Standard Test Method for Grain Crack and Extension of Leather by the Mullen Test

SIGNIFICANCE AND USE
4.1 The test method is designed to measure the force required to crack the grain of leather by steady hydraulic pressure on a diaphragm of definite diameter applied to the flesh side of the specimen to form a sphere. The cracking of the grain is a result of failure under elongation or stretch. The elongation or stretch of the leather can be measured at different loads or at the failure of the grain to determine if the stress leather will withstand under lasting conditions. Cuts, scratches, and other defects will cause considerable variation in the results by concentration of the applied force to the weak points. This test method is excellent for manufacturing control, specification acceptance, and service evaluation in the lasting property of leather. This test method may not apply when the conditions of the test employed differ widely from those specified in the test method.
SCOPE
1.1 This test method covers the determination of the resistance of leather to grain cracking and for measuring the extension of the leather. It is limited to light leathers such as shoe uppers, garment, gloves, and upholstery. This test method does not apply to wet blue.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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.

General Information

Status
Historical
Publication Date
31-Aug-2012
Technical Committee
Drafting Committee
Current Stage
Ref Project

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ASTM D2210-00(2012) - Standard Test Method for Grain Crack and Extension of Leather by the Mullen Test
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation: D2210 − 00 (Reapproved2012)
Standard Test Method for
Grain Crack and Extension of Leather by the Mullen Test
This standard is issued under the fixed designation D2210; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 4. Significance and Use
1.1 This test method covers the determination of the resis-
4.1 The test method is designed to measure the force
tance of leather to grain cracking and for measuring the required to crack the grain of leather by steady hydraulic
extension of the leather. It is limited to light leathers such as
pressure on a diaphragm of definite diameter applied to the
shoe uppers, garment, gloves, and upholstery.This test method fleshsideofthespecimentoformasphere.Thecrackingofthe
does not apply to wet blue.
grain is a result of failure under elongation or stretch. The
elongationorstretchoftheleathercanbemeasuredatdifferent
1.2 The values stated in inch-pound units are to be regarded
loads or at the failure of the grain to determine if the stress
as standard. The values given in parentheses are mathematical
leatherwillwithstandunderlastingconditions.Cuts,scratches,
conversions to SI units that are provided for information only
and other defects will cause considerable variation in the
and are not considered standard.
resultsbyconcentrationoftheappliedforcetotheweakpoints.
1.3 This standard does not purport to address all of the
This test method is excellent for manufacturing control, speci-
safety concerns, if any, associated with its use. It is the
fication acceptance, and service evaluation in the lasting
responsibility of the user of this standard to establish appro-
property of leather. This test method may not apply when the
priate safety and health practices and determine the applica-
conditions of the test employed differ widely from those
bility of regulatory limitations prior to use.
specified in the test method.
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
5.1 Testing Machine, asshowninFig.1.Themachineshall
D1610Practice for Conditioning Leather and Leather Prod-
be hand- or power-driven. The machine shall hold the speci-
ucts for Testing
men firmly, without slippage, between two annular, plane,
D1813Test Method for Measuring Thickness of Leather
unpolished (matte) surfaces that may have fine, spiral tool
Test Specimens
marks not over 0.010 in. (0.25 mm) in depth.
5.2 Upper Clamping Surface—The upper clamping surface
3. Terminology
(clampingring)shallhaveacircularopening1.240 60.010in.
3.1 Definitions:
(31.50 6 0.25 mm) in diameter and shall be connected to the
3.1.1 extension—the amount of stretch of leather over the
clamping mechanism through a swivel joint to ensure an even
diaphragm under pressure.
clamping pressure.
3.1.2 grain cracking—the appearance of cracks on the
5.3 Lower Clamping Surface—The lower clamping surface
surface of the leather as the leather is extended over a
(diaphragmplate)shallbe0.219 60.003in.(5.56 60.08mm)
diaphragm under pressure to form a sphere.
thick and have an opening of 1.240 6 0.01 in. (31.50 6 0.52
mm) in diameter.The circular edges of the openings that come
incontactwiththespecimenandtherubberdiaphragmshallbe
This test method is under the jurisdiction ofASTM Committee D31 on Leather
rounded to a radius of not over 0.025 in. (0.64 mm) to prevent
and is the direct responsibility of Subcommittee D31.03 on Footwear. This test
any cutting action. During the test, the circular edges of the
method was developed in cooperation with the American Leather Chemists Assn.
(Standard Method E58–1965).
Current edition approved Sept. 1, 2012. Published September 2012. Originally
approved in 1963 as D2210–63T. Last previous edition approved in 2008 as
