ASTM_D_6409_-_99_2020.pdf

Designation:D640999(Reapproved 2020)Standard Practice forColor Tests with Sheepskin Skiver1This standard is issued under the fixed designation D6409;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 practice covers making color tests of all types ofvegetable tanning extracts and of vegetable tanning materialsto determine the color imparted to tanned skins.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses after SI units areprovided for information only and are not considered standard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1517 Terminology Relating to LeatherD4901 Practice for Preparation of Solution of Liquid Veg-etable Tannin ExtractsD4905 Practice for Preparation of Solution of Solid,Pastyand Powdered Vegetable Tannin ExtractsD6405 Practice for Extraction of Tannins from Raw andSpent Materials2.2 ALCA Methods:A40 Color Tests with Sheepskin Skiver33.Terminology3.1 Definitions:3.1.1 For definitions of general leather and tanning termsused in this practice refer to Terminology D1517.3.1.2 pickled skivera sheepskin skiver that has been pick-led in a solution of salt and sulfuric acid.3.1.3 sheepskin skiverthe grain split of a de-wooledsheepskin.A pickled skiver is used for this test.3.1.4 tanninan astringent substance found in the variousparts of plants such as bark,wood,leaves,nuts,fruits,roots,etc.3.1.5 vegetable tanninsmixtures of substances(naturalproducts)obtained from plant tissues by water extractionwhich have the chemical and physical properties necessary toconvert animal hides and skins into leather.4.Summary of Practice4.1 A specimen of pickled skiver is tanned with a sample ofvegetable tanning liquor in order to determine the color whichwill be imparted to a clear,clean hide or skin that is tannedwith this tanning liquor.5.Significance and Use5.1 This practice provides a standard procedure for compar-ing the color of leather tanned with different tanning extracts ormixtures of extracts or for monitoring the color consistency oftannery liquors.6.Apparatus and Reagents6.1 Pickled Sheepskin Skiver,specially and consistentlyselected for the color test.6.2 Borax,commercial grade such as may be used in atannery.6.3 Containers,10 and 3 L capacity and made of suitablematerial to be resistant to the chemicals and materials used inthe tanning procedure employed by this practice.6.4 Acetic Acid,glacial,commercial grade.6.5 Sodium Acetate,crystal,commercial grade.6.6 Sodium Chloride,crystal,commercial grade.6.7 Shake Bottles,0.95 L(32 oz),with rubber stoppers.Thebottles shall be approximately 21.6 cm(8.5 in.)overall height1This practice is under the jurisdiction ofASTM Committee D31 on Leather andis the direct responsibility of Subcommittee D31.01 on Vegetable Leather.This testmethod has been adapted from and is a replacement for Method A40 of the OfficialMethods of the American Leather Chemists Association.Current edition approved Dec.1,2020.Published December 2020.Originallyapproved in 1999.Last previous edition approved in 2014 as D6409 99(2014).DOI:10.1520/D6409-99R20.2For 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.3Official Methods of the American Leather Chemists Association.Availablefrom the American Leather Chemists Association,University of Cincinnati,P.O.Box 210014,Cincinnati,OH 45221-0014.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1and 8.9 cm(3.5 in.)diameter.One quart canning jars(Mason-type)with plastic screw-on lids work well.6.8 Shaking Machine,rotating type,equipped to hold 0.95 L(32 oz)bottles for end-over-end agitation of hide powde