Study On Preparation Of Architectural Latex Coatings And Its Dispersion, Rheology Mechanism

Latex coatings is one of the most important classifications in environment-friendly waterborne coatings. It is a kind of suspension dispersed system which consists of many different chemical materials with different properties. All these components are used to achieve special performance of the coatings. There is complicated interaction between these components. In reality, Formulating a good coatings often depends on experiences, much Edisonian work is needed. The inadequacy on studying the formulating mechanism often bring us some problems: on the one hand, It's hardly for us to make a well-balanced formulation, on the other hand, we can't provide some important questions for research institute related to coating industry and promote the technology to go forward. Therefore, Studying the formulating mechanism and the interaction between components are of great significance.On studying the dispersion of pigments in waterborne system, It showed that PH of the system have significant effect on the dispersion of pigments, Its action is achieved by changing the Zeta-potential on the pigment particle. Electrolytes would shield the electrostatic repulsion and make the particles aggregate. Polymeric dispersants would increase the Zeta-potential on the particles, at the same time, could improve the stability of the pigment dispersion by steric stability, Electrolytes couldn't influence this system. In evaluating the performance of dispersants, the turbidity of supernant in dispersion could be used as a quick and effective standard. In waterborne system, the adsorption of polymeric dispersants on the surface of pigment particles is achieved by hydrophobical interaction.On studying rheology properties of latex coatings, It showed that the thickening of traditional water soluble polymer is achieve through thickening the continuous water phase, this would lead to difficulties to level. Results of viscoelastic experiments showed that both thickening water phase and association between particles is pertinent to hydrophobically modified water soluble polymer, this unique property have leveling as well as antisagging advantages. HEUR thickener can adjust the rheology at both low-shear rate and high-shear rate, but the surfactants in the...