Developing a novel environmental friendly polyester-imide impregnating resin

In this article, a novel environmental friendly polyester-imide impregnating resin was developed by combining polyester-imide, novel active cross-linking monomer and effective initiator-inhibitor system. The new resin has excellent processing abilities, suitable for usual dipping, VPI, and dip-rolling machines. The comprehensive performance of this new resin was investigated systematically, including curing reaction, volatile material content, bond strength, volume shrinkage rate, heat resistance, storage stability, application performance of impregnating mica tape, acute toxicity, and skin irritation. The results indicate that the new resin has many excellent characteristics, such as fast curing at low-temperature, very low volatile material content, low volume shrinkage rate, excellent bond strength and heat resistance above Class H temperature, excellent storage stability without cold storage, and good electrical insulation properties with mica tape as main wall insulation. The new resin can be used for both low and medium voltage rotating machines and transformers. It is an excellent substitution to common unsaturated polyester impregnating resins by complying with the global environmental policy, and has a significant effect on upgrading insulating impregnating resin products and environmental improvement of insulation impregnating in the areas of motors and electrical equipment industry.