There are a variety of catalysts used for polyurethane rigid foam reactions and gel reactions, some examples of which are listed below: Foaming reaction catalysts: Organotin compounds, such as ethylenetrimethylene tin (T-9) and ethylenetriethyltin (T-12). Organotin-cobalt composite catalysts, such as ethylenetrimethyltin-cobalt (T-9/Co). Organotin-acid catalysts, such as ethylenetrimethyltin-benzoic acid (T-9/BzOH). Phosphate catalysts such as triphenylphosphine (TPP)...