ASTM D4889-21

Standard Test Methods for Polyurethane Raw Materials: Determination of Viscosity of Crude or Modified Isocyanates

SIGNIFICANCE AND USE
4.1 These test methods can be used for research, quality control, or specification tests to characterize isocyanates used in polyurethane products.  
4.2 Viscosity measures the resistance of a fluid to uniform continuous flow without turbulence or other forces.  
4.3 Some isocyanates exhibit non-Newtonian behavior under certain conditions. Whenever possible, generate results for comparison under the same conditions, that is, the same spindle/speed combination for rotational viscosity and the same tube size for kinematic viscosity.
SCOPE
1.1 These test methods (A and B) determine the viscosity of crude or modified isocyanates. They are applicable to products derived from toluene diisocyanate, methylene di(phenylisocyanate), and polymeric (methylene phenylisocyanate) (see Note 1).
Note 1: Test method A includes a procedure for measuring dynamic viscosity using a rotational instrument. Test method B is a general procedure for kinematic viscosity of isocyanate.  
1.2 The values stated in SI units 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. For specific hazards statement, see Warning at the end of 5.1.
Note 2: Test Method A is equivalent to ISO 3219, Test Method B is equivalent to ISO 3104.  
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: Published
• Publication Date: 14-Jan-2021
• ICS: 83.040.30 - Auxiliary materials and additives for plastics
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Refers: ASTM D445-24 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Apr-2024
• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM D445-23 - Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• Effective Date: 01-Nov-2023
• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM D883-20 - Standard Terminology Relating to Plastics
• Effective Date: 01-Jan-2020
• Refers: ASTM D883-19c - Standard Terminology Relating to Plastics
• Effective Date: 01-Aug-2019
• Refers: ASTM D883-19a - Standard Terminology Relating to Plastics
• Effective Date: 15-Apr-2019
• Refers: ASTM D883-19 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2019
• Refers: ASTM D883-18a - Standard Terminology Relating to Plastics
• Effective Date: 01-Dec-2018
• Refers: ASTM D883-18 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2018
• Refers: ASTM E456-13A(2017)e3 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM E2935-17 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 01-Oct-2017
• Refers: ASTM E456-13A(2017)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Oct-2017
• Refers: ASTM D883-17 - Standard Terminology Relating to Plastics
• Effective Date: 15-Aug-2017

Overview

ASTM D4889-21 is an international standard specifying test methods for determining the viscosity of crude or modified isocyanates, which are essential raw materials in the manufacture of polyurethane products. Developed by ASTM International, this standard supports quality control, research, and specification compliance within industries utilizing isocyanates such as toluene diisocyanate, methylene di(phenylisocyanate), and their polymeric forms. The test methods outlined-namely, dynamic (rotational) and kinematic viscosity-are critical for characterizing material properties that impact processing and performance in polyurethane manufacturing.

Key Topics

• Viscosity Measurement: The standard defines procedures for testing both dynamic viscosity (using rotational viscometers) and kinematic viscosity (using glass capillary viscometers).
• Sample Handling and Preparation: Special precautions are emphasized because isocyanates react with atmospheric moisture, necessitating methods like using dry air or nitrogen blankets to maintain sample integrity.
• Test Conditions: Laboratory humidity and temperature control are required to prevent unwanted chemical reactions and ensure reproducibility.
• Instrument Calibration: Regular calibration with traceable standard fluids is essential for accurate viscosity measurement.
• Health and Safety: Clear warnings are provided due to the hazardous nature of isocyanates, which may cause respiratory and skin sensitization. Appropriate personal protective equipment (PPE) and safe handling practices must be established.
• Precision and Bias: While formal precision and bias statements are not available for all methods, users are guided by manufacturer-provided data and standard procedures to ensure reliable comparison.
• Reporting Requirements: Results must include detailed information regarding the instrument used, conditions, and viscosity values, supporting traceability for quality assurance.

Applications

ASTM D4889-21 plays a pivotal role in numerous applications across the polyurethane supply chain:

• Quality Control in Manufacturing: Ensures batch-to-batch consistency of isocyanate viscosity, directly affecting the processability and properties of polyurethane foams, elastomers, adhesives, and coatings.
• Material Characterization: Provides essential data for research and development, enabling manufacturers to select appropriate raw materials and optimize formulations for specific end-use requirements.
• Specification and Compliance Testing: Supports contractual and regulatory requirements in procurement and supply agreements.
• Process Optimization: Reliable viscosity data allow for adjustments in processing conditions, such as mixing and pumping parameters, reducing waste and improving product quality.

