1.1 这些试验方法包括测定在自由落镖冲击的规定条件下导致塑料膜失效的能量。该能量表示为从指定高度落下的导弹的重量（质量），这将导致50 % 测试样本的故障。 1.2 描述了两种试验方法: 1.2.1 试验方法A 使用38.10的飞镖 ± 0.13-mm（1.500 ± 0.005英寸）直径半球形头部从0.66的高度掉落 ± 0.01米（26.0 ± 0.4英寸）。该试验方法可用于耐冲击性要求质量约为50 g至6 kg的薄膜断裂。 1.2.2 试验方法B 使用50.80的飞镖 ± 0.13毫米（2.000 ± 0.005英寸）直径半球形头部从1.52高度掉落 ± 0.03米（60.0 + 0.25, −1.70英寸）。其适用范围为约0.3千克至约6千克。 1.3 描述了两种测试技术: 1.3.1 标准技术是阶梯法。通过这种技术，根据观察到的样本结果（失败或未失败），测试期间使用的导弹重量在每个样本测试后以均匀增量减少或增加。 1.3.2 另一种技术是将试样连续分成十组进行测试。每组使用一个导弹重量，导弹重量在各组之间以均匀增量变化。 1.3.3 楼梯技术和替代技术在获得的冲击破坏重量值和确定精度方面给出了等效结果。 1.4 以国际单位制表示的数值应视为标准值。括号中的数值仅供参考。 注1: 对不因任何原因断裂的材料进行的测试被视为无效。已经注意到，某些材料可能会拉伸到某些测试仪器底部，而不会实际破裂。小组委员会D20.19目前正在考虑测试这些材料的方法。任何有兴趣参加工作组的人都应通过ASTM国际总部联系D20.19小组委员会主席。 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。 注2: 薄膜被任意定义为标称厚度不大于0.25 mm（0.010 in.）的薄板。 注3: 该试验方法在技术上等同于ISO 7765-1:1988，除了试验方法B中跌落高度的较大公差，试验方法a和B中省道直径的较小公差，以及试验方法B中通风省道井的要求 5.1.1 此外，ISO方法不允许第节中描述的替代测试技术 11 本试验方法。 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 试验方法A和B用于在50℃时确定省道的重量 % 的试样在规定的条件下失效。 一种试验方法获得的数据不能直接与另一种试验方法进行比较，也不能与采用不同条件的导弹速度、撞击面直径、有效样本直径、材料结构和镖头光洁度以及膜厚度的试验获得的数据进行比较。通过这些测试变量获得的值高度依赖于薄膜制造方法。 4.2 测试方法A和B的结果受测试薄膜质量的影响很大。因此，根据样品质量、膜规均匀性、模痕、污染物等，通过该程序获得的数据的置信限可能会发生显著变化。 4.3 试验方法A和B对于规范目的非常有用。 注4: 有了足够的数据，通常可以建立测试结果和现场性能之间的相关性。 4.4 塑料薄膜的抗冲击性虽然部分取决于厚度，但与样品厚度没有简单的相关性。因此，冲击值不能在厚度范围内归一化，而不会产生关于材料实际抗冲击性的误导性数据。这些试验方法的数据仅适用于变化不超过±25的样本 % 根据测试样本的标称或平均厚度。 4.5 薄膜采用了几种冲击试验方法。有时需要了解由不同测试方法得出的测试结果之间的关系。进行了一项研究，使用试验方法对由两种树脂（聚丙烯和线性低密度聚乙烯）制成的四层薄膜进行冲击，每种树脂具有两种薄膜厚度 D1709 （方法A）， D3420 （程序A和B），以及 D4272 .测试结果见附录。试验方法之间的结果差异 D1709 和 D4272 由于试验方法不同，因此并不罕见 D1709 表示故障引起的能量，而测试方法 D4272 是起始能量加上完成能量。当起始能量与总能量相同时，一些薄膜表现出一致性。本声明和测试数据也出现在测试方法的重要性章节和附录中 D3420 和 D4272 .

