TIB KAT 321

TIB KAT 321 – Dibutyltin bis(2-ethylhexyl mercaptoacetate) for PU adhesives, elastomers & foams

TIB KAT 321 (dibutyltin bis-(2-ethylhexyl mercaptoacetate), dibutyltin mercaptide) is a butyl-based dialkylated Sn(IV) organotin catalyst with a thiol-functionalized ligand.

This ligand provides:

• more controlled reactivity (upfront delay)
• improved hydrolytic stability
• characteristic organotin performance in PU curing

This makes TIB KAT 321 more reactive and easier to control than classic metal carboxylates such as TIB KAT 218, TIB KAT 216 or TIB KAT 300.

Areas of application

TIB KAT 321 is mainly used in polyurethane applications, especially where targeted, delayed reaction control is required:

• PU adhesives
• Elastomers
• PU foams

For coatings, TIB KAT 321 is particularly suitable in oven/bake cure systems, less so in room temperature curing systems.

Selective reaction behavior

• Preferred catalysis of the isocyanate-polyol reaction
• Less influence on the water reaction
• Limited use in water-based formulations

Inactive in silicone and ester applications

Due to the sulfur-containing ligand, the catalyst acts as a blocker in these applications. → Thermal deblocking is necessary to start the back-end reaction.