1、Designation: D 6076 03Standard Test Method forShrinkage Temperature of Leather1This standard is issued under the fixed designation D 6076; 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 paren
2、theses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the determination of the shrink-age temperat
3、ure of all types of leather. The heating medium iswater when the shrinkage temperature is at or below 98C. Theheating medium is a glycerine-water solution when the shrink-age temperature is above 98C.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses
4、 are for informationonly.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 and health practices and determine the applica-bility of regulatory limitations pri
5、or to use.2. Referenced Documents2.1 ASTM Standards:2D 1517 Terminology Relating to Leather3. Terminology3.1 DefinitionsFor definitions of general leather termsused in this test method, refer to Terminology D 1517.3.2 Definitions of Terms Specific to This Standard:3.2.1 shrinkto contract or become s
6、maller.3.2.2 shrinkagethe temperature at which noticeableshrinkage occurs when a leather specimen is gradually heatedin an aqueous medium.4. Summary of Test Method4.1 A leather specimen is thoroughly soaked in the aqueousmedium that will be used to heat the specimen for this testmethod. This specime
7、n is then fastened between two clamps(one fixed and one movable) and immersed in the aqueousmedium. The aqueous medium is gradually heated until thespecified temperature is reached without shrinkage or untilshrinkage is indicated by a deflection of the dial needle whichis attached to the movable cla
8、mp.5. Significance and Use5.1 This test method is designed to determine the tempera-ture at which a thoroughly wetted leather specimen experiencesshrinkage. In this test method, shrinkage occurs as a result ofhydrothermal denaturation of the collagen protein moleculeswhich make up the fiber structur
9、e of the leather. The shrinkagetemperature of leather is influenced by many different factors,most of which appear to affect the number and nature ofcrosslinking interactions between adjacent polypeptide chainsof the collagen protein molecules. The value of the shrinkagetemperature of leather is com
10、monly used as an indicator of thetype of tannage or the degree of tannage, or both, of thatparticular leather (especially for the more hydrothermallystable tannages such as chrome tannage).6. Apparatus6.1 Stand, for supporting the testing equipment.6.2 Indicating Device, either of the two devices li
11、sted asfollows:6.2.1 Theis Shrinkage Meter Diala dial indicator having aface divided into 360 to 380, with one revolution of the dialhand corresponding to 12.7 mm (0.5 in.) of specimen move-ment, and with leeway for four revolutions of the dial hand.36.2.2 AGD (American Gage Design) Dial IndicatorAm
12、echanical device capable of registering on a scale a readingof the shrinkage or swelling movement of the specimen in aratio of at least 25 units of dial movement (or greater) to 1 unitof specimen movement, and shall accurately detect by move-ment of the dial needle the point at which shrinkage begin
13、s.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.07 on Physical Properties. Thistest method was developed from Federal Test Method Standard No. 311, Method7011.1, in cooperation with the U.S. Defense Personnel Support
14、Center, Directorateof Clothing and Textiles, Philadelphia, PA and the U.S. Army Natick Research,Development and Engineering Center, Natick, MA.Current edition approved Oct. 1, 2003. Published December 2003. Originallyapproved in 1997. Last previous edition approved in 1997 as D 6076-97.2For referenc
15、ed 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.3A shrinkage meter apparatus setup meeting these specific requirements was
16、formerly available from the Arthur H. Thomas Co., Philadelphia, PA. The minimumnumber of apparatus setups required for an order makes the cost of new apparatusof this type prohibitive. Used apparatus of this type may still be available fromtanneries or laboratories that have gone out of business or
17、from used equipmentdealers.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.The indicator shall have a spindle capable of attachment to thespecimen and to the adjustable weight assembly.46.3 Immersion Heater, 250 to 500 W, with a heat
18、ing elementnot longer than 140 mm (512 in.) and a depth of immersion notin excess of 152 mm (6 in.).6.4 Variable Speed Stirrer, with small blades.6.5 Spring-loaded Clamps(alligator type), two, mountedvertically one above the other and sufficiently far apart forgripping the full width of the specimen
19、 at the ends. The bottomclamp shall be fastened to the end of a U-shaped rod that canbe turned sideways. The upper clamp shall be movablesideways as well as up and down.6.6 Metal Supporting Plate, with apertures for the stirrer,thermometer, immersion heater, and the rod fastened to theupper specimen
20、 clamp.6.7 Variable Transformer, capable of controlling the rate ofheating (3 to 5C/min) of the aqueous medium and capable ofmaintaining a temperature of 98 6 0.5C.6.8 Thermometer, with a white background, a scale from 1or 10C to +101 or +110C or +150C, graduated in 1C, andwith 60.5C tolerance.6.9 T
21、all-form 1L Beaker, for holding the aqueous heatingmedium.6.10 Lead Shot.6.11 Indicating Device, attached to the upper (movable)clamp and equipped with an adjustable weight assemblymounted over a pulley. The weight assembly shall consist of asmall bottle (with a lid) containing lead shot that shall
22、beattached to the string running over the pulley. The weightassembly shall be approximately 178 g to counterbalance theweight of the clamp, to overcome any inertia or friction of theindicating device, and to maintain the specimen under a slighttension. The weight shall be adjusted accordingly, so th
23、at it willnot cause an elongation (prior to shrinkage) or more than 10 %.The device shall register a ratio of 25:1 (or greater) between thescale reading and the shrinkage or elongation of the specimen,and shall accurately detect the point at which shrinkage begins.6.12 Metal Die, for cutting the spe
