Preparation Of The Waterborne Stone-like Coatings With The Hectorite As Protective Glue And Research Of Its Stability

In this paper, the waterborne stone-like coatings is prepared by the gelation reactionbetween the hydroxy of HEC and the metal cation of hectorite. It’s mainly composed bythree parts, which are the dispersion phase(the water-based latex paint),the dispersionmedium(the water solution containing the protective glue and the viscositydepressant)and the varnish, accordinigly. By means of studying the main components ofthe three above, we discussed the influence on the form of the colourful granules,bleeding performance and stability of the emulsion, which are caused by HEC, thehigh concentrations of protective glue solution, additives, the viscosity depressant andtechnological parameter, respectively. Stormer viscosity, rorational viscosimeter havebeen adopted in the test of the viscosity of the dispersion phase and the waterbornestone-like coatings. Also, the dispersion medium is tested by Uv-vis spectrophotometer,Zeta-potential-analyzer and FT-IR. The results indicate that：The dispersion phase is prepared with25～35%of elastic emulsion TRC-4369,1%of HEC,4%of the high concentrations of protective glue solution,3%of pigs andfillers(titanium dioxide+kaolin),0.3%of bactericide and other additives. Also used colorpaste of “Shi Ming”to the dispersion phase color. The absorbance in the visible region ofthe dispersion medium is smallest thorugh stirring to form the colorful granules. Atpresent, the colorful granules has the best resistance performance of the bleeding.Zeta potential presents that the greater the absolute value, the better the viscositystability of water-based multicolor coating as well as the fewer thickening range.. FT-IRmeasurements shows that the phosphate disperses the hectorite, then they combine withhydrogen bond. The optimum stability of water-based multicolor coating is under suchconditions,which the concentration of hectorite is2%; the concentration of viscositydepressant is0.3%compounded by sodium pyrophosphate, sodium tripolyphosphate aswell as sodium hexametaphosphate in same proportions.The silicone-acrylate emulsion with excellent dirt resistance should be chosen asemulsion of varnish,whose viscosity should be controlled within the range of75～80KU,and dosage is about5%of the total dispersion phase and dispersion medium quality.Above all, both of which are on the basic that the colorful granules does not sink.The optimum manufacturing technology on the waterborne stone-like coatings isthat paddle mixer blade inclined45°, and the mixing time controls within5min; also,the temperature of the dispersion medium is controlled under30℃with the pH valueunder9. It is feasible to controle the size of the colorful granules by changing the stirringspeed. And mass ratio between the dispersion phase and the dispersion medium could befrom1.0:1to1.5:1, by controlling the size of colorful granules.In the process of mixing, the addition of defoaming could guarantee a good state ofdefoaming, also bactericide could make the system avoid “corruption”. As for thequantity of defoaming agent and bactericide,0.1%of the dispersion medium quality isOK.Performance testing results show that the indicators of the waterborne stone-likecoatings reached the standard of all requirements. The decoration effects will be changedwith different colours, different size colorful granules collocations, as well as seam’sdesign, ect.