ASTM D6401-99(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: D6401 − 99 (Reapproved 2020)
Standard Test Method for
Determining Non-Tannins and Tannin in Extracts of
Vegetable Tanning Materials
This standard is issued under the fixed designation D6401; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D4903Test Method for Total Solids and Water in Vegetable
Tanning Material Extracts
1.1 This test method is intended for use in determining the
D4905Practice for Preparation of Solution of Solid, Pasty
quantity of soluble non-tannins and tannin in solutions of
and Powdered Vegetable Tannin Extracts
tannin extracts, water extracts of vegetable tanning materials,
D6402Test Method for Determining Soluble Solids and
or tanning liquors. The method is applicable to the analysis of
Insolubles in Extracts of Vegetable Tanning Materials
liquid, solid, pasty, and powdered extracts and to extracts of
D6405Practice for Extraction of Tannins from Raw and
raw or spent materials.
Spent Materials
1.2 The values stated in SI units are to be regarded as the
2.2 ALCA Method:
standard. The values given in parentheses after SI units are for 3
A22Non-Tannins and Tannin
information only and are not considered standard.
3. Terminology
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 Definitions:
responsibility of the user of this standard to establish appro-
3.1.1 soluble non-tannins—non-volatile materials present in
priate safety, health, and environmental practices and deter-
tannin extracts and raw or spent materials that are dissolved or
mine the applicability of regulatory limitations prior to use.
suspendedinwater,arepartofthesolublesolidsdeterminedby
1.4 This international standard was developed in accor-
Test Method D6402, and do not react with or bind to hide
dance with internationally recognized principles on standard-
powder when mixed as in this test method.
ization established in the Decision on Principles for the
3.1.2 tannins—non-volatile materials present in tannin ex-
Development of International Standards, Guides and Recom-
tracts and raw or spent materials that are dissolved or sus-
mendations issued by the World Trade Organization Technical
pended in water, are part of the soluble solids determined by
Barriers to Trade (TBT) Committee.
Test Method D6402, and do react with or bind to hide powder
when mixed as in this test method.
2. Referenced Documents
2.1 ASTM Standards:
4. Summary of Test Method
D2617Test Method for Total Ash in Leather
4.1 An aliquot of the analytical solution prepared from
D3790 Test Method for Volatile Matter (Moisture) of
tannin extracts (Practices D4901 or D4905) or of the water
Leather by Oven Drying
extract from raw or spent materials (Practice D6405) is dried
D4901Practice for Preparation of Solution of Liquid Veg-
overnight in a forced-air oven (Test Method D4902) and the
etable Tannin Extracts
solid residue remaining is determined and defined as the total
D4902Test Method for Evaporation and Drying ofAnalyti-
solidsforthatsample(TestMethodD4903).Anotheraliquotof
cal Solutions
the same solution is passed through a specified filtering
procedure and the quantity of solid residue remaining in the
filtrate is determined and defined as the soluble solids for that
ThistestmethodisunderthejurisdictionofASTMCommitteeD31onLeather
sample; the calculated difference between the total solids and
and is the direct responsibility of Subcommittee D31.01 on Vegetable Leather.This
methodhasbeenadaptedfrom,andisareplacementfor,MethodA22oftheOfficial the soluble solids is defined as the insolubles for that sample
Methods of the American Leather Chemists Association.
(Test Method D6402). Another aliquot of the original analyti-
Current edition approved Dec. 1, 2020. Published December 2020. Originally
cal solution or water extract is mixed with a prepared hide
approved in 1999. Last previous edition approved in 2016 as D6401–99(2016).
DOI: 10.1520/D6401-99R20.
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 Official Methods of the American Leather Chemists Association. Available
Standards volume information, refer to the standard’s Document Summary page on from the American Leather Chemists Association, University of Cincinnati, P.O.
the ASTM website. Box 210014, Cincinnati, OH 45221-0014.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6401 − 99 (2020)
powder material, with the resulting solution being passed 6.5 Filter Paper , 21.5 cm diameter, pleated to contain 32
through the same filtering procedure as for the soluble solids evenly divided creases.
analysis. The quantity of solid residue remaining in the filtrate
6.6 Funnel, 100 to 125 mm top diameter, 60° angle bowl,
is determined and defined as the soluble non-tannins for that
and 150 mm stem length.
sample; the calculated difference between the total soluble
6.7 Shake Bottles, 0.95 L(32 oz), with rubber stoppers.The
solids and the soluble non-tannins is defined as the tannin
bottles shall be approximately 21.6 cm (8.5 in.) overall height
content for that sample.
and 8.9 cm (3.5 in.) diameter. One-quart canning jars (Mason-
type) with plastic screw-on lids work well.
