1、Designation: D 1576 90 (Reapproved 2008)Standard Test Method forMoisture in Wool by Oven-Drying1This standard is issued under the fixed designation D 1576; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、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 of the amountof moisture present in ordinary commercial and industrialsamples of wool in al
3、l forms except grease wool, using theoven-drying technique.1.2 Formulas for calculating the moisture content (as-received basis) and moisture regain (oven-dried basis) aregiven. It is always important to use the correct term whichcorresponds to the basis used in the calculation (see 12.2.1).NOTE 1Th
4、e determination of moisture content for textile materials ingeneral is covered in Test Methods D 2654, and an optimal method fordetermining the moisture in wool by distillation with toluene is covered inTest Method D 2462. A method for sampling wool for the determinationof moisture in wool is covere
5、d in Practice D 2525. The oven-dryingmethod has been adapted for cotton in Test Method D 2495.1.3 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 pra
6、ctices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1060 Practice for Core Sampling of Raw Wool in Pack-ages for Determination of Percentage of Clean Wool FiberPresentD 1776 Practice for Con
7、ditioning and Testing TextilesD 2258 Practice for Sampling Yarn for TestingD 2462 Test Method for Moisture in Wool by DistillationWith TolueneD 2495 Test Method for Moisture in Cotton by Oven-DryingD 2525 Practice for Sampling Wool for MoistureD 2654 Test Methods for Moisture in Textiles3D 3333 Prac
8、tice for Sampling Manufactured Staple Fibers,Sliver, or Tow for Testing3. Terminology3.1 Definitions:3.1.1 grease wool, nwool taken from the living sheep andwhich has not been commercially scoured.3.1.2 moisture content, nthe amount of moisture in amaterial determined under prescribed conditions and
9、 expressedas a percentage of the mass of the moist material, that is, theoriginal mass comprising the oven-dried substance plus anymoisture present.3.1.2.1 DiscussionThe term “mass” is the correct desig-nation for the property commonly designated as “weight.”A slight amount of residual moisture may
10、not be removed from aspecimen subjected to oven drying because of the relative humidity ofthe ambient air. The amount of moisture retained by a specimen may beestimated from published data.4There may also be a slight additional loss in mass caused by theevaporation of volatile material other than wa
11、ter, the amount dependingon the characteristics of any added oils or emulsions.3.1.3 moisture-free, adjthe condition of a material thathas been exposed in an atmosphere of desiccated air until thereis no further significant change in its mass (see 3.1.2).3.1.3.1 DiscussionHeating the material and th
12、e desiccatedair to temperatures as high as 110C increases the rate ofmoisture loss but does not change the final equilibrium mass ofthe moisture-free material.3.1.4 moisture regain, nthe amount of moisture in amaterial determined under prescribed conditions and expressedas a percentage of the mass o
13、f the moisture-free material (seemoisture content).3.1.4.1 DiscussionIn this test method, the material isconsidered to be oven-dried after drying as described inSection 10.1This test method is under the jurisdiction of ASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D1
14、3.13 on Wool and Felt.Current edition approved Aug. 1, 2008. Published September 2008. Originallyapproved in 1958. Last previous edition approved in 2001 as D 1576 90 (2001).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For
15、Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Toner, R. K., Bowen, C. F., and Whitwell, J. C., “Equilibrium MoistureRelations for Textile Fibers,” Textile Research Journal, Vol 17, January 1947, pp. 7to 18.1Copyright ASTM
16、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.5 oven-dried, adjthe condition of a material that hasbeen heated under prescribed conditions of temperature andhumidity until there is no further significant change in its mass(see 3.1.2).3.1.5.1
17、DiscussionAn oven-dried material will retain asmall amount of moisture which is dependent on the tempera-ture and relative humidity of the atmosphere in contact with thematerial during the drying process.An oven-dried material willonly be moisture-free when the air supplied to the drying ovenhas bee
18、n previously desiccated.3.1.6 pulled wool, nwool taken from the pelt of a slaugh-tered sheep and which has not been commercially scoured.(syn. slipe wool, skin wool).3.1.7 raw wool, nwool or hair of the sheep in the grease,pulled, or scoured state. (See also scoured wool.)3.1.8 recycled wool, nas de
