ASTM D1786-21

Standard Specification for Toluene Diisocyanate

ABSTRACT
This specification covers toluene diisocyanate used as an ingredient in the production of polyurethane cellular materials. The three classes of toluene diisocyanate covered in this specification are based on isomer ratio, and the three types are based on acidity and hydrolyzable chloride. Materials shall be tested and the individual grades shall conform to specified values of isomer ratio, purity, APHA color, and total chlorine.
SCOPE
1.1 This specification covers toluene diisocyanate used as an ingredient in the production of polyurethane materials.  
Note 1: The properties included in this specification are those required to characterize toluene diisocyanate. Other requirements are possible and will be added as the necessary test methods become available.  
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 2: There is no known ISO equivalent to this standard.  
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: 30-Jun-2021
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• 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 D4663-20 - Standard Test Method for Polyurethane Raw Materials: Determination of Hydrolyzable Chlorine of Isocyanates
• Effective Date: 01-Apr-2020
• Refers: ASTM D883-20 - Standard Terminology Relating to Plastics
• Effective Date: 01-Jan-2020
• Refers: ASTM D5155-19 - Standard Test Methods for Polyurethane Raw Materials: Determination of the Isocyanate Content of Aromatic Isocyanates
• Effective Date: 01-Aug-2019
• Refers: ASTM D4877-19 - Standard Test Method for Polyurethane Raw Materials: Determination of APHA Color in Isocyanates
• Effective Date: 01-Aug-2019
• 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 D883-17 - Standard Terminology Relating to Plastics
• Effective Date: 15-Aug-2017
• Refers: ASTM D4663-15 - Standard Test Method for Polyurethane Raw Materials: Determination of Hydrolyzable Chlorine of Isocyanates
• Effective Date: 01-May-2015
• Refers: ASTM D5155-14 - Standard Test Methods for Polyurethane Raw Materials: Determination of the Isocyanate Content of Aromatic Isocyanates
• Effective Date: 01-Nov-2014
• Refers: ASTM D5155-14e1 - Standard Test Methods for Polyurethane Raw Materials: Determination of the Isocyanate Content of Aromatic Isocyanates
• Effective Date: 01-Nov-2014

Overview

ASTM D1786-21: Standard Specification for Toluene Diisocyanate defines the requirements for toluene diisocyanate (TDI) used as a key ingredient in the production of polyurethane materials, especially cellular polyurethane. TDI is an essential industrial chemical in the plastics industry due to its role in forming flexible and rigid foams, elastomers, and coatings.

This international ASTM standard provides clear classification and specification criteria for various classes and types of TDI based on isomer ratio, acidity, and hydrolyzable chloride content. It also includes requirements for purity, APHA color, and total chlorine, ensuring that TDI meets the quality standards necessary for safe and effective use in manufacturing processes.

Key Topics

• Classification and Types

  • Covers three classes of toluene diisocyanate, based on isomer ratios.
  • Each class is subdivided into three types determined by acidity and hydrolyzable chloride levels.

• Specification Requirements

  • Isomer ratio percentage is specified per class (e.g., 100%, 80%, 65% of the 2,4 isomer).
  • Minimum purity requirement of 99.5% for all classes.
  • Maximum APHA color value set at 50 to ensure suitability for sensitive applications.
  • Total chlorine limit of 0.2% as a standard quality threshold.
  • Types I (A), II (B), and III (C) set distinct acidity and hydrolyzable chloride limits, aligning with different end-use requirements.

• Testing and Quality Assurance

  • Testing methods include procedures for determining isomer content, total/hydrolyzable chlorine, acidity, and color.
  • Materials must conform to prescribed values through tests conducted according to referenced ASTM methods.

• Packaging and Labeling

  • Product packaging must comply with Department of Transportation and regulatory guidelines.
  • Shipping containers must include proper hazard labeling, material identification, quantity, and manufacturer’s emergency contact information.

Applications

Toluene diisocyanate (TDI) is widely used in the manufacture of polyurethane products such as:

• Flexible polyurethanes: Used in automotive seats, furniture cushioning, and bedding materials.
• Rigid foams: Key in insulation panels and construction materials.
• Elastomers and coatings: Applies to adhesives, sealants, paints, and surface coatings for industrial and consumer products.

By providing standardized quality and purity parameters, ASTM D1786-21 ensures TDI's consistent performance in demanding applications, supporting product safety, regulatory compliance, and efficient supply chain management in the polyurethane industry.

Related Standards

• ASTM D883: Terminology Relating to Plastics
• ASTM D4660: Test Methods for Determination of Isomer Content in Toluene Diisocyanate
• ASTM D4661: Test Methods for Determination of Total Chlorine in Isocyanates
• ASTM D4663: Test Method for Determination of Hydrolyzable Chlorine in Isocyanates
• ASTM D4877: Test Method for Determination of APHA Color in Isocyanates
• ASTM D5155: Test Methods for Determination of the Isocyanate Content of Aromatic Isocyanates
• ASTM D5629: Test Method for Determination of Acidity in Low-Acidity Aromatic Isocyanates and Polyurethane Prepolymers

ASTM D1786-21 has no known ISO equivalent, highlighting its unique relevance for organizations and manufacturers operating in regions where ASTM standards are adopted.

Summary

ASTM D1786-21 plays a critical role in assuring the quality, safety, and suitability of toluene diisocyanate for the polyurethane industry. By adhering to its requirements, manufacturers and suppliers maintain consistency, enable regulatory compliance, and produce high-quality end products for diverse industrial and consumer markets. For updated practices and regulations, always refer to the latest version as published by ASTM International.

