1、Designation: D 2968 95 (Reapproved 2001)Standard Test Method forMed and Kemp Fibers in Wool and Other Animal Fibers byMicroprojection1This standard is issued under the fixed designation D 2968; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. 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 covers the determination by micro-projection of the percentage of medullated
3、fibers (med andkemp fibers) 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 establis
4、h appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 123 Terminology Relating to Textile Materials2D 2130 Test Method for Diameter of Wool and OtherAnimal Fibers by Microprojection23. Terminolog
5、y3.1 DefinitionsFor definitions of other textile terms usedin this test method, refer to Terminology D 123.3.2 Definitions of Terms Specific to This Standard:3.2.1 kemp fiber, na medullated animal fiber in which thediameter of the medulla is 60 %, or more, of the diameter of thefiber.3.2.2 med fiber
6、, na medullated animal fiber in which thediameter of the medulla is less than 60% of the diameter of thefiber.3.2.3 medulla, nin mammalian hair fibers, the more orless continuous cellular marrow inside the cortical layer inmost medium and coarse fibers.3.2.4 medullated fiber, nan animal fiber that i
7、n its originalstate includes a medulla.3.2.5 wool, nthe fibrous covering of the sheep, ovisspecies.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
8、 ofmed and kemp fibers are expressed as percentages of the totalnumber of fiber images examined.5. Significance and Use5.1 Test Method D 2968 for the determination of med andkemp fibers by microprojection may be used for the acceptancetesting of commercial shipments of wool and other animalfibers, b
9、ut 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 inrepo
10、rted test results when using Test Method D 2968 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 of
11、bias. 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 t
12、wolaboratories 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
13、 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
14、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
15、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 D 2130.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is th
16、e direct responsibility of Subcommittee D13.13 on Wool and Wool Felt.Current edition approved Sept. 10, 1995. Published December 1995. Originallypublished as D 2968 71 T. Last previous edition D 2968 89.2Annual Book of ASTM Standards, Vol 07.01.1Copyright ASTM, 100 Barr Harbor Drive, West Conshohock
17、en, PA 19428-2959, United States.7. Sampling7.1 Adequate sampling procedures for loose fibers (grease,pulled, and scoured), sliver, top, yarn, and fabric are describedin Test Method D 2130.8. Procedure8.1 Prepare the test specimens, calibrate the microprojector,condition the specimens, and prepare t
18、he slides by use of theheavy-duty cross-section device as directed in Test MethodD 2130. Have two operators independently prepare at least oneslide for each test specimen.8.2 Have each of the two operators make observations usingthe procedure specified in Test Method D 2130, except thatonly medullat
19、ed fibers need be measured. For such fibers,measure the diameter of both the medulla and the fiber,calculate their ratio, and classify the fiber as either med orkemp as defined in 3.2.1 and 3.2.2. For every fiber examined,record whether it is unmedullated, med, or kemp. See Fig. 1.8.3 Count and reco
20、rd the number of med and kemp fibersand the total number of animal fibers examined. Unlessotherwise directed in an applicable specification or by agree-ment, each operator should observe 500 fibers for a total of1000 fibers.9. Calculation9.1 Calculate, to the nearest 0.1 %, the med and kemp fibersco
21、ntent using (Eq 1) and (Eq 2):med fibers, % 5 100 m/n (1)kemp fibers, % 5 100 k/n (2)where:m = number of med fibers observed,k = number of kemp fibers observed, andn = total number of animal fibers observed.10. Report10.1 State that the specimens were tested as directed in TestMethod D 2968. Describ
22、e the material or product sampled andthe method used.10.2 Report the following information:10.2.1 The med fibers content,10.2.2 The kemp fibers content, and10.2.3 The total number of animal fibers observed.11. Precision and Bias11.1 Interlaboratory Test Data3An interlaboratory testwas conducted in 1
23、970 in which three randomly drawn samplesfrom one lot of mohair top were tested in each of fivelaboratories. Two operators in each laboratory each examined500 fibers per sample. The test results for med fibers and kempfibers were found to be free of bias due to sampling or testingerrors for nine of
