1.1 本试验方法测量用作聚氨酯原料的单体芳香族异氰酸酯的可水解氯含量，并将其表示为HCl酸度。本试验方法适用于甲苯二异氰酸酯（TDI）和单体亚甲基二（苯基异氰酸酯），称为MDI。单体芳香异氰酸酯中可水解氯和酸度的主要来源是氨甲酰氯化物、酸性氯化物和溶解光气。所有这些化合物与醇和水反应生成盐酸。 1.2 本试验方法仅适用于单体异氰酸酯，其中所有酸度均来源于溶剂分解产生HCl的物质。 1.3 以国际单位制表示的数值应视为标准。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 注1: 没有已知的ISO等效于本标准。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法适用于表征TDI和MDI的研究或质量控制。 5.2 本试验方法旨在克服在试剂醇溶剂存在下使用玻璃电极进行低酸度测定的问题。试剂醇包含酸性和碱性物质，这使低酸度下的玻璃电极方法复杂化。

1.1 This test method measures the hydrolyzable chlorine content of monomeric, aromatic isocyanates used as polyurethane raw materials and expresses it as HCl acidity. The test method is applicable to toluene diisocyanate (TDI) and monomeric methylene di(phenylisocyanate), known as MDI. The main sources of hydrolyzable chlorine and, therefore, acidity in monomeric aromatic isocyanates are carbamyl chlorides, acid chlorides, and dissolved phosgene. All of these compounds react with alcohols and water to form hydrochloric acid. 1.2 This test method applies only to monomeric isocyanates in which all of the acidity is derived from species that generate HCl on solvolysis. 1.3 The values stated in SI units are to be regarded as the standard. 1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Note 1: There is no known ISO equivalent to this standard. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 This test method is suitable for research or for quality control to characterize TDI and MDI. 5.2 This test method was developed to overcome problems with low-level acidity determinations that use glass electrodes in the presence of reagent alcohol solvents. Reagent alcohols contain acidic and basic species, which complicate the glass electrode methods at low levels of acidity.