Urethane alkyd resin

A process for synthesizing siliconized-urethane alkyd resin composition comprising the steps of:

• a) reacting one or more polyhydric alcohols with one or more polybasic acids/acid anhydrides, hydroxycarboxylic acids and monofunctional carboxylic acids along with oils/fatty acids in presence of a catalyst and reflux solvent at a reaction temperature of 170-250° C. till acid number of 6-10 mg KOH/gm is achieved, to produce the base alkyd resin component with OH number in the range of 50-150 mg KOH/gm;
• b) heating said base alkyd component with organosilane component to a temperature range of 130-220° C. till an acid number of 1-5 mg/KOH is achieved, followed by distilling out methanol/water reaction condensates generated during siliconization reaction and diluting to 40-90% non-volatiles with a solvent, wherein the solvent is selected from the group of isomers of xylene and mineral turpentine oil to deliver a siliconized alkyd;
• and
• c) reacting said siliconized alkyd through its free hydroxyls with any one of aliphatic, cycloaliphatic and aromatic polyisocyanates or their derivatives at a temperature of 50-130° C., in presence of a catalyst providing siliconized-urethane alkyds having nonvolatile content of 40-90%, wherein the process is carried out in situ in a single pot.