Paints and Coatings

Abstract

Coatings syn. coating solutions are liquid, liquefiable, or mastic compositions which harden to a film to decorate or protect a variety of materials against corrosion or oxidation. Coatings, including paints (pigmented coatings), varnishes, lacquers, enamels, stains, polishes, fillers, and shellacs have one or more of the following components:

• Binders that hold the ingredients of the coating together and form tough, solid, elastic films on drying. Binders include natural or synthetic resins (e.g., rosin and balsam) which harden on evaporation of a solvent; drying oils (e.g., linseed, tung, soybean, fish, castor, perilla), organic liquids that polymerize to hard films through air oxidation; or other film-forming agents. Hardening is accelerated by the addition of paint driers or varnish driers metals, and other compounds that speed oxidation, evaporation, or polymerization. Heat or other radiation sources may increase the rate of hardening.

• Pigments and dyes, including titanium dioxide, lead chromate, and aluminium flakes (which are used in aluminium paint syn. aluminium liquid to give a highly reflective metallic finish).

• Dispersants, preservatives, flame retardants, fillers, and other additives.

• Solvents or paint thinners which carry the binder, pigments, and additives and facilitate application. These evaporate on application and are also known as reducing compounds (compounds used to reduce viscosity).