ASTM D7025-04
(Test Method)Standard Test Method for Assessing Clean Flax Fiber Fineness
Standard Test Method for Assessing Clean Flax Fiber Fineness
SCOPE
1.1 This test method provides two options that cover the determination of the fineness of clean loose flax fibers by: Option 1, measuring the specific surface area by the resistance of a plug of flax fibers to air flow under prescribed conditions, or Option 2, estimating the mass per unit length.
1.2 The values, stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation:D7025–04
Standard Test Method for
Assessing Clean Flax Fiber Fineness
This standard is issued under the fixed designation D 7025; 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 D 2480 Method of Test for Maturity Index and Linear
Density of Cotton Fibers by the Causticaire Method
1.1 This test method provides two options that cover the
D 3510 Test Method for Diameter of Wool and Other
determination of the fineness of clean loose flax fibers by:
Animal Fibers by Image Analyser
Option 1, measuring the specific surface area by the resistance
D 6798 Terminology Relating to Flax and Linen
of a plug of flax fibers to air flow under prescribed conditions,
or Option 2, estimating the mass per unit length.
3. Terminology
1.2 The values, stated in SI units are to be regarded as
3.1 Definitions:
standard. No other units of measurement are included in this
3.1.1 fineness index, n—the use of a cellulosic fiber to
standard.
measure air permeability having a specific gravity of 1.5 and a
1.3 This standard does not purport to address all of the
nominal linear density of 1.1 denier, 1.5 denier, or 3.0 denier.
safety concerns, if any, associated with its use. It is the
3.1.1.1 Discussion—Viscose rayon fiber samples are less
responsibility of the user of this standard to establish appro-
variable than natural fibers and manufactured to exacting
priate safety and health practices and determine the applica-
properties by many fiber distributors. These fibers are derived
bility of regulatory limitations prior to use.
from regenerated cellulose to contain a chemically induced
2. Referenced Documents crimp (4 to 6 crimps/cm) and a staple length of approximately
5 cm. Linear density of these fibers can be verified using the
2.1 ASTM Standards:
bundle weighing Option A of Test Method D 1577 to be
D 123 Terminology Relating to Textiles
approximately 0.11, 0.17, and 0.33 mg/m. As detailed in Test
D 1059 Test Method for Yarn Number Based on Short-
Method D 1577, fibers were cut with a mechanical cutting
Length Specimens
device under sufficient tension to remove fiber crimp. These
D 1282 Test Method for Resistance to Airflow as an Indi-
cellulosic fibers have the same specific gravity as flax and can
cation of Average Fiber Diameter of Wool Top, Card
be used to determine the specific surface area.
Sliver, and Scoured Wool
3.1.2 specific surface index, n—relative fineness obtained
D 1441 Practice for Sampling Cotton Fibers for Testing
by measuring the specific surface area by the resistance of
D 1444 Test Method for Cross-Sectional Characteristics of
airflow through a known mass of fiber compressed to a fixed
Cotton Fibers
volume.
D 1448 Test Method for Micronaire Reading of Cotton
3.1.2.1 Discussion—The specific surface index is influ-
Fibers
enced by various types of flax whose fiber perimeter, fiber
D 1449 Test Method for Specific Area and Immunity Ratio
bundles, cross-sectional shape, density, and trash differ be-
of Cotton Fibers (Arealometer Method)
tween samples.
D 1577 Test Method for Linear Density of Textile Fibers
3.2 For definitions of textile terms used in this test method,
D 1769 Test Method for Linear Density of Cotton Fibers
refer to Terminology D 6798.
(Array Sample)
3.3 For definitions of other terms used in this test method,
D 1776 Practice for Conditioning and Testing Textiles
refer to Terminology D 123.
D 2130 Test Method for Diameter of Wool and Other
Animal Fibers by Microprojection
4. Summary of Test Method
4.1 Using Option 1, a predetermined mass of clean loose
This test method is under the jurisdiction ofASTM Committee D13 onTextiles flaxfibersgeneratedbyusingamechanicalblenderisplacedin
and is the direct responsibility of Subcommittee D13.17 on Flax and Linen Fibers.
the specimen holder and compressed to a fixed volume.
Current edition approved May 1, 2004. Published June 2004.
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
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
D7025–04
4.1.1 The resistance to airflow is measured using a cotton 5.4.1 This specific surface index reading is related to the
fiber instrument that provides a reading. This reading is average linear density of single fibers in a bundle calculated
converted to a specific surface index which is derived from the from mass and length measurements on the bundle and the
linear density of flax. number of single fibers in the bundle.
