Study on preparation and performance of carboxylic-type waterborne polyurethane dispersion

The carboxylic-type waterborne polyurethane(WPU) dispersions were made from polybutylene glycol adipate(PBA3000),isophorone diisocyanate(IPDI) and dimethylol propionic acid(DMPA) as main raw materials.The results showed that the characteristics of WPU dispersions and films synthesized by one-step method were similar than those by two-step method,but one-step method was more convenient.The viscosity and conductivity of WPU dispersions,tensile strength,water absorption and hardness of WPU films were increased,but elongation at break of WPU films and particle diameter(100 nm) in dispersion were decreased when the mass fraction of-COOH group was increased.The tensile strength and hardness of WPU films were increased,but the viscosity of WPU dispersions,elongation at break and water absorption of WPU films were decreased when the R value was increased and the molar ratio of n(PBA)∶n(DMPA) was 2∶3.The WPU dispersions had well stability when mass fraction of-COOH group was between 1.09% and 2.37%.