ASTM D7394-13
(Practice)Standard Practice for Rheological Characterization of Architectural Coatings using Three Rotational Bench Viscometers
Standard Practice for Rheological Characterization of Architectural Coatings using Three Rotational Bench Viscometers
SIGNIFICANCE AND USE
5.1 A significant feature of this practice is the ability to survey coating rheology over a broad range of shear rates with the same bench viscometers and test protocol that paint formulators and paint QC analysts routinely use. By using this procedure, measurement of the shear rheology of a coating is possible without using an expensive laboratory rheometer, and performance predictions can be made based on those measurements.
5.2 Low-Shear Viscosity (LSV)—The determination of low-shear viscosity in this practice can be used to predict the relative “in-can” performance of coatings for their ability to suspend pigment or prevent syneresis, or both. The LSV can also predict relative performance for leveling and sag resistance after application by roll, brush or spray. Fig. 1 shows the predictive low-shear viscosity relationships for several coatings properties.
5.3 Mid-Shear Viscosity (MSV)—The determination of MSV (coating consistency) in this practice is often the first viscosity obtained. This viscosity reflects the coatings resistance to flow on mixing, pouring, pumping, or hand stirring. Architectural coatings nearly always have a target specification for mid-shear viscosity, which is usually obtained by adjusting the level of thickener in the coating. Consequently, mid-shear viscosity is ideally a constant for a given series of coatings being tested to provide meaningful comparisons of low-shear and high-shear viscosity. With viscosities at the same KU value, MSV can also be used to obtain the relative Mid-Shear Thickener Efficiency (MSTE) of different thickeners in the same coating expressed as lb thickener/100 gal wet coating or g thickener/L wet coating.
5.4 High-Shear Viscosity (HSV)—High-shear viscosity in this practice is a measure of the coatings resistance to flow on application by brush or roller, which is often referred to as brush-drag or rolling resistance respectively. This viscosity relates to the coatings ability to provide one-coat hiding...
SCOPE
1.1 This practice covers a popular industry protocol for the rheological characterization of waterborne architectural coatings using three commonly used rotational bench viscometers. Each viscometer operates in a different shear rate regime for determination of coating viscosity at low shear rate, mid shear rate, and at high shear rate respectively as defined herein. General guidelines are provided for predicting some coating performance properties from the viscosity measurements made. With appropriate correlations and subsequent modification of the performance guidelines, this practice has potential for characterization of other types of aqueous and non-aqueous coatings.
1.2 The values in common viscosity units (Krebs Units, KU and Poise, P) are to be regarded as standard.
1.3 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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Designation: D7394 − 13
Standard Practice for
Rheological Characterization of Architectural Coatings
1
using Three Rotational Bench Viscometers
This standard is issued under the fixed designation D7394; 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* D2805 Test Method for Hiding Power of Paints by Reflec-
tometry
1.1 This practice covers a popular industry protocol for the
D4040 Test Method for Rheological Properties of Paste
rheological characterization of waterborne architectural coat-
Printing and Vehicles by the Falling-Rod Viscometer
ings using three commonly used rotational bench viscometers.
D4062 Test Method for Leveling of Paints by Draw-Down
Each viscometer operates in a different shear rate regime for
Method
determination of coating viscosity at low shear rate, mid shear
D4287 Test Method for High-Shear Viscosity Using a Cone/
rate, and at high shear rate respectively as defined herein.
Plate Viscometer
General guidelines are provided for predicting some coating
D4400 Test Method for Sag Resistance of Paints Using a
performance properties from the viscosity measurements
made. With appropriate correlations and subsequent modifica- Multinotch Applicator
tion of the performance guidelines, this practice has potential D4414 Practice for Measurement of Wet Film Thickness by
for characterization of other types of aqueous and non-aqueous
Notch Gages
coatings. D4958 Test Method for Comparison of the Brush Drag of
Latex Paints
1.2 The values in common viscosity units (Krebs Units, KU
and Poise, P) are to be regarded as standard.
3. Terminology
1.3 This standard does not purport to address all of the
3.1 Definitions:
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.1.1 coating rheology, n—the viscosity profile obtained for
priate safety and health practices and determine the applica-
a fluid coating over a range of shear rates.
bility of regulatory limitations prior to use.
3.1.2 high-shear viscosity (HSV), n—the viscosity of a fluid
2. Referenced Documents
coating at high shear rate (typically measured at 10,000 or
-1
2
12,000 sec ), and for architectural coatings, it is often referred
2.1 ASTM Standards:
to as the “ICI” or “brush-drag” viscosity.
