ASTM D3937-12(2018)
(Test Method)Standard Test Method for Crimp Frequency of Manufactured Staple Fibers
Standard Test Method for Crimp Frequency of Manufactured Staple Fibers
SIGNIFICANCE AND USE
5.1 This test method for the determination of crimp frequency of manufactured staple fibers may be used for the acceptance testing of commercial shipments but caution is advised since between-laboratory precision is known to be poor. Comparative tests conducted as directed in 5.1.1 may be advisable.
5.1.1 If there are differences or practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, test samples that are as homogeneous as possible, drawn from the material from which the disparate test results were obtained, and randomly assigned in equal numbers to each laboratory for testing. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to testing series. If a bias is found, either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.
5.2 This test method is used for quality control. It is an unsophisticated procedure which is particularly useful in detecting major differences in crimp frequency. This test method is not considered to be useful in research and development where minor differences or more complete crimp characterization, including amplitude and index, may be necessary.
5.3 Crimp in fiber affects the carding and subsequent processing of the fiber into either a yarn or a nonwoven fabric.
5.4 Staple crimp in fiber will also affect the bulk or openness of a yarn and therefore the hand and visual appearance of the finished textile product.
SCOPE
1.1 This test method covers the determination of the crimp frequency of manufactured staple fibers. This test method is applicable to all crimped staple fibers provided the crimp can be viewed two-dimensionally as a sine-wave configuration.
1.1.1 It should be recognized that yarn manufacturing processes or treatments to manufactured yarns can influence or modify crimp in fiber. Hence, the value for crimp of fibers taken from spun yarns may be different than that of the same fiber prior to the manufacturing or treatment processes.
1.2 Three options are provided for preparation of the specimens. Option One (preferred) uses single fibers for the specimens with a low magnification available, Option Two (optional for staple or tow samples) uses fiber chips as the specimens, and Option Three uses projected images of single fibers.
1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units in parentheses are 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3937 − 12 (Reapproved 2018)
Standard Test Method for
Crimp Frequency of Manufactured Staple Fibers
This standard is issued under the fixed designation D3937; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D2258Practice for Sampling Yarn for Testing
D3333Practice for Sampling Manufactured Staple Fibers,
1.1 This test method covers the determination of the crimp
Sliver, or Tow for Testing
frequency of manufactured staple fibers. This test method is
D4849Terminology Related to Yarns and Fibers
applicable to all crimped staple fibers provided the crimp can
be viewed two-dimensionally as a sine-wave configuration.
3. Terminology
1.1.1 It should be recognized that yarn manufacturing pro-
3.1 For all terminology relating to D13.58, Yarns and
cesses or treatments to manufactured yarns can influence or
Fibers, refer to Terminology D4849.
modify crimp in fiber. Hence, the value for crimp of fibers
3.1.1 The following terms are relevant to this standard:
taken from spun yarns may be different than that of the same
crimp, crimp frequency, crimp index, fiber chip.
fiber prior to the manufacturing or treatment processes.
3.2 For all other terms are related to textiles, refer to
1.2 Three options are provided for preparation of the speci-
Terminology D123.
mens. Option One (preferred) uses single fibers for the speci-
menswithalowmagnificationavailable,OptionTwo(optional
4. Summary of Test Method
for staple or tow samples) uses fiber chips as the specimens,
4.1 For Option One, a fiber specimen of manufactured
and Option Three uses projected images of single fibers.
staple is placed on a short pile or plush surface. The crimps
1.3 The values stated in SI units are to be regarded as the
along the entire length of the specimen is counted. After the
standard.The inch-pound units in parentheses are for informa-
specimen is counted, the fiber is straightened without defor-
tion only.
mationanditsuncrimpedlengthmeasured.Crimpfrequencyis
1.4 This standard does not purport to address all of the reported as the number of crimps per unit of extended length.
safety concerns, if any, associated with its use. It is the
4.2 For Option Two, the number of crimps is counted in
responsibility of the user of this standard to establish appro-
fiber chip specimens. The specimen length is measured on
priate safety, health, and environmental practices and deter-
fibers taken from each of the chips.
mine the applicability of regulatory limitations prior to use.
4.3 For Option Three, the fiber specimen is mounted be-
1.5 This international standard was developed in accor-
tween microscope slides. The image of the specimen is
dance with internationally recognized principles on standard-
projected and its crimp is counted. The extended length of the
ization established in the Decision on Principles for the
specimen is measured as in Option One.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 4.4 In each option, the crimp frequency is calculated from
Barriers to Trade (TBT) Committee.
the numbers of crimp counted and the fiber lengths measured.
