Attapulgite pre-gel for rheology control of water-based industrial coatings

摘要

Anti-settling of waterborne industrial coatings has become a hot topic recently. Rheology modifiers are generally used for anti-settling. However, they may also lead to some detraction of properties, such as water-resistance, levelling, spattering, syneresis, bacteria and enzyme resistance etc. Attapulgite clay, in such formulations, works more than as a thixotrope. It can give excellent pigment and filler suspension without the issues mentioned above. This article explores how to make an optimised pre-gel formulation of Attagel 50 for waterborne industrial coatings. The shear speed of 4000rpm for 30min was found to give the best results. In the absence of a dispersant, 12.5% Attagel 50 was found to be the optimum solids content in the pre-gel formulation. In the presence of 3.2% of a polyacrylic acid dispersant (Dispex AA 4040), 25% Attagel 50 is the best dosage for the pre-gel formulation.