PRACTICAL GUIDE TO ASSOCIATIVE THICKENERS: STRUCTURE, THICKENING MECHANISMS AND THEIR EFFECT ON COATINGS PROPERTIES

摘要

Associative thickeners have become in recent years an important group of rheological additives used in various coatings formulations because they impart improved application properties to the coating system, in particular flow and leveling. Associative thickeners for water based systems are ionic or nonionic water-based copolymers containing hydrophobic groups. Commercial associative thickeners include polyether polyurethanes, polyether polyols, hydrophobically modified alkali swellable polymers and hydrophobically modified cellulosic ethers. The chemical structure of the hydrophilic and hydrophobic parts of the polymer determines the ability of these thickeners to associate into micelles in water. Associative thickeners are also capable of interacting with other ingredients in the formulation to form a three-dimensional network structure. This paper reviews the increasing number of theoretical studies and examines the effects of thickening mechanisms on the application properties of the coating such as sag resistance, leveling, and film thickness. It provides a comparison of the effects of commercial thickeners on the properties of architectural coatings and may serve as a guide to the coating formulator.