ASTM D7394-18

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 quality control (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.
FIG. 1 Low Shear Viscosity (LSV)  
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 rela...
SCOPE
1.1 This practice describes 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, 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

• Status: Historical
• Publication Date: 31-May-2018
• ICS: 17.060 - Measurement of volume, mass, density, viscosity
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.24 - Physical Properties of Liquid Paints & Paint Materials

Standards Content (Sample)

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: D7394 − 18
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 D869 Test Method for Evaluating Degree of Settling of Paint
D1005 Test Method for Measurement of Dry-Film Thick-
1.1 This practice describes a popular industry protocol for
ness of Organic Coatings Using Micrometers
the rheological characterization of waterborne architectural
D1200 Test Method for Viscosity by Ford Viscosity Cup
coatings using three commonly used rotational bench viscom-
D2196 Test Methods for Rheological Properties of Non-
eters. Each viscometer operates in a different shear rate regime
Newtonian Materials by Rotational Viscometer
for determination of coating viscosity at low shear rate, mid
D2805 Test Method for Hiding Power of Paints by Reflec-
shear rate, and at high shear rate respectively as defined herein.
tometry
General guidelines are provided for predicting some coating
D4040 Test Method for Rheological Properties of Paste
performance properties from the viscosity measurements
Printing and Vehicles by the Falling-Rod Viscometer
made. With appropriate correlations and subsequent modifica-
D4062 Test Method for Leveling of Paints by Draw-Down
tion of the performance guidelines, this practice has potential
Method
for characterization of other types of aqueous and non-aqueous
D4287 Test Method for High-Shear Viscosity Using a Cone/
coatings.
Plate Viscometer
1.2 The values in common viscosity units (Krebs Units, KU
D4400 Test Method for Sag Resistance of Paints Using a
and Poise, P) are to be regarded as standard.
Multinotch Applicator
1.3 This standard does not purport to address all of the D4414 Practice for Measurement of Wet Film Thickness by
safety concerns, if any, associated with its use. It is the
Notch Gages
responsibility of the user of this standard to establish appro- D4958 Test Method for Comparison of the Brush Drag of
priate safety, health, and environmental practices and deter-
Latex Paints
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor-
3. Terminology
dance with internationally recognized principles on standard-
3.1 Definitions:
ization established in the Decision on Principles for the
3.1.1 coating rheology, n—the viscosity profile obtained for
Development of International Standards, Guides and Recom-
a fluid coating over a range of shear rates.
mendations issued by the World Trade Organization Technical
3.1.2 high-shear viscosity (HSV), n—the viscosity of a fluid
Barriers to Trade (TBT) Committee.
-1
coating at high shear rate (typically measured at 10,000 s or
-1
2. Referenced Documents
12,000 s ), and for architectural coatings, it is often referred to
2 as the “brush-drag” viscosity.
2.1 ASTM Standards:
D562 Test Method for Consistency of Paints Measuring
3.1.3 leveling, n—the ability of a wet coating to flow out to
Krebs Unit (KU) Viscosity Using a Stormer-Type Viscom-
a smooth dry film after application, thereby minimizing or
eter
eliminating coating surface irregularities that occur during
brushing, rolling or spraying (see also Test Method D4062).
3.1.4 low-shear viscosity (LSV), n—the viscosity of a coat-
1
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
-1
ing fluid at low shear rate (typically in the range of 0.001 s to
Related Coatings, Materials, and Applications and is the direct responsibility of
-1
Subcommittee D01.24 on Physical Properties of Liquid Paints and Paint Materials.
1 s ), often referred to as the “leveling viscosity” or inversely
Current edition approved June 1, 2018. Published June 2018. Originally
as the “suspension viscosity.”
approved in 2008. Last previous edition approved in 2017 as D7394 – 17. DOI:
10.1520/D7394-18.
3.1.5 mid-shear thickener effıciency (MSTE), n—the weight
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
of active thickener per unit volume of wet coating required to
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
give the target MSV, commonly expressed as lb active
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. thickener/100 gal wet coating (or in g/L units).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D7394 − 18
3.1.6 mid-s
...

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 − 17 D7394 − 18
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 coversdescribes 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 safety, health, and healthenvironmental 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.
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 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.
-1
3.1.2 high-shear viscosity (HSV), n—the viscosity of a fluid coating at high shear rate (typically measured at 10,000 s or
-1
12,000 s ), and for architectural coatings, it is often referred to as the “brush-drag” viscosity.
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 Feb. 1, 2017June 1, 2018. Published March 2017June 2018. Originally approved in 2008. Last previous edition approved in 2013 ad2017 as
D7394 – 13.17. DOI: 10.1520/D7394-17.10.1520/D7394-18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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

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D7394 − 18
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
3.1.4 low-shear viscosity (LSV), n—the viscosity of a coating
...