ASTM D5523-10

Standard Test Method for Polyurethane Raw Materials Acidity by Argentometric Determination of Hydrolyzable Chlorine in Monomeric, Aromatic Isocyanates

SIGNIFICANCE AND USE
This test method is suitable for research or for quality control to characterize TDI and MDI.
This test method was developed to overcome problems with low-level acidity determinations that use glass electrodes in the presence of reagent alcohol solvents. Reagent alcohols contain acidic and basic species, which complicate the glass electrode methods at low levels of acidity.
SCOPE
1.1 This test method measures the hydrolyzable chlorine content of monomeric, aromatic isocyanates used as polyurethane raw materials and expresses it as HCl acidity. The test method is applicable to toluene diisocyanate (TDI) and monomeric methylene di(phenylisocyanate), known as MDI. The main sources of hydrolyzable chlorine and, therefore, acidity in monomeric aromatic isocyanates are carbamyl chlorides, acid chlorides, and dissolved phosgene. All of these compounds react with alcohols and water to form hydrochloric acid.
1.2 This test method applies only to monomeric isocyanates in which all of the acidity is derived from species that generate HCl on solvolysis.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 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—There is no known ISO equivalent to this standard.

General Information

• Status: Historical
• Publication Date: 31-Jul-2010
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D5523-04 - Standard Test Method for Polyurethane Raw Materials Acidity by Argentometric Determination of Hydrolyzable Chlorine in Monomeric, Aromatic Isocyanates
• Effective Date: 01-Aug-2010

