ASTM D2745-93

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 2745 – 93
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Relative Tinting Strength of White Pigments by Reflectance
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 4.2 This test method is a referee method, and the vehicle for
preparing the dispersion and the black for tinting are suggested
1.1 This test method describes the procedure for determin-
but others may be used provided both the purchaser and the
ing the relative tinting strength of white pigments by reflec-
seller agree to the changes.
tance measurements of black tints.
4.3 The results obtained with a muller do not necessarily
1.2 This test method is applicable only for comparing the
agree with industrial situations where different dispersing
test pigment with a reference standard of the same type and
conditions exist. However, dispersing with a muller is a fast,
grade.
relatively inexpensive way of testing tinting strength for
NOTE 1—Test Method D 332 describes a procedure for visual assess-
routine quality control.
ment of blue tinted samples.
5. Apparatus and Materials
1.3 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the
5.1 Muller, automatic, equipped with a weight that exerts a
responsibility of the user of this standard to establish appro-
permanent 50-lbf (220-N) and an additional weight exerting a
priate safety and health practices and determine the applica-
50-lbf making a total of 100-lbf (445-N). The two glass plates
bility of regulatory limitations prior to use.
shall be kept sharp by removing from the machine and grinding
them face-to-face with No. 303 optical emery or equivalent,
2. Referenced Documents
and water.
2.1 ASTM Standards:
5.2 Spatula—A flexible spatula having a chromium-plated
D 332 Test Method for Relative Tinting Strength of White
or plastic blade 3 to 6 in. (75 to 150 mm) long and another with
Pigments by Visual Observation
a 3-in. tapered blade.
E 97 Test Method for Directional Reflectance Factor, 45-
5.3 Balances—(1) A balance sensitive to 20 mg and (2)an
deg 0-deg, of Opaque Specimens by Broad-Band Filter
analytical balance sensitive to 0.4 mg.
Reflectometry
5.4 Vehicle—Because the choice of vehicle may affect
results, a solvent-free vehicle (excluding refined or low-bodied
3. Summary of Test Method
linseed oil) should be agreed upon by the purchaser and the
3.1 Pigment is dispersed in a vehicle and let down with
seller.
additional vehicle that has been tinted. Dispersion and letdown
5.5 Tinting Black—A lamp black predispersed in a vehicle
are accomplished with a mechanical muller. Both the test and
similar in nature to the test vehicle.
standard pigments are treated identically. Opaque drawdowns
5.6 Chart—Either gray or white lacquered charts cut to a
are made of the paint and the Y tristimulus values (green-filter
convenient size.
reflectance) of the wet films are measured. The relative tinting
5.7 Colorimeter—A filter colorimeter meeting the require-
strength of the test pigment is calculated directly from the
ments of Test Method E 97.
reflectance values.
5.8 Film Applicator—2 or 3 in. (50 or 75 mm) wide with a
4. Significance and Use
A satisfactory muller is supplied by the Hoover Color Corp., 13 Cordier St.,
4.1 Tinting strength is one of the most important properties
Irvington, NJ 07111.
of a white pigment. This test method provides a means of
Suggested vehicles include a 50-50 mixture of Aroplaz 1271 and 1278 (Spencer
Kellogg Division of Textron, Inc., P.O. Box 807, Buffalo, NY 14240), No. 3 Litho
testing this property for quality control.
Varnish (Inmont Corp., Printing Ink Div., Germantown Ave. and New Market St.,
Philadelphia, PA 19123), and Castor Oil AA, USP (NL Industries, NL Chemicals
This test method is under the jurisdiction of ASTM Committee D-1 on Paint Div., P.O. Box 700, Hightstown, NJ 08520).
and Related Coatings, Materials, and Applications and is the direct responsibility of Tinting black should be agreed upon between the purchaser and the seller.
Suggested materials include Lampblack PF 4340 (Daniel Products Co., 400
Subcommittee D01.26 on Optical Properties.
Current edition approved Sept. 15, 1993. Published November 1993. Originally Claremont Ave., Jersey City, NJ 07304) and Lampblack 5-24-A-710 (The Hilton-
published as D 2745 – 68 T. Last previous edition D 2745 – 89. Davis Chemical Co., 2235 Langdon Farm Road, Cincinnati, OH 45237).
2 7
Annual Book of ASTM Standards, Vol 06.01. Suitable charts are available from The Leneta Co., P.O. Box 86, Ho-Ho-Kus, NJ
Discontinued see 1992 Annual Book of ASTM Standards, Vol 14.02. 07423.
D 2745
TABLE 1 Examples of Preparation of Black Letdown Vehicles
Approximate Approximate
Black Letdown Predispersed
B
Pigment Type Pigment Pigment, g Clear Vehicle, g PVC of Final Clear Vehicle, g
A
Vehicle, g Black, g
Density Paint, %
Titanium dioxide:
rutile 4.1 3.000 2.000 1.000 20 6.80 93.20
anatase 3.8 3.000 2.250 1.000 20
Lithopone 4.3 5.000 1.220 1.000 35 2.25 250.00
Zinc oxide, leaded 5.9 5.000 2.460 1.000 20
Zinc oxide 5.6 5.000 2.660 1.000 20
White lead 6.8 3.000 0.810 1.000 20
A
Daniel Products Co. Lampblack F is used for this example.
B
A 50-50 (by weight) composite vehicle, Aroplaz 1271 and 1278, is the “vehicle’’ used for this example.
intended for preparing a paste on the muller. Use the weigh-by-difference
clearance of 6 mils (150 μm) to produce wet films about 3 mils
method. (2) Add the vehicle to a tared metal or plastic plate till the correct
(75 μm) thick. This applicator when used as suggested in the
8 weight is reached; transfer to the muller by scraping off the plate with the
test method will produce an R film.
‘
spatula. If the vehicle tends to run, weigh both pigment and vehicle on the
plate making a crater in the pile of pigment to contain the vehicle.
6. Standard
7.4 Standardize the colorimeter for measurement of the
6.1 A standard w
...