Water-based hydroxyl-containing polyester dispersion for automobile paint and preparation method thereof

The invention discloses water-based hydroxyl-containing polyester dispersion resin for top coating in automobile paint, which is characterized by being prepared from the following six parts: 1 to 10 parts of a solvent, 10 to 40 parts of active polybasic carboxylic acid monomer, 10 to 40 parts of an active polybasic hydroxyl monomer, 1 to 10 parts of trimellitic anhydride, 0.5 to 10 parts of a neutralizer and 30 to 60 parts of deionized water. The invention also discloses a preparation method of the water-based hydroxyl-containing polyester dispersion resin. The preparation method comprises thefollowing steps: reacting polycarboxylic acid with polyol to synthesize polyester resin with hydroxyl, adding trimellitic anhydride to provide hydrophilicity, adding a neutralizer to neutralize, andemulsifying and dispersing with water to obtain the water-based hydroxyl-containing polyester dispersion resin. The water-based hydroxyl-containing polyester dispersion provided by the invention is good in resin stability, low