1、Designation: D6076 18Standard Test Method forShrinkage Temperature of Leather1This standard is issued under the fixed designation D6076; 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 parenth
2、eses 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 This test method covers the determination of the shrink-age temper
3、ature 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 parenthes
4、es 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, health, and environmental practices and deter-mine the applicability of regulato
5、ry limitations prior to use.1.4 This international standard was developed in accor-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 Organ
6、ization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1517 Terminology Relating to Leather3. Terminology3.1 DefinitionsFor definitions of general leather termsused in this test method, refer to Terminology D1517.3.2 Definitions of Terms Specific to This Stand
7、ard:3.2.1 shrinkto contract or become smaller.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 spe
8、cimen for this testmethod. This specimen is then fastened between two clamps(one fixed and one movable) and immersed in the aqueousmedium (see Fig. 1). The aqueous medium is gradually heateduntil the specified temperature is reached without shrinkage oruntil shrinkage is indicated by a deflection of
9、 the dial needlewhich is attached to the movable clamp.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 collag
10、en protein moleculeswhich make up the fiber structure 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
11、 value of the shrinkagetemperature of leather is commonly 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
12、.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 C
13、enter, Directorateof Clothing and Textiles, Philadelphia, PA and the U.S. Army Natick Research,Development and Engineering Center, Natick, MA.Current edition approved Sept. 1, 2018. Published October 2018. Originallyapproved in 1997. Last previous edition approved in 2013 as D6076-08 (2013).DOI: 10.
14、1520/D6076-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor D
15、rive, PO Box C700, West 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
16、issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16.2 Indicating Device, either of the two devices listed 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
17、.5 in.) of specimenmovement, and with leeway for four revolutions of the dialhand.36.2.2 AGD (American Gage Design) Dial IndicatorAmechanical 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 gr
18、eater) to 1 unitof specimen movement, and shall accurately detect by move-ment of the dial needle the point at which shrinkage begins.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 heating elem
19、entnot 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 at the
20、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 clamp.6
21、.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 Tall-form
22、 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 beattach
23、ed 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 that it wi
24、llnot 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 specimen to
25、 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 for use
26、(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.3A shrinkage meter apparatus setup meeting these specific requirements wasformerly available from the Arthur H. Thomas Co., Philadelphia, PA. T
27、he 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 from used equipmentdealers.4The sole source of supply of the dial ind
28、icator (Model 2282PCC) known to thecommittee at this time is B.C. Ames, Inc., Melrose, MA 02176, .If you are aware of alternative suppliers, please provide this information to ASTMHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which
29、 you may attend.FIG. 1 Shrinkage Meter Apparatus (“Shrinkometer”)D6076 182The specific gravity of the solution shall be adjusted to 1.19 at23C. The glycerine-water solution shall not be heated over112C.8. Test Specimen8.1 The test specimen for the test shall be a rectangle ofleather 76.0 6 0.5 mm (3
30、.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 specification,one test specimen shall be tested from each sample unit.9. Procedure9.1 When shrinkage
31、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 Prepare the specimens as follows prior to mounting inthe holding clamps. Place more than 15
32、 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 intermittent vacuum until all the specimens settleto the bottom of the flask. Gently shake
33、 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 and mount in the shrinkage meter. Keep the otherspecimens in the flask (containing the he
34、ating 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 of the shrinkagemeter and completely immerse in the heating medium, whichhas been preheate
35、d 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 increased at a rateof 3 to 5C/min, the reference point at which the indicatorcomes to rest shall b
36、e 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 shrinks oruntil the specified shrinkage temperature is reached.9.6 When the material spec
37、ification 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 98C.Keep the temperature at 98 6 0.5C for 30 s by adjusting thetransformer. If the specimen
38、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 temperature at which shrinkage occurs.9.7 When a shrinkage temperature of over 98C is spec
39、ified,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 information:10.1.1 When the specified shrinkage temperature is 98C orless:10.1.1.1 If the s
40、pecimen shrinks before the temperaturereaches 98C, report the temperature at which shrinkage occursto the nearest 1C, and10.1.1.2 If the specified temperature 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
41、 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 interval,report the number of seconds that elapsed between reaching thetemperature of 98C and shrinkage of the specimen to thenearest second, and10.1.
42、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 temperature at which shrinkage occurs to thenearest 1C, and10.1.3.2 If the temperature of 112C is reached withoutshrinkage.11. Precision and Bias11.1
43、 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 publication before theinclusion of precision and bias statements was mandated. Theuser is cautioned to verify by the use of reference materials, ifavailable,
44、 that the precision and bias (or reproducibility) of thistest method is adequate for the contemplated use.12. Keywords12.1 degree of tannage; leather; shrinkage; shrinkage tem-perature; tannageD6076 183ASTM International takes no position respecting the validity of any patent rights asserted in conn
45、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
46、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
47、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
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