Delayed action catalysts were developed some years ago in the face of the increasing
complexity and size of the molds as well as the need to shorten demolding time to achieve
higher productivity. Typical delayed action catalysts are tertiary amines blocked with an
organic acid, and can be thermally activated. Organic acids and tertiary amines react in a
reversible reaction to form ammonium salts, which exhibit little or no catalytic activity
when compared to the initial amine. During the exothermic urethane formation, the amine
catalyst is dissociated gradually and there is a delay in viscosity buildup, providing a better
flowability of the system into the mold. Typical examples of systems with catalytic
delayed action are tertiary amines such as DABCO and BDMAEE that react with organic
carboxylic acids such as formic or cyanoacetic acid.[9] Among the disadvantages of these
systems is the strong corrosive action of the organic carboxylates that causes a faster
deterioration of foaming machine and storage vessels due to the release of the carboxylic
acid. The use of saturated dicarboxylic acids such as adipic and sebacic acids has been
proposed as a less corrosive alternative