1、Designation: D8042 16Test 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1517 Terminology
5、 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, vto contract or become smaller.3.2.2 sh
6、rinkage, 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 to heat thespecimen for this test meth
7、od. This specimen is then fastenedbetween two clamps (one fixed and one movable) and im-mersed in the aqueous medium. The aqueous medium isgradually heated until the specified temperature is reachedwithout shrinkage or until shrinkage is indicated by a deflectionof the dial needle which is attached
8、to the movable clamp.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 denaturation of the collagen protein moleculeswhich make up th
9、e 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 chains of the collagen proteinmolecules. The value of
10、 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 chrome tannage).6. Apparatus6.1 Stand, for supporting th
11、e testing equipment.6.2 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 (0.5 in.) of specimenmovement, and with leeway for four revolution
12、s 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 of the specimen in a ratioof at least 25 units of dial movement (or greater) to 1 unit ofspecimen movement, and shall accurately d
13、etect by movementof the dial needle the point at which shrinkage begins. The1This 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 approved June 1, 2016. Published June 2016. DOI: 10.1520/D8042-1
14、6.2For 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.3A shrinkage meter apparatus setup meeting these specific r
15、equirements 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 sole source of supply ofparts and dials to build a meter meeting the s
16、pecifications 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. Your comments will receive careful consider-ation at a meeting of th
17、e responsible technical committee,1which you may attend.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1indicator shall have a spindle capable of attachment to thespecimen and to the adjustable weight assembly.46.3 Immersion Heater, 2
18、50 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 sufficiently far apart forgripping the
19、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,thermometer, immersion heater, and the rod fas
20、tened 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 tolerance of 60.5C.6.9 Tall-form 1-L
21、 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 beattached
22、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 willn
23、ot 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 Die, for cutting the specimen to th
24、e 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-dium is specified for use (that is, w
25、hen 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.7.2 De-ionized water may b
26、e used for Wet White 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 dimensi
27、on perpendicularto 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
28、slack. Completely immerse 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 t
29、o 5C per minute. Shrinkage 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 startingpoi
30、nt. Monitor the dial 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
31、 withoutshrinkage.11. 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
32、boil test; degree of tannage; shrinkage; shrinkagetemperature; tannage; Wet Blue; Wet White4The 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 suppliers, please provide this inform
33、ation to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.D8042 162ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned
34、in 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 responsible technical committee and m
35、ust 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 consideration at a meeting of t
36、heresponsible 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, 100 Barr Harbor Drive, PO Box C7
37、00, 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). 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:/ 163
