ASTM D6437-22

Standard Test Method for Polyurethane Raw Materials: Alkalinity in Low-Alkalinity Polyols (Determination of CPR Values of Polyols)

SIGNIFICANCE AND USE
5.1 This test method is suitable for quality control, as a specification test and for research. The urethane reaction between polyols and isocyanates to form polyurethane polymers is known to be sensitive to the presence of basic substances. This is particularly important in the preparation of polyurethane prepolymers which contain isocyanate groups that are known to react in the presence of trace amounts of basic substances. Since many polyether polyols are often made with strongly basic catalysts, it is important to have an analytical method capable of detecting small quantities of residual basic substances. This test method is capable of detecting ppm levels of base (as KOH).4
SCOPE
1.1 This test method covers measuring alkalinity in low-alkalinity (  
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.
Note 1: There is no known ISO equivalent to this standard.  
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-Mar-2022
• ICS: 83.040.01 - Raw materials for rubber and plastics in general
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

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: D6437 − 22
Standard Test Method for
Polyurethane Raw Materials: Alkalinity in Low-Alkalinity
1
Polyols (Determination of CPR Values of Polyols)
This standard is issued under the fixed designation D6437; 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* E2935 Practice for Evaluating Equivalence of Two Testing
Processes
1.1 This test method covers measuring alkalinity in low-
alkalinity (<0.002 meq/g basicity) polyols. This alkalinity is
3. Terminology
often expressed as CPR (controlled polymerization rate) of
3.1 Definitions:
polyether polyols. This test method is not applicable to
3.1.1 Terms used in this standard are defined in accordance
amine-based polyols.
with Terminology D883, unless otherwise specified. For terms
1.2 The values stated in SI units are to be regarded as
relating to precision and bias and associated issues, the terms
standard.
used in this standard are defined in accordance with Terminol-
1.3 This standard does not purport to address all of the
ogy E456.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 CPR—controlled polymerization rate is expressed as
priate safety, health, and environmental practices and deter-
basicity in milliequivalents per 30 kg of sample (meq/30 kg).
mine the applicability of regulatory limitations prior to use.
NOTE 1—There is no known ISO equivalent to this standard. 4. Summary of Test Method
1.4 This international standard was developed in accor-
4.1 This test method is a potentiometric titration for sample
dance with internationally recognized principles on standard-
basicity in methanol solvent. This test method uses a relatively
ization established in the Decision on Principles for the
large amount of sample and the titration is performed with
Development of International Standards, Guides and Recom-
dilute acid solution to determine trace quantities of basicity.
mendations issued by the World Trade Organization Technical
5. Significance and Use
Barriers to Trade (TBT) Committee.
5.1 This test method is suitable for quality control, as a
2. Referenced Documents
specification test and for research. The urethane reaction
2
2.1 ASTM Standards:
between polyols and isocyanates to form polyurethane poly-
D883 Terminology Relating to Plastics
mers is known to be sensitive to the presence of basic
E180 Practice for Determining the Precision of ASTM
substances. This is particularly important in the preparation of
Methods for Analysis and Testing of Industrial and Spe-
polyurethane prepolymers which contain isocyanate groups
3
cialty Chemicals (Withdrawn 2009)
that are known to react in the presence of trace amounts of
E456 Terminology Relating to Quality and Statistics
basic substances. Since many polyether polyols are often made
E691 Practice for Conducting an Interlaboratory Study to
with strongly basic catalysts, it is important to have an
Determine the Precision of a Test Method
analytical method capable of detecting small quantities of
residual basic substances. This test method is capable of
4
detecting ppm levels of base (as KOH).
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials -
6. Apparatus
Plastics and Elastomers.
Current edition approved March 15, 2022. Published March 2022. Originally
6.1 Potentiometric Automatic Titrator, capable of detecting
ɛ1
approved in 1999. Last previous edition approved in 2016 as D6437 - 05 (2016) .
multiple titration end points.
DOI: 10.1520/D6437-22.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.2 Autotitrator Buret, 5 mL (see Note 2).
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.
3 4
The last approved version of this historical standard is referenced on H.G. Scholten, J.G. Schuhman, R.E. TenHoor, Journal of Chemical Engineer-
www.astm.org. ing Data, 5, 1960, p. 396.
*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 ----------------------
D6437 − 22
5
6.3 Buret or Dosing Device, capable of dosing
...

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.
´1
Designation: D6437 − 05 (Reapproved 2016) D6437 − 22
Standard Test Method for
Polyurethane Raw Materials: Alkalinity in Low-Alkalinity
1
Polyols (Determination of CPR Values of Polyols)
This standard is issued under the fixed designation D6437; 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
ε NOTE—Reapproved with editorial changes in April 2016.
1. Scope Scope*
1.1 This test method covers measuring alkalinity in low-alkalinity (<0.002 meq/g basicity) polyols. This alkalinity is often
expressed as CPR (controlled polymerization rate) of polyether polyols. This test method is not applicable to amine-based polyols.
1.2 The values stated in SI units are to be regarded as the 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.
NOTE 1—There is no known ISO equivalent to this standard.
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:
D883 Terminology Relating to Plastics
E180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
3
(Withdrawn 2009)
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2935 Practice for Evaluating Equivalence of Two Testing Processes
3. Terminology
3.1 Definitions:
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics
and Elastomers.
Current edition approved April 1, 2016March 15, 2022. Published April 2016March 2022. Originally approved in 1999. Last previous edition approved in 20102016 as
ɛ1
D6437 - 05 (2010)(2016) . DOI: 10.1520/D6437-05R16E01.10.1520/D6437-22.
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.
3
The last approved version of this historical standard is referenced on www.astm.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
1

---------------------- Page: 1 ----------------------
D6437 − 22
3.1.1 The terminologyTerms used in this test method isstandard are defined in accordance with Terminology D883the standard
terminology defined in , 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 D883E456.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 CPR—controlled polymerization rate is expressed as basicity in milliequivalents per 30 kg of sample (meq/30 kg).
4. Summary of Test Method
4.1 This test method is a potentiometric titration for sample basicity in methanol solvent. This test method uses a relatively large
amount of sample and the titration is performed with dilute acid solution to determine trace quantities of basicity.
5. Significance and Use
5.1 This test method is suitable for quality control, as a specification test and for research. The urethane reaction between polyols
and isocyanates to form polyurethane polymers is known to be sensitive to the presence of basic substances. This is particularly
important in the preparation of polyurethane prepolymers which contain isocyanate groups that are known to react in the presence
of trace amounts of basic substances. Since many polyether polyols are often made with strongly basic catalysts, it is important
to have an analytical method capable of detecting small quantities of residual basic substances. This test method is capabl
...