ASTM D6686-01(2019)

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: D6686 − 01 (Reapproved 2019)
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 4. Summary of Test Method
1.1 This test method is an accelerated procedure to deter-
4.1 This test method utilizes a condensation test chamber to
mine the effectiveness of latex coatings at preventing the
determine the tannin stain resistance of latex paints. The test
migration of tannin stains from wood substrates.
paints are applied to substrates that contain tannin extractives
and are placed on or in the test chamber. CIELAB L* and b*
1.2 The values in SI units are to be regarded as the standard.
valuesaswellassubjectiveratingsarerecordedafterexposure.
The values in parentheses are for information only.
1.3 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
5.1 Tannins and other chromophoric extractives are natu-
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- rally occurring materials in wood and wood-based substrates.
Tannins are prevalent to a high degree in cedar, redwood, oak,
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor- and to a lesser degree in white and yellow pine. Tannins are
alsopresentinvaryingamountsinwoodcompositionproducts.
dance with internationally recognized principles on standard-
These extractives are solubilized and darkened in color by
ization established in the Decision on Principles for the
aqueous coatings, resulting in unsightly yellow or brown
Development of International Standards, Guides and Recom-
discolorations. This test method is designed to show the
mendations issued by the World Trade Organization Technical
relative ability of paints to prevent tannin bleed-through.
Barriers to Trade (TBT) Committee.
Typically, cedar or redwood panels are used for this test.
2. Referenced Documents
6. Apparatus
2.1 ASTM Standards:
D1475 Test Method for Density of Liquid Coatings, Inks,
6.1 Test Chamber, as described in Practice D4585.
and Related Products
6.2 Test Substrate, 15.2 by 121.9 cm (6 by 48 in.) substrate
D4585 Practice for Testing Water Resistance of Coatings
or of a size agreed upon by the purchaser and seller of the
Using Controlled Condensation
coating being tested.
D5068 Practice for Preparation of Paint Brushes for Evalu-
6.3 Paint Brush, nylon/polyester brush of good quality.
ation
6.4 Spectrophotometer.
3. Terminology
6.5 Electronic Balance.
3.1 Definitions:
6.6 Conditioned Room,at18to29.5 °C(65to85 °F)and40
3.1.1 tannin stain resistance, n—the ability of a coating to
prevent the migration of tannins or other wood-based chromo- to 60 % relative humidity.
spheres to the surface of a film.
7. Reagents and Materials
7.1 Wood Panels—Such as cedar, redwood, oak, white pine,
This test method is under the jurisdiction of ASTM Committee D01 on Paint
yellow pine, or other substrate as agreed upon between the
and Related Coatings, Materials, andApplications and is the direct responsibility of
purchaser and the seller of the coating being tested.
Subcommittee D01.42 on Architectural Coatings.
Current edition approved April 1, 2019. Published April 2019. Originally
7.2 Control Paint—An agreed-upon paint of known tannin
approved in 2001. Last previous edition approved in 2013 as D6686 – 01 (2013).
stain resistance.
DOI: 10.1520/D6686-01R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
7.3 Test Paints—Since there are no standard panels,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
photographs, or paints for this test method, an agreed-upon
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. control paint (7.2) should be included as one of the test paints.
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D6686 − 01 (2019)
8. Procedure place backprimed panels fully inside the chamber if agreed
uponbetweenthepurchaserandseller.Allpanelsshouldberun
8.1 Choose a substrate with a consistent grain pattern.
similarly. If the panels are placed on the chamber, fill all spaces
Patterns vary greatly from panel to panel, so try to select a
in the specimen rack with test boards or blanks. Close all
board that has consistent wood grain across the length of the
cracks between boards to prevent water vapor loss and tem-
substrate. Results may vary from panel to panel because of
perature variation. Larger cracks may be closed with tape or
different growth rates, grain angles, colors, and species of
metal strips. If the panels are placed inside the chamber, make
wood. If necessary, panels may be sanded to remove raised
sure panels are placed at an angle to avoid water spotting and
grain. Substrates with areas of rough spots should be avoided,
run off onto the test areas
...