1、Designation: D 7476 08Standard Test Method forBrine Saturation Value of Cured (Salt-Preserved) Hides andSkins1This standard is issued under the fixed designation D 7476; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast 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 s
3、kins 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 theresponsibility
4、 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:2,3D 6715 Practice for Sampling and Preparation of Salt Pre-served (Cured) Hides and Skins for Chemica
5、l and PhysicalTestsE 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 691 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 testmethod are commonly use
6、d 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 chloride and the moisture
7、 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 brinesolution in the h
8、ides 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 parts (100x 26.4)/73.6
9、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 they arepreserved by a
10、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 outconditions. In all inst
11、ances 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 mufflefurnace set at 600 6
12、 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.6.5 Oven, forced ai
13、r, capable of maintaining 100 105C.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 Sept. 1, 2008. Published September 2008.2For referenced ASTM standards, visit the ASTM website, w
14、ww.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.3“Trade Practices for Proper Packer Cattlehide Delivery,” issued by LeatherIndustries of America and U.S. Hide, Skin t
15、he details are given in ASTM ResearchReport No. D31-1010.513.1.1 Repeatability Limit (r)Two test results obtainedwithin 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 testresu
16、lts for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.13.1.1.1 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 re
17、sults for thesame material, obtained by different operators using differentequipment in different laboratories.13.1.2.1 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 E 177.13.1.4 Any ju
18、dgment in accordance with statements 13.1.1would normally have an approximate 95% probability of beingcorrect, however the precision statistics obtained in this ILSmust not be treated as exact mathematical quantities which areapplicable to all circumstances and uses. The limited numberof laboratorie
19、s reporting results guarantees that there will betimes when differences greater than predicted by the ILSresults will arise, 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 asso
20、ciated probability of 95% as only a rough indicatorof what can be expected.13.2 BiasAt the time of the study, there was 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 throug
21、h sta-tistical examination of the analytical results from one labora-tory, on samples from five different material lots.13.4 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; cu
22、ring; hide; moisture; skinASTM International takes no position respecting the validity of any patent rights asserted in connection 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 infrin
23、gement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible 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
24、 or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration 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
25、 known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 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
26、 ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).5Available from ASTM International Headquarters. Reprinted with permissionof the Leather Industries of America and the Leather Research Laboratory of theUn
27、iversity of Cincinnati.TABLE 1 Moisture (%)Material AveragexRepeatabilityStandard 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 AveragexRepeatabilityStandard 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 AveragexRepeatabilityStandard 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 4.0D7476083
