ASTM D2967-07(2017)
(Test Method)Standard Test Method for Corner Coverage of Powder Coatings
Standard Test Method for Corner Coverage of Powder Coatings
SIGNIFICANCE AND USE
4.1 This test method measures the degree to which different coating powder materials cover sharp corners. Corner coverage is influenced by face thickness, thixotropy, melt viscosity, surface tension, cure rate, and temperature of application and curing.
SCOPE
1.1 This test method covers the determination of the ratio of corner thickness (see 3.1.3) to face thickness (see 3.1.4) of powder coatings applied to a specific face thickness by dipping preheated square bars into aerated powder and curing the coating using predetermined conditions.
Note 1: The property of corner coverage has also been referred to as “edge coverage,” though the latter is not recommended. There are widespread misunderstandings and expectations relative to the term “edge coverage.” This test is performed on a steel bar having square corners and the results do not necessarily relate to edges that are sharper, that is, burrs. A coating that has measurable corner coverage may still not protect sharper edges from corrosion or provide the electrical insulation needed in some applications.
1.2 The values stated in SI 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.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D2967 − 07 (Reapproved 2017)
Standard Test Method for
Corner Coverage of Powder Coatings
This standard is issued under the fixed designation D2967; 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 3. Terminology
1.1 This test method covers the determination of the ratio of 3.1 Definitions:
3.1.1 coating powders, n—finely divided particles of resin,
corner thickness (see 3.1.3) to face thickness (see 3.1.4)of
either thermoplastic or thermosetting, generally incorporating
powder coatings applied to a specific face thickness by dipping
pigments, fillers, and additives and remaining finely divided
preheated square bars into aerated powder and curing the
during storage under suitable conditions, which, after fusing
coating using predetermined conditions.
and possibly curing, give a continuous film.
NOTE 1—The property of corner coverage has also been referred to as
3.1.1.1 Discussion—The coating powder may contain
“edge coverage,” though the latter is not recommended. There are
fillers, colorants, curing agents, etc., consistent with producing
widespread misunderstandings and expectations relative to the term “edge
thedesiredcoatings.Thepowderisappliedbyvariousmethods
coverage.” This test is performed on a steel bar having square corners and
the results do not necessarily relate to edges that are sharper, that is, burrs.
such as spraying, sprinkling, or dipping. Usually hot parts are
A coating that has measurable corner coverage may still not protect
used. Heat causes the powder to melt and flow into a dense
sharper edges from corrosion or provide the electrical insulation needed in
coating.
some applications.
3.1.2 corner coverage, n—of powder coating, the ratio of
1.2 The values stated in SI units are to be regarded as the
the corner thickness to the face thickness of the fused coating
standard. The values given in parentheses are for information
expressed in percent.
only.
3.1.3 corner thickness, n—of powder coating, the average
1.3 This standard does not purport to address all of the
thickness of the coating on sharp 90° corners of steel bars
safety concerns, if any, associated with its use. It is the
measured at 45° to the flat surfaces.
responsibility of the user of this standard to establish appro-
3.1.4 face thickness, n—of powder coating, the average
priate safety and health practices and determine the applica-
thickness of the coating on flat surfaces of steel bars measured
bility of regulatory limitations prior to use.
perpendicular to the surfaces.
1.4 This international standard was developed in accor-
3.1.5 powder coatings, n—coatings which are protective or
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the decorative, or both, formed by the application of a coating
powder to a substrate and fused in a continuous film by the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical application of heat or radiant energy.
Barriers to Trade (TBT) Committee.
4. Significance and Use
4.1 This test method measures the degree to which different
2. Referenced Documents
coating powder materials cover sharp corners. Corner coverage
2.1 ASTM Standards:
is influenced by face thickness, thixotropy, melt viscosity,
D374/D374M Test Methods for Thickness of Solid Electri-
surface tension, cure rate, and temperature of application and
cal Insulation
curing.
5. Apparatus
This test method is under the jurisdiction of ASTM Committee D01 on Paint
5.1 Aerated Bed—Suitable for providing a uniformly sus-
and Related Coatings, Materials, andApplications and is the direct responsibility of
pended dense phase of free–moving powder. Fig. 1 shows a
Subcommittee D01.51 on Powder Coatings.
schematic of an aerated bed used for suspending the coating
Current edition approved June 1, 2017. Published June 2017. Originally
powder.The equipment consists of an open top chamber which
approved in 1971. Last previous edition approved in 2013 as D2967 – 07 (2013).
DOI: 10.1520/D2967-07R17.
has a porous plate for a false bottom. Air is introduced under
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the plate at a low pressure so that it filters through the porous
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
plate and uniformly suspends the particles contained in the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. chamber.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2967 − 07 (2017)
removalincludetheuseofstrippingsolutions,heat,andcareful
scraping with a sharp blade, or combinations thereof.
6. Sampling
6.1 The powder sample shall be from one lot and be
representative of the lot.
7. Test Specimens
7.1 The test specimens shall be the steel ba
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.