| 摘要 |
A wire-coating composition comprises a polyvinyl acetal, e.g polyvinyl formal plus a phenolic resin and optionally a melamine-aldehyde resin and a polyurethane. Minor amounts of polyesters and epoxy resins may also be included.ALSO:A metal conductor is coated with a plurality of layers of a cured polyvinyl acetal resin composition and of a polyimide composition comprising the cured condensation product of an aromatic tetracarboxylic acid with an aromatic diamine containing from 6-16 carbon atoms or a saturated aliphatic diamine containing up to 6 carbon atoms. The polyvinyl acetal composition may also contain phenol - aldehyde resins, melaminealdehyde resins or polyurethanes. The polyimide coatings may be produced by applying polyamides and heating these to convert them to polyimides. Preferably four coats of the acetal resin and two of the polyimide are applied. Best results are obtained when the polyacetal resin is applied first. In the examples copper wire is coated by dipping in the resins, being cured after each application. |
