Heat-shrinkable protective element
A heat-shrinkable protective element having at least one protective layer is obtained from a polymeric composition having a polymer material, where the polymeric composition additionally has an electrically conducting filler having a BET specific surface of at least 100 m 2 /g according to Standard ASTM D 6556.
1. Heat-shrinkable protective element comprising:
at least one protective layer obtained from a polymeric composition having a polymer material,
wherein the polymeric composition additionally has an electrically conducting filler having a BET specific surface of at least 100 m 2 /g according to Standard ASTM D 6556 (2014), and
wherein the protective layer is electrically insulating with an electrical conductivity of at most 1.10 −8 S/m, measured at 25° C. in direct current, and
wherein the protective layer becomes a semiconducting element with an electrical conductivity greater than 1.10 −8 S/m once shrunk.
2. Protective element according to claim 1 , wherein the electrically conducting filler has an aspect ratio of at least 10.
3. Protective element according to claim 1 , wherein the electrically conductive filler has an aspect ratio of at least 100.
4. Protective element according to claim 1 , wherein the electrically conducting filler is a carbon-based filler.
5. Protective element according to claim 1 , wherein the electrically conducting filler is selected from the group consisting of carbon blacks, carbon fibers, graphites, graphenes, fullerenes, carbon nanotubes and one of their mixtures.
6. Protective element according to claim 1 , wherein the polymeric composition has at most 30.0 parts by weight of electrically conducting filler and preferably at most 10.0 parts by weight of electrically conducting filler, per 100 parts by weight of polymer material.
7. Protective element according to claim 1 , wherein the polymer material has at least one olefin polymer.
8. Protective element according to claim 7 , wherein the olefin polymer is a copolymer of ethylene and vinyl acetate (EVA).
9. Protective element according to claim 1 , wherein said protective element is shrinkable and wherein the protective layer is noncrosslinked.
10. Shrunken protective element obtained from the protective element according to claim 1 , wherein the protective layer is semiconducting in the shrunken state with an electrical conductivity greater than 1.10 −3 S/m, measured at 25° C. in direct current.
11. Process for the manufacture of a protective element according to claim 1 , said protective element being heat-shrinkable, said process comprising the steps of:
i. hot drawing the polymeric composition; and
ii. cooling, in its drawn state, the polymeric composition drawn in stage i.
12. Cable comprising:
a shrunken protective element obtained from a protective element, that is heat shrinkable, defined according to claim 1 .
13. Cable according to claim 12 , wherein the protective layer is a semiconducting layer.
14. Process for the manufacture of a cable comprising:
a shrunken protective element according to claim 12 , said method comprising the steps of:
a. positioning the protective element that is heat shrinkable around a cable, and
b. heat treating the protective element positioned in stage a in order to form the shrunken protective element.