ASTM D4946-89(2017)

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: D4946 − 89 (Reapproved 2017)
Standard Test Method for
Blocking Resistance of Architectural Paints
This standard is issued under the fixed designation D4946; 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 covers an accelerated procedure for 4.1 Dried paint films are placed face-to-face and a pressure
evaluating the face-to-face blocking resistance of trades sales of about 127 g/cm (1.8 psi) is applied. These paint films are
paints. This is not to be confused with blocking resistance Test put into an oven for 30 min to make the test more stringent.
Method D3003, which is concerned with blocking of industrial After cooling, the blocked panels are peeled apart. The degree
coatings on metal substrates, nor with Test Method D2793 of blocking is rated subjectively for tack or seal using a series
which is concerned specifically with wood product finishes and of standard descriptive terms corresponding to numerical
reports results on a satisfactory or not satisfactory basis, rather ASTM values of 10 to 0.
than by the degree of blocking tendency as in this test method.
5. Significance and Use
1.2 The values stated in the SI units of measurement are to
5.1 Dry paint often comes in contact with itself especially in
be regarded as the standard. The values given in parentheses
window and door areas and, depending on its hardness, the
are for information only.
pressure, temperature, humidity, and duration of time the
1.3 This standard does not purport to address all of the
surfaces are in contact, sometimes sticks to itself (blocks).This
safety concerns, if any, associated with its use. It is the
stringent test method can be used to compare and rate
responsibility of the user of this standard to establish appro-
subjectively the resistance of paints to blocking.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
6. Apparatus
6.1 Conditioned Room, at 18 to 29.5°C (65 to 85°F) and 40
2. Referenced Documents
to 60 % relative humidity.
2.1 ASTM Standards:
6.2 Sealed Paper Test Charts, approximately 190 by 280
D16 TerminologyforPaint,RelatedCoatings,Materials,and
mm (7.5 by 11 in.).
Applications
D2793 Test Method for Block Resistance of Organic Coat- 6.3 Applicator Blade, 13 to 15 cm (5 to 6 in.) wide,
ings on Wood Panel Substrates 0.15-mm (6-mil) clearance.
D3003 Test Method for Pressure Mottling and Blocking
6.4 Oven, 48 to 52°C (115 to 125°F).
Resistance of Organic Coatings on Metal Substrates
6.5 Rubber Stoppers, No. 8, 3.2 cm (1.25 in.) smaller
diameter.
3. Terminology
6.6 Weights, 1000 g.
3.1 Definitions:
3.1.1 blocking, n—the undesirable sticking together of two
6.7 Scissors.
painted surfaces when pressed together or placed in contact
6.8 Aluminum Tray or Pan, flat.
with each other for an extended period of time, as referenced in
Terminology D16.
7. Procedure
7.1 Cast the paint to be tested on a sealed test chart using the
applicator blade. Condition coated panels in the conditioned
This test method is under the jurisdiction of ASTM Committee D01 on Paint
room for seven days. All painted panels should be kept free of
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.42 on Architectural Coatings.
grease, oil, or fingerprints since these will affect block resis-
Current edition approved Feb. 1, 2017. Published February 2017. Originally
tance.
approved in 1989. Last previous edition approved in 2012 as D4946 – 89 (2012).
DOI: 10.1520/D4946-89R17.
7.2 After the panels have been conditioned, cut out six 3.8
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1 1
by 3.8-cm (1 ⁄2 by 1 ⁄2-in.) sections from the painted chart.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Start the cut at least 1.3 cm ( ⁄2 in.) away from the edge
...