Foam flowability is very important to properly fill the mold, especially with large and complicated profiles. On the other hand, good curing is essential to perform short demolding times and to avoid fingerprinting when the pad is taken out of the mold. To combine excellent in-mold flowability and fast curing, delayed-action catalysts were developed. When starting reactivity is too high, delayed-action blow catalysts should be employed; on the other hand, delayed-action gellation catalysts are used to delay the viscosity build-up of the reacting mixture allowing to flow easily in the mould cavity. The process to manufacture a delayed-action catalyst involves reacting a specified tertiary amine with a carboxylic acid. The resulting compound is composed of a salt and an excess of the starting amine. The salt has limited or no catalytic activity and when this blend is used in a foam formulation, the free amine launches the reaction, but when the reactions have progressed, with heat generation, the salt dissociates to yield back the amine and the acid. At this time the catalyst is de-blocked and has recovered the original activity. The released organic acid reacts with isocyanate-forming carbon dioxide and carbon monoxide, supplying an auxiliary source of blowing agent, resulting in less dense with more open cell foams. Normally, carboxylic acids such as formic and 2-ethylhexanoic acids are used as blocking agents. The unblocking temperature depends on the acid used. Strong acids require higher temperatures than the weak ones. In commercial applications the unblock temperature is located between 30oC and 60oC. There is some corrosion linked to the use of formic acid and the foams produced tend to be very closed and are therefore difficult to open