Raychem Limited

Paul B Germeraad

Alan J Gotcher

Randolph W Chan

Robert S Dubrow

James T Triplett

Viktors Jansons

Dennis C Siden

Michael L Jensen

Albert R Martin

Larry J White

Ted M Aune

Christine J Holland

This invention provides E.M.I. gaskets for electrically shielding and environmentally sealing the space between two surfaces which comprises a metallic electrically conductive deformable structure adapted for forming electrical contact with said surfaces and/or providing electrical shielding in the space between said surfaces; and a gel material for sealing the space between said surfaces having a cone penetration value of about 100 to about 350 (10.sup.-1 mm) and an ultimate elongation of at least 200% and being present in sufficient amount and positioned to provide environmental seal between said surfaces and to provide environmental protection for said metallic structure. The gel may encapsulate the entire metallic structure so that portions of the metallic structure pierces through the gel when the gasket is installed to make electrical contact. Alternatively portions of the metallic structure may extend beyond the surface of the gel and the gel deforms to cover exposed portions of the metallic structure when the gasket is installed. The gasket of this invention provides moisture seal and is resistant to corrosion.

Shielding and sealing gaskets

An electrical heater which includes a fabric prepared from electrodes and an elongate resistive heating element which is composed of a conductive polymer, preferably a PTC conductive polymer, to render the heater self-regulating. The fabric is laminated to, and preferably embedded in, a sheet of an insulating polymer, particularly a non-tracking insulating polymer.

Electrical devices comprising fabrics

An electrical heater which comprises a fabric prepared from at least one of the electrodes and another elongate element of substantially higher resistance. The heater preferably comprises a PTC element, e.g. of a conductive polymer, to render the heater self-regulating. The PTC element may be in the form of a fiber forming part of the fabric, or a layer surrounding one of the electrodes, or a laminar element in which the fabric is embedded. The fabric can if desired be laminated to a sheet of a polymer, e.g. an insulating polymer or a ZTC conductive polymer. A shrinkable fabric heater can be made by incorporating a heat-shrinkable non-conductive filament into the fabric, perpendicular to both electrodes, and is useful for example for enclosing splices in telephone cables.

Melt-processable fluorocarbon polymer compositions requiring high temperature processing can be highly crosslinked by exposure to radiation after post-extrusion incorporation of at least one of certain crosslinking agents. These polymer compositions can be crosslinked to exceptionally high levels affording polymeric materials of improved mechanical properties at elevated temperatures, especially when utilized in wire constructions.

Shaped article from crosslinked fluorocarbon polymer

Compounds useful as crosslinking agents have the formula: ##STR1## wherein R.sub.1, R.sub.2, and R.sub.3 and R.sub.4 are independently vinyl, allyl, methallyl, propargyl, crotyl, C.sub.1 to C.sub.18 alkyl, aryl or inert group substituted derivatives thereof and where X is a saturated or unsaturated alkylene moiety having up to 12 carbon atoms saturated or unsaturated C.sub.1 -C.sub.18 heteroaliphatic, C.sub.5 -C.sub.18 heteroaromatic, C.sub.5 -C.sub.18 alicyclic or C.sub.1 -C.sub.18 heterocyclic, where n and m are independently 0 or integers of from 1-12 inclusive. These compounds are particularly useful as crosslinking agents for high temperature processable (&gt;200.degree.) polymers, especially fluorocarbon polymers. Also described are polymer compositions comprising from about 0.1 weight percent to about 50 weight percent of said crosslinking agent or mixture of said crosslinking agents. The products resulting from melt fabrication and subsequent crosslinking of such compositions are useful as shaped articles, e.g., wire products. Most of said compounds are novel compositions of matter.

Shaped article of radiation crosslinked triazine-trione polymeric

Shaped article from crosslinked fluorocarbon polymer and process therefor

A composition comprising a polymer having a processing temperature of at least 200.degree. and from about 0.1 wt % up to about 30 wt % of crosslinking agent said crosslinking agent comprising a compound of the formula ##STR1## wherein X is hydrogen and Y is ##STR2## and X and Y are substituents on adjacent carbon atoms of A or wherein X and Y together form the imide ring system ##STR3## which is joined to A on adjacent carbons atoms, thereof, wherein A is an aromatic, heteroaromatic, alicyclic, or heterocyclic system or an open chain aliphatic moiety, where R is vinyl, allyl, methallyl or propargyl and wherein R' is hydrogen, C.sub.1 to C.sub.12 alkyl or R and mixtures thereof. Compounds per se and articles manufactured from the above-indicated polymer compositon are also taught.

Growing community of inventors

Palo Alto, CA, United States of America

Paul B Germeraad