Synthesis Of Styrene-acrylate Emulsion And Its Application For Waterborne Antirust Coatings

Waterborne coating is the demand of protecting environment and saving oil resource. Water is the main solvent of waterborne coating, it has became a leading development orientation of modern coatings because it is not only harmless to people and environment but also easy for application storage and transportation . at present, waterborne coating has been widely used as electrophoreticcoating and building coating, while limitedly used in antirust coatings, it is mainly because there are several problems in present waterborne antirust coatings including comparatively short antirust time, low disperse stability and flash rusting .In this paper, a moderate antirust coating is prepared by means of emulsion copolymerization using MMA,BA, St as main momomers, functional polymers as modified monomers, added with filler pigment and additives. The main work content are: (1) The latex is synthesized by means of emulsion copolymerization using MMA BA, St as main monomers. It is found that we got the emulsion with 45% solid content and 90nm average particle size when the emulsifier amount is 1.5 % of the total amount of monomers byweight-D (0.5%) /S-10 (0.5%) is in the core layer, and S-10 (0.5%)in the sell layer; the amount of redox initiator is 0.2% of the tatal amout of monomers by weight, added by step method with a proportion of 1:1.(2)Discusses the influence of compositions of rigid and soft monomers on the performance of latex and films, the best proportion of rigid and soft monomers is 1.22:1.(3) In non-crosslinking system, adding D1 in the core monomers by seed emulsion polymerization. It is found that film got the best attachment strength and water resistance when the amount of D1 is 2% of the tatal amout of core monomers by weight.(4) In crosslinking system, adding crosslinking monomers in the core or shell monomers by seed emulsion polymerization. It is found that latex and film got the best performance when the amount of A1 is 6%, H1 is 1-2%, C1 and B1 is 3% of the total amount of each layer by weight respectively.(5) Choose P as Functional Monomers. It is found that the coating can totally restrain flash rust , Ca²⁺ stability achieve 50ml when the functional phosphate monomers amount is 4 % of the total amount of shell layer by weight.(6)The resulted coating film has better antirust property, compared with conventional styrene-acrylate emulsion. It was no rusting and no blistering after NaCl solution (3% ) test for 400 hours, is followed on some society promotion value.