Alkyds and Polyesters
Pages: 7 Published: Jan 2012
ALKYDS ARE SYNTHETIC POLYMERIC MATERIALS that have been used in the coating industry since the 1930s. Today, they continue to be workhorse polymers for the paint, coating, and printing ink industries. Alkyds and chemically modified alkyd resins are the condensation products of poly-basic acids and polyhydric alcohols. They are used in liquid organic coatings for the architectural, industrial, automotive, and industrial maintenance markets. Alkyds are also known as oil-modified polyesters because of the presence of vegetable or marine oils or other fatty acids. These oils are coreacted into the polyester backbone. The type of oil or fatty acid present in the alkyd contributes to its oxidative cure characteristics. In a chemical sense, alkyds are polyesters that are formulated with drying or nondrying oils. In contrast, polyesters are oil free. Alkyds are often modified with other polymeric materials for particular property attainment. Three major classifications of alkyds are those designed for conventional solids, higher solids, and water-borne coatings. Because there are a large variety of commercially available intermediates and chemical modifiers, i.e., monomers, for the preparation of alkyds, they continue to be a very versatile type of polymers for coatings and printing inks. Most alkyds are film-forming polymers with a relatively low glass transition temperature (
Paper ID: MNL12187M
ASTM International is a member of CrossRef.