ASTM D5178-98(2008)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D5178 − 98 (Reapproved2008)
Standard Test Method for
Mar Resistance of Organic Coatings
This standard is issued under the fixed designation D5178; 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.
1. Scope D2691 Method for Microscopical Measurement of Dry Film
Thickness of Coatings on Wood Products (Withdrawn
1.1 This test method covers the determination of the mar
1992)
resistance on smooth, flat surfaces. Results are expressed in
terms of force-to-mar films of organic coatings such as paint,
3. Terminology
varnish, and lacquer when applied to smooth, flat planar panel
3.1 Definitions:
surfaces.
3.1.1 mar resistance, n—the ability of a coating to resist
1.2 The values stated in inch-pound units are to be regarded
damage caused by light abrasion. As just defined, it is a
as standard. The values given in parentheses are mathematical
resistance of the surface of the coating to permanent
conversions to SI units that are provided for information only
deformation, resulting from the application of a dynamic
and are not considered standard.
mechanical force.
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 Thematerialsundertestareappliedatuniformthickness
priate safety and health practices and determine the applica-
to flat panels of uniform surface texture. After drying/curing,
bility of regulatory limitations prior to use.
the mar resistance is determined by pushing the panels beneath
a rounded stylus or loop that is loaded in increasing amounts
2. Referenced Documents
until the coating is marred.
2.1 ASTM Standards:
5. Significance and Use
D609 Practice for Preparation of Cold-Rolled Steel Panels
5.1 In some situations, marring of coatings applied to
for Testing Paint, Varnish, Conversion Coatings, and
substrates under typical use conditions is unacceptable. This
Related Coating Products
test method has been found useful in differentiating the degree
D823 Practices for Producing Films of Uniform Thickness
of marring of coatings on substrates. It is most useful in
of Paint, Varnish, and Related Products on Test Panels
providing relative ratings for a series of coated panels exhib-
D1005 Test Method for Measurement of Dry-Film Thick-
iting significant differences in marring.
ness of Organic Coatings Using Micrometers
D1186 Test Methods for Nondestructive Measurement of
5.2 In a limited laboratory study, meaningful mar results
Dry Film Thickness of Nonmagnetic Coatings Applied to
were impossible when powder coatings were tested. The mar
a Ferrous Base (Withdrawn 2006)
marking, that is, scratches, became less perceptible with time.
D1400 Test Method for Nondestructive Measurement of Dry
Therefore, powder coatings may not be applicable coatings for
Film Thickness of Nonconductive Coatings Applied to a
this test method.
Nonferrous Metal Base (Withdrawn 2006)
6. Apparatus
6.1 Application Equipment, as described in Practices D823.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
6.2 Film-Thickness Measuring Apparatus, as described in
and Related Coatings, Materials, andApplications and is the direct responsibility of
Test Methods D1005, D1186, D1400,or D2691.
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
Current edition approved July 1, 2008. Published July 2008. Originally approved
6.3 Balanced Beam Scrape Adhesion and Mar Tester (Fig. 1
in 1991. Last previous edition approved in 2002 D5178 – 98 (2002). DOI: 10.1520/
and Fig. 2), consisting of a balanced beam to which is secured
D5178-98R08.
a platform for supporting weights, and a rod at an angle of 45°
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
that holds the scraping loop. The rod shall be set so that the
Standards volume information, refer to the standard’s Document Summary page on
scraping loop contacts test surfaces directly below the weights.
the ASTM website.
The loop shall be ⁄16-in. (1.6 mm) diameter rod, bent into a
The last approved version of this historical standard is referenced on
www.astm.org. “U” shape with an outside radius of 0.128 6 0.002 in. (3.25 6
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D5178 − 98 (2008)
same environment, or immediately on removal therefrom,
unless otherwise specified or agreed upon by the seller and the
purchaser. Test at least two replicate specimens of each
material.
9. Procedure
9.1 In preparation for using the apparatus, ensure that it is
reasonablylevelandplaceitsothattheweightholderistoward
the operator. This places the beam release on the operator’s
right and allows freedom to move the test specimen manually
under the weighted scraping element (loop). Insert the loop
FIG. 1 Balanced Beam Scrape Adhesion and Mar Tester
into the holder as far as it will go and tighten the clamping
screw. Adjust the main bearing
...