ISO 14898:1999

Plastics — Aromatic isocyanates for use in the production of polyurethane — Determination of acidity

This International Standard specifies methods for the measurement of the acidity of aromatic isocyanates and

prepolymers used as polyurethane raw materials. Method A is a straightforward titration without a blank and is

primarily applicable to products derived from crude or modified methylene-bis-(4-phenylisocyanate), polymethylene

polyphenylisocyanates and toluene diisocyanate having moderate to high (> 100 mg/g ) levels of acidity. Method B is

applicable to refined, crude or modified isocyanates derived from methylene-bis-(4-phenylisocyanate), polymethylene

polyphenylisocyanate and toluene diisocyanate having low (< 100 mg/g ) levels of acidity, and a blank is employed.

These methods can also be used for isomeric mixtures of toluene diisocyanate, methylene-bis-(4-phenylisocyanate)

and polymethylene polyphenylisocyanate. Other aromatic isocyanates may be analysed by this method if

precautions are taken to verify suitability.

Edition	1999
Published Date	1999
Published By	International Standardization Organisation
Page Count	7