ASTM D4663-20

Standard Test Method for Polyurethane Raw Materials: Determination of Hydrolyzable Chlorine of Isocyanates

SIGNIFICANCE AND USE
5.1 This test method can be used for research or for quality control to characterize toluene diisocyanates. Hydrolyzable chlorine correlates with performance in some polyurethane systems.
SCOPE
1.1 This test method determines the hydrolyzable chlorine content of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, or mixtures of the two. It is acceptable to apply this test method to other isocyanates of suitable solubility. (See Note 1.) The main sources of hydrolyzable chlorine in the isocyanates are carbamoyl chloride and dissolved phosgene. Both of these compounds react with alcohols and water, forming ureas, carbamates, carbon dioxide, and hydrochloric acid. (See Note 2.)  
1.2 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: It is possible that this test method is applicable to crude polymeric isocyanates. However, the precision with crude polymeric isocyanates has not been established.
Note 2: This standard is identical to ISO 15028.  
1.3 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: 31-Mar-2020
• ICS: 83.080.10 - Thermosetting materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D4663-15 - Standard Test Method for Polyurethane Raw Materials: Determination of Hydrolyzable Chlorine of Isocyanates
• Effective Date: 01-Apr-2020
• 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 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)e1 - 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)e3 - 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
• Refers: ASTM E2935-16 - Standard Practice for Conducting Equivalence Testing in Laboratory Applications
• Effective Date: 15-Nov-2016

Overview

ASTM D4663-20 is the standard test method for determining hydrolyzable chlorine in polyurethane raw materials, specifically isocyanates such as toluene-2,4-diisocyanate (TDI) and toluene-2,6-diisocyanate (TDI), as well as mixtures of these. Developed by ASTM International, this test is vital for both research and quality control in the production of polyurethanes. The presence of hydrolyzable chlorine can directly influence the performance of polyurethane systems, making accurate measurement essential for product consistency and compliance.

Key Topics

• Scope: This method applies to toluene diisocyanates and can be extended to other isocyanates that are suitably soluble. It also may be applicable to crude polymeric isocyanates, though its precision in this context has not been fully established.
• Significance: The test measures low-level chlorine-containing compounds such as carbamoyl chloride and dissolved phosgene. These compounds can react with alcohols and water, forming ureas, carbamates, carbon dioxide, and hydrochloric acid, impacting the material’s final properties.
• Test Method Summary:
  • Hydrolyzable chlorine reacts with methanol, liberating hydrochloric acid.
  • The resulting titratable chlorides are measured potentiometrically using a standard silver nitrate solution.
• Interference: Substances like thiocyanate, cyanide, sulfide, bromide, iodide, or agents capable of reacting or reducing silver ions can interfere with the determination, affecting results.
• Safety: Isocyanates are hazardous chemicals; proper safety, health, and environmental precautions must be observed, including personal protective equipment and controlling exposure to prevent sensitization.
• Standardization: ASTM D4663-20 is aligned with internationally recognized standardization principles and is identical to ISO 15028.

Applications

ASTM D4663-20 is essential in several sectors involving polyurethanes and isocyanate chemistry:

• Quality Control: Ensures the hydrolyzable chlorine content is within specified limits, maintaining product quality and performance in polyurethane systems.
• Research and Development: Assists in characterizing raw materials and improving formulations for better performance and compliance.
• Manufacturing of Polyurethanes: Helps manufacturers monitor and control the purity and reactivity of isocyanate raw materials, influencing the end-use properties of flexible foams, coatings, adhesives, elastomers, and other polyurethane products.
• Regulatory Compliance: Supports adherence to industry and international standards regarding chemical composition and safety, promoting consistency in cross-border trade and product acceptance.

Related Standards

For organizations and laboratories working with isocyanates and polyurethane raw materials, familiarity with related standards enhances consistency and technical reliability:

• ISO 15028: Plastics - Aromatic Isocyanates for Use in the Production of Polyurethanes - Determination of Hydrolysable Chlorine (identical to ASTM D4663-20).
• ASTM D883: Terminology Relating to Plastics.
• ASTM D1193: Specifications for Reagent Water.
• ASTM E456: Terminology Relating to Quality and Statistics.
• ASTM E2935: Practice for Conducting Equivalence Testing in Laboratory Applications.