5. Significance and Use
2. Referenced Documents
5.1 This test method for the determination of crimp fre-
2.1 ASTM Standards:
quency of manufactured staple fibers may be used for the
D123Terminology Relating to Textiles
acceptance testing of commercial shipments but caution is
D1776Practice for Conditioning and Testing Textiles
advised since between-laboratory precision is known to be
poor. Comparative tests conducted as directed in 5.1.1 may be
ThistestmethodisunderthejurisdictionofASTMCommitteeD13onTextiles
advisable.
and is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.
5.1.1 If there are differences or practical significance be-
Current edition approved July 1, 2018. Published August 2018. Originally
tween reported test results for two laboratories (or more),
approved in 1980. Last previous edition approved in 2007 as D3937–07(2012).
DOI: 10.1520/D3937-12R18.
comparative tests should be performed to determine if there is
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
a statistical bias between them, using competent statistical
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
assistance. As a minimum, test samples that are as homoge-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. neous as possible, drawn from the material from which the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3937 − 12 (2018)
disparate test results were obtained, and randomly assigned in from shipping containers in the lot sample, determine at
equal numbers to each laboratory for testing. The test results random which shipping containers are to have each number of
from the two laboratories should be compared using a statis- laboratory units drawn.
tical test for unpaired data, at a probability level chosen prior 7.2.1 For Staple Fiber—Take 50-g samples from laboratory
to testing series. If a bias is found, either its cause must be sampling units.
foundandcorrected,orfuturetestresultsforthatmaterialmust 7.2.2 For Sliver (or Top) or Tow—Take 1 m from the
be adjusted in consideration of the known bias. leading end which has a clean, uniform appearance.
5.2 This test method is used for quality control. It is an 7.3 Test Specimens—From each laboratory sampling unit,
unsophisticated procedure which is particularly useful in de- take twenty-five specimens at random. For Options One and
tecting major differences in crimp frequency. This test method Three, each specimen is a fiber, and for Option Two, the
is not considered to be useful in research and development specimen is a fiber chip. If the standard deviation determined
where minor differences or more complete crimp for the ten specimens is more than a value agreed upon
characterization, including amplitude and index, may be nec- between the purchaser and the supplier, continue testing in
groups of ten specimens from the same laboratory sampling
essary.
unit until the standard deviation for all specimens tested is not
5.3 Crimp in fiber affects the carding and subsequent
more than the agreed to value or, by agreement, stop testing
processing of the fiber into either a yarn or a nonwoven fabric.
after a specified number.
5.4 Staple crimp in fiber will also affect the bulk or
8. Conditioning
openness of a yarn and therefore the hand and visual appear-
ance of the finished textile product.
8.1 Condition the specimens as directed in Practice D1776.
9. Procedure
6. Apparatus
9.1 Test conditioned specimens in the standard atmosphere
6.1 Short Pile or Plush Surface, of a color contrasting with
as directed in Practice D1776.
color of fibers under investigation.
9.2 Specimen Preparation Options:
6.2 Magnifier, with no greater than 10× magnification,
9.2.1 Option One Single Fiber (Preferred)—Carefully re-
optional for counting crimp of fibers of low linear density in
move 25 fibers at random from each laboratory sampling unit,
Option One or in measuring lengths.
using tweezers. Place these specimens on a specimen board.
6.3 For Option Three:
Using fingertip pressure, flatten each specimen with the crimp
6.3.1 Projector, capable of a magnification of 10×.
in a plane parallel with the board. Take care not to destroy the
6.3.2 Microscope Slides, 25 by 75 mm (1 by 3 in.).
crimp.
6.4 Specimen Board, covered with a short pile or plush.
9.2.2 Option Two Fiber Chip—Carefully remove 25 fiber
chips at random from each laboratory sampling unit using
6.5 Tweezers, two pair.
tweezers. Place these specimens on a specimen board and
6.6 Scale, graduated in millimetres or ⁄16-in. units.
flatten with fingertip pressure as in 9.2.1. Take care not to
destroy the crimp.
7. Sampling
9.2.3 Option Three Fiber Projection—Carefully remove 25
7.1 Lot sampling—As a lot sample for acceptance testing,
fiber at random from each laboratory sampling unit, using
take at random the number of shipping containers directed in
tweezers. Place these specimens on microscope slides without
the applica
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