Related Standards

Several referenced standards offer complementary procedures and terminologies, ensuring harmonization and broader applicability:

• ASTM D445: Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
• ASTM D446: Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers
• ASTM D883: Terminology Relating to Plastics
• ASTM E2251: Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
• ASTM E2935: Practice for Conducting Equivalence Tests for Comparing Testing Processes
• ISO 3104: Determination of Kinematic Viscosity and Calculation of Dynamic Viscosity
• ISO 3219: Determination of Viscosity Using a Rotational Viscometer with Defined Shear Rate

These related methods provide a comprehensive framework for viscosity determination, facilitating consistency and comparability of results across the polyurethane industry.

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Keywords: ASTM D4889-21, polyurethane raw materials, isocyanate viscosity, dynamic viscosity, kinematic viscosity, quality control, polyurethane manufacturing, rotational viscometer, glass capillary viscometer, material characterization, isocyanate testing.

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:D4889 −21
Standard Test Methods for
Polyurethane Raw Materials: Determination of Viscosity of
Crude or Modified Isocyanates
This standard is issued under the fixed designation D4889; 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* D446 Specifications and Operating Instructions for Glass
Capillary Kinematic Viscometers
1.1 These test methods (Aand B) determine the viscosity of
D883 Terminology Relating to Plastics
crude or modified isocyanates. They are applicable to products
E456 Terminology Relating to Quality and Statistics
derived from toluene diisocyanate, methylene
E2251 Specification for Liquid-in-Glass ASTM Thermom-
di(phenylisocyanate), and polymeric (methylene phenylisocya-
eters with Low-Hazard Precision Liquids
nate) (see Note 1).
E2935 Practice for Conducting Equivalence Tests for Com-
NOTE 1—Test method A includes a procedure for measuring dynamic
paring Testing Processes
viscosity using a rotational instrument. Test method B is a general
2.2 ISO Standards:
procedure for kinematic viscosity of isocyanate.
ISO 3104 Petroleum Products—Transparent and Opaque
1.2 The values stated in SI units are to be regarded as
Liquids—Determination of Kinematic Viscosity and Cal-
standard.
culation of Dynamic Viscosity
1.3 This standard does not purport to address all of the
ISO 3219 Plastics—Polymers/Resins in the Liquid State or
safety concerns, if any, associated with its use. It is the
as Emulsions or Dispersions—Determination of Viscosity
responsibility of the user of this standard to establish appro-
Using a Rotational Viscometer with Defined Shear Rate
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 3. Terminology
For specific hazards statement, see Warning at the end of 5.1.
3.1 Terms used in this standard are defined in accordance
with Terminology D883, unless otherwise specified. For terms
NOTE 2—Test Method A is equivalent to ISO 3219, Test Method B is
equivalent to ISO 3104.
relating to precision and bias and associated issues, the terms
used in this standard are defined in accordance with Terminol-
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard- ogy E456.
ization established in the Decision on Principles for the
4. Significance and Use
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.1 These test methods can be used for research, quality
Barriers to Trade (TBT) Committee.
control, or specification tests to characterize isocyanates used
in polyurethane products.
2. Referenced Documents
4.2 Viscosity measures the resistance of a fluid to uniform
2.1 ASTM Standards:
continuous flow without turbulence or other forces.
D445 Test Method for Kinematic Viscosity of Transparent
4.3 Some isocyanates exhibit non-Newtonian behavior un-
and Opaque Liquids (and Calculation of Dynamic Viscos-
der certain conditions. Whenever possible, generate results for
ity)
comparison under the same conditions, that is, the same
spindle/speed combination for rotational viscosity and the
same tube size for kinematic viscosity.
These test methods are under the jurisdiction of ASTM Committee D20 on
Plastics and are the direct responsibility of Subcommittee D20.22 on Cellular
5. Sampling
Materials - Plastics and Elastomers.
Current edition approved Jan. 15, 2021. Published January 2021. Originally
5.1 Since organic isocyanates react with atmospheric
approved in 1988. Last previous edition approved in 2015 as D4889 - 15. DOI:
moisture, take special precautions in sampling. Usual sampling
10.1520/D4889-21.
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 Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
D4889−21
methods, even when conducted rapidly, can cause contamina- temperature distribution as well as the presence of air bubbles
tion of the sample with insoluble urea. Therefore, blanket the andtracesofextraneousmaterialaretobeavoided.Thesample
sample with dry air or nitrogen at all times. (Warning— must be thoroughly mixed and the temperature measured at
Diisocyanates are eye, skin and respiratory irritants at concen- several locations in the sample vessel before determining the
trations above the occupational exposure limit (TLV or PEL). viscosity.
