1.1 本规程涵盖了将一滴液体应用于涂料表面、基材或预制盘时接触角的测量。 1.2 有两种接触角，前进和后退。本标准仅涉及推进接触角。 1.3 本实施规程旨在补充制造商对用于进行测量的设备的说明，但不打算更换这些设备。 1.4 常见的测试液体是水，但也可以使用许多其他液体，如溶剂、表面活性剂和分散剂溶液，甚至液体涂料。 1.5 本实践基于测角法，该方法涉及在固体基质上观察试验液体的固定液滴。 1.6 尽管接触角由表面张力决定，但本标准不能直接用于测量表面张力。 1.7 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.8 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。 1.9 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 本标准有助于表征表面的润湿性。易于润湿的表面是指涂层更有可能提供良好的附着力和外观，并且不太可能出现与表面张力相关的缺陷，例如爬行、凹坑、针孔和桔皮。 5.2 本标准还可用于测试颜料表面的润湿性，特别是通过潜在的表面活性剂或树脂基分散剂或研磨基质。易润湿的颜料更容易分散，感兴趣的湿颜料的分散剂/研磨基质更有可能很好地分散这些颜料。 5.3 尽管接触角由试验液体和试验表面的表面张力决定，但该角度不能直接提供表面张力值。 5.4 较低的前进接触角值（<45°）表示润湿，10到20°表示润湿良好。 5.5 水可用作测试液体（通过前进接触角）确定表面是亲水（角度<45°）、疏水（角度>90°）还是介于两者之间（角度45到90°）。水接触角用于评估清洁操作前后的表面清洁度、水性涂料对表面润湿性的缓解程度以及冲洗过程的有效性。 5.6 有机液体（例如溶剂）也可用于表征基材、涂料或颜料。 产生的接触角取决于液体和试验表面的表面张力。低表面张力（能量）测试表面不会被高表面张力液体弄湿。 5.7 除了水和溶剂外，还可以使用表面活性剂分散液或分散剂溶液来测试颜料表面。作为测试颜料的潜在分散剂的任何测试液体必须充分润湿颜料，否则将无法作为分散剂。 5.8 接触角测量可用于绘制亲水性、低表面张力成分或污染物的存在或成分变化方面的表面。 需要使用红外显微镜等其他分析方法来识别产生接触角差异的化学部分。 5.9 该测试方法可用于几乎所有涂层和基材，并可通过将颜料粉末压缩成固体圆盘扩展到颜料。

1.1 This practice covers the measurement of the angle of contact when a drop of liquid is applied to a coated surface, substrate, or preformed disk of pigment. 1.2 There are two types of contact angles, advancing and receding. This standard deals only with advancing contact angles. 1.3 This practice is intended to supplement the manufacturer’s instructions for the device being used to make the measurements, but is not intended to replace them. 1.4 A common test liquid is water, but many other liquids such as solvents, surfactant and dispersant solutions and even liquid paints can be used. 1.5 This practice is based on goniometry, which involves the observation of a sessile drop of test liquid on a solid substrate. 1.6 Although contact angles are governed by surface tension, this standard cannot be used to measure surface tension directly. 1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.8 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. 1.9 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 standard is useful for characterizing the wettability of surfaces. A surface that is easy to wet is one over which a coating is more likely to give good adhesion and appearance and less likely to suffer surface tension related defects such as crawling, cratering, pinholing and orange peel. 5.2 This standard also can be used to test pigment surfaces for wettability, particularly by potential surfactant- or resin-based dispersants or mill bases. Easily wetted pigments are more likely to be easy to disperse and dispersants/mill bases that wet pigments of interest are more likely to disperse those pigments well. 5.3 Although the contact angle is governed by the surface tensions of the test liquid and test surface, the angle cannot provide a surface tension value directly. 5.4 A low advancing contact angle value (<45°) is indicative of wetting and angles of 10 to 20° are indicative of excellent wetting. 5.5 Water can be used as a test liquid to establish (via the advancing contact angle) whether a surface is hydrophilic (angle <45°), hydrophobic (angle >90°) or somewhere in-between (angle of 45 to 90°). Water contact angles have been used to estimate surface cleanliness before and after cleaning operations, ease of wettability of surfaces by waterborne coatings and the effectiveness of rinsing processes. 5.6 An organic liquid such as a solvent also can be used to characterize a substrate, coating or pigment. The resultant contact angle will depend on the surface tensions of the liquid and the test surface. A low surface tension (energy) test surface will not be wet by a high surface tension liquid. 5.7 In addition to water and solvents, a surfactant dispersion or dispersant solution can be used to test a pigment surface. Any test liquid that is a potential dispersant for a test pigment must wet the pigment well or it will not work as a dispersant. 5.8 Contact angle measurements can be used to map surfaces in terms of hydrophilicity, presence of low surface tension components or contaminants, or variations in composition. Other analytical methods such as infrared microscopy would be needed to identify the chemical moieties that give the contact angle differences. 5.9 This test method can be used on nearly all coatings and substrates and may be extended to pigments by compressing the pigment powder into a solid disk.