ASTM D4272-99
(Test Method)Standard Test Method for Total Energy Impact of Plastic Films By Dart Drop
Standard Test Method for Total Energy Impact of Plastic Films By Dart Drop
SCOPE
1.1 This test method describes the determination of the total energy impact of plastic films by measuring the kinetic energy lost by a free-falling dart that passes through the film.
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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 4272 – 99
Standard Test Method for
Total Energy Impact of Plastic Films By Dart Drop
This standard is issued under the fixed designation D 4272; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope * 2.2 ISO Standard:
ISO 7765–2
1.1 This test method describes the determination of the total
energy impact of plastic films by measuring the kinetic energy
3. Terminology
lost by a free-falling dart that passes through the film.
3.1 Definitions of Terms Specific to This Standard:
1.2 The values stated in SI units are to be regarded as the
3.1.1 free-fall time—the measured time required for the dart
standard. The values given in parentheses are for information
to travel through the sensing area with no film specimen in the
only.
clamp.
1.3 This standard does not purport to address all of the
3.1.2 missile weight—the weight of the dart plus the total
safety concerns, if any, associated with its use. It is the
value of incremental weights attached, including the locking
responsibility of the user of this standard to establish appro-
collar.
priate safety and health practices and determine the applica-
3.1.3 test-fall time—the measured time for the dart to travel
bility of regulatory limitations prior to use.
through the sensing area with a film specimen in the clamp.
NOTE 1—The ISO reference for this test method is ISO 7765-2;
however, this test method is not equivalent to Test Method D 4272. The
4. Summary of Test Method
ISO test method calls for a direct readout of energy by using a load cell
4.1 The velocity of a freely falling dart of specified shape
as part of the impactor head, while Test Method D 4272 calls for a
that has passed through a sheet of plastic film is determined by
constant weight impactor, then measuring the time of travel through a
means of a photoelectric speed trap. The kinetic energy
given distance to get energy values. Therefore, the two are not equivalent
in this respect. corresponding to this velocity is calculated and compared with
the kinetic energy of the same dart measured without a plastic
2. Referenced Documents
film in place. The loss in kinetic energy, suffered by the dart
2.1 ASTM Standards:
that ruptured the film, is used as an index of impact resistance.
D 374 Test Methods for Thickness of Solid Electrical Insu-
5. Significance and Use
lation
D 618 Practice for Conditioning Plastics and Electrical
5.1 Evaluation of the impact toughness of film is important
Insulating Materials for Testing in predicting the performance of a material in applications such
D 1709 Test Methods for Impact Resistance of Plastic Film
as packaging, construction, and other uses. The test simulates
by the Free-Falling Dart Method the action encountered in applications where moderate-velocity
D 3420 Test Method for Dynamic Ball Burst (Pendulum)
blunt impacts occur in relatively small areas of film.
Impact Resistance of Plastic Film 5.2 The values obtained by this test method are highly
E 171 Specification for Standard Atmospheres for Condi-
dependent on the method and conditions of film fabrication as
tioning and Testing Flexible Barrier Materials well as the type and grade of resin.
E 691 Practice for Conducting an Interlaboratory Study to
5.3 Test methods employing different missile velocities,
Determine the Precision of a Test Method impinging surface diameters, or effective specimen diameters
will most likely produce different results. Data obtained by this
test method cannot necessarily be compared directly with those
obtained by the other test methods.
This test method is under the jurisdiction of ASTM Committee D-20 on Plastics
and is the direct responsibility of Subcommittee D 20.19 on Film and Sheeting. 5.4 The impact resistance of a film, while partly dependent
Current edition approved Aug. 10, 1999. Published September 1999. Originally
on thickness, does not have a simple correlation with sample
published as D 4272 – 83. Last previous edition D 4272 – 96.
thickness. Hence, impact values expressed in joules (ft·lbf)
Annual Book of ASTM Standards, Vol 10.01.