1.1 These test methods cover the determination of the energy that causes plastic film to fail under specified conditions of impact of a free-falling dart. This energy is expressed in terms of the weight (mass) of the missile falling from a specified height which would result in 50 % failure of specimens tested. 1.2 Two test methods are described: 1.2.1 Test Method A employs a dart with a 38.10 ± 0.13-mm (1.500 ± 0.005-in.) diameter hemispherical head dropped from a height of 0.66 ± 0.01 m (26.0 ± 0.4 in.). This test method can be used for films whose impact resistances require masses of about 50 g to about 6 kg to fracture them. 1.2.2 Test Method B employs a dart with a 50.80 ± 0.13-mm (2.000 ± 0.005-in.) diameter hemispherical head dropped from a height of 1.52 ± 0.03 m (60.0 + 0.25, −1.70 in.). Its range of applicability is from about 0.3 kg to about 6 kg. 1.3 Two testing techniques are described: 1.3.1 The standard technique is the staircase method. By this technique, the missile weight employed during the test is decreased or increased by uniform increments after the testing of each specimen, depending upon the result (fail or not fail) observed for the specimen. 1.3.2 The alternative technique provides for testing specimens in successive groups of ten. One missile weight is employed for each group and the missile weight is varied in uniform increments from group to group. 1.3.3 The staircase technique and the alternative technique give equivalent results both as to the values of impact failure weight which are obtained and as to the precisions with which they are determined. 1.4 The values stated in SI units are to be regarded as standard. The values stated in parentheses are for information only. Note 1: Tests on materials that do not break, for any reason, are not considered to be valid. It has been noted that certain materials may stretch so far as to bottom out at the base of certain test instruments without actually rupturing. Subcommittee D20.19 is currently considering methods for testing these materials. Anyone interested in participating in a Task Group should contact the Chairman of Subcommittee D20.19 through ASTM International Headquarters. 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. Note 2: Film has been arbitrarily defined as sheeting having nominal thickness not greater than 0.25 mm (0.010 in.). Note 3: This test method is technically equivalent to ISO 7765-1:1988, with the exception of a larger tolerance on the drop height in Test Method B, smaller tolerances on the dart diameters for Test Methods A and B, and the requirement for a vented dart well in 5.1.1 . Also, the ISO method does not allow the alternative testing technique described in Section 11 of this test method. 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 Test Methods A and B are used to establish the weight of the dart when 50 % of the specimens fail under the conditions specified. Data obtained by one test method cannot be compared directly with the other test method nor with those obtained from tests employing different conditions of missile velocity, impinging surface diameter, effective specimen diameter, material construction and finish of the dart head, and film thickness. The values obtained by these test variables are highly dependent on the method of film fabrication. 4.2 The results obtained by Test Methods A and B are greatly influenced by the quality of film under test. The confidence limits of data obtained by this procedure can, therefore, vary significantly, depending on the sample quality, uniformity of film gage, die marks, contaminants, etc. 4.3 Test Methods A and B have been found useful for specification purposes. Note 4: With sufficient data, correlation between test results and field performance can usually be established. 4.4 The impact resistance of plastic film, while partly dependent on thickness, has no simple correlation with sample thickness. Hence, impact values cannot be normalized over a range of thickness without producing misleading data as to the actual impact resistance of the material. Data from these test methods are comparable only for specimens that vary by no more than ±25 % from the nominal or average thickness of the specimens tested. 4.5 Several impact test methods are used for film. It is sometimes desirable to know the relationships among test results derived by different test methods. A study was conducted in which four films made from two resins (polypropylene and linear low-density polyethylene), with two film thicknesses for each resin, were impacted using Test Methods D1709 (Method A), D3420 (Procedures A and B), and D4272 . The test results are shown in the Appendix. Differences in results between Test Methods D1709 and D4272 are not unusual since Test Methods D1709 represents failure initiated energy, while Test Method D4272 is initiation plus completion energy. Some films exhibit consistency when the initiation energy is the same as the total energy. This statement and the test data also appear in the significance sections and appendixes of Test Methods D3420 and D4272 .