ASTM D2210-00(2008)

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

SIGNIFICANCE AND USE
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 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-2008
• ICS: 59.140.30 - Leather and furs
• Technical Committee: D31 - Leather
• Drafting Committee: D31.03 - Footwear

Relations

• Replaces: ASTM D2210-00(2004) - Standard Test Method for Grain Crack and Extension of Leather by the Mullen Test
• Effective Date: 01-Sep-2008
• Replaced By: ASTM D2210-00(2012) - Standard Test Method for Grain Crack and Extension of Leather by the Mullen Test
• Effective Date: 01-Sep-2012
• Referred By: ASTM D2322-14(2023) - Standard Test Method for Resistance of Shoe Upper Leather to Artificial Perspiration
• Effective Date: 01-Sep-2008

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D2210 − 00 (Reapproved2008)
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 fleshsideofthespecimentoformasphere.Thecrackingofthe
grain is a result of failure under elongation or stretch. The
1.1 This test method covers the determination of the resis-
elongationorstretchoftheleathercanbemeasuredatdifferent
tance of leather to grain cracking and for measuring the
loads or at the failure of the grain to determine if the stress
extension of the leather. It is limited to light leathers such as
leatherwillwithstandunderlastingconditions.Cuts,scratches,
shoe uppers, garment, gloves, and upholstery.This test method
and other defects will cause considerable variation in the
does not apply to wet blue.
resultsbyconcentrationoftheappliedforcetotheweakpoints.
1.2 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.
3. Terminology
5.2 Upper Clamping Surface—The upper clamping surface
(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
4. Significance and Use
mm) in diameter.The circular edges of the openings that come
incontactwiththespecimenandtherubberdiaphragmshallbe
4.1 The test method is designed to measure the force
rounded to a radius of not over 0.025 in. (0.64 mm) to prevent
required to crack the grain of leather by steady hydraulic
any cutting action. During the test, the circular edges of the
pressure on a diaphragm of definite diameter applied to the
openings in the two clamping plates shall be substantially
concentric with no overlapping of any point.
This test method is under the jurisdiction ofASTM Committee D31 on Leather
5.4 Diaphragm, of rubber, 0.034 6 0.002 in. (0.86 6 0.05
and is the direct responsibility of Subcommittee D31.03 on Footwear. This test
mm) thick, clamped under the lower clamping plate so that,
method was developed in cooperation with the American Leather Chemists Assn.
(Standard Method E58–1965).
Current edition approved Sept. 1, 2008. Published December 2008. Originally
approved in 1963 as D2210–63T. Last previous edition approved in 2004 as
D2210–00(2004). DOI: 10.1520/D2210-00R08. 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, [phone]. If
contact ASTM Customer Service at [e-mail]. 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 (2008)
FIG. 1 Mullen Tester, Model A
beforethediaphragmisstretchedbypressureunderneathit,the 5.7 Pressure Control—The machine shall be equipped with
center of its upper surface is below the plane of the clamping means of applying controlled increasing hydraulic pressure to
surface. the underside of the diaphragm until the specimen cracks.This
pressureshallbegeneratedbyapistonforcingaliquor(usually
5.5 Dial Gage, as shown in Fig. 2, to measure the extension
glycerin) into the pressure chamber of the apparatus. For
of the leather specimen and mounted on the machine through
machines shown in Fig. 1 where the cracking pressure is the
screw shaft or on side of clamps on platform. This gage shall
only measurement, the pressure will be generated by pumping
becalibratedtoreaddirectlytothenearest0.001in.(0.03mm).
liquid at a rate of 170 6 10 mL/min or by turning a handwheel
It shall be equipped with a flat anvil and a presser foot.
atapproximately30r/min.FormachinesshowninFig.2where
5.6 Bourdon Tube—The apparatus shall be equipped with a
cracking pressure and extension are measured, the pressure
Bourdon tube, maximum-reading-type, pressure gage gradu-
willbegeneratedbypumpingliquidatarateof15 62mL/min
ated in pounds-force per square inch and accurate throughout
or by turning a handwheel at approximately 3 r/min.
the entire range of its scale to within a value of 1% of its
5.8 Thickness Gage—Adead-weight type of thickness gage
maximum capacity.The capacity of the gage shall be such that
as described in Test Method D1813.
the individual readings will be not less than 25% nor more
than 75% of the total capacity of the gage.
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
rubber diaphragm of the testing machine.
8.3 Clamp the specimen securely in the apparatus in such a
FIG. 2 Mullen Tester with Dial Gage manner that the leather will not be damaged.
