ASTM D2495-87(1993)e1
(Test Method)Standard Test Method for Moisture in Cotton by Oven-Drying
Standard Test Method for Moisture in Cotton by Oven-Drying
SCOPE
1.1 This test method covers the determination of the amount of moisture in cotton by oven-drying and is applicable to raw cotton, cotton stock in process, and cotton waste.
1.2 This test method may also, by agreement, be used for determining moisture in blends of cotton with other fibers.
1.3 This test method offers alternative procedures for weighing the dried specimens, one procedure using an oven balance (9.3) and the other using a desiccator (9.4). Note 1-For other methods of determination of moisture in textile materials refer to Test Method D2654, which includes two options based on drying in an oven, and one option based on distillation with an immiscible solvent: Methods D885, Test Method D1576, Test Method D2462.
1.4 The values stated in SI units are to be regarded as the standard. No other units are included in this standard.
1.5 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.
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e1
Designation: D 2495 – 87 (Reapproved 1993)
Standard Test Method for
Moisture in Cotton by Oven-Drying
This standard is issued under the fixed designation D 2495; 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.
e NOTE—Editorial changes were made throughout March 1993.
1. Scope mixture of cotton fibers with foreign matter.
3.1.2 ginned lint (cotton), n—cotton fibers that have been
1.1 This test method covers the determination of the amount
separated from their seeds by ginning but not subjected to any
of moisture in cotton by oven-drying and is applicable to raw
further processing after ginning.
cotton, cotton stock in process, and cotton waste.
3.1.2.1 Discussion—“Ginned lint” and “raw cotton” are
1.2 This test method may also, by agreement, be used for
synonymous; the same material that is called “ginned lint” at
determining moisture in blends of cotton with other fibers.
the ginnery (to distinguish it from seed cotton) is called “raw
1.3 This test method offers alternative procedures for
cotton” when it is received at a textile mill. “Lint cotton” may
weighing the dried specimens, one procedure using an oven
be either raw or processed.
balance (12.3) and the other using a desiccator (12.4).
3.1.3 lint cotton, n—loose cotton fibers in any form, either
NOTE 1—For other methods of determination of moisture in textile
raw or processed, free of seeds and not bound together in yarn
materials refer to Test Method D 2654, which includes two options based
or fabric.
on drying in an oven, and one option based on distillation with an
3.1.4 moisture content, n—the amount of water in a material
immiscible solvent: Methods D 885, Test Method D 1576, Test Method
determined under prescribed conditions and expressed as a
D 2462.
percentage of the mass of the moist material; that is, the
1.4 The values stated in SI units are to be regarded as the
original mass comprising the dry substance plus any water
standard.
present.
1.5 This standard does not purport to address all of the
3.1.4.1 Discussion—The word “water” as used in these
safety problems, if any, associated with its use. It is the
definitions refers to the compound technically defined as H O.
responsibility of the user of this standard to establish appro-
The terms “water” and “moisture” are frequently used inter-
priate safety and health practices and determine the applica-
changeably in the literature and in the trade, but the term
bility of regulatory limitations prior to use.
“moisture” is sometimes considered to include other volatile
materials. Moisture content is also referred to as moisture on
2. Referenced Documents
the “as is,” “as received,” or “wet” basis.
2.1 ASTM Standards:
3.1.5 moisture-free, adj—the condition of a material that
D 123 Terminology Relating to Textiles
has been exposed in an atmosphere of desiccated air until there
D 885 Methods of Testing Tire Cords, Tire Cord Fabrics,
is no further significant change in its mass.
and Industrial Filament Yarns Made from Man-Made
3.1.6 moisture regain, n—the amount of water in a material
Organic-Base Fibers
determined under prescribed conditions and expressed as a
D 1576 Test Method for Moisture in Wool by OvenDrying
percentage of the mass of the water-free specimen. (see also
D 2462 Test Method for Moisture in Wool by Distillation
moisture content)
with Toluene
3.1.6.1 Discussion—Equivalent expressions are “regain,”
D 2654 Test Methods for Moisture in Textiles
moisture on the “moisture-free” or moisture on the “dry” basis,
also moisture on the “oven-dry” basis. Moisture regain calcu-
3. Terminology
lations are commonly based on the mass of a specimen which
3.1 Definitions:
has been dried by heating in an oven. If the air in the oven
3.1.1 cotton waste, n—material removed from seed cotton,
contains moisture, the oven-dried specimen will contain some
ginned lint, or stock in process by any cleaning or processing
moisture even when it no longer undergoes a significant change
machinery and usually consisting of undesirable fibers or of a
in mass following additional drying under the same atmo-
spheric conditions. In order to ensure that the specimen is
This test method is under the jurisdiction of ASTM Committee D-13 on
moisture-free, it must be exposed to desiccated air until it
Textiles, and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers.
shows no significant change in its mass; this procedure can be
Current edition approved July 31, 1987. Published September 1987. Originally
found in Test Method D 2654.
published as D 2945–61 T. Last previous edition D 2945–75 (1980).
