1、Designation: D2876 00 (Reapproved 2010)Standard Test Method forWater-Soluble Matter of Vegetable-Tanned Leather1This standard is issued under the fixed designation D2876; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last revision. 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 water-soluble materials in all types of vegetable-tanned leathers. Th
3、istest method does not apply to wet blue.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of th
4、e 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:2D3495 Test Method for Hexane Extraction of Leather3. Summary of Test Method3.1 The test method gives the am
5、ount of water-solublematter extracted from the leather at 35C by 1 L of water in 3h. The leather is first freed of hexane-extractable material byextraction with hexane and leaving at ambient temperature inan exhaust hood to remove the hexane.4. Significance and Use4.1 The test method is useful for d
6、etermining the water-soluble materials in vegetable-tanned leathers.4.2 The water-soluble matter includes the soluble nontan-ning components of the tanning materials used, sugars andmaterials of a similar nature, and inorganic compounds such asEpsom salts, Glaubers salts, borax, and other soluble sa
7、ltsadded during curing and tannery processing.5. Apparatus5.1 Crystallizing Dish, borosilicate glass, 50 mm tall, 70mm in outside diameter, and weighing between 30 and 39 g.5.2 Extractor, Reed-Churchill Type3The extraction tubeshall have an internal diameter of 45 6 2 mm and a length of233 6 10 mm.
8、See Fig. 1.5.3 Water Bath, equipped to control the temperature at 35 60.5C.5.4 Circulating Air Oven, capable of maintaining a tempera-ture of 99 6 1C.6. Test Specimen6.1 The specimen shall consist of the 5-g leather sample thathas been extracted with hexane as directed in Test MethodD3495.Any deviat
9、ion from this sample size should be includedwith the analytical results.7. Procedure7.1 Insert a plug of cotton or glass wool in the extractiontube before the specimen is added. Place the specimen in theextraction tube, slurry, and extract at 35C by adjusting theflow to such a rate as to give 1 L of
10、 extract in 3 h. Cool theextract to 23C, adjust to volume, and thoroughly mix.7.2 If the extract is clear, pipet 100 mL into a taredcrystallizing dish, evaporate and dry in a circulating air oven at99 6 1C for 16 to 18 h, transfer to a desiccator, cool, andweigh.7.3 If the extract is not clear, filt
11、er it. During this andsubsequent operations, keep funnels and containers covered toprevent changes due to evaporations. Carry out all operationsat an ambient temperature of 23 to 25C. Place a 215-mmdiameter filter paper,4pleated so that it contains 32 evenlydivided creases, into a 125-mL funnel. To
12、2.0 g of kaolin (seeNote 1) in a clean glass container add 25 mL of the extract and1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. Thistest method was developed in cooperation with the American
13、Leather ChemistsAssn. (Standard Method B81954).Current edition approved April 1, 2010. Published May 2010. Originallyapproved in 1970. Last previous edition approved in 2005 as D287600 (2005).DOI: 10.1520/D2876-00R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact AST
14、M Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reed, H. C. and Churchill, J. B., “An Extractor for Water Soluble in Leather,”Journal of the American Leather Chemists Association, JALCA, Vol
15、14, 1919, p.137.4The sole source of supply of approved filter paper (C.S. and S. No. 610) fortannin determinations known to the committee at this time is Carl Schleicher andSchuell Co., Keene, NH. If you are aware of alternative suppliers, please providethis information to ASTM headquarters. Your co
16、mments will receive carefulconsideration at a meeting of the responsible technical committee1which you mayattend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.FIG. 1 Reed-Churchill Type ExtractorD2876 00 (2010)2stir the mixture to
17、a smooth paste. Add a further 200 mL of theextract and again stir the mixture to a uniform suspension. Pourthe suspension onto the pleated paper in the funnel and collectthe filtrate in the container in which the solution and kaolinwere mixed. When 40 mL of the filtrate have been collected,swirl it
18、to pick up kaolin remaining in the container, and returnit to the funnel. Repeat collecting and repouring 40 mL of thefiltrate onto the paper in the funnel as many times as possiblefor 1 h. Siphon the solution out of the filter without disturbingthe kaolin film and discard it. Refill the paper with
19、225 mL ofthe extract, disturbing the kaolin film as little as possible bypouring into the center of the cone. When 40 mL of the filtratehave passed through, collect the next portion in a clear, dryglass container and, when about 125 mL have been collected,remove the container from beneath the funnel
20、. Check this 125mL for clarity and if not clear reject it and rerun thedetermination using a new filter.NOTE 1Only approved kaolin should be used.5When 1.0 g issuspended in 100 mL of distilled water for 5 min, the suspension shallhave a pH between 4.5 and 6.0. When 2.0 g are shaken with 100 mL ofdis
21、tilled water for 10 min and the mixture filtered, 100 mL of clear filtrateshall leave less than 0.001 g of residue when evaporated and dried in aplatinum dish.8. Calculation8.1 Calculate the percentage soluble material in the leatheras follows:Water2soluble material, % 5 W22 W1!/W3# 3 1000 (1)where:
22、W1= weight of crystallizing dish,W2= weight of crystallizing dish and residue, andW3= weight of the leather specimen.9. Precision and Bias69.1 The precision of the test method is largely limited bylack of homogeneity of the sample in a complex material suchas leather. It will also vary with water so
23、lubles content.9.1.1 At the 95 % confidence level, duplicate determina-tions by the same operator should not differ more than 0.6 %water solubles.9.1.2 At the 95 % confidence level, the average of duplicatedeterminations in each of two laboratories should not differ bymore than 1.0 % water solubles.
24、9.2 Inasmuch as all leathers contain an unknown amount ofnatural or inherent water solubles, no meaningful statement canbe made with respect to bias.10. Keywords10.1 leather; vegetable-tanned leather; water-soluble matterASTM International takes no position respecting the validity of any patent righ
25、ts 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 to revision at any
26、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 Headquarters. Your comments wil
27、l 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 is copyrighted by AST
28、M 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 serviceastm.org (e-mail); or
29、 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 sole source of supply of the approved kaolin known to the committee atthis time is Arthur H. Thomas Co., Philadelphia, PA. If you are aware of
30、 alternativesuppliers, please provide this information to ASTM headquarters. Your commentswill receive careful consideration at a meeting of the responsible technicalcommittee1which you may attend.6Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D31-1001.D2876 00 (2010)3
