The novel ultraviolet curable waterborne polyurethane (UVWPU) was synthesized by using iso-phorone diisocyanate (IPDI),polyethylene glycol (PEG,Mw=600),α,α-dimethylol propionic acid (DMPA) and bisphenol A.The rigid moiety was introduced into the polyurethane main chain to improve the heat resistance.The copolymer structure was confirmed by FT-IR.The effect of the molar ratio of IPDI/ PEG600,dosage of DMPA and bisphenol A on the properties of latex and coating film were investigated.The results show that the storage stability of emulsion was longer than 6 months when the DMPA dosage was above 5.76％.With the DMPA dosage from 5.76％to 9.04％,the average particle diameter was decreased from 90.16 to 43.30μm.The UVWPU film exhibits good appearance and excellent properties when the molar ratio of IPDI/PEG600 was more than 3.4.The properties of the modified film were as follows: H of pencil hardness,1 of adhesion,5％weight-loss temperature at 233℃The temperature of 5％loss weight was 14℃ and the Tg was 7.07℃ higher than the UVWPU without using bisphenol A.The heat resistance,pencil hardness and adhesion of the film were improved by using bisphenol A as the chain extender.No change was found after placed the modified film at 100℃ with 200h.
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