Abstract: Magnet wire is insulated with a paper insulation sheet which is longitudinally wrapped onto the wire. The paper sheet is precoated on one side with a layer of resinous adhesive dielectric material such as a thermoplastic polyester. The outside surface of the paper sheet has the resinous coating applied thereto and solidified prior to the time that the paper is wrapped onto the wire. Just prior to applying the paper to the wire, an edge of the resin coating is heated sufficiently to locally remelt the resin. The remelted edge is then overlapped by the opposite edge as the coated paper is wrapped onto the wire, whereby the edges of the insulation sheet are adhered together. The wrapped wire is then passed through one or more heated dies in order to remelt the entire resin coating, which remelted coating is then drawn back over the exterior of the paper layer. The wrapped wire is then passed through a water quench bath.

Abstract: A composite tape for forming at least part of the insulation of a high voltage electrical cable, particularly an oil-filled cable, and a cable including such insulating tape. The composite tape includes at least one layer of paper tape having a borate or silicate weight content in the range form 0.1 to 3% of the weight of the paper bonded to at least one surface or the surfaces of a film of bi-oriented polymeric plastic material by a copolymer layer which has a thickness of from about 1-10 microns. The thickness of all the plastic material in the composite tape is in the range from 10 to 30% of the total thickness of the tape. Preferred polymeric materials are polypropylene and polymethylpentene. A bonding material can be propylene-ethylene copolymer.

Abstract: The invention relates to a hydroexpansible composite material, the method of preparing same and a composition for implementing this method, as well as to the uses thereof. The composite material includes a solid flat support having, on at least one of its faces, a coating with a high proportion of a hydroexpansible polymer powder fixed to the support by means of a hydrosoluble binder, the coating being essentially formed of:95 to 55% by weight of hydroexpansible polymer powder;5 to 23% by weight of hydrosoluble binder; and0 to 22% by weight of surfactant.This hydroexpansible material may advantageously be used in medicine, surgery agriculture and especially as sealing agent in cables, particularly electric cables.FIG. 2 shows how, in a cable, this material (11, 13) forms a sealing ring (13) about the point of infiltration of the water, thus preventing its longitudinal propagation.

Abstract: Provision of a protective cover for a fibrous layer of insulation on a conductor by forming an inner layer of the protection cover by depositing a polymeric based composition without creating a crushing effect, and then, in tandem, hardening the inner layer and applying a second coat by extrusion. The inner layer absorbs the crushing forces of extrusion to protect the fibrous layer during addition of the second layer. The inner layer is preferably formed by electrostatic deposition coating and prevents pinhole formation in the second layer.

Abstract: The present invention relates to a laminated insulating paper formed of cellulose paper or papers which is adhered to at least one side of cross-linked silicone grafted polyolefine film and to an oil-filled (OF) cable which insulated by the laminated insulating paper. The laminated insulating paper has outstanding peel strength as well as excellent non-solubility and anti-swelling properties in insulating oils.

Abstract: An insulated electrical conductor comprising a core carrying an inner coating of heat resistant material and a uniform outer coating of fused polymeric material forming a smooth pin-hole free surface.