REAXIS® C318 (Dioctyltin Dineodecanoate) is an octyl-based organotin used most commonly as a catalyst for polyurethane and silicone condensation reactions. The presence of the neodecanoate ligand and the percentage of active tin metal make Dioctyltin Dineodecanoate a suitable candidate across a broad spectrum of formulations. The butyl analogue of REAXIS® C318 would be REAXIS® C221 (Dibutyltin Dineodecanoate) and the methyl analogue is REAXIS® C325 (Dimethyltin Dineodecanoate). Alternative octyl derivatives would include REAXIS® C228 (Dioctyltin Diacetate), REAXIS® C216 (Dioctyltin Dilaurate) and REAXIS® C314 (Dioctyltin bis-(2-ethylhexyl Maleate). Inorganic tin alternatives would include REAXIS® C125 (Stannous Neodecanoate) and REAXIS® C129 (Stannous Octoate). All the above-mentioned products are neat liquids with varying metal content and ligand makeup.
For more information, we invite you to read our technical bulletins on Iron Catalysts for Urethane Chemistries and Strategies for Improving Back-End Reactivity of Bismuth Carboxylate Catalysts.
|Tin Content (%)
|15.7 - 17.5
|1.01 - 1.05
|Viscosity (cP @ 20°C)
|150 - 250
|Color (Gardner Number)
REAXIS® C318 and its alternatives can be used as a homogenous tin catalyst in a wide spectrum of polyurethane and silicone applications including adhesives and sealants, elastomers and plastics, and coatings. Silicone-based applications include: acetoxy-, ethoxy- and oxime-based Room Temperature Vulcanizing (RTV) adhesives and sealants, polyethylene crosslinked silanes (PEX), and select silane modified polymers (SMPs). Dioctyltin Dineodecanoate and its analogues are preferentially used in formulations with oxime functionality. In regard to polyurethane applications, REAXIS® C318 can be used for most related applications including coatings, adhesives and sealants, elastomers, and foams. REAXIS® C318 is used in formulations utilizing either aliphatic or aromatic isocyanates and a wide range of polyether and polyester-based polyols. REAXIS® C318 is present on most global chemical inventory lists, making it a great choice where your final product will need the approval of multiple regulatory bodies.
Due to the larger alkyl group and steric effects and lower active tin metal content, REAXIS® C318 is expected to be slower in reactivity compared to its butyl and methyl analogues, REAXIS® C221 and REAXIS® C325, respectively.. Reactivity difference is evidenced both in polyurethane and silicone chemistries in general, across all applications. In regard to silicone reactions, REAXIS® C318, like all tin-based catalysts, will catalyze the silanol/silane condensation reaction,acting as both a polymerization and crosslinking catalyst. As a polyurethane catalyst, REAXIS® C318, will preferentially catalyze the urethane reaction and to a lesser extent the water reaction, acting as a polymerization/gelation catalyst. Compared to other octyltins, REAXIS® C318 is in the middle of the pack in regard to active tin metal content and reactivity, which makes it a good starting point for new formulations.
REAXIS® C318 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® C318.