ASTM D6900-10(2015)

Standard Test Method for Wet Adhesion of Latex Paints to a Gloss Alkyd Enamel Substrate

SIGNIFICANCE AND USE
5.1 After application to either interior or exterior surfaces, latex paints may be subjected to conditions of high humidity, condensation, or precipitation. This may sometimes lead to a loss of adhesion to the substrate over which they have been applied. This method is a quantitative measure of the adhesion of latex paints to glossy substrates under such conditions.
SCOPE
1.1 This method covers a procedure for measuring by scrubbing the adhesion of latex paints to glossy alkyd enamel substrates after exposure to wet conditions.  
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.

General Information

• Status: Historical
• Publication Date: 31-May-2015
• ICS: 87.040 - Paints and varnishes
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.42 - Architectural Coatings

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6900 − 10 (Reapproved 2015)
Standard Test Method for
Wet Adhesion of Latex Paints to a Gloss Alkyd Enamel
Substrate
This standard is issued under the fixed designation D6900; 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 method covers a procedure for measuring by
4.1 Test paints, with optional control paint, are drawn down
scrubbing the adhesion of latex paints to glossy alkyd enamel
using a 7-mil clearance Dow applicator (~11 m /L) across a
substrates after exposure to wet conditions.
cured alkyd gloss enamel previously drawn down on a black or
white plastic panel.
1.2 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information
4.2 The drawdown films are allowed to dry under standard-
only.
izedconditions.Then,eighteencutsaremadetoforma6by10
1.3 This standard does not purport to address all of the
cut block, creating sixty 6.4 mm (0.25 in) squares, in the center
safety concerns, if any, associated with its use. It is the
of each film with a razor blade.
responsibility of the user of this standard to establish appro-
4.3 The panels are then soaked for 30 min in ambient tap
priate safety and health practices and determine the applica-
water. The panel is mounted in a washability tester and 20 mL
bility of regulatory limitations prior to use.
of water are applied. The panel is then scrubbed for up to 500
cycles or until all of the squares within each block are
2. Referenced Documents
completely removed.
2.1 ASTM Standards:
D523 Test Method for Specular Gloss
5. Significance and Use
D714 Test Method for Evaluating Degree of Blistering of
5.1 After application to either interior or exterior surfaces,
Paints
D2486 Test Methods for Scrub Resistance of Wall Paints latex paints may be subjected to conditions of high humidity,
condensation, or precipitation. This may sometimes lead to a
D3924 Specification for Environment for Conditioning and
Testing Paint, Varnish, Lacquer, and Related Materials loss of adhesion to the substrate over which they have been
applied. This method is a quantitative measure of the adhesion
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method of latex paints to glossy substrates under such conditions.
E177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods 6. Apparatus
6.1 Constanttemperature/humidityroominaccordancewith
3. Terminology
Specification D3924 [23 6 2°C (73.5 6 3.5°F) and 50 65%
3.1 Definitions of Terms Specific to This Standard:
relative humidity].
3.1.1 wet adhesion, n—the ability of a coating to resist
6.2 Drawdown Plate.
removal by scrubbing from the surface beneath it after expo-
sure to wet conditions and abrasion.
6.3 Straight Line Washability Tester and Accessories, per
Test Methods D2486.
6.4 Nylon Bristle Brush and Accessories (nominal weight
This test method is under the jurisdiction of ASTM Committee D01 on Paint
455 g), having nylon brush bristles in 5/4 pattern extending 19
and Related Coatings, Materials, andApplications and is the direct responsibility of
mm ( ⁄4 in.) from block (as per Test Methods D2486).
Subcommittee D01.42 on Architectural Coatings.
Current edition approved June 1, 2015. Published June 2015. Originally
6.5 Dow FilmApplicator,having7-mil(0.18-mm)clearance
approved in 2003. Last previous edition approved in 2010 as D6900 – 10.
DOI:10.1520/D6900-10R15.
