1、Designation: D1448 11Standard Test Method forMicronaire Reading of Cotton Fibers1This standard is issued under the fixed designation D1448; 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 pare
2、ntheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the determination of themicronaire reading o
3、f loose cotton fibers by measuring theresistance of a specific mass (plug) of cotton fibers to air flowunder prescribed conditions.NOTE 1For other methods for determining the fineness of fibers basedon the air-flow principle, refer to Test Method D1449, Test Method forSpecific Area and Immaturity Ra
4、tio of Cotton Fibers (ArealometerMethod),2and to Test Method D1282, Test Method for Resistance to AirFlow as an Indication of Average Fiber Diameter of Wool Top, CardSliver, and Scoured Wool.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
5、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 TextilesD1282 Test Method for Resistance to Airflow
6、as an Indica-tion of Average Fiber Diameter of Wool Top, Card Sliver,and Scoured WoolD1441 Practice for Sampling Cotton Fibers for TestingD1449 Discontinued 1978; Method of Test for SpecificArea and Immaturity Ratio of Cotton Fibers (ArealometerMethod)3D1776 Practice for Conditioning and Testing Tex
7、tilesD5867 Test Methods for Measurement of Physical Proper-ties of Cotton Fibers by High Volume InstrumentsD7139 Terminology for Cotton Fibers3. Terminology3.1 For all terminology related to D13.11, refer to Termi-nology D7139.3.1.1 The following terms are relevant to this standard:calibration cotto
8、n standards, fineness, micronaire reading.3.2 For all other terminology related to textiles, refer toTerminology D123.4. Summary of Test Method4.1 The resistance a specific mass (plug) of cotton fibersoffers to the flow of air is measured as an approximateindication of the fineness of fiber. A prede
9、termined mass ofloose cotton fibers is placed in the specimen holder andcompressed to a fixed volume. The resistance to air flow ismeasured and expressed as a micronaire reading.5. Significance and Use5.1 This test method is considered satisfactory for accep-tance testing when the levels of the labo
10、ratories are controlledby the use of the same reference standard cotton samplesbecause the current estimates of between-laboratory precisionare acceptable under these conditions. If there are differencesof practical significance between reported test results for twolaboratories (or more), comparativ
11、e tests should be performedto determine if there is a statistical bias between them, usingcompetent statistical assistance. As a minimum, ensure the testsamples to be used are as homogeneous as possible, are drawnfrom the material from which the disparate test results wereobtained, and are randomly
12、assigned in equal numbers to eachlaboratory for testing. The test from the two laboratories shouldbe compared using a statistical test for unpaired data, at aprobability level chosen prior to the testing series. If a bias isfound, either its cause must be found and corrected, or futuretest results f
13、or that material must be adjusted in considerationof the known bias.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.11 on Cotton Fibers.Current edition approved Jan. 1, 2011. Published January 2011. Originallyapproved
14、in 1954 to replace portions of D414. Last previous edition approved in2005 as D144805. DOI: 10.1520/D1448-11.2For 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 sta
15、ndards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 The micronaire reading of cotton fiber
16、s is a function ofboth fineness and maturity and is related to mill processingperformance and to the quality of the end products. Factorscorrelated with micronaire reading include cleaning efficiency,neppiness, and the strength and uniformity of the yarn.NOTE 2A modification of this test method is u
17、sed in commercialtrading to select bales which will conform to contract guarantees forspecified micronaire readings (refer to D5867). For this purpose, it is usualpractice to test only one specimen per sample.6. Apparatus and Materials6.1 Air-Flow Instrument, calibrated in micronaire readingsor yiel
18、ding numerical readings from which micronaire readingscan be computed.4NOTE 3Instruments available to measure resistance to air flow usecompressed air or vacuum and are constructed to measure air flow underconstant pressure drop across the plug, to measure pressure drop when aconstant flow of air is
19、 maintained, or to indicate resistance to air flow fromboth a balanced and unbalanced wheatstone bridge.6.2 Micronaire Scale, appropriate for instrument.NOTE 4The air instrument scale is calibrated for a specific airregulator and tube. The model number on the scale should corrrespond tothe model num
20、ber of the instrument. If a regulator or tube is replaced, andthe same scale is to be used, the new parts must be of the same make andmodel as those originally furnished with the instrument (1).56.3 Balance, having a capacity suitable for mass of thespecimen to be used and a sensitivity of at least
21、0.2 % of themass.6.4 Air Supply, to furnish the required pressure or vacuum tooperate the instrument in accordance with the manufacturersinstructions.6.5 International Calibration Cotton Standards, with as-signed micronaire readings.7. Sampling and Selection of Specimens7.1 Take the test specimen by
22、 random sampling from thelaboratory sample prepared as directed in Practice D1441.NOTE 5In commercial testing consider the classers sample thatrepresents both sides of the bale as the laboratory sample. Take portionsfor each specimen from the end of the classers sample, to be represen-tative of all
23、layers, or take two test specimens, one from each side of thebale.8. Conditioning8.1 Bring the laboratory sample from the prevailing atmo-sphere to moisture equilibrium in the standard atmosphere fortextile testing as directed in Practice D1776. Preconditioning isnot necessary.NOTE 6The effect of co
