1.1 本试验方法包括测定塑料浸没时的相对吸水率。本试验方法适用于所有类型塑料的试验，包括铸造、热模塑和冷模塑树脂产品，以及棒状和管状以及厚度大于等于0.13 mm（0.005 in.）的片材的均质和层压塑料。 1.2 以国际单位制给出的值视为标准值。括号中的值仅供参考。 注1: 本试验方法和ISO 62在技术上等同于 6.2 已使用。 1.3 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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。 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 吸水率试验方法有两个主要功能:第一，作为材料吸水比例的指南，因此，在确定了水分与电气或机械性能、尺寸或外观之间关系的情况下，作为暴露于水或潮湿条件对此类性能影响的指南；第二，作为产品均匀性的控制测试。当对成品进行测试时，第二个功能特别适用于板材、棒材和管臂。 4.2 根据根据 8.1 和 8.4 被发现是有用的。 4.3 液体的理想扩散 4. 进入聚合物是浸泡时间平方根的函数。饱和时间在很大程度上取决于试样厚度。例如 表1 显示了不同厚度尼龙-6的近似时间饱和时间。 4.4 塑料的含水量与电绝缘电阻、介电损耗、机械强度、外观和尺寸等特性密切相关。 吸水引起的含水量变化对这些特性的影响在很大程度上取决于暴露类型（浸入水中或暴露于高湿度）、零件形状和塑料的固有特性。对于非均质材料，例如层压形式，吸水率有时会因边缘和表面的不同而有很大差异。即使对于其他均质材料，也可以观察到，通过切割边缘的压力略大于通过模制表面的压力。 因此，将吸水率与表面积相关联的尝试通常必须限于密切相关的材料和形状相似的试样:对于密度变化很大的材料，需要考虑体积吸水率值与重量吸水率值之间的关系。

1.1 This test method covers the determination of the relative rate of absorption of water by plastics when immersed. This test method is intended to apply to the testing of all types of plastics, including cast, hot-molded, and cold-molded resinous products, and both homogeneous and laminated plastics in rod and tube form and in sheets 0.13 mm (0.005 in.) or greater in thickness. 1.2 The values given in SI units are to be regarded as standard. The values stated in parentheses are for information only. Note 1: This test method and ISO 62 are technically equivalent when the test specimen described in 6.2 is used. 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. 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 This test method for rate of water absorption has two chief functions: first, as a guide to the proportion of water absorbed by a material and consequently, in those cases where the relationships between moisture and electrical or mechanical properties, dimensions, or appearance have been determined, as a guide to the effects of exposure to water or humid conditions on such properties; and second, as a control test on the uniformity of a product. This second function is particularly applicable to sheet, rod, and tube arms when the test is made on the finished product. 4.2 Comparison of water absorption values of various plastics made on the basis of values obtained in accordance with 8.1 and 8.4 have been found useful. 4.3 Ideal diffusion of liquids 4 into polymers is a function of the square root of immersion time. Time to saturation is strongly dependent on specimen thickness. For example, Table 1 shows the time to approximate time saturation for various thickness of nylon-6. 4.4 The moisture content of a plastic is very intimately related to such properties as electrical insulation resistance, dielectric losses, mechanical strength, appearance, and dimensions. The effect upon these properties of change in moisture content due to water absorption depends largely on the type of exposure (by immersion in water or by exposure to high humidity), shape of the part, and inherent properties of the plastic. With nonhomogeneous materials, such as laminated forms, the rate of water absorption is sometimes known to be widely different through each edge and surface. Even for otherwise homogeneous materials, it has been observed to be slightly greater through cut edges than through molded surfaces. Consequently, attempts to correlate water absorption with the surface area must generally be limited to closely related materials and to similarly shaped specimens: For materials of widely varying density, relation between water-absorption values on a volume as well as a weight basis needs to be considered.