Full Description

1.1These 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.

1.2Two test methods are described:

1.2.1Test Method A employs a dart with a 38.100.13-mm (1.5000.005-in.) diameter hemispherical head dropped from a height of 0.660.01 m (26.00.4 in.). This test method can be used for films whose impact resistances require masses of about 50 g or less to about 6 kg to fracture them.

1.2.2Test Method B employs a dart with a 50.800.13-mm (2.0000.005-in.) diameter hemispherical head dropped from a height of 1.520.03 m (60.0+0.25, 1.70 in.). Its range of applicability is from about 0.3 kg to about 6 kg.

1.3Two testing techniques are described:

1.3.1The 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.

1.3.2The 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.

1.3.3The 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.

1.4The 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.

1.5This standard does not purport to address 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.

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.