ASTM_D_2968_-_13.pdf

Designation:D296813Standard Test Method forMed and Kemp Fibers in Wool and Other Animal Fibers byMicroprojection1This standard is issued under the fixed designation D2968;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 covers the determination by micropro-jection of the percentage of medullated fibers(med and kempfibers)in wool or other animal fibers such as mohair,cashmere,alpaca,or camels hair in their various forms.1.2 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:2D123 Terminology Relating to TextilesD2130 Test Method for Diameter of Wool and OtherAnimalFibers by MicroprojectionD4845 Terminology Relating to Wool3.Terminology3.1 For all terminology related to D13.13,Wool and Felt,see Terminology D4845.3.1.1 The following terms are relevant to this standard:kemp fiber,med fiber,medulla,in mammalian hair fibers,medullated fiber,wool.3.2 For definitions of all other textile terms see TerminologyD123.4.Summary of Test Method4.1 The magnified images of a specimen of the animal fibersare examined.All medullated fibers are measured and classedas either med fibers or kemp fibers.The observed numbers ofmed and kemp fibers are expressed as percentages of the totalnumber of fiber images examined.5.Significance and Use5.1 Test Method D2968 for the determination of med andkemp fibers by microprojection may be used for the acceptancetesting of commercial shipments of wool and other animalfibers,but caution is advised since only a few types of animalfibers have been subjected to interlaboratory tests to ascertainthe precision of tests for med and kemp fibers by this testmethod.Comparative tests as directed in 5.1.1 may be advis-able.5.1.1 In case of a dispute arising from differences inreported test results when using Test Method D2968 foracceptance testing of commercial shipments,the purchaser andthe supplier should conduct comparative tests to determine ifthere is 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 whichare from a lot of material of the type in question.The testspecimens should then be randomly assigned in equal numbersto each laboratory for testing.The average results from the twolaboratories should be compared using Students t-test forunpaired data and an acceptable probability level chosen by thetwo parties before testing is begun.If a bias is found,either itscause must be found and corrected,or the purchaser and thesupplier must agree to interpret future test results in view of theknown bias.5.2 Knowledge of the incidence of med fibers and kempfibers in wool and other animal fibers is of importance tomanufacturers of woven or knitted fabrics because of theapparent dye resistance and light reflectance qualities of thesefibers.This is not to imply that all kemp fibers will resist dyeand all med fibers will accept dye normally.In practice,aproportion of kemp fibers will appear normal after dyeing anda proportion of med fibers will appear chalky white afterdyeing.From the perspective of visual and aesthetic problems,medullated fibers having an abnormally large diameter and ahigh degree of medullation are probably the worst kind.6.Apparatus and Material6.1 The apparatus and material required in this test methodare identical to those specified in Test Method D2130.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.13 on Wool and Felt.Current edition approved July 1,2013.Published August 2013.Originallyapproved in 1971.Last previous edition approved in 2008 as D2968 95(2008).DOI:10.1520/D2968-13.2For 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 7.Sampling7.1 Adequate sampling procedures for loose fibers(grease,pulled,and scoured),sliver,top,yarn,and fabric are describedin Test Method D2130.8.Procedure8.1 Prepare the test specimens,calibrate the microprojector,condition the specimens,and prepare the slides by use of theheavy-duty cross-section device as directed in Test MethodD2130.Have two operators independently prepare at least