ASTM D2745-00

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Designation: D 2745 – 00
Standard Test Method for
Relative Tinting Strength of White Pigments by Reflectance
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Measurements
This standard is issued under the fixed designation D 2745; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope reflectance) of the wet films are measured. The relative tinting
strength of the test pigment is calculated directly from the
1.1 This test method describes the procedure for determin-
reflectance values.
ing the relative tinting strength of white pigments by reflec-
tance measurements of black tints.
4. Significance and Use
1.2 This test method is applicable only for comparing the
4.1 Tinting strength is one of the most important properties
test pigment with a reference standard of the same type and
of a white pigment. This test method provides a means of
grade.
testing this property for quality control.
NOTE 1—Test Method D 332 describes a procedure for visual assess-
4.2 This test method is a referee method, and the vehicle for
ment of blue-tinted samples.
preparingthedispersionandtheblackfortintingaresuggested,
1.3 The values stated in SI units are to be regarded as the
but others may be used provided both the purchaser and the
standard. The values given in parentheses are for information
seller agree to the changes.
only.
4.3 The results obtained with a muller do not necessarily
1.4 This standard does not purport to address all of the
agree with industrial situations where different dispersing
safety concerns, if any, associated with its use. It is the
conditions exist. However, dispersing with a muller is a fast,
responsibility of the user of this standard to establish appro-
relatively inexpensive way of testing tinting strength for
priate safety and health practices and determine the applica-
routine quality control.
bility of regulatory limitations prior to use.
5. Apparatus and Materials
2. Referenced Documents
5.1 Muller, automatic, equipped with a weight that exerts a
2.1 ASTM Standards:
permanent 220-N (50-lbf) and an additional weight exerting a
D 332 Test Method for Relative Tinting Strength of White
50-lbf making a total of 445-N (100-lbf). The two glass plates
2
Pigments by Visual Observation
shallbekeptsharpbyremovingfromthemachineandgrinding
D 2244 Test Method for Calculation of Color Differences
them face-to-face with No. 303 optical emery or equivalent,
2
From Instrumentally Measured Color Coordinates
and water.
5.2 Spatula—A flexible spatula having a chromium-plated
3. Summary of Test Method
or plastic blade 75 to 150 mm (3 to 6 in.) long, and another
3.1 Pigment is dispersed in a vehicle and let down with
with a 75 mm ( 3-in.) tapered blade.
additional vehicle that has been tinted. Dispersion and letdown
5.3 Balances—(1) A balance sensitive to 20 mg and (2)an
are accomplished with a mechanical muller. Both the test and
analytical balance sensitive to 0.4 mg.
standard pigments are treated identically. Opaque drawdowns
5.4 Vehicle—Because the choice of vehicle may affect
are made of the paint and the Y tristimulus values (green-filter
results, a solvent-free vehicle (excluding refined or low-bodied
linseed oil) should be agreed upon by the purchaser and the
seller.
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5.5 Tinting Black—A lamp black predispersed in a vehicle
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
similar in nature to the test vehicle. Tinting black should be
Subcommittee D01.26 on Optical Properties.
agreed upon between the purchaser and the seller.
Current edition approved Nov. 10, 2000. Published January 2001. Originally
5.6 Chart—Either gray or white lacquered charts cut to a
published as D 2745 – 68 T. Last previous edition D 2745 – 93.
2
Annual Book of ASTM Standards, Vol 06.01. convenient size.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D2745–00
method. (2)Add the vehicle to a tared metal or plastic plate till the correct
5.7 Color Measuring Instruments, meeting the requirements
weight is reached; transfer to the muller by scraping off the plate with the
of Test Method D 2244.
spatula. If the vehicle tends to run, weigh both pigment and vehicle on the
5.8 Film Applicator— 50 or 75 mm (2 or 3 in.) wide with a
plate making a crater in the pile of pigment to contain the vehicle.
clearanceof150µm(6mils)toproducewetfilmsabout75µm
(3 mils ) thick. This applicator when used as suggested in the 7.4 Standardize the color measuring instrumen
...