by 5.2-in. (132-mm) width. applicator blade.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
6.6 Single-edge Razor Blade, in safety holder.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 6.7 Metal Straight Edge, (or appropriate guide).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6900 − 10 (2015)
NOTE 2—Since humidity and temperature both markedly influence the
rateatwhichpaintdries,aconstanttemperature/humidityroomisstrongly
recommended in order to achieve reproducible results using this method.
8.2.3 Condition, break in and rinse the scrub brush as
specified in Test Methods D2486.
8.2.4 Using a metal straightedge or suitable guide, make
eighteen razor blade cuts, spaced 6.4 mm (0.25 in.) apart
forminga6by10 array with a razor blade in the center of each
paint (See Fig. 1). Each cut should be made in one steady
motion with sufficient pressure to cut, but not tear the latex
paint film. (Warning—Avoid cutting completely through the
alkyd enamel into the plastic substrate.)
8.2.5 Submerge each panel face-up for 30 min in a flat
FIG. 1 Illustration
container of ambient tap water, being careful not to bend the
substrate.
8.2.6 Removethepanelfromthewaterandquicklyexamine
7. Reagents and Materials
the panel for blistering, per Test Method D714 (optional).
7.1 A ready-mix deep-tint alkyd gloss enamel with a 60°
Immediatelysecurethepanelinthewashabilitytesterusingthe
gloss of at least 65 as measured in accordance with Test
gasketed frame accessory, ensuring that the array is in the path
Method D523 (or alkyd as agreed upon by the purchaser and
of the brush. Place 20 mLof water in the path of the brush and
supplier).
start the machine.
8.2.7 Observe each test paint to determine its point of
7.2 Plastic test panels as used in Test Methods D2486.
adhesive failure. Record the number of cycles when 100 %
8. Procedure
adhesive failure occurs or the percent adhesive failure at 500
cycles. If the test paint is not removed within 500 cycles, the
8.1 Preparation of the Alkyd Substrate Panels—Attach the
test is terminated. Since the array is larger than the brush for
plastic panel to the drawdown plate and drawdown the alkyd
ease of placement, only rate the path of the brush.
gloss enamel lengthwise using a 7-mil clearance Dow appli-
cator. The time for application should be fairly slow—3 to 4 s
9. Report
from end to end. The drawdown must be free of ridges,
holidays, specks, or other imperfections, which may affect 9.1 Record any blistering, perTest Method D714 (optional).
adhesion.
9.2 The number of cycles for 100 % adhesive failure or
8.1.1 Allow the alkyd gloss enamel to air-dry in a horizontal
percent adhesive failure after 500 cycles.
position.Allowtocuretypicallyforaminimumofthreeweeks.
9.3 The wet film thickness of the gloss alkyd enamel and
Panels are to be used between three to six weeks from the date
latex test paints if different than those specified in this test
of preparation. Wet adhesion with some late
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6900 − 10 D6900 − 10 (Reapproved 2015)
Standard Test Method for
Wet Adhesion of Latex Paints to a Gloss Alkyd Enamel
Substrate
This standard is issued under the fixed designation D6900; 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
1.1 This method covers a procedure for measuring by scrubbing the adhesion of latex paints to glossy alkyd enamel substrates
after exposure to wet conditions.
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.
2. Referenced Documents
2.1 ASTM Standards:
D523 Test Method for Specular Gloss
D714 Test Method for Evaluating Degree of Blistering of Paints
D2486 Test Methods for Scrub Resistance of Wall Paints
D3924 Specification for Environment for Conditioning and Testing Paint, Varnish, Lacquer, and Related Materials
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 wet adhesion, n—the ability of a coating to resist removal by scrubbing from the surface beneath it after exposure to wet
conditions and abrasion.
4. Summary of Test Method
4.1 Test paints, with optional control paint, are drawn down using a 7-mil clearance Dow applicator (~11 m /L) across a cured
alkyd gloss enamel previously drawn down on a black or white plastic panel.
