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).)  
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 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. Specific hazard statements are given in Section 7.

General Information

Status
Historical
Publication Date
30-Nov-2010
Current Stage
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ASTM D2370-98(2010) - 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 (Reapproved2010)
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, n—the increase in specimen length from
the point of initial load application to the point of film rupture
1.1 This test method covers the determination of the
in a tension test.
elongation, tensile strength, and stiffness (modulus of elastic-
3.1.2 gage length, n—the initial length of the test specimen
ity) of 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), n—the load per unit
as standard. The values given in parentheses are mathematical
arearequiredtoelongatethefilm1 %fromthefirstpointinthe
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, n—the curve resulting from a plot
1.3 This standard does not purport to address all of the
of tensile load against the distance of jaw separation (elonga-
safety concerns, if any, associated with its use. It is the
tion of specimen).
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3.1.5 tensile strength (nominal), n—the load per original
bility of regulatory limitations prior to use. Specific hazard
unit area at which a specimen fails or yields in a tension (pull)
statements are given in Section 7.
test.
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
4.1 Free unsupported films of the materials to be tested are
D823 Practices for Producing Films of Uniform Thickness
prepared.Thetensilepropertiesofthefreefilmsaredetermined
of Paint, Varnish, and Related Products on Test Panels
by means of a tensile testing apparatus.
D882 Test Method for Tensile Properties of Thin Plastic
Sheeting
5. Significance and Use
D1005 Test Method for Measurement of Dry-Film Thick-
5.1 Tensile properties determined by this method are of
ness of Organic Coatings Using Micrometers
value in studying the behavior of coatings subjected to envi-
D3980 Practice for Interlaboratory Testing of Paint and
3 ronmental stresses, such as those produced by aging and
Related Materials (Withdrawn 1998)
weathering. (See Refs. (1-10).)
D4708 Practice for Preparation of Uniform Free Films of
5.2 Tensile properties may vary with specimen thickness,
Organic Coatings
method of preparation, gage length, rate of load application,
3. Terminology tensile tester response, and type of grips used. Consequently,
where precise comparative results are desired, these factors
3.1 Definitions of Terms Specific to This Standard:
must be carefully controlled.
1 6. Apparatus
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
6.1 Equipment for applying films of uniform thickness as
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
described in Practices D823.
Current edition approved Dec. 1, 2010. Published December 2010. Originally
´1
approved in 1965. Last previous edition approved in 2002 as D2370 – 98 (2002) .
6.2 Micrometer Film Thickness Gage as described in Test
DOI: 10.1520/D2370-98R10.
2 Method D1005.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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.
3 4
The last approved version of this historical standard is referenced on Boldface numbers in parentheses refer to the list of references at the end of this
www.astm.org. standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2370 − 98 (2010)
6.3 Tensile Testeroftheconstantrateofjawseparationtype, 73.5 6 3.5°F (23 6 2°C) and 50 % relative humidity and test
equipped with load cells having capacities of 0.2 to 4.4 lb (100 in the same environment.
to 2000 g), and equipped with an indicating device such as an
electronic constant speed chart recorder, a digital device that 11. Procedure
displays numerical values, or a printer that records the numeri-
11.1 Select a mutually agreed upon gage length in the range
cal values.
of 1 to 5 in. (25 to 125 mm).
6.4 Precision Specimen Cutter having a double blade with a
11.2 Prepare 10 test specimens for each material to be
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
NOTE 1—Other substrates that may be suitable are 10-mil (250-µm)
testing machine, taking care to align the long axis of the
thick polyethylene (7), photographic paper (8), polished steel (9), and
specimen with an imaginary line joining the points of attach-
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
8. Test Specimens
testing the types of materials to be evaluated. For relatively brittle films,
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.
9.1 Balance, zero, and calibrate the load weighing and
11.5.3 If stiffness is desired, determine the tensile pull in
recording system of the tensile tester in accordance with
pounds (kg) to elongat
...

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