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 having a density of 920 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), 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 32 MPa, wherein said ethylene copolymer is produced with a Ziegler-Natta catalyst with an internal organic compound having the formula (I)
wherein in the formula (I) R 1 to R 5 are same or different and can be hydrogen, a linear or branched C 1 to C 8 -alkyl group, or a C 3 -C 8 -alkylene group, or two or more of R 1 to R 5 can form a ring, and the two oxygen-containing rings are individually saturated or partially unsaturated or unsaturated, wherein said multimodal ethylene copolymer composition has MFR 2 measured according to ISO 1133 at 190° C. of 0.5 to 2 g/10 min, wherein said ethylene copolymer is produced in at least two polymerization stages, 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 multimodal ethylene copolymer composition comprises an ethylene copolymer comprising at least one alpha-olefin comonomer of C 4 to C 10 .
3. The multimodal ethylene copolymer composition according to claim 2 , wherein said ethylene copolymer comprises at least two alpha-olefin-comonomer(s).
4. The multimodal ethylene copolymer composition according to claim 3 , wherein said ethylene copolymer comprises:
at least a first alpha-olefin comonomer comprising 1-hexene; and
a second alpha-olefin comonomer different from the first alpha-olefin comonomer.
5. The multimodal ethylene copolymer composition according to claim 4 , wherein said ethylene copolymer comprises at least 1-butene and 1-hexenecomonomers.
6. The multimodal ethylene copolymer composition according to claim 1 , wherein said multimodal ethylene copolymer composition has MFR 2 measured according to ISO 1133 at 190° C. of 0.7 to 1.5 g/10 min.
7. The multimodal ethylene copolymer composition according to claim 1 , wherein said multimodal ethylene copolymer composition has MFR 5 measured according to ISO 1133 at 190° C. of 0.3 to 12 g/10 min.
8. The multimodal ethylene copolymer composition according to claim 1 , wherein said multimodal ethylene copolymer composition has MFR 21 measured according to ISO 1133 at 190° C. of 20 to 180 g/10 min.
9. 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].
10. 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 .
11. The multimodal ethylene copolymer composition according to claim 1 , wherein said multimodal ethylene copolymer composition further comprises carbon black.
12. A cable jacket comprising the multimodal ethylene copolymer composition according to claim 1 .