This standard was last reviewed and confirmed in 2020. Therefore this version remains current.
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.
Status : PublishedPublication date : 1999-10
Edition : 1Number of pages : 7
Technical Committee:Thermosetting materials
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