1、Designation: D 4120 07Standard Test Method forFiber Cohesion in Roving, Sliver, and Top in Dynamic Tests1This standard is issued under the fixed designation D 4120; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 maintaindrafting in r
3、ovings, 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 D 2612.1.2 This standard
4、 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
5、Standards:2D 123 Terminology Relating to TextilesD 519 Test Method for Length of Fiber in Wool TopD 1440 Test Method for Length and Length Distribution ofCotton Fibers (Array Method)D 1447 Test Method for Length and Length Uniformity ofCotton Fibers by Fibrograph MeasurementD 1575 Test Method for Fi
6、ber Length of Wool in ScouredWool and in Card SliverD 1776 Practice for Conditioning and Testing TextilesD 2258 Practice for Sampling Yarn for TestingD 2612 Test Method for Fiber Cohesion in Sliver and Top(Static Tests)D 3333 Practice for Sampling Manufactured Staple Fibers,Sliver, or Tow for Testin
7、gD 4849 Terminology Relating to Yarns and Fibers3. Terminology3.1 For all terminology relating to D13.58, Yarns andFibers, refer to Terminology D 4849.3.1.1 The following terms are relevant to this standard:cohesive force, fiber cohesion, roving, sliver, tenacity, top.3.2 For all other terms are rel
8、ated to textiles, refer toTerminology D 123.4. 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 lengths ofroving, sliver, or top are drafted betw
9、een 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, is considered to bea measure of the dynam
10、ic 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-laboratory precision islacking. Comparative tests
11、 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, using competent statistical assis-tance. As a m
12、inimum, 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 two1This test method is under the jurisdiction of ASTM Committee D13 on
13、 Textilesand is the direct responsibility of Subcommittee D13.58 on Yarns and Fibers.Current edition approved Jan. 1, 2007. Published January 2007. Originallyapproved in 1982. Last previous edition approved in 2001 as D 4120 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or
14、contact 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 States.laboratories shoul
15、d be compare 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.5.2 The cohesive forces overco
16、me 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 characteristics.5.2.1 The concept of drafting is one of the most importantprinciples in the produ
17、ction 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 textile fiber strands while in motionclosely approximates actual textile processing conditi
18、ons, 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 in 5.2. Although fibers are more nearly aligned indraw sliver than in card sliver, the
19、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 specimen movement through draftingrollers may give different drafting force. Fibers in sl
20、ivers 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. Apparatus and Materials6.1 Cohesion Meter,3with rollers and controls for varyingdrafts
21、and rates of drafting.6.2 Tensiometer,3with accessory equipment includingmeasuring heads, integrator, (or computer or programmablecalculator), and recorder for sensing, accumulating, and re-cording drafting forces.6.3 Calibration Mass, 1 kg, NBS Class T.6.4 Tachometer, capable of measuring roll surf
22、ace 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 random the number of shipping containers directed inthe applicable material specification or
23、 other agreement be-tween the purchaser and supplier, such as an agreement to usePractice D 3333 or Practice D 2258. Consider shipping con-tainers to be the primary sampling units.NOTE 2An adequate specification or other agreement between thepurchaser or supplier requires taking into account the var
24、iability 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 risk, consumers risk, acceptable qualit
25、ylevel, and limiting quantity level.7.2 Laboratory SampleAs a laboratory sample for ac-ceptance testing, take at random from each shipping containerin the lot sample the number of laboratory sampling units asdirected in an applicable material specification or other agree-ment between purchaser and s
26、upplier such as an agreement touse Practice D 3333 or Practice D 2258. 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 shippingcontainers in the lot sample, determin
27、e 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 SpecimensFrom each laboratory sampling unit,take one specimen. If the standard deviation determined for thelaboratory sample is more than a
28、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 specified number.8. Preparation and Calibration of
29、 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 product.8.2 Calibrate the apparatus as directed in the manufacturersinstructions.8.3 Ve
30、rify 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 period for 1 min.8.5 Set the gage spacing of the drafting rollers for 1.43 themean st
31、aple length of the fiber in the test specimen.8.5.1 Use the staple length determined using Test MethodD 1440 or Test Method D 1447 for cotton, or the staple lengthassigned by the fiber producer to manufactured fibers devel-oped for processing on the cotton system. For wool ormanufactured fibers with
32、 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 TestMethods D 519 or D 1575.9. Conditioning9.1 Precondition and condition the labo
33、ratory samples asdirected in Practice D 1776.10. 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 source of supply of the apparatus known to the committee at this timeis Rothschild
34、, 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 InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theres
35、ponsible technical committee,1which you may attend.D412007210.2 With instrument at slow speed (2 m/min), start test bypressing CONTINUOUS RUN button on the cohesion meterand threading the specimen strand through input rollers, aroundmeasuring head guide roller and through output (delivery)rollers.10
36、.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 needle at mid-scale.Change speed to 5 m/min, press timer to start the automatic 10m te
37、st 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,10.4.1 If an integrator is used, press the SINGLE pushbutton and record the integrator val
38、ue 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 10.2-10.5 until the necessarynumber of specimens have been tested.11. Calculation11.1 Cal
39、culate 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 F3 L/M (1)where:F = drafting force, gf,L = specimen length, m, andM = specimen mass, g.NOTE 3Drafting tenacity as micronewtons per tex (N/tex) is numeri-cally eq
40、ual 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 standard deviation, the coefficient ofvariation, or both, for the laboratory sample and the lo
41、t sample,if requested.12. Report12.1 State that the specimens were tested as directed inASTM Test Method D 4120. Describe the materials tested byfiber type, staple length, nominal linear density of the fibers inthe material (if known), crimp of the fibers (if known),processing step from which the ma
42、terial 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 laboratorysample testing direction,12.2.3 The average cohesive tenacity for the lot sam
43、ple, 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 fiber cohesionin dynamic tests as drafting tenacity is being determined.13.2 BiasThe
44、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 known bias.14. Keywords14.1 fiber cohesion; textile strandASTM International takes no posi
45、tion 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 rights, and the riskof infringement of such rights, are entirely their own responsibili
46、ty.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 for revision of this standard or for additional standardsand should be addressed to AST
47、M 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
48、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 multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D4120073
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