Annual Book of ASTM Standards, Vol 07.01. 3.1.7 oven-dry, adj—the condition of a material that has
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 2495
been heated under prescribed conditions of temperature and increases fly waste and may cause manufacturing difficulties
humidity until there is no further significant change in its mass. due to static electricity.
(see moisture regain)
5.3 Variations in the amount of moisture present affect the
3.1.8 percentage point, n—a difference of 1 % of a base mass and hence the market value of a lot of material sold at a
quantity.
definite price per unit mass. Knowledge of the moisture content
3.1.8.1 Discussion—A phrase such as “a difference of X %” or regain can be accordingly an important financial consider-
is ambiguous when referring to a difference in percentages. For
ation.
example, a change in the moisture regain of a material from 5 5.4 Moisture content variation affects lap, sliver, and roving
to 7 % could be reported as an increase of 40 % of the initial
linear density which in turn controls yarn number variation.
moisture regain, or as an increase of two percentage points. 5.5 The mass of the oven-dry specimen used in this method
The latter wording is recommended.
is the mass observed after the specimen has been dried in an
3.1.9 raw cotton, n—ginned lint that has not been subjected oven supplied with ambient air. The observed mass is accord-
to any textile manufacturing process. (see also ginned lint)
ingly subject to minor variations as discussed in 3.6.1. These
3.1.10 seed cotton, n—cotton, as harvested and before variations, however, are believed to be without significance in
ginning, consisting of seeds with the fibers attached and
commercial transactions.
usually including measurable amounts of foreign matter.
3.1.11 stock in process, n—in textiles, staple fibers at any 6. Apparatus
stage of manufacture between the opening of the bale and the
6.1 Oven, thermostatically controlled at a temperature of
completion of the spinning process.
105 6 2°C (220 6 4°F) with fan-forced ventilation and
3.2 For definitions of other textile terms used in this test
preferably equipped with a balance that permits weighing the
method refer to Terminology D 123.
specimens without opening the oven. The air entering the oven
must come from the standard atmosphere for testing textiles.
4. Summary of Test Method
6.2 Balance(s), of sufficient capacity to weigh the speci-
4.1 Specimens are weighed, dried in an oven, and re-
mens in the containers that will be used and having a sensitivity
weighed. The difference between the original mass and the
of 0.01 g.
oven-dry mass is calculated in percent, either as moisture
NOTE 2—Although all the weighing can be done on the oven balance,
content or moisture regain.
it is more convenient and the work can be completed more quickly if a
separate balance is available for weighing the specimens before drying.
5. Significance and Use
Otherwise, the oven must be allowed to cool to room temperature before
5.1 This test method for testing the moisture content of
a new set of specimens can be weighed.
cotton can be used for acceptance testing of commercial
6.3 Weighing Containers, to be used when the specimens
shipments of lint cotton provided the between-laboratory bias
are weighed in the oven (see 12.1.1 and 12.2).
is known.
6.3.1 The weighing containers may be perforated metal
5.1.1 In case of a dispute arising from differences in
baskets or shallow pans, of a size to fit the particular oven in
reported test results when using Test Method D 2495 for
which they are used. For specimens containing particles of
acceptance testing of commercial shipments, the purchaser and
foreign matter that are easily shaken out, use baskets made of
the supplier should conduct comparative tests to determine if
or lined with wire screening fine enough to hold the trash, or
there is a statistical bias between their laboratories. Competent
line the lower part of the basket with metal foil, but this
statistical assistance is recommended for the investigation of
technique may prolong the drying period required.
bias. As a minimum, the two parties should take a group of test
6.3.2 Weighing Bottles or Weighing Cans, with tight-fitting
specimens that are as homogeneous as possible and that are
covers, for use with the desiccator procedure (12.1.2 and 12.4).
from a lot of material of the type in question. The test
To expedite drying, the diameter of each container should be
specimens should then be randomly assigned in equal numbers
greater than its height.
to each laboratory for testing. The average results from the two
6.4 Desiccator, large enough to hold as many weighing
laboratories should be compared using Student’s t-test for
containers as will be dried at one time. (For the desiccator
unpaired data and an acceptable probability level chosen by the
procedure only, see 12.1.2 and 12.4.)
two parties before the testing is begun. If a bias is found, either
6.5 Desiccant—Calcium chloride is satisfactory, provided
its cause must be found and corrected or the purchaser and the
that it is redried or replaced as required for effective desicca-
supplier must agree to interpret future test results in the light of
tion. Any other effective, noncaustic desiccant may be used.
the known bias.
