ASTM D2968-95
(Test Method)Standard Test Method for Med and Kemp Fibers in Wool and Other Animal Fibers by Microprojection
Standard Test Method for Med and Kemp Fibers in Wool and Other Animal Fibers by Microprojection
SCOPE
1.1 This test method covers the determination by microprojection of the percentage of medullated fibers (med and kemp fibers) in wool or other animal fibers such as mohair, cashmere, alpaca, or camel's hair in their various forms.
1.2 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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Designation: D 2968 – 95
Standard Test Method for
Med and Kemp Fibers in Wool and Other Animal Fibers by
Microprojection
This standard is issued under the fixed designation D 2968; 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 med and kemp fibers are expressed as percentages of the total
number of fiber images examined.
1.1 This test method covers the determination by micro-
projection of the percentage of medullated fibers (med and
5. Significance and Use
kemp fibers) in wool or other animal fibers such as mohair,
5.1 Test Method D 2968 for the determination of med and
cashmere, alpaca, or camel’s hair in their various forms.
kemp fibers by microprojection may be used for the acceptance
1.2 This standard does not purport to address all of the
testing of commercial shipments of wool and other animal
safety concerns, if any, associated with its use. It is the
fibers, but caution is advised since only a few types of animal
responsibility of the user of this standard to establish appro-
fibers have been subjected to interlaboratory tests to ascertain
priate safety and health practices and determine the applica-
the precision of tests for med and kemp fibers by this test
bility of regulatory limitations prior to use.
method. Comparative tests as directed in 5.1.1 may be advis-
2. Referenced Documents able.
5.1.1 In case of a dispute arising from differences in
2.1 ASTM Standards:
reported test results when using Test Method D 2968 for
D 123 Terminology Relating to Textile Materials
acceptance testing of commercial shipments, the purchaser and
D 2130 Test Method for Diameter of Wool and Other
the supplier should conduct comparative tests to determine if
Animal Fibers by Microprojection
there is a statistical bias between their laboratories. Competent
3. Terminology
statistical assistance is recommended for the investigation of
bias. As a minimum, the two parties should take a group of test
3.1 Definitions—For definitions of other textile terms used
specimens which are as homogeneous as possible and which
in this test method, refer to Terminology D 123.
are from a lot of material of the type in question. The test
3.2 Definitions of Terms Specific to This Standard:
specimens should then be randomly assigned in equal numbers
3.2.1 kemp fiber, n—a medullated animal fiber in which the
to each laboratory for testing. The average results from the two
diameter of the medulla is 60 %, or more, of the diameter of the
laboratories should be compared using Student’s t-test for
fiber.
unpaired data and an acceptable probability level chosen by the
3.2.2 med fiber, n—a medullated animal fiber in which the
two parties before testing is begun. If a bias is found, either its
diameter of the medulla is less than 60% of the diameter of the
cause must be found and corrected, or the purchaser and the
fiber.
supplier must agree to interpret future test results in view of the
3.2.3 medulla, n—in mammalian hair fibers, the more or
known bias.
less continuous cellular marrow inside the cortical layer in
5.2 Knowledge of the incidence of med fibers and kemp
most medium and coarse fibers.
fibers in wool and other animal fibers is of importance to
3.2.4 medullated fiber, n—an animal fiber that in its original
manufacturers of woven or knitted fabrics because of the
state includes a medulla.
apparent dye resistance and light reflectance qualities of these
3.2.5 wool, n—the fibrous covering of the sheep, ovis
fibers. This is not to imply that all kemp fibers will resist dye
species.
and all med fibers will accept dye normally. In practice, a
4. Summary of Test Method
proportion of kemp fibers will appear normal after dyeing and
a proportion of med fibers will appear chalky white after
4.1 The magnified images of a specimen of the animal fibers
dyeing. From the perspective of visual and aesthetic problems,
are examined. All medullated fibers are measured and classed
medullated fibers having an abnormally large diameter and a
as either med fibers or kemp fibers. The observed numbers of
high degree of medullation are probably the worst kind.
This test method is under the jurisdiction of ASTM Committee D-13 on Textiles
6. Apparatus and Material
and is the direct responsibility of Subcommittee D13.13 on Wool and Wool Felt.
6.1 The apparatus and material required in this test method
Current edition approved Sept. 10, 1995. Published December 1995. Originally
published as D 2968 – 71 T. Last previous edition D 2968 – 89.
are identical to those specified in Test Method D 2130.
Annual Book of ASTM Standards, Vol 07.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 2968
NOTE 1—The contrast between the solid and the hollow portions of the medullated fibers is significantly reduced when the medulla becomes filled with
mounting medium.
FIG. 1 Types of Medulla in Wool and Mohair Fibers
7. Sampling Method D 2968. Describe the material or product sampled and
the method used.
7.1 Adequate sampling procedures for loose fibers (grease,
10.2 Report the following information:
pulled, and scoured), sliver, top, yarn, and fabric are described
10.2.1 The med fibers content,
in Test Method D 2130.
10.2.2 The kemp fibers content, and
8. Procedure
10.2.3 The total number of animal fibers observed.
8.1 Prepare the test specimens, calibrate the microprojector,
11. Precision and Bias
condition the specimens, and prepare the slides by use of the
heavy-duty cross-section device as directed in Test Method 11.1 Interlaboratory Test Data —An interlaboratory test
was conducted in 1970 in which three randomly drawn samples
D 2130. Have two operators independently prepare at least one
slide for each test specimen. from one lot of mohair top were tested in each of five
laboratories. Two operators in each laboratory each examined
8.2 Have each of the two operators make observations using
the procedure specified in Test Method D 2130, except that 500 fibers per sample. The test results for med fibers and kemp
fibers were found to be free of bias due to sampling or testing
only medullated fibers need be measured. For such fibers,
measure the diameter of both the medulla and the fiber, errors for nine of the ten operators involved.
11.1.1 Interlaboratory test data are on file only for mohair
calculate the
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