1、Designation: D 6717 07Standard Test Method forLinear Density of Elastomeric Yarns (Skein Specimens)1This standard is issued under the fixed designation D 6717; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the lineardensity of “as produced” elastomeric yarns made from rubber,spandex or ot
3、her elastomers using a skein.NOTE 1For the determination of linear density of elastomeric yarnsusing short length specimens, refer to Test Method D 2591.1.2 The method is not applicable to covered, wrapped, orcore-spun yarns, or yarns spun from elastomeric staple, orelastomeric yarns removed from fa
4、brics.1.3 This test method is applicable to elastomeric yarnshaving a range of 40 to 3200 dtex (36 to 2900 denier).1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafe
5、ty concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to Te
6、xtilesD 1776 Practice for Conditioning and Testing TextilesD 2258 Practice for Sampling Yarn for TestingD 2591 Test Method for Linear Density of ElastomericYarns (Short Length Specimens)D 4849 Terminology Relating to Yarns and Fibers3. Terminology3.1 For all terminology relating to D13.58, Yarns and
7、Fibers, refer to Terminology D 4849.3.1.1 The following terms are relevant to this standard:denier, elastomeric yarn, linear density, tex.3.2 For all other terminology related to textiles, refer toTerminology D 123.4. Summary of Test Method4.1 Aspecimen of specified length is wound into skein formon
8、 a reel. The skein is cut, removed from the reel and weighed.Linear density is calculated using the mass of the skein and thelength of yarn.5. Significance and Use5.1 This test method is considered satisfactory for accep-tance testing of commercial shipments because current esti-mates of between-lab
9、oratory precision are acceptable and themethod is used extensively in the trade for acceptance testing.5.1.1 If there are differences of practical significance be-tween reported test results for two laboratories (or more),comparative tests should be performed to determine if there isa statistical bi
10、as between them, using competent statisticalassistance. As a minimum, use samples for such comparativetests that are as homogeneous as possible, drawn from the samelot of material as the samples that resulted in disparate resultsduring initial testing, and randomly assigned in equal numbersto each l
11、aboratory. The test results from the laboratoriesinvolved should be compared using a statistical test forunpaired data, at a probability level chosen prior to the testingseries. If bias is found, either its cause must be found andcorrected, or future test results for that material must beadjusted in
12、 consideration of the known bias.5.2 Linear density of elastomeric yarns is used in somecalculations for tensile and elastic properties.5.3 The test method is based on elastomeric yarns in theas-produced condition, but may be used for treated elastomericyarns provided the treatment is specified. The
13、 method does notcover the removal of finish for the determination of lineardensity of “finish-free” elastomeric yarns.6. Apparatus6.1 Reel3, 1.125-m (1.230-yd) circumference, with multiplepositions for making several skeins at one time, guides thatapply minimal friction to the running yarn, and with
14、 vertical-mount creel, with automatic counter to set and count thenumber of revolutions. The operating speed may be from 25 to40 rpm; however, 30 rpm is preferred.6.2 Measuring Tape, 6-mm (0.25-in.) wide, steel, accurateto 1 mm (0.05 in.), to verify the reel circumference.1This test method is under
15、the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved Jan. 1, 2007. Published January 2007. Originallyapproved in 2001. Last previous edition approved in 2001 as D 6717 01.2For referenced ASTM standards,
16、 visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3This test apparatus is commercially available.1Copyright ASTM International, 100 Barr Harbo
17、r Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.3 Pads, sheepskin, to prevent yarn from sloughing off thebottom of the package during reeling.6.4 Balance, with an accuracy of 60.1 % of the expectedmass of the specimens. Balance pan should be protected fromdrafts.7. Sampling,
18、Test Specimens, and Test Units7.1 Lot SampleAs a lot sample for acceptance testing,take a random number of shipping units directed in anapplicable material specification or other agreement betweenthe purchaser and the supplier, such as an agreement to usePractice D 2258. Consider shipping cases or o
19、ther shippingunits to be the primary sampling units.NOTE 2An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween shipping units, between packages or ends within a shipping unit,and between specimens from a single package
20、 to provide a sampling witha meaningful producers risk, consumers risk, acceptable quality leveland limiting quality level.7.2 Laboratory SampleAs a laboratory sample for accep-tance testing, take at random from each shipping unit in the lotsample the number of packages directed in an applicablemate
21、rial specification or other agreement between the pur-chaser and the supplier, such as an agreement to use PracticeD 2258. Preferably, take the same number of packages fromeach of the shipping units selected. If differing numbers ofpackages are to be taken from the shipping units, determine atrandom
22、 which shipping units are to have each number ofpackages for testing.7.3 Test SpecimensFrom each package in the laboratorysample, prepare one test specimen from each laboratorysampling unit. Select the skein length using Table 1.8. Conditioning8.1 No preconditioning is required for currently produce
23、drubber and other elastomeric yarns.8.2 Condition the specimens, without tension, on specimenboards in the standard atmosphere for testing textiles asdirected in Practice D 1776 which is 21 6 1C (70 6 2F) and65 6 2 % relative humidity for a minimum of 4 h.9. Preparation of Equipment and Calibration9
