ASTM D3723-84(1999)
(Test Method)Standard Test Method for Pigment Content of Water-Emulsion Paints by Low-Temperature Ashing
Standard Test Method for Pigment Content of Water-Emulsion Paints by Low-Temperature Ashing
SCOPE
1.1 This test method covers a procedure for the pigment content determination of water-based paints. It is applicable only to pigments that do not decompose or lose weight at temperatures below 500°C. Such pigments include most metal oxides, silicates, and a majority of anhydrous inorganic salts.
1.2 Many water-based paints contain pigments and organic colorants that lose water of hydration or decompose at this temperature. The residual ash should be carefully inspected for changes in color or texture that could indicate a pigment alteration and hence lead to erroneous results. Caution should therefore be exercised when applying this test method to samples containing unknown pigment compositions.
1.3 This standard does not purport to address the safety problems 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:D3723–84 (Reapproved 1999)
Standard Test Method for
Pigment Content of Water-Emulsion Paints by Low-
Temperature Ashing
This standard is issued under the fixed designation D 3723; 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 5. Reagents
1.1 This test method covers a procedure for the pigment 5.1 Purity of Reagents—Reagent grade chemicals shall be
content determination of water-based paints. It is applicable used in all tests. Unless otherwise indicated, it is intended that
only to pigments that do not decompose or lose weight at all reagents shall conform to the specifications of the Commit-
temperatures below 500°C. Such pigments include most metal tee onAnalytical Reagents of theAmerican Chemical Society,
oxides, silicates, and a majority of anhydrous inorganic salts. where such specifications are available. Other grades may be
1.2 Many water-based paints contain pigments and organic used, provided it is first ascertained that the reagent is of
colorants that lose water of hydration or decompose at this sufficiently high purity to permit its use without lessening the
temperature. The residual ash should be carefully inspected for accuracy of the determination.
changes in color or texture that could indicate a pigment 5.2 Purity of Water—Unless otherwise indicated, references
alteration and hence lead to erroneous results. Caution should to water shall be understood to mean reagent water conforming
therefore be exercised when applying this test method to to Type III of Specification D 1193.
samples containing unknown pigment compositions. 5.3 Ammonium Hydroxide —Add 1 volume of concen-
1.3 This standard does not purport to address all of the trated NH OH (sp gr 0.90) to 3 volumes of water.
safety concerns, if any, associated with its use. It is the
6. Procedure
responsibility of the user of this standard to establish appro-
6.1 Mix samples until homogeneous, preferably on a me-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. chanical shaker. If air bubbles become entrapped in a sample,
stir it by hand.
2. Referenced Documents
6.2 Draw approximately 1.5 g of the test paint into a 5-mL
2.1 ASTM Standards: syringe and weigh to 1 mg. Add the paint dropwise (about 30
D 1193 Specification for Reagent Water drops) into a tared-aluminum foil dish that contains 2 mL of
water (5.2). Swirl the dish during the addition and continue the
3. Significance and Use
swirling until the specimen is completely dispersed. Reweigh
3.1 This test method is used by paint producers and con-
the syringe to 1 mg. Transfer between 0.4 and 0.6 g of sample
sumers for product process control and for product acceptance. to the dish. If not, adjust the transferred volume and prepare a
new specimen. If the specimen agglomerates or forms a lump
4. Apparatus
that cannot be dispersed, a drop or two of ammonia (5.3) may
4.1 Oven, forced draft, maintained at 105 6 2°C.
facilitate the dispersement. If the lumping persists, discard the
4.2 Furnace, muffle, maintained at 450 6 25°C.
specimen and prepare a new one. Prepare a duplicate specimen
4.3 Syringe, 5-mL.
in the same manner.
4.4 Aluminum Foil Dish, 58 mm in diameter by 18 mm high
6.3 Dry the specimen and dishes in the 105 6 2°C oven for
with a flat bottom. The bottom of the dish should be as nearly
a minimum of 1 h after making certain that the dishes are level.
flat as possible so that a uniform film is produced.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
This test method is under the jurisdiction of ASTM Committee D-1 on Paint listed by the American Chemical Society, see Analar Standards for Laboratory
and Related Coatings, Materials, andApplications and is the direct responsibility of Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Subcommittee D01.21 on Chemical Analysis of Paints and Pa
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