Raw materials for water-borne coating formulations

Generally coating compositions consist of quite a few different raw materials. Emulsion polymers as binder as well as pigments and extenders are the most crucial and basic constituents. They usually make up for the major part of a coating. However, they cannot be formulated into a paint that fulfils the required application properties. Additives have to be employed to adjust flow behaviour, ensure a proper dispersing of the pigments, improve film formation, control foam formation, prevent microbiological attack etc. (Bielemann, 2000). 

C Water E Additves C Filter+Extender C Pigment Polymer emulsion (50% solids content) 

The binder holds the coating together and makes it adhere to the substrate. It provides many of the performance features needed for specific coating applications, for example, toughness and elasticity to resist mechanical impact, such as scratching, abrasion or yield stress, stability against chemicals, water resistance etc. In the market different types of emulsion polymers are established (Padget, 1994)  

There are three main classes of thickeners, which are commonly used CeUulosics (modified natural products, usually hydroxy-ethyl cellulose - HEC), HASE (hydrophobic-ally modified alkali-sweUable emulsions) and HEUR (hydrophobically modified ethylene oxide urethanes). 

CeUulosics are relatively high molecular weight water-soluble polymers, which thicken by raising the viscosity of the water phase of the coating. 

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