1.1 这些试验方法包括通用聚氯乙烯（PVC）树脂粉末混合时间的测定。 1.2 以国际单位制表示的数值应视为标准值。 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: 国际标准化组织 4574-2019涵盖了该ASTM方法的主要主题。 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====== 5.1 PVC颗粒接受增塑剂并成为干燥自由流动粉末的能力与树脂的内部孔隙结构、树脂温度、增塑剂温度和所用增塑剂有关。通过选择合适的增塑剂并保持树脂和增塑剂的均匀温度，可以根据树脂吸收增塑剂的速度对树脂进行分类。使用这些测试方法可以确定树脂对特定密集混合操作的适用性。

1.1 These test methods cover the determination of the powder-mix time of a general-purpose poly(vinyl chloride) (PVC) resin. 1.2 The values stated in SI units are to be regarded as 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: ISO 4574-2019 is covering the primary subject of this ASTM method. 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 ====== 5.1 The ability of PVC granules to accept a plasticizer and become a dry free-flowing powder is related to the internal pore structure of the resin, resin temperature, plasticizer temperature, and the plasticizer used. By choosing an applicable plasticizer and maintaining a uniform temperature for the resin and plasticizer, it is possible to classify resins by how rapidly they absorb plasticizer. Resin suitability for a specific intensive mixing operation can be ascertained using these test methods.