ASTM D7488-11
(Test Method)Standard Test Method for Open Time of Latex Paints
Standard Test Method for Open Time of Latex Paints
SIGNIFICANCE AND USE
Latex paints dry very quickly which often causes difficulty in final appearance of painted areas, especially paints formulated below 100g/L VOC where lower amounts of solvents are in the formulated latex paint. This method is a means of determining the time available before a test paint cannot be worked into a previously painted area.
SCOPE
1.1 This test method covers a procedure to determine the length of time a latex paint remains “wet” or “open” enough to allow for brush-in and repair.
1.2 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.
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Designation: D7488 − 11
StandardTest Method for
1
Open Time of Latex Paints
This standard is issued under the fixed designation D7488; 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 temperature / humidity room (23 6 2°C (73.5 6 3.5°F)) / 50
65 %relativehumidity.Testpaintsareappliedtothecenterof
1.1 This test method covers a procedure to determine the
a sealed chart with a 76 microns (3 mil) wet film thickness. X
length of time a latex paint remains “wet” or “open” enough to
marks are made immediately. The number of X marks will
allow for brush-in and repair.
dependonhowmanycanfitononedrawdown(seeFig.1).The
1.2 This standard does not purport to address all of the
test paint is then applied in perpendicular sections, brushing
safety concerns, if any, associated with its use. It is the
each section across the initial painted section. The perpendicu-
responsibility of the user of this standard to establish appro-
lar sections are repeated at agreed upon time intervals. After
priate safety and health practices and determine the applica-
drying,wetedgeisrecordedasthelasttimethetestpaintcould
bility of regulatory limitations prior to use.
be brushed into the initial painted section without the edges of
the first coat being visible. The time at which the X marks
2. Referenced Documents
become visible is also noted.
2
2.1 ASTM Standards:
D3924 Specification for Environment for Conditioning and
5. Significance and Use
Testing Paint, Varnish, Lacquer, and Related Materials
5.1 Latex paints dry very quickly which often causes
D5068 Practice for Preparation of Paint Brushes for Evalu-
difficulty in final appearance of painted areas, especially paints
ation
formulated below 100g/L VOC where lower amounts of
D5301 Practice for Physical Characterization of Paint
solvents are in the formulated latex paint. This method is a
Brushes
means of determining the time available before a test paint
E177 Practice for Use of the Terms Precision and Bias in
cannot be worked into a previously painted area.
ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to
6. Apparatus
Determine the Precision of a Test Method
6.1 Constant Temperature/Humidity Room (23 6 2°C (73.5
3. Terminology
6 3.5°F)) / 50 6 5 % relative humidity in accordance with
3.1 Definitions:
Specification D3924.
3.1.1 open time, n—the length of time a coating remains wet
6.2 Contrasting Sealed Chart (that is, black sealed chart for
or open enough to allow for brush-in without the edges of the
white paints or white sealed chart for tinted paints), typically
first coat becoming visible and allowing for repair within the
30 by 60 cm (1 by 2 ft.).
previously painted area.
6.3 Glass Plate, 30 by 60 cm (1 by 2 ft.) or vacuum plate.
4. Summary of Test Method
6.3.1 If using a glass plate, tape to secure sealed chart to
glass plate.
4.1 Since environmental conditions such as temperature,
humidity and air flow can result in variable results, it is
6.4 Good Quality Brush, 50 mm (2 in.) wide with straight
recommended that this test method be performed in a constant
edge, polyester bristles in accordance with Practice D5301.
6.5 Timer or Clock to record time intervals.
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint
6.6 Film Applicator, capable of applying a film with a width
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.42 on Architectural Coatings.
of 7.5 cm (3 in.) and approximate wet film thickness of 75
Current edition approved July 1, 2011. Published August 2011. Originally
microns (3 mil).
approved in 2010. Last previous edition approved in 2010 as D7488 - 10. DOI:
10.1520/D7488–11.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 7. Procedure
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
7.1 Condition the brush in with the test paint accordance
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. with Practice D5068.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7488 − 11
7.7 At agreed upon time intervals between each X mark,
start brushing the first X mark in perpendicular direction to the
initial drawdown using ten strokes back and forth (1 stroke =
1 back and forth motion) to work the brush-applied paint into
thedrawdownarea.Thelengthofthestrokesshouldbeslightly
less than the width of the chart and moving across and pass the
initial drawdown
...
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:D 7488–10 Designation:D7488–11
Standard Test Method for
1
Open Time of Latex Paints
This standard is issued under the fixed designation D7488; 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 test method covers a procedure to determine the length of time a latex paint remains “wet” or “open” enough to allow
for brush-in and repair.
1.2 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
2.1 ASTM Standards:
D3924 Specification for Environment for Conditioning and Testing Paint, Varnish, Lacquer, and Related Materials
D5068 Practice for Preparation of Paint Brushes for Evaluation
D5301 Practice for Physical Characterization of Paint Brushes
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions:
3.1.1 open time, n—the length of time a coating remains wet or open enough to allow for brush-in without the edges of the first
coat becoming visible and allowing for repair within the previously painted area.
4. Summary of Test Method
4.1 Since environmental conditions such as temperature, humidity and air flow can result in variable results, it is recommended
that this test method be performed in a constant temperature / humidity room (23 6 2°C (73.5 6 3.5°F)) / 50 6 5 % relative
humidity. Test paints are applied to the center of a sealed chart with a 76 microns (3 mil) wet film thickness. X marks are made
immediately.The number of X marks will depend on how many can fit on one drawdown (see Fig. 1).The test paint is then applied
inperpendicularsections,brushingeachsectionacrosstheinitialpaintedsection.Theperpendicularsectionsarerepeatedatagreed
upontimeintervals.Afterdrying,wetedgeisrecordedasthelasttimethetestpaintcouldbebrushedintotheinitialpaintedsection
without the edges of the first coat being visible. The time at which the X marks become visible is also noted.
5. Significance and Use
5.1 Latex paints dry very quickly which often causes difficulty in final appearance of painted areas, especially paints formulated
below 100g/LVOC where lower amounts of solvents are in the formulated latex paint. This method is a means of determining the
time available before a test paint cannot be worked into a previously painted area.
6. Apparatus
6.1 Constant Temperature/Humidity Room (23 6 2°C (73.5 6 3.5°F)) / 50 6 5 % relative humidity in accordance with
Specification D3924.
6.2 Contrasting Sealed Chart (that is, black sealed chart for white paints or white sealed chart for tinted paints), typically 30
by 60 cm (1 by 2 ft.).
1
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 Dec. 1, 2010. Published February 2011. DOI: 10.1520/D7488–10.
Current edition approved July 1, 2011. Published August 2011. Originally approved in 2010. Last previous edition approved in 2010 as D7488 - 10. DOI:
10.1520/D7488–11.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. 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.
1
---------------------- Page: 1 ----------------------
D7488–11
FIG. 1 Illustration
6.3 Glass Plate, 30 by 60 cm (1 by 2 ft.) or vacuum plate.
6.3.1 If using a glass plate, tape to secure sealed chart to glass plate.
6.4 Good Quality Brush, 50 mm (2 in.) wide with straight edge, polyester bristles in accordance with Practice D5301.
6.5 Timer or Clock to record time intervals.
6.6 Film Applicator, capable of applying a film with a width of 7.5 cm (3 in.) and approximate wet film thickness of 75 microns
(3 mil).
7. Procedure
7.1Condition the brush in accordance with Practice
7.1 Condition the br
...
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