High voltage insulating materials
AssigneeRaychem Corporation
InventorRichard J. Penneck
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Abstract
Tracking is reduced in insulators comprising one or more polymers and an anti-tracking filler system comprising (a) a hydrate of alumina having a specific surface area of at least 2 m.sup.2 /g measured by the BET method, and (b) a compound selected from the group consisting of oxides, mixed oxides and mixtures of oxides wherein said compound contains at least one element selected from the group consisting of transition series elements, lanthanide series elements and nontransuranic actinide series elements.
Claims40
Electrically insulating material suitable for high voltage applications which comprises one or more polymers and from about 29% to about 75% by weight of an anti-tracking filler system comprising:
- (a) a hydrate of alumina having a specific surface area of at least about 2 M.sup.2 /g, measured by the BET method, and (b) a compound selected from the group consisting of oxides, mixed oxides, and mixtures of oxides, wherein said compound contains at least one element selected from the group consisting of transition series elements, lanthanide series elements, and nontransuranic actinide series elements, components (a) and (b) being present in said anti-tracking filler system in amounts such that said electrically insulating material has an initial tracking voltage of at least about 2.5 kilovolts when tested according to ASTM-D 2303-68 liquid Contaminant Inclined Plane test.
Dependencies are inferred from the claim text.