ASTM D5155-01

Standard Test Methods for Polyurethane Raw Materials Determination of the Isocyanate Content of Aromatic Isocyanates

SCOPE
1.1 These test methods measure the isocyanate content of aromatic isocyanates used as polyurethane raw materials.
1.1.1 Test Method A—Unheated toluene-dibutylamine determines the amount of toluene diisocyanate in refined toluene-2,4-diisocyanate and toluene-2,6-diisocyanate, or mixtures of the two. Other isomers, if present, will be included in the determination. This test method may also be applied to other isocyanates of suitable reactivity and solubility.
1.1.2 Test Method B—Heated toluene-dibutylamine determines the amine equivalent of crude or modified isocyanates derived from toluene diisocyanate, methylenebis-(4-phenylisocyanate), and polymethylene polyphenylisocyanate.
1.1.3 Test Method C—Unheated trichlorobenzene-toluene-dibutylamine determines the isocyanate content of crude or modified isocyanates derived from toluene diisocyanate, methylene-bis-(4-phenylisocyanate), and polymethylene polyphenylisocyanate. This test method can also be used to assay isomer mixtures of toluene diisocyanate and methylene- bis-(phenylisocyanate).
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.For specific warning and precautionary statements, see Note 1.
Note 2—Method C of this test method is equivalent to Method B of ISO 14896.

General Information

• Status: Historical
• Publication Date: 09-Nov-2001
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D5155-96 - Standard Test Methods for Polyurethane Raw Materials Determination of the Isocyanate Content of Aromatic Isocyanates
• Effective Date: 10-Nov-2001
• Replaced By: ASTM D5155-07 - Standard Test Methods for Polyurethane Raw Materials Determination of the Isocyanate Content of Aromatic Isocyanates
• Effective Date: 01-Apr-2007
• Referred By: ASTM D1786-21 - Standard Specification for Toluene Diisocyanate
• Effective Date: 10-Nov-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D5155–01
Standard Test Methods for
Polyurethane Raw Materials: Determination of the
1
Isocyanate Content of Aromatic Isocyanates
This standard is issued under the fixed designation D5155; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
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1. Scope* Methods forAnalysis andTesting of Industrial Chemicals
2.2 ISO Standard:
1.1 These test methods measure the isocyanate content of
ISO14896 Polyurethane Raw Materials-Determination of
aromatic isocyanates used as polyurethane raw materials.
Isocyanate Content
1.1.1 Test Method A—Unheated toluene-dibutylamine de-
terminestheamountoftoluenediisocyanateinrefinedtoluene-
3. Terminology
2,4-diisocyanate and toluene-2,6-diisocyanate, or mixtures of
3.1 Definitions:
the two. Other isomers, if present, will be included in the
3.1.1 polyurethane, n—a polymer prepared by the reaction
determination. This test method may also be applied to other
of an organic diisocyanate or polyisocyanate with compounds
isocyanates of suitable reactivity and solubility.
containing hydroxyl groups.
1.1.2 Test Method B—Heated toluene-dibutylamine deter-
3.1.1.1 Discussion—Polyurethanesorurethanes,astheyare
mines the amine equivalent of crude or modified isocyanates
sometimes called, may be thermosetting, thermoplastic, rigid
derived from toluene diisocyanate, methylenebis-(4-
or soft and flexible, or cellular or solid (see Terminology
phenylisocyanate), and polymethylene polyphenylisocyanate.
D883).
1.1.3 Test Method C—Unheated trichlorobenzene-toluene-
3.2 Definitions of Terms Specific to This Standard:
dibutylamine determines the isocyanate content of crude or
3.2.1 amine equivalent—the weight of sample that will
modified isocyanates derived from toluene diisocyanate,
combine with 1.0-g equivalent weight of dibutylamine.
methylene-bis-(4-phenylisocyanate), and polymethylene
3.2.2 assay—the percent by weight of toluene diisocyanate
polyphenylisocyanate. This test method can also be used to
present in the sample.
assay isomer mixtures of toluene diisocyanate and methylene-
3.2.3 isocyanate (NCO) content—the weight percent of the
bis-(phenylisocyanate).
NCO groups present in the sample.
1.2 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Methods
responsibility of the user of this standard to establish appro-
4.1 All three test methods react the isocyanate sample with
priate safety and health practices and determine the applica-
an excess of dibutylamine to form the corresponding urea.The
bility of regulatory limitations prior to use. For specific
NCO content is determined from the amount of dibutylamine
warning and precautionary statements, see Note 2.
consumed in the reaction. Each test method varies solvent or
NOTE 1—Method C of this test method is equivalent to Method B of
heating times to yield accurate assays of the sample in
ISO 14896.
question.
4.1.1 Test Method A—The sample is added to an excess of
2. Referenced Documents
dibutylamineintolueneandallowedtostandatroomtempera-
2.1 ASTM Standards:
ture for 15 min. The reaction mixture is diluted with isopropyl
2
D883 Terminology Relating to Plastics
alcohol, and the excess dibutylamine is back-titrated with
3
D1193 Specification for Reagent Water
hydrochloric acid.
E180 Practice for Determining the Precision of ASTM
4.1.2 Test Method B—The sample is added to an excess of
dibutylamine in toluene and stirred for 20 min. The resulting
solution is then heated rapidly to 100°C, removed from the
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These test methods are under the jurisdiction of ASTM Committee D20 on
heat, and allowed to stand for 30 min. The reaction mixture is
Plastics and are the direct responsibility of Subcommittee D20.22 on Cellular
Materials-PlasticsandElastomers.ThesetestmethodswererecommendedtoASTM diluted with isopropyl alcohol, and the excess dibutylamine is
by the Society of the Plastics Industry Polyurethane Raw Materials Analysis
back-titrated with hydrochloric acid.
Committee.
Current edition approved November 10, 2001. Published January 2002. Origi-
nally published as D5155–91. Last previous edition D5155–96.
2
Annual Book of ASTM Standards, Vol 08.01.
3 4
Annual Book of ASTM Standards, Vol 11.01. Annual Book of ASTM Standards, Vol 15.05.
*A Summary of Changes section appears at the end of this standard.
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D5155–01
4.1.3 Test Method C—The sample is added to a solution of 10.2 Cooling Bath—Any container
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