ASTM D2572-97(2010)
(Test Method)Standard Test Method for Isocyanate Groups in Urethane Materials or Prepolymers (Withdrawn 2019)
Standard Test Method for Isocyanate Groups in Urethane Materials or Prepolymers (Withdrawn 2019)
SIGNIFICANCE AND USE
The percent NCO is used to establish unit ratios for stoichiometric reactions with co-reactants.
SCOPE
1.1 This test method covers the determination of the isocyanate group (NCO) content of a urethane intermediate or prepolymer.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.
WITHDRAWN RATIONALE
This test method covers the determination of the isocyanate group (NCO) content of a urethane intermediate or prepolymer.
Formerly under the jurisdiction of Committee D01 on Paint and Related Coatings, Materials, and Applