1、Designation: D4120 07 (Reapproved 2018)Standard Test Method forFiber Cohesion in Roving, Sliver, and Top in Dynamic Tests1This standard is issued under the fixed designation D4120; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 dynamic cohesive force required to mainta
3、indrafting in rovings, slivers or tops when they are subjected tostress induced by passing between pairs of drafting rolls ofdifferent surface speeds. The cohesive force is converted tocohesive tenacity based on the linear density of the material.NOTE 1For static tests refer to Test Method D2612.1.2
4、 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 practices and deter-mine the applicability of regulatory limitations prior to use.1.
5、3 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 and Recom-mendations issued by the World Trade Organization TechnicalBarriers to T
6、rade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD519 Test Method for Length of Fiber in Wool TopD1440 Test Method for Length and Length Distribution ofCotton Fibers (Array Method)D1447 Test Method for Length and Length Uniformity ofCotton Fibers b
7、y Photoelectric MeasurementD1575 Test Method for Fiber Length of Wool in ScouredWool and in Card SliverD1776 Practice for Conditioning and Testing TextilesD2258 Practice for Sampling Yarn for TestingD2612 Test Method for Fiber Cohesion in Sliver and Top(Static Tests)D3333 Practice for Sampling Manuf
8、actured Staple Fibers,Sliver, or Tow for TestingD4849 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:cohesive force, fiber cohesion, roving, sliver, t
9、enacity, top.3.2 For all other terms are related to textiles, refer toTerminology D123.4. Summary of Test Method4.1 This test method provides an indication of the ability offibers to hold together by measuring the force required to slidefibers in a direction parallel to their length. Specific length
10、s ofroving, sliver, or top are drafted between two pairs of rollers,with each pair moving at a different peripheral speed. The draftforces are recorded. Test specimens are then weighed and thelinear density calculated. Drafting tenacity, calculated as thedraft resisting force per unit linear density
11、, is considered to bea measure of the dynamic fiber cohesion.5. Significance and Use5.1 This test method for the determination of cohesion insliver, roving, or top in dynamic tests may be used for theacceptance testing of commercial shipments but caution isadvised since information on between-labora
12、tory precision islacking. Comparative tests as directed in 5.1.1 may be advis-able.5.1.1 If there are differences or practical significance be-tween reported test results for two laboratories (or more),comparative test should be performed to determine if there is astatistical bias between them, usin
13、g competent statistical assis-tance. As a minimum, test samples that are as homogeneous aspossible, drawn from the material from which the disparate testresults were obtained, and randomly assigned in equal numbersto each laboratory for testing. The test results from the twolaboratories should be co
14、mpare using a statistical test forunpaired data, at a probability level chosen prior to the testingseries. If a 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.1This test method is under the jurisd
15、iction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved July 1, 2018. Published August 2018. Originallyapproved in 1982. Last previous edition approved in 2012 as D4120 07(2012).DOI: 10.1520/D4120-07R18.2For referenc
16、ed 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 Con
17、shohocken, PA 19428-2959. United StatesThis international standard was developed in accordance 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 O
18、rganization Technical Barriers to Trade (TBT) Committee.15.2 The cohesive forces overcome in continuous drafting ofslivers, rovings, or tops are affected by surface lubricants andsuch fiber properties as linear density, surface configuration,fiber length, fiber crimp, and fiber-frictional characteri
19、stics.5.2.1 The concept of drafting is one of the most importantprinciples in the production of yarn from fibrous raw stock.5.2.2 The values of force to maintain drafting determined bythis method are induced by mechanical means similar to thoseused in textile processing.5.2.3 The attenuation of text
20、ile fiber strands while in motionclosely approximates actual textile processing conditions, andthe relative values of force may be used to predict processingbehaviors.5.3 Fiber cohesion is affected by the alignment of fiber inthe textile strand and strand compaction in addition to thefactors listed
21、in 5.2.Although fibers are more nearly aligned indraw sliver than in card sliver, the draw sliver is more compact.Thus, for a given production run, the drafting forces are higherfor draw sliver than for card sliver.5.4 In addition to the aforementioned effects on draftingforces, the direction of spe
22、cimen movement through draftingrollers may give different drafting force. Fibers in slivers mayhave hooks of varying severity at one or both ends. Passagethrough drafting rollers results in higher drafting forces whenthe predominance of fiber hooks are oriented in the trailingmode of the strand.6. A
23、pparatus and Materials6.1 Cohesion Meter,3with rollers and controls for varyingdrafts and rates of drafting.6.2 Tensiometer,3with accessory equipment including mea-suring heads, integrator, (or computer or programmablecalculator), and recorder for sensing, accumulating, and re-cording drafting force
24、s.6.3 Calibration Mass, 1 kg, NBS Class T.6.4 Tachometer, capable of measuring roll surface speed towithin 0.1 m/min.6.5 Balance, with sufficient capacity and sensitivity toweigh specimens to within 0.1 % of specimen mass.7. Sampling7.1 Lot SamplingAs a lot sample for acceptance testing,take at rand
25、om 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 specification or
26、 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 unit to prov
27、ide a sampling planwith a meaningful producers risk, consumers risk, acceptable qualitylevel, and limiting quantity level.7.2 Laboratory Sample As a laboratory sample foracceptance testing, take at random from each shipping con-tainer in the lot sample the number of laboratory sampling unitsas direc
28、ted in an applicable material specification or otheragreement between purchaser and supplier such as an agree-ment to use Practice D3333 or Practice D2258. Preferably, thesame number of laboratory sampling units are taken from eachshipping container in the lot sample. If differing numbers oflaborato
29、ry 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 mlong.7.3 Test Specimens From each laboratory samplingunit, take one s
30、pecimen. If the standard deviation determinedfor the laboratory sample is more than a value agreed uponbetween the purchaser and supplier, continue testing onespecimen from each unit in the laboratory sample until thestandard deviation for all specimens tested is not more than theagreed to value or,
31、 by agreement, stop testing after a specifiednumber.8. Preparation and Calibration of Equipment8.1 Install the tensiometer measuring head in the cohesionmeter. Selection of the proper capacity head may be deter-mined by trial tests on the materials to be tested, or previousexperience with a given pr
32、oduct.8.2 Calibrate the apparatus as directed in the manufacturersinstructions.8.3 Verify the input and output speeds using a tachometer.8.4 Unless otherwise directed, set the draft ratio for 1.25, thematerial input speed to 5 m/min, the timer to give an input testlength of 10 m and the integration
33、period for 1 min.8.5 Set the gage spacing of the drafting rollers for 1.4 themean staple length of the fiber in the test specimen.8.5.1 Use the staple length determined using Test MethodD1440 or Test Method D1447 for cotton, or the staple lengthassigned by the fiber producer to manufactured fibers d
34、evel-oped for processing on the cotton system. For wool ormanufactured fibers with great variability in their lengthdistribution and developed for processing on a long staple fibersystem, use the fiber length which includes 95 % of the fibersin the specimen as determined from a fiber sorting, using
35、TestMethods D519 or D1575.9. Conditioning9.1 Precondition and condition the laboratory samples asdirected in Practice D1776.10. Procedure10.1 Test the adequately conditioned specimens in thestandard atmosphere for testing textiles that is 21 6 1C (70 62F) and 65 6 2 % relative humidity.3The sole sou
36、rce of supply of the apparatus known to the committee at this timeis Rothschild, Zurich, Switzerland, and it may be obtained from Lawson-HemphillSales, Inc., P.O. Drawer 6388, Spartanburg, SC 29304. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadqu
37、arters. Your comments will receive careful consideration at a meeting of theresponsible technical committee,1which you may attend.D4120 07 (2018)210.2 With instrument at slow speed (2 m/min), start test bypressing CONTINUOUS RUN button on the cohesion meterand threading the specimen strand through i
38、nput rollers, aroundmeasuring head guide roller and through output (delivery)rollers.10.3 Operate 10 to 15 s, or long enough for slack to beremoved from strand and tension to build up on measuringhead. Turn the tensiometer range selector switch to the positionwhich most nearly keeps the galvanometer
39、 needle at mid-scale.Change speed to 5 m/min, press timer to start the automatic 10m test length and immediately cut the specimen strand evenwith the front edge of the discharge chute.10.4 If an on-line computer or programmable calculator isused, run for 1 min taking a minimum of 50 readings, or,10.
40、4.1 If an integrator is used, press the SINGLE pushbutton and record the integrator value when the cohesion meterautomatically stops at the 10-m length.10.5 Cut the delivered specimen strand even with the frontedge of the discharge chute and weigh to the nearest 0.1 g.10.6 Continue as directed in 10
41、.2 10.5 until the necessarynumber of specimens have been tested.11. Calculation11.1 Calculate the dynamic cohesion as the cohesive tenac-ity of each specimen to the nearest 0.1 mgf/tex, using Eq 1.Cohesive tenacity, mgf/tex 5 F 3L/M (1)where:F = drafting force, gf,L = specimen length, m, andM = spec
42、imen mass, g.NOTE 3Drafting tenacity as micronewtons per tex (N/tex) is numeri-cally equal to drafting tenacity as mgf/tex times 9.81.11.2 Calculate the average drafting tenacity for each labo-ratory sample testing direction and for the lot sample to thenearest 0.1 mgf/tex.11.3 Calculate the standar
43、d deviation, the coefficient ofvariation, or both, for the laboratory sample and the lot sample,if requested.12. Report12.1 State that the specimens were tested as directed inASTM Test Method D4120. Describe the materials tested byfiber type, staple length, nominal linear density of the fibers inthe
44、 material (if known), crimp of the fibers (if known),processing step from which the material was obtained, andmethod of sampling used.12.2 Report the following information:12.2.1 The number of specimens tested in each laboratorysample testing direction,12.2.2 The average cohesive tenacity for each l
45、aboratorysample testing direction,12.2.3 The average cohesive tenacity for the lot sample, and12.2.4 The standard deviation, coefficient of variation, orboth, for each laboratory sample testing direction and the lotsample, if calculated.13. Precision and Bias13.1 PrecisionThe precision for measuring
46、 fiber cohesionin dynamic tests as drafting tenacity is being determined.13.2 BiasThe value for dynamic fiber cohesion as mea-sured by drafting tenacity can only be defined in terms ofspecific methods. Within this limitation, the procedure in thistest method for determining this property has no know
47、n bias.14. Keywords14.1 fiber cohesion; textile strandASTM International 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 r
48、ights, and the riskof infringement of such rights, are entirely their 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 f
49、or revision of this standard or for additional standardsand should 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 Standards, 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 multi
