1.1 本试验方法用于在不破坏现有甲醛平衡的情况下测定乳液聚合物中的游离甲醛（HCHO）。使用丙烯酸、丙烯腈-丁二烯、羧基化苯乙烯-丁二烯和聚醋酸乙烯酯乳液聚合物对该程序进行了评估。本试验方法也适用于其他成分的乳液聚合物。本试验方法的既定工作范围为0.05至15 ppm甲醛。乳液聚合物必须稀释以满足工作范围。 1.2 本试验方法最大限度地减少了因乳液聚合物的物理或化学性质变化而引起的游离甲醛浓度变化。 1.3 当以所述方式使用时，该试验方法没有已知限制。乳液聚合物试样必须用pH值与乳液相似的稀释剂制备。使用不合适的pH值可能会破坏甲醛平衡，并导致不正确的甲醛水平。 1.4 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。 1.5 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。 1.6 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 由于需要计算乳液聚合物中的游离甲醛水平，有必要在不破坏任何可能产生或消耗甲醛的平衡的情况下进行测定。本试验方法提供了一种在不破坏现有平衡的情况下测定乳液聚合物中游离甲醛ppm水平的方法。

1.1 This test method is used for the determination of free formaldehyde (HCHO) in emulsion polymers without upsetting existing formaldehyde equilibria. The procedure has been evaluated using acrylic, acrylonitrile-butadiene, carboxylated styrene-butadiene and polyvinyl acetate emulsion polymers. This test method may also be applicable for emulsion polymers of other compositions. The established working range of this test method is from 0.05 to 15 ppm formaldehyde. Emulsion polymers must be diluted to meet the working range. 1.2 This test method minimizes changes in free formaldehyde concentration that can result from changes in the physical or chemical properties of an emulsion polymer. 1.3 There are no known limitations to this test method when used in the manner described. The emulsion polymer test specimen must be prepared with a diluent that has a pH similar to that of the emulsion. Use of an inappropriate pH may upset formaldehyde equilibria and result in incorrect formaldehyde levels. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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. 1.6 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 With the need to calculate free formaldehyde levels in emulsion polymers, it is necessary to make the determination without upsetting any equilibria that might generate or deplete formaldehyde. This test method provides a means for determining ppm levels of free formaldehyde in emulsion polymers without upsetting existing equilibria.