Over deze norm
1.1 This test method2 covers the determination of the tear resistance of flexible plastic film and sheeting at very low rates of loading, 51 mm (2 in.)/min. and is designed to measure the force to initiate tearing. The specimen geometry of this test method produces a stress concentration in a small area of the specimen. The maximum stress, usually found near the onset of tearing, is recorded as the tear resistance in newtons (or pounds-force). The method is not applicable for film or sheeting material where brittle failures occur during testing or where maximum extension is greater than 101.6 mm (4 in.).
1.1.1 Although resistance to tear can be expressed in newtons per microns, (pounds-force per mil) of specimen thickness, this is only advisable where correlation for the particular material being tested has been established. In most cases, comparison between films of dissimilar thickness is not valid.
1.2 Constant-Rate-of-Grip Separation Test—This test method employs a constant rate of separation of the grips holding the test specimen.
1.2.1 Specimen extension may be measured in this test method by grip separation.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided 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 and health practices and determine the applicability of regulatory limitations prior to use.
|Nederlandse titel||Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting|
|Engelse titel||Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting|