1、Designation: D3790 79 (Reapproved 2012)D3790 17Standard 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,
2、the year 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 U.S. Department of Defense.1. Scope1.1 This test method cov
3、ers the determination of volatile matter (moisture) in all types of leather.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with
4、its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardi
5、zationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D2813 Practice for Sampling Leather for Physical and
6、 Chemical TestsE180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals(Withdrawn 2009)33. 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, coole
7、d,and reweighed. The loss in weight represents the volatile matter.4. Significance and Use4.1 The result obtained by this test is normally considered to be the moisture content of the leather sample. This result is usedto correct all other chemical tests to a moisture-free basis.4.2 Materials that a
8、re volatile under these conditions, other than water, may be present in the leather, although their amount inany normal leather would be expected to be a very small percentage of the total volatile matter.4.3 Under the conditions of this test, certain materials in leather, such as protein fiber and
9、chromium tanning salts, may retainmoisture. Other materials, such as tannins and oils, may be oxidized. Both of these effects produce negative errors in the moisturedetermination.4.4 The amount of volatile matter (moisture) released by a given leather varies with (a) degree of grinding of the sample
10、, (b)weight of sample taken, (c) temperature and time of the oven drying, (d) shape of the weighing container, and (e) type of oven(gravity versus mechanical convection) used.4.5 Because of the above unknown errors, the result of this test is a purely arbitrary value for the moisture content of the
11、sample.It is, therefore, essential that the method be followed exactly in order to obtain reproducible results among laboratories. This isparticularly true if other chemical analytical tests being performed on the same sample are reported on the moisture-free basis.1 This test method is under the ju
12、risdiction of ASTM Committee D31 on Leather and is the direct responsibility of Subcommittee D31.06 on Chemical Analysis.Current edition approved April 1, 2012April 1, 2017. Published April 2012May 2017. Originally approved in 1979. Last previous edition approved in 20062012 asD3790 - 79(2006)(2012)
13、.1. DOI: 10.1520/D3790-79R12.10.1520/D3790-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document i
14、s not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as approp
15、riate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Apparatus5.1 Weighing Bottle3, glass, low-form, cylindrical
16、with a ground-glass stopper of standard taper. The bottle shall have 70 6 5mm inside diameter, and 33 6 3 mm overall height.5.2 Oven, mechanical-convection draft capable of setting at 100C, 100 C, with a thermoregulator system capable of holdingoven temperature within 6 2C62 C of set point. A thermo
17、meter accurate to 60.2C 60.2 C should be used to check andmonitor the oven set point.5.3 Balance, capable of weighing up to 100 g with an accuracy of 60.001 g.5.4 Desiccator, any convenient form or size, using any normal desiccating agent such as calcium sulfate, calcium chloride, orsilica gel.6. Sa
18、mpling6.1 The leather shall be sampled in accordance with Practice D2813.7. Procedure7.1 Insert the empty weighing bottle inside the inverted stoppered cap and place on a shelf in the oven at 100 6 2C 2 C for1 h or more. If the stopper has a handle then the stopper may be placed on the shelf in the
19、oven near the empty weighing bottle.7.2 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 Practice D2813 and transfer 5 6 1 g of ground leather into the previouslyweighed weighing bottle and stoppe
20、r the bottle.7.5 Weigh the stoppered bottle to the nearest 60.001 g and record.NOTE 1Since leather varies greatly in moisture content depending upon the humidity of the surrounding atmosphere, it is essential that weighingsbe made rapidly from the sample. It is further recommended that no weighings
21、of samples be carried out if the humidity of the atmosphere at the balancevaries by more than 620 % from the humidity conditions under which the sample was equilibrated.NOTE 2The specimens for all chemical tests to be reported on a moisture-free basis should be weighed out at the same time as the mo
22、isture specimens.7.6 Oven DryingInsert the weighing bottle containing the sample inside the inverted stoppered cap and place on a shelf in themechanical-convection oven at 100 6 2C 2 C for 16 6 12 h.7.7 Recap the bottle, place in the desiccator, and cool for at least 2 h.7.8 Weigh and record to the
23、nearest 60.001 g.8. Calculations8.1 Calculate the percent volatile matter (moisture) as follows:Volatile matter moisture!,%5S 2DS 2B 3100 (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
24、plus cap, g.9. Report9.1 Report the percent volatile matter on the as-received basis for each of the two specimens and the average of the twospecimens to the nearest 0.01 %.10. Precision and Bias410.1 RepeatabilityThe average difference between two results obtained by the same analyst on different d
25、ays will approximate0.2 % absolute. Two such values should be considered suspect (95 % confidence level) if they differ by more than 0.5 % absolute.3 Weighing bottles that have been found to be satisfactory are the Kimble Glass Co. No. 15166 and 15165 with 71/15 standard-taper caps and are available
26、 from mostlaboratory supply houses.4 The precision estimates are based on an interlaboratory study of six different types of leather. One analyst in each of five laboratories performed two analyses on eachsample on successive days for a total of 60 analyses. Practice E180 was used in developing thes
27、e precision estimates. Supporting data have been filed at ASTM InternationalHeadquarters and may be obtained by requesting RR:D31-1004.D3790 17210.2 ReproducibilityThe average difference between two results (each the average of duplicate determinations) obtained byanalysts in different laboratories
28、will approximate 0.3 % absolute. Two such values should be considered suspect (95 % confidencelevel) if they differ by more than 0.9 % absolute.10.3 This method is purely arbitrary and the bias cannot be related to the true moisture content of the sample.11. Keywords11.1 moisture; volatile matterAST
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32、n 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 States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or a
33、t 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ The last approved version of this historical standard is referenced on www.astm.org.D3790 173
