1、Designation: D2612 99 (Reapproved 2018)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 l
2、ast 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
3、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.NOTE 1For determination of fiber cohesion in dynamic tests, refer toTest Method D4120.1.2 The values stated in SI units are to be regar
4、ded 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, health, and environmental prac
5、tices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides an
6、d Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2258 Pr
7、actice 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 Defin
8、itions: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 s
9、lowly 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 chara
10、cteristics, 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 text
11、ile 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
12、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 reporte
13、d 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
14、 affected by the alignment of fiber insliver in addition to the factors listed in 5.1. A half turn of twistin a 140-mm specimen has been found to increase the breaking1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58
15、on Yarns and Fibers.Current edition approved Sept. 1, 2018. Published September 2018. Originallyapproved in 1967. Last previous edition approved in 2011 as D261299 (2011).DOI: 10.1520/D2612-99R18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
16、 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 StatesThis international standard was developed in accorda
17、nce with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1force by 30 % and a full turn by 6
18、0 %. 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.5.4 Increasing the gage length of te
19、st 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
20、 for measuring fiber cohesion in sliver ortop (static tests) is not recommended for acceptance testingbecause it is an empirical method which must be followedexplicitly. Results obtained under other conditions cannot beexpected to be comparable.5.6.1 In some cases, the purchaser and the supplier may
21、have to test a commercial shipment of one or more specificmaterials by the best available method, even though themethod has not been recommended for acceptance testing ofcommercial shipments. In case of dispute arising from differ-ences in reported test results when using this test method foraccepta
22、nce testing of commercial shipments, the purchaser andsupplier should conduct comparative tests to determine if thereis a statistical bias between their laboratories. Competentstatistical assistance is recommended for the investigation ofbias. As a minimum, the two parties should take a group of tes
23、tspecimens, which are as homogeneous as possible and whichare from a lot of material of the type in question. Testspecimens then should be randomly assigned in equal numbersto each laboratory for testing. The average results from the twolaboratories should be compared using appropriate statisticalan
24、alysis and a probability level chosen by the two parties priorto testing. If a bias is found, either its cause must be found andcorrected or the purchaser and the supplier must agree tointerpret future test results with consideration to the knownbias.6. Apparatus and Material6.1 Tensile Testing Mach
25、ine, a constant-rate-of-specimen-extension (CRE) type, conforming to Specification D76, hav-ing adequate response characteristics to properly record theload-elongation curve of the sliver under test. The capacity ofthe machine must be selected for the maximum force to fallwithin 50 to 90 % of full s
26、cale.6.2 Balance, having a capacity of at least 10 g and asensitivity of 0.01 g.6.3 Clamps, preferably pneumatically operated, with facesat least 12.5 mm (0.5 in.) wider than the test specimen, in thedimension perpendicular to the direction of load application,and at least 25 mm (1.0 in.) in the dim
27、ension parallel to thedirection of load application.6.4 Mounting TemplateA sheet of paper approximately215 by 280 mm (8.5 by 11 in.), or a longer length when thespecimen length exceeds 280 mm with a 75-mm (3.0 in.)diameter hole cut in the center is used as a mounting board.Two gage reference lines,
28、separated by a distance equal to thedesired specimen length, are drawn across the short dimensionof the paper. The hole is centered between the two referencegage lines.6.5 Tape, cellophane adhesive or masking type, 13-mm(0.5-in.) wide.7. Sampling7.1 Lot SamplingAs a lot sample for acceptance testing
29、,take at random the number of shipping containers directed inthe applicable material specification or other agreement be-tween the purchaser and supplier, such as an agreement to usePractice D3333 or Practice D2258. Consider shipping contain-ers to be the primary sampling units.NOTE 2An adequate spe
30、cification or other agreement between thepurchaser or supplier requires taking into account the variability betweenshipping units, between packages, ends or other laboratory sampling unitwithin a shipping unit if applicable, and within specimens from a singlepackage, end or other laboratory sampling
31、 unit to provide a sampling planwith a meaningful producers risk, consumers risk, acceptable qualitylevel, and limiting quantity level.7.2 Laboratory SampleAs a laboratory sample for accep-tance testing, take at random from each shipping container inthe lot sample the number of laboratory sampling u