D2210 − 00 (2008)
8.4 Rest the presser foot of the extension gage on the flat inaskintakenfromtheofficialsamplingpositionshouldnotbe
surface of the specimen and set the gage at zero. considered suspect unless the coefficient of variation exceeds:
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
stop the machine, note the applied pressure from the gage, and
Calfskin 16 22
record the value as the cracking strength of the specimen. Glove 11 20
A
9. Report
3 ± 1 oz, 0.0468 ± 0.0156 in. (1.189 ± 0.396 mm).
9.1 The report shall include the following:
10.1.2 Two Laboratories, Duplicate Specimens, Same
9.1.1 Cracking pressure to the nearest 5 psi (35 kPa) for
Skin—Results for the same group of light leathers listed in
each specimen or averaged and reported as the average of the
10.1.1 submitted by each of two laboratories on duplicate
test unit,
adjacent specimens in a skin taken from the official sampling
9.1.2 Extension of the leather to the nearest 0.001 in. (0.03
position should not be considered suspect unless the two
mm), converted to percentage (see AnnexA1) and reported as
average results differ by more than 5%.
percentage stretch, and
NOTE 1—The reproducibility reported in 10.1.2 is based on data
9.1.3 Thickness to the nearest 0.001 in. (0.03 mm) reported
obtained at two laboratories, and a different operator. The results show
for each specimen or averaged and reported as the thickness of
close correlation between laboratories.
the sample.
NOTE 2—The results given in Section 10 are based on tests on 30 sides
9.1.4 Speed the liquid was pumped to build pressure to the
of leather and do not apply to findings and cut parts.
nearest 10% (see 5.7).
NOTE3—Theprecisiondataforbetweenskinsarenotincludedbecause
the results were based on different skins from several production lots.The
10. Precision and Bias
variables in leather for between
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D2210–00(Reapproved 2004) Designation:D2210–00(Reapproved 2008)
Standard Test Method for
Grain Crack and Extension of Leather by the Mullen Test
This standard is issued under the fixed designation D 2210; 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
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 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.
2. Referenced Documents
2.1 ASTM Standards:
D 1610 Practice for Conditioning Leather and Leather Products for Testing
D 1813 Test Method for Measuring Thickness of Leather Test Specimens
3. Terminology
3.1 Definitions:
3.1.1 extension—the amount of stretch of leather over the diaphragm under pressure.
3.1.2 grain cracking—the appearance of cracks on the surface of the leather as the leather is extended over a diaphragm under
pressure to form a sphere.
4. 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.
5. Apparatus
5.1 Testing Machine, as shown in Fig. 1. The machine shall be hand- or power-driven. The machine shall hold the specimen
firmly, without slippage, between two annular, plane, unpolished (matte) surfaces that may have fine, spiral tool marks not over
0.010 in. (0.25 mm) in depth.
5.2 Upper Clamping Surface—The upper clamping surface (clamping ring) shall have a circular opening 1.240 6 0.010 in.
(31.50 6 0.25 mm) in diameter and shall be connected to the clamping mechanism through a swivel joint to ensure an even
clamping pressure.
5.3 Lower Clamping Surface—The lower clamping surface (diaphragm plate) shall be 0.219 6 0.003 in. (5.56 6 0.08 mm)
This test method is under the jurisdiction of ASTM Committee D31 on Leather and is the direct responsibility of Subcommittee D31.03 on Footwear. This test method
was developed in cooperation with the American Leather Chemists Assn. (Standard Method E 58 – 1965).
Current edition approved Sept. 1, 2004.2008. Published September 2004.December 2008. Originally approved in 1963 as D 2210 – 63T. Last previous edition approved
in 20002004 as D 2210 – 00(2004).
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The sole source of supply of the apparatus known to the committee at this time is B. F. Perkins, 939 Chicopee St., Chicopee, MA 01013-2797, [phone]. If you
are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the 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 (2008)
FIG. 1 Mullen Tester, Model A
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 in
contact with the specimen and the rubber diaphragm shall be rounded to a radius of not over 0.025 in. (0.64 mm) to prevent any
cutting action. During the test, the circular edges of the openings in the two clamping plates shall be substantially concentric with
no overlapping of any point.
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, before
the diaphragm is stretched by pressure underneath it, the center of its upper surface is below the plane of the clamping surface.
5.5 Dial Gage, as shown in Fig. 2, to measure the extension of the leather specimen and mounted on the machine through screw
shaft or on side of clamps on platform. This gage shall be calibrated to read directly to the nearest 0.001 in. (0.03 mm). It shall
be equipped with a flat anvil and a presser foot.
