An alkyd is a polyester resin modified by the addition of fatty acids and other components. 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. 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. The original alkyds were compounds of glycerol and phthalic acid sold under the name Glyptal. 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.
Alkyd in the context of Drying oil
A drying oil is an oil that hardens to a tough, solid film after a period of exposure to air, at room temperature. The oil hardens through a chemical reaction in which the components crosslink (and hence polymerize) by the action of oxygen (not through the evaporation of water or other solvents). Drying oils are a key component of oil paint and some varnishes. Some commonly used drying oils include linseed oil, tung oil, poppy seed oil, perilla oil, castor oil and walnut oil. The use of natural drying oils has declined over the past several decades, as they have been replaced by alkyd resins and other binders.
Since oxidation is the key to curing in these oils, those that are susceptible to chemical drying are often unsuitable for cooking, and are also highly susceptible to becoming rancid through autoxidation, the process by which fatty foods develop off-flavors. Rags, cloth, and paper saturated with drying oils may spontaneously combust (ignite) after a few hours as heat is released during the oxidation process.
View the full Wikipedia page for Drying oilAlkyd in the context of Linseed oil
Linseed oil, also known as flaxseed oil or flax oil (in its edible form), is a colorless to yellowish oil obtained from the dried, ripened seeds of the flax plant (Linum usitatissimum). The oil is obtained by pressing, sometimes followed by solvent extraction.
Owing to its polymer-forming properties, linseed oil is often blended with combinations of other oils, resins, or solvents as an impregnator, drying oil finish, or varnish in wood finishing; as a pigment binder in oil paints; as a plasticizer and hardener in putty; and in the manufacture of linoleum. Linseed oil use has declined since the 1950s with increased availability of synthetic alkyd resins, which function similarly, are petroleum-based, and resist yellowing.
View the full Wikipedia page for Linseed oilAlkyd in the context of Melamine resin
Melamine resin or melamine formaldehyde (also shortened to melamine) is a resin with melamine rings terminated with multiple hydroxyl groups derived from formaldehyde. This thermosetting plastic material is made from melamine and formaldehyde. In its butylated form, it is dissolved in n-butanol and xylene. It is then used to cross-link with alkyd, epoxy, acrylic, and polyester resins, used in surface coatings. There are many types, varying from very slow to very fast curing.
View the full Wikipedia page for Melamine resin