1、Designation: D3790 79 (Reapproved 2006)1Standard Test Method forVolatile Matter (Moisture) of Leather by Oven Drying1This standard is issued under the fixed designation D3790; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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.This standard has been approved for use by agencies of the Department of Defense.1NOTEAdded research report information to Se
3、ction 10 editorially in September 2010.1. Scope1.1 This test method covers the determination of volatilematter (moisture) in all types of leather.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 stan
4、dard 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:2D2813 Practice for Sampling Leather for Physical andChemical TestsE180 Practice for Determining the Precision of ASTMMethods f
5、or Analysis and Testing of Industrial and Spe-cialty Chemicals33. Summary of Test Method3.1 The ground leather specimen is heated in a mechanical-convection oven for 16 h at 100C, placed in a desiccator,cooled, and reweighed. The loss in weight represents thevolatile matter.4. Significance and Use4.
6、1 The result obtained by this test is normally considered tobe the moisture content of the leather sample. This result isused to correct all other chemical tests to a moisture-free basis.4.2 Materials that are volatile under these conditions, otherthan water, may be present in the leather, although
7、their amountin any normal leather would be expected to be a very smallpercentage of the total volatile matter.4.3 Under the conditions of this test, certain materials inleather, such as protein fiber and chromium tanning salts, mayretain moisture. Other materials, such as tannins and oils, maybe oxi
8、dized. Both of these effects produce negative errors inthe moisture determination.4.4 The amount of volatile matter (moisture) released by agiven leather varies with (a) degree of grinding of the sample,(b) weight of sample taken, (c) temperature and time of theoven drying, (d) shape of the weighing
9、 container, and (e) typeof oven (gravity versus mechanical convection) used.4.5 Because of the above unknown errors, the result of thistest is a purely arbitrary value for the moisture content of thesample. It is, therefore, essential that the method be followedexactly in order to obtain reproducibl
10、e results among labora-tories. This is particularly true if other chemical analytical testsbeing performed on the same sample are reported on themoisture-free basis.5. Apparatus5.1 Weighing Bottle4, glass, low-form, cylindrical with aground-glass stopper of standard taper. The bottle shall have 706
11、5 mm inside diameter, and 33 6 3 mm overall height.5.2 Oven, mechanical-convection draft capable of setting at100C, with a thermoregulator system capable of holding oventemperature within 6 2C of set point.Athermometer accurateto 60.2C should be used to check and monitor the oven setpoint.5.3 Balanc
12、e, capable of weighing up to 100 g with anaccuracy of 60.001 g.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.06 on Chemical Analysis.Current edition approved Oct. 1, 2006. Published November 2006. Originallyapproved i
13、n 1979. Last previous edition approved in 2001 as D3790 - 79(2001)DOI: 10.1520/D3790-79R06E01.2For 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
14、 Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.4Weighing bottles that have been found to be satisfactory are the Kimble GlassCo. No. 15166 and 15165 with 71/15 standard-taper caps and are available frommost laboratory s
15、upply houses.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Desiccator, any convenient form or size, using anynormal desiccating agent such as calcium sulfate, calciumchloride, or silica gel.6. Sampling6.1 The leather shall be s
16、ampled in accordance with PracticeD2813.7. Procedure7.1 Insert the empty weighing bottle inside the invertedstoppered cap and place on a shelf in the oven at 100 6 2C for1 h or more. If the stopper has a handle then the stopper maybe placed on the shelf in the oven near the empty weighingbottle.7.2
17、Remove and place in a desiccator for at least 2 h to cool.7.3 Weigh and record to the nearest 60.001 g.7.4 Use the ground leather sample as specified in PracticeD2813 and transfer 5 6 1 g of ground leather into thepreviously weighed weighing bottle and stopper the bottle.7.5 Weigh the stoppered bott
18、le to the nearest 60.001 g andrecord.NOTE 1Since leather varies greatly in moisture content dependingupon the humidity of the surrounding atmosphere, it is essential thatweighings be made rapidly from the sample. It is further recommendedthat no weighings of samples be carried out if the humidity of
19、 theatmosphere at the balance varies by more than 620 % from the humidityconditions under which the sample was equilibrated.NOTE 2The specimens for all chemical tests to be reported on amoisture-free basis should be weighed out at the same time as the moisturespecimens.7.6 Oven DryingInsert the weig
20、hing bottle containing thesample inside the inverted stoppered cap and place on a shelfin the mechanical-convection oven at 100 6 2C for 16 612h.7.7 Recap the bottle, place in the desiccator, and cool for atleast 2 h.7.8 Weigh and record to the nearest 60.001 g.8. Calculations8.1 Calculate the perce
21、nt volatile matter (moisture) as fol-lows:Volatile matter moisture!,%5S 2 DS 2 B3 100 (1)where:S = weight, of original specimen plus bottle plus cap, g,B = weight, of empty bottle plus cap, g, andD = weight, grams, of oven-dried sample plus bottle pluscap, g.9. Report9.1 Report the percent volatile
22、matter on the as-receivedbasis for each of the two specimens and the average of the twospecimens to the nearest 0.01 %.10. Precision and Bias510.1 RepeatabilityThe average difference between tworesults obtained by the same analyst on different days willapproximate 0.2 % absolute. Two such values sho
23、uld beconsidered suspect (95 % confidence level) if they differ bymore than 0.5 % absolute.10.2 ReproducibilityThe average difference between tworesults (each the average of duplicate determinations) obtainedby analysts in different laboratories will approximate 0.3 %absolute. Two such values should
24、 be considered suspect (95 %confidence level) if they differ by more than 0.9 % absolute.10.3 This method is purely arbitrary and the bias cannot berelated to the true moisture content of the sample.11. Keywords11.1 moisture; volatile matterASTM International takes no position respecting the validit
25、y of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are 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
26、 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 International Headquarter
27、s. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you 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 i
28、s copyrighted by ASTM International, 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 aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or servicea
29、stm.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/).5The precision estimates are based on an interlaboratory study of six differenttypes of leather. One analyst in each of five laboratories performed two analyses oneach sample on successive days for a total of 60 analyses. Practice E180 was usedin developing these precision estimates. Supporting data have been filed at ASTMInternational Headquarters and may be obtained by requesting RR:D31-1004.D3790 79 (2006)12
