1.1 这些试验方法测定甲苯二异氰酸酯、聚合物（亚甲基苯基异氰酸酯）和液体亚甲基二（苯基异氰酸酯）的比重。这些试验方法也适用于许多其他液体。（参见 注1 .) 1.1.1 试验方法A- 比重瓶测定比重，用于高精度测定。 1.1.2 试验方法B- 比重计测定比重，用于较不准确但快速的测定。 1.2 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 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。 1.4 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====== 4.1 这些测试方法可用于研究或质量控制，以表征聚氨酯产品中使用的异氰酸酯。 4.2 试验方法中公布了使用数字密度计测定比重的通用试验方法，该方法适用于异氰酸酯和其他液体 D4052号 .

1.1 These test methods determine the specific gravity of toluenediisocyanate, polymeric (methylene phenylisocyanate), and liquid methylene di(phenylisocyanate). These test methods also are applicable to many other liquids. (See Note 1 .) 1.1.1 Test Method A— Specific gravity by pycnometer, for high-accuracy determination. 1.1.2 Test Method B— Specific gravity by hydrometer, for a less accurate, but rapid, determination. 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, 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. 1.4 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 ====== 4.1 These test methods can be used for research or for quality control to characterize isocyanates used in polyurethane products. 4.2 A general test method for specific gravity using a digital density meter, which applies to isocyanates as well as other liquids is published in Test Method D4052 .