ASTM D2572-97(2010)

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

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 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.
Significance and Use:

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