Insulated electrical conductors
First Claim
1. An electrical assembly which comprises a hermetically sealed enclosure containing a refrigerant liquid and an insulated electrical wire which is within the enclosure and is contacted by the refrigerant, said insulated wire comprising a wire and, surrounding the wire, a layer of a melt-extruded electrically insulating composition which comprises a polymeric component comprising a blend of(1) a thermoplastic aromatic polyester which consists essentially of 70 to 100% by weight of tetramethylene terephthalate units and 0 to 30% of other units which are randomly copolymerized with the tetramethylene terephthalate units, and(2) a second polymer which has a recrystallization temperature greater than 150°
- C. and is a polyester block copolymer;
said blend having a ratio by weight of the second polymer to the aromatic polyester of from 0.05;
1 to 0.35;
1.
3 Assignments
0 Petitions
Accused Products
Abstract
Polymeric compositions which contain a thermoplastic aromatic polyester, preferably polybutylene terephthalate, and a polyester block copolymer having a recrystallization temperature greater than 150° C., preferably a thermoplastic elastomer containing aromatic polyester blocks and aliphatic polyester blocks. The ratio of the block copolymer to the aromatic polyester is 0.05:1 to 0.35:1, preferably 0.15:1 to 0.30:1. These compositions are particularly useful as the insulation on hermetic lead wires for use in refrigerant systems. To prevent cracking of such insulation when it is contacted by a varnish used to provide hermetic sealing, it can be covered by a thin layer of a fluoropolymer.
45 Citations
29 Claims
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1. An electrical assembly which comprises a hermetically sealed enclosure containing a refrigerant liquid and an insulated electrical wire which is within the enclosure and is contacted by the refrigerant, said insulated wire comprising a wire and, surrounding the wire, a layer of a melt-extruded electrically insulating composition which comprises a polymeric component comprising a blend of
(1) a thermoplastic aromatic polyester which consists essentially of 70 to 100% by weight of tetramethylene terephthalate units and 0 to 30% of other units which are randomly copolymerized with the tetramethylene terephthalate units, and (2) a second polymer which has a recrystallization temperature greater than 150° - C. and is a polyester block copolymer;
said blend having a ratio by weight of the second polymer to the aromatic polyester of from 0.05;
1 to 0.35;
1. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- C. and is a polyester block copolymer;
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8. An electrical assembly which comprises a hermetically sealed enclosure containing a refrigerant liquid and an insulated electrical wire which is within the enclosure and is contacted by the refrigerant, said insulated wire comprising a wire and polymeric insulation which surrounds the wire, the insulation comprising
(A) an inner layer composed of a first melt-extruded polymeric composition which comprises a polymeric component which comprises a blend of (1) a thermoplastic aromatic polyester which consists essentially of 70 to 100% by weight of tetramethylene terephthalate units and 0 to 30% of other units which are randomly copolymerized with the tetramethylene terephthalate units, and (2) a second polymer which has a recrystallization temperature greater than 150° - C. and is a polyester block copolymer;
said blend having a ratio by weight of the second polymer to the aromatic polyester of from 0.05;
1 to 0.35;
1; and(B) an outer layer composed of a second melt-extruded polymeric composition which comprises a polymeric component which consists essentially of one or more fluoropolymers. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
- C. and is a polyester block copolymer;
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16. An electrical assembly which comprises a hermetically sealed enclosure containing a refrigerant liquid and an insulated electrical wire which is within the enclosure and is contacted by the refrigerant, said insulated wire comprising a wire having an outside diameter of 0.116 to 0.029 inch (2.95 to 0.737 mm, 10 to 22 AWG) and polymeric insulation which surrounds the wire, the insulation consisting of
(A) an inner layer which contacts the wire, which is 0.006 to 0.02 inch thick and which is composed of a first melt-extruded polymeric composition which comprises (i) a polymeric component which consists essentially of a blend of (1) polybutylene terephthalate, and (2) a second polymer which has a recrystallization temperature greater than 150° - C. and which is a thermoplastic elastomer which comprises;
(a) 70 to 90% by weight of aromatic polyester blocks in which repeating units have a formula (I)
space="preserve" listing-type="equation">--O--(CH.sub.2).sub.p --O.CO.Ar.-- (I)wherein p is 4 and Ar is a 1,4-phenylene radical, and (b) 10 to 30% by weight of aliphatic polyester blocks in which the repeating units have the formula (II)
space="preserve" listing-type="equation">--O--(CH.sub.2).sub.q --O.CO.--(CH.sub.2).sub.r --CO-- (II)wherein each of q and r is 4; the ratio by weight of the thermoplastic elastomer (2) to the polybutylene terephthalate being from 0.15;
1 to 0.30;
1; and(3) 0-20% by weight, based on the weight of the polybutylene terephthalate, of one or more other polymers; and (ii) 0 to 10% by weight, based on the weight of the composition, of non-polymeric ingredients; and (B) an outer layer which is 0.001 to 0.004 inch thick and which is composed of a second melt-extruded polymeric composition which consists essentially of (i) at least one fluorinated polymer selected from ethylene/chlorotrifluoroethylene polymers and ethylene/tetrafluoroethylene polymers, and (ii) 0 to 10% by weight, based on the weight of the composition, of non-polymeric ingredients.
- C. and which is a thermoplastic elastomer which comprises;
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17. An electrical assembly which comprises an electrical motor, an insulated lead wire for delivering electrical power to the motor, a housing which surrounds the motor, and a layer of a cured epoxy polymer varnish which hermetically seals the housing and which extends over at least part of the insulated lead wire, the lead wire (i), when subjected to a CFC extraction test, having less than 0.8% by weight extractables, and (ii) comprising a wire and polymeric insulation surrounding the wire, the insulation comprising
(A) an inner layer composed of a first melt-extruded polymeric composition which comprises a blend of (1) a thermoplastic aromatic polyester, and (2) a second polymer which has a recrystallization temperature greater than 150° - C. and is a polyester block copolymer; and
(B) an outer layer which is composed of a second melt-extruded polymeric composition comprising a fluoropolymer and which, when the varnish on the surface of the insulated wire cracks, prevents cracking of the varnish from causing cracking of the inner layer of insulation. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
- C. and is a polyester block copolymer; and
Specification