4.2 Using Option 2, the average linear density of single
5.5 The specific surface index of flax fibers may be a
fibers in a bundle is calculated from mass and length measure-
function of fineness, degree of retting, cleanliness, variety,
ments on the bundle and the number of single fibers in the
bundle separation, and plant maturity harvest date. This fine-
bundle.
ness of flax fibers affects their mill processing and spinning
performance as well as contributes significantly to the appear-
NOTE 1—There may be no overall correlation between the results
ance and strength of the yarns produced.
obtained with Options 1 and 2. Consequently, these two options cannot be
used interchangeably. In case of controversy, Option 1 shall prevail.
5.6 The accuracy of weighing can be controlled by the
number of fibers composing the bundle. However, with short
5. Significance and Use
fiber of low linear density the number of fibers to be counted
5.1 This test method for determining fineness of cleaned
becomes prohibitive unless the bundle mass is kept low.
flax fibers is considered satisfactory for acceptance testing of
commercial shipments when the levels are controlled by use of
6. Apparatus and Materials
a range of calibration standards.
6.1 Air-Flow Instrument, a device calibrated in micronaire
5.1.1 If there are differences of practical significance be-
readings or yielding numerical readings from which specific
tween reported test results for two or more laboratories,
surface index readings can be computed.
comparative tests should be performed by those laboratories to
6.2 Balances, with one having a capacity suitable for mass
determine if there is a statistical bias between them, using
of the specific surface index specimen to be used and sensitiv-
competent statistical assistance. As a minimum, use test
ity of at least 0.2 % of the mass and another for linear density
samples that are as homogenous as possible, are drawn from
havingacapacityof15mgandsensitivityofatleast0.005mg.
the material from which the disparate test results were ob-
6.3 Air Supply,tofurnishtherequiredpressureorvacuumto
tained, and are randomly assigned in equal numbers to each
operate the instrument in accordance with the manufacturer’s
laboratory for testing. These test results from the two labora-
instructions.
tories should be compared using a statistical test for unpaired
data, at a probability level chosen prior to the testing series. If 6.4 Fineness Calibration Standards, viscose rayon fibers
a bias is found, either its cause must be found and corrected, or reducedto5cmwithanominallineardensityof1.1,1.5,or3.0
denier and a nominal specific surface fineness index value of
future test results for that material must be adjusted in
consideration of the known bias. 2.55, 2.9, or 4.0.
5.2 The resistance that a plug of flax fibers offers to the flow
6.5 Mechanical Cutting Device, Template, Stelometer
of air is measured as an approximate indication of the average
Clamps, or Die,havingaprecisionof0.1 %designedtopermit
relative fineness of the fibers.
cutting fibers of a specified length.
5.2.1 The total surface area of finer fibers has a larger per
6.6 Stationary Coarse Comb, approximately 63 mm in
unit mass and increased resistance to airflow than do coarser
width and having needles approximately 12.5 mm in length
fibers.
and spaced 19 needles to the centimeter.
5.3 Instruments are available to indicate the resistance to air
6.7 Mechanical Blender, to open and blend the flax fibers.
flow using either compressed air or a vacuum; and are
constructed (1) to measure airflow under constant pressure
7. Sampling and Selection of Specimens
drop across the plug, (2) to measure pressure drop when a
7.1 Take the test specimen by random sampling from the
constant flow of air is maintained, or (3) to indicate resistance
laboratory sample prepared as recommended in Practice
to air flow from both a balanced and unbalanced Wheatstone
D 1441.
bridge.
7.1.1 Pass the test specimen through a mechanical blender
5.4 The reliability of the results of any test method depends
to open and blend fibers as directed in 6.1 of recommended
primarily upon how well the specimens tested represent the
Practice D 1441.
original source material. Flax fibers are different from many
textile fibers, such as cotton or synthetic ones, in that they are
8. Conditioning
not individual filaments but bundles of fibrous material that
may or may not be completely separated into individual
8.1 Bring the laboratory sample from the prevailing atmo-
filamentsandthereforehaveahighdegreeofvariability.While
sphere to moisture equilibrium for testing which is 21 6 1°C
cleaning and processing can produce separation and changes in
(70 6 2°F) and 65 6 2 relative humidity and check the
length, there is no certainty of fibrillation of the fibrous
equilibrium as directed in Practice D 1776. No preconditioning
material.
is required.
NOTE 2—Amodification of this test method can be used in commercial
trading to select bales that will conform to contract guarantees for
specified specific surface index. For this purpose, the usual practice to test
only one specimen per sample. Apparatus and accessories are commercially available.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
D7025–04
OPTION 1: SPECIFIC SURFACE INDEX FINENESS
J = 2.023.
Factors determined by linear regression between resistance
...
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