Low-temperature curing polyamide-imide varnish as well as preparation method and application thereof

The invention provides a low-temperature curing polyamide-imide varnish and a preparation method and application thereof.The polyamide-imide varnish is prepared from aromatic tricarboxylic acid anhydride, aromatic diisocyanate and a compound organic solvent, and the compound organic solvent comprises a first organic solvent and a second organic solvent, the first type of organic solvent comprises any one or a combination of at least two of dimethyl sulfoxide, N-dimethylacetamide, N-methyl pyrrolidone or gamma-butyrolactone, and the second type of organic solvent comprises aliphatic polyester and/or aliphatic cyclic ketone; by selecting the specific parts of the compound organic solvent, the obtained polyamide-imide varnish has long-term storage stability and lower curing temperature, and meanwhile, a paint film formed after curing also has excellent limit performance and mechanical performance. 本发明提供一种低温固化的聚酰胺酰亚胺清漆及其制备方法和应用，所述聚酰胺酰亚胺清漆的制备原料包括芳香族三羧酸酐、芳香族二异氰酸酯和复配有机溶剂，所述复配有机溶剂包括第一类有机溶剂和第二类有机溶剂，所述第一类有机溶剂包括二甲基亚砜、N-