Study On Sol Modified The External Wall Anti-pollution Latex Coating

The acrylic resin had some advantages such as good flexibility, adhesion,chemical stability and so on. But their disadvantages such as poor anti-water,anti-acid, anti-alkali and anti-pollution performance hindered the furtherdevelopment. As the organic fluoropolymer had low surface energy and hightemperature resistance, it was the best choice for the anti-pollution latex coatingmaterial. But it was expensive and had worse practicability in the market. As akind of cheap and low surface energy materials, silicon sol and titanium solwould substitute partly for fluorine monomer of the fluoride acrylic resin to bethe modified material, it also had seldom influence to the anti-pollution of thefluoride resin and other performance. So it had a high practical value.As a kind of exterior wall coating binders，the fluoride resin latex had goodanti-pollution performance. In this paper, we used the seed-emulsion poly-merization method to synthesize the stable core-shell fluoride microemulsion. Inthis method, we studied the influence like the ratio of soft and hard monomers,fluorine monomer content, emulsifier content, initiating agent dosage, reactiontemperature, pH etc. on the appearance, particles size, hardness, gel rate andcontact angle of the emulsions by controlling variables method, then we got theresult. When the ratio of soft and hard monomers (BA:MMA) was1:1.24, thefluorine monomers content was14.6%, the ratio of composite emulsifiers(OP-10:SDS) was3:1, the reaction temperature was controlled between75and80℃, and the value of pH was between8and9, we could synthesize the polymerwith good anti-pollution performance and the contact angle between the Polymercoating and water was over90%.In this paper, we prepared the stable silica sol and titanium sol by hydrolysismethod at first; then we made two sol modified fluorinated latexes after we usedthese two kinds of sol to modified fluorinated latex separately. The latex microstructure was characterized by FT-IR, transmission electron microscopyand TG. The results showed that the silica sol modified fluorinated latex wasuniform and stable. The latex had obvious core-shell structure and the latexcoating would not be damaged when the temperature was around300℃. Thecontact angle between the polymer coating and water was over100°when theratio of silica sol and fluorine monomer was1:1, it meant that polymer coatingshad low surface energy， so it was a kind of ideal hydrophobic material withlotus effect.We used the fluoride acrylic resin latex which modified by the silica sol asfilm material, added kaolin, titanium dioxide, talcum powder, etc as filler andadded leveling agents, defoamers and thickening agents, etc as auxiliary, weprepared the sol modified the external wall anti-pollution latex coating at theproper process conditions. The surface morphology of the latex coating wascharacterized by SEM, and tested the anti-pollution performance. The resultshowed that the anti-pollution level was zero. Compared with the latex coatingwhich sold in the market, anti-water, hydrophobic and anti-pollution performancehad been improved obviously.