ASTM D3937-07
(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
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.
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.
Crimp in fiber affects the carding and subsequent processing of the fiber into either a yarn or a nonwoven fabric.
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 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.
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)
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Designation:D3937–07
Standard Test Method for
1
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. 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 The following terms are relevant to this standard:
crimp. crimp frequency, crimp index, fiber chip.
1.1 This test method covers the determination of the crimp
3.2 For all other terms are related to textiles, refer to
frequency of manufactured staple fibers. This test method is
Terminology D123.
applicable to all crimped provided the crimp can be viewed
two-dimensionally as a sine-wave configuration.
4. Summary of Test Method
1.1.1 It should be recognized that yarn manufacturing pro-
4.1 For Option One, a fiber specimen of manufactured
cesses or treatments to manufactured yarns can influence or
staple is placed on a short pile or plush surface. The crimps
modify crimp in fiber. Hence, the value for crimp of fibers
along the entire length of the specimen is counted. After the
taken from spun yarns may be different than that of the same
specimen is counted, the fiber is straightened without defor-
fiber prior to the manufacturing or treatment processes.
mation and its uncrimped length measured. Crimp frequency is
1.2 Three options are provided for preparation of the speci-
reported as the number of crimps per unit of extended length.
mens. Option One (preferred) uses single fibers for the speci-
4.2 For Option Two, the number of crimps is counted in
menswithalowmagnificationavailable,OptionTwo(optional
fiber chip specimens. The specimen length is measured on
for staple or tow samples) uses fiber chips as the specimens,
fibers taken from each of the chips.
and Option Three uses projected images of single fibers.
4.3 For Option Three, the fiber specimen is mounted be-
1.3 The values stated in SI units are to be regarded as the
tween microscope slides. The image of the specimen is
standard. The inch-pound units in parentheses are for informa-
projected and its crimp is counted. The extended length of the
tion only.
specimen is measured as in Option One.
1.4 This standard does not purport to address all of the
4.4 In each option, the crimp frequency is calculated from
safety concerns, if any, associated with its use. It is the
the numbers of crimp counted and the fiber lengths measured.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Significance and Use
bility of regulatory limitations prior to use.
5.1 This test method for the determination of crimp fre-
quency of manufactured staple fibers may be used for the
2. Referenced Documents
2 acceptance testing of commercial shipments but caution is
2.1 ASTM Standards:
advised since between-laboratory precision is known to be
D123 Terminology Relating to Textiles
poor. Comparative tests conducted as directed in 5.1.1 may be
D1776 Practice for Conditioning and Testing Textiles
advisable.
D2258 Practice for Sampling Yarn for Testing
5.1.1 If there are differences or practical significance be-
D3333 Practice for Sampling Manufactured Staple Fibers,
tween reported test results for two laboratories (or more),
Sliver, or Tow for Testing
comparative tests should be performed to determine if there is
D4849 Terminology Related to Yarns and Fibers
a statistical bias between them, using competent statistical
3. Terminology assistance. As a minimum, test samples that are as homoge-
neous as possible, drawn from the material from which the
3.1 For all terminology relating to D13.58, Yarns and
disparate test results were obtained, and randomly assigned in
Fibers, refer to Terminology D4849.
equal numbers to each laboratory for testing. The test results
from the two laboratories should be compared using a statis-
1
This test method is under the jurisdiction ofASTM Committee D13 onTextiles
tical test for unpaired data, at a probability level chosen prior
and is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.
to testing series. If a bias is found, either its cause must be
Current edition approved Jan. 1, 2007. Published January 2007. Originally
foundandcorrected,orfuturetestresultsforthatmaterialmust
approved in 1980. Last previous edition approved in 2001 as D3937 – 01. DOI:
10.1520/D3937-07.
be adjusted in consideration of the known bias.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.2 This test method is used for quality control. It is an
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
unsophisticated procedure which is part
...
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