ASTM D3937-2012 Standard Test Method for Crimp Frequency of Manufactured Staple Fibers 《人造短纤维卷曲率的标准试验方法》.pdf

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1、Designation:D393707 Designation: D3937 12Standard Test Method forCrimp Frequency of mManufactured Staple Fibers1This standard is issued under the fixed designation D3937; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of

2、last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the crimp frequency of manufactured staple fibers. This test method isapp

3、licable 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 modifycrimp in fiber. Hence, the value for crimp of fibers taken f

4、rom spun yarns may be different than that of the same fiber prior to themanufacturing or treatment processes.1.2 Three options are provided for preparation of the specimens. Option One (preferred) uses single fibers for the specimenswith a low magnification available, Option Two (optional for staple

5、 or tow samples) uses fiber chips as the specimens, and OptionThree 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 safet

6、y concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to Textile

7、sD1776 Practice for Conditioning and Testing TextilesD2258 Practice for Sampling Yarn for TestingD3333 Practice for Sampling Manufactured Staple Fibers, Sliver, or Tow for TestingD4849 Terminology Related to Yarns and Fibers3. Terminology3.1 For all terminology relating to D13.58, Yarns and Fibers,

8、refer to Terminology D4849.3.1.1 The following terms are relevant to this standard: crimp. crimp frequency, crimp index, fiber chip.3.2 For all other terms are related to textiles, refer to Terminology D123.4. Summary of Test Method4.1 For Option One, a fiber specimen of manufactured staple is place

9、d on a short pile or plush surface. The crimps along theentire length of the specimen is counted. After the specimen is counted, the fiber is straightened without deformation and itsuncrimped length measured. Crimp frequency is reported as the number of crimps per unit of extended length.4.2 For Opt

10、ion Two, the number of crimps is counted in fiber chip specimens. The specimen length is measured on fibers takenfrom each of the chips.4.3 For Option Three, the fiber specimen is mounted between microscope slides. The image of the specimen is projected andits crimp is counted. The extended length o

11、f the specimen is measured as in Option One.4.4 In each option, the crimp frequency is calculated from the numbers of crimp counted and the fiber lengths measured.5. Significance and Use5.1 This test method for the determination of crimp frequency of manufactured staple fibers may be used for the ac

12、ceptancetesting of commercial shipments but caution is advised since between-laboratory precision is known to be poor. Comparative testsconducted as directed in 5.1.1 may be advisable.1This test method is under the jurisdiction of ASTM Committee D13 on Textiles and is the direct responsibility of Su

13、bcommittee D13.58 on Yarns and Fibers.Current edition approved Jan.Feb. 1, 2007.2012. Published January 2007.February 2012. Originally approved in 1980. Last previous edition approved in 20012007 asD3937 017. DOI: 10.1520/D3937-07.10.1520/D3937-12.2For referenced ASTM standards, visit the ASTM websi

14、te, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indicati

15、on of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be consi

16、dered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.1 If there are differences or practical significance between reported test results for two laboratories (or more), comparativetests should be performed to

17、 determine if there is a statistical bias between them, using competent statistical assistance. As aminimum, test samples that are as homogeneous as possible, drawn from the material from which the disparate test results wereobtained, and randomly assigned in equal numbers to each laboratory for tes

18、ting. The test results from the two laboratories shouldbe compared using a statistical test for unpaired data, at a probability level chosen prior to testing series. If a bias is found, eitherits cause must be found and corrected, or future test results for that material must be adjusted in consider

19、ation 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 majordifferences in crimp frequency. This test method is not considered to be useful in research and development where minordifferences or more compl

20、ete 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 visua

21、l appearance of thefinished textile product.6. Apparatus6.1 Short Pile or Plush Surface, of a color contrasting with color of fibers under investigation.6.2 Magnifier, with no greater than 103 magnification, optional for counting crimp of fibers of low linear density in Option Oneor in measuring len

