Bismuth neodecanoate
The leading tin-free polyurethane catalyst, offering strong gel activity with a better toxicity profile than organotins.
Bismuth neodecanoate is a bismuth(III) salt of neodecanoic acid, a branched C10 carboxylic acid. It is supplied as a liquid, often diluted in neodecanoic acid or solvent, with formula Bi(C₁₀H₁₉O₂)₃.
It catalyzes the isocyanate–hydroxyl reaction in polyurethane coatings, elastomers, adhesives, sealants and cast systems, as a direct replacement for tin catalysts where regulation or customer specifications require tin-free products.
Bismuth carboxylates are selective toward the NCO–OH reaction over the NCO–water reaction, helping reduce CO₂ gassing. They are sensitive to hydrolysis, so in water-containing or humid B-sides activity can drop over storage; formulators use stabilized grades or add catalyst shortly before use.
Follow the SDS: carboxylic acid carriers can irritate skin and eyes. Bismuth compounds are generally considered lower in toxicity than organotins.
Often close, but activity profiles differ, so dosage and pot life usually need adjusting and testing.
Water hydrolyzes bismuth carboxylates, reducing activity in wet or humid systems over time.
