1.1 本试验方法包括测定各种透明和着色涂层的非挥发性物质的体积百分比。所使用的方法应比在试验方法中使用液体置换技术提供更快、更准确的结果 697年 特别是对于难以湿润或含有空隙、裂缝或其他缺陷的涂层。精度的提高源于氦气在压力下穿透非常小的孔隙和干燥薄膜表面不规则性的优越能力。这提供了比通过液体置换获得的更准确的空隙体积测定。 1.2 该技术将在以下约束条件下提供结果: 1.2.1 氦气比重瓶的稳定性大于±0.005 cm 3. . 1.2.2 试样重量大于1g。 1.3 以英寸-磅单位表示的值应视为标准值。括号中给出的值是对SI单位的数学转换，仅供参考，不被视为标准值。 1.4 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建立适当的安全、健康和环境实践，并确定监管限制的适用性。 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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 该试验方法测量从给定体积的液体涂层获得的干涂层的体积。该值可用于计算涂层的挥发性有机物含量（VOC），并可用于估算不同涂层产品可获得的覆盖范围（单位体积指定干膜厚度下覆盖的表面平方英尺）。 注1: 在实践中 1960年 第10.3.1段，给出了使用非挥发性体积百分比计算VOC含量的公式。在此方法之前，不存在测量非挥发性体积百分比的令人满意的程序（见实践中的注释11 1960年 ). 注2: 由于涂层的实际覆盖率包括膜的空隙体积和孔隙率，因此根据该方法计算的覆盖率值将不准确，即实际覆盖率将更大。涂层的颜料与粘合剂的比率（P/B）越高，或含空隙材料（乳胶、空心珠等）含量越高，或者两者都有，覆盖率计算的偏差越大（试验方法中的偏差也越小 697年 ). 4.2 由于各种原因，涂层获得的体积不挥发值通常不等于配方中原料重量和体积的简单线性相加所预测的值。 一个原因是树脂在溶剂中的溶液所占的体积可能与单独成分的总体积相同、更大或更小。树脂溶液的这种收缩或膨胀由许多因素控制，其中一个因素是树脂和溶剂的溶解度参数之间的扩散程度和方向。 4.3 颜料颗粒的空间构型和颜料颗粒被粘合剂填充的程度也影响干涂膜的体积。在临界颜料体积浓度以上，由于颜料颗粒之间未填充空隙的增加，干膜的表观体积显著大于理论体积。 在这种情况下，应仔细考虑使用体积非挥发性物质值，因为体积的增加主要是由于这些空隙中的空气。 4.4 对于薄膜，临界颜料体积效应的问题通常不受关注。然而，对于高聚氯乙烯（PVC）膜，即使在高压下，也很难进行空气空隙的液体置换。氦解决了这个问题，因为它作为一种气体，即使在低压下也能很容易地渗透和置换空气、水和挥发性溶剂。吹扫气体比重瓶会将这些物质从薄膜中冲洗出来。

1.1 This test method covers the determination of the percent volume nonvolatile matter of a variety of clear and pigmented coatings. The approach used should provide faster and more accurate results than the use of the liquid displacement technique in Test Method D2697 , particularly for coatings that are difficult to wet or that contain voids, cracks or other defects. The improvement in accuracy stems from the superior ability of helium gas under pressure to penetrate very small pores and surface irregularities in dried films. This provides a more accurate determination of void volumes than can be obtained via liquid displacement. 1.2 The technique will provide results under the following constraints: 1.2.1 The stability of the helium gas pycnometer is greater than ±0.005 cm 3 . 1.2.2 Test specimen weights are greater than 1 g. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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. 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 ====== 4.1 This test method measures the volume of dry coating obtainable from a given volume of liquid coating. This value is useful for calculating the volatile organic content (VOC) of a coating and could be used to estimate the coverage (square feet of surface covered at a specified dry film thickness per unit volume) obtainable with different coating products. Note 1: In Practice D3960 paragraph 10.3.1, the equation for calculating the VOC content using the percent volume nonvolatile is given. Prior to this method a satisfactory procedure for measuring percent volume nonvolatile did not exist (see Note 11 in Practice D3960 ). Note 2: Since the actual coverage of a coating includes the void volume and the porosity of the film, the coverage value calculated from this method will be inaccurate by that amount, that is, the actual coverage will be greater. The higher the pigment to binder ratio (P/B) of a coating or the higher content of void containing material (latices, hollow beads, etc.) or both, the greater will be the deviation of the coverage calculation (This is also true to a lesser degree with Test Method D2697 ). 4.2 For various reasons the volume nonvolatile value obtained for a coating is often not equal to that predicted from simple linear addition of the weights and volumes of the raw materials in a formulation. One reason is that the volume occupied by a solution of resin in solvent may be the same, greater, or less than the total volume of the separate ingredients. Such contraction or expansion of resin solutions is governed by a number of factors, one of which is the extent and direction of spread between solubility parameters of the resin and solvent. 4.3 The spatial configuration of the pigment particles and the degree to which the pigment particles are filled with the binder also affect the volume of a dry coating film. Above the critical pigment volume concentration, the apparent volume of the dry film is significantly greater than theoretical due to the increase in unfilled voids between pigment particles. The use of volume nonvolatile matter values in such instances should be carefully considered as the increased volume is largely due to air trapped in these voids. 4.4 For thin films, the issue of critical pigment volume effects is usually not a concern. With high poly(vinyl chloride) (PVC) films, however, liquid displacement of air voids takes place with difficulty even under high pressures. Helium solves this problem since, as a gas, it readily penetrates and displaces air, water, and volatile solvents even at low pressures. Purging the gas pycnometer flushes these materials from the film.