ASTM D3106-95a
(Test Method)Standard Test Method for Permanent Deformation of Elastomeric Yarns
Standard Test Method for Permanent Deformation of Elastomeric Yarns
SCOPE
1.1 This test method covers the determination of the permanent deformation of bare, continuous elastomeric monofilaments and filament yarns made from rubber, spandex, anidex, or other elastomers subjected to prolonged periods of tension. This test method is applicable to elastomeric yarns having a linear density in the range from 4 to 320 tex (36 to 2900 den.).
1.2 This test method is not applicable to covered, wrapped, core-spun yarns, or yarns spun from elastomeric staple.
1.3 This test method was developed using yarns in the "as-received" condition, but may be used for treated yarns provided the treatment is specified.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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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Designation: D 3106 – 95a
Standard Test Method for
Permanent Deformation of Elastomeric Yarns
This standard is issued under the fixed designation D 3106; 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 stretched repeatedly at room temperature to at least twice its
original length and which after removal of the tensile force will
1.1 This test method covers the determination of the perma-
immediately and forcibly return to approximately its original
nent deformation of bare, continuous elastomeric monofila-
length.
ments and filament yarns made from rubber, spandex, anidex,
3.2.2.1 Discussion—The elastic properties of the yarn are
or other elastomers subjected to prolonged periods of tension.
produced by the use of filaments, or a core, made from
This test method is applicable to elastomeric yarns having a
polymers having a special chemical composition or molecular
linear density in the range from 4 to 320 tex (36 to 2900 den.).
structure, for example, filaments made from spandex or from
1.2 This test method is not applicable to covered, wrapped,
cut or extruded rubber.
core-spun yarns, or yarns spun from elastomeric staple.
3.2.3 elongation, n—the ratio of the extension of a material
1.3 This test method was developed using yarns in the
to the length of the material prior to stretching.
“as-received” condition, but may be used for treated yarns
3.2.3.1 Discussion—In a tensile test of elastomeric yarns,
provided the treatment is specified.
the percent elongation is usually calculated on the basis of the
1.4 The values stated in SI units are to be regarded as the
nominal gage length of a pretensioned specimen.
standard. The values given in parentheses are for information
3.2.4 elongation at the break, n—the elongation corre-
only.
sponding to the breaking force.
1.5 This standard does not purport to address all of the
3.2.4.1 Discussion—Elongation at the breaking force is the
safety concerns, if any, associated with its use. It is the
change in length of the specimen which results from stretching
responsibility of the user of this standard to establish appro-
the specimen to rupture.
priate safety and health practices and determine the applica-
3.2.5 extension, n—an increase in length or width.
bility of regulatory limitations prior to use.
3.2.6 force, n—a physical influence exerted by one body on
2. Referenced Documents another which produces acceleration of bodies that are not free
to move.
2.1 ASTM Standards:
3.2.7 linear density, n—mass per unit length; the quotient
D 123 Terminology Relating to Textile Materials
obtained by dividing the mass of a fiber or yarn by its length.
D 2433 Test Method for Rubber Thread
3.2.7.1 Discussion—The preferred units of measurement
3. Terminology
are grams per metre, or multiples or submultiples of these. The
tex unit, grams per kilometre, is recommended for yarns.
3.1 Definitions—For definitions of textile terms used in this
3.2.8 permanent deformation, n—the net long-term change
test method, refer to Terminology D 123.
in a dimension of a specimen after deformation and relaxation
3.2 Definitions of Terms Specific to This Standard:
under specified conditions.
3.2.1 breaking force, n—the maximum force applied to a
3.2.8.1 Discussion—Permanent deformation is usually ex-
specimen in a tensile test carried to rupture.
pressed as a percentage of the original dimension. Permanent
3.2.1.1 Discussion—Force is commonly expressed in
deformation is also commonly referred to as “permanent set,”
pounds-force (lbf), newtons (N), or millinewtons (mN). New-
“nonrecoverable deformation,” and “nonrecoverable stretch.”
tons or millinewtons are preferred units.
3.2.2 elastomeric yarn, n—a nontextured yarn that can be
4. Summary of Test Method
4.1 The nominal linear density of the sample is known or
This test method is under the jurisdiction of ASTM Committee D13 on Textiles
determined and the elongation at the breaking force is deter-
and is the direct responsibility of Subcommittee D13.58 on Yarn Test Methods.
mined from representative specimens.
Current edition approved Nov. 10, 1995. Published June 1996. Originally
4.2 A specimen from the sample is placed in a pair of
published as D 3106 – 72 T. Last previous edition D 3106 – 95.
line-contact clamps and held at a selected elongation for a
Annual Book of ASTM Standards, Vol 07.01.
Annual Book of ASTM Standards, Vol 09.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 3106
specified period of time. The permanent deformation or non- the purchaser and the supplier. If differing numbers and
recoverable stretch is measured after a specified recovery packages are to be taken from the shipping cartons in the lot
period. sample, determine at random which shipping cartons are to
have each number of packages drawn.