Diisocyanates can cause skin and respiratory sensitization
(asthma)insomepeople.Oncesensitized,itisessentialtolimit 11. Preparation of Apparatus
further exposure to diisocyanates. Use a combination of
11.1 Follow the manufacturer’s instructions to set up the
engineering controls and personal protective equipment, in-
instrument and ensure that the viscometer is level.
cluding respiratory, skin and eye protection, to prevent over-
exposure to diisocyanates. Consult the product suppliers’
12. Choice of Temperature
Safety Data Sheet (SDS) for more detailed information about
12.1 Samples that are liquid and have a viscosity of less
potential health effects and other specific safety and handling
than 100 000 mPa·s(cP) at 25°C are to be measured at 25°C.
instructions for the product.)
12.2 In cases of interlaboratory studies and higher viscosity
6. Test Conditions
samples, all parties are to agree upon a set measurement
6.1 Since isocyanates react with moisture, keep laboratory temperature.
humidity low, preferably about 50 % relative humidity. See
Warning in 5.1. 13. Choice of Spindle and Rotational Speed
13.1 Rotational Viscometers offer a variety of spindle size
TEST METHOD A—ROTATIONAL VISCOSITY
and rotational speeds. In the case of non-Newtonian liquids,
changing these factors will cause variation in the results
7. Summary of Test Method
obtained. In general, the following recommendations provide
7.1 The viscosity is measured by determining the torque on
guidance for choosing the spindle size and speed to be used for
a spindle rotating at constant speed in the liquid sample which
a specific sample.
is adjusted to 25 6 0.1°C. Generation of comparative data
13.1.1 The combination chosen shall generate a torque
using this method requires agreement on the speed, spindle,
valuebetween15and90%offullscale,orthatspecifiedbythe
temperature, time of rotation and torque range of the instru-
instrument manufacturer.
ment used.
13.1.1.1 If more than one speed/spindle combination will
fulfill the requirement of 13.1.1, the combination with the
8. Apparatus
higher speed will provide higher accuracy and the combination
8.1 Constant-Temperature Bath, capable of maintaining a
with the lower speed will minimize certain types of non-
temperature of 25 6 0.1°C is to be used. Water, water and
Newtonian behavior.
glycerin, or oil is used as the heating medium and the bath is
13.1.1.2 There must be agreement between the testing
to be provided with heating, circulating, and thermostatting
laboratory and the submitter on the spindle/speed selection.
devices.
8.2 Bath and Sample Thermometers, graduated in 0.1°C
14. Procedure
subdivisions and standardized for the range of use to the
14.1 Using the smallest container recommended by the
nearest 0.01°C. ASTM Saybolt Viscosity Thermometers hav-
manufacturer, place sufficient sample to cover the immersion
ing ranges from 19 to 27°C and 49 to 57°C, as specified, and
mark on the viscometer spindle. Cover the container and
conforming to the requirements for Thermometers S117C and
immerse it to the sample level in a constant temperature bath.
S64C, respectively, as prescribed in Specification E2251 are
Stir occasionally without trapping air bubbles. Check the
recommended. Any other thermometric device of equal or
temperature at several different locations in the container to
better accuracy is also acceptable.
make sure uniformity has been achieved.
8.3 Rotational Viscometer, capable of user defined speed
14.2 After the desired temperature has been observed
and spindle combinations. An instrument that is capable of
throughout the sample for 10 min, immerse the viscometer
providingtheshearrateisrecommended.Thecalibrationofthe
spindle (and the guard when recommended by the manufac-
instrument is to be checked periodically by measuring the
turer) into a sample to the immersion line marked on the
viscosity of NIST traceable standard fluids.
spindle. Exercise caution to avoid air bubbles gathering under
the spindle during immersion. If bubbles are observed, detach
9. Solvent
the spindle, keeping it in the sample, and stir until the bubbles
9.1 Cleaning Solvent—dichloromethane or acetone, reagent
are released. Reattach the spindle.
grade. Any solvent in which the isocyanate is completely
14.3 Follow the manufacturer’s instructions to measure the
miscible is acceptable.
viscosity for the sample using a 15 second rotation time.
10. Preparation of Sample
14.4 After the analysis, spindles are cleaned with a solvent
10.1 The preparation of a homogeneous sample is of pri- appropriate for the isocyanate and equipment used, for
mary importance in viscosity measurements. A non-uniform example, dichloromethane or acetone.
D4889−21
15. Calculation 19.4 Glass Capillary Viscometer, calibrated by the manu-
facturer.
15.1 Multiply the reading by the factor provided by the
manufacture for the speed/spindle combination used to convert 19.5 Timing Device, capable of reading to the nearest 0.1 s
the instrument reading to the viscosity in mPa.s (cP). Most or better, with an accuracy of 60.07 % of the reading when
instruments automatically perform this calculation. tested over the intervals of 200 and 900 s.
16. Report 20. Solvent
16.1 Report the following information: 20.1 Cleaning So
...

