ASTM_D_2876_-_00_2016.pdf

Designation:D287600(Reapproved 2016)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 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.Thistest 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 the 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 amount 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 determining 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 saltsadded 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.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 deviation 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 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,filter 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 2.0 g of kaolin(see1This 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 Leather ChemistsAssn.(Standard Method B81954).Current edition approved Sept.1,2016.Published September 2016.Originallyapproved in 1970.Last previous edition approved in 2010 as D287600(2010).DOI:10.1520/D2876-00R16.2For 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 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 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 comments will receive carefulconsideration at a meeting of the responsible technical committee1which you mayattend.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 FIG.1 Reed-Churchill Type ExtractorD2876 00(2016)2 Note 1)in a clean glass container add 25 mL of the extract andstir the mixture to 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,swi