Standard Test Methods for Coarse Particles in Pigments

SIGNIFICANCE AND USE
In production of paints, smoothness of the paint film is of paramount importance. Agglomerates or coarse particles larger than 45 μm are difficult to disperse and may prevent obtaining a smooth film. These test methods are a valuable quality control test for grading raw materials.
SCOPE
1.1 These test methods cover the determination of the amount of coarse particles in dry pigments.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
This standard does not purport to address all of the safety concerns, if any, 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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Historical
Publication Date
30-Jun-2007
Current Stage
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ASTM D185-07 - Standard Test Methods for Coarse Particles in Pigments
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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 − 07
StandardTest Methods for
1
Coarse Particles in Pigments
This standard is issued under the fixed designation D185; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope test, using a pigment that has a considerable amount of coarse
particles.Areserve stock of such a pigment should be kept for
1.1 These test methods cover the determination of the
this purpose.
amount of coarse particles in dry pigments.
1.2 The values stated in SI units are to be regarded as the
5. Procedure for Insoluble Dry Pigments, Except Metallic
standard. The values given in parentheses are for information
Aluminum and Bronze Powders
only.
5.1 Weigh approximately 100 g of a pigment specimen to
1.3 This standard does not purport to address all of the
the nearest
safety concerns, if any, associated with its use. It is the
0.1 g on an analytical balance.Wet the sieve on both sides with
responsibility of the user of this standard to establish appro-
water and transfer the pigment to the sieve.
priate safety and health practices and determine the applica-
5.2 Hold the sieve under a tap delivering about 300 to 500
bility of regulatory limitations prior to use.
mL of the wash liquid (water) per minute. Slightly shake the
sieve and move the stream of water around on the pigment in
2. Referenced Documents
the sieve to get the pigment to pass through the sieve. Use a
2
2.1 ASTM Standards:
soft camel-hair brush to help the pigment wet out and pass
E11 Specification for Woven Wire Test Sieve Cloth and Test
through the sieve. If the sieve is held at a slight angle so that
Sieves
the pigment gradually collects at one edge during the washing
process, and then rotated, the pigment may be brushed out
3. Significance and Use
rapidly, with no risk of clogging the sieve. Continue the water
3.1 In production of paints, smoothness of the paint film is
rinsing and brushing until no more pigment is passing through
of paramount importance. Agglomerates or coarse particles
the sieve. This can be checked by tilting the sieve and
larger than 45 µm are difficult to disperse and may prevent
inspecting the water passing through for pigment.
obtaining a smooth film. These test methods are a valuable
5.3 When pigment is no longer passing through the sieve,
quality control test for grading raw materials.
adjust the tap to a slow stream of water. Tilt the sieve and flow
water through to collect the retained material in one place near
4. Apparatus
the edge.Then tilt the sieve more so that the slow flow of water
4.1 The apparatus shall consist of a 200-mm (8-in.) 45-µm
strikes the bottom of the screen and rinses out completely the
(No. 325) sieve conforming to Specification E11. An 8-in.
retained particles into a 100 m
...

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