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:D1786 −21
Standard Specification for
Toluene Diisocyanate
This standard is issued under the fixed designation D1786; 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* D5629 Test Method for Polyurethane Raw Materials: Deter-
mination ofAcidity in Low-AcidityAromatic Isocyanates
1.1 This specification covers toluene diisocyanate used as
and Polyurethane Prepolymers
an ingredient in the production of polyurethane materials.
2.2 Federal Standard:
NOTE1—Thepropertiesincludedinthisspecificationarethoserequired
49 CFR Transportation Part 172.01
to characterize toluene diisocyanate. Other requirements are possible and
will be added as the necessary test methods become available.
3. Terminology
1.2 This standard does not purport to address all of the
3.1 Definitions—For definitions of terms used in this
safety concerns, if any, associated with its use. It is the
specification, see Terminology D883.
responsibility of the user of this standard to establish appro-
4. Classification
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4.1 This specification covers three classes of toluene
diisocyanates, based on isomer ratio as described in Table 1.
NOTE 2—There is no known ISO equivalent to this standard.
4.2 Each class is subdivided into three types on the basis of
1.3 This international standard was developed in accor-
acidity and hydrolyzable chloride differences as follows:
dance with internationally recognized principles on standard-
4.2.1 TypeIor A—Acidity shall be less than 0.005 ex-
ization established in the Decision on Principles for the
pressed as percent HCl. Hydrolyzable chloride shall be less
Development of International Standards, Guides and Recom-
than 0.01 %.
mendations issued by the World Trade Organization Technical
4.2.2 Type II or B—Acidity shall be between 0.0070 and
Barriers to Trade (TBT) Committee.
0.012expressedaspercentHCl.Hydrolyzablechlorideshallbe
2. Referenced Documents
less than 0.015 %.
2 4.2.3 Type III or C—Acidity shall be greater than 0.012
2.1 ASTM Standards:
expressed as percent HCl. Hydrolyzable chloride limits are set
D883 Terminology Relating to Plastics
at the convenience of the supplier and purchaser.
D4660 Test Methods for Polyurethane Raw Materials: De-
4.2.4 Toluene diisocyanate that has an acidity value that
termination of the Isomer Content of Toluenediisocyanate
falls between Type I (Type A) and Type II (Type B)isnot
D4661 Test Methods for Polyurethane Raw Materials: De-
currently included in this specification.
termination of Total Chlorine in Isocyanates
D4663 Test Method for Polyurethane Raw Materials: Deter-
5. Requirements
mination of Hydrolyzable Chlorine of Isocyanates
5.1 These materials shall conform to the requirements
D4877 Test Method for Polyurethane Raw Materials: Deter-
prescribed in Table 1.
mination of APHA Color in Isocyanates
D5155 Test Methods for Polyurethane Raw Materials: De-
6. Sampling and Test Methods
termination of the Isocyanate Content ofAromatic Isocya-
6.1 The materials shall be sampled and tested in accordance
nates
withTest Methods D4660, D4661, D4663, D4877, D5155, and
D5629.
This specification is under the jurisdiction of ASTM Committee D20 on
7. Retest and Rejection
Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular
7.1 If any failure occurs, it is acceptable to retest the
Materials - Plastics and Elastomers.
Current edition approved July 1, 2021. Published July 2021. Originally approved
mat
...

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: D1786 − 16 D1786 − 21
Standard Specification for
Toluene Diisocyanate
This standard is issued under the fixed designation D1786; 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 specification covers toluene diisocyanate used as an ingredient in the production of polyurethane materials.
NOTE 1—The properties included in this specification are those required to characterize toluene diisocyanate. Other requirements are possible and will
be added as the necessary test methods become available.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
NOTE 2—There is no known ISO equivalent to this standard.
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 Documents
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D4660 Test Methods for Polyurethane Raw Materials: Determination of the Isomer Content of Toluenediisocyanate
D4661 Test Methods for Polyurethane Raw Materials: Determination of Total Chlorine in Isocyanates
D4663 Test Method for Polyurethane Raw Materials: Determination of Hydrolyzable Chlorine of Isocyanates
D4877 Test Method for Polyurethane Raw Materials: Determination of APHA Color in Isocyanates
D5155 Test Methods for Polyurethane Raw Materials: Determination of the Isocyanate Content of Aromatic Isocyanates
D5629 Test Method for Polyurethane Raw Materials: Determination of Acidity in Low-Acidity Aromatic Isocyanates and
Polyurethane Prepolymers
2.2 Federal Standard:
49 CFR Transportation Part 172.01
3. Terminology
3.1 Definitions—For definitions of terms used in this specification, see Terminology D883.
This specification 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, 2016July 1, 2021. Published April 2016July 2021. Originally approved in 1960. Last previous edition approved in 20102016 as
D1786 - 10.D1786 - 16. DOI: 10.1520/D1786-16.10.1520/D1786-21.
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.
Code of Federal Regulation is available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington,
DC 20401.
*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
D1786 − 21
4. Classification
4.1 This specification covers three classes of toluene diisocyanates, based on isomer ratio as described in Table 1.
4.2 Each class is subdivided into three types on the basis of acidity and hydrolyzable chloride differences as follows:
4.2.1 Type I or A—Acidity shall be less than 0.005 expressed as percent HCl. Hydrolyzable chloride shall be less than 0.01 %.
4.2.2 Type II or B—Acidity shall be betw
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