ASTM D8042-18(2023)
(Test Method)Test Method for Shrinkage Temperature of Wet Blue and Wet White
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
- Status
- Published
- Publication Date
- 31-Aug-2023
- Technical Committee
- D31 - Leather
- Drafting Committee
- D31.02 - Wet Blue
Relations
- Effective Date
- 01-Dec-2015
- Effective Date
- 01-May-2013
- Effective Date
- 01-Oct-2010
- Effective Date
- 01-Sep-2008
- Effective Date
- 01-Oct-2006
- Effective Date
- 01-Sep-2004
- Effective Date
- 01-Sep-2004
- Effective Date
- 01-Apr-2004
- Effective Date
- 01-Oct-2003
- Effective Date
- 10-May-1999
- Effective Date
- 10-Feb-1997
Overview
ASTM D8042-18(2023) specifies a standardized test method for determining the shrinkage temperature of Wet Blue and Wet White leather substrates. The shrinkage temperature is a critical parameter, indicating the temperature at which hydrothermal denaturation of collagen occurs, leading to visible shrinkage of the specimen. This test method is widely recognized in the leather industry and by quality control laboratories for characterizing the type and degree of tannage in processed hides and skins. The protocol uses water as the heating medium for temperatures up to 98 °C and a glycerine-water solution for higher temperatures, ensuring accurate and repeatable measurements for all types of Wet Blue and Wet White.
Key Topics
- Shrinkage Temperature: The temperature at which Wet Blue or Wet White leather undergoes noticeable contraction due to protein denaturation.
- Wet Blue and Wet White: Semi-processed leather substrates, typically tanned using chrome (Wet Blue) or alternative (Wet White) processes.
- Hydrothermal Denaturation: The structural instability of collagen at high temperatures, leading to shrinkage.
- Tannage Assessment: Shrinkage temperature serves as an indicator for the type, degree, and effectiveness of the leather tannage process.
- Test Method Conditions:
- Water is used as the heating medium at or below 98 °C.
- A glycerine-water solution is applied above 98 °C.
- Apparatus and Measurement: Precise equipment setup and temperature control are essential for reliable results.
Applications
The ASTM D8042-18(2023) test method plays a vital role in several practical areas of the leather processing and quality control industry:
- Quality Control: Used to verify that Wet Blue and Wet White meet specific shrinkage temperature requirements correlated with proper tannage and hydrothermal stability.
- Process Optimization: Facilitates the comparison of different tannage methods (e.g., chrome versus alternative processes) based on the resistance to thermal shrinkage.
- Material Selection: Assists manufacturers and product engineers in selecting suitable leather substrates for end-use applications demanding certain thermal properties.
- Compliance and Certification: Supports conformity with international leather standards, ensuring products meet industry and market requirements.
- Research and Development: Enables leather technologists and chemists to study the effects of various crosslinking interactions and chemical treatments on shrinkage performance.
- Inspection and Validation: Provides an objective metric for third-party verification in procurement, dispute resolution, and supply chain management.
Related Standards
Organizations often reference and align ASTM D8042-18(2023) with other ASTM standards and leather industry guidelines:
- ASTM D1517: Terminology Relating to Leather - Essential for understanding terms used throughout the test method.
- ASTM D6076: Test Method for Shrinkage Temperature of Leather - An established protocol for similar shrinkage assessments.
- ISO and EN Leather Standards: Various international standards address physical testing in leather, contributing to harmonized quality documentation.
- World Trade Organization (WTO) TBT Principles: This ASTM standard complies with internationally recognized principles for standardization, providing global acceptance.
By following ASTM D8042-18(2023), users gain consistent, reliable results for shrinkage temperature, enabling informed decisions across manufacture, procurement, and research in the leather industry. This standard forms a critical part of the quality assurance toolkit for all stakeholders in Wet Blue and Wet White processing and use.
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Frequently Asked Questions
ASTM D8042-18(2023) is a standard published by ASTM International. Its full title is "Test Method for Shrinkage Temperature of Wet Blue and Wet White". This standard covers: 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
ASTM D8042-18(2023) is classified under the following ICS (International Classification for Standards) categories: 59.140.30 - Leather and furs. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM D8042-18(2023) has the following relationships with other standards: It is inter standard links to ASTM D1517-15, ASTM D6076-08(2013), ASTM D1517-10, ASTM D6076-08, ASTM D1517-06, ASTM D1517-04, ASTM D1517-04e1, ASTM D1517-99(2004), ASTM D6076-03, ASTM D1517-99, ASTM D6076-97. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ASTM D8042-18(2023) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D8042 − 18 (Reapproved 2023)
Test Method for
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 3.2 Definitions of Terms Specific to This Standard:
3.2.1 shrink, v—to contract or become smaller.
