Effects of formulation on set-to-touch time of waterborne alkyd resin by uniform design

In order to optimize the formulation of waterborne alkyd resin preparation, a 9-level-3-factor uniform design and regression analysis were firstly employed to evaluate the effects of the selected variables including fatty acid content (L), hydroxyl/carboxyl molar ratio (r) and molar ratio of polyatomic acids (f) on set-to-touch time of film. The results indicate that the data can be adequately fitted with a first-order polynomial model, and the main factors successively affecting set-to-touch time are fatty acid content (L) and molar ratio of polyatomic acid (f). The above model is proved valid within the designed scopes of the investigated formulation parameters by validation experiments. The optimized formulation parameters for waterborne alkyd resin synthesis is predicated as follows according to the model, i.e. L is 30%, r is 1.2, f is 2.2, the result set-to-touch time is 43 min, which significantly shorten the drying time.