Keywords: polyurethane raw materials, hydrolyzable chlorine, isocyanates, toluene diisocyanate, ASTM D4663-20, quality control, titration, standard test method

Adhering to ASTM D4663-20 supports best practices for the accurate determination of hydrolyzable chlorine in isocyanate raw materials, ensuring high-quality polyurethane production and regulatory compliance across the industry.

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: D4663 − 20
Standard Test Method for
Polyurethane Raw Materials: Determination of Hydrolyzable
Chlorine of Isocyanates
This standard is issued under the fixed designation D4663; 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* Laboratory Applications
2.2 ISO Standards:
1.1 This test method determines the hydrolyzable chlorine
ISO 15028 Plastics—Aromatic Isocyanates for Use in the
content of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate,
Production of Polyurethanes—Determination of Hydroly-
ormixturesofthetwo.Itisacceptabletoapplythistestmethod
sable Chlorine
to other isocyanates of suitable solubility. (See Note 1.) The
main sources of hydrolyzable chlorine in the isocyanates are
3. Terminology
carbamoyl chloride and dissolved phosgene. Both of these
compounds react with alcohols and water, forming ureas, 3.1 Definitions—Terms used in this standard are defined in
accordance with Terminology D883, unless otherwise speci-
carbamates, carbon dioxide, and hydrochloric acid. (See Note
2.) fied. For terms relating to precision and bias and associated
issues,thetermsusedinthisstandardaredefinedinaccordance
1.2 This standard does not purport to address all of the
with Terminology E456.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.2 Definitions of Terms Specific to This Standard:
priate safety, health, and environmental practices and deter-
3.2.1 hydrolyzable chloride—the low-level chlorine-
mine the applicability of regulatory limitations prior to use. containing components of the isocyanate, such as carbamoyl
chlorides, which react with water or alcohol to form HCl.
NOTE 1—It is possible that this test method is applicable to crude
polymeric isocyanates. However, the precision with crude polymeric
4. Summary of Test Method
isocyanates has not been established.
NOTE 2—This standard is identical to ISO 15028.
4.1 The hydrolyzable chlorine reacts with methanol, liber-
1.3 This international standard was developed in accor-
ating hydrochloric acid. The titratable chlorides are then
dance with internationally recognized principles on standard-
determined potentiometrically using a standard silver nitrate
ization established in the Decision on Principles for the
solution.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical 5. Significance and Use
Barriers to Trade (TBT) Committee.
5.1 This test method can be used for research or for quality
control to characterize toluene diisocyanates. Hydrolyzable
2. Referenced Document
chlorine correlates with performance in some polyurethane
2.1 ASTM Standards:
systems.
D883 Terminology Relating to Plastics
6. Interferences
D1193 Specification for Reagent Water
E456 Terminology Relating to Quality and Statistics
6.1 Thiocyanate, cyanide, sulfide, bromide, iodide, or other
E2935 Practice for Conducting Equivalence Testing in
substances capable of reacting with silver ions, as well as
substances capable of reducing silver ions in acid solution, will
interfere with the determination.
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials -
7. Apparatus
Plastics and Elastomers.
Current edition approved April 1, 2020. Published April 2020. Originally
7.1 Weighing Bottle, or any device capable of weighing a
approved in 1987. Last previous edition approved in 2015 as D4663 - 15. DOI:
liquid by difference to the nearest 0.1 g.
10.1520/D4663-20.
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
D4663 − 20
7.2 Hot Plate, with magnetic stirrer. 400-mL beaker (Note 3).Add 50 mL of methanol and stir. Stir
continuouslywhilethereactionstartsatwhichpointthebeaker
7.3 Potentiometric Titrator, or pH meter.
will become warm and crystals may form on the sides of the
7.4 Combination Silver Billet Electrode.
beaker (Note 4). Fill the beaker half-full with water (Note 5)
and boil gently for 30 min.
8. Reagents and Materials
NOTE3—Ifthehydrolyzablechlorinecontentisexpectedtobelessthan
8.1 Purity of Reagents—Use reagent grade chemicals in all
0.01 %, use 18 to 22 g of sample.
tests.Unlessotherwiseindicated,itisintendedthatallreagents
NOTE 4—Some isocyanates will not react readily, and slight warming
conform to the specifications of the Committee on Analytical
may be necessary to initiate reaction. Other isocyanates may react, as
Reagents of the American Chemical Society where such indicated by warming of reactants, but may not form crystals.
NOTE 5—Add the water quickly to keep the reactants from solidifying
specifications are available. Other grades may be used, pro-
and to minimize the loss of HCl.
vided it is first ascertained that the reagent is of sufficiently
11.2 Wash the sides of the beaker with water and remove
high purity to permit its use without lessening t
...

