1.1 此测试方法 2. 涵盖了使用Elmendorf型撕裂测试仪在撕裂开始后通过指定长度的塑料薄膜或非刚性片材传播撕裂的平均力的测定。引用了两个试样，一个是矩形试样，另一个是恒定半径试验长度试样。后者应为首选样本或裁判样本。 1.2 因为( 1. )难以选择一致相同的试样( 2. )某些塑料薄膜中不同程度的取向，以及( 3. )在测试高延展性或高定向材料或两者时发现的困难，测试结果的再现性可能是可变的，并且在某些情况下，不好或具有误导性。试验方法中规定了一些材料可能出现的倾斜定向撕裂。 1.3 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。 1.4 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。 具体的预防说明见 13.1 . 注1: 薄膜被任意定义为标称厚度不大于0.25毫米（0.010英寸）的片材。 注2: 本标准等同于ISO 6383-2。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 4.1 该测试方法在对各种塑料薄膜和厚度相当的薄板的相对撕裂阻力进行排名方面具有价值。经验表明，该测试在延展性相对较低的薄膜和片材上具有最佳可靠性。对延展性更强的薄膜的可变伸长率和倾斜撕裂效应使其无法用作这些类型塑料的精确生产控制工具。只有在证明特定材料的数据具有可接受的可重复性后，才能将该测试方法用于规范验收测试。只有在用多种不同的薄膜证明了该测试方法对特定应用的有用性后，才能使用该测试方法进行服务评估。 4.2 该测试方法已被广泛用作包装应用中使用的塑料薄膜和薄板的抗撕裂性指标之一。 虽然并不总是能够将薄膜撕裂数据与其其他机械或韧性特性相关联，但该测试方法的装置提供了一种控制手段，用于在接近实际包装服务中发现的一些应变率的应变率下撕裂试样。 4.3 由于在制造过程中的取向，塑料薄膜和片材在抗撕裂性方面经常表现出明显的各向异性。由于一些薄膜在撕裂过程中大大伸长，甚至在这种测试方法中遇到的相对快速的加载速率下，这一事实使情况变得更加复杂。这种伸长率又取决于膜的取向和聚合物的固有机械性能。这些因素使得一些薄膜的抗撕裂性在两组样品之间可重复到±5 % 平均值的，而其他可能显示的再现性不超过±50 %. 4.4 通过本试验方法获得的数据可作为试验方法数据的补充 2004年1月 ，其中所述试样以每分钟50毫米（2英寸）的速率应变。然而，两种测试方法的试样几何形状和测试速度不同。在该试验方法中，撕裂速率在7.6至46米（300至1800英寸）/分钟的范围内，同时作为抗撕裂性的函数而变化。 4.5 撕裂力和试样厚度之间没有直接的线性关系。该试验方法的数据表示为撕裂力，单位为毫牛顿（或克力，如果需要），还报告了试样厚度。但不同厚度试样的数据集通常不具有可比性。因此，只比较相同厚度的数据。 4.6 对于许多材料，可能有一个规范要求使用这种测试方法，但在遵守规范时，会优先进行一些程序修改。 因此，在使用此测试方法之前，建议参考该材料规范。分类系统表1 4000天 列出了目前存在的ASTM材料标准。

1.1 This test method 2 covers the determination of the average force to propagate tearing through a specified length of plastic film or nonrigid sheeting after the tear has been started, using an Elmendorf-type tearing tester. Two specimens are cited, a rectangular type, and one with a constant radius testing length. The latter shall be the preferred or referee specimen. 1.2 Because of ( 1 ) difficulties in selecting uniformly identical specimens, ( 2 ) the varying degree of orientation in some plastic films, and ( 3 ) the difficulty found in testing highly extensible or highly oriented materials, or both, the reproducibility of the test results may be variable and, in some cases, not good or misleading. Provisions are made in the test method to address oblique directional tearing which may be found with some materials. 1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 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. Specific precautionary statements are given in 13.1 . Note 1: Film has been arbitrarily defined as sheeting having nominal thickness not greater than 0.25 mm (0.010 in.). Note 2: This standard is equivalent to ISO 6383-2. 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 is of value in ranking relative tearing resistance of various plastic films and thin sheeting of comparable thickness. Experience has shown the test to have its best reliability on relatively less extensible films and sheeting. Variable elongation and oblique tearing effects on the more extensible films preclude its use as a precise production-control tool for these types of plastics. This test method should be used for specification acceptance testing only after it has been demonstrated that the data for the particular material are acceptably reproducible. This test method should be used for service evaluation only after its usefulness for the particular application has been demonstrated with a number of different films. 4.2 This test method has been widely used as one index of the tearing resistance of plastic film and thin sheeting used in packaging applications. While it is not always be possible to correlate film tearing data with its other mechanical or toughness properties, the apparatus of this test method provides a controlled means for tearing specimens at straining rates approximating some of those found in actual packaging service. 4.3 Due to orientation during their manufacture, plastic films and sheeting frequently show marked anisotropy in their resistance to tearing. This is further complicated by the fact that some films elongate greatly during tearing, even at the relatively rapid rates of loading encountered in this test method. The degree of this elongation is dependent in turn on film orientation and the inherent mechanical properties of the polymer from which it is made. These factors make tear resistance of some films reproducible between sets of specimens to ±5 % of the mean value, while others potentially show no better reproducibility than ±50 %. 4.4 Data obtained by this test method may supplement that from Test Method D1004 , wherein the specimen is strained at a rate of 50 mm (2 in.) per minute. However, specimen geometry and testing speed of the two test methods are dissimilar. The rate of tearing in this test method, while varying as a function of resistance to tear, is in the range from 7.6 to 46 m (300 to 1800 in.)/min. 4.5 There is not a direct, linear relationship between tearing force and specimen thickness. Data from this test method are expressed as tearing force in millinewtons (or grams-force, if desired), with specimen thickness also reported. But sets of data from specimens of dissimilar thickness are usually not comparable. Therefore, only data at the same thickness is compared. 4.6 For many materials, there may be a specification that requires the use of this test method, but with some procedural modifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that material specification before using this test method. Table 1 of Classification System D4000 lists the ASTM materials standards that currently exist.