ASTM_D_2591_-_07_2013.pdf

Designation:D259107(Reapproved 2013)Standard Test Method forLinear Density of Elastomeric Yarns(Short LengthSpecimens)1This standard is issued under the fixed designation D2591;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of 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 lineardensity of short lengths of“as produced”elastomeric yarnsmade from rubber,spandex or other elastomers.NOTE1For the determination of linear density of elastomeric yarnsusing skeins,refer to Test Method D6717.1.2 This test method is not applicable to covered,wrapped,or core-spun yarns,or yarns spun from elastomeric staple,orelastomeric yarns removed from fabrics.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 either SI units or U.S.Customaryunits are to be regarded separately as standard.Within the testthe US Customary units are in parentheses.The values stated ineach system are not exact equivalents;therefore,each systemshall be used independently of the other.1.5 This standard does not purport to address all of thesafety 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:2D123 Terminology Relating to TextilesD2258 Practice for Sampling Yarn for TestingD6717 Test Method for Linear Density of Elastomeric Yarns(Skein Specimens)D4849 Terminology Related to Yarns and Fibers3.Terminology3.1 For all terminology relating to D13.58,Yarns andFibers,refer to Terminology D4849.3.1.1 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 D123.4.Summary of Test Method4.1 A pre-relaxed specimen is fastened in verticallymounted apparatus under a specified tension.Aspecified lengthis cut from the specimen and weighed,and the linear densitycalculated.5.Significance and Use5.1 This test method is considered satisfactory for accep-tance testing of commercial shipments because current esti-mates of between-laboratory 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 bias 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 laboratory.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 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 lthe“as-produced”condition,but may be used for treated elasto-meric yarns provided the treatment is specified.The method1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved July 1,2013.Published September 2013.Originallyapproved in 1967.Last previous edition approved in 2007 as D2591 07.DOI:10.1520/D2591-07R13.2For referenced ASTM standards,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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 does not cover the removal of finish for the determination oflinear density of“finish-free”elastomeric yarns.6.Apparatus36.1 Specimen Boards,with short pile or plush surfaces ofblack or contrasting color,for storing specimens during relax-ation period.6.2 Linear Density Apparatus,mounted vertically on a wallor in a sturdy,stable vertical support and containing theessential parts listed below.See Fig.1 and Annex A1 forgeneral construction details of suitable apparatus.6.2.1 Steel Plate,about 100 mm(4 in.)wide and 1.3 m(1.4yd)long.6.2.2 Clamps,three toggle-action type with rubber tips.6.2.3 Brass Plates,two,with slots at right angles to be usedfor controlling the alignment and length