1、Designation: D7476 08 (Reapproved 2013)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 revisio
2、n, 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 estimation of degree ofsaturation of the brine content of cured (salt-prese
3、rved) hidesand skins containing 40 % or more moisture.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is t
4、heresponsibility 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:2,3D6715 Practice for Sampling and Preparation of Fresh orSalt-Preserved (Cured) Hides
5、 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 Method3. Terminology3.1 Definitions:3.1.1 The terms and definitions employed within this testmet
6、hod 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 determined. Forpurposes of calculation the ash is assumed to be equivalent tosodium chlor
7、ide 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 chloride (brine) solution at20C (68F) to estimate the percent of saturation in the br
8、inesolution in the hides or skins.NOTE 1A 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 such on aweight basis, 100 parts by weight of water will dissolve 35.9 par
9、ts (100x 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, and to slowdown autolysis by inherent enzymatic action, until the
10、y arepreserved by a tanning process.NOTE 2Osmosis 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 to osmosis; to increased fat content; or to drying outcon
11、ditions. 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 crucible by heating it for 15 min in a muffle
12、furnace set at 600 6 25C. Cool in a desiccator before use.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 charged with freshdesiccant.6.4 Analytical Balance, capable of weighing to 0.001 g
13、.6.5 Oven, forced air, capable of maintaining 100 105C.7. Reagents and Materials7.1 Distilled or de-ionized water.1This test method is under the jurisdiction ofASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved May 1, 2013. Publi
14、shed July 2013. Originally approvedin 2008. Last previous edition approved in 2008 as D7476 - 08. DOI: 10.1520/D7476-08R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
15、fer to the standards Document Summary page onthe ASTM website.3“Trade Practices for Proper Packer Cattlehide Delivery,” issued by LeatherIndustries of America and U.S. Hide, Skin the details are given in ASTM ResearchReport No. D31-1010.513.1.1 Repeatability Limit (r)Two test results obtainedwithin
16、one laboratory shall be judged not equivalent if theydiffer by more than the “r” value for that material; “r”istheinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.1
17、3.1.1.1 Repeatability limits are listed in Table 1, Table 2,and Table 3.13.1.2 Reproducibilty Limit (R)“ R” is the interval repre-senting the critical difference between two test results for thesame material, obtained by different operators using differentequipment in different laboratories.13.1.2.1
18、 Reproducibility limits were not addressed in thisstudy.13.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.13.1.4 Any judgment in accordance with statements 13.1.1would normally have an approximate 95% probability of beingcorrect, however t
19、he precision statistics obtained in this ILSmust not be treated as exact mathematical quantities which areapplicable to all circumstances and uses. The limited numberof laboratories reporting results guarantees that there will betimes when differences greater than predicted by the ILSresults will ar
20、ise, sometimes with considerably greater orsmaller frequency than the 95% probability limit would imply.The repeatability limit should be considered as a general guide,and the associated probability of 95% as only a rough indicatorof what can be expected.13.2 BiasAt the time of the study, there was
21、no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.13.3 The precision statement was determined through sta-tistical examination of the analytical results from onelaboratory, on samples from five different material lots.13
22、.4 To judge the equivalency of two test results, it isrecommended to choose the material closest in characteristicsto the test material.14. Keywords14.1 ash; brine saturation; curing; hide; moistureskinASTM International takes no position respecting the validity of any patent rights asserted in conn
23、ection 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 respons
24、ible 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 will receive careful c
25、onsideration 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, 10
26、0 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 through the ASTM w
27、ebsite(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).5Available from ASTM International Headquarters. Reprinted with permissionof the Leather Industries of America and the Leather Research Laboratory of theUniversity of
28、 Cincinnati.TABLE 1 Moisture (%)Material AveragexRepeatability Stan-dard DeviationsrRepeatability Limitr1 40.54 1.35 3.782 41.55 0.69 1.923 45.56 1.64 4.594 43.92 1.46 4.105 46.55 0.48 1.35TABLE 2 Ash (%)Material AveragexRepeatability Stan-dard DeviationsrRepeatability Limitr1 14.47 0.28 0.772 15.00 0.79 2.223 12.14 0.01 0.024 13.55 0.06 0.165 11.10 0.05 0.14TABLE 3 Brine Saturation (%)Material AveragexRepeatability Stan-dard DeviationsrRepeatability Limitr1 89.5 4.9 13.92 98.0 2.8 7.93 74.0 2.8 7.94 86.0 2.8 7.95 67.0 1.4 4.0D7476 08 (2013)3
