Polyamide-Imide Precursor Solution PAI-15%

PAI (polyamide-imide) cured from PAI-15% precursor achieves IEC 60172 Thermal Class H (180°C) to Class C (>220°C continuous), with Tg >280°C. This positions PAI between standard Class F polyurethane enamels (155°C) and pure polyimide (PI, Tg >300°C Class C). PAI's advantage over PI is solubility in polar solvents (NMP, DMAc) as the polyamic acid precursor, allowing wire coating by conventional enameling towers at 300–450°C rather than PI's demanding melt processing. Compared to PI, PAI has better adhesion to copper wire (peel strength >1 N/mm), slightly lower dielectric constant (3.5 vs 3.1 for PI), and better thermal shock resistance. PAI is the dominant wire enamel for high-efficiency electric motor windings, turbine generator coils, and automotive EV traction motors.