| 摘要 |
Electrical conductors are coated by applying thereto at least one layer of an aqueous dispersion of a copolymer of (i) 50 to 80% by weight of acrylonitrile, (ii) at least 10% by weight of a C1-C12 aliphatic monohydric alcohol ester of acrylic or methacrylic acid, and (iii) 0,1 to 15% of a monoethylenic carboxylic acid amide, or an N-methylol derivative of such an amide, or a Mannich base of an N-methylol ether of such an amide, or an acrylic or methacrylic acid amide of an aminobenzoic acid, and then heating the layer to a temperature of 100 DEG to 300 DEG C. The copolymers may contain minor proportions of other monomers. Also present in the coating compositions may be solvents, eg. dimethyl formamide, glycol carbonate and tetramethylene sulphone, and a water-soluble phenol formaldehyde resin. The electrical conductor, e.g. a wire, may be coated by a process which involves conveying it through the copolymer a plurality of times and hardening the resulting layer by passing the wire through a drying shaft having a temperature of 280 DEG to 300 DEG C, at a withdrawal speed of six to ten metres per minute. The examples describe the application to copper wire of aqueous dispersions comprising: (1) an acrylonitrile-butyl acrylate-methacrylamide copolymer and dimethyl formamide; (2) an acrylonitrile-butyl acrylate-methacrylic acid-methacrylamide copolymer and dimethyl formamide; (3) an ammonia-neutralized copolymer of acrylonitrile, butyl acrylate, methacrylic acid and the methyl methylol ether of methacrylamide; (4) an ammonia-neutralized copolymer of acrylonitrile, butyl acrylate, methacrylamide and the methacrylic amide of p-aminobenzoic acid, dimethyl formamide and a water-soluble phenol-formaldehyde resin; and (5) an ammonia-neutralized copolymer of acrylonitrile, butyl acrylate, methacrylamide and the methacrylic amide of o-aminobenzoic acid, dimethyl formamide and a water-soluble phenol-formaldehyde resin. |