24、nditioning is small for cottons having micron-aire readings below 3.5 but is appreciable for readings of 5.0 and above (2,3).9. Procedure9.1 Set up and verify the instrument as directed in themanufacturers instructions. Adjust the instrument if necessaryto secure values assigned to the International
25、 CalibrationCotton Standards at the beginning of each testing period.Perform test on two specimens from each of the standardcottons. If the average of the two results is not within 60.1 unitof the established micronaire reading, recheck the instrumentand the technique used by the operator. Check the
26、 instrumentagainst the standards again at the end of each testing period. Ifincorrect readings on the standards are obtained at the end of atesting period, discard the test results, recheck the instrument,and repeat the tests.NOTE 7Built-in calibration devices and calibration plugs alone giveonly ap
27、proximate results.9.2 Test the conditioned specimens in the atmosphere fortesting textiles.9.3 Remove obvious, large pieces of nonfibrous materials.Weigh out a test specimen having the mass specified for theinstrument. Place the weighed specimen in the fiber compres-sion cylinder, fluffing it with t
28、he fingers as it is packed into thecylinder to eliminate knotty balls, and being careful to place allthe fibers inside the cylinder. Insert or activate the fibercompression plunger. Turn on or activate the air flow, and readthe value to the nearest 0.1 unit reading.9.4 Test two specimens.10. Calcula
29、tion10.1 If the instrument readings are not in micronaire read-ings, compute micronaire readings from instrument readings inaccordance with manufacturers instructions.10.2 Calculate the average for the two specimens tested tothe nearest 0.1 micronaire reading.11. Report11.1 State that the test was c
30、arried out as directed in ASTMTest Method D1448.11.2 Report the following information:11.2.1 Type of material used and identification of thesamples by shipment, mark, lot numbers or bale numbers,whichever is applicable.11.2.2 Average readings to the nearest 0.1 micronaire read-ing.11.2.3 Make, type,
31、 and model of the instrument used.12. Precision and Bias12.1 Interlaboratory Test Data6An interlaboratory test iscarried out semi-annually in connection with the InternationalCalibration Cotton Standards Program (4). The data obtainedby the five laboratories designated to establish standard valuesfo
32、r check test numbers 29, 30, and 31 in 1971 and 1972 wereused as the basis for the precision and accuracy statements.One operator at each of the five laboratories tested threespecimens from each of six subsamples representing sixdifferent cottons. The subsamples for these tests were extractedfrom co
33、tton which had been hand blended and processed intopicker laps to obtain uniform material. The components of4Instruments commercially available.5The boldface numbers in parentheses refer to the list of references appended tothis test method.6Supporting data have been filed at ASTM International Head
34、quarters and maybe obtained by requesting Research Report No. RR:D13-1029.D1448 112variance calculated from the results of these tests and ex-pressed as standard deviations of micronaire reading are0.0628 for the single-operator component and 0.0230 for thebetween-laboratory component.12.2 Precision
35、For the components of variance in 12.1, theaverages of observed values should be considered significantlydifferent at the 95 % probability level if the differences exceedthe critical differences listed below for various number ofspecimens in the test:Critical Differences, MicronaireReadings, for the
36、 Conditions NotedANumber of Specimensin Each AverageSingle-OperatorPrecisionBetween-LaboratoryPrecision1 0.17 0.192 0.12 0.143 0.10 0.124 0.09 0.115 0.08 0.1010 0.05 0.08AThe critical differences were calculated using t = 1.960 which is based oninfinite degrees of freedom.NOTE 8The tabulated values
37、of the critical differences should beconsidered to be a general statement particularly with respect to between-laboratory precision. Before a meaningful statement can be made abouttwo specific laboratories, the amount of statistical bias, if any, betweenthem must be established with each comparison
38、being based on recent dataobtained on randomized specimens from one sample of the material beingtested.12.3 BiasThis method for the testing of the fiber finenessof cotton is accepted internationally for commercial tradingand has no known bias when the results are controlled at thestandard level by t
39、he use of International Calibration CottonStandards.13. Keywords13.1 cotton; fineness; micronaire readingREFERENCES(1) “Revised Micronaire Fiber-Fineness Scale for Use in Testing Ameri-can Upland Cottons,” Cotton Branch, PMA, U.S. Dept. of Agriculture,Washington, D. C., October, 1950.(2) Gates, F. R
40、., and Jennings, E. J., “The Effect of Relative Humidity onMicronaire Readings,” Texas Research Journal, TRJOA, Vol 23,1953, pp. 942944.(3) “Effect of Atmospheric Conditions on Testing Certain Cotton FiberProperties,” Cotton Branch, PMA, U. S. Dept. of Agriculture, Wash-ington, D.C., October, 1953.(
41、4) International Calibration Cotton Standards, United States Depart-ment of Agriculture, Washington, D.C., Revised January 1966.ASTM 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
42、 expressly advised that determination of the validity of any such patent rights, 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 r
43、evised, either reapproved or withdrawn. Your comments are invited either for 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
44、 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
45、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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D1448 113
