ASTM D3790-79(1996)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: D 3790 – 79 (Reapproved 1996)
Standard Test Method for
Volatile Matter (Moisture) of Leather by Oven Drying
This standard is issued under the fixed designation D 3790; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4.5 Because of the above unknown errors, the result of this
test is a purely arbitrary value for the moisture content of the
1.1 This test method covers the determination of volatile
sample. It is, therefore, essential that the method be followed
matter (moisture) in all types of leather.
exactly in order to obtain reproducible results among labora-
1.2 This standard does not purport to address all of the
tories. This is particularly true if other chemical analytical tests
safety concerns, if any, associated with its use. It is the
being performed on the same sample are reported on the
responsibility of the user of this standard to establish appro-
moisture-free basis.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
5. Apparatus
2. Referenced Documents 5.1 Weighing Bottle , glass, low-form, cylindrical with a
ground-glass stopper of standard taper. The bottle shall have 70
2.1 ASTM Standards:
6 5 mm inside diameter, and 33 6 3 mm overall height.
D 2813 Practice for Sampling Leather for Physical and
2 5.2 Oven, mechanical-convection draft capable of setting at
Chemical Tests
100°C, with a thermoregulator system capable of holding oven
E 180 Practice for Determining the Precision of ASTM
3 temperature within 6 2°C of set point. A thermometer accurate
Methods for Analysis and Testing of Industrial Chemicals
to 60.2°C should be used to check and monitor the oven set
3. Summary of Test Method point.
5.3 Balance, capable of weighing up to 100 g with an
3.1 The ground leather specimen is heated in a mechanical-
accuracy of 60.001 g.
convection oven for 16 h at 100°C, placed in a desiccator,
5.4 Desiccator, any convenient form or size, using any
cooled, and reweighed. The loss in weight represents the
normal desiccating agent such as calcium sulfate, calcium
volatile matter.
chloride, or silica gel.
4. Significance and Use
6. Sampling
4.1 The result obtained by this test is normally considered to
6.1 The leather shall be sampled in accordance with Practice
be the moisture content of the leather sample. This result is
D 2813.
used to correct all other chemical tests to a moisture-free basis.
4.2 Materials that are volatile under these conditions, other
7. Procedure
than water, may be present in the leather, although their amount
7.1 Insert the empty weighing bottle inside the inverted
in any normal leather would be expected to be a very small
stoppered cap and place on a shelf in the oven at 100 6 2°C for
percentage of the total volatile matter.
1 h or more. If the stopper has a handle then the stopper may
4.3 Under the conditions of this test, certain materials in
be placed on the shelf in the oven near the empty weighing
leather, such as protein fiber and chromium tanning salts, may
bottle.
retain moisture. Other materials, such as tannins and oils, may
7.2 Remove and place in a desiccator for at least 2 h to cool.
be oxidized. Both of these effects produce negative errors in
7.3 Weigh and record to the nearest 60.001 g.
the moisture determination.
7.4 Use the ground leather sample as specified in Practice
4.4 The amount of volatile matter (moisture) released by a
D 2813 and transfer 5 6 1 g of ground leather into the
given leather varies with (a) degree of grinding of the sample,
previously weighed weighing bottle and stopper the bottle.
(b) weight of sample taken, (c) temperature and time of the
7.5 Weigh the stoppered bottle to the nearest 60.001 g and
oven drying, (d) shape of the weighing container, and (e) type
record.
of oven (gravity versus mechanical convection) used.
NOTE 1—Since leather varies greatly in moisture content depending
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