24、cimen to the requireddimensions.6.13 Suction Flask,1L.6.14 Nylon String, for connecting the upper clamp (or therod connected to the upper clamp) to the weight assembly andpassing over the pulley on the indicating dial.7. Reagents7.1 Glycerine-water SolutionWhen glycerine-water me-dium is specified f
25、or use (that is, when the shrinkage tempera-ture is specified or expected to be greater than 98C) thesolution shall consist of 75 parts glycerine to 25 parts water.The specific gravity of the solution shall be adjusted to 1.19 at23C. The glycerine-water solution shall not be heated over112C.8. Test
26、Specimen8.1 The test specimen for the test shall be a rectangle ofleather 76.0 6 0.5 mm (3.0 in.) in length by 12.5 6 0.5 mm(0.5 in.) in width, die cut from the sample unit of leather withthe long dimension perpendicular to the backbone line.8.2 Unless otherwise specified in the material specificati
27、on,one test specimen shall be tested from each sample unit.9. Procedure9.1 When shrinkage temperatures at or below 98C arespecified, the heating medium shall be water.9.2 When shrinkage temperatures over 98C are specified,the heating medium shall be the glycerine-water solutiondescribed in 7.1.9.3 P
28、repare the specimens as follows prior to mounting inthe holding clamps. Place more than 15 specimens in a 1Lsuction flask containing approximately 300 mL of the requiredheating medium at room temperature. Stopper the flask andapply a vacuum for 15 to 60 s and then release for 15 to 60 s.Continue an
29、intermittent vacuum until all the specimens settleto the bottom of the flask. Gently shake the flask each time thevacuum is released to prevent specimens that are ready to sinkfrom being entangled with other specimens. One hour after thelast release of vacuum, remove the first specimen from theflask
30、 and mount in the shrinkage meter. Keep the otherspecimens in the flask (containing the heating medium) untiltested. The time from when the first specimen is removed fromthe suction flask and the testing of the last specimen iscompleted shall not exceed 6 h.9.4 Fasten the specimen in the two clamps
31、of the shrinkagemeter and completely immerse in the heating medium, whichhas been preheated to 50 6 5C. Adjust the indicator to areference point on the dial by taking the slack out of thespecimen. If the specimen should lengthen before it contractsas the temperature of the heating medium is increase
32、d at a rateof 3 to 5C/min, the reference point at which the indicatorcomes to rest shall be the new reference point for observingshrinkage.9.5 When a shrinkage temperature of 98C or below isspecified, increase the temperature of the water heating me-dium at the rate of 3 to 5C/min until the specimen
33、 shrinks oruntil the specified shrinkage temperature is reached.9.6 When the material specification requires the specimennot to shrink when subjected to a temperature of 98 6 0.5Cfor 30 s, increase the temperature of the water heating mediumat the rate of 3 to 5C/min until the temperature reaches 98
34、C.Keep the temperature at 98 6 0.5C for 30 s by adjusting thetransformer. If the specimen shrinks during the 30s period,record the number of seconds that elapse between reaching thetemperature of 98C and shrinkage of the specimen. If thespecimen shrinks before the temperature reaches 98C, recordthe
35、temperature at which shrinkage occurs.9.7 When a shrinkage temperature of over 98C is specified,increase the temperature of the glycerine-water heating me-dium at the rate of 3 to 5C/min until the specimen shrinks oruntil a maximum temperature at 112C is reached.10. Report10.1 Report the following i
36、nformation:4The sole source of supply of the apparatus known to the committee at this timeis B.C. Ames Co., Lexington St., Waltham, MA 02254. If you are aware ofalternative suppliers, please provide this information to ASTM Headquarters. Yourcomments will receive careful consideration at a meeting o
37、f the responsibletechnical committee, which you may attend.D 6076 03210.1.1 When the specified shrinkage temperature is 98C orless:10.1.1.1 If the specimen shrinks before the temperaturereaches 98C, report the temperature at which shrinkage occursto the nearest 1C, and10.1.1.2 If the specified tempe
38、rature is reached withoutshrinkage.10.1.2 When the specification requires the specimen to notshrink for 30 s at 98C:10.1.2.1 If the specimen shrinks before the temperaturereaches 98C, report the temperature at which shrinkage occursto the nearest 1C,10.1.2.2 If the specimen shrinks during the 30s in
39、terval,report the number of seconds that elapsed between reaching thetemperature of 98C and shrinkage of the specimen to thenearest second, and10.1.2.3 If shrinkage of the specimen does not occur duringthe 30s interval.10.1.3 When the specified shrinkage temperature is greaterthan 98C:10.1.3.1 The t
40、emperature at which shrinkage occurs to thenearest 1C, and10.1.3.2 If the temperature of 112C is reached withoutshrinkage.11. Precision and Bias11.1 This test method is adopted from the Federal TestMethod Standard No. 311, Method 7011.1. This method haslong been in use and was approved for publicati
41、on before theinclusion of precision and bias statements was mandated. Theuser is cautioned to verify by the use of reference materials, ifavailable, that the precision and bias (or reproducibility) of thistest method is adequate for the contemplated use.12. Keywords12.1 degree of tannage; leather; s
42、hrinkage; shrinkage tem-perature; tannageASTM 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 th
43、e 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 or withdrawn. Your comments are invited either for revision o
44、f this standard 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 should
45、make 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 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 website(www.astm.org).D 6076 033
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