Aq. acrylic! and phenol!-formaldehyde! resin coating compsn. - for electrical conductors, giving good dielectric properties, retaining flexibility on ageing

摘要

The coating compsn. has solids content of 5-50%, consisting essentially of (A) 60-95 wt.% of a disposed acrylic polymer, comprising (1) 35-55 wt.% of acrylonitrile a methacrylonitrile (2) 15-58 wt.% of 2-12C alkyl acylate (3) 2-15 wt.% of (meth)acrylic and (4) 5-15 wt.% of a 1-6C alkoxy(alkoxymethyl)acrylamide, the polymer having wt. average mol.wt. is not 150,000 (esp. 3 x 105 to 3 x 106) and (B) 5-40 wt.% (esp. 15-25%) of phenol-formaldehyde (PF) condensate of wt. average mol.wt. 100-2,000 (esp. 150-1,000) with enough NH2OH or amine to give pH 7.0-9.5 (esp. 8.0-9.5). The compsn. also desirably contains 0.5-5% of a 2-8C alkyleneglycol, 0.5-5% of a long-chain fatty acid salt (as defoamer) and 1-10% of a polyacrylic acid thickener. The compsn. is particularly useful for coating wires and other electrical conductors of Al, Cu, Al alloys, etc. The compsn. has good dielectric props. and retains its flexibility on ageing. When used as a coating on wires it can withstand surges of high electrical voltage under elevated temps. of less excellent resistance to insulating liqs. used in transformer.