Preparation And Properties Of Self-matting Waterbrone Acrylic Resin

The matting coating,which has a broad application prospect in the fields of furniture,electrical appliance shells,interior and exterior walls,leather and print varnishing,can not only hide the fine scratches to improve the decorative effect,but also avoid glare and reduce people’s visual fatigue.Water-based matting varnish for water-based thick coating or water-based matting oil for paper printing generally requires both matting and transmittance performance,but there is a contradiction between them,usually improve its matting performance at the expense of the transmittance.The current matting coating is mainly achieved by adding matting agent,causing some problems,such as incompatibility between the matting agent and film-forming substances,easy chalking and peeling of the coating,poor tactile feel of the coating and color distortion.In this work,two kinds of self-matting acrylate copolymer latexes were prepared by emulsion polymerization using vinyl monomers grafted with organosiloxane groups or super-hydrophobic alkyl groups through molecular design,and the self-matting films formed from latexes directly without adding additional matting agent were achieved by constructing a rough surface through migration of different groups with low surface tension.The main work is as follows:(1)Self-matting acrylate copolymer latex was prepared by emulsion copolymerization using butyl acrylate,methyl methacrylate,acrylic acid and styrene as main monomers,and3-methacryloyloxy-propyltris-trimethylsiloxy-silane(MPTS)as functional monomer.During the film forming process,the organosiloxane groups with low surface tension on the copolymer chain would migrate to the film surface within a certain range,to induce uneven contraction owing to the difference of surface tension,fabricating a rough surface to realize the film self-matting.The effect of functional monomer addition amount on the film glossiness was investigated,and the morphology and composition of films were characterized by SEM,AFM and XPS.Results showed that when the addition amount of MPTS increased from 0% to 15%,the film roughness increased,causing the static water contact angle value increased from 75.8° to 105.2°,the glossiness decreased from 95.3 GU to 31.5 GU sharply,but the transmittance only decreased from 98.9% to 87.8%,much better than that of the film with externally added inorganic nano-silica matting agent(≤ 70%).XPS results proved that the organosiloxane segments enriched on the film surface because the silicon element content of film prepared by 10% addition amount of MPTS is as high as 10.9%,which is much larger than the theoretical silicon element content of 1.21%.Due to the organosiloxane groups would offer self-layering properties,films still had excellent adhesion,and flexibility and yellowing resistance of the film at high temperatures are also good.(2)Self-matting acrylate copolymer latex was prepared by emulsion copolymerization using beheneth-25 methacrylate(BEM)with long-chain alkyl groups and polyoxyethylene ether groups as functional monomer.The hydrophilic polyether segment in BEM ensures the successful implementation of emulsion polymerization,and the super-hydrophobic long-chain alkyl groups spontaneously migrate to the film surface during the film formation process,prompting uneven shrinkage to form a rough surface to realize the self-matting.The effects of emulsifier type and addition amount,and the method of buffer addition on the stability of emulsion polymerization were investigated.The matting performance of films prepared by different addition amount of BEM was examined,and the film morphology was characterized by SEM and AFM.Results showed that when the addition amount of BEM was lower than 15%,the emulsion polymerization with a low coagulation percentage(<0.5%)could be carried out smoothly.With increasing the addition amount of BEM from 0% to 20%,the glossiness decreased from 91.6GU to 35.4 GU due to the film roughness increased,while the transmittance decreased from 99.1% to 89.7%.The films still had excellent adhesion because the super-hydrophobic long-chain alkyl groups on copolymer chains would offer self-layering property,and flexibility and yellowing resistance of films at high temperatures are good too.