REAXIS® C708 (Bismuth and Zinc Neodecanoate) is a commonly used blend of bismuth and zinc co-catalyst that is primarily used in polyurethane applications. REAXIS® C708 utilizes neodecanoic acid as the ligand source and enhances compatibility with a wide range of polyurethane formulations. The unique reactivity of REAXIS® C708 is due to the two metal components, each offering different catalytic effects on the overall polyurethane reaction. REAXIS® C708 can, upon request, be provided with different ratios of bismuth and zinc, depending on the desired reactivity. Related catalysts would include REAXIS® C717, a bismuth and zinc catalyst based on an octoate ligand; bismuth neodecanoate products, REAXIS® C716, REAXIS® C3208 and REAXIS® C3209; and the zinc neodecanoate product without bismuth, REAXIS® C616. REAXIS® C708 and its components are present on a wide range of international regulatory lists, including US TSCA, EU REACH and Canadian DSL, which makes it a great choice for international formula development.
For more information, we invite you to read our technical bulletins on Novel Bismuth Complexes for Polyurethane Catalysis and Strategies for Improving Back-End Reactivity of Bismuth Carboxylate Catalysts.
|Bismuth Content (%)
|6.0 - 9.0
|Zinc Content (%)
|6.0 - 9.0
|Color (Gardner Number)
|1.0 - 1.2
|Viscosity (cP @ 20°C)
REAXIS® C708 is primarily used in polyurethane elastomer and rigid foam applications. REAXIS® C708 can also be used in coating and adhesive applications. REAXIS® C708 is used in applications where toxicity concerns need to be mitigated, serving as a potential replacement for commonly used sulfur functional organotins such as REAXIS® C319, REAXIS® C416 and REAXIS® C322. In addition to being used as a polyurethane catalyst, REAXIS® C708 can be used lubricant formulations.
REAXIS® C708 provides a balanced reactivity in select polyurethane reactions. Regarding polyurethane elastomers and foams, this balanced reactivity is achievable due to the presence of both a bismuth and zinc component. Typical of bismuth carboxylates, the bismuth component is similar in reactivity to tin-based catalysts in that it is primarily selective toward the polyol-isocyanate reaction, where this reaction is key to the formation of the urethane groups. The zinc carboxylate component will preferentially catalyze the crosslinking reactions forming biurets and allophanates which leads to physical property enhancements such as hardness build. These zinc- specific reactions typically require additional heat to be effective. These unique reactivity characteristics can be fine-tuned by adjusting the ratios of the bismuth and zinc components, or by using an alternative co-catalyst, such as REAXIS® C717, which is based on an octoate ligand.
REAXIS® C708 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 Bismuth Carboxylates, the primary cause of instability would be hydrolysis.