Chemical auxiliaries are chemical additives used in a certain industry, and there are many kinds of them, including metal processing auxiliaries, plastic auxiliaries, paper auxiliaries, construction auxiliaries, water treatment auxiliaries, coating auxiliaries, leather auxiliaries, auxiliaries for the electronics industry, textile printing and dyeing auxiliaries, wood auxiliaries, etc.
Rheology modifiers used in water-based coatings are the same as solvent-based coatings. They need to have good thickening effects and rheological properties, which not only make the coating have high viscosity at low shear rates, but also prevent precipitation , Anti-sagging and anti-permeability functions, and can make the viscosity of the coating drop with the increase of shear rate, and gradually recover as the shear disappears, and can adjust the speed of viscosity recovery to promote leveling and prevent sagging. The balance of the coating can improve the operating performance during coating construction and increase the fullness of the coating film.
The commonly used rheology modifiers mainly include cellulose ethers, alkali swellable acrylate copolymers, hydrophobically modified cellulose ethers, hydrophobically modified alkali swellable acrylate copolymers and hydrophobically modified polyurethanes. Among them, the hydrophobically modified polymers are all associative rheological thickeners, which can not only give the system a certain thickening effect, eaa dispersion but also improve the leveling and splash resistance of the system.
Cellulose ether thickeners have very good anti-settling and anti-sagging effects, but can only provide limited shear thinning fluidity and thixotropy, so the leveling and splash resistance are not good. Alkali swellable acrylate copolymer has better shear thinning fluidity and good thixotropy than cellulose ether. It has good anti-precipitation, anti-water separation and anti-sagging effects, and also has a certain leveling effect. . These two types of rheology modifiers are non-associative, mainly to thicken the water phase in the system, and have no effect or small effect on other components, so they have a small contribution to the leveling effect and the anti-sagging effect. Great contribution.
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