1、Designation: D 2876 00 (Reapproved 2005)Standard Test Method forWater-Soluble Matter of Vegetable-Tanned Leather1This standard is issued under the fixed designation D 2876; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. 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 water-soluble materials in all types of vegetable-tanned leathers.
3、 Thistest method does not apply to wet blue.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 standard to establish appro-priate safety and health practices and determine the applica-bility of regulat
4、ory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 3495 Test Method for Hexane Extraction of Leather23. Summary of Test Method3.1 The test method gives the amount of water-solublematter extracted from the leather at 35C by 1 L of water in 3h. The leather is first freed of hexan
5、e-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 determining the water-soluble materials in vegetable-tanned leathers.4.2 The water-soluble matter includes the soluble no
6、ntan-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 saltsadded during curing and tannery processing.5. Apparatus5.1 Crystallizing Dish, borosilicate glass, 50 mm tall, 70mm i
7、n 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. See Fig. 1.5.3 Water Bath, equipped to control the temperature at 35 60.5C.5.4 Circulating Air Oven, capable of maintain
8、ing 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 MethodD 3495. Any deviation from this sample size should beincluded with the analytical results.7. Procedure7.1 Insert a plug of cotton or gla
9、ss 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 extract in 3 h. Cool theextract to 23C, adjust to volume, and thoroughly mix.7.2 If the extract is clear, pipet 100 m
10、L 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, filter it. During this andsubsequent operations, keep funnels and containers covered toprevent changes due to evaporations
11、. 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 2.0 g of kaolin (seeNote 1) in a clean glass container add 25 mL of the extract andstir the mixture to a smooth paste.
12、 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 kaolin1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is
13、the direct responsibility of Subcommittee D31.01 on Vegetable Leather. Thistest method was developed in cooperation with the American Leather ChemistsAssn. (Standard Method B 81954).Current edition approved Sept. 1, 2005. Published September 2005. Originallyapproved in 1970 as D 287670T. Last previo
14、us edition approved in 2000 asD 287600.2Annual Book of ASTM Standards, Vol 15.04.3Reed, H. C. and Churchill, J. B., “An Extractor for Water Soluble in Leather,”Journal of the American Leather Chemists Association, JALCA, Vol 14, 1919, p.137.4The sole source of supply of approved filter paper (C.S. a
15、nd 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 comments will receive carefulconsideration at a meeting of the responsible te
16、chnical 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 ExtractorD 2876 00 (2005)2were mixed. When 40 mL of the filtrate have been collected,swirl it to pick up kaolin remainin
17、g 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 225 mL ofthe extract, dist
18、urbing 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. Check this 125mL for cla
19、rity 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 ofdistilled water for 10 min an
20、d 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:W1= weight of crystallizin
21、g 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 solubles content.9.1.1 At th
22、e 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.9.2 Inasmuch as all leathe
23、rs 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 rights asserted in connection
24、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 time by the responsible te
25、chnical 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 will receive careful consider
26、ation 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 ASTM International, 100 Barr
27、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 through the ASTM website(
28、www.astm.org).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 alternativesuppliers, please provide this information to ASTM headquarters. Your commentswill receive careful consideration at a meeting of the responsible technicalcommittee1which you may attend.6The precision and bias statements are based on data filed at ASTMHeadquarters as RR: D31-1001.D 2876 00 (2005)3