D562 Test Method for Consistency of Paints Measuring
KrebsUnit(KU)ViscosityUsingaStormer-TypeViscom-
3.1.3 leveling, n—the ability of a wet coating to flow out to
eter
a smooth dry film after application, thereby minimizing or
D869 TestMethodforEvaluatingDegreeofSettlingofPaint
eliminating coating surface irregularities that occur during
D1005 Test Method for Measurement of Dry-Film Thick-
brushing, rolling or spraying (see also Test Method D4062).
ness of Organic Coatings Using Micrometers
3.1.4 low-shear viscosity (LSV), n—the viscosity of a coat-
D1200 Test Method for Viscosity by Ford Viscosity Cup
ing fluid at low shear rate (typically in the range of 0.001 to
D2196 Test Methods for Rheological Properties of Non-
-1
1s ), often referred to as the “leveling viscosity” or inversely
Newtonian Materials by Rotational (Brookfield type)
Viscometer as the “suspension viscosity.”
3.1.5 mid-shear thickener effıciency (MSTE), n—the weight
1
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
of active thickener per unit volume of wet coating required to
Related Coatings, Materials, and Applications and is the direct responsibility of
give the target MSV, commonly expressed as lb active
Subcommittee D01.24 on Physical Properties of Liquid Paints and Paint Materials.
Current edition approved July 1, 2013. Published August 2013. Originally
thickener/100 gal wet coating (or in g/L units).
approved in 2008. Last previous edition approved in 2008 ad D7394 – 08. DOI:
10.1520/D7394-13.
3.1.6 mid-shear viscosity (MSV), n—the viscosity of a
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
coating fluid at medium shear rate (typically in the range of 10
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
-1
to 1000 s ), often referred to as the “consistency” or the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. “mixing viscosity.”
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7394 − 13
3.1.7 newtonian, n—a rheological term describing a fluid viscosity constant, meaningful comparisons
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7394 − 08 D7394 − 13
Standard Practice for
Rheological Characterization of Architectural Coatings
1
using Three Rotational Bench Viscometers
This standard is issued under the fixed designation D7394; 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 Scope*
1.1 This practice covers a popular industry protocol for the rheological characterization of waterborne architectural coatings
using three commonly used rotational bench viscometers. Each viscometer operates in a different shear rate regime for
determination of coating viscosity at low shear rate, mid shear rate, and at high shear rate respectively as defined herein. General
guidelines are provided for predicting some coating performance properties from the viscosity measurements made. With
appropriate correlations and subsequent modification of the performance guidelines, this practice has potential for characterization
of other types of aqueous and non-aqueous coatings.
1.2 The values stated in SI units common viscosity units (Krebs Units, KU and Poise, P) are to be regarded as standard.
1.3 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.
2. Referenced Documents
2
2.1 ASTM Standards:
D562 Test Method for Consistency of Paints Measuring Krebs Unit (KU) Viscosity Using a Stormer-Type Viscometer
D869 Test Method for Evaluating Degree of Settling of Paint
D1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using Micrometers
D1200 Test Method for Viscosity by Ford Viscosity Cup
D2196 Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational (Brookfield type) Viscometer
D2805 Test Method for Hiding Power of Paints by Reflectometry
D4040 Test Method for Rheological Properties of Paste Printing and Vehicles by the Falling-Rod Viscometer
D4062 Test Method for Leveling of Paints by Draw-Down Method
D4287 Test Method for High-Shear Viscosity Using a Cone/Plate Viscometer
D4400 Test Method for Sag Resistance of Paints Using a Multinotch Applicator
D4414 Practice for Measurement of Wet Film Thickness by Notch Gages
D4958 Test Method for Comparison of the Brush Drag of Latex Paints
3. Terminology
3.1 Definitions:
3.1.1 coating rheology, n—the viscosity profile obtained for a fluid coating over a range of shear rates.
3.1.2 high-shear viscosity (HSV), n—the viscosity of a fluid coating at high shear rate (typically measured at 10,000 or 12,000
-1
sec ), and for architectural coatings, it is often referred to as the “ICI” or “brush-drag” viscosity.
3.1.3 leveling, n—the ability of a wet coating to flow out to a smooth dry film after application, thereby minimizing or
eliminating coating surface irregularities that occur during brushing, rolling or spraying (see also Test Method D4062).
1
This practice is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.24 on Physical Properties of Liquid Paints &and Paint Materials.
Current edition approved Nov. 1, 2008July 1, 2013. Published December 2008August 2013. Originally approved in 2008. Last previous edition approved in 2008 ad D7394
– 08. DOI: 10.1520/D7394-08.10.1520/D7394-13.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D7394 − 13
3.1.4 low-shear viscosity (LSV), n—the viscosity of a coating fluid at low shear rate (typically in the range of 0.001 to
-1
1 s ), often referred to as the “leveling viscosity” or inversely as the “suspension viscosity.”
3.1.5 mid-shear thickener effıciency (MSTE), n—the weight of active thickener per unit volume of wet coating required to give
the target MSV, commonly expressed as lb ac
...
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