Jacket with improved properties
The present invention relates to a multimodal ethylene copolymer composition having a density of 920 to 949 kg/m 3 and a flexural modulus, wherein said flexural modulus is following the equation: Flexural modulus [MPa]<21.35·density [kg/m3]−19585 [1]. The multimodal ethylene copolymer composition according to the invention can be used in a highly flexible cable jacket, preferably a power cable jacket.
1. A multimodal ethylene copolymer composition comprising an ethylene copolymer having a density of 930 to 949 kg/m 3 , measured according to ISO 1183-1:2004 Method A on compression, molded specimen prepared according to EN ISO 1872-2 (February 2007), obtainable by a process comprising
a first polymerization stage, wherein a first copolymer is produced from ethylene and an alpha-olefin comonomer, and
a second polymerization stage, wherein a second copolymer is produced from ethylene and an alpha-olefin comonomer,
said multimodal ethylene copolymer composition comprising at least two alpha-olefin comonomers selected from 1-butene and 1-hexene and a flexural modulus, wherein said flexural modulus is measured according to the method of ISO 178 by using compression molded test specimens produced according to EN ISO 1872-2, and wherein numerical values of said flexural modulus, in MPa, and density, in kg/m 3 follow the inequality:
Flexural modulus [MPa]<21.35·density [kg/m 3 ]19585 [1],
wherein the Flexural modulus is at least 245.5 MPa, and
wherein the Shore D (1s) of the multimodal ethylene copolymer composition, as measured according to ISO868 on specimen molded according to EN ISO 1872-2, is at least 53.
2. The multimodal ethylene copolymer composition according to claim 1 , wherein said ethylene copolymer is produced with a Ziegler-Natta catalyst.
3. The multimodal ethylene copolymer composition according to claim 1 , wherein said multimodal ethylene copolymer composition has MFR 2 of 0.1 to 4 g/10 min.
4. The multimodal ethylene copolymer composition according to claim wherein said multimodal ethylene copolymer composition has MFR 5 of 0.3 to 12 g/10 min.
5. The multimodal ethylene copolymer composition according to claim 1 , wherein said multimodal ethylene copolymer composition has MFR 21 of 20 to 180 g/10 min.
6. The multimodal ethylene, copolymer composition according to claim 1 , wherein the flexural modulus is following the inequality:
Flexural modulus [MPa]<21.35·density [kg/m 3 ]−19610 [2].
7. The multimodal ethylene copolymer composition according to claim 1 , wherein the density of said multimodal ethylene copolymer composition is 930 to 940 kg/m 3 .
8. The multimodal ethylene polymer composition according to claim 1 , wherein said multimodal ethylene copolymer composition further comprises carbon black.
9. A cable jacket comprising a multimodal ethylene copolymer composition comprising an ethylene copolymer having a density of 930 to 949 kg/m 3 , measured according to ISO 1183-1:2004 Method A on compression molded specimen prepared according to EN ISO 1872-2 (February 2007), obtainable by a process comprising
a first polymerization stage, wherein a first copolymer is produced from ethylene and an alpha-olefin comonomer, and
a second polymerization stage, wherein a second copolymer is produced from ethylene and an alpha-olefin comonomer,
said multimodal ethylene copolymer composition comprising at least two alpha-olefin comonomers selected from 1-butene and 1-hexene and a flexural modulus, measured according to the method of ISO 178 by using compression molded test specimens produced according to EN ISO 1872-2, and wherein numerical values of said flexural modulus, in MPa, and density, in kg/m 3 follow the inequality:
Flexural modulus [MPa]<21.35·density [kg/m 3 ]−19585 [1],
wherein the Flexural modulus is at least 245.5 MPa, and
wherein the Shore D (1s) of the multimodal ethylene copolymer composition, as measured according to ISO868 on specimen moulded according to EN ISO 1872-2, is at least 53.
10. The cable jacket according to claim 9 , wherein said multimodal ethylene copolymer is produced with a Ziegler-Natta catalyst.
11. The cable jacket according to claim 9 , wherein said multimodal ethylene copolymer composition has MFR 2 of 0.1 to 4 g/10 min.
12. The cable jacket according to claim 9 , wherein said multimodal ethylene copolymer composition has MFR 5 of 0.3 to 12 g/10 min.
13. The cable jacket according to claim 9 , wherein said multimodal ethylene copolymer composition has MFR 21 of 20 to 180 g/10 min.