The associative polyurethane thickener is an associative structure that is damaged under the action of shearing force and the viscosity is reduced. When the shearing force disappears, the viscosity can be restored, which can prevent sagging in the construction process. And its viscosity recovery has a certain hysteresis, which is conducive to the leveling of the coating film. The relative molecular mass (thousands to tens of thousands) of polyurethane thickeners is much lower than the relative molecular mass of the first two types of thickeners (hundreds of thousands to millions) and does not promote splashing. Polyurethane thickeners have both hydrophilic and hydrophobic groups on the molecule. The hydrophobic groups have a strong affinity with the substrate of the coating film, which can enhance the water resistance of the coating film. Since the latex particles participate in the association, flocculation will not occur, so the coating film can be smooth and have high gloss.
Many properties of associative polyurethane thickeners are better than other thickeners, but due to its unique micellar thickening mechanism, those components that affect micelles in coating formulations will inevitably have an impact on thickening properties. When using such thickeners, the influence of various factors on the thickening properties should be fully considered, and the emulsions, defoamers, dispersants, film-forming aids, etc. used in coatings should not be easily replaced.