Polyamide-imide insulating varnish and preparation method thereof

The invention relates to a polyamide-imide insulating varnish. The polyamide-imide insulating varnish is characterized in that the varnish comprises the following components in parts by weight: 100-120 parts of polyamide-imide solution and 2-5 parts of sepiolite material, wherein the polyamide-imide solution mainly comprises the following components in parts by weight: 20-35 parts of polyamide-imide resin and 20-60 parts of organic solvent; the organic solvent is one or a combination of N-methylpyrrolidone, chlorobenzene, bromobenzene, dichlorobenzene, dibromobenzene, 1-tetralone, fenchone, phorone and isophorone; and the sepiolite material mainly comprises sepiolite. The polyamide-imide insulated enamel wire provided by the invention forms a homogeneous stable system, the surface friction coefficient is below 0.30, and each index meets the International Electrotechnical Commission (IEC) standard requirement; and the polyamide-imide insulating varnish is suitable to be used as the enamel wire insulating varni