ASTM D5734-95
(Test Method)Standard Test Method for Tearing Strength of Nonwoven Fabrics by Falling-Pendulum (Elmendorf) Apparatus
Standard Test Method for Tearing Strength of Nonwoven Fabrics by Falling-Pendulum (Elmendorf) Apparatus
SCOPE
1.1 This test method covers the measurement of the average force required to propagate a single-rip tear starting from a cut in a nonwoven fabric using a falling-pendulum (Elmendorf) apparatus.
1.2 This standard Elmendorf tear tester with interchangeable pendulums has become the preferred test apparatus for determining tearing strength up to 6400 grams-force. It is recognized that some older test instruments with augmenting weights continue to be used. As a consequence, these older test instruments may be used when agreed upon between the purchaser and the supplier. The conditions for the older units as used with this test method are included in the appendix. For tearing strength above 6400 grams-force, a high-capacity test instrument is available equipped with augmenting weights to increase the capacity.
1.3 This test method is applicable to most nonwoven fabrics that are treated or untreated, including heavily sized, coated, or resin-treated, provided the fabric does not tear in the direction crosswise to the direction of the force applied during the test. If the tear does not occur in the direction of the test, the fabric is considered untearable in that direction by this test method.
1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses may be approximate.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 5734 – 95
Standard Test Method for
Tearing Strength of Nonwoven Fabrics by Falling-Pendulum
(Elmendorf) Apparatus
This standard is issued under the fixed designation D 5734; 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 D 4848 Terminology Relating to and Deformation Proper-
ties of Textiles
1.1 This test method covers the measurement of the average
force required to propagate a single-rip tear starting from a cut
3. Terminology
in a nonwoven fabric using a falling-pendulum (Elmendorf)
3.1 Definitions:
apparatus.
3.1.1 length of tear, n—in tensile testing, the length of
1.2 This standard Elmendorf tear tester with interchange-
fabric torn, as measured on the fabric before tearing.
able pendulums has become the preferred test apparatus for
3.1.2 lengthwise direction, n—in textiles, the direction in a
determining tearing strength up to 6400 grams-force. It is
machine-made fabric parallel to the direction of movement the
recognized that some older test instruments with augmenting
fabric followed in the manufacturing machine.
weights continue to be used. As a consequence, these older test
3.1.2.1 Discussion—For nonwovens, an easily distinguish-
instruments may be used when agreed upon between the
able pattern for orientation may not be apparent, especially if
purchaser and the supplier. The conditions for the older units as
removed from the roll. Care should be taken to maintain the
used with this test method are included in the appendix. For
directionality by clearly marking the direction.
tearing strength above 6400 grams-force, a high-capacity test
3.1.3 nonwoven fabric, n—a textile structure produced by
instrument is available equipped with augmenting weights to
bonding or interlocking of fibers, or both, accomplished by
increase the capacity.
mechanical, chemical, thermal, or solvent means, or combina-
1.3 This test method is applicable to most nonwoven fabrics
tion thereof.
that are treated or untreated, including heavily sized, coated, or
3.1.4 tearing energy, n—in tensile testing of fabrics, the
resin-treated, provided the fabric does not tear in the direction
work done in tearing the specimen.
crosswise to the direction of the force applied during the test.
3.1.5 tearing force, n—the average force required to con-
If the tear does not occur in the direction of the test, the fabric
tinue a tear previously started in a fabric.
is considered untearable in that direction by this test method.
3.1.5.1 Discussion—For nonwovens, the tearing force is
1.4 The values stated in SI units are to be regarded as the
recorded as the maximum force required to continue a tear
standard. The inch-pound units given in parentheses may be
previously started in a fabric.
approximate.
3.1.6 tearing strength, n—the force required either to start
1.5 This standard does not purport to address all of the
or to continue or propagate a tear in a fabric under specified
safety concerns, if any, associated with its use. It is the
conditions.
responsibility of the user of this standard to establish appro-
3.1.7 widthwise direction, n—in textiles, the direction in a
priate safety and health practices and determine the applica-
machine-made fabric perpendicular to the direction of move-
bility of regulatory limitations prior to use.
ment the fabric followed in the manufacturing machine.
2. Referenced Documents 3.1.8 For definitions of other textile terms used in this test
method, refer to Terminologies D 123 and D 4848.
2.1 ASTM Standards:
D 123 Terminology Relating to Textiles and Materials
4. Summary of Test Method
D 689 Test Method for Internal Tearing Resistance of Pa-
3 4.1 The force required to continue a slit previously cut in a
per
2 nonwoven fabric is determined by measuring the work done in
D 1776 Practice for Conditioning Textiles for Testing
tearing it through a fixed distance. The tester consists of a
sector-shaped pendulum carrying a clamp which is in align-
ment with a fixed clamp when the pendulum is in the raised,
starting position with maximum potential energy. The speci-
This test method is under the jurisdiction of ASTM Committee D-13 on Textiles
and is the direct responsibility of Subcommittee D13.64 on Nonwoven Fabric.
men is fastened in the clamps and the tear is started by cutting
Current edition approved June 15, 1995. Published September 1995.
