ASTM D281-95(2007)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D281–95(Reapproved2007)
Standard Test Method for
Oil Absorption of Pigments by Spatula Rub-out
This standard is issued under the fixed designation D281; 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 action.Becausetheendpointsaredifferent,thevaluesobtained
from the two test methods generally differ.
1.1 This test method covers the determination of the oil
absorption of pigments by the spatula rub-out technique.
5. Apparatus and Materials
1.2 The values stated in SI units are to be regarded as
5.1 Balance, capable of weighing to 0.001 g.
standard. No other units of measurement are included in this
5.2 Dropping Bottle, fitted with ground-in pipet and rubber
standard.
bulb or buret, graduated in 0.1-mL divisions.
1.3 This standard does not purport to address all of the
5.3 Smooth Glass Rub-up Plate or Marble Slab (glass
safety concerns, if any, associated with its use. It is the
should have a surface similar to Hoover Muller Plates).
responsibility of the user of this standard to establish appro-
5.4 Spatula, sharp-edged, steel, having a blade of 15 or 20
priate safety and health practices and determine the applica-
1 3
mm by 100 mm ( ⁄2 or ⁄4 by 4 in.).
bility of regulatory limitations prior to use.
5.5 Oil, linseed, raw, conforming to Specification D234
2. Referenced Documents except that it shall have an acid number of 3 6 1. Linseed oil
used in comparative tests must have the same acid value. Other
2.1 ASTM Standards:
3 liquids, such as refined oil, may be used by mutual agreement.
D234 Specification for Raw Linseed Oil
D1483 Test Method for Oil Absorption of Pigments by
6. Procedure
Gardner-Coleman Method
6.1 Procedure A (Weighing Bottle)—Weigh exactly 1 g, or
3. Summary of Test Method any multiple thereof (Note 1), of the thoroughly mixed and air
dried pigment and place upon a glass plate or marble slab.
3.1 A stiff, putty-like paste is formed by the dropwise
Weigh to 0.01 g a dropping bottle containing raw linseed oil
addition of linseed oil to pigment that is being thoroughly
along with the pipet and rubber bulb. Add the linseed oil
rubbed with a spatula. The amount of oil required to produce
gradually,dropbydrop(bymeansofthepipet),tothepigment.
the end point is used to calculate an oil absorption value.
After the addition of each drop, thoroughly incorporate the oil
4. Significance and Use
by rubbing up with the spatula. The test is complete when
exactly enough oil has been incorporated with the pigment to
4.1 The oil absorption value obtained by this test method
produce a very stiff, putty-like paste, that does not break or
gives information about the vehicle demand of the pigment
separate. Weigh the bottle and oil to 0.01 g and determine by
whenitisusedinapigmentpaste.Oilabsorptionvaluescanbe
difference the weight of oil used.
used to characterize pigments or batches of a given pigment.
4.2 ThistestmethoddiffersfromTestMethodD1483inthat
NOTE 1—The specimen weight depends upon the specific gravity,
D1483 involves only a gentle stirring and folding of the
fineness, and other characteristics of the pigment. For example, 20 g is
pigment, whereas this test method requires a thorough rubbing taken for white lead, but about 1 g is sufficient for carbon black. In any
event, the specimen size should be large enough so that at least1gofoil
is required.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
6.2 Procedure B (Buret):
and Related Coatings, Materials, andApplications and is the direct responsibility of
6.2.1 Follow ProcedureA, except add the linseed oil from a
Subcommittee D01.24 on Physical Properti
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