24、the ten operators involved.11.1.1 Interlaboratory test data are on file only for mohairtop. These test results were found to be free of bias due tosampling and testing errors for nine out of ten operators. Sincesimilar data for med and kemp measured on other types ofanimal fibers or mohair samples r
25、emoved from forms otherthan top are not on file, no statements can be made concerningthe bias measurements made on such samples.11.1.2 Test results for med and kemp fibers are reported asa percent of the fibers examined. Such test results have abinomial distribution and for the small percentages of
26、interestwould require a transformation when analyzing the data. Forthis reason, the precision of test results is evaluated in terms ofthe count of med fibers observed and the count of kemp fibersobserved in the 1000 fibers examined for a single test result.Such counts have a Poisson distribution and
27、 may be compareddirectly without requiring a transformation.11.2 Critical DifferencesTwo counts of med fibers in testresults or two counts of kemp fibers in test results should be3Supporting data are available from ASTM Headquarters. Request RR:D13-1036.NOTE 1The contrast between the solid and the h
28、ollow portions of the medullated fibers is significantly reduced when the medulla becomes filled withmounting medium.FIG. 1 Types of Medulla in Wool and Mohair FibersD 29682considered significantly different at the 95 % probability levelif the smaller of the two counts is equal to or less than the v
29、aluelisted in Table 1.NOTE 1In comparing observed counts for test results from each oftwo different laboratories, test results from two operators within the samelaboratory, or other similar cases, Table 1 may be used, only if acomparison based on recent data obtained on specimens randomly drawnfrom
30、one sample of the material to be evaluated has verified the absenceof bias between the two specific laboratories or operators.11.3 Confidence LimitsSingle counts of med fibers orsingle counts of kemp fibers in a test result have the 95 %confidence limits listed in Table 2.11.4 BiasTest Method D 2968
31、 for testing the percentagesof med and kemp fibers in wool and other animal fibers has noknown bias and may be used as a referee method.12. Keywords12.1 animal fibers (except wool); microscopical examina-tion; woolThe American Society for Testing and Materials takes no position respecting the validi
32、ty of any patent rights asserted in connectionwith any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any suchpatent rights, and the risk of infringement of such rights, are entirely their own responsibility.This standard is subjec
33、t 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 ASTM Headquarters. Your comme
34、nts will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make yourviews known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted
35、 by ASTM, 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 above address or at610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or throug
36、h the ASTM website (www.astm.org).TABLE 1 Values of b for Critical Differences in Number of Medor Kemp Fiber Counts, a and b, for Two Test ResultsAr=a+bbr=a+bbr=a+bbr=a+bb1 0 26 7 51 18 76 282 0 27 7 52 18 77 293 0 28 8 53 18 78 294 0 29 8 54 19 79 305 0 30 9 55 19 80 306 0 31 9 56 20 81 317 0 32 9
37、57 20 82 318 0 33 10 58 21 83 329 1 34 10 59 21 84 3210 1 35 11 60 21 85 3211 1 36 11 61 22 86 3312 2 7 2622 73 381 3238 3414 2 9 2642 95 3 40136524 03516 3 4113662491357 4 2 46725 2 618 431 82 9339 4 56925 4 720 5 4515702695321 5 4615712696377 67227 7 823 6 481 32 9834 9 77428 925 7 50 17 75 28 100
38、 39AThe probability level for the critical difference is 95 %, for two-sided limits. If theobserved value of b 100, use the following:b 5 c 2 1 2 k=cwhere:b = calculated value of b, rounded to the nearest whole number,c = r/ 2, andk = 1.386 for the 95 % probability level.TABLE 2 95 % Confidence Limi
39、ts for Number of Counts per TestResultsAObservedCountLowerLimitUpperLimitObservedCountLowerLimitUpperLimit0 0.0 3.71 0.0 5.6 26 17.0 38.12 0.2 7.2 27 17.8 39.33 0.6 8.8 28 18.6 40.54 1.1 10.2 29 19.4 41.65 1.6 11.7 30 20.2 42.86 2.2 13.1 31 21.1 44.07 2.8 14.4 32 21.9 45.28 3.4 15.8 33 22.7 46.49 4.
40、1 17.1 34 23.5 47.510 4.8 18.4 35 24.4 48.711 5.5 19.7 36 25.2 49.812 6.2 21.0 37 26.0 51.013 6.9 22.2 38 26.9 52.214 7.6 23.5 39 27.7 53.315 8.4 24.7 40 28.6 54.516 9.1 26.0 41 29.4 55.617 9.9 27.2 42 30.3 56.818 10.7 28.4 43 31.1 57.919 11.4 29.6 44 32.0 59.120 12.2 30.8 45 32.8 60.221 13.0 32.1 4
41、6 33.7 61.422 13.8 33.3 47 34.5 62.523 14.6 34.5 48 35.4 63.624 15.4 35.7 49 36.2 64.825 16.2 36.9 50 37.1 65.9ALower confidence limit for counts = c 1-(19 c)t(19 c)1/23Upper confidence limit for counts = d 1-(19 d)+t (19 d)1/23where:c = observed number of counts,d = c+1,andt = value of Students t for infinite degrees of freedom, two-sided limits, andthe specified probability level (t = 1.960 at the 95 % probability level).D 29683
