; wherein A 1 is (0.5) and A 2 is (1.70), and containing a total amount of vinyl groups which is B vinyl groups per (1000) carbon atoms, and B 1 ≤B, wherein B 1 is (0.45), determined according to method ASTM D6248-98, a polymer composition, an article being e.g. a cable, e.g. a power cable, and processes for producing a polyethylene, a polymer composition and an article, and an article; useful in different end applications, such as wire and cable (W&C) applications.
1. A polyethylene, characterized in that:
the polyethylene has a melt flow rate at 2.16 kg loading (MFR 2 ), determined according to method ISO 1133-1:2011, wherein the MFR 2 is A g/10 min and 0.5≤A≤1.70; and
the polyethylene contains a total amount of vinyl groups, determined according to method ASTM D6248-98, which is B vinyl groups per 1000 carbon atoms and 0.45≤B.
2. The polyethylene according to claim 1 , wherein 0.58≤B.
3. The polyethylene according to claim 1 , wherein 0.5≤A≤1.65, 1.60, 1.55 or 1.50.
4. The polyethylene according to claim 1 , wherein B≤3.0.
5. The polyethylene according to claim 1 , wherein the polyethylene is an unsaturated LDPE polymer.
6. The polyethylene according to claim 1 , wherein the polyethylene is a homopolymer of ethylene or is an unsaturated copolymer comprising one or more polyunsaturated comonomer(s).
7. The polyethylene according to claim 1 , wherein the polyethylene is a copolymer of:
a monomer;
at least one polyunsaturated comonomer; and
zero or one or more other comonomer(s);
wherein said total amount of vinyl groups (B) present in the polyethylene includes vinyl groups originating from said at least one polyunsaturated comonomer.
8. The polyethylene according to claim 1 , wherein the polyethylene is a copolymer of:
a monomer; and
at least one polyunsaturated comonomer;
wherein the polyunsaturated comonomer is a straight carbon chain with at least 8 carbon atoms, at least two non-conjugated double bonds of which at least one is terminal, and at least 4 carbon atoms between the non-conjugated double bonds.
9. The polyethylene according to claim 1 , wherein the polyethylene is a copolymer of ethylene and 1,7-octadiene.
10. The polyethylene according to claim 1 , wherein the polyethylene is an unsaturated low density polyethylene (LDPE) homopolymer or copolymer.
11. The polyethylene according to claim 1 , wherein 0.88≤B.
12. The polyethylene according to claim 1 , wherein B≥0.95, 1.00, 1.05 or 1.10.
13. The polyethylene according to claim 1 , wherein the polyethylene has a complex viscosity (η*) at 0.05 rad/sec, which is X Pas, and 10000≤X≤30000, wherein the complex viscosity (η*) is determined according to method ISO 6721-1 on stabilized samples of the polyethylene.
14. The polyethylene according to claim 1 , wherein the polyethylene has:
a complex viscosity (η*) at 0.05 rad/sec, which is X Pas, and 12000≤X≤28000, and
a complex viscosity (η*) at 300 rad/sec, which is Y Pas, and 250≤Y≤330,
wherein the complex viscosities (η*) are determined according to method ISO 6721-1 on stabilized samples of the polyethylene.
15. The polyethylene according to claim 1 , wherein the polyethylene has:
a complex viscosity (η*) at 0.05 rad/sec, which is X Pas, and 15500≤X≤24000, and
a complex viscosity (η*) at 300 rad/sec, which is Y Pas, and 250≤Y≤330,
wherein the complex viscosities (η*) are determined according to method ISO 6721-1 on stabilized samples of the polyethylene.
16. A polymer composition, which is crosslinkable or crosslinked, wherein the polymer composition comprises, or is obtained from, the polyethylene according to claim 1 .
17. An article comprising the polyethylene according to claim 1 wherein the article is a cable or a cable layer.
18. The article according to claim 17 , wherein the article is a power cable or a power cable layer.
19. The article according to claim 17 , wherein the article comprises an insulating layer.
20. A process for producing the polyethylene according to claim 1 , wherein the process is a continuous and high pressure process.
21. A process for producing the article according to claim 17 , wherein the process comprises using the polyethylene to produce the article.
22. The process according to claim 21 , wherein said article is a power cable and wherein said process comprises the steps of:
a 0 ) meltmixing the polyethylene, optionally together with further components; and
a) applying the meltmix obtained from step a 0 ) on a conductor to form at least one cable layer.
23. The process according to claim 22 , wherein said article is a crosslinked power cable and wherein said process further comprises the step of:
b) crosslinking the at least one cable layer obtained from step a).
24. The polyethylene according to claim 8 , wherein the polyunsaturated comonomer is selected from the group consisting of 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene, and mixtures thereof.