Diamines are the most common curatives for TDI systems, where diols and polyols are preferred with MDI systems. Hybrids of amine curatives and polyols are also employed with both TDI and MDI systems.
MOCA -4,4'-Methylene-bis(ortho-chloroaniline)
MOCA is a unique curative and chain extender for isocyanate pre-polymers, and epoxy resins, characterized by extended gel times at high temperatures. Polyurea semi-rigid foams and solid hot cast elastomers produced using MOCA exhibit durability, resiliency, excellent abrasion resistance, tensile, cut, tear, compressive strength properties, and impact strength, etc.
MCDEA -Methylene bis(2,6-diethyl-3-chloroaniline)
MCDEA is a solid, high performance, hindered aromatic diamine curative and chain extender for isocyanate and pre-polymers. It affords polyureas with superior mechanical and dynamic properties and extended gel times. MCDEA provides excellent mechanical properties with low hysteresis (heat build-up), excellent temperature resistance up to 150ºC (302ºF), good resiliency, abrasion, wear and tear resistance, and processing advantages. MCDEA is preferably used with TDI based urethane prepolymers.
DETDA -3,5-diethytoluene-2,4-diamine and 3,5-diethytoluene-2,6-diamine
DETDA is a liquid mixture of 3,5-diethytoluene-2,4-diamine and 3,5-diethytoluene-2,6-diamine used as a specialty curative and chain extender for diisocyanate pre-polymers, creating polyureas with excellent mechanical and dynamic properties. It is also a curing agent for epoxy resins.
DETDA provides excellent mechanical properties with low heat build-up under high compression loads, good resiliency, abrasion, wear and tear resistance, and processing advantages.
HQEE -Hydroquinone bis (2-hydroxyethyl) Ether
HQEE is a symmetrical aromatic diol chain extender for polyurethanes. The polyurethane cured by HQEE exhibits higher melting temperatures vs. BDO. Therefore, HQEE-based elastomers show greater elevated temperature performance vs. comparable BDO systems. HQEE can improve tensile, hardness and resilience properties in MDI-polyurethane elastomers. HQEE/MDI PUR elastomer series parallels MOCA/TDI.
BDO -1,4-Butanediol
BDO is a stable, hygroscopic, clear, colorless liquid with a freezing point of 19-20ºC and a boiling point of 230°C. It is used extensively as a chain extender (curative) in production of polyurethane elastomers by reaction with diisocyanates and in the manufacturing of polyester polyols by reaction with dibasic acids.