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: D4889 − 15 D4889 − 21
Standard Test Methods for
Polyurethane Raw Materials: Determination of Viscosity of
Crude or Modified Isocyanates
This standard is issued under the fixed designation D4889; 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*
1.1 These test methods (A and B) determine the viscosity of crude or modified isocyanates. They are applicable to products derived
from toluene diisocyanate, methylene di(phenylisocyanate), and polymeric (methylene phenylisocyanate) (see Note 1).
NOTE 1—Test method A includes a procedure for measuring dynamic viscosity using a rotational instrument. Test method B is simply a reference to a
a general procedure for measuring kinematic viscosity,viscosity D445. of isocyanate.
1.2 The values stated in SI units 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. For specific hazards statement, see Warning at the end of 5.1.
NOTE 2—This standard is equivalent to ISO 3219 and ISO 3104.
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. For specific hazards statement, see Warning at the end of 5.1.
NOTE 2—Test Method A is equivalent to ISO 3219, Test Method B is equivalent to ISO 3104.
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
2.1 ASTM Standards:
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
D446 Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers
D883 Terminology Relating to Plastics
These test methods are under the jurisdiction of ASTM Committee D20 on Plastics and are the direct responsibility of Subcommittee D20.22 on Cellular Materials -
Plastics and Elastomers.
Current edition approved May 1, 2015Jan. 15, 2021. Published June 2015January 2021. Originally approved in 1988. Last previous edition approved in 20112015 as
D4889 - 04D4889 - 15.(2011). DOI: 10.1520/D4889-15.10.1520/D4889-21.
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
D4889 − 21
E456 Terminology Relating to Quality and Statistics
E2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
E2935 Practice for Conducting Equivalence Tests for Comparing Testing Processes
2.2 ISO Standards:
ISO 3104 Petroleum Products—Transparent and Opaque Liquids—Determination of Kinematic Viscosity and Calculation of
Dynamic Viscosity
ISO 3219 Plastics—Polymers/Resins in the Liquid State or as Emulsions or Dispersions—Determination of Viscosity Using a
Rotational Viscometer with Defined Shear Rate
3. Terminology
3.1 Definitions—For definitions of terms used in these test methods see Terms used in this standard are defined in accordance with
Terminology D883, unless otherwise specified. For terms relating to precision and bias and associated issues, the terms used in
this standard are defined in accordance with Terminology E456.
4. Significance and Use
4.1 These test methods can be used for research, quality control, or specification tests to characterize isocyanates used in
polyurethane products.
4.2 Viscosity measures the resistance of a fluid to uniform continuous flow without turbulence or other forces.
4.3 Some isocyanates exhibit non-Newtonian behavior under certain conditions. Whenever possible, generate results for
comparison under the same conditions, that is, the same spindle/speed combination for rotational viscosity and the same tube size
for kinematic viscosity.
5. Sampling
5.1 Since organic isocyanates react with atmospheric moisture, take special precautions in sampling. Usual sampling methods,
even when conducted rapidly, can cause contamination of the sample with insoluble urea. Therefore, blanket the sample with dry
air or nitrogen at all times. (Warning—Diisocyanates are eye, skin and respiratory irritants at concentrations above the
occupational exposure limit (TLV or PEL). Diisocyanates can cause skin and respiratory sensitization (asthma) in some people.
Once sensitized, it is essential to limit further exposure to diisocyanates. Use a combination of engineering controls and personal
protective equipment, including respiratory, skin and eye protection, to prevent over-exposure to diisocyanates. Consult the product
suppliers’ Safety Data Sheet (SDS) for more detailed information about potential health effects and other specific safety and
handling instructions for the product.)
6. Test Conditions
6.1 Since isocyanates react with moisture, keep laboratory humidity low, preferably about 50 % relative humidity. See Warning
in 5.1.
TEST METHOD A—ROTATIONAL VISCOSITY
7. Summary of Test Method
7.1 The viscosity is measured by determining the torque on a spindle rotating at constant speed in the liquid sample which is
adjusted to 25 6 0.1°C. Generation of comparative data using this method requires agreement on the speed, spindle, temperature,
time of rotation and torque range of the instrument used.
8. Apparatus
