ASTM D185-84(1999)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D185–84(Reapproved1999)
Standard Test Methods for
Coarse Particles in Pigments, Pastes, and Paints
This standard is issued under the fixed designation D 185; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 5. Procedure for Insoluble Dry Pigments, Except Metallic
Aluminum and Bronze Powders
1.1 These test methods cover the determination of the
amount of coarse particles in dry pigments and of coarse 5.1 Dry the sieve in an oven at 105 6 2°C, cool, and then
particles and skins in mixtures of pigments and vehicles. weigh on an analytical balance, recording the weight to 1 mg.
1.2 The values stated in inch-pound units are to be regarded 5.2 Weigh a specimen (25 g for basic carbonate and basic
as the standard. The values given in parentheses are for sulfate white leads, 25 g for red lead and mercuric oxide, 2 g
information only. for black pigments of low specific gravity, 3 g for Prussian
1.3 This standard does not purport to address all of the blues and graphite, and 10 g for all other pigments) of the
safety concerns, if any, associated with its use. It is the pigment to be tested on an analytical balance to 1 mg. Wet the
responsibility of the user of this standard to establish appro- sieve on both sides with alcohol and transfer the specimen of
priate safety and health practices and determine the applica- pigment to the sieve and wet with alcohol.
bility of regulatory limitations prior to use. 5.3 Hold the sieve under a tap delivering about 300 to 500
mL of the wash liquid (water) per minute. By slightly shaking
2. Referenced Documents
the sieve, the pigment will be rapidly carried through. A soft
2.1 ASTM Standards:
camel’s-hair brush may be used in aiding the operation. If the
E 11 Specification for Wire-Cloth Sieves for Testing Pur- sieve is held at a slight angle so that the pigment gradually
poses
collects at one edge during the washing process, and then
rotated, the pigment may be brushed out rapidly, with no risk
3. Significance and Use
of clogging the sieve.
3.1 In production of paints, smoothness of the paint film is
5.4 After most of the finely divided portion of the pigment
of paramount importance. Agglomerates or coarse particles
has passed through the sieve (from 2 min to 1 h, according to
larger than 45 µm are difficult to disperse and may prevent
the kind of pigment), place the sieve in an 8-in. (200-mm)
obtaining a smooth film. These test methods are a valuable
porcelain dish containing 250 mLof the wash liquid so that the
quality control test for grading raw materials.
sieve is covered to a depth of about ⁄2 in. Brush the pigment
remaining on the sieve with a soft 1-in. (25-mm) camel’s-hair
4. Apparatus
brush at the rate of two strokes per second during two periods
4.1 The apparatus shall consist of a 3-in. (75-mm) 45-µm
of 10 s each. Raise the sieve from the dish after each 10-s
(No. 325) sieve conforming to Specification E 11. A3-in.
period to let the liquid on the sieve run through. Change the
45-µm sieve for comparison purposes should be retained in the
liquid in the dish after every two brushing periods. Continue
laboratory as a reference standard. Whenever a new sieve is
thisoperationuntilthewashliquidpassingovertheresidueand
secured, a practical test of its accuracy should be made by
through the sieve is clear and free from solid particles. When
running on it and on the reference standard sieve a comparison
the washing appears to be complete, collect about 200 mL of
test, using a pigment that has a considerable amount of coarse
the wash liquid, after passing over the residue and through the
particles.Areserve stock of such a pigment should be kept for
sieve, in a clean 400-mLbeaker. Stir the liquid vigorously, and
this purpose.
set the beaker on a black surface in the case of white pigments
and on a white surface in the case of colored pigments. The
washing is not considered complete until such a test fails to
ThesetestmethodsareunderthejurisdictionofASTMCommitteeD-1onPaint
show any particles collected about the middle of the bottom of
and Related Coatings, Materials, and Applications, and are the direct responsibility
the beaker.
of Subcommittee D01.31 on Pigment Specifications.
Current edition approved Oct. 26, 1984. Published December 1984. Originally
NOTE 1—Occasionally, pigments will be found that foam when water is
published as D 185–37. Last previous edition D 185–78.
used as the wash liquid. In such instances, during the last washing in the
Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D185
porcelain dish the use of a liquid that breaks down the foaming and is
to a piece of white bond paper and gently rub the carbon onto
readily miscible with water, such as alcohol, will usually overcome this
the paper with the finger. When no further real blackening of
difficulty.
the paper occurs, carefully transfer the residue to the balance
5.5 When the washing is complete wash the pigment par-
pan, weigh, and recalculate the percent of coarse particles.
ticlesadheringtothebrushbackontothesieveandwipeoffthe
8. Procedure for Water-Soluble Pigments, Pastes in Oil,
water below the sieve.Add a few drops of alcohol and then of
Pastes in Japan, and Mixed Paints
ether to expedite drying. Dry the sieve for1hat 105°C, cool,
and weigh as described in 5.1. Calculate the percent of coarse 8.1 Dry, cool, and weigh the sieve as described in 5.1.
particles. 8.2 For water-soluble pigments use 10 6 1gasthe
specimen. For pastes in oil, pastes in Japan, and mixed paints
6. Procedure for Metallic Aluminum and Bronze
use 256 1 g as the specimen. For white leads and red lead use
Powders
50 6 1 g as the specimen.
6.1 In the case of metallic aluminum and bronze powders 8.3 Weigh the specimen to 1 mg and transfer to a 250-mL
follow the procedure described in Section 5 except use5gof beaker. Slowly add 100 mL of kerosine to the contents of the
beaker, mixing thoroughly by use of a stirring rod with
the material as the specimen and denatured alcoh
...