Syntheticism Of Hydroxyl Acrylic Ester Emulsion Containing Phosphate Ester And Preparation Of Water-dispersible Polyisocyanate

Acrylate-polyurethane two components system polymers made from hydroxyl acrylate and polyisocyanate have good heat resistance, anticorrosion and adhesion, which have been widely used in anticorrosive coatings. When hydroxyl acrylate emulsion and hydrophilical polyisocyanate was applied in anticorrosion coatings, there are some difference between anticorrosive property of this kind of coatings and solvent coatings, because the traditional acrylate emulsion contains small molecule hydrophilical emulsifier. In order to improve anticorrosive property of this kind of coatings, the technologies of soap-soap-free emulsion polymerization and core-shell emulsion polymerization were used in this paper, hydroxyl acrylate emulsion containing phosphate ester was synthesized, and water-dispersible polyisocyanate was prepared by Non-ion modified technology. The effects of emulsion and curing agents on polymerization process have been discussed respectively. The effects of the mixing ratio of emulsifier, the adding amount of phosphite ester monomer, hydroxyl group's content and the adding amount of self-crosslinking monomer on emulsion and the properties of film-former were studied. The effects of molecular weight of epoxy-propane polyether and epoxy-ethane polyether, mole ratio of polyisocyanate group and hydroxyl group and the kinds of polyisocyanate on the dispersion and application of coatings during the preparation process of water-dispersible polyisocyanate was discussed. The result indicates that when adding shell and core monomers during the synthesis process of emulsion, the ideal polymer can be formed by "feeding-starving" method, and the gel fraction is low. The best amounts of compound emulsifier SDS and SE-10N are 0.6% and 0.9% respectively. The best amount of crosslinking monomer is 2% of the total adding amount. The water resistance and mechanical property of film former can be best when the content of hydroxyl group reaches 2%. Phosphate ester monomer adding into the emulsion can improve the stability of calcium ion, anti-flash etching property and the wet adhesion of the coating. When the adding amount reaches 4%, the coating has no flash etching. When the reaction temperature reaches 80℃during the preparation process of the water-dispersible polyisocyanate, the viscosity of the resulting product is moderate, and the content of the polyisocyanate is basically corresponding to the theoretical design. When the hydrophilical polyether was using 3 times feeding method, the reaction was relatively stable. Aliphatic polyisocyanate was used to prepare hydrophilical polyisocyanate, and its reaction ratio was moderate. When anticorrosion coatings was prepared, the anticorrosion and mechanical properties of the film were better than aromatic polyisocyanate. When the relative molecular mass of epoxy -ethane polyether is 400～600, the relative molecular mass of epoxy-propane polyether is 1000 and its equivalent ratio is 6:4, it was grafted with polyisocyanate, the viscosity of the resulting products is low, and it has good dispersion in coatings. Considering the dispersion of hydrophilical polyisocyanate in coatings and te anticorrosion property of the coatings, the best equivalent ratio of -NCO/-OH is 6.0.