1、Designation:D747608(Reapproved 2020)Standard Test Method forBrine Saturation Value of Cured(Salt-Preserved)Hides andSkins1This standard is issued under the fixed designation D7476;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the y
2、ear 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 estimation of degree ofsaturation of the brine content of cured(salt-preserved)hidesand
3、skins containing 40%or more moisture.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standard does not purport to address all
4、 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 acco
5、r-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 St
6、andards:2,3D6715 Practice for Sampling and Preparation of Fresh orSalt-Preserved(Cured)Hides and Skins for Chemical andPhysical TestsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Meth
7、od3.Terminology3.1 Definitions:3.1.1 The terms and definitions employed within this testmethod are commonly used in normal laboratory practice andrequire no special comment.4.Summary of Test Method4.1 The moisture(volatile matter by oven drying)and ashcontent of a composite hide or skin sample are d
8、etermined.Forpurposes of calculation the ash is assumed to be equivalent tosodium chloride and the moisture is assumed to be equivalentto water.The percent ratio of ash to moisture is calculated.Thisratio times 100 is divided by 35.9(which is the percent salt tomoisture ratio in a saturated sodium c
9、hloride(brine)solution at20C(68F)to estimate the percent of saturation in the brinesolution in the hides or skins.NOTE1A saturated solution of sodium chloride at 20C(68F)contains 26.4%by weight of NaCl.Therefore,in 100 g of that saturatedsolution only 73.6 g(100 26.4 g)is contributed by water.As suc
10、h on aweight basis,100 parts by weight of water will dissolve 35.9 parts(100 x 26.4)/73.6 by weight of NaCl.5.Significance and Use5.1 This test method is intended to evaluate whether suffi-cient salt(NaCl)has been retained by the hides or skins to slowdown degradation by bacterial(enzymatic)action,a
11、nd to slowdown autolysis by inherent enzymatic action,until they arepreserved by a tanning process.NOTE2Osmosis occurs during brine curing because moisture isdrawn out by salt through the epidermis.4Low moisture(40%)in thehides does not necessarily indicate poor cure.A hide may have lowmoisture due
12、to osmosis;to increased fat content;or to drying outconditions.In all instances the hides would still show adequate cure if themoisture was saturated to approximately 85%salt,because the ash:moisture ratio would be adequate.6.Apparatus6.1 Crucible,30 to 50 mL,high-form,platinum or porce-lain.Prepare
13、 crucible by heating it for 15 min in a mufflefurnace set at 600 6 25C.Cool in a desiccator before use.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved April 1,2020.Published April
14、 2020.Originallyapproved in 2008.Last previous edition approved in 2013 as D7476 08(2013).DOI:10.1520/D7476-08R20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandardsvolume information,refer to the stan
15、dards Document Summary page onthe ASTM website.3“Trade Practices for Proper Packer Cattlehide Delivery,”issued by LeatherIndustries of America and U.S.Hide,Skin&Leather Association(printed May1985).4JALCA,1963,p.143.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA
16、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.6.2 Electric Muffle Furnace,with controller or rheostat andpyrometer,capable of maintaining a temperature of 650 625C.6.3 Desiccator,of appropriate size and charg
