Aircraft window
First Claim
1. An aircraft window comprising:
- a transparent substrate having an outer surface;
a thin, transparent conductive coating overlaying the substrate'"'"'s outer surface; and
a transparent polyurethane layer overlaying the transparent conductive coating, wherein the polyurethane layer is formed from a composition incorporating 0.5 to 5.0 weight percent of an ionizable salt of a perfluoroalkylsulfonimide.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention is embodied in a polyurethane composition suitable for coating, casting or laminating, which incorporates a prescribed additive selected to increase the composition'"'"'s electrical conductivity without adversely affecting the composition'"'"'s transparency and percent haze and without adversely affecting its adhesion to an underlying substrate or its environmental durability, especially with regard to humidity resistance. The prescribed additive is an ionizable metal salt of a perfluoroalkylsulfonimide, in a weight percent of 0.5 to 5.0, with the metal being an alkali metal and the preferred perfluoroalkylsulfonimide being trifluoromethanesulfonimide. The most preferred salt is lithium trifluoromethanesulfonimide. The preferred polyurethane include both aliphatic polyetherurethanes and aliphatic polyesterurethanes. Use of the additive enhances the composition'"'"'s electrical conductivity by at least about two orders of magnitude, thereby minimizing the risk of a static building to a point where a shock hazard is created or the polyurethane coating or laminate is damaged by a rapid discharge of electrical current. The composition is particularly useful in an aircraft window or transparency, where it can be used as a coating or laminated film overlaying a transparent conductive coating.
19 Citations
12 Claims
-
1. An aircraft window comprising:
-
a transparent substrate having an outer surface;
a thin, transparent conductive coating overlaying the substrate'"'"'s outer surface; and
a transparent polyurethane layer overlaying the transparent conductive coating, wherein the polyurethane layer is formed from a composition incorporating 0.5 to 5.0 weight percent of an ionizable salt of a perfluoroalkylsulfonimide. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
the transparent polyurethane layer comprises a transparent underlayer functioning as an adhesive layer, and a transparent overlayer; and
both the underlayer and the overlayer of the transparent polyurethane layer incorporate the ionizable salt of a perfluoroalkylsulfonimide.
-
-
11. An aircraft window as defined in claim 10, wherein:
-
the underlayer of the transparent polyurethane layer is a polyetherurethane sheet having surfaces carrying the ionizable salt of a perfluoroalkylsulfonimide; and
the overlayer of the transparent polyurethane layer is an aliphatic polyesterurethane incorporating the ionizable salt of a perfluoroalkylsulfonimide.
-
-
12. An aircraft window as defined in claim 1, wherein:
-
the transparent substrate is selected from the group consisting of polycarbonate, glass, and acrylic; and
the thin, transparent conductive coating is selected from the group consisting of gold, indium tin oxide, metal oxide, and multi-layer stacks thereof.
-
Specification