1.1 This test method covers the determination of the shrink-
3.2.2 shrinkage, n—the temperature at which noticeable
age temperature of all types of Wet Blue and Wet White. The
shrinkage occurs when a Wet Blue or Wet White specimen is
heating medium is water when the shrinkage temperature is at
gradually heated in an aqueous medium.
or below 98 °C. The heating medium is a glycerine-water
solution when the shrinkage temperature is above 98 °C.
4. Summary of Test Method
1.2 The values stated in SI units are to be regarded as the
4.1 A Wet Blue or Wet White specimen is thoroughly
standard. The values in parentheses are for information only.
soaked in the aqueous medium that will be used to heat the
1.3 This standard does not purport to address all of the
specimen for this test method. This specimen is then fastened
safety concerns, if any, associated with its use. It is the
between two clamps (one fixed and one movable) and im-
responsibility of the user of this standard to establish appro-
mersed in the aqueous medium (see Fig. 1). The aqueous
priate safety, health, and environmental practices and deter-
medium is gradually heated until the specified temperature is
mine the applicability of regulatory limitations prior to use.
reached without shrinkage or until shrinkage is indicated by a
1.4 This international standard was developed in accor-
deflection of the dial needle which is attached to the movable
dance with internationally recognized principles on standard-
clamp.
ization established in the Decision on Principles for the
5. Significance and Use
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
5.1 This test method is designed to determine the tempera-
Barriers to Trade (TBT) Committee.
ture at which the Wet Blue or Wet White specimen experiences
shrinkage. In this test method, shrinkage occurs as a result of
2. Referenced Documents
hydrothermal denaturation of the collagen protein molecules
2.1 ASTM Standards:
which make up the fiber structure of the Wet Blue or Wet
D1517 Terminology Relating to Leather
White. The shrinkage temperature of Wet Blue or Wet White is
D6076 Test Method for Shrinkage Temperature of Leather
influenced by many different factors, most of which appear to
affect the number and nature of crosslinking interactions
3. Terminology
between adjacent polypeptide chains of the collagen protein
3.1 Definitions—For definitions of general leather terms
molecules. The value of the shrinkage temperature of Wet Blue
used in this test method, refer to Terminology D1517.
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
This test method is under the jurisdiction of ASTM Committee D31 on Leather Blue or Wet White (especially for the more hydrothermally
and is the direct responsibility of Subcommittee D31.02 on Wet Blue.
stable tannages such as chrome tannage).
Current edition approved Sept. 1, 2023. Published September 2023. Originally
approved in 2016. Last previous edition approved in 2018 as D8042 – 18. DOI:
6. Apparatus
10.1520/D8042-18R23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6.1 Stand, for supporting the testing equipment.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.2 Indicating Device, either of the two devices listed as
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. follows:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8042 − 18 (2023)
indicator shall have a spindle capable of attachment to the
specimen and to the adjustable weight assembly.
6.3 Immersion Heater, 250 W to 500 W, with a heating
element not longer than 140 mm (5 ⁄2 in.) and a depth of
immersion not in excess of 152 mm (6 in.).
6.4 Variable Speed Stirrer, with small blades.
6.5 Spring-loaded Clamps, (alligator type), two, mounted
vertically one above the other and sufficiently far apart for
gripping the full width of the specimen at the ends. The bottom
clamp shall be fastened to the end of a U-shaped rod that can
be turned sideways. The upper clamp shall be movable
sideways as well as up and down.
6.6 Metal Supporting Plate, with apertures for the stirrer,
thermometer, immersion heater, and the rod fastened to the
upper specimen clamp.
6.7 Variable Transformer, capable of controlling the rate of
heating (3 °C ⁄min to 5 °C ⁄min) of the aqueous medium and
capable of maintaining a temperature of 98 °C 6 0.5 °C.
6.8 Thermometer, capable of reading from 0 °C to 100 °C in
1 °C increments with a tolerance of 60.5 °C.
6.9 Tall-form 1 L Beaker, for holding the aqueous heating
medium.
6.10 Lead Shot.
6.11 Indicating Device, attached to the upper (movable)
clamp and equipped with an adjustable weight assembly
mounted over a pulley. The weight assembly shall consist of a
small bottle (with a lid) containing lead shot that shall be
attached to the string running over the pulley. The weight
assembly shall be approximately 178 g to counterbalance the
weight of the clamp, to overcome any inertia or friction of the
indicating device, and to maintain the specimen under a slight
tension. The weight shall be adjusted accordingly, so that it will
not
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