Water-tight electric cable

• US 4,308,416 A
• Filed: 12/17/1980
• Issued: 12/29/1981
• Est. Priority Date: 07/11/1979
• Status: Expired due to Term

• Current Assignee: Rheox Incorporated Highstown NJ
• Original Assignee: NL Industries Incorporated (Valhi Holding Company)
• Inventors: Herman, Daniel F., Kruse, Uno
• Primary Examiner(s): Kendell, Lorraine T.
• Application Number:
  US06/217,495
• Time in Patent Office: 377 Days
• Field of Search: 428/375, 428/378, 428/379, 428/383, 428/372, 428/377, 174/23 C, 174/23 R, 526/312, 526/317
• US Class Current: 174/23.00C
• CPC Class Codes: H01B 7/288 using hygroscopic material or material swelling in the presence of liquid
• CPC Class Codes: Y10T 428/2927 including structurally defined particulate matter
• CPC Class Codes: Y10T 428/2936 Wound or wrapped core or coating [i.e., spiral or helical]
• CPC Class Codes: Y10T 428/2938 Coating on discrete and individual rods, strands or filaments
• CPC Class Codes: Y10T 428/2947 Synthetic resin or polymer in plural coatings, each of different type

Abstract

Insulated electrical devices protected against entry and migration of water, said electrical devices containing solid water-swellable, water-insoluble polymers prepared by crosslinking an olefinically-unsaturated carboxylic acid with an alkyl acrylate.

Claims

1. An electric cable having a core of a plurality of insulated conductors and a jacket, the area between the conductors and within the jacket being at least partially filled with a particulate water-swellable, water-insoluble polymer which comprises:

(a) from about 15% to about 50% by weight of an olefinically-unsaturated carboxylic acid containing an activated carbon-to-carbon olefinic double bond and at least one carboxy group;

(b) from about 49.07% to about 82% by weight of an alkyl acrylate wherein the alkyl group has from 1 to 6 carbon atoms; and

(c) from about 0.03% to about 3.0% by weight of a crosslinking agent which are polyunsaturated polymerizable vinyl monomers containing two or more free radical polymerizable ethylenic groups, said crosslinking agent being introduced directly into the carbon-carbon backbone of the polymer.

2. The electrical cable of claim 1 in which the polymer comprises from about 20% to about 40% by weight of the olefinically-unsaturated carboxylic acid selected from the group consisting of methacrylic acid and acrylic acid;

from about 59.02% to about 78% by weight of an alkyl acrylate selected from the group consisting of methyl acrylate, ethyl acrylate and n-butyl acrylate; and

about 0.08% to about 2% by weight crosslinking agent.

3. The electrical cable of claim 1 wherein the polymer is contained in an absorbent wrapping comprising an absorbent layer containing up to 90% by weight of said particulate water-swellable, water-insoluble polymer.