Preparation Of A Novel Aqueous Hydroxyfunctional Acrylic Dispersion And High PVC Two-component Water-borne Polyurethane Coatings

This paper includes two parts. Part one is the preparation of glycidyl ester ofversatic acid （E10P） modified aqueous hydroxyfunctional acrylic dispersion. Part twois study on high PVC two-component water-borne polyurethane white coatings.(1) A novel E10P modified hydroxyfunctional acrylic dispersion is perpared. Theinfluence of the way of introducing E10P, the way of adding acrylic acid, hydroxyl valueand Tgon the aqueous dispersion are studied. This acrylic dispersion has low VOC, lowviscosity, good stability and without extracting solvent. The structure, molecular weightand stability of product is characterized by FT-IR, GPC and LPSA. The result indicatesthat if TAPA is used as initiator, linear polymer which has low viscosity and narrowmolecular weight distribution can be obtained. Appropriate content of initiator is2.3~3.0%. When E10P is introduced during the process of preparing the acrylic resin, themolecule weight and molecular weight distribution coefficient of the resin is smaller, andthe particle size of dispersion is smaller, too. When acrylic acid is added in two steps, theparticle size of dispersion is smaller and particle size distribution is better. Beside, theresult shows hydroxyl value is higher, the time of surface dry is shorter, so is the primaryhydroxyl group/secondary hydroxyl group ratio. The glossiness and hardness of coatingsis higher if Tgis between17℃and26℃. The property of the coatings prepared with theresin modified by E10P is better than the coatings with the resin which is not modifiedby E10P in emulsifying property, chemical resistance character and mechanical property.(2) A hydroxyfunctional acrylic resin aqueous dispersion with phosphate group isprepared by solution polymerization with2-hydroxy ethyl methacrylate phosphate(HEMAP) and acrylic monomers. The particle size and particle size distribution ischaracterized by LPSA. The affection of the way of adding HEMAP and the quantity ofHEMAP on product is studied. The CPVC is determined by electrochemical test,abrasion performance test and contact angle test. The theory of increasing PVC byintroducing HEMAP is studied. The result shows it is the best way to preparehydroxylfunctional acrylic resin that adding acrylate and HEMAP together. When thecontent of HEMAP is2%~3%, the solids content of aqueous dispersion is higher,molecular weight and particle is smaller, the CPVC can be as high as40%, increasingabout10%. There maybe two reasons that increasing PVC by introducing HEMAP. Thefirst one is that introducing HEMAP can decrease the particle size of the aqueous dispersion. The second reason is the high polarity of HEMAP can improve the propertyof pigment adsorption of the hydroxyl aqueous dispersion.