1、Designation: D4655 95 (Reapproved 2017)Standard Test Methods forSulfates in Leather (Total, Neutral, and Combined Acid)1This standard is issued under the fixed designation D4655; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test methods are i
3、ntended for use in determiningthe total, neutral, and combined acid sulfate in mineral-tannedleather.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
4、 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.1.4 This international standard was developed in accor-dance with internationally recogniz
5、ed 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:2D2813 Practice for Sampl
6、ing Leather for Physical andChemical TestsD4654 Test Method for Sulfate Basicity in Leather3. Significance and Use3.1 These test methods are used to determine the basicity ofleather when used in accordance with Test Method D4654.4. Apparatus4.1 Volumetric Flask, 250 mL.4.2 Filter paper, ashless, fin
7、e grained and porcelain crucible.4.3 Crucible, Gooch, with porous porcelain filter (optional).5. Reagents5.1 Ammonium Hydroxide Solution, (0.1 N)7 mL/L re-agent grade concentrate NH4OH. Optional: Potassium dihydro-gen phosphate, 0.1 molar solution (13.6 g/L KH2PO4)orsodium dihydrogen phosphate, 0.1
8、molar solution (13.8 g/ LNaH2PO4-H2O).5.2 Hydrochloric Acid Solution, (1.5 N)125 mL/L reagentgrade concentrate hydrochloric acid.5.3 Barium Chloride Solution(BaCl22H2O), 1 %.5.4 Sodium Hydroxide Solution, 0.01 N, 0.4 g/L.5.5 Mixed Indicator, consisting of 60 mL of a 0.1 % solutionof methyl red and 4
9、0 mL of a 0.1 % solution of methylene blue,both in 95 % alcohol.6. Sampling, Test Specimens, and Test Units6.1 The specimen for each determination shall consist of 1g leather from the composite sample (See Practice D2813).6.2 Two specimens from the composite sample shall betested for each determinat
10、ion.7. Procedure7.1 Total SulfatesWeigh the specimen to the nearest mil-ligram and record the value as W1. Transfer the specimen to a250-mL volumetric flask and add 200 mL of 0.1 N ammoniumhydroxide or 0.1 molar potassium or sodium dihydrogenphosphate solution. Immerse the flask up to the neck in a
11、bathof boiling water. Thoroughly wet all products by swirlingoccasionally. After 2 h cool the flask to room temperature, andmake up to volume with distilled water, shake, and withoutdelay filter through a folded filter paper. Discard the first 20 to25 mL of the filtrate. Pipette 200 mL of the filtra
12、te into a 600mL beaker and add about 20 mL of 1.5 N hydrochloric acid.Heat the solution to boiling and while boiling and stirring thesolution, add 20 mL of a 1 % solution of barium chloridedropwise. Keep the covered beaker in a warm place at least for2 h and preferably overnight.7.1.1 Filter the pre
13、cipitate through a fine grained ashlessfilter paper and wash with hot water until free from chloride. Aweighed Gooch crucible or a weighed porous crucible may be1These test methods are under the jurisdiction of ASTM Committee D31 onLeather and are the direct responsibility of Subcommittee D31.06 on
14、ChemicalAnalysis. This test method was developed in cooperation with theAmerican LeatherChemists Assn. (Method D201956).Current edition approved April 1, 2017. Published April 2017. Originallyapproved in 1987. Last previous edition approved in 2012 as D465595 (2012).DOI: 10.1520/D4655-95R17.2For ref
15、erenced 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, Wes
16、t 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 Tr
17、ade Organization Technical Barriers to Trade (TBT) Committee.1used as an alternative for the filtration. Transfer the paper withthe precipitate to a weighed crucible and ignite gently, eitherover a gas burner or in a muffle oven at 900C for 1 h. Cool thecrucible in a desiccator, weigh, and record th
18、e value of theBaSO4as W2.7.2 Neutral SulfatesWeigh the specimen to the nearestmilligram and record the value as W3. Transfer the specimen toa 250-mL volumetric flask and add 200 mL of distilled water.Immerse the flask up to the neck in boiling water. Thoroughlywet all particles by swirling occasiona
19、lly. After 2 h cool flaskto room temperature, make up to volume with distilled water,shake and without delay filter through a folded filter. Discardthe first 20 to 25 mLof the filtrate. Pipette 200 mLof the filtrateinto a 600-mL beaker and titrate with 0.01 N sodiumhydroxide, using a few drops of th
20、e methyl red/methylene blueindicator. Record the results as mL 0.01 N NaOH. Afteraddition of 4 to 5 mL of 1.5 N hydrochloric acid, heat thesolution to boiling. While boiling and stirring the solution, add10 mL of a 1 % barium chloride solution dropwise. Keep thecovered beaker in a warm place at leas
21、t for 2 h and preferablyovernight.7.2.1 Follow the directions for filtration given in 7.1.1.Record the value of the BaSO4as W4.8. Calculation of Results8.1 Calculate the total sulfate content of the specimen asfollows:% total sulfate SO4! 5 W23.4115/W13250/200 3100 (1)where:W1= the weight of the spe
22、cimen, andW2= the weight of the BaSO4.8.2 Calculate the neutral sulfate content of the specimen asfollows:% neutral sulfate SO4! 5 W43 .4115 2 N (2)3A 3.048)/W33250/250 3100where:W3= the weight of the specimen,W4= the weight of the BaSO4,A = the millilitre of standard NaOH, andN = the normality of t
23、he standard NaOH.8.3 Calculate the combined acid sulfate content of thespecimen as follows:% combined acid sulfate SO4! (3)5 % total sulfate 2 % neutral sulfate.8.3.1 The total, neutral and combined acid sulfates in thesample for test shall be the average of the test results obtainedfrom the specime
24、ns tested.9. Report9.1 Unless otherwise specified in the detail specification, theresults shall be reported to the nearest 0.1 %.10. Precision and Bias10.1 This test method is adopted from the procedures of theAmerican Leather ChemistsAssociation where it has long beenin use and where it was approve
25、d for publication before theinclusion of precision and bias statements were mandated. Theoriginal interlaboratory test data is no longer available. Theuser is cautioned to verify by the use of reference material ifavailable that the precision and bias of this test method isadequate for the contempla
26、ted use.11. Keywords11.1 combined acid sulfate; mineral tanned leather; neutralsulfates; total sulfatesASTM 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 d
27、etermination 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 responsible technical committee and must be reviewed every five years andif not revised, either reapproved
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29、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, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprin
30、ts (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 website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 95 (2017)2
