ASTM D5178-98

Designation: D 5178 – 98
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
1
Mar Resistance of Organic Coatings
This standard is issued under the fixed designation D 5178; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope resistance of the surface of the coating to permanent deforma-
tion, resulting from the application of a dynamic mechanical
1.1 This test method covers the determination of the mar
force.
resistance on smooth, flat surfaces. Results are expressed in
terms of force-to-mar films of organic coatings such as paint,
4. Summary of Test Method
varnish, and lacquer when applied to smooth, flat planar panel
4.1 The materials under test are applied at uniform thickness
surfaces.
to flat panels of uniform surface texture. After drying/curing,
1.2 The values stated in inch-pound units are to be regarded
the mar resistance is determined by pushing the panels beneath
as the standard. The values given in parentheses are for
a rounded stylus or loop that is loaded in increasing amounts
information only.
until the coating is marred.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 In some situations, marring of coatings applied to
priate safety and health practices and determine the applica-
substrates under typical use conditions is unacceptable. This
bility of regulatory limitations prior to use.
test method has been found useful in differentiating the degree
of marring of coatings on substrates. It is most useful in
2. Referenced Documents
providing relative ratings for a series of coated panels exhib-
2.1 ASTM Standards:
iting significant differences in marring.
D 609 Practice for Preparation of Cold-Rolled Steel Panels
5.2 In a limited laboratory study, meaningful mar results
for Testing Paint, Varnish, Conversion Coatings, and
2 were impossible when powder coatings were tested. The mar
Related Coating Products
marking, that is, scratches, became less perceptible with time.
D 823 Practices for Producing Films of Uniform Thickness
2 Therefore, powder coatings may not be applicable coatings for
of Paint, Varnish, and Related Products on Test Panels
this test method.
D 1005 Test Method for Measuring of Dry-Film Thickness
2
of Organic Coatings Using Micrometers
6. Apparatus
D 1186 Test Methods for Nondestructive Measurement of
6.1 Application Equipment, as described in Practices D 823.
Dry Film Thickness of Nonmagnetic Coatings Applied to
2 6.2 Film-Thickness Measuring Apparatus, as described in
a Ferrous Base
Test Methods D 1005, D 1186, D 1400, or D 2691.
D 1400 Test Methods for Nondestructive Measurement of
6.3 Balanced Beam Scrape Adhesion and Mar Tester (Fig.
Dry Film Thickness of Nonconductive Coatings Applied to
1 and Fig. 2), consisting of a balanced beam to which is
2
a Nonferrous Metal Base
secured a platform for supporting weights, and a rod at an
D 2691 Test Methods for Microscopical Measurement of
angle of 45° that holds the scraping loop. The rod shall be set
3
Dry Film Thickness of Coatings on Wood Products
so that the scraping loop contacts test surfaces directly below
1
the weights. The loop shall be ⁄16-in. (1.6 mm) diameter rod,
3. Terminology
bent into a “U” shape with an outside radius of 0.128 6 0.002
3.1 Definitions:
in. (3.25 6 0.05 mm) and hardened to Rockwell HRC 56 to 58,
3.1.1 mar resistance—the ability of a coating to resist
and shall be a smooth finish. The loop can be either chromium
damage caused by light abrasion. As just defined, it is a
plated, nickel plated, or heat treated polished steel as agreed
upon between the purchaser and the supplier. These testers are
1
This test method is under the jurisdiction of ASTM Committee D-1 on Paints adjustable to accommodate flat, metallic, and nonmetallic
and Related Coatings, Materials, and Applications and is the direct responsibility of
specimens to 0.5-in. (12-mm) thick and 4 to 16 in. (100 to 400
Subcommittee D01.23 on Physical Properties of Applied Paint Films.
1
mm) wide and long; the specimen should be at least ⁄2-in.
Current edition approved Feb. 10, 1998. Published September 1998. Originally
(12-mm) wide.
published as D 5178 – 91. Last previous edition D 5178 – 91.
2
Annual Book of ASTM Standards, Vol 06.01.
3
Discontinued; see 1992 Annual Book of ASTM Standards, Vol 06.02.
1

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D 5178
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 ele
...