1、Designation: D8042 18Test Method forShrinkage Temperature of Wet Blue and Wet White1This standard is issued under the fixed designation D8042; 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 p
2、arentheses 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 determination of the shrink-age temperature of all types of Wet Blue and Wet White. Theheating medium is water when th
3、e shrinkage temperature is ator below 98C. The heating medium is a glycerine-watersolution when the shrinkage temperature is above 98C.1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.1.3 This standard does not purport to address
4、 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 regulatory limitations prior to use.1.4 This international standard was develope
5、d 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 Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documen
6、ts2.1 ASTM Standards:2D1517 Terminology Relating to LeatherD6076 Test Method for Shrinkage Temperature of 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 Standard:3.2.1 shrink,
7、vto contract or become smaller.3.2.2 shrinkage, nthe temperature at which noticeableshrinkage occurs when a Wet Blue or Wet White specimen isgradually heated in an aqueous medium.4. Summary of Test Method4.1 A Wet Blue or Wet White specimen is thoroughlysoaked in the aqueous medium that will be used
8、 to heat thespecimen for this test method. This specimen is then fastenedbetween two clamps (one fixed and one movable) and im-mersed in the aqueous medium (see Fig. 1). The aqueousmedium is gradually heated until the specified temperature isreached without shrinkage or until shrinkage is indicated
9、by adeflection of the dial needle which is attached to the movableclamp.5. Significance and Use5.1 This test method is designed to determine the tempera-ture at which the Wet Blue or Wet White specimen experiencesshrinkage. In this test method, shrinkage occurs as a result ofhydrothermal denaturatio
10、n of the collagen protein moleculeswhich make up the fiber structure of the Wet Blue or WetWhite. The shrinkage temperature of Wet Blue or Wet White isinfluenced by many different factors, most of which appear toaffect the number and nature of crosslinking interactionsbetween adjacent polypeptide ch
11、ains of the collagen proteinmolecules. The value of the shrinkage temperature of Wet Blueor Wet White is commonly used as an indicator of the type oftannage or the degree of tannage, or both, of that particular WetBlue or Wet White (especially for the more hydrothermallystable tannages such as chrom
12、e tannage).6. Apparatus6.1 Stand, for supporting the testing equipment.6.2 Indicating Device, either of the two devices listed asfollows:1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition app
13、roved Sept. 1, 2018. Published October 2018. Originallyapproved in 2016. Last previous edition approved in 2016 as D8042-16. DOI:10.1520/D8042-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
14、 volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on
15、standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16.2.1 Theis Shrinkage Meter Diala dial indicator having aface divided into 360 to 38
16、0, with one revolution of the dialhand corresponding to 12.7 mm (0.5 in.) of specimenmovement, and with leeway for four revolutions of the dialhand.36.2.2 AGD (American Gage Design) Dial Indicator, a me-chanical device capable of registering on a scale a reading ofthe shrinkage or swelling movement
17、of the specimen in a ratioof at least 25 units of dial movement (or greater) to 1 unit ofspecimen movement, and shall accurately detect by movementof the dial needle the point at which shrinkage begins. Theindicator shall have a spindle capable of attachment to thespecimen and to the adjustable weig
18、ht assembly.46.3 Immersion Heater, 250 to 500 W, with a heating 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 suf
19、ficiently far apart forgripping the full width of the specimen 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,thermomete
20、r, immersion heater, and the rod fastened to theupper specimen 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, capable of reading from 0 to 100C in1C increments with a
21、tolerance of 60.5C.6.9 Tall-form 1-L 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) contain
22、ing lead shot that shall 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 ad
23、justed accordingly, so that it willnot cause an elongation (prior to shrinkage) of 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
24、 Die, for cutting the specimen to the requireddimensions.6.13 String, (nylon or polyester) for connecting the upperclamp (or the rod connected to the upper clamp) to the weightassembly and passing over the pulley on the indicating dial.7. Reagents7.1 Glycerine-water SolutionWhen glycerine-water me-d
25、ium is specified for 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
26、 over112C.3A shrinkage meter apparatus setup meeting these specific requirements wasformerly available from the Arthur H. Thomas Co., Philadelphia, PA. Usedapparatus of that type may still be available from tanneries or laboratories that havegone out of business or from used equipment dealers. The s
27、ole source of supply ofparts and dials to build a meter meeting the specifications known to the committeeat this time is Schap Specialty Machine, Inc., 17309 Taft Road, Spring Lake, MI49456. If you are aware of alternative suppliers, please provide this information toASTM International Headquarters.
28、 Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.4The sole source of supply of the dial indicator (Model 2282PCC) known to thecommittee at this time is B.C. Ames, Inc., Melrose, MA 02176, .If you are aware of alternative sup
29、pliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.FIG. 1 Shrinkage Meter Apparatus (“Shrinkometer”)D8042 1827.2 De-ionized water may be used for Wet Whit
30、e whichnormally shrinks at less than 98C.8. Test Specimen8.1 The test specimen for the test shall be a rectangle of WetBlue or Wet White 76.0 6 0.5 mm (3.0 in.) in length by 12.56 0.5 mm (0.5 in.) in width, die cut from the sample unit ofWet Blue or Wet White with the long dimension perpendicularto
31、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 Vertically fasten the top and bottom of the specimen inthe two clamps of the shrinkage meter, adjusting the specimento remove any slack. Completely i
32、mmerse the clamped sampleinto the heating solution as described in 7.1 or 7.2. The solutionmay be preheated to 50C (65C). Mark or take note of thelocation of the indicator needle on the dial as the starting point.9.2 Increase the temperature of the heating solution at a rateof 3 to 5C per minute. Sh
33、rinkage is indicated when the dialneedle moves clockwise. Record the shrinkage temperature atthis point. If the needle moves counterclockwise, this is anindication the sample is stretching. Wait until the needle stopsmoving and mark this location on the dial as the new startingpoint. Monitor the dia
34、l for clockwise movement and record theshrinkage temperature.10. Report10.1 Report the following information:10.1.1 Heating solution used: glycerine/water medium, orwater.10.1.2 The temperature at which shrinkage occurs to thenearest 1C.10.1.3 If the temperature of 110C is reached withoutshrinkage.1
35、1. Precision and Bias11.1 This test method is adopted from Test Method D6076.The user is cautioned to verify by the use of referencematerials, if available, that the precision and bias (or reproduc-ibility) of this test method is adequate for the contemplated use.12. Keywords12.1 boil test; degree o
36、f tannage; shrinkage; shrinkagetemperature; tannage; Wet Blue; Wet WhiteASTM 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
37、 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 or withdrawn. Your comments ar
38、e invited either for revision of 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 rec
39、eived 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 reprints (single or multiple copies)
40、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:/ 183