4.2 The drawdown films are allowed to dry under standardized conditions. Then, eighteen cuts are made to form a 6 by 10 cut
block, creating sixty 6.4 mm (0.25 in) squares, in the center of each film with a razor blade.
4.3 The panels are then soaked for 30 min in ambient tap water. The panel is mounted in a washability tester and 20 mL of water
are applied. The panel is then scrubbed for up to 500 cycles or until all of the squares within each block are completely removed.
5. Significance and Use
5.1 After application to either interior or exterior surfaces, latex paints may be subjected to conditions of high humidity,
condensation, or precipitation. This may sometimes lead to a loss of adhesion to the substrate over which they have been applied.
This method is a quantitative measure of the adhesion of latex paints to glossy substrates under such conditions.
This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.42 on Architectural Coatings.
Current edition approved Feb. 1, 2010June 1, 2015. Published March 2010June 2015. Originally approved in 2003. Last previous edition approved in 20032010 as
D6900 – 03.D6900 – 10. DOI:10.1520/D6900-10.DOI:10.1520/D6900-10R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6900 − 10 (2015)
6. Apparatus
6.1 Constant temperature/humidity room in accordance with Specification D3924 [23 6 2°C (73.5 6 3.5°F) and 50 6 5 %
relative humidity].
6.2 Drawdown Plate.
6.3 Straight Line Washability Tester and Accessories, per Test Methods D2486.
6.4 Nylon Bristle Brush and Accessories (nominal weight 455 g), having nylon brush bristles in 5/4 pattern extending 19 mm
( ⁄4 in.) from block (as per Test Methods D2486).
6.5 Dow Film Applicator, having 7-mil (0.18-mm) clearance by 5.2-in. (132-mm) width. applicator blade.
6.6 Single-edge Razor Blade, in safety holder.
6.7 Metal Straight Edge, (or appropriate guide).
7. Reagents and Materials
7.1 A ready-mix deep-tint alkyd gloss enamel with a 60° gloss of at least 65 as measured in accordance with Test Method D523
(or alkyd as agreed upon by the purchaser and supplier).
7.2 Plastic test panels as used in Test Methods D2486.
8. Procedure
8.1 Preparation of the Alkyd Substrate Panels—Attach the plastic panel to the drawdown plate and drawdown the alkyd gloss
enamel lengthwise using a 7-mil clearance Dow applicator. The time for application should be fairly slow—3 to 4 s from end to
end. The drawdown must be free of ridges, holidays, specks, or other imperfections, which may affect adhesion.
8.1.1 Allow the alkyd gloss enamel to air-dry in a horizontal position. Allow to cure typically for a minimum of three weeks.
Panels are to be used between three to six weeks from the date of preparation. Wet adhesion with some latex paints may be
dramatically reduced if the alkyd is allowed to cure for more than six weeks.
8.2 Application and Evaluation of Test Paints:
8.2.1 Attach the cured alkyd enamel-coated plastic panel to the drawdown plate and simultaneously drawdown test paint and
an optional control paint side-by-side using the 7-mil clearance Dow applicator. The time for application should be fairly slow—1
to 2 s from edge to edge. Each drawdown is made perpendicular to the length of the panel and positioned so that the drawdowns
are contiguous (See Fig. 1).
NOTE 1—Typically a control paint of known wet adhesion is recommended for use in the method to limit the variability of results from test to test.
8.2.2 Condition the panels for one week in the constant temperature/humidity room as specified in Specification D3924 or under
other conditions agreed upon by buyer and seller. Shorter conditioning times may be used if more stringent measures of wet
adhesion are needed, as in the case of determining a coating’s “early” wet adhesion.
NOTE 2—Since humidity and temperature both markedly influence the rate at which paint dries, a constant temperature/humidity room is strongly
recommended in order to achieve reproducible results using this method.
8.2.3 Condition, break in and rinse the scrub brush as specified in Test Methods D2486.
This test method was qualified by a round robin using Leneta P-121-10N dull black plastic panels 6 ⁄2 by 17 in. by 10 mils (165 by 432 by 0.25 mm) in size, obtainable
from the Leneta Co., 15 Whitney Rd, Mahwah, NJ 07430.
FIG. 1 Illustration
D6900 − 10 (20
...