1、Designation: D2612 99 (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 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 and health practices and determ
5、ine 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 TestingD33
6、33 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 slive
7、r 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 tes
8、ts, cohesive forceis the force required to maintain drafting in a roving, sliver, ortop.3.1.2 fiber cohesion, nthe resistance to separation offibers in contact with one another.3.1.2.1 DiscussionThis resistance is due to the combinedeffects of the surface characteristics, length, crimp, finish, andl
9、inear 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, ref
10、erto 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 de
11、veloped 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. Sig
12、nificance 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 ins
13、liver in addition to the factors listed in 5.1. A half 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 adiff
14、erent 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 test specimens reduces thebreaking force and apparent cohesion.1This test method is under the jurisdiction of ASTM Committee D13 on Textiles
15、and 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 websi
16、te, 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United State
17、s.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 sliver ortop (static tests
18、) 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 mayhave to test a commercial shipment of one or more specificm
19、aterials 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 foracceptance testing of commercial shipments, the purchaser andsuppl
20、ier 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 testspecimens, which are as homogeneous as possible and whicha
21、re 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 statisticalanalysis and a probability level chosen by the two parties pr
22、iorto 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 Machine, a constant-rate-of-specimen-extension (CRE) type, conf
23、orming 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 scale.6.2 Balance, having a capacity of at least 10 g and as
24、ensitivity 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 dimension parallel to thedirection of load application.6.4 Mou
25、nting 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, separated by a distance equal to thedesired specimen length
26、, 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,take at random the number of shipping containers directed
27、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 specification or other agreement between thepurchaser or suppl
28、ier 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 unit to provide a sampling planwith a meaningful producers
29、 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 units asdirected in an applicable material specification or
30、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 numbers oflaboratory sampling units are to be taken from shipping
31、containers 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 sampling unit,take one specimen. If the standard deviation dete
32、rmined 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 the agreed to value or,by agreement, stop testing after a spe
33、cified 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 system,such as the cotton system, take specimens having a len
34、gthequal 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 in. (100mm).8.2.1 Use the staple length determined by a clas
35、ser using thehand-stapling technique in the case of cotton, or assigned bythe fiber producer to man-made fibers developed for processingon the cotton system. For wool or man-made fibers with greatvariability in their length distribution and developed forprocess on a long-fiber system, use the fiber
36、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 longer dimension of thepaper mount and across the center of the 3.0-in. (app
37、roximately75-mm) diameter hole.8.4 Fasten the test specimen to the paper mount with stripsof adhesive cellophane tape, placed so that the edges of theD2612 99 (2011)2strips nearer the hole are aligned with the two marks designat-ing the desired specimen length. Fasten the test specimen to thepaper m
38、ount 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, the specimen can be rotated and placed on themounting tem
39、plate 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 that moisture equilibrium isreached when two successive weighi
40、ngs 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. (12.7 mm) shorter than the test specimenlength (see 8.2) to a
41、llow 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 utilizes a distance of at least 2.0 in. (50 mm)along the extensi
42、on 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 top clamp. Align theinnermost edge of the second adhesive str
43、ip 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 subject to load appli-cation. Operate the machine to make a lo
44、ad-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. Sever each portion along the innermost edges ofthe adhesive st
45、rips 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 = drafting tenacity, mgf/tex,F = cohesive force, gf,L = specimen
46、 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.11.3 If requested, calculate the standard deviation or coef
47、-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 fi
48、bers 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 for eachlaboratory sampling unit and for the lot, and12.2.3 Coefficient of variation
49、for each set of test speci-mens, if calculated.12.2.4 Any modification to the test.13. Precision and Bias13.1 Test DataNo recent interlaboratory test has beenconducted using this method. A test was run on two materialsby one operator. The components of variance, expressed ascoefficients of variation, are given in Table 1.13.2 PrecisionFor the components of variance listed inTable 2, two averages of observed values should be consideredsignificantly different at the 90 % probability level if thedifference equals or exceeds the critical differences given inTable 3.NOTE
