ASTM D2612-99(2011)
(Test Method)Standard Test Method for Fiber Cohesion in Sliver and Top (Static Tests)
Standard Test Method for Fiber Cohesion in Sliver and Top (Static Tests)
SIGNIFICANCE AND USE
Fiber cohesion is related to the resistance to drafting encountered during textile processing and is affected by such fiber properties as surface lubrication, linear density, surface configuration, fiber length, and crimp.
Fiber cohesion is affected by the alignment of fiber in sliver in addition to the factors listed in 5.1. A half turn of twist in a 140-mm specimen has been found to increase the breaking force by 30 % and a full turn by 60 %. For this reason, care must be exercised in precise mounting of specimens.
For the same reason given in 5.2, card sliver gives a different breaking tenacity than draw sliver of the same fiber. Fibers are more aligned in draw sliver, resulting in lower cohesion.
Increasing the gage length of test specimens reduces the breaking force and apparent cohesion.
The mathematical relationship between the observed value for breaking tenacity and processability has not been established, but the observed values can be used in comparing various fiber characteristics on a relative basis.
This method for measuring fiber cohesion in sliver or top (static tests) is not recommended for acceptance testing because it is an empirical method which must be followed explicitly. Results obtained under other conditions cannot be expected to be comparable.
In some cases, the purchaser and the supplier may have to test a commercial shipment of one or more specific materials by the best available method, even though the method has not been recommended for acceptance testing of commercial shipments. In case of dispute arising from differences in reported test results when using this test method for acceptance testing of commercial shipments, the purchaser and supplier should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens, which are as homogeneous a...
SCOPE
1.1 This test method describes the measurement of fiber cohesion as the force required to cause initial drafting in a bundle of fibers in sliver and top. The observed cohesive force required to separate the fibers is converted to cohesive tenacity based on the linear density of the specimen.
Note 1—For determination of fiber cohesion in dynamic tests, refer to Test Method D4120.
1.2 The values stated in SI units are to be regarded as standard. Inch-pound units appear in parentheses 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.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D2612 − 99 (Reapproved 2011)
Standard Test Method for
Fiber Cohesion in Sliver and Top (Static Tests)
This standard is issued under the fixed designation D2612; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1.1 Discussion—In static tests, cohesive force is mea-
sured while a test specimen is held in fixed position between
1.1 This test method describes the measurement of fiber
two slowly separating clamps. In dynamic tests, cohesive force
cohesion as the force required to cause initial drafting in a
is the force required to maintain drafting in a roving, sliver, or
bundle of fibers in sliver and top. The observed cohesive force
top.
required to separate the fibers is converted to cohesive tenacity
based on the linear density of the specimen. 3.1.2 fiber cohesion, n—theresistancetoseparationoffibers
in contact with one another.
NOTE 1—For determination of fiber cohesion in dynamic tests, refer to
3.1.2.1 Discussion—This resistance is due to the combined
Test Method D4120.
effects of the surface characteristics, length, crimp, finish, and
1.2 The values stated in SI units are to be regarded as
linear density of the fibers. Cohesion should not be confused
standard. Inch-pound units appear in parentheses for informa-
with adhesion or sticking together as in a glutinous substance.
tion only.
3.1.3 For definitions of other terms related to force and
1.3 This standard does not purport to address all of the
deformation in textiles, refer to Terminology D4848. For
safety concerns, if any, associated with its use. It is the
definitions of other textile terms used in this test method, refer
responsibility of the user of this standard to establish appro-
to Terminology D123.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Summary of Test Method
2. Referenced Documents
4.1 The test procedure is based upon the measure of the
2.1 ASTM Standards:
maximum resisting force when a length of sliver or top is
D76 Specification for Tensile Testing Machines for Textiles
pulled in an axial direction. Specified lengths of sliver or top
D123 Terminology Relating to Textiles
are placed in the clamps of a tensile testing machine and the
D1776 Practice for Conditioning and Testing Textiles
maximum force developed during separation of the clamps is
D2258 Practice for Sampling Yarn for Testing
recorded. The cohesive tenacity is calculated in terms of the
D3333 Practice for Sampling Manufactured Staple Fibers,
force per unit linear density of the tested specimen. The
Sliver, or Tow for Testing cohesive tenacity is considered a measure of the cohesion of
D4120 Test Method for Fiber Cohesion in Roving, Sliver,
the fibers in the specimen and is reported in micronewtons/tex
and Top in Dynamic Tests
(gf/denier).
