Abstract: Polymeric compositions which contain a thermoplastic aromatic polyester, preferably polybutylene terephthalate, and a polyester block copolymer having a recrystallization temperature greater than 150.degree. 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.

Abstract: Novel polyester compositions, particularly suitable for the insulation of wires, contain an aromatic polyester, especially polybutylene terephthalate. The presence of certain tin (II) compounds, for example tin (II) oxide, oxalate, phthalate, pyromellitate, or phosphite, reduces the flammability and smoke generation of such compositions. The presence of an aliphatic polyester, and optionally a thermoplastic elastomer, can also improve the properties of such compositions.

Abstract: Compositions containing at least about 30% of a poly(alkylene terephthalate), at least about 3% of a polylactone, about 0.05% to about 10% of a carbodiimide and at least about 0.05% to about 10% of an aliphatic phosphite, all percentages being by weight based on the weight of the composition, has excellent thermal stability. The compositions are useful for wire insulation and cable jacketing. Heat recoverable articles, such as tubing and molded parts can be prepared from the compositions.

Abstract: Electrical insulation comprises (1) an inner layer of a cross-linked polymer, e.g. polyethylene, an ethylene/tetrafluoroethylene copolymer, an ethylene/chlorotrifluoroethylene polymer or a vinylidene fluoride polymer, and (2) an outer layer of an aromatic polymer having a glass transition temperature of at least 100.degree. C., e.g. a polyether ether ketone, a polyether ketone or a polyether sulfone. Such insulation combines excellent properties under normal service conditions with low smoke evolution on burning, and is therefore particularly useful for aircraft wire and cable.

Abstract: Electrical insulation comprises (1) an inner layer of a cross-linked polymer, e.g. polyethylene, an ethylene/tetrafluoroethylene copolymer, an ethylene/chlorotrifluoroethylene polymer or a vinylidene fluoride polymer, and (2) an outer layer of an aromatic polymer having a glass transition temperature of at least 100.degree. C., e.g. a polyether ether ketone, a polyether ketone or a polyether sulfone. Such insulation combines excellent properties under normal service conditions with low smoke evolution on burning, and is therefore particularly useful for aircraft wire and cable.