ASTM D6409-99(2020)

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: D6409 − 99 (Reapproved 2020)
Standard Practice for
Color Tests with Sheepskin Skiver
This standard is issued under the fixed designation D6409; 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. Terminology
1.1 This practice covers making color tests of all types of 3.1 Definitions:
vegetable tanning extracts and of vegetable tanning materials 3.1.1 For definitions of general leather and tanning terms
to determine the color imparted to tanned skins. used in this practice refer to Terminology D1517.
3.1.2 pickled skiver—a sheepskin skiver that has been pick-
1.2 The values stated in SI units are to be regarded as
led in a solution of salt and sulfuric acid.
standard. The values given in parentheses after SI units are
3.1.3 sheepskin skiver—the grain split of a de-wooled
provided for information only and are not considered standard.
sheepskin. A pickled skiver is used for this test.
1.3 This standard does not purport to address all of the
3.1.4 tannin—an astringent substance found in the various
safety concerns, if any, associated with its use. It is the
parts of plants such as bark, wood, leaves, nuts, fruits, roots,
responsibility of the user of this standard to establish appro-
etc.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3.1.5 vegetable tannins—mixtures of substances (natural
1.4 This international standard was developed in accor-
products) obtained from plant tissues by water extraction
dance with internationally recognized principles on standard-
which have the chemical and physical properties necessary to
ization established in the Decision on Principles for the
convert animal hides and skins into leather.
Development of International Standards, Guides and Recom-
4. Summary of Practice
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.1 Aspecimen of pickled skiver is tanned with a sample of
vegetable tanning liquor in order to determine the color which
2. Referenced Documents
will be imparted to a clear, clean hide or skin that is tanned
2.1 ASTM Standards: with this tanning liquor.
D1517 Terminology Relating to Leather
5. Significance and Use
D4901 Practice for Preparation of Solution of Liquid Veg-
etable Tannin Extracts
5.1 This practice provides a standard procedure for compar-
D4905 Practice for Preparation of Solution of Solid, Pasty ingthecolorofleathertannedwithdifferenttanningextractsor
and Powdered Vegetable Tannin Extracts
mixtures of extracts or for monitoring the color consistency of
D6405 Practice for Extraction of Tannins from Raw and tannery liquors.
Spent Materials
6. Apparatus and Reagents
2.2 ALCA Methods:
6.1 Pickled Sheepskin Skiver, specially and consistently
A40 Color Tests with Sheepskin Skiver
selected for the color test.
6.2 Borax, commercial grade such as may be used in a
This practice is under the jurisdiction ofASTM Committee D31 on Leather and
tannery.
is the direct responsibility of Subcommittee D31.01 on Vegetable Leather. This test
method has been adapted from and is a replacement for MethodA40 of the Official
6.3 Containers, 10 and 3 L capacity and made of suitable
Methods of the American Leather Chemists Association.
material to be resistant to the chemicals and materials used in
Current edition approved Dec. 1, 2020. Published December 2020. Originally
the tanning procedure employed by this practice.
approved in 1999. Last previous edition approved in 2014 as D6409 – 99 (2014).
DOI: 10.1520/D6409-99R20.
6.4 Acetic Acid, glacial, commercial grade.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.5 Sodium Acetate, crystal, commercial grade.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 6.6 Sodium Chloride, crystal, commercial grade.
Official Methods of the American Leather Chemists Association. Available
6.7 Shake Bottles, 0.95 L(32 oz), with rubber stoppers. The
from the American Leather Chemists Association, University of Cincinnati, P.O.
Box 210014, Cincinnati, OH 45221-0014. bottles shall be approximately 21.6 cm (8.5 in.) overall height
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6409 − 99 (2020)
and 8.9 cm (3.5 in.) diameter. One quart canning jars (Mason- 9. Procedure for Making Color Tests
type) with plastic screw-on lids work well.
9.1 Remove the salt from the skiver sample 10 by 15 cm (4
6.8 Shaking Machine,rotatingtype,equippedtohold0.95L
by6in.)byshakingwithfourchangesofdistilledwater,of500
(32 oz) bottles for end-over-end agitation of hide powder and
mL each and at 23 to 25 °C, in a s
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