To determine how much curative to be used per 100 parts of any Air Products prepolymer, the following equation should be used:

The % NCO is marked on each drum.

Example:
An 80 Shore A durometer formulation is desired. Versathane A-8 prepolymer, containing 3.1% NCO, is to be used with MBOCA curative. The equivalent weight of MBOCA is 133. How much curative is required at 95% stoichiometry?

= 9.33 parts MBOCA curative per 100 parts prepolymer