32、nits asdirected in an applicable material specification or other agree-ment between purchaser and supplier such as an agreement touse Practice D3333 or Practice D2258. Preferably, the samenumber of laboratory sampling units are taken from eachshipping container in the lot sample. If differing number
33、s oflaboratory sampling units are to be taken from shippingcontainers in the lot sample, determine at random whichshipping containers are to have each number of laboratory unitsdrawn.7.2.1 Each laboratory sampling unit should be at least 100 m(100 yd) long.7.3 Test SpecimensFrom each laboratory samp
34、ling unit,take one specimen. If the standard deviation determined for thelaboratory sample is more than a value agreed upon betweenthe purchaser and supplier, continue testing one specimen fromeach unit in the laboratory sample until the standard deviationfor all specimens tested is not more than th
35、e agreed to value or,by agreement, stop testing after a specified number.8. Preparation of Test Specimens8.1 Take the test specimens at random from the laboratorysample to be tested. Take care that the specimen is neitherstretched nor distorted.8.2 For slivers produced on a short-fiber processing sy
36、stem,such as the cotton system, take specimens having a lengthequal to the nominal staple length plus 4.0 in. (100 mm). Fortop produced on a long-fiber system of processing, such as theworsted system, take specimens having a length equal to thefiber length determined from a fiber sorting, plus 4.0 i
37、n. (100mm).8.2.1 Use the staple length determined by a classer using thehand-stapling technique in the case of cotton, or assigned bythe fiber producer to man-made fibers developed for processingD2612 99 (2018)2on the cotton system. For wool or man-made fibers with greatvariability in their length d
38、istribution and developed forprocess on a long-fiber system, use the fiber length which islonger than 95 % of the fibers in the specimen.8.3 Place the test specimen (sliver or top), approximately 12in. (300 mm) in length or longer when necessary, on the papermount described in 6.4, parallel to the l
39、onger dimension of thepaper mount and across the center of the 3.0-in. (approximately75-mm) diameter hole.8.4 Fasten the test specimen to the paper mount with stripsof adhesive cellophane tape, placed so that the edges of thestrips nearer the hole are aligned with the two marks designat-ing the desi
40、red specimen length. Fasten the test specimen to thepaper mount with as little slack as possible; however, take careto avoid distortion or stretching of specimen. Also, mount thetest specimen with no twist in the sliver. By noting thestriations in the sliver produced by the card or draw frametrumpet
41、, the specimen can be rotated and placed on themounting template without twist.9. Conditioning9.1 Precondition as directed in Practice D1776. Bring thespecimen to moisture equilibrium in the standard atmospherefor testing textiles, which is 70 6 2F (21 6 1C) and 65 62 % relative humidity. Assume tha
42、t moisture equilibrium isreached when two successive weighings made at least 2 h apartdiffer no more than 0.5 % in weight.10. Procedure10.1 Test adequately conditioned specimens in the standardatmosphere for testing textiles.10.2 Set the crosshead gage length of the textile testingmachine 0.5 in. (1
43、2.7 mm) shorter than the test specimenlength (see 8.2) to allow the test specimen to be placed in theclamps with enough slack to prevent stretching. Adjust the rateof crosshead travel of the testing machine to 10 in. (254mm)/min. Adjust the rate of chart travel so that the load-extension curve utili
44、zes a distance of at least 2.0 in. (50 mm)along the extension axis of the chart.10.3 Place the test specimen in the clamps of the testingmachine in such a manner that the innermost edge of one of theadhesive strips holding the test specimen to the paper mount isaligned with the bottom edge of the to
45、p clamp. Align theinnermost edge of the second adhesive strip with the top edgeof the bottom clamp. With a pair of shears, cut across the8.5-in. (215-mm) dimension of the paper mount on a line withthe center of the hole so that the paper mount is completelysevered, leaving only the test specimen sub
46、ject to load appli-cation. Operate the machine to make a load-extension curve ofthe test specimen. From this curve read the cohesive force tothe nearest 0.1 gf from the maximum point of the curve alongthe load axis of the chart.10.4 Remove the broken portions of the test specimen fromthe clamps. Sev
47、er each portion along the innermost edges ofthe adhesive strips and weigh both portions, recording theweight to the nearest 0.01 g.11. Calculation11.1 Calculate the drafting tenacity of individual specimensin milligrams-force per tex (Note 3) using Eq 1 as follows:DT 5 F 3 L/1000 M (1)where:DT = dra
48、fting tenacity, mgf/tex,F = cohesive force, gf,L = specimen length, mm, andM = specimen mass, g.NOTE 3To calculate breaking tenacity in micronewtons per tex(N/tex), multiply milligrams-force per tex (mgf/tex) by 9.81.11.2 Calculate the average cohesive force of all specimensto the nearest 1 mgf/tex.
49、11.3 If requested, calculate the standard deviation or coef-ficient of variation, or both, for each set of test specimens.12. Report12.1 State that the specimens were tested as directed inASTM Test Method D2612. Describe the material(s) or prod-uct(s) sampled and the method of sampling used. Include fibertype, staple length, nominal linear density of the fibers in thesliver or top, crimp of the fibers (if known), and type of sliver(card or draw).12.2 Report the following information:12.2.1 Number of specimens tested,12.2.2 The cohesive force and the drafting tenacity
