E.i. Dupont De Nemours and Company

Peter J Hollberg

Mikhail R Levit

Roger Curtis Wicks

Bruce A Yost

Xun Ma

Layton T Hulette

Brian Keith Trask

Brian P Little

James C Swann

This invention relates to a laminate electrical insulation part for an electrical device comprising a thermoplastic film positioned between, adjacent to, and attached to two nonwoven sheets. Each of the nonwoven sheets consists of multicomponent polymeric fibers comprising at least a first polymer and a second polymer, the first polymer having a melting point that is at least 15 degrees Celsius lower than both the melting point of the second polymer and the melting point of the thermoplastic film, and the film is attached to the nonwoven sheets by the first polymer in the nonwoven sheets. The electrical insulation part has a breakdown voltage of at least 3 kilovolts, and a surface having a dynamic frictional coefficient of 0.25 or less. This invention also relates to an electrical device component comprising the laminate electrical insulation part.

Laminate electrical insulation part

Use of a headbox with an auxiliary blade having a concave edge reduces the deflection required to modify the basis weight profile of a wet sheet formed in papermaking apparatus.

Headbox with concave auxiliary blade

Disclosed is an elongate, nonwoven flexible sheet structure and a method for its manufacture. The sheet structure consists essentially of a commingled mixture of about 45 to about 70% by weight short fibers of aromatic polyamide and about 30 to about 55% by weight fibrids of poly(meta-phenylene isophthalamide). The sheet structure has an interior thickness remote from the edges of between about 75 and about 150 microns with a thickened area along and adjacent each of the side edges having a maximum thickness which is at least about 5% greater in average thickness than the interior thickness of the sheet along and adjacent the thickened areas.

Aromatic polyamide paper with thickened edge areas and process for

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Richmond, VA, United States of America

Peter J Hollberg