Annual Book of ASTM Standards, Vol 07.01.
Annual Book of ASTM Standards, Vol 15.09.
Annual Book of ASTM Standards, Vol 07.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 5734
a slit in the specimen between the clamps. The pendulum is raised position, means for instantly releasing the pendulum,
then released and the specimen is torn as the moving jaw and means for registering the maximum arc through which the
moves away from the fixed one. The scale attached to the pendulum swings when released, and a graduated scale
pendulum is graduated to read the tearing force of the mounted on the pendulum.
specimen. 6.1.1 The tester may have a pointer mounted on the same
axis as the pendulum that is used to register the tearing force,
5. Significance and Use
or it may be substituted by means of calculating and displaying
the required results without the use of a pointer, such as digital
5.1 This test method for the determination of tearing
display and computer-driven systems. The clamps may prefer-
strength by the pendulum method is used in the trade for the
ably be air actuated, but manual clamping is permitted. The
acceptance testing of commercial shipments of nonwoven
pendulum must have a cutout above the clamp that prevents the
fabrics, but caution is advised since technicians may fail to get
specimen from coming in contact with the sector during the
good agreement between results on certain fabrics. Compara-
test.
tive tests as directed in 5.1.1 may be needed.
6.1.2 The standard test instrument should be equipped with
5.1.1 In case of a dispute arising from differences in
an interchangeable pendulum of the required capacity. Inter-
reported test results when using this test method for acceptance
changeable pendulum models are available in capacities of
testing of commercial shipments, the purchaser and the sup-
1960, 3920, 7840, 15680, 31360, and 62720 mN (200, 400,
plier should conduct comparative test to determine if there is a
800, 1600, 3200, and 6400 gf). The pendulum is equipped with
statistical bias between their laboratories. Statistical assistance
a scale reading directly in percentage of its capacity.
is recommended for the investigation of bias. As a minimum,
6.1.3 The high-capacity instruments have a 62720-mN
the two parties should take a group of test specimens that are
(6400-gf) capacity pendulum with available augmenting
as homogeneous as possible and that are from a lot of material
weights to increase the capacity to 125540, and 250880 mN
of the type in question. The test specimens should then be
(12 800 and 25 600 gf). The tester is equipped with scales
randomly assigned in equal numbers to each laboratory for
reading directly in hectograms (100-gf units) for each capacity.
testing. The average results from the two laboratories should be
See Annex A1.
compared using Students t-test and an acceptable probability
6.2 Calibration Weight, for graduation of 50 % of scale, one
level chosen by the two parties before the testing began. If a
required for each capacity pendulum, or,
bias is found, either its cause must be found and corrected or
6.2.1 Optional, Three-Check-Weight Set, for 20, 50, and
the purchaser and the supplier must agree to interpret future
80 % of scale. Each capacity requires its own set of weights.
test results in the view of the known bias.
When required, calibration weights are available from the
5.2 Compared to other methods for testing tearing strength
manufacturer for high-capacity instruments.
this test method has the advantage of simplicity and speed
since specimens are cut with a die and results are read directly
NOTE 1—While calibration weights are made with scale values of 20,
from the scale on the pendulum. The specimens are relatively
50, and 80 % of scale, it is not absolutely necessary to utilize a complete
small in area and thus, require less fabric. The reading obtained
set. It is acceptable to use one calibration weight which is in the range of
the expected test results, generally 50 % of the scale in use.
is directly proportional to the length of the material torn,
therefore, it is essential that the specimen be prepared to the
6.3 Cutting Die, having essentially the shape and dimen-
exact size specified. For best results, the recommended capac-
sions shown in Fig. 1(a)or1(b). Either die provides the basic
ity of the tester selected is the one where the specimens tear
rectangular test specimen 100 6 2mm(4 6 0.05 in.) long by
between 20 and 80 % of the full-scale value.
63 6 0.15 mm (2.5 6 0.005 in.) wide. The critical dimension
5.3 Instrument models are available with pneumatically
of the test specimen is the distance 43.0 6 0.15 mm (1.69 6
operated clamps and removable pendulums and are recom-
0.005 in.) that is to be torn during the test.
mended for this test. In addition, microprocessor systems for
NOTE 2—The modified die model shown in Fig. 1(a) is typically used
automatic collection of data can provide economical and
for nonwoven fabric testing. The original die model shown in Fig. 1(b)
reliable results when properly calibrated. In any event, the
older units without the deep cut-out in the pendulum that allow
specimen contact with the sector are not recommended.