5.6 Bourdon Tube—The apparatus shall be equipped with a Bourdon tube, maximum-reading-type, pressure gage graduated in
pounds-forcepersquareinchandaccuratethroughouttheentirerangeofitsscaletowithinavalueof1 %ofitsmaximumcapacity.
The capacity of the gage shall be such that the individual readings will be not less than 25 % nor more than 75 % of the total
capacity of the gage.
5.7 Pressure Control—The machine shall be equipped with means of applying controlled increasing hydraulic pressure to the
underside of the diaphragm until the specimen cracks. This pressure shall be generated by a piston forcing a liquor (usually
glycerin) into the pressure chamber of the apparatus. For machines shown in Fig. 1 where the cracking pressure is the only
measurement, the pressure will be generated by pumping liquid at a rate of 170 6 10 mL/min or by turning a handwheel at
FIG. 2 Mullen Tester with Dial Gage
D2210–00 (2008)
approximately 30 r/min. For machines shown in Fig. 2 where cracking pressure and extension are measured, the pressure will be
generated by pumping liquid at a rate of 15 6 2 mL/min or by turning a handwheel at approximately 3 r/min.
5.8 Thickness Gage—A dead-weight type of thickness gage as described in Test Method D 1813.
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 D 1610.
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 rubber diaphragm of the testing machine.
8.3 Clamp the specimen securely in the apparatus in such a manner that the leather will not be damaged.
8.4 Rest the presser foot of the extension gage on the flat surface of the specimen and set the gage at zero.
8.5 Apply pressure to the specimen until the specimen cracks.
8.6 At the moment the first crack appears in the specimen stop the machine, note the applied pressure from the gage, and record
the value as the cracking strength of the specimen.
9. Report
9.1 The report shall include the following:
9.1.1 Cracking pressure to the nearest 5 psi (35 kPa) for each specimen or averaged and reported as the average of the test unit,
9.1.2 Extension of the leather to the nearest 0.001 in. (0.03 mm), converted to percentage (see Annex A1) and reported as
percentage stretch, and
9.1.3 Thickness to the nearest 0.001 in. (0.03 mm) reported for each specimen or averaged and reported as the thickness of the
sample.
9.1.4 Speed the liquid was pumped to build pressure to the nearest 10 % (see 5.7).
10. Precision and Bias
10.1 The following criteria may be used to judge the acceptability of the results if at least 15 units have been tested:
10.1.1 One Operator, Duplicate Specimens, Same Skin —Results by the same operator in duplicate adjacent specimens in a skin
taken from the official sampling position should not be considered suspect unless the coefficient of variation exceeds:
D2210–00 (2008)
Extension at Grain
Leathers Cracking Pressure, psi Crack, %
Shoe upper 26 13
Upholstery 17 14
A
Calfskin 16 22
Glove 11 20
_____________
A
3 6 1 oz, 0.0468 6 0.0156 in. (1.189 6 0.396 mm).
10.1.2 Two Laboratories, Duplicate Specimens, Same Skin —Results for the same group of light leathers listed in 10.1.1
submitted by each of two laboratories on duplicate adjacent specimens in a skin taken from the official sampling posit
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:D2210–93 (Reapproved 1997) Designation:D2210–00(Reapproved 2008)
Standard Test Method for
Grain Crack and Extension of Leather by the Mullen Test
This standard is issued under the fixed designation D 2210; 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
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 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.
2. Referenced Documents
2.1 ASTM Standards:
D 1610 Practice for Conditioning Leather and Leather Products for Testing
D 1813 Test Method for Measuring Thickness of Leather Test Specimens
3. Terminology
3.1 Definitions:
3.1.1 extension—the amount of stretch of leather over the diaphragm under pressure.
3.1.2 grain cracking—the appearance of cracks on the surface of the leather as the leather is extended over a diaphragm under
pressure to form a sphere.
4. 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.
5. Apparatus
5.1 Testing Machine, as shown in Fig. 1. The machine shall be hand- or power-driven. The machine shall hold the specimen
firmly, without slippage, between two annular, plane, unpolished (matte) surfaces that may have fine, spiral tool marks not over
0.010 in. (0.25 mm) in depth.
5.2 Upper Clamping Surface—The upper clamping surface (clamping ring) shall have a circular opening 1.240 6 0.010 in.
(31.50 6 0.25 mm) in diameter and shall be connected to the clamping mechanism through a swivel joint to ensure an even
clamping pressure.