8.1 Constant-Temperature Bath, capable of maintaining a temperature of 25 6 0.1°C is to be used. Water, water and glycerin, or
oil is used as the heating medium and the bath is to be provided with heating, circulating, and thermostatting devices.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
D4889 − 21
8.2 Bath and Sample Thermometers, graduated in 0.1°C subdivisions and standardized for the range of use to the nearest 0.01°C.
ASTM Saybolt Viscosity Thermometers having ranges from 19 to 27°C and 49 to 57°C, as specified, and conforming to the
requirements for Thermometers S117C and S64C, respectively, as prescribed in Specification E2251 are recommended. Any other
thermometric device of equal or better accuracy is also acceptable.
8.3 Rotational Viscometer, capable of user defined speed and spindle combinations. An instrument that is capable of providing the
shear rate is recommended. The calibration of the instrument is to be checked periodically by measuring the viscosity of NIST
traceable standard fluids.
9. Solvent
9.1 Cleaning Solvent—dichloromethane or acetone, reagent grade. Any solvent in which the isocyanate is completely miscible is
acceptable.
10. Preparation of Sample
10.1 The preparation of a homogeneous sample is of primary importance in viscosity measurements. A non-uniform temperature
distribution as well as the presence of air bubbles and traces of extraneous material are to be avoided. The sample must be
thoroughly mixed and the temperature measured at several locations in the sample vessel before determining the viscosity.
11. Preparation of Apparatus
11.1 Follow the manufacturer’s instructions to set up the instrument and ensure that the viscometer is level.
12. Choice of Temperature
12.1 Samples that are liquid and have a viscosity of less than 100 000 mPa·s(cP) at 25°C are to be measured at 25°C.
12.2 In cases of interlaboratory studies and higher viscosity samples, all parties are to agree upon a set measurement temperature.
13. Choice of Spindle and Rotational Speed
13.1 Rotational Viscometers offer a variety of spindle size and rotational speeds. In the case of non-Newtonian liquids, changing
these factors will cause variation in the results obtained. In general, the following recommendations provide guidance for choosing
the spindle size and speed to be used for a specific sample.
13.1.1 The combination chosen shall generate a torque value between 15 and 90% of full scale, or that specified by the instrument
manufacturer.
13.1.1.1 If more than one speed/spindle combination will fulfill the requirement of 13.1.1, the combination with the higher speed
will provide higher accuracy and the combination with the lower speed will minimize certain types of non-Newtonian behavior.
13.1.1.2 There must be agreement between the testing laboratory and the submitter on the spindle/speed selection.
14. Procedure
14.1 Using the smallest container recommended by the manufacturer, place sufficient sample to cover the immersion mark on the
viscometer spindle. Cover the container and immerse it to the sample level in a constant temperature bath. Stir occasionally without
trapping air bubbles. Check the temperature at several different locations in the container to make sure uniformity has been
achieved.
14.2 After the desired temperature has been observed throughout the sample for 10 min, immerse the viscometer spindle (and the
guard when recommended by the manufacturer) into a sample to the immersion line marked on the spindle. Exercise caution to
avoid air bubbles gathering under the spindle during immersion. If bubbles are observed, detach the spindle, keeping it in the
sample, and stir until the bubbles are released. Reattach the spindle.
D4889 − 21
14.3 Follow the manufacturer’s instructions to measure the viscosity for the sample using a 15 second rotation time.
14.4 After the analysis, spindles are cleaned with a solvent appropriate for the isocyanate and equipment used, for example,
dichloromethane or acetone.
15. Calculation
15.1 Multiply the reading by the factor provided by the manufacture for the speed/spindle combination used to convert the
instrument reading to the viscosity in mPa.s (cP). Most instruments automatically perform this calculation.
16. Report
16.1 Report the following information:
16.1.1 Temperature of test,
16.1.2 Model of viscometer,
16.1.3 Speed of rotation,
16.1.4 Spindle number, and
16.1.5 Viscosity in millipascal seconds (centipoises) [mPa—s(cP)].
17. Precision and Bias
17.1 Precision—Attempts to develop a precision and bias statement for this test method have not been successful; however, the
precision is expected to be equivalent to that reported by the instrument manufacturer. For this reason, data on precision and bias
cannot be given. Bec
...