ASTM D7867-13(2020)
(Test Method)Standard Test Methods for Measurement of the Rotational Viscosity of Paints, Inks and Related Liquid Materials as a Function of Temperature
Standard Test Methods for Measurement of the Rotational Viscosity of Paints, Inks and Related Liquid Materials as a Function of Temperature
SIGNIFICANCE AND USE
5.1 The viscosity of paint, inks and many related liquid materials is dependent on temperature. It is useful to know the extent of this dependence. One use of such information is to prepare a viscosity-temperature table or curve. Then, if ambient conditions do not allow the measurement of viscosity at the exact temperature stated in a specification or regulation, the viscosity measured at ambient temperature can be used to determine the viscosity at the temperature of interest through the use of the previously prepared table or curve. Viscosity measurements that cover a range of shear rates as well as temperatures could include shear rates associated with paint application or allow extrapolation to such shear rates. This information would enable a producer or user to estimate the effect on application of heating the paint.
SCOPE
1.1 These test methods cover the use of rotational viscometers to determine the dependence of apparent viscosity of paints, inks and related liquid materials on temperature. The first method uses a standard rotational viscometer with concentric cylinder geometry running at a fixed rotational speed as the temperature is increased or decreased. The second method uses a rotational viscometer with cone and plate geometry running at a fixed rotational speed as the temperature is increased or decreased. The third method uses concentric cylinder or cone/plate geometry operated with a shear rate ramp at several discrete temperatures.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard may involve hazardous materials, operations and equipment. 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7867 − 13 (Reapproved 2020)
Standard Test Methods for
Measurement of the Rotational Viscosity of Paints, Inks and
Related Liquid Materials as a Function of Temperature
This standard is issued under the fixed designation D7867; 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.
1. Scope D3925 Practice for Sampling Liquid Paints and Related
Pigmented Coatings
1.1 These test methods cover the use of rotational viscom-
eters to determine the dependence of apparent viscosity of
3. Terminology
paints, inks and related liquid materials on temperature. The
first method uses a standard rotational viscometer with con- 3.1 Definitions:
centric cylinder geometry running at a fixed rotational speed as
3.1.1 apparent viscosity, n—viscosity that is not a true
the temperature is increased or decreased. The second method
propertyofthefluid,butavariabledependingontheshearrate.
uses a rotational viscometer with cone and plate geometry
3.1.2 shear thinning fluid—fluid in which the apparent
running at a fixed rotational speed as the temperature is
viscosity decreases with increasing shear rate.
increased or decreased. The third method uses concentric
cylinder or cone/plate geometry operated with a shear rate 3.1.3 thixotropic fluid, n—fluid whose viscosity is time
ramp at several discrete temperatures.
dependent, that is, its viscosity decreases with the time it is
subjected to shear.
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
3.1.4 viscosity, n—the ratio between an applied shear stress
standard.
to the resulting shear rate (velocity gradient) is defined as the
dynamic viscosity; it is a measure of the resistance to flow of
1.3 This standard may involve hazardous materials, opera-
a fluid.
tionsandequipment. This standard does not purport to address
all of the safety concerns, if any, associated with its use. It is
4. Summary of Test Methods
the responsibility of the user of this standard to establish
appropriate safety, health, and environmental practices and
4.1 Test Method A is run with a viscometer with concentric
determine the applicability of regulatory limitations prior to
(coaxial) cylinder capability, either built-in or as an accessory
use.
that allows use of small specimen size (2 to 20 mL). This test
1.4 This international standard was developed in accor-
is used for measuring apparent viscosity as a function of
dance with internationally recognized principles on standard-
temperature at low to medium shear rates. The viscosity-
ization established in the Decision on Principles for the
temperature profile of the paint, ink or other material may be
Development of International Standards, Guides and Recom-
determined at a fixed shear rate or the viscosity-shear rate
mendations issued by the World Trade Organization Technical
profile may be determined at several discrete temperatures.
Barriers to Trade (TBT) Committee.
4.2 Test Method B is accomplished with a viscometer that
2. Referenced Documents
has cone/plate test geometry. It is used to measure apparent
viscosity as a function of temperature at low to medium shear
2.1 ASTM Standards:
rates (high shear rates may cause shear heating that interferes
with temperature control). Shear heating is more likely with
1 cone/plate geometry because it permits use of a wider range of
These test methods are under the jurisdiction of ASTM Committee D01 on
Paint and Related Coatings, Materials, and Applications and is the direct responsi-
shear rates than does the concentric cylinder instrumentation in
bility of Subcommittee D01.24 on Physical Properties of Liquid Paints & Paint
Method A. The upper limit of shear rate will depend on the
Materials.
material and its viscosity. The viscosity-temperature profile of
Current edition approved Dec. 1, 2020. Published December 2020. Originally
the paint/coating may be determined at a fixed shear rate or the
approved in 2013. Last previous edition approved in 2013 as D7867 – 13. DOI:
10.1520/D7867-13R20.
viscosity-shear rate profile may be determined at several
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
discrete temperatures. The smaller specimen size compared to
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Method A permits better temperature control and more rapid
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. characterization of the viscosity-temperature profile.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7867 − 13 (2020)
4.3 Test Method C is used for determining apparent viscos- 8.6 Select proper rpm and allow the rotating cylinder to
ity as a function of a shear rate ramp at multiple discreet rotate for an agreed upon time interval and taking a reading or
temperatures. This method can be used with either coaxial wait until the reading stabilizes and note that value.
cylinder geometry or cone/plate geometry.Ashear rate ramp is
8.7 Record viscosity reading, temperature and rotational
defined and run at a discreet temperature; the viscosity values
speed. Record shear rate if measurable and needed.
at each shear rate are recorded. The shear rate ramp is then
NOTE 1—Many paints and inks are shear thinning and thixotropic.They
repeated at a series of discreet temperatures and the viscosity
havestructurethatisbrokendownbyshearing.Byallowingthesametime
interval between readings for measurements on given product, viscosity
values are measured to characterize the viscosity-temperature
differences due to differences in the degree of break-down of structure
profile for the sample specimen.
should be minimized.
4.4 Temperature control for Test Methods A, B, and C
8.8 Turn off motor after data point is collected. Increase
requires use of an apparatus that maintains test sample tem-
temperature to next level. Allow the specimen and inner
perature within 60.2°C of the specified set point. Control to
cylinder to come to equilibrium. The time for thermal equili-
within 60.1°C is preferred if achievable.
bration will vary with the instrument and the size and mass of
the cylinders.
5. Significance and Use
8.9 Repeat steps 8.4 – 8.8 as needed until the desired
5.1 The viscosity of paint, inks and many related liquid
temperature range had been covered.
materials is dependent on temperature. It is useful to know the
NOTE 2—In the case of highly structured materials or those that dry
extent of this dependence. One use of such information is to
rapidly, it may be necessary to change the specimen between each
prepare a viscosity-temperature table or curve. Then, if ambi-
temperature change.
ent conditions do not allow the measurement of viscosity at the
exact temperature stated in a specification or regulation, the
9. Report
viscosity measured at ambient temperature can be used to
9.1 Report the following information:
determine the viscosity at the temperature of interest through
9.1.1 Reference to this test method, the viscometer model
the use of the previously prepared table or curve. Viscosity
and specific
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