19、fined in the Wool ProductsLabeling Act as amended in 1980, “the resulting fiber whenwool has been woven or felted into a wool product which,without ever having been utilized in any way by the ultimateconsumer, subsequently has been made into a fibrous state, orthe resulting fiber when wool or reproc
20、essed wool has beenspun, woven, knitted, or felted into a wool product which, afterhaving been used in any way by the ultimate consumer,subsequently has been made into a fibrous state.”3.1.8.1 DiscussionIn the amended Act of 1980, the term“recycled wool” replaced the terms “reprocessed wool” and“reu
21、sed wool.”3.1.9 scoured wool, nwool from which the bulk of impu-rities has been removed by an aqueous or solvent washingprocess.3.1.9.1 DiscussionAlthough it is no longer in its originalraw state, scoured wool is generally accepted as raw wool.3.1.10 virgin wool, nas defined in the Wool ProductsLabe
22、ling Act, “the terms 8virgin or 8new as descriptive of awool product, or any fiber or part thereof, shall not be usedwhen the product or part so described is not composed whollyof new or virgin fiber which has never been reclaimed from anyspun, woven, knitted, felted, braided, bonded, or otherwisema
23、nufactured or used product”.3.1.11 wool, nthe fibrous covering of the sheep, Ovisspecies.3.1.11.1 DiscussionFor the purposes of this method, theword wool is used in the generic sense, and includes both woolas defined in the Wool Products Labeling Act of 1939 as wellas recycled wool as defined in the
24、 amended Act of 1980.3.1.12 wool, nas defined in the Wool Products LabelingAct of 1939, “the fiber from the fleece of the sheep or lamb, orhair of the Angora goat or Cashmere goat (and may include theso called specialty fibers from the hair of the camel, alpaca,llama, and vicuna) which has never bee
25、n reclaimed from anywoven or felted wool product”.3.1.13 For the definition of other textile terms used in thismethod, refer to Terminology D 123.4. Summary of Test Method4.1 A specimen of wool material is weighed and then driedto constant mass at 105 6 2C in an oven supplied withambient air. The lo
26、ss in mass is considered moisture andreported as either moisture content or moisture regain. Direc-tions are given for the adjustment of the observed results forany change in the moisture content after sampling and beforedrying.5. Significance and Use5.1 Test Method D 2462 for the determination of t
27、he mois-ture in wool by distillation with toluene is the preferred methodfor testing wool for moisture for the acceptance testing ofcommercial shipments. If, however, the purchaser and thesupplier agree, Test Method D 1576 for the determination ofthe moisture in wool by oven drying may be used inste
28、ad.Comparative tests as directed in 5.1.1, may be advisable.5.1.1 In case of a dispute arising from differences inreported test results when using Test Method D 1576 foracceptance testing of commercial shipments, the purchaser andthe supplier should conduct comparative tests to determine ifthere is
29、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 testspe
30、cimens 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, eit
31、her itscause must be found and corrected or the purchaser and thesupplier must agree to interpret future test results in the light ofthe known bias.5.2 This test method is a simple and convenient method forroutine process control, in-plant evaluation, estimation ofmoisture content of a lot of wool,
32、or any other purpose forwhich a high degree of reproducibility is not necessary (seeSection 13).6. Apparatus6.1 Oven, ventilated and thermostatically controlled in thetemperature range of 105 6 2C throughout the enclosure. Theoven may be of either the forced draft or the convection type.6.2 Weighing
33、 Containers, of perforated metal if weighing isto be performed in the drying enclosure; or containers that canbe hermetically sealed (such as glass weighing bottles) if thespecimen is to be cooled in a desiccator before weighing in theambient atmosphere.6.3 Sampling Containers, capable of being seal
34、ed. Masonjars have been found to be satisfactory where the sample sizeis not too great. For larger samples, bags of various plasticmaterials may be suitable if the wall thickness is sufficient toprovide a good moisture vapor barrier (at least 4 mil (approxi-mately 0.1 mm) for polyethylene, for examp
35、le).6.4 Balance, having a capacity adequate for weighing speci-mens and containers, and a sensitivity of 0.005 g.7. Sampling7.1 Lot SampleAs a lot sample for acceptance testing,take at random the number of shipping containers directed inapplicable material specification or other agreement betweenthe
