Raychem Limited

Other

Hans E Lunk

Ashok K Mehan

Stephen L Tondre

Phu D Nguyen

James M O'Brien

Donald A Reed

Albert R Martin

Rajendra S Cornelius

Mark D Mendenhall

Andrew N Au

Alan S Yeung

Marguerite E Deep

Timothy S Smith

Steven C Zingheim

Neal Enault

Charles Hill

This invention relates to flat cables comprising a plurality of substantially parallel insulated conductors bonded to a polymeric substrate which has a melting point greater than 200.degree. C. and/or a thickness less than 2.5 mils (98 microns) and a method for the production of such cables.

Flat cable

This invention relates to flat cables comprising a plurality of insulated conductors bonded to a porous substrate. The porous substrate is impregnated with a polymeric material capable of bonding to the insulation of the conductors. The strength of the bond can be varied by varying the amount of the impregnant. If it is desired to separate one or more of the conductors from the substrate, for example to form a branch off, a minimum amount of impregnant can be used.

This invention relates to flat cables comprising a plurality of insulated conductors bonded to a metallic substrate. The metallic substrate is provided with a layer of polymeric material capable of bonding to the insulation of the conductors. The layer of polymeric material is bonded to the metallic substrate with a peel strength of at least about 1 pound per linear inch (pli). The insulated conductors are bonded to the layer of polymeric material. The bond strength between the insulated conductors and the layer of polymeric material and the bond strength between the layer of polymeric material and the metallic substrate are such that the individual insulated conductors can be cleanly peeled away from the substrate.

Compositions containing at least about 30% of a poly(alkylene terephthalate), at least about 3% of a polylactone, about 0.05% to about 10% of a carbodiimide and at least about 0.05% to about 10% of an aliphatic phosphite, all percentages being by weight based on the weight of the composition, has excellent thermal stability. The compositions are useful for wire insulation and cable jacketing. Heat recoverable articles, such as tubing and molded parts can be prepared from the compositions.

Stabilized polymeric compositions

Shaped articles of cross-linked polymers comprising a first component having little or no cross-linking and high elongation, and a second component having a relatively high level of cross-linking and low elongation. Such articles are particularly useful in the form of electrical insulation, the first component being adjacent to a wire or other conductor. Preferably each of the components comprises a crystalline fluorocarbon polymer, especially an ethylene/tetrafluoroethylene copolymer. Such articles can be prepared by (1) melt-extruding a first polymeric composition which contains little or no cross-linking agent, and a second polymeric composition which contains a greater amount of cross-linking agent, (2) maintaining the two extrudates under conditions such that cross-linking agent migrates from the second to the first composition, and (3) cross-linking both compositions, preferably by radiation.

An electrical conductor insulated with meit-processed, cross-linked

When metal conductors are stored, especially in humid environments, their solderability decreases. The rate at which solderability decreases can be reduced by treating the conductor with a suitable surface active agent, particularly one which has an HLB (hydrophile-lipophile balance) number of less than 10, preferably less than 5. The surface active agent can be applied to the conductor with a suitable liquid carrier, e.g. as a solution in a mineral oil or a halogenated hydrocarbon. If desired, a polymeric insulating jacket can be melt-extruded or wrapped over the treated conductor.

Metal conductors with improved solderability

Melt-shapeable polymeric compositions comprising a first fluoropolymer of relatively low crystallinity, e.g. a copolymer of tetrafluoroethylene and a perfluorinated comonomer, and a second fluoropolymer of relatively high crystallinity, especially a fluoropolymer obtained by irradiating PTFE or another fluoropolymer which cannot be melt-shaped in the absence of other polymers. The weight ratio of the first to the second polymer is preferably 0.3:1 to 2.5:1. The compositions have a wide variety of uses, for example as insulating materials or, if they contain carbon black or another conductive filler, as PTC conductive polymers.

Melt-shapeable fluoropolymer compositions

Electrical insulation comprises (1) an inner layer of a cross-linked polymer, e.g. polyethylene, an ethylene/tetrafluoroethylene copolymer, an ethylene/chlorotrifluoroethylene polymer or a vinylidene fluoride polymer, and (2) an outer layer of an aromatic polymer having a glass transition temperature of at least 100.degree. C., e.g. a polyether ether ketone, a polyether ketone or a polyether sulfone. Such insulation combines excellent properties under normal service conditions with low smoke evolution on burning, and is therefore particularly useful for aircraft wire and cable.

Electrical insulation

Foamed polymers having low loss at microwave frequencies are prepared through use of perfluorinated alkane foaming agents. The invention is particularly valuable for polymers which are melt-processed at high temperatures, especially fluoropolymers such as tetrafluoroethylene copolymers. The polymeric foams are particularly useful as electrical insulation, especially for coaxial cables suitable for use at microwave frequencies.

Foamed fluoropolymer articles having low loss at microwave frequencies

Disclosed is a high frequency attenuation core and cable. The core includes a conductor surrounded by a high frequency energy absorbing medium, then surrounded by a dielectric, and then surrounded by an outer layer made from a material having a high complex dielectric constant. The cable includes the above described core surrounded by an electromagnetic interference (EMI) shield which is further surrounded by a conductive layer. The cable and core as described above may be used in harness applications wherein a plurality of cores and/or cables as described above are surrounded by a gross shield. In addition, when the cores described above are used in multi-core applications, they may individually include an additional EMI shield for greater electromagnetic interference protection.

High frequency attenuation core and cable

New polymeric compositions based on polytetramethylene terephthalate (PTMT) polymers are disclosed. PTMT polymers are subject to embrittlement, especially at elevated temperatures and when a flame retardant is incorporated therein. This problem is substantially reduced by blending the PTMT polymer with a second polymer which has a flex modulus of 500 to 100,000 psi and a solubility parameter within .+-.1.5 of the PTMT polymer, for example an ethylene/vinyl acetate copolymer or a block copolymer containing polyether and polyester blocks. The compositions are particularly useful as wire insulation.

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Menlo Park, CA, United States of America

Hans E Lunk