5.3 Lower Clamping Surface—The lower clamping surface (diaphragm plate) shall be 0.219 6 0.003 in. (5.56 6 0.08 mm)
This test method is under the jurisdiction of ASTM Committee D-31D31 on Leather and is the direct responsibility of Subcommittee D31.03 on Footwear. This test
method was developed in cooperation with the American Leather Chemists Assn. (Standard Method E 58 – 1965).
Current edition approved July 15, 1993.Sept. 1, 2008. Published September 1993.December 2008. Originally published approved in 1963 as D 2210 – 63T. Last previous
edition D2210–89´ . approved in 2004 as D 2210 – 00(2004).
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
, Vol 15.04.volume information, refer to the standard’s Document Summary page on the ASTM website.
The sole source of supply of the apparatus known to the committee at this time is B. F. Perkins, 939 Chicopee St., Chicopee, MA 01013-2797, [phone]. If you
are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful consideration at a meeting of the 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 (2008)
FIG. 1 Mullen Tester, Model A
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 in
contact with the specimen and the rubber diaphragm shall be rounded to a radius of not over 0.025 in. (0.64 mm) to prevent any
cutting action. During the test, the circular edges of the openings in the two clamping plates shall be substantially concentric with
no overlapping of any point.
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, before
the diaphragm is stretched by pressure underneath it, the center of its upper surface is below the plane of the clamping surface.
5.5 Dial Gage, as shown in Fig. 2, to measure the extension of the leather specimen and mounted on the machine through screw
shaft or on side of clamps on platform. This gage shall be calibrated to read directly to the nearest 0.001 in. (0.03 mm). It shall
be equipped with a flat anvil and a presser foot.
5.6 Bourdon Tube—The apparatus shall be equipped with a Bourdon tube, maximum-reading-type, pressure gage graduated in
pounds-forcepersquareinchandaccuratethroughouttheentirerangeofitsscaletowithinavalueof1 %ofitsmaximumcapacity.
The capacity of the gage shall be such that the individual readings will be not less than 25 % nor more than 75 % of the total
capacity of the gage.
5.7 Pressure Control—The machine shall be equipped with means of applying controlled increasing hydraulic pressure to the
underside of the diaphragm until the specimen cracks. This pressure shall be generated by a piston forcing a liquor (usually
glycerin) into the pressure chamber of the apparatus. For machines shown in Fig. 1 where the cracking pressure is the only
measurement, the pressure will be generated by pumping liquid at a rate of 170 6 10 mL/min or by turning a handwheel at
FIG. 2 Mullen Tester with Dial Gage
D2210–00 (2008)
approximately 30 r/min. For machines shown in Fig. 2 where cracking pressure and extension are measured, the pressure will be
generated by pumping liquid at a rate of 15 6 2 mL/min or by turning a handwheel at approximately 3 r/min.
5.8 Thickness Gage—A dead-weight type of thickness gage as described in Test Method D 1813.
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 D 1610.
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 rubber diaphragm of the testing machine.
8.3 Clamp the specimen securely in the apparatus in such a manner that the leather will not be damaged.
8.4 Rest the presser foot of the extension gage on the flat surface of the specimen and set the gage at zero.
8.5 Apply pressure to the specimen until the specimen cracks.
8.6 At the moment the first crack appears in the specimen stop the machine, note the applied pressure from the gage, and record
the value as the cracking strength of the specimen.
9. Report
9.1 The report shall include the following:
9.1.1 Cracking pressure to the nearest 5 psi (35 kPa) for each specimen or averaged and reported as the average of the test unit,
9.1.2 Extension of the leather to the nearest 0.001 in. (0.03 mm), converted to percentage (see Annex A1) and reported as
percentage stretch, and
9.1.3 Thickness to the nearest 0.001 in. (0.03 mm) reported for each specimen or averaged and reported as the thickness of the
sample.
9.1.4 Speed the liquid was pumped to build pressure to the nearest 10 % (see 5.7).
10. Precision and Bias
10.1 The following criteria may be used to judge the acceptability of the results if at least 15 units have been tested:
10.1.1 One Operator, Duplicate Specimens, Same Skin —Results by the same operator in duplicate adjacent specimens in a skin
taken from the official sampling position should not be considered suspect unless the coefficient of variation exceeds:
D2210–00 (2008)
Extension at Grain
Leathers Cracking Pressure, psi Crack, %
Shoe upper 26 13
Upholstery 17 14
A
Calfskin 16 22
Glove 11 20
_____________
A
3 6 1 oz, 0.0468 6 0.0156 in. (1.189 6 0.396 mm).
10.1.2 Two Laboratories, Duplicate Specimens, Same Skin —Results for the same group of light leathers listed in 10.1.1
submitted by each of two laboratories on duplicate adjacent specimens in a skin taken from the
...