5. Significance and Use
NOTE 2—An adequate specification or other agreement between the
5.1 Test Method D 3106 for testing permanent deformation
purchaser and the supplier requires taking into account the variability
of elastomeric yarns is considered satisfactory for acceptance between shipping cartons, and the variability of the material within the
shipping carton, to provide a sampling plan with a meaningful producer’s
testing of commercial shipments when there is prior agreement
risk, consumer’s risk, acceptable quality level, and limiting quality level.
as to the exact value of elongation to be used for testing, since
current estimates of between-laboratory precision are accept-
7.3 Test Specimens—From each package in the laboratory
able.
sample, take the number of specimens directed in Section 8.
5.1.1 In case of a dispute arising from differences in
Inspect each package after withdrawing at least five layers of
reported test results when using Test Method D 3106 for
yarn from the outside of the package. If there is evidence of
acceptance testing of commercial shipments, the purchaser and
damage, continue to withdraw units of five layers and reinspect
the supplier should conduct comparative tests to determine if
until there is no discernible damage. Withdraw yarn over the
there is a statistical bias between their laboratories. Competent
end of the package and cut specimens approximately 150 mm
statistical assistance is recommended for the investigation of
long. Discard specimens that are damaged during withdrawal
bias. As a minimum, the two parties should take a group of test
or cutting. Withdraw at least2mof yarn between specimens
specimens that are as homogeneous as possible and that are
from a single package.
from a lot of material of the type in question. The test
8. Specimens Per Package
specimens should then be randomly assigned in equal numbers
to each laboratory for testing. The average results from the two 8.1 Take a number of specimens per package such that the
laboratories should be compared using Student’s t-test for user may expect at the 95 % probability level that the test result
unpaired data and an acceptable probability level chosen by the is no more than 0.55 percentage points above or below the true
two parties before the testing is begun. If bias is found, either average of the package. Determine the number of specimens as
its cause must be found and corrected or the purchaser and the follows:
supplier must agree to interpret future test results in the light of 8.1.1 Reliable Estimate of s—When there is a reliable
the known bias. estimate of s based on extensive past records for similar
5.2 Yarns are subjected to long periods of tension resulting materials tested in the user’s laboratory as directed in the test
in an appreciable amount of stretch during normal use. A method, calculate the required number of specimens per
portion of the induced stretch may be permanent. The amount package using (Eq 1):
of permanent deformation is influenced by the amount of
n 5 ts/E! (1)
~
tension, the time the yarn is under tension and the time
available for recovery between successive uses. where:
5.3 For optimum processing of elastomeric yarns, the per- n = number of specimens per package (rounded upward to
manent deformation value should be low or zero.
a whole number),
s = reliable estimate of the standard deviation of indi-
6. Apparatus
vidual observations on similar materials in the user’s
laboratory under conditions of single-operator preci-
6.1 Line-Contact Clamps, with one fixed clamp and one
sion,
movable clamp, assembled as directed in Appendix X1, and as
t = value of Student’s t for two-sided limits, a 95 %
shown in Fig. 1.
probability level, and the degree of freedom associated
6.2 Tensioning Weights, 10 mg to 3 g, to pretension the
with the estimate of s (see Table 1), and
specimens before final clamping.
E = 0.55 percentage points, the value of the allowable
NOTE 1—Aluminum foil has been found to be suitable for use as
variation.
tensioning weights; the foil may be attached to the yarn by folding it over
8.1.2 No Reliable Estimate of s—When there is no reliable
the yarn.
estimate of s for the user’s laboratory, (Eq 1) should not be
6.3 Stop Watch or Timer.
used directly. Instead, specify the fixed number of ten speci-
mens. This number of specimens is calculated using s = 0.87
7. Sampling
percentage point, which is a somewhat larger value of s than is
7.1 Lot Sample—As a lot sample for acceptance testing,
usually found in practice. When a reliable estimate of s for the
take at random the number of shipping cartons of elastomeric
user’s laboratory becomes available, (Eq 1) will usually require
yarn as directed in the applicable material specification or other
fewer than ten specimens.
agreement between the purchaser and supplier. Consider the
9. Conditioning
material shipping carton to be the primary sampling unit.
7.2 Laboratory Sample—As a laboratory sample for accep- 9.1 Condition the specimens in the standard atmosphere for
tance testing, take at random the number of packages from testing textiles, 65 6 2 % relative humidity and 21 6 1°C (70
each shipping carton in the lot sample as directed in the 6 2°F) temperature, in moving air for a minimum time of 16
applicable material specification or other agreement between h. Preconditioning is not necessary for the currently produced
D 3106
FIG. 1 Test Apparatus for Permanent Set
A
TABLE 1 Values of Student’s t for One-Sided and Two-Sided Limits and the 95 % Probability Level
dF One-sided Two-sided dF One-sided Two-sided dF One-sided Two-sided
1 6.314 12.706 11 1.796 2.201 22 1.717 2.074
2 2.920 4.303 12 1.782 2.179 24 1.711 2.064
3 2.353 3.182 13 1.771 2.160 26 1.706 2.056
4 2.1
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