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D5523 − 10
StandardTest Method for
Polyurethane Raw Materials: Acidity by Argentometric
Determination of Hydrolyzable Chlorine in Monomeric,
1
Aromatic Isocyanates
This standard is issued under the fixed designation D5523; 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 3.2.1 acidity—the acid strength of a sample expressed as
parts per million hydrochloric acid (HCl) present.
1.1 This test method measures the hydrolyzable chlorine
3.2.2 hydrolyzable chlorine—the amount of chlorine re-
content of monomeric, aromatic isocyanates used as polyure-
leased as chloride ion under the conditions of the test,
thane raw materials and expresses it as HCl acidity. The test
expressed as parts per million chlorine.
method is applicable to toluene diisocyanate (TDI) and mono-
meric methylene di(phenylisocyanate), known as MDI. The
4. Summary of Test Method
mainsourcesofhydrolyzablechlorineand,therefore,acidityin
monomeric aromatic isocyanates are carbamyl chlorides, acid 4.1 The sample reacts with 2-propanol to form urethanes
and hydrochloric acid, which is liberated from the labile
chlorides, and dissolved phosgene. All of these compounds
react with alcohols and water to form hydrochloric acid. carbamyl chlorides, acid chlorides, and dissolved phosgene.
The chlorides of the liberated acid are then determined
1.2 This test method applies only to monomeric isocyanates
potentiometrically using standard methanolic silver nitrate
in which all of the acidity is derived from species that generate
solution and calculated as parts per million HCl.
HCl on solvolysis.
1.3 The values stated in SI units are to be regarded as the 5. Significance and Use
standard.
5.1 This test method is suitable for research or for quality
1.4 This standard does not purport to address all of the
control to characterize TDI and MDI.
safety concerns, if any, associated with its use. It is the
5.2 This test method was developed to overcome problems
responsibility of the user of this standard to establish appro-
with low-level acidity determinations that use glass electrodes
priate safety and health practices and determine the applica-
in the presence of reagent alcohol solvents. Reagent alcohols
bility of regulatory limitations prior to use.
contain acidic and basic species, which complicate the glass
NOTE 1—There is no known ISO equivalent to this standard. electrode methods at low levels of acidity.
2. Referenced Documents 6. Interferences
2
2.1 ASTM Standards:
6.1 Acidic species that do not generate chloride ions under
D883 Terminology Relating to Plastics the conditions of this test method will not be determined
because acidity is determined indirectly from the chloride ion
3. Terminology
concentration.
3.1 Definitions: For definitions of terms used in this test
6.2 Acidic species that do not produce chloride ions are
method, see Terminology D883.
expected to be negligible at low levels of acidity and for the
3.2 Definitions of Terms Specific to This Standard: monomeric isocyanates in this test method.
6.3 Care must be taken to avoid chloride contamination of
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics glassware and sample containers.
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials -
Plastics and Elastomers.
7. Apparatus
Current edition approved Aug. 1, 2010. Published September 2010. Originally
ϵ1
7.1 Potentiometric Titrator.
approved in 1994. Last previous edition approved in 2004 as D5523 - 04 . DOI:
10.1520/D5523-10.
7.2 Combination Silver Billet Electrode (Note 2).
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
7.3 Oven, 70°C (Note 3).
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 7.4 Magnetic Stirrer.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D5523 − 10
NOTE 2—The combination silver billet electrode is to be stored in 0.01
11. Procedure
N methanolic silver nitrate solution in order to keep the electrode
11.1 Weigh10.0gofthesampleintoabeakerandrecordthe
conditioned properly. The use of chloride containing solutions must be
weight to the nearest 0.0001 g (Note 4).
avoided during storage and maintenance of the apparatus.
NOTE 3—Monomeric MDI samples can be solid when received in the
11.2 Add100mLof2-propanoltothebeaker,cover,andstir
laboratory.An oven is to be used to melt the 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:D5523–04 Designation:D5523–10
Standard Test Method for
Polyurethane Raw Materials: Acidity by Argentometric
Determination of Hydrolyzable Chlorine in Monomeric,
1
Aromatic Isocyanates
This standard is issued under the fixed designation D5523; 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 measures the hydrolyzable chlorine content of monomeric, aromatic isocyanates used as polyurethane raw
materials and expresses it as HCl acidity. The test method is applicable to toluene diisocyanate (TDI) and monomeric
methylene-bis-(4-phenylisocyanate),methylene di(phenylisocyanate), known as MDI. The main sources of hydrolyzable chlorine
and, therefore, acidity in monomeric aromatic isocyanates are carbamyl chlorides, acid chlorides, and dissolved phosgene. All of
these compounds react with alcohols and water to form hydrochloric acid.
1.2 This test method applies only to monomeric isocyanates in which all of the acidity is derived from species that generate HCl
on solvolysis.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 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.
NOTE1—There is no equivalent ISO standard. 1—There is no known ISO equivalent to this standard.
2. Referenced Documents
2
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
3. Terminology
3.1 Definitions: —For For definitions of terms used in this test method, see Terminology D883.
3.1.1Discussion—Polyurethanes or urethanes, as they are sometimes called, can be thermosetting, thermoplastic, rigid or soft
and flexible, or cellular or solid (see Terminology D883).
3.2 Definitions of Terms Specific to This Standard:
3.2.1 acidity—the acid strength of a sample expressed as parts per million hydrochloric acid (HCl) present in the sample.
present.
3.2.2 hydrolyzable chlorine—the amount of chlorine released as chloride ion under the conditions of the test, expressed inas
parts per million of chlorine in the sample. chlorine.
4. Summary of Test Method
4.1 The sample reacts with 2-propanol to form urethanes and hydrochloric acid, which is liberated from the labile carbamyl
chlorides, acid chlorides, and dissolved phosgene. The chlorides of the liberated acid are then determined potentiometrically using
standard methanolic silver nitrate solution and calculated as parts per million HCl.
5. Significance and Use
5.1 This test method can be usedis suitable for research or for quality control to characterize TDI and MDI.
5.2 This test method was developed to overcome problems with low-level acidity determinations that use glass electrodes in the
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 Plastics.
on Cellular
Current edition approved October 1, 2004. Published October 2004. Originally approved in 1994. Last previous edition approved in 1999 as D5523-94(1999)
Materials - Plastics and Elastomers.
´1
Current edition approved Aug. 1, 2010. Published September 2010. Originally approved in 1994. Last previous edition approved in 2004 as D5523 - 04 . DOI:
10.1520/D5523-04. DOI: 10.1520/D5523-10.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM 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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D5523–10
presence of reagent alcohol solvents. Reagent alcohols contain acidic and basic species, which complicate the glass electrode
methods at low levels of acidity.
6. Interferences
6.1Any acidic 6.1 Acidic species that doesdo not generate chloride ions under the conditions of this test method will not be
determined because acidity is determined indirectly from the chloride ion concentration.
6.2 Acidic species that
...