REAXIS® C218 (Dibutyltin Dilaurate), commonly abbreviated to DBTDL, is one the most commonly used specialty metal-based catalysts for polyurethanes and silicone condensation reactions. With a long history of usage in a wide range of formulations, REAXIS® C218 is a good benchmark catalyst when starting development work on new formulations. Typically supplied in a neat liquid form, it can be supplied in a wide range of diluents including amines, silanes, and plasticizers.
|Tin Content (%)||18.0 Min|
|Density (g/ml)||1.03 - 1.07|
|Refractive Index (nD @20°C)||1.469 - 1.476|
|Acid Number (mgKOH/g)||165 - 180|
|Color (Gardner Number)||3 Max|
REAXIS® C218 is a work-horse catalyst used primarily in polyurethane and silicone chemistries. It also can be used as an esterification and transesterification catalyst. DBTDL can be used in a wide range of applications within the above-mentioned chemistries, including: coatings, adhesives and sealants, elastomers, foams and plastics. Given the lubricious nature of tin metal, REAXIS® C218 is also used in select lubricant formulations.
Reactivity-wise, REAXIS® C218 provides a balanced reactivity profile, front-end to back-end. In regard to polyurethanes, a good balanced cure is achievable given the presence of both a low tin metal content and large ligand. Thus, a balanced front-end/pot-life and back-end/final cure reactivity profile can be achieved in, as an example, 2K polyurethane coatings. REAXIS® C218 is a carboxylate specialty metal-based catalyst that is built with a biobased ligand and thus color formation is possible especially when heat is added or generated. Typical of the organotin carboxylate family of catalysts, REAXIS® C218 will catalyze most polyurethane reactions; it is primarily selective toward the polyol-isocyanate and water-isocyanate reactions. REAXIS® C218 is hydrolytically stable within typical formulation moisture levels, but this stability will break down with increasing moisture content.
REAXIS® C218 should be stored in the original packaging at moderate temperatures and kept from freezing. The container should be closed tightly after each use to maximize shelf life. Characteristic of most Sn (IV) organotins, the primary cause of instability would be hydrolysis. Hydrolysis results in the formation of tin oxide insolubles leading to deactivation of REAXIS® C218.