D2210–00(2008). DOI: 10.1520/D2210-00R12. The sole source of supply of the apparatus known to the committee at this time
For referenced ASTM standards, visit the ASTM website, www.astm.org, or is B. F. Perkins, 939 Chicopee St., Chicopee, MA 01013-2797, (413) 536-1311. If
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM you are aware of alternative suppliers, please provide this information to ASTM
Standards volume information, refer to the standard’s Document Summary page on Headquarters.Your comments will receive careful consideration at a meeting of the
the ASTM website. responsible technical committee, which you may attend.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2210 − 00 (2012)
FIG. 1 Mullen Tester, Model A
openings in the two clamping plates shall be substantially maximum capacity.The capacity of the gage shall be such that
concentric with no overlapping of any point. the individual readings will be not less than 25% nor more
than 75% of the total capacity of the gage.
5.4 Diaphragm, of rubber, 0.034 6 0.002 in. (0.86 6 0.05
mm) thick, clamped under the lower clamping plate so that, 5.7 Pressure Control—The machine shall be equipped with
beforethediaphragmisstretchedbypressureunderneathit,the means of applying controlled increasing hydraulic pressure to
center of its upper surface is below the plane of the clamping the underside of the diaphragm until the specimen cracks.This
surface. pressureshallbegeneratedbyapistonforcingaliquor(usually
glycerin) into the pressure chamber of the apparatus. For
5.5 Dial Gage, as shown in Fig. 2, to measure the extension
machines shown in Fig. 1 where the cracking pressure is the
of the leather specimen and mounted on the machine through
only measurement, the pressure will be generated by pumping
screw shaft or on side of clamps on platform. This gage shall
liquid at a rate of 170 6 10 mL/min or by turning a handwheel
becalibratedtoreaddirectlytothenearest0.001in.(0.03mm).
atapproximately30r/min.FormachinesshowninFig.2where
It shall be equipped with a flat anvil and a presser foot.
cracking pressure and extension are measured, the pressure
5.6 Bourdon Tube—The apparatus shall be equipped with a
willbegeneratedbypumpingliquidatarateof15 62mL/min
Bourdon tube, maximum-reading-type, pressure gage gradu-
or by turning a handwheel at approximately 3 r/min.
ated in pounds-force per square inch and accurate throughout
5.8 Thickness Gage—Adead-weight type of thickness gage
the entire range of its scale to within a value of 1% of its
as described in Test Method D1813.
6. Test Specimen
6.1 The specimen shall be a square of leather 3 by 3 in. (76
by 76 mm) cut from the test unit of leather.
6.2 The specimen shall be free of mechanical damage and
surface defects.
7. Conditioning
7.1 All specimens shall be conditioned for 48 h in an
atmosphere maintained at 73.4 6 1.8°F (23 6 1°C) and 50 6
4% relative humidity and tested under these conditions as
described in Practice D1610.
8. Procedure
8.1 Determine the thickness of the specimen by taking three
measurements in the area to be cracked and determine the
average value.
8.2 Place the flesh side of the specimen in contact with the
FIG. 2 Mullen Tester with Dial Gage rubber diaphragm of the testing machine.
D2210 − 00 (2012)
8.3 Clamp the specimen securely in the apparatus in such a 10.1.1 One Operator, Duplicate Specimens, Same Skin—
manner that the leather will not be damaged. Results by the same operator in duplicate adjacent specimens
inaskintakenfromtheofficialsamplingpositionshouldnotbe
8.4 Rest the presser foot of the extension gage on the flat
considered suspect unless the coefficient of variation exceeds:
surface of the specimen and set the gage at zero.
Extension at Grain
8.5 Apply pressure to the specimen until the specimen
Leathers Cracking Pressure, psi Crack, %
cracks.
Shoe upper 26 13
8.6 At the moment the first crack appears in the specimen
Upholstery 17 14
A
Calfskin 16 22
stop the machine, note the applied pressure from the gage, and
Glove 11 20
record the value as the cracking strength of the specimen.
A
3 ± 1 oz, 0.0468 ± 0.0156 in. (1.189 ± 0.396 mm).
9. Report
10.1.2 Two Laboratories, Duplicate Specimens, Same
9.1 The report shall include the following:
Skin—Results for the same group of light leathers listed in
9.1.1 Cracking pressure to the nearest 5 psi (35 kPa) for
10.1.1 submitted by each of two laboratories on duplicate
each specimen or averaged and reported as the average of the
adjacent specimens in a skin taken from the official sampling
test unit,
position should not be considered suspect unless the two
9.1.2 Extension of the leather to the nearest 0.001 in. (0.03
average results differ by more than 5%.
mm), converted to percentage (see AnnexA1) and reported as
NOTE 1—The reproducibility reported in 10.1.2 is based on data
percentage stretch, and
obtained at two laboratories, and a different operator. The results show
9.1.3 Thickness to the nearest 0.001 in. (0.03 mm) reported
close correlation between laboratories.
for each specimen or averaged and reported as the thickness of
NOTE 2—The results given in Section 10 are based on tests on 30 sides
the sample.
of leather and do not apply to findings and cut parts.
9.1.4 Speed the liquid was pumped to build press
...

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