(For the desiccator procedure only, see 12.1.2 and 12.4.)
5.2 Information on the moisture content of cotton is desir-
6.6 Sample Containers—Metal cans, glass jars, or plastic
able since the physical properties of cotton are significantly
affected by its moisture content. High moisture content in- containers of approximately 1-L (1-qt) capacity with airtight
covers are recommended for use when sampling cotton outside
creases flexibility, toughness, elongation, and tensile strength.
the laboratory.
Too high a moisture content causes difficulty in processing due
to the tendency of the stock to “lap-up” on drafting rolls. Low
NOTE 3—For very dry material, that must be weighed in the containers,
moisture, on the other hand, facilitates cleaning but increases
lightweight containers are desirable. For damp cotton, which would rust
the brittleness of the fiber and results in fiber breakage during
tin-plated cans, the containers should be made of rustproof material (such
ginning, cleaning, and mill processing. Low moisture also as aluminum, glass, or plastic).
D 2495
SAMPLING PROCEDURE 9.2.4 In identifying containers or specimens, do not use any
material of variable moisture content. For example, do not
7. Division into Lots
place identifying tags or slips of paper inside the sample
7.1 Unless there is information to the contrary, consider all
containers and do not paste labels on the outside if the
the cotton or cotton products in a single shipment or consign-
specimens are to be weighed in the containers. Identify
ment as a single lot for sampling purposes. If the shipment or
containers by etching, stamping, or by scratching numbers on
consignment contains cotton or cotton products from two or
them, or by marking with crayon, ink, or paint.
more sources, consider the material from each source as a
9.3 Sample Collection:
separate lot.
9.3.1 When sampling lint cotton as it passes through (1) lint
cleaners or condensers in the ginnery, (2) opening and cleaning
8. Lot Sample
machinery in the mill, or (3) mechanical or pneumatic convey-
8.1 Acceptance Testing—As a lot sample for acceptance
ors between machines, take the specimen as the material flows
testing, take at random the number of shipping containers as
past the sampling location. Place it in the sample container
directed in an applicable material specification or other agree-
without delay, and immediately close the container with a
ment between the purchaser and the supplier. In the absence of
tightly fitting cover.
such an agreement take ten shipping containers or 10 % of the
9.3.2 Sliver and roving are usually in approximate moisture
shipping containers in the lot, whichever is the greater.
equilibrium with the air in the mill. Take short sections from a
Consider bales or other shipping containers to be the primary
number of strands as directed in 9.3.1 and place enough of
sampling units.
them in the container so that the total mass is as specified in
NOTE 4—An adequate specification or other agreement between the 9.2. Extreme haste is not necessary, but avoid handling the
purchaser and the supplier requires taking into account the variability
material more than necessary to minimize adsorption of
between shipping containers, between laboratory samples within a ship-
moisture from the hands. Immediately after the sample has
ping container, and between test specimens within a laboratory sample to
been placed in the container, close the latter with a tightly
provide a sampling plan with a meaningful producer’s risk, consumer’s
fitting cover.
risk, acceptable quality level, and limiting quality level.
9.3.3 To sample raw cotton in bales, cut out a section
8.2 Other Testing—Select the lot sample to meet the re-
approximately 0.15 m (6 in.) wide across the bale and at least
quirements of the particular experimental design or purpose of
0.15 m deep from the space between two bale ties. Immediately
the fiber tests desired. Select the lot sample source material in
take the specimen (1) by taking the surface cotton from the
such a manner that it will be as uniform as practicable, on the
bottom of the cavity, or (2) by pulling cotton from the face of
basis of available information. If the lot sample is nonhomo-
the section that was nearest the inside of the bale.
geneous, divide it into rational subgroups; for example, indi-
9.3.4 When the material is far from moisture equilibrium
vidual bales in a commercial shipment, on the basis of
with the surrounding air, seal the containers as quickly as
available
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