36、 purchaser and the supplier, such as an agreement to useD 1576 90 (2008)2Practice D 2525 for bales of fiber and containers of top orsliver or to use Practice D 2258 for beams or cases of yarn.Consider shipping containers to be the primary sampling unit.NOTE 2An adequate specification or other agreem
37、ent between thepurchaser and supplier requires taking into account the variability betweenshipping containers, between laboratory sampling units within a shippingcontainer, and test specimens within a laboratory sampling unit to producea sample plan with a meaningful producers risk, consumers risk,a
38、cceptable quality level, and limiting quality level.7.2 Use extreme care to prevent gain or loss of moistureduring the sampling operation and the transfer of material tothe sampling container. Weigh each portion of the sample andits container immediately after sampling. Subtract the taremass of the
39、container to obtain the net mass at time ofsampling, M.7.3 Laboratory SampleAs a laboratory sample for ac-ceptance testing, proceed as follows:7.3.1 For wool fiber, take laboratory samples as directed inPractice D 1060 for cored samples or Practice D 3333 for handsamples.7.3.2 For wool sliver or top
40、, from each shipping container inthe lot sample, take one ball of top. From this ball of top, takeapproximately 2 m from the inside and 4 m from the outside ofthe ball.7.3.3 Take laboratory sampling units which weigh a mini-mum of 50 g. Follow the instructions in Practice D 2525 forreduction of the
41、laboratory samples to specimens.NOTE 3Condition the laboratory samples as directed in Section 9before preparing the specimens from them.8. Number of Specimens8.1 Take a number of specimens per laboratory samplingunit that the user can expect at the 95 % probability level thatthe test result for a la
42、boratory sampling unit will be no morethan 0.5 percentage points above or below the true average forthe laboratory sampling unit. Determine the number of speci-mens per laboratory sampling unit as follows:8.1.1 Reliable estimate of swhen there is a reliableestimate of s based upon extensive past rec
43、ords in the userslaboratory as directed in the test method, calculate the requirednumber of specimens per laboratory sampling unit using Eq 1:n 5 ts/E!2 (1)where:n = number of specimens per laboratory sampling unit(rounded upward to a whole number),s = reliable estimate of the standard deviation of
44、indi-vidual observations on similar materials in the userslaboratory under conditions of single operator preci-sion,t = the value of Students t for two-sided limits, a 95 %probability level, and the degrees of freedom associ-ated with the estimate of v, andE = 0.5 percentage points, the allowable va
45、riation.8.1.2 No Reliable Estimate of sWhen there is no reliableestimate of s for the users laboratory, do not use Eq 1 directly.Instead, specify the fixed number of six specimens per labora-tory sampling unit. This number of specimens per laboratorysampling unit is calculated using s = 0.60 percent
46、age pointswhich is a somewhat larger value of s than is usually found inpractice. When a reliable estimate of s for the users laboratorybecomes available, Eq 1 will usually require fewer than sixspecimens per laboratory sampling unit.9. Conditioning9.1 Condition the lot sample (or laboratory sample(
47、s) byexposure to moving air in the laboratory atmosphere in whichthe testing is to be done, until equilibrium for testing isachieved.NOTE 4Preconditioning and conditioning as directed in PracticeD 1776 is acceptable but not necessary, since the object of the condition-ing for the purpose of this tes
48、t is merely to stabilize the sample, that is, tobring all parts of the sample to moisture equilibrium with the prevailingatmosphere in order that changes in moisture level will not occur while thespecimens are being prepared and weighed.9.2 Weigh the conditioned sample(s) to the nearest 0.005 gand r
49、ecord the net mass(es), W.NOTE 5The net mass of the conditioned sample, W, and the net massat the time of sampling, M, will be used to convert the observed moisturecontent of the conditioned specimen to the moisture content at time ofsampling.9.3 From the weighed conditioned sample(s), take theappropriate size specimen(s) and weigh to the nearest 0.005 gto obtain the specimen mass B.10. Procedure10.1 Place the specimen(s) in the oven in a suitable con-tainer and dry to constant mass, defined as the absence of anyprogressive decrease in mass
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