【国外标准】 Standard Test Method for Puncture-Propagation Tear Resistance of Plastic Film and Thin Sheeting

4.1 The puncture-propagation of tear test measures the resistance of a material to snagging, or more precisely, to dynamic puncture and propagation of that puncture resulting in a tear. Failures due to snagging occur in a variety of end uses, including industrial bags, liners, and tarpaulins. The units reported in this test method are Newtons (tear resistance).4.2 Experience has shown that for many materials puncture does not contribute significantly to the force value determined, due to the sharpness of the propagating probe used. However, comparing the results of prepunctured test specimens with normal nonpunctured specimens will give an indication of the extent of any puncture resistance in the reported result.4.3 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 current ASTM materials standards.1.1 This test method covers the determination of the dynamic tear resistance of plastic film and thin sheeting subjected to end-use snagging-type hazards.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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: Film has been arbitrarily defined as sheeting having nominal thickness not greater than 0.25 mm (0.010 in.).NOTE 2: There is no known ISO equivalent to this standard.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.