Alkyd

An alkyd is a polyester resin modified by the addition of fatty acids and other components.[1] Alkyds are derived from polyols and organic acids including dicarboxylic acids or carboxylic acid anhydride and triglyceride oils. The term alkyd is a modification of the original name "alcid", reflecting the fact that they are derived from alcohol and organic acids.[2] The inclusion of a fatty acid confers a tendency to form flexible coatings. Alkyds are used in paints, varnishes and in moulds for casting. They are the dominant resin or binder in most commercial oil-based coatings. Approximately 200,000 tons of alkyd resins are produced each year.[3] The original alkyds were compounds of glycerol and phthalic acid sold under the name Glyptal.[4] These were sold as substitutes for the darker-colored copal resins, thus creating alkyd varnishes that were much paler in colour. From these, the alkyds that are known today were developed.

Structure of an idealized alkyd resin derived from glycerol and phthalic anhydride
  1. ^ "Alkyd Resins", Polymer Syntheses, Organic Chemistry, vol. 29, Elsevier, 1977, pp. 140–170, doi:10.1016/b978-0-12-618502-7.50010-6, ISBN 978-0-12-618502-7, retrieved 2021-05-14
  2. ^ Elliott, W. T. (1993), "Alkyd Resins", Surface Coatings: Volume 1 Raw Materials and Their Usage, Dordrecht: Springer Netherlands, pp. 76–109, doi:10.1007/978-94-011-1220-8_5, ISBN 978-94-011-1220-8, retrieved 2021-05-14
  3. ^ Frank N. Jones. "Alkyd Resins". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_409. ISBN 978-3527306732.. Published online: 15 January 2003.
  4. ^ "Properties of Alkyd Resins". polymerdatabase.com. Retrieved 2021-05-14.