The percent NCO is used to establish unit ratios for stoichiometric reactions with co-reactants.

1.1 This test method covers the determination of the isocyanate group (NCO) content of a urethane intermediate or prepolymer.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.