INTRODUCTION
Alkyd resins have been introduced in the 1930s as binders for paints. Their compatibility with many polymers and
the extremely wide formulating latitude made them suitable for the production of a very broad range of coating
materials. This includes do-it-yourself paints and varnishes for wood and metal, road marking paints, anticorrosive
paints, nitrocellulose lacquers, two-component isocyanate curing coatings, acid curing coatings, stoving enamels,
etc. Except for phthalic anhydride, being of petrochemical origin, the other raw materials used in the synthesis of the
alkyds are from biologically renewable sources. This, combined with their biological degradability, makes them
very interesting binders from an ecological point of view. Solvents which are used to reduce and adjust the paint
viscosity are the only concern with respect to the ecological aspects of the alkyds paints. In recent years, however,
we witness quite an activity in designing alkyd emulsions and high solids alkyds which can serve as binders for
environmentally friendly coatings.[1]
Alkyd resins are the reaction products of polybasic acids, polyhydric alcohols and monobasic fatty acids or oils. It is
a chemical combination between oil or oil-derived fatty acids and polyester polymer, thus enhancing the mechanical
properties, drying speed durability of these oleoresinous vehicles formed over and above those compared with the
oil themselves. These resins, today comprise about half of all resins used in the surface coating industry.
In spite of a large number of other synthetic resins being available for use in paint formulations, the alkyd resins
surpassed all of them in versatility and low cost together with a broad spectrum of performance properties.
It is possible to produce alkyds with greatly improved resistance to hydrolysis by the use of acid containing
sterically hindered carboxyl groups , such as the “ versatic acids ” . These are a mixture of heavily branched
aliphatic acids with 9 to 11 carbon atoms and with most ( > 93% ) of carboxylic groups attached to a quaternary
carbonation.