Electric cable coated with polyolefin and polymer with ester and epoxy groups

• US 6,436,536 B2
• Filed: 02/22/2001
• Issued: 08/20/2002
• Est. Priority Date: 06/21/1995
• Status: Expired due to Term

• Current Assignee: Prysmian Cavi E Sistemi Italia Srl (Prysmian SPA)
• Original Assignee: Pirelli Cavi S.p.A.
• Inventors: Peruzzotti, Franco, Garcia, Valeria
• Primary Examiner(s): Sellers, Robert E. L.
• Application Number:
  US09/791,225
• Publication Number:
  US 20020001714A1
• Time in Patent Office: 544 Days
• Field of Search: 174/105.SC, 174/110.PM, 174/121.SR, 525/208, 428/375
• US Class Current: 428/375
• CPC Class Codes: C08K 5/14 Peroxides
• CPC Class Codes: C08L 2203/202 use in electrical wires or wirecoating
• CPC Class Codes: C08L 23/02 not modified by chemical after-treatment
• CPC Class Codes: C08L 23/06 Polyethene
• CPC Class Codes: C08L 23/0884 Epoxide containing esters
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/06 Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof
• CPC Class Codes: C08L 2666/22 Macromolecular compounds not provided for in C08L2666/16 - C08L2666/20
• CPC Class Codes: H01B 3/441 from alkenes
• CPC Class Codes: H01B 7/2813 Protection against damage caused by electrical, chemical or water tree deterioration
• CPC Class Codes: H01B 7/282 Preventing penetration of fluid , e.g. water or humidity, into conductor or cable
• CPC Class Codes: H01B 7/2825 using a water impermeable sheath
• CPC Class Codes: Y10T 428/2933 Coated or with bond, impregnation or core

Abstract

A polymeric composition for coating electric cables for power transmission at medium/high voltage, having an improved resistance against the formation of the so-called water trees, comprises a polymeric polyolefin base including, in parts by weight to the total weight thereof, from 0.5 to 15 parts of ester groups and from 0.01 to 5 parts of epoxy groups. Electric cables according to the invention comprise at least one electrically conducting core (2) and an insulation coating (5) comprising the aforementioned polymeric composition.

Claims

1. An electric cable comprising at least one conducting core and at least one electrically insulating coating obtained by extruding onto said conducting core a polymeric composition comprising an effective amount of a peroxide cross-linking agent and subsequently cross-linking the composition vie peroxide, said composition further comprising a polyolefin polymeric base consisting essentially of an ethylene polymer and, in parts by weight relative to the total weight thereof amounts:

from 0.5 to 15 parts of ester groups; and

from 0.01 to 5 parts of epoxy groups, said amounts of ester and epoxy groups, in combination, being such as to reduce the formation of water trees within the insulation coating after electric ageing in water, wherein said ester and epoxy groups are provided by an ethylene/acrylic ester/glycidyl methacrylate terpolymer having a Melt Index of from 0.1 g/10′

to 40 g/10′

.

2. An electric cable comprising at least one conducting core and at least one

insulation coating obtained by extruding onto said conducting core a polymeric composition including a polyolefin polymeric base and a polymeric compound having a Melt Index of from 0.1 g/10′

to 40 g/10′

, wherein the polymeric composition includes, in parts by weight to the total weight thereof,

from 0.5 to 15 parts of ester groups and

from 0.1 to 5 parts of epoxy groups, said amounts of ester and epoxy groups, in combination, being such as to reduce the formation of water trees within the insulation coating after electric ageing in water.