ASTM D6686-01(2013)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D6686 − 01 (Reapproved 2013)
Standard Test Method for
Evaluation of Tannin Stain Resistance of Coatings
This standard is issued under the fixed designation D6686; 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 5. Significance and Use
1.1 This test method is an accelerated procedure to deter- 5.1 Tannins and other chromophoric extractives are natu-
mine the effectiveness of latex coatings at preventing the rally occurring materials in wood and wood-based substrates.
migration of tannin stains from wood substrates. Tannins are prevalent to a high degree in cedar, redwood, oak
and to a lesser degree in white and yellow pine. Tannins are
1.2 The values in SI units are to be regarded as the standard.
alsopresentinvaryingamountsinwoodcompositionproducts.
The values in parenthesis are for information only.
These extractives are solubilized and darkened in color by
1.3 This standard does not purport to address all of the
aqueous coatings, resulting in unsightly yellow or brown
safety concerns, if any, associated with its use. It is the
discolorations. This test method is designed to show the
responsibility of the user of this standard to establish appro-
relative ability of paints to prevent tannin bleed-through.
priate safety and health practices and determine the applica-
Typically cedar or redwood panels are used for this test.
bility of regulatory limitations prior to use.
6. Apparatus
2. Referenced Documents
6.1 Test Chamber, as described in Practice D4585.
2.1 ASTM Standards:
6.2 Test Substrate, 15.2 by 121.9 cm (6 by 48 in.) substrate
D1475 Test Method For Density of Liquid Coatings, Inks,
or of a size agreed upon by the purchaser and seller of the
and Related Products
coating being tested.
D4585 Practice for Testing Water Resistance of Coatings
Using Controlled Condensation
6.3 Paint Brush, nylon/polyester brush of good quality.
D5068 Practice for Preparation of Paint Brushes for Evalu-
6.4 Spectrophotometer.
ation
6.5 Electronic Balance.
3. Terminology
6.6 Conditioned Room, at 18 to 29.5°C (65 to 85°F) and 40
to 60 % relative humidity.
3.1 Definitions:
3.1.1 tannin stain resistance, n—the ability of a coating to
7. Reagents and Materials
prevent the migration of tannins or other wood-based chromo-
spheres to the surface of a film.
7.1 Wood Panels—Such as cedar, redwood, oak, white pine,
yellow pine or other substrate as agreed upon between the
4. Summary of Test Method
purchaser and the seller of the coating being tested.
4.1 This test method utilizes a condensation test chamber to
7.2 Control Paint—An agreed-upon paint of known tannin
determine the tannin stain resistance of latex paints. The test
stain resistance.
paints are applied to substrates that contain tannin extractives
7.3 Test Paints—Since there are no standard panels,
and are placed on or in the test chamber. CIELAB L* and b*
photographs, or paints for this test method, an agreed-upon
valuesaswellassubjectiveratingsarerecordedafterexposure.
control paint (7.2) should be included as one of the test paints.
8. Procedure
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
8.1 Choose a substrate with a consistent grain pattern.
Subcommittee D01.42 on Architectural Coatings.
Patterns vary greatly from panel to panel, so try to select a
Current edition approved Feb. 1, 2013. Published February 2013. Originally
ε2
board that has consistent wood grain across the length of the
approved in 2001. Last previous edition approved in 2008 as D6686 – 01 (2008) .
DOI: 10.1520/D6686-01R13.
substrate. Results may vary from panel to panel because of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
different growth rates, grain angles, colors and species of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
wood. If necessary, panels may be sanded to remove raised
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. grain. Substrates with areas of rough spots should be avoided,
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D6686 − 01 (2013)
as they will bleed through more readily. Divide substrate into cracks between boards to prevent water vapor loss and tem-
strips at least 15.2 cm (6 in.) wide or as agreed upon between perature variation. Larger cracks may be closed with tape or
the purchaser and the seller and label the back of each test area metal strips. If the panels are placed inside the chamber, make
with paint designation. The control paint should be placed near sure panels are placed at an angle to avoid water spotting and
the middle of the panel. run off onto the test areas.
8.2 Prepare the cabinet as described in Practice D4585. 8.7 Adjust the thermostat to maintain the desired tempera-
ture of the saturated air and water vapor mixt
...