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: D4663 − 15 D4663 − 20
Standard Test Method for
Polyurethane Raw Materials: Determination of Hydrolyzable
Chlorine of Isocyanates
This standard is issued under the fixed designation D4663; 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 This test method determines the hydrolyzable chlorine content of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, or
mixtures of the two. It is acceptable to apply this test method to other isocyanates of suitable solubility. (See Note 1.) The main
sources of hydrolyzable chlorine in the isocyanates are carbamoyl chloride and dissolved phosgene. Both of these compounds react
with alcohols and water, forming ureas, carbamates, carbon dioxide, and hydrochloric acid. (See Note 2.)
1.2 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.
NOTE 1—It is possible that this test method is applicable to crude polymeric isocyanates. However, the precision with crude polymeric isocyanates has
not been established.
NOTE 2—This standard is identical to ISO 15028.
1.2 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—It is possible that this test method is applicable to crude polymeric isocyanates. However, the precision with crude polymeric isocyanates has
not been established.
NOTE 2—This standard is identical to ISO 15028.
1.3 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 Document
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D1193 Specification for Reagent Water
E456 Terminology Relating to Quality and Statistics
E2935 Practice for Conducting Equivalence Testing in Laboratory Applications
2.2 ISO Standards:
ISO 15028 Plastics—Aromatic Isocyanates for Use in the Production of Polyurethanes—Determination of Hydrolysable
Chlorine
3. Terminology
3.1 Definitions—For definitions of terms Terms used in this test method see 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.
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 May 1, 2015April 1, 2020. Published June 2015April 2020. Originally approved in 1987. Last previous edition approved in 20102015 as
D4663 - 10.D4663 - 15. DOI: 10.1520/D4663-15.10.1520/D4663-20.
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.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 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
D4663 − 20
3.2 Definitions of Terms Specific to This Standard:
3.2.1 hydrolyzable chloride—the low level low-level chlorine-containing components of the isocyanate, such as carbamoyl
chlorides, which react with water or alcohol to form HCl.
4. Summary of Test Method
4.1 The hydrolyzable chlorine reacts with methanol, liberating hydrochloric acid. The titratable chlorides are then determined
potentiometrically using a standard silver nitrate solution.
5. Significance and Use
5.1 This test method can be used for research or for quality control to characterize toluene diisocyanates. Hydrolyzable chlorine
correlates with performance in some polyurethane systems.
6. Interferences
6.1 Thiocyanate, cyanide, sulfide, bromide, iodide, or other substances capable of reacting with silver ions, as well as substances
capable of reducing silver ions in acid solution, will interfere with the determination.
7. Apparatus
7.1 Weighing Bottle, or any device capable of weighing a liquid by difference to the nearest 0.1 g.
7.2 Hot Plate, with magnetic stirrer.
7.3 Potentiometric Titrator, or pH meter.
7.4 Combination Silver Billet Electrode.
8. Reagents and Materials
8.1 Purity of Reagents—Use reagent grade chemicals in all tests. Unless otherwise indicated, it is intended that all reagents
conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
8.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by
Type I of Specification D1193.
8.3 Concentrated Nitric Acid (HNO sp gr 1.42).
8.4 Methanol.
8.5 Silver Nitrate Standard Solution (0.01 N)—Standardize with standard hydrochloric acid, either gravimetrically or
potentiometrically, frequently enough to detect changes of 0.0005 N.
9. Sampling
9.1 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—Di
...