6. Apparatus
6.1 Falling-Pendulum- (Elmendorf) Type Tester,asde-
scribed in Annex A1 and shown in Fig. A1.1. The tester
includes: a stationary clamp, a movable clamp carried on a
pendulum formed by a sector of a circle that is free to swing on
a bearing, means for leveling, knife mounted on a stationary
post for starting a tear, means for holding the pendulum in a
Elmendorf Tear Testers suitable for use and meet the requirements of this test
NOTE 1—All tolerances 6 0.5 %.
method are available from Thwing-Albert Instrument Co., Philadelphia, PA and
Testing Machines, Inc., Amityville, NY. FIG. 1 Example of Die For Cutting Notched Specimens
D 5734
was that used in woven fabric testing. Either die may be used. These dies
ment of the widthwise direction from different positions along
can be made to order by most die manufacturers.
the length of the fabric with the shorter dimension parallel to
the widthwise direction. When specimens are to be tested wet,
6.4 Air Pressure Regulator, capable of controlling air pres-
cut from areas adjacent to the dry test specimens. Label to
sure between 410 and 620 kPag (60 and 90 psig), when
maintain specimen identity.
applicable, for air clamps.
7.3.2.1 Cut specimens representing a broad distribution
6.5 Setting Gage, for cutting blade that will provide a cut slit
across the width of the laboratory sample and no nearer the
that leaves a 43 6 0.15-mm (1.69 6 0.005-in.) specimen
edge than one tenth its width. Ensure specimens are free of
tearing distance for a 63 6 0.15-mm (2.5 6 0.005-in.) wide
folds, creases, or wrinkles. Avoid getting oil, water, grease, and
specimen, or equivalent.
so forth, on the specimens when handling.
6.6 Jaw Spacing Gage, 2.8 6 0.3-mm (0.125 6 0.012-in.)
width, or equivalent.
8. Preparation of Apparatus and Calibration
6.7 Oil, lightweight, non-gumming clock type.
6.8 Silicone Grease, when applicable, for air clamp lubri-
8.1 For the standard test instrument, select the pendulum
cation.
such that the tear occurs between 20 and 80 % of the full-scale
6.9 Vacuum Cleaner, when applicable, for cleaning dust and
range. Secure the pendulum to the instrument, spacing the
fiber from pendulum scale sensor, or equivalent.
clamps as directed in A2.4.
8.1.1 For the high-capacity test instrument, when required,
7. Sampling and Test Specimens
select the augmenting weight such that the tear occurs between
7.1 Lot Sample—As a lot sample for acceptance testing, 20 and 80 % of the full-scale range. Secure the augmenting
take at random the number of rolls, or pieces, of nonwoven weight to the pendulum.
fabric directed in an applicable material specification or other
8.2 When equipped with a registering sensor, examine the
agreement between the purchaser and the supplier. Consider scale and the complementary black sensor strip along the
the rolls, or pieces, of nonwoven fabric to be the primary
bottom edge of the pendulum. Using care and without touching
sampling units. In the absence of such an agreement, take the the sensor, vacuum away any loose fibers and dust.
number of nonwoven fabric rolls specified in Table 1.
8.3 Examine the knife edge for sharpness, wear, and central
alignment as directed in A2.5-A2.7.
NOTE 3—An adequate specification or other agreement between the
8.4 For air clamps, set the air pressure to the clamps to about
purchaser and the supplier requires taking into account the variability
550 kPag (80 psig).
between rolls or pieces of fabric and between specimens from a swatch
from a roll or pieces of fabric to provide a sampling plan with a 8.4.1 Maximum pressure should be no more than 620 kPag
meaningful producer’s risk, consumer’s risk, acceptable quality level, and
(90 psig) and minimum pressure no less than 410 kPag (60
limiting quality level.
psig).
8.5 When using microprocessor automatic data gathering
7.2 Laboratory Sample—For the laboratory sample, take a
swatch extending the width of the fabric and approximately 1 systems, set the appropriate parameters as defined in the
manufacturer’s instructions.
m (1 yd) along the lengthwise direction from each roll, or
piece, in the lot sample. For rolls of fabric, take a sample that 8.6 Verify the calibration of the selected capacity pendulum
will exclude fabric from the outer wrap of the roll or the inner scale using the one check weight method described in A3.2,
wrap around the core. unless otherwise specified.
7.3 Test Specimens—From each laboratory sampling unit,
8.6.1 The scale may be verified either by the relatively
take five specimens from the lengthwise direction and five simple procedure which uses one Elmendorf check weight, or
specimens from the widthwise direction, for each test condition
alternatively by the three-check-weight procedure, or the
described in 8.1-8.3 as applicable to a material specification or potential energy procedure. The same accuracy and e
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