22、gths.6.3 For Option Three:6.3.1 Projector, capable of a magnification of 103.6.3.2 Microscope Slides, 25 by 75 mm (1 by 3 in.).6.4 Specimen Board, covered with a short pile or plush.6.5 Tweezers, two pair.6.6 Scale, graduated in millimetres or116-in. units.7. Sampling7.1 Lot samplingAs a lot sample

23、for acceptance testing, take at random the number of shipping containers directed in theapplicable material specification or other agreement between the purchaser and the supplier, such as an agreement to use PracticeD3333 or Practice D2258. Consider shipping containers to be the primary sampling un

24、its.NOTE 1An adequate specification or other agreement between the purchaser or the supplier requires taking into account the variability betweenshipping units, between packages, ends, or other laboratory sampling unit within a shipping unit if applicable, and within specimens from a singlepackage,

25、end or other laboratory sampling unit to provide a sampling plan with a meaningful producers risk, consumers risk, acceptable quality level,and limiting quantity level.7.2 Laboratory SampleAs a laboratory sample for acceptance testing, take at random from each shipping container in the lotsample the

26、 number of laboratory sampling units as directed in an applicable material specification or other agreement between thepurchaser and the supplier such as an agreement to use Practice D3333 or Practice D2258. Preferably, the same number oflaboratory sampling units are taken from each shipping contain

27、er in the lot sample. If differing numbers of laboratory samplingunits are to be taken from shipping containers in the lot sample, determine at random which shipping containers are to have eachnumber of laboratory units drawn.7.2.1 For Staple FiberTake 50-g samples from laboratory sampling units.7.2

28、.2 For Sliver (or Top) or TowTake 1 m from the leading end which has a clean, uniform appearance.7.3 Test SpecimensFrom each laboratory sampling unit, take twenty-five specimens at random. For Options One and Three,each specimen is a fiber, and for Option Two, the specimen is a fiber chip. If the st

29、andard deviation determined for the tenspecimens is more than a value agreed upon between the purchaser and the supplier, continue testing in groups of ten specimensfrom the same laboratory sampling unit until the standard deviation for all specimens tested is not more than the agreed to valueor, by

30、 agreement, stop testing after a specified number.8. Conditioning8.1 Condition the specimens as directed in Practice D1776.9. Procedure9.1Test conditioned specimens in the standard atmosphere for testing textiles, which is 21 6 1C (70 6 2F) and 65 6 2%relative humidity.9.1 Test conditioned specimens

31、 in the standard atmosphere as directed in Practice D1776.9.2 Specimen Preparation Options:9.2.1 Option One Single Fiber (Preferred)Carefully remove 25 fibers at random from each laboratory sampling unit, usingtweezers. Place these specimens on a specimen board. Using fingertip pressure, flatten eac

32、h specimen with the crimp in a planeparallel with the board. Take care not to destroy the crimp.9.2.2 Option Two Fiber ChipCarefully remove 25 fiber chips at random from each laboratory sampling unit using tweezers.Place these specimens on a specimen board and flatten with fingertip pressure as in 9

33、.2.1. Take care not to destroy the crimp.D3937 1229.2.3 Option Three Fiber ProjectionCarefully remove 25 fiber at random from each laboratory sampling unit, using tweezers.Place these specimens on microscope slides without disturbing the crimp. Place the prepared slide on the stage of the projector.

34、Project the image onto a smooth white surface.9.3 Counting Crimp:9.3.1 For all options, count and record the number of crimp units along the entire length of the specimen (see Fig. 1). Note anygross differences observed in crimp distribution or evenness.9.3.2 Where possible count the crimp in at lea

35、st 50 mm (2 in.). If fibers are longer than 50 mm, they may be cut to approximately50-mm lengths before counting the crimp.NOTE 2Low-power magnification, no greater than 103, may be useful in counting the number of crimp units.NOTE 3Users of this test method should be aware of the fact that crimp co

