Synthesis Of Cationic Acrylate Latex And Preparation Of Antibacterial Coatings

Acrylate emulsion is widely used in base resin because of its good weather ability,stable mechanical performance and low cost.The cationic acrylate latex not only has the excellent properties of its base material,but also has positive charge.On the one hand,it can be well combined with negative charge base material,to get good adhesion strength.On the other hand,because positive charge can inhibit bacteria and mold,so it can be applied as an antibacterial latex to architectural coatings.It conforms to the new concept of high decoration and functional in accord with architectural coatings.The functional monomers of quaternary ammonium salts with different carbon content were designed and synthesized.The antibacterial and pure acrylic polymer latex was copolymerized by emulsion polymerization.By comparing the properties and antibacterial properties of the latex to selected a polymer latex with excellent antibacterial properties.In the preparation of coatings,the influence of various auxiliaries on the properties of coatings is systematically studied.The main work of this paper includes the following aspects.1 Quaternary ammonium monomer synthesisThree kinds of antibacterial monomers with different carbon numbers were designed in this experiment.Acetone as solvent,were quaternidated to synthesize antibacterne monomers.Synthesis of QAMCA with 2-(N,N-dimethylamino)ethyl methacrylate(DMAEMA)and bromobutane.Synthesis of QAMCB with 2-(N,N-dimethylamino)ethyl methacrylate(DMAEMA)and 1-Bromododecane.Synthesis of QAMCC with 2-(N,N-dimethylamino)ethyl methacrylate(DMAEMA)and 1-bromohexadecane.The structure of the product was characterized by IR and H’NMR.The reaction conditions were adjusted to optimize the yield.2 Emulsion synthesis(1)Using QAMCA as the functional monomer,methyl methacrylate and butyl acrylate as the monomers,the cationic pure acrylic latex was synthesized by semi continuous seed polymerization.The effects of functional monomers,emulsifiers and other functional auxiliaries on latex particle size and antibacterial properties were systematically studied.Characterization of products are by infrared and nuclear magnetic resonance.The performance of the product was evaluated by DSC and laser particle size analyzer.The results show the mass ratio of cationic emulsifier D to non-ionic emulsifier H is 1:1 accounting for 2%of the total monomer volume.The initiator is made of azo initiator,the total volume is 0.15%.The amount of functional monomers was 5%.The solid content is 50%The E-CA latex with uniform particle size,good freeze-thaw stability,high temperature stability and excellent antibacterial properties was obtained.The emulsion E-CB with QAMCB as monomer was prepared in the same way.The effects of the amount of antibacterial functional monomer,the amount of emulsifier and other additives on the particle size and stability of latex were studied.Characterization of products are by infrared and nuclear magnetic resonance.The performance of the product was evaluated by DSC and laser particle size analyzer.The results show the mass ratio of cationic emulsifier D to non-ionic emulsifier J is 2:1,accounting for 2%of the total monomer volume.The initiator is made of azo initiator,the total volume is 0.2%.The amount of functional monomers was 5%.The solid content is 40%.The E-CB latex with uniform particle size,good freeze-thaw stability,high temperature stability and excellent antibacterial properties was obtained.(3)After comparison of several antibacterial properties,E-CA latex with better antibacterial effect was selected for subsequent coating.3 Coating properties test resultsThe above emulsion E-CA cationic acrylate polymer latex was used to prepare antibacterial coatings.The effects of defoamer,coalescing agents and other auxiliaries on the coating film properties were systematically studied.Based on the performance of coating film,the amount and type of auxilliaries were optimized.The water resistance,alkali resistance,freeze-thaw stability,dry rub resistance and hardness of paint film were evaluated.The result as follows.(1)Using Tego-3062 and Tego-W901 as anti-foaming agents in the weight proportion of 1:4.The dosage of agents is 2%of the emulsion.The coating is smooth without cavities on the surface.(2)The latex paint is configured by mixing the emulsion with high and low glass transition temperature.This kind of Latex paint can produce good film without adding film assistant to reduce the VOC content of latex paint.It can not only ensure the hardness of the paint film,but also do not adhere to it.(3)Test result of latex film:It can pass the alkali resistance text.The hardness can reach 2H.Adhesion can reach more than 0 level.The contrast ratio can reach more than 0.95.Through the test of the stability of freezing and thawing.(4)Through antifungal test.