Annual Book of ASTM Standards, Vol 08.01
Annual Book of ASTM Standards, Vol 08.02.
5 7
Annual Book of ASTM Standards,Vol 15.09. Available from American National Standards Institute, 11 W. 42nd St., 13th
Annual Book of ASTM Standards, Vol 14.02. Floor, New York, NY 10036.
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D4272–99
FIG. 1 Elements of an Instrumented Dart Drop System
normalized over a range of thickness will not necessarily be results derived by different test methods. A study was con-
linear with thickness. Data from this test method are compa- ducted in which four films made from two resins (polypropy-
rable only for specimens that vary by no more than 615 % lene and linear low-density polyethylene), with two film
from the nominal or average thickness of the specimens tested. thicknesses for each resin, were impacted using Test Methods
5.5 The test results obtained by this test method are greatly D 1709 (Test Method A), Test Method D 3420 (Procedures A
influenced by the quality of film under test. The influence of and B), and Test Method D 4272. The test results are shown in
variability of data obtained by this procedure will, therefore, Appendix X2. Differences in results between Test Methods
depend strongly on the sample quality, uniformity of film gage, D 1709 and D 4272 are expected since Test Methods D 1709
the presence of die marks, contaminants, etc. represents failure-initiated energy, while Test Method D 4272
5.6 Several impact test methods are used for film. It is is initiation plus completion energy. Some films may show
sometimes desirable to know the relationships among test consistency when the initiation energy is the same as the total
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D4272–99
energy. This statement and the test data also appear in the 8.3 Position the dart vertically in the holder and clamp the
significance and appendixes sections of Test Methods D 1709 dart with the dart-holding device. Allow a few seconds for any
and D 3420. vibration to subside and release the dart. Record the free-fall
time.
8.4 Repeat 8.3 four more times. Average the five measured
6. Apparatus
times and record as t .
6.1 Free-Falling Dart, as described in Test Methods
8.4.1 The time reading of each of the five free-falls shall be
D 1709, Test Method A.
within 630 μs of the average. If it is not, check the timing
NOTE 2—Pneumatically operated annular clamps have been success-
system, the position of the sensing element, etc. until this
fully employed with a supply of compressed air capable of maintaining a
repeatability is obtained with five free-falls.
pressure of at least 0.552 MPa (80 psi) sufficient to prevent film slippage.
8.4.2 The dart shall not vibrate or rotate in the holder and
Pressure may be reduced if fracture of the film due to clamping occurs.
shall fall straight.
Clamping diameter is 127 mm (5 in.).
8.4.3 To ensure consistency in drop of the dart and position
−5
6.2 Time Counter, with a sensitivity to measure in 10 s.
of impact of the dart on the film, the dart tip next to the holder
6.3 Light-Sensitive Speed Trap, to activate the time counter
can be scribed so that it can be lined up in the same position
device.
each time.
6.4 Micrometer, accurate to 60.0025 mm (60.0001 in.) for
measuring specimen thickness (see Test Methods D 374). 9. Conditioning
6.5 Darts, with 38.106 0.13-mm (1.500 6 0.005-in.) diam-
9.1 Conditioning—Unless otherwise specified, condition
eter hemispherical stainless steel head. Dart weight equals 227
the test specimens at 23 6 2°C (73.4 6 3.6°F) and 50 6 5%
g (0.5 lb).
relative humidity for not less than 40 h prior to test in
accordance with Procedure A of Practice D 618. In cases of
NOTE 3—Stem diameter of 9.52 mm (0.37 in.) has been found
disagreement, the tolerances shall be 61°C (61.8°F) and 62%
satisfactory to resist bending.
relative humidity.
6.6 Dart Weights (five), starting at 227 g (0.5 lb) and
9.2 Test Conditions—Conduct tests in the standard labora-
increasing in 227-g (0.5-lb) increments to 1135 g (2.5 lb).
tory atmosphere of 23 6 2°C (73.4 6 3.6°F) an
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