36、nfiguration in a manufactured fiber is not always uniform over the lengthof the fiber.9.4 Measuring Fiber Length:9.4.1 For all options, hold one end of the fiber with a finger of one hand and gently straighten the fiber with the other hand.Be careful not to stretch the fiber. If Option 2 is used, re

37、move a fiber from each chip, place these fibers on a specimen board andmeasure the lengths as being representative of the chips. If Option 3 is used, transfer fiber from the slide to the pile or plush surfaceto measure the extended length. Do not measure the projected image.9.4.2 For all options, pl

38、ace the scale on the specimen board. Grip one end of a fiber near the tip with tweezers and hold the tipof the fiber aligned with the zero on the scale. Then, grip the other end of the fiber near its tip with a second pair of tweezers andgently straighten the fiber along the scale. Be careful not to

39、 stretch the fiber.9.4.2.1 From the scale, read the extended specimen length to the nearest 1 mm (116 in.).9.5 Continue counting and measuring as directed in 9.3 and 9.4 to test the remaining specimens.10. Calculation10.1 Calculate the crimp frequency of each specimen to the nearest 0.1 crimp per 25

40、 mm (crimp per inch), using Eq 1 or Eq2:F5C325/L (1)F 525 CL(1)F5C/L (2)F 5CL(2)where:F = crimp frequency, crimp/25 mm (crimp/1 in.),C = number of crimps counted, andL = extended length of the crimp-counted segment, mm (in.).10.2 Calculate the average crimp frequency for each laboratory sampling uni

41、t and for the lot.10.3 If requested, calculate the standard deviation or coefficient of variation, or both, for each laboratory sampling unit and forthe lot sample container and the lot.FIG. 1 Standard Reference Chart for Crimp CountingD3937 12311. Report11.1 State that the specimens were tested as

42、directed in Test Method D3937 for crimp frequency. Describe the material orproduct sampled and the method of sampling used.11.2 Report the following information:11.2.1 Average crimp frequency for each lot sample container tested and for each laboratory sampling unit and for the lot.11.2.2 Any gross

43、differences in crimp configuration uniformity observed,11.2.3 Standard deviation or coefficient of variation, or both, for the lot sample container and for each laboratory sampling unitand for the lot, if calculated.11.2.4 The specimen preparation option used, and11.2.5 Magnification, if used.12. Pr

44、ecision and Bias12.1 SummaryIn comparing two averages of 25 observations, the differences should not exceed 1.15 crimps per inch in 95out of 100 cases when all of the observations are taken by the same well-trained operator using the same piece of test equipmentand specimens randomly drawn from the

45、sample of material. Larger differences are likely to occur under all other circumstances.12.2 Interlaboratory Test DataAn interlaboratory test was run in 1980 in which randomly drawn samples of five materialswere tested in each of six laboratories. Each laboratory used two operators, each of whom te

46、sted 25 specimens of each material.The components of variance for crimps per unit length results expressed as standard deviations were calculated to be as follows:Crimps per InchSingle-material comparisons:Single-operator component 2.07Within-laboratory component 0.49Between-laboratory component 1.9

47、0Multi-material comparisons:Single-operator component 0.78Within-laboratory component 0.49Between-laboratory component 2.35NOTE 4Where separate components of variance are shown for multi-material comparisons, (1) the multi-material, single-operator component is dueto an operator times material (with

48、in-laboratories) interaction and is combined with the single-material, single-operator component in calculating criticaldifferences, and (2) any increase in the multi-material, between-laboratory component over the single-material, between-operator component is due to amaterial times laboratory inte

49、raction.12.3 PrecisionFor the components of variance reported in 12.2, two averages of observed values should be consideredsignificantly different at the 95 % probability level if the difference equals or exceeds critical differences as shown in Table 1.NOTE 5The tabulated values of the critical differences should be considered to be a general statement. Particularly with respect to between-laboratoryprecision. Before a meaningful statement can be made about two specific laboratories, the amount of statistical bias, if any, between them must beestablished,