1、Designation: D 1576 90 (Reapproved 2001)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 (e) 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 a
3、ll 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 1T
4、he 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 cover
5、ed 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 pr
6、actices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 123 Terminology Relating to Textiles2D 1060 Practice for Core Sampling of Raw Wool in Pack-ages for Determination of Percentage of Clean Wool FiberPresent2D 1776 Practice for C
7、onditioning Textiles for Testing2D 2258 Practice for Sampling Yarn for Testing2D 2462 Test Method for Moisture in Wool by Distillationwith Toluene2D 2495 Test Method for Moisture in Cotton by Oven-Drying2D 2525 Practice for Sampling Wool for Moisture2D 2654 Test Methods for Moisture in Textiles3D 33
8、33 Practice for Sampling Man-Made Staple Fibers,Sliver, or Tow for Testing43. 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
9、 and 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
10、may 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.5There may also be a slight additional loss in mass caused by theevaporation of volatile material other tha
11、n water, 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 an
12、d the 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 ma
13、ss of 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 10.3.1.5 oven-dried, adjthe condition of a material that hasbeen heated under prescribed conditions of temperature andhumidity
14、until there is no further significant change in its mass(see 3.1.2).3.1.5.1 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 mater
15、ial willonly be moisture-free when the air supplied to the drying ovenhas been previously desiccated.1This test method is under the jurisdiction of ASTM Committee D13 on Textiles,and is the direct responsibility of Subcommittee D13.13 on Wool and Wool Felt.Current edition approved Aug. 31, 1990. Pub
16、lished October 1990. Originallypublished as D 1576 58. Last previous edition D 1576 84.2Annual Book of ASTM Standards, Vol 07.01.3Discontinued; see 1997 Annual Book of ASTM Standards, Vol 07.01.4Annual Book of ASTM Standards, Vol 07.02.5Toner, R. K., Bowen, C. F., and Whitwell, J. C., “Equilibrium M
17、oistureRelations for Textile Fibers,” Textile Research Journal, Vol 17, January 1947, pp. 7to 18.1Copyright ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.3.1.6 pulled wool, nwool taken from the pelt of a slaugh-tered sheep and which has not been commercially scoured.(s
18、yn. 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 defined in the Wool ProductsLabeling Act as amended in 1980, “the resulting fiber whenwool has been woven or felted into a wool product which
19、,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 reprocessed wool has beenspun, woven, knitted, or felted into a wool product which, afterhaving been used in any way by the ultimate consumer,sub
20、sequently 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“reused 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 Dis
21、cussionAlthough 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 ProductsLabeling Act, “the terms 8virgin or 8new as descriptive of awool product, or any fiber or part thereof, shall not be usedwhen the product or pa
22、rt so described is not composed whollyof new or virgin fiber which has never been reclaimed from anyspun, woven, knitted, felted, braided, bonded, or otherwisemanufactured or used product”.3.1.11 wool, nthe fibrous covering of the sheep, Ovisspecies.3.1.11.1 DiscussionFor the purposes of this method
23、, 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 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, or
24、hair 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 been reclaimed from anywoven or felted wool product”.3.1.13 For the definition of other textile terms used in thismethod, refer to Terminology
25、 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 loss in mass is considered moisture andreported as either moisture content or moisture regain. Direc-tions are given for the adjustment of th
26、e 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 the mois-ture in wool by distillation with toluene is the preferred methodfor testing wool for moisture for the acceptance testing ofcommerc
27、ial 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 instead.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 whe
28、n using Test Method D 1576 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, t
29、he 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
30、 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 the light ofthe kn
31、own 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, or any other purpose forwhich a high degree of reproducibility is not necessary (seeSection 13).6. Apparatus6.1 Oven, ventilated and thermo
32、statically 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 Containers, of perforated metal if weighing isto be performed in the drying enclosure; or containers that canbe hermetically sealed (such
33、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 sealed. Masonjars have been found to be satisfactory where the sample sizeis not too great. For larger samples, bags of various plasticmaterial
34、s 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 example).6.4 Balance, having a capacity adequate for weighing speci-mens and containers, and a sensitivity of 0.005 g.7. Sampling7.1 Lot SampleA
35、s a lot sample for acceptance testing,take at random the number of shipping containers directed inapplicable material specification or other agreement betweenthe purchaser and the supplier, such as an agreement to usePractice D 2525 for bales of fiber and containers of top orsliver or to use Practic
36、e D 2258 for beams or cases of yarn.Consider shipping containers to be the primary sampling unit.NOTE 2An adequate specification or other agreement between thepurchaser and supplier requires taking into account the variability betweenshipping containers, between laboratory sampling units within a sh
37、ippingcontainer, and test specimens within a laboratory sampling unit to producea sample plan with a meaningful producers risk, consumers risk,acceptable quality level, and limiting quality level.7.2 Use extreme care to prevent gain or loss of moistureduring the sampling operation and the transfer o
38、f material toD 15762the sampling container. Weigh each portion of the sample andits container immediately after sampling. Subtract the taremass of the 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
39、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, 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
40、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 laboratory samples to specimens.NOTE 3Condition the laboratory samples as directed in Section 9before preparing the specimens from them.8. Number of
41、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 laboratory sampling unit will be no morethan 0.5 percentage points above or below the true average forthe laboratory sampling unit. Determine the numbe
42、r 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 records in the userslaboratory as directed in the test method, calculate the requirednumber of specimens per laboratory sampling unit using Eq 1:n 5 ts/
43、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 indi-vidual observations on similar materials in the userslaboratory under conditions of single operator preci-sion,t = the value of Students t for t
44、wo-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 variation.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
45、 fixed number of six specimens per labora-tory sampling unit. This number of specimens per laboratorysampling unit is calculated using s = 0.60 percentage pointswhich is a somewhat larger value of s than is usually found inpractice. When a reliable estimate of s for the users laboratorybecomes avail
46、able, Eq 1 will usually require fewer than sixspecimens per laboratory sampling unit.9. Conditioning9.1 Condition the lot sample (or laboratory sample(s) byexposure to moving air in the laboratory atmosphere in whichthe testing is to be done, until equilibrium for testing isachieved.NOTE 4Preconditi
47、oning and conditioning as directed in PracticeD 1776 is acceptable but not necessary, since the object of the condition-ing for the purpose of this test is merely to stabilize the sample, that is, tobring all parts of the sample to moisture equilibrium with the prevailingatmosphere in order that cha
48、nges 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 record 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 ob
49、served 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 in excess of 0.10 % of theaverage as determined by three successive weighings using theprocedure in either 10.1.1 or 10.1.2 to obtain the oven-dry mass
