ELECTRICALLY INSULATED WIRES AND CABLES
In a first aspect, an electrically insulated wire or cable includes a stranded conductor, an inner wrap around the stranded conductor and an outer wrap around the inner wrap. The inner wrap includes a base film tape, wherein the base film tape includes a polyimide film having an electrically insulative, corona resistant composite filler, a first fluoropolymer coating adhered to a first side of the polyimide film and a second fluoropolymer coating adhered to a second side of the polyimide film. The outer wrap includes a fluoropolymer tape. The electrically insulated wire or cable has a void space in a range of from 2 to 43%, based on the total space available inside the inner wrap.
1 . An electrically insulated wire or cable comprising:
a stranded conductor;
an inner wrap around the stranded conductor, the inner wrap comprising a base film tape, wherein the base film tape comprises:
a polyimide film having an electrically insulative, corona resistant composite filler;
a first fluoropolymer coating adhered to a first side of the polyimide film; and
a second fluoropolymer coating adhered to a second side of the polyimide film; and
an outer wrap around the inner wrap, the outer wrap comprising a fluoropolymer tape, wherein the electrically insulated wire or cable has a void space in a range of from 2 to 43%, based on the total space available inside the inner wrap.
2 . The electrically insulated wire or cable of claim 1 , wherein the stranded conductor comprises coated copper wire selected from the group consisting of nickel-coated copper alloy wire, tin-coated copper alloy wire and silver-coated copper alloy wire.
3 . The electrically insulated wire or cable of claim 1 , wherein the electrically insulative, corona resistant composite filler is present in an amount in a range of from 5 to 30 weight percent, based on the total weight of the polyimide film.
4 . The electrically insulated wire or cable of claim 1 , wherein the first fluoropolymer coating and the second fluoropolymer coating each individually comprises a fluoropolymer selected from the group consisting of tetrafluoroethylene-hexafluoropropylene copolymer, perfluoro alkoxy resin, polytetrafluoroethylene or a mixture thereof.
5 . The electrically insulated wire or cable of claim 4 , wherein the fluoropolymer of the first fluoropolymer coating and the fluoropolymer of the second fluoropolymer coating are each individually not crosslinked.
6 . The electrically insulated wire or cable of claim 1 , wherein the first fluoropolymer coating and the second fluoropolymer coating are the same or different.
7 . The electrically insulated wire or cable of claim 1 , wherein the fluoropolymer tape comprises polytetrafluoroethylene.
8 . The electrically insulated wire or cable of claim 1 , wherein the base film tape has a thickness in a range of from 25 μm to 40 μm as measured in the unwrapped state.
9 . The electrically insulated wire or cable of claim 1 , wherein the stranded conductor has less than 100 strands and a contact length between the inner wrap and the stranded conductor is in a range of from 15 to 69%.
10 . The electrically insulated wire or cable of claim 1 , wherein the stranded conductor has more than 100 strands and a contact length between the inner wrap and the stranded conductor is in a range of from 15 to 79%.
11 . The electrically insulated wire or cable of claim 1 , wherein the stranded conductor is a concentric multi-stranded conductor and has a contact length between the inner wrap and the stranded conductor is in a range of from 10 to 70%.
12 . The electrically insulated wire or cable of claim 1 , wherein the electrically insulative, corona resistant composite filler comprises an organic component and an inorganic ceramic oxide component.
13 . The electrically insulated wire or cable of claim 12 , wherein the organic component is an organo-siloxane moiety or an organo-metaloxane moiety.
14 . The electrically insulated wire or cable of claim 12 , wherein the inorganic ceramic oxide component is selected from the group consisting of silica, alumina, titania, zirconia and mixtures thereof.
15 . The electrically insulated wire or cable of claim 12 , wherein a weight ratio of the organic component to the inorganic ceramic oxide component is in a range of from 0.01:1 to 1:1.
16 . The electrically insulated wire or cable of claim 1 , wherein a thickness ratio of the first fluoropolymer coating to the polyimide film and a thickness ratio of the second fluoropolymer coating to the polyimide film are each individually in a range of from 0.01:1 to 0.5:1.
17 . The electrically insulated wire or cable of claim 1 , wherein the amount of overlap of the inner wrap does not exceed 66%.