The invention discloses a polyhydroxyalkanoate water-based
coating composition with a multiphase structure as well as a preparation method and application of the polyhydroxyalkanoate water-based
coating composition, and belongs to the technical field of macromolecular bio-based packaging materials and paper-based
coating. The composition is a working solution obtained by mixing a basic solution and a water-based cross-linking agent and then adjusting the pH value and the
solid content, the pH value of the working solution is 7.2-9.0, the
total solid content is 25.0 wt%-50.0 wt%, and the median particle size D50 is 200-500 nm; based on the total
mass of the specific non-volatile matter, the
plasticizer is 5.0 wt%-7.0 wt%, the water-based cross-linking agent is 2.5 wt%-4.0 wt%, the coating auxiliary agent is 0.5 wt%-1.0 wt%, and the dry
solid mass ratio of the polyhydroxyalkanoate
polymer to the auxiliary resin is 22: 78-62: 38. The composition is suitable for single-layer and single-time coating of a paper-based material, and the obtained coating has good
water resistance,
moisture resistance and folding resistance.