1.1 本试验方法包括在0.76 mm（0.030 in.）的塑料薄膜和薄板的给定试样温度下测定无约束线性热收缩程度厚度或更小。本试验方法不包括某些材料中溶剂损失引起的收缩。 1.2 以国际单位制表示的数值应视为标准值。括号中给出的值是英寸-磅单位的数学转换，仅供参考，不被视为标准值。 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: 本标准和ISO 11501涉及相同的主题，但技术内容不同。 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 作为制造过程的结果，内部应力可能锁定在薄膜中，可通过加热释放。收缩发生的温度与用于制造薄膜的加工技术有关，也可能与基体树脂中的相变有关。收缩幅度将随薄膜温度而变化。 4.2 通过在材料收缩范围内的几个温度下进行测量，可以通过本试验方法表征由特定工艺产生的特定材料的收缩。 4.3 在特定情况下进行表征后，通常仅在一个选定温度下测量收缩率就足够了，用于工艺或质量控制，或两者兼而有之。

1.1 This test method covers determination of the degree of unrestrained linear thermal shrinkage at given specimen temperatures of plastic film and sheeting of 0.76 mm (0.030 in.) thickness or less. This test method does not cover shrinkage from loss of solvent in some materials. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered 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: This standard and ISO 11501 address the same subject matter, but differ in technical content. 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 As a result of the manufacturing process, internal stresses may be locked into the film which can be released by heating. The temperature at which shrinkage will occur is related to the processing techniques employed to manufacture the film and may also be related to a phase transition in the base resin. The magnitude of the shrinkage will vary with the temperature of the film. 4.2 Shrinkage of a particular material produced by a particular process may be characterized by this test method by making measurements at several temperatures through the shrinkage range of the material. 4.3 Following a characterization in a particular case, it is usually sufficient thereafter to measure shrinkage at only one selected temperature for purposes of process or quality control, or both.