24、.1 Periodically confirm the circumference of the reel cir-cumference at each end and the middle as directed in 9.2.9.2 Make one wrap of the measuring tape around the reeland apply tension to the tape by attaching an 0.5 kg (1.0 lb)weight to the end. Read the circumference directly from thetape to th
25、e nearest mm (0.05 in.).9.3 If the circumference at any of the three areas is outsidethe limits of 65 mm (0. 2 in.)., adjust the reel as directed in themanufacturers directions to bring the measurement withinlimits.10. Procedure10.1 Test all specimens in the standard atmosphere fortesting textiles.1
26、0.2 Position the reel bar with the posts in the uppermostand horizontal position10.3 Strip the outer layer of yarn from the package. Placethe package on one of the positions on the creel. Pass the endthrough the reel guide that is aligned with the package positionand then wrap the end of the yarn se
27、veral times about thecorresponding post on the reel bar.10.3.1 For yarns tending to slough from the package, placea pad between the package bottom and the creel spindle base.10.4 Check the reel counter and set it for the number ofrevolutions as directed in Table 1.10.5 Start the reel. There should b
28、e no tension on the yarnother than the mass of the yarn from the package to the firstguide and the natural tension from the guides on the yarn as itis being wound onto the reel.10.6 When the reel stops, manually turn the wheel toposition the bar with the posts in the uppermost position andhorizontal
29、. Check the counter to confirm the number ofrevolutions made.10.7 Cut the skein immediately below the post bar andremove it from the reel.10.8 Weigh the skein and record the mass (M) to the nearest0.001 g. Record the mass.10.9 Continue as directed in 10.1-10.8 until all the requiredspecimens for the
30、 lot have been tested.11. Calculation or Interpretation of Results11.1 Length of Yarn SpecimenCalculate the length of theyarn specimen by multiplying the number of reel wraps timesthe wheel circumference to the nearest mm (0.05 in.).11.2 Linear DensityCalculate the linear density for eachspecimen to
31、 the nearest 0.1 dtex (0.1 denier), using Eq 1 or Eq2.T 5 10000 3 M/L (1)D 5 9000 3 M/L (2)TABLE 1 Suggested Skein RevolutionsLinear Density Number of RevolutionsAdtex denier11 10 160044 40 40077 70 250155 140 110310 280 65465 420 40930 840 251865 1680 162490 2240 8AThe number of revolutions in a sk
32、ein should give a mass between 2 and 3 g;however, skeins weighing as low as 1 g may be used, for yarns in the lower lineardensity ranges.TABLE 2 Skein Denier, Average Percent and Components ofVariation expressed as Squares of Standard DeviationNOTEResponse = Skein Denier.Material Average V(Lab) V(We
33、ek, Lab) V(Date, Week, Lab)1 40.55625 0.02476 0.01761 0.027282 40.78500 0.00000 0.21737 0.022863 40.71813 0.00704 0.24014 0.044784 40.67063 0.00000 0.20040 0.01254D6717072where:T = linear density, dtex,D = linear density, denier,M = mass of specimen, g, (from 10.8), andL = length of specimen, m, (fr
34、om 11.1).NOTE 3If inch-pound units are used, divide the length of the yarn ininches by 39.37 to obtain m.11.3 Calculate the average linear density for the lot.11.4 If requested, calculate the coefficient of variation,standard deviation.12. Report12.1 State that the samples were tested as directed in
35、 TestMethod D 6717. Describe the material or product sampled andthe method of sampling used.12.2 Report the following information for the lot:12.2.1 Linear density for each specimen,12.2.2 Coefficient of variation, or standard deviation, orboth, if calculated,12.2.3 Any modification to the method.13
36、. Precision and Bias13.1 An interlaboratory study was performed in 1997 toestimate variability of the test method. The study included twolaboratories. Eight cakes of 40 denier elastomeric yarn pro-duced under the same conditions were used in the test. Fourcakes were distributed to each laboratory. T
37、hese four cakestested 2 times per week for five weeks. One specimen per cakewas tested on each test date. ANOVA was used to determinevariance components.13.2 Method repeatability is defined as the “maximumdifference” that can “reasonably” be expected between two testresults obtained on the same mate
38、rial when the test results areobtained in the same laboratory. Repeatability standard devia-tion, sr, is taken to be the square root of the “specimen”variance component, and represents within-operator precision.Since only one specimen per cake is used in this method, srandmethod repeatability for th
39、is test are equal to zero. Methodreproducibility is defined as the “maximum difference” that can“reasonably” be expected between two test results obtained onthe same material when the test results are obtained fromdifferent laboratories.4sR, the total standard deviation, isformed by taking the squar
40、e root of the sum of intra- andinter-laboratory variance components.NOTE 4Because the interlaboratory test included less than the recom-mended five laboratories, estimates of precision data in Tables 1 and 2may be either underestimated or overestimated to a considerable extentand should be used with
41、 special caution.13.3 BiasThe procedure of this test method produces atest value that can be defined only in terms of a test method.There is no independent, referee method by which bias may bedetermined. This test method has no known bias.14. Keywords14.1 elastomeric yarn; linear densityASTM Interna
42、tional takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely th
43、eir own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should
44、 be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standa
45、rds, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).4John Mandel and Theodore W. Lashof, 1987. The Nature of Repeatability andReproducibility. Jour., Quality Technology, pg. 19, Vol 1.D6717073
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