ASTM D7540-09(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: D7540 − 09 (Reapproved 2019)
Standard Practice for
Dispersion of Chromatic Pigments with a Mechanical
Muller
This standard is issued under the fixed designation D7540; 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 D3022 Test Method for Color and Strength of Color Pig-
ments by Use of a Miniature Sandmill
1.1 This practice is intended to be used to disperse a
E284 Terminology of Appearance
chromatic pigment for subsequent testing.
1.2 This practice does not apply to white pigments.
3. Terminology
NOTE1—ThedispersionportionofTestMethodD3022issimilartothis
3.1 Definitions—Definitions of appearance terms used in
practice, but it utilizes a miniature sandmill rather than a mechanical
this practice may be found in Terminology E284.
muller, to disperse the chromatic pigment.
NOTE 2—The dispersion portions ofTest Methods D332 and D2745 are
similar to this practice, but they are intended for use with white pigments,
4. Summary of Practice
rather than chromatic pigments.
4.1 Pigments are dispersed in a suitable vehicle with a
1.3 The values stated in SI units are to be regarded as the
mechanical muller. Test and standard pigments are treated
standard. The values given in parentheses are for information
identically. Opaque drawdowns may be made from the disper-
only.
sions and compared for color and strength differences either
1.4 This standard does not purport to address all of the
visually or instrumentally.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Significance and Use
priate safety, health, and environmental practices and deter-
5.1 The results obtained with a mechanical muller do not
mine the applicability of regulatory limitations prior to use.
necessarily correlate directly with an industrial situation where
Specific hazard statements are given in Section 8.
different dispersing conditions exist. However, dispersion with
1.5 This international standard was developed in accor-
a mechanical muller is a quick and inexpensive way to prepare
dance with internationally recognized principles on standard-
specimens for testing the color and strength of a pigment for
ization established in the Decision on Principles for the
routine quality control.
Development of International Standards, Guides and Recom-
5.2 By following the procedure described in Appendix X1,
mendations issued by the World Trade Organization Technical
the conditions for achieving the maximum practical degree of
Barriers to Trade (TBT) Committee.
dispersion with a mechanical muller may be determined. Any
color and strength tests done with the dispersions should be
2. Referenced Documents
carried out under these conditions.
2.1 ASTM Standards:
D332 Test Method for Relative Tinting Strength of White
6. Apparatus
Pigments by Visual Observation
6.1 Balances—(1) A balance sensitive to 10 mg, and (2)an
D2745 Test Method for Relative Tinting Strength of White
analytical balance sensitive to 1.0 mg.
Pigments by Reflectance Measurements
6.2 Muller, Mechanical, equipped with ground-glass plates
to which a variable but known force may be added in 220-N
(50-lbf) increments. The driven glass plate shall have a speed
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
ofrotationofbetween70and120r/minandtheapparatusshall
Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.24 on Physical Properties of Liquid Paints & Paint Materials.
have an arrangement for pre-setting the number of revolutions
Current edition approved April 1, 2019. Published April 2019. Originally
in multiples of 50. See Fig. 1 for an example of such a device.
approved in 2009. Last previous edition approved in 2013 as D7540 – 09 (2013).
DOI: 10.1520/D7540-09R19.
6.3 Rubbing Surfaces—The rubbing surfaces of the ground-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
glass plates shall be kept sharp by removing them from the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
muller and grinding them face-to-face with No. 303 optical
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. emery, or its equivalent, and water.
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D7540 − 09 (2019)
9. Dispersing Conditions
9.1 The conditions for dispersing the pigment on the me-
chanical muller should be such that the maximum tinting
strength is developed. For each pigment and each dispersing
vehicle the development of tinting strength by the mechanical
muller is influenced by the force applied, the number of
revolutions, the mass of the pigment, and the mass of the
vehicle. The conditions for obtaining the maximum tinting
strength with the mechanical muller can be determined by
following the procedure in Appendix X1.
9.2 If these conditions are known for a particular pigment
with a particular vehicle, or if the purchaser and seller agree
upon a particular set of conditions, there is no need to carry out
the procedure in Appendix X1.
10. Dispersion Procedure
10.1 Decide, by agreement or by experimentation, as dis-
cussed in Section 9, the following dispersing conditions:
10.1.1 Force applied to the muller plates;
10.1.2 Number of revolutions;
10.1.3 Mass of the pigment; and
10.1.4 Mass of the vehicle.
10.2 Applying these decisions, prepare a dispersion of the
FIG. 1 A Muller-Type Laboratory Grinder/Disperser (Courtesy of reference standard pigment. Weigh onto a glass slab to within
Paul N. Gardner Company, Inc.)
2 mg, the appropriate quantities of the standard pigment and
the dispersing vehicle. Mix the pigment and vehicle together
6.4 Small Glass Slab or other nonabsorbent material, suit-
thoroughly with the spatula and transfer the mixture to the
ab
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