This test method determines the total acidity, expressed as HCl, of crude or modified isocyanates. The test method is applicable to products derived from toluene diisocyanate, methylene-bis-(4-phenylisocyanate), and polymethylene polyphenyl isocyanates.

Formerly under the jurisdiction of Committee D20 on Plastics, this test method was withdrawn in November 2003 and replaced by Test Method D 5523 for Polyurethane Raw Materials Acidity by Argentometric Determination of Hydrolyzable Chlorine in Monomeric, Aromatic Isocyanates, Test Method D 5629 for Polyurethane Raw Materials Determination of Acidity in Low-Acidity Aromatic Isocyanates and Polyurethane Prepolymers, and Test Method D 6099 for Polyurethane Raw Materials: Determination of Acidity in Moderate to High Acidity Aromatic Isocyanates.

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1.1 This test method determines the total acidity, expressed as HCl, of crude or modified isocyanates. The test method is applicable to products derived from toluene di iso cyanate, methylene-bis-(4-phenyl iso cyanate), and polymethylene polyphenyl iso cyanates. (See Note 1.)

1.2 The values stated in SI units are to be regarded as the standard.

1.3 This standard does not purport to address all of the safety problems, 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 hazards statements see 7.1 and Note 2.