ASTM_D_2612_-_99_2011.pdf

Designation:D261299(Reapproved 2011)Standard Test Method forFiber Cohesion in Sliver and Top(Static Tests)1This standard is issued under the fixed designation D2612;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 describes the measurement of fibercohesion as the force required to cause initial drafting in abundle of fibers in sliver and top.The observed cohesive forcerequired to separate the fibers is converted to cohesive tenacitybased on the linear density of the specimen.NOTE1For determination of fiber cohesion in dynamic tests,refer toTest Method D4120.1.2 The values stated in SI units are to be regarded asstandard.Inch-pound units appear in parentheses for informa-tion only.1.3 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:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2258 Practice for Sampling Yarn for TestingD3333 Practice for Sampling Manufactured Staple Fibers,Sliver,or Tow for TestingD4120 Test Method for Fiber Cohesion in Roving,Sliver,and Top in Dynamic TestsD4848 Terminology Related to Force,Deformation andRelated Properties of Textiles3.Terminology3.1 Definitions:3.1.1 cohesive force,n in sliver and top testing,the forcerequired to overcome cohesion of a test specimen held in afixed position between two slowly separating clamps.3.1.1.1 DiscussionIn static tests,cohesive force is mea-sured while a test specimen is held in fixed position betweentwo slowly separating clamps.In dynamic tests,cohesive forceis the force required to maintain drafting in a roving,sliver,ortop.3.1.2 fiber cohesion,nthe resistance to separation of fibersin contact with one another.3.1.2.1 DiscussionThis resistance is due to the combinedeffects of the surface characteristics,length,crimp,finish,andlinear density of the fibers.Cohesion should not be confusedwith adhesion or sticking together as in a glutinous substance.3.1.3 For definitions of other terms related to force anddeformation in textiles,refer to Terminology D4848.Fordefinitions of other textile terms used in this test method,referto Terminology D123.4.Summary of Test Method4.1 The test procedure is based upon the measure of themaximum resisting force when a length of sliver or top ispulled in an axial direction.Specified lengths of sliver or topare placed in the clamps of a tensile testing machine and themaximum force developed during separation of the clamps isrecorded.The cohesive tenacity is calculated in terms of theforce per unit linear density of the tested specimen.Thecohesive tenacity is considered a measure of the cohesion ofthe fibers in the specimen and is reported in micronewtons/tex(gf/denier).5.Significance and Use5.1 Fiber cohesion is related to the resistance to draftingencountered during textile processing and is affected by suchfiber properties as surface lubrication,linear density,surfaceconfiguration,fiber length,and crimp.5.2 Fiber cohesion is affected by the alignment of fiber insliver in addition to the factors listed in 5.1.Ahalf turn of twistin a 140-mm specimen has been found to increase the breakingforce by 30%and a full turn by 60%.For this reason,caremust be exercised in precise mounting of specimens.5.3 For the same reason given in 5.2,card sliver gives adifferent breaking tenacity than draw sliver of the same fiber.Fibers are more aligned in draw sliver,resulting in lowercohesion.1This 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 Dec.1,2011.Published January 2012.Originallyapproved in 1967.Last previous edition approved in 2005 as D261299(2005).DOI:10.1520/D2612-99R11.2For 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 5.4 Increasing the gage length of test specimens reduces thebreaking force and apparent cohesion.5.5 The mathematical relationship between the observedvalue for breaking tenacity and processability has not beenestablished,but the observed values can be used in comparingvarious fiber characteristics on a relative basis.5.6 This method for measuring fiber cohesion in sl