5. Significance and Use
6.8 Shaking Machine,rotatingtype,equippedtohold0.95L
5.1 This test method is used to determine the proportion of
(32 oz) bottles for end-over-end agitation of hide powder and
the total soluble solids which are soluble non-tannins and the
analytical solution. The speed of rotation shall be 60 6 2 rpm,
proportion which are tannins in a solution of tannin extract or
and the machine shall be so constructed that the side of the
in the water extract from raw or spent materials prepared for
shake bottle adjacent to the rotating shaft shall be not less than
tannin analysis. 5.1 cm (2 in.) nor more than 7.6 cm (3 in.) from the center of
the shaft.
5.2 Thespecimensarealiquotsfromtheanalyticalsolutions
6.9 Cloth, The cloth shall be of cotton, with a nominal
prepared from tannin extracts or the water extract solutions
(unbleached) thread count of 48 by 48 and a weight of 1.65
prepared from raw or spent materials.
yardsper454g(1lb).Whenbleached,thethreadcountwillbe
5.3 Thesolublenon-tanninsaredefinedastheportionofthe
approximately 52 to 53 by 43 to 48.
soluble solids which are not absorbed or bound by a prepared
6.10 Kaolin , acid-washed kaolin clay which conforms to
hide powder material.
the following specifications:
5.4 The tannins are defined as the portion of the soluble 6.10.1 Suspend 1.0 g kaolin in 100 mL distilled water. The
solids which are absorbed or bound by a prepared hide powder pH value should be between 4.5 and 6.0 after 5 min.
6.10.2 Amixture of 2.0 g kaolin and 200 mLdistilled water
material.
are shaken for 10 min and the mixture filtered through the
5.5 The results of this test method are dependent on a great
standard filter paper (see 6.5). A100 mL aliquot of the clear
many variables, but particularly upon:
filtrate should have less than 0.001 g of residue after evapora-
5.5.1 The temperature conditions under which the solutions
tion and oven-drying in a platinum dish.
were prepared and stored and the temperature at which the
6.11 Chrome Alum Solution, a 3% solution, prepared by
current analysis is performed;
dissolving CrK(SO ) 12 H O in distilled water at room
4 2 2
5.5.2 The uniformity and consistency of the Kaolin paste
temperature (3 g per 100 mL of solution). The solution shall
layer deposited onto the filter paper;
not be more than 30 days old when used.
5.5.3 The rate of solution run-out from the pipette; 5
6.12 Hide Powder —The hide powder shall meet the fol-
5.5.4 Conditionsrelatedtothepropertiesofthehidepowder
lowing specifications:
used to react with the tannin content of the solution; etc. It is,
6.12.1 The hide powder shall be finely ground and uniform
therefore, essential that the method be followed exactly in
in texture with no lumps present.
order to obtain reproducible results both among specimens
6.12.2 The moisture content should be 12 to 15% as
within a laboratory and for analyses between laboratories.
determined by Test Method D4902.
6.12.3 The ash content shall be less than 0.3% as deter-
6. Apparatus and Reagents
mined by Test Method D2617.
6.12.4 Amixturepreparedfrom7.0gofair-dryhidepowder
6.1 Tannin Dish, crystallizing dish, borosilicate glass, 50
suspended in 100 mLof 0.1 N KCl and set aside for 24 h with
mm tall, 70 mm outside diameter. The bottom corner shall be
occasional shaking shall have a pH value not less than 5.0 nor
rounded to a radius of 6 mm, the bottom shall be flat and not
greater than 5.4.
cupped in the center, and the top edge shall be rounded and
6.12.5 Asampleofthehidepowdershallbecarriedthrough
polished.
the analytical procedure for the determination of non-tannins
6.2 Watch Glass, a suitable size (approximately 150 mm
diameter) to be used as a cover for the funnel and filter paper
andasuitablesize(75mm)tobeusedasacoverforthetannin
The sole source of supply of S&S No. 610 filter paper known to the committee
at this time is Schleicher & Schuell, 10 OpticalAvenue, P.O. Box 2012, Keene, NH
dishes.
03431. If you are aware of alternative suppliers, please provide this information to
ASTMHeadquarters.Yourcommentswillreceivecarefulconsiderationatameeting
6.3 Pipet, 100 mL capacity, preferably with a wide orifice
of the responsible technical committee, which you may attend.
approximately 2.4 mm ( ⁄32 in.) diameter and 15-25 s delivery
The sole source of supply of Kaolin and hide powder known to the committee
time.
atthistimeisL.H.Lincoln&Son,Inc.,203CherryStreet,Coudersport,PA16915.
If you are aware of alternative suppliers, please provide this information toASTM
6.4 Volumetric Flasks, graduated to deliver 200 mL boro-
Headquarters.Your comments will receive careful consideration at a meeting of the
silicate flask (Pyrex No. 5840 works well). responsible technical committee, which you may attend.
D6401 − 99 (2020)
described below using distilled water in place of the analytical with four successive portions of distilled water at 23 to 25 °C,
solution.Thewater-solublecontento
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