D4848 Terminology Related to Force, Deformation and
Related Properties of Textiles
5. Significance and Use
3. Terminology 5.1 Fiber cohesion is related to the resistance to drafting
encountered during textile processing and is affected by such
3.1 Definitions:
fiber properties as surface lubrication, linear density, surface
3.1.1 cohesive force, n— in sliver and top testing, the force
configuration, fiber length, and crimp.
required to overcome cohesion of a test specimen held in a
fixed position between two slowly separating clamps. 5.2 Fiber cohesion is affected by the alignment of fiber in
sliver in addition to the factors listed in 5.1.Ahalf turn of twist
in a 140-mm specimen has been found to increase the breaking
This test method is under the jurisdiction ofASTM Committee D13 on Textiles
and is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.
force by 30 % and a full turn by 60 %. For this reason, care
Current edition approved Dec. 1, 2011. Published January 2012. Originally
must be exercised in precise mounting of specimens.
approved in 1967. Last previous edition approved in 2005 as D2612–99(2005).
DOI: 10.1520/D2612-99R11.
5.3 For the same reason given in 5.2, card sliver gives a
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
different breaking tenacity than draw sliver of the same fiber.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Fibers are more aligned in draw sliver, resulting in lower
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. cohesion.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2612 − 99 (2011)
5.4 Increasing the gage length of test specimens reduces the 7. Sampling
breaking force and apparent cohesion.
7.1 Lot Sampling—As a lot sample for acceptance testing,
5.5 The mathematical relationship between the observed
take at random the number of shipping containers directed in
value for breaking tenacity and processability has not been the applicable material specification or other agreement be-
established, but the observed values can be used in comparing
tween the purchaser and supplier, such as an agreement to use
various fiber characteristics on a relative basis. Practice D3333 or Practice D2258. Consider shipping contain-
ers to be the primary sampling units.
5.6 This method for measuring fiber cohesion in sliver or
top (static tests) is not recommended for acceptance testing
NOTE 2—An adequate specification or other agreement between the
because it is an empirical method which must be followed purchaser or supplier requires taking into account the variability between
shipping units, between packages, ends or other laboratory sampling unit
explicitly. Results obtained under other conditions cannot be
within a shipping unit if applicable, and within specimens from a single
expected to be comparable.
package, end or other laboratory sampling unit to provide a sampling plan
5.6.1 In some cases, the purchaser and the supplier may
with a meaningful producer’s risk, consumer’s risk, acceptable quality
have to test a commercial shipment of one or more specific
level, and limiting quantity level.
materials by the best available method, even though the
7.2 Laboratory Sample—As a laboratory sample for accep-
method has not been recommended for acceptance testing of
tance testing, take at random from each shipping container in
commercial shipments. In case of dispute arising from differ-
the lot sample the number of laboratory sampling units as
ences in reported test results when using this test method for
directed in an applicable material specification or other agree-
acceptance testing of commercial shipments, the purchaser and
ment between purchaser and supplier such as an agreement to
supplier should conduct comparative tests to determine if there
use Practice D3333 or Practice D2258. Preferably, the same
is a statistical bias between their laboratories. Competent
number of laboratory sampling units are taken from each
statistical assistance is recommended for the investigation of
shipping container in the lot sample. If differing numbers of
bias.As a minimum, the two parties should take a group of test
laboratory sampling units are to be taken from shipping
specimens, which are as homogeneous as possible and which
containers in the lot sample, determine at random which
are from a lot of material of the type in question. Test
shippingcontainersaretohaveeachnumberoflaboratoryunits
specimens then should be randomly assigned in equal numbers
drawn.
to each laboratory for testing.The average results from the two
7.2.1 Eachlaboratorysamplingunitshouldbeatleast100m
laboratories should be compared using appropriate statistical
(100 yd) long.
analysis and a probability level chosen by the two parties prior
7.3 Test Specimens—From each laboratory sampling unit,
to testing. If a bias is found, either its cause must be found and
take one specimen. If the standard deviation determined for the
corrected or the purchaser and the supplier must agree to
laboratory sample is more than a value agreed upon between
interpret future test results with consideration to the known
the purchaser and supplier, continue testing one specimen from
bias.
each unit in the laboratory sample until the standard deviation
6. Apparatus and Material
for all specimens tested is not more than the agreed to value or,
6.1 Tensile Testing Machine, a constant-rate-of-specimen- by agreement, stop testing after a specified number.
extension (CRE) type, conforming to Specification D76, hav-
ing adequate response characteristics to properly record the 8. Preparation of Test Specimens
load-elongation curve of the sliver under test. The capacity of
8.1 Take the test specimens at random from the laboratory
the machine must be selected for the maximum force to fall
sample to be tested. Take care that the specimen is neither
within 50 to 90 % of full scale.
stretched nor distorted.
6.2 Balance, having a capacity of at least 10 g and a
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