ASTM D8042-16

Test Method for Shrinkage Temperature of Wet Blue and Wet White

SIGNIFICANCE AND USE
5.1 This test method is designed to determine the temperature at which the Wet Blue or Wet White specimen experiences shrinkage. In this test method, shrinkage occurs as a result of hydrothermal denaturation of the collagen protein molecules which make up the fiber structure of the Wet Blue or Wet White. The shrinkage temperature of Wet Blue or Wet White is influenced by many different factors, most of which appear to affect the number and nature of crosslinking interactions between adjacent polypeptide chains of the collagen protein molecules. The value of the shrinkage temperature of Wet Blue or Wet White is commonly used as an indicator of the type of tannage or the degree of tannage, or both, of that particular Wet Blue or Wet White (especially for the more hydrothermally stable tannages such as chrome tannage).
SCOPE
1.1 This test method covers the determination of the shrinkage temperature of all types of Wet Blue and Wet White. The heating medium is water when the shrinkage temperature is at or below 98°C. The heating medium is a glycerine-water solution when the shrinkage temperature is above 98°C.  
1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-May-2016
• ICS: 59.140.30 - Leather and furs
• Technical Committee: D31 - Leather
• Drafting Committee: D31.02 - Wet Blue

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D8042 − 16
Test Method for
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Shrinkage Temperature of Wet Blue and Wet White
This standard is issued under the fixed designation D8042; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope gradually heated until the specified temperature is reached
withoutshrinkageoruntilshrinkageisindicatedbyadeflection
1.1 This test method covers the determination of the shrink-
of the dial needle which is attached to the movable clamp.
age temperature of all types of Wet Blue and Wet White. The
heating medium is water when the shrinkage temperature is at
5. Significance and Use
or below 98°C. The heating medium is a glycerine-water
5.1 This test method is designed to determine the tempera-
solution when the shrinkage temperature is above 98°C.
ture at which the Wet Blue or Wet White specimen experiences
1.2 The values stated in SI units are to be regarded as the
shrinkage. In this test method, shrinkage occurs as a result of
standard. The values in parentheses are for information only.
hydrothermal denaturation of the collagen protein molecules
1.3 This standard does not purport to address all of the
which make up the fiber structure of the Wet Blue or Wet
safety concerns, if any, associated with its use. It is the
White. The shrinkage temperature of Wet Blue or Wet White is
responsibility of the user of this standard to establish appro-
influenced by many different factors, most of which appear to
priate safety and health practices and determine the applica-
affect the number and nature of crosslinking interactions
bility of regulatory limitations prior to use.
between adjacent polypeptide chains of the collagen protein
molecules.The value of the shrinkage temperature ofWet Blue
2. Referenced Documents
or Wet White is commonly used as an indicator of the type of
2
tannage or the degree of tannage, or both, of that particularWet
2.1 ASTM Standards:
Blue or Wet White (especially for the more hydrothermally
D1517 Terminology Relating to Leather
stable tannages such as chrome tannage).
D6076 Test Method for Shrinkage Temperature of Leather
6. Apparatus
3. Terminology
6.1 Stand, for supporting the testing equipment.
3.1 Definitions—For definitions of general leather terms
used in this test method, refer to Terminology D1517.
6.2 Indicating Device, either of the two devices listed as
follows:
3.2 Definitions of Terms Specific to This Standard:
6.2.1 Theis Shrinkage Meter Dial—a dial indicator having a
3.2.1 shrink, v—to contract or become smaller.
face divided into 360 to 380°, with one revolution of the dial
3.2.2 shrinkage, n—the temperature at which noticeable
hand corresponding to 12.7 mm (0.5 in.) of specimen
shrinkage occurs when a Wet Blue or Wet White specimen is
movement, and with leeway for four revolutions of the dial
gradually heated in an aqueous medium.
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hand.
6.2.2 AGD (American Gage Design) Dial Indicator, a me-
4. Summary of Test Method
chanical device capable of registering on a scale a reading of
4.1 A Wet Blue or Wet White specimen is thoroughly
the shrinkage or swelling movement of the specimen in a ratio
soaked in the aqueous medium that will be used to heat the
of at least 25 units of dial movement (or greater) to 1 unit of
specimen for this test method. This specimen is then fastened
specimen movement, and shall accurately detect by movement
between two clamps (one fixed and one movable) and im-
of the dial needle the point at which shrinkage begins. The
mersed in the aqueous medium. The aqueous medium is
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A shrinkage meter apparatus setup meeting these specific requirements was
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This test method is under the jurisdiction ofASTM Committee D31 on Leather formerly available from the Arthur H. Thomas Co., Philadelphia, PA. Used
and is the direct responsibility of Subcommittee D31.02 on Wet Blue. apparatus of that type may still be available from tanneries or laboratories that have
Current edition approved June 1, 2016. Published June 2016. DOI: 10.1520/ gone out of business or from used equipment dealers. The sole source of supply of
D8042-16. parts and dials to build a meter meeting the specifications known to the committee
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or at this time is Schap Specialty Machine, Inc., 17309 Taft Road, Spring Lake, MI
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM 49456. If you are aware of alternative suppliers, please provide this information to
Standards volume information, refer to the standard’s Document Summary page on ASTM International Headquarters. Your comments will receive careful consider-
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