Standard Test Method for Tensile Properties of Organic Coatings

SIGNIFICANCE AND USE
Tensile properties determined by this method are of value in studying the behavior of coatings subjected to environmental stresses, such as those produced by aging and weathering. (See Refs. (1-10).)5  
Tensile properties may vary with specimen thickness, method of preparation, gage length, rate of load application, tensile tester response, and type of grips used. Consequently, where precise comparative results are desired, these factors must be carefully controlled.
SCOPE
1.1 This test method covers the determination of the elongation, tensile strength, and stiffness (modulus of elasticity) of organic coatings when tested as free films.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
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. Specific hazard statements are given in Section 7.

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Historical
Publication Date
09-Dec-1998
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ASTM D2370-98(2002) - Standard Test Method for Tensile Properties of Organic Coatings
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D2370–98(Reapproved2002)
Standard Test Method for
Tensile Properties of Organic Coatings
This standard is issued under the fixed designation D2370; 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 3.1.1 elongation—the increase in specimen length from the
point of initial load application to the point of film rupture in
1.1 This test method covers the determination of the elon-
a tension test.
gation, tensile strength, and stiffness (modulus of elasticity) of
3.1.2 gage length—the initial length of the test specimen
organic coatings when tested as free films.
between the jaws of the tensile tester.
1.2 The values stated in inch-pound units are to be regarded
3.1.3 stiffness (modulus of elasticity)—the load per unit area
as standard. The values given in parentheses are mathematical
required to elongate the film 1 % from the first point in the
conversions to SI units that are provided for information only
stress-strain curve where the slope becomes constant.
and are not considered standard.
3.1.4 stress-strain curve—the curve resulting from a plot of
1.3 This standard does not purport to address all of the
tensile load against the distance of jaw separation (elongation
safety concerns, if any, associated with its use. It is the
of specimen).
responsibility of the user of this standard to establish appro-
3.1.5 tensile strength (nominal)—the load per original unit
priate safety and health practices and determine the applica-
area at which a specimen fails or yields in a tension (pull) test.
bility of regulatory limitations prior to use. Specific hazard
statements are given in Section 7.
4. Summary of Test Method
2. Referenced Documents 4.1 Free unsupported films of the materials to be tested are
prepared.Thetensilepropertiesofthefreefilmsaredetermined
2.1 ASTM Standards:
by means of a tensile testing apparatus.
D823 Practices for Producing Films of Uniform Thickness
of Paint, Varnish, and Related Products on Test Panels
5. Significance and Use
D882 Test Method for Tensile Properties of Thin Plastic
5.1 Tensile properties determined by this method are of
Sheeting
value in studying the behavior of coatings subjected to envi-
D1005 Test Method for Measurement of Dry-Film Thick-
ronmental stresses, such as those produced by aging and
ness of Organic Coatings Using Micrometers
weathering. (See Refs. (1-10).)
D3980 Practice for Interlaboratory Testing of Paint and
3 5.2 Tensile properties may vary with specimen thickness,
Related Materials
method of preparation, gage length, rate of load application,
D4708 Practice for Preparation of Uniform Free Films of
tensile tester response, and type of grips used. Consequently,
Organic Coatings
where precise comparative results are desired, these factors
3. Terminology must be carefully controlled.
3.1 Definitions of Terms Specific to This Standard:
6. Apparatus
6.1 Equipment for applying films of uniform thickness as
described in Practices D823.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
6.2 Micrometer Film Thickness Gage as described in Test
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Method D1005.
Current edition approved Dec. 10, 1998. Published February 1999. Originally
6.3 Tensile Tester of the constant rate of jaw separation
approved in 1965. Last previous edition approved in 1998 as D2370 – 98. DOI:
10.1520/D2370-98R02. type, equipped with load cells having capacities of 0.2 to 4.4 lb
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
(100 to 2000 g), and equipped with an indicating device such
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. Boldface numbers in parentheses refer to the list of references at the end of this
Withdrawn. standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2370–98 (2002)
as an electronic constant speed chart recorder, a digital device 11. Procedure
that displays numerical values, or a printer that records the
11.1 Select a mutually agreed upon gage length in the range
numerical values.
of 1 to 5 in. (25 to 125 mm).
6.4 Precision Specimen Cutter having a double blade with
11.2 Prepare 10 test specimens for each material to be
a foot to hold the sample in place.
evaluated. These specimens should not exhibit any nicks or
6.5 Alternative Substrates on which test material can be
flaws.Measurethethicknessofeachspecimento 60.1mil(2.5
deposited.
µm) with a micrometer in accordance with Test Methods
6.5.1 Dental Tin Foil, preferably 1 mil (25 µm) thick.
D1005, taking five measurements within the gage length area.
6.5.2 Sheet of FEP (fluorinated ethylene-propylene), pref-
11.3 Set the jaw separation of the tensile tester at the gage
erably 2 mils (50 µm) thick, coated with a dry lubricant.
length selected. Place the test specimen in the grips of the
testing machine, taking care to align the long axis of the
NOTE 1—Other substrates that may be suitable are 10-mil (250-µm)
specimen with an imaginary line joining the points of attach-
thick polyethylene (7), photographic paper (8), polished steel (9), and
fluoropolymer coated metal panels. ment of the grips to the machine. Tighten the grips evenly and
firmly to the degree necessary to minimize slipping of the
7. Hazards
specimen during test.
7.1 Mercury—Mercury is a toxic metallic liquid. Its vapors
NOTE 2—Mounting is facilitated by the use of air activated jaws.
are extremely hazardous. Small amounts of spilled mercury
Line-type jaws will minimize slippage and breakage. The application of
can vaporize sufficiently at room temperature to exceed the
pressure-sensitive cloth to the ends of the film can improve jaw grip.
threshold limit values (TLV) of the vapor. Use with adequate
11.4 Selectamutuallyagreeduponrateofelongation(strain
ventilation (in a hood) and clean up spills immediately. Wear
rate) that is in the range of 5 to 100 %/min. Set the crosshead
gloves when handling mercury. Keep containers closed. Drop-
speed of the tensile tester to provide this rate for the gage
lets of mercury can be picked up by using a small glass pipet
length chosen.
connected to a suction flask with a rubber hose.
NOTE 3—A rate of elongation should be selected that is optimum for
testing the types of materials to be evaluated. For relatively brittle films,
8. Test Specimens
elongationratesof5to20 %aresuggested.Forrelativelyextensiblefilms,
8.1 The test specimens shall be free films having a width
elongation rates of 50 to 100 % are suggested. (Refer to Test Methods
thatisbetween ⁄2and1in.(13and25mm).Nospecimenshall D882 for relation of elongation rate to elongation at break).
vary by more than 62 % in width along its entire length. The
11.5 Elongate the test specimen until rupture of the film
length shall be at least 2 in. (50 mm) longer than the gage
occurs and evaluate the stress-strain curve as follows:
length selected for the test.
11.5.1 Determine the specimen elongation by measuring the
8.2 Prepare free films by one of the procedures described in
increase in jaw separation from the point of original load
Test Method D4708.
application to the point of rupture.
11.5.2 Measure the tensile pull in pounds (kg) required to
9. Calibration
rupture the film.
11.5.3 If stiffness is desired, determine the tensile pull in
9.1 Balance, zero, and calibrate the load weighing and
pounds (kg) to elongate the film 1 % from the first point in the
recording system of the tensile tester in accordance with
stress-strain curve where the slope becomes constant.
methods specified by the manufacturer.
11.6 Us
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