Preparation Of Styrene-acrylate Emulsion And Latex Coatings With Excellent Scrub Resistance

High pigment volume ratio(PVC) latex paint is an important part of interior architectural coatings. However, its emulsion content is so low that its scrub resistance is poor. And some components of paints contains formaldehyde and VOC, these will release and harm for people’s health.In this paper, styrene-acrylic emulsions with excellent scrub resistance were studied and synthesized. The factors that influence the scrub resistance of styrene-acrylic emulsions were investigated systematically. The results showed that the polymer glass transition temperature(Tg), polymerization method,type and content of emulsifiers, MAA and WE010 content and adding process had great influence on scrub resistance of styrene-acrylic emulsions films. Styrene-acrylic emulsions with excellent scrub resistance could be obtained under the optimized conditions: Synthesis by core-shell polymerization process, copolymer Tg is 20 ℃, Tg shell is 25 ℃, preferably anionic emulsifier alcohol polyoxyethylene ether succinate disodium and 2-acrylamidereactive emulsifier 2-methylpropane suffocate complex, with a total amount of 2% and the mass ratio of 1: 1, the carboxyl functional monomer MAA and a silane coupling agent WE010 total amount of 4% by mass ratio of 5: 1. MAA was added after dropping the main monomer, WE010 was added after the emulsion was cooled to room temperature.Modify the emulsion to reduce the free formaldehyde content of it. The results showed that MEEU could reduce the free formaldehyde content and improve the film wet adhesion and scrub resistance of emulsion. Styrene-acrylic emulsions with excellent scrub resistance and low free formaldehyde could be obtained when the MEEU amount is 2%.Finally, a high PVC and environmental friendly interior wall coatings was prepared with the self-made styrene-acrylic emulsion. The effects of types and content of fillers and additives on the properties of coatings were studied. The results show that increasing the amount of titanium dioxide and calcined kaolin can improve the contrast ratio of the film; Kaitai-powder can improve the scrub resistance and freeze-thaw stability of coating; Proper wetting agents and dispersing coalescent added content can improve the properties of coating. Interior wall coatings prepared showed high comprehensive properties, its scrub resistance was more than 1500 times,and amount of VOC and formaldehyde were extremely low.