A catalyst is a chemical which makes a chemical reaction go faster, but is not itself used up in the reaction. In paints catalyst speed up the formation of polymers from the resins. Cobalt octoate is used in gloss paints to accelerate the polymerization of alkyd resin thus acts as paint drier and also known as oxidation catalyst.
Cobalt octoate is the most reactive and most commonly used paint drier. Cobalt octoate catalyses the oxygen uptake and accelerates peroxide formation causing a surface film to form rapidly and hence known as oxidation catalyst. It basically a metal caroxylate used to accelerate the drying process like linseed oil.
Cobalt octoate promotes polymerization of media , hardens the paint film, improves film gloss free from frosting tendency and increases water resistance. This paint drier is capable of performing individually giving reasonable properties to the paint film. As an oxidation catalyst cobalt octoate accelerates the catalytic action of methyl ethyl ketone (M.E.K) Peroxide to polymerize unsaturated polyester resin.
As a paint drier it is usually added at 0.05 to 0.4% based on solid content ratio and is compatible with all surfaces coating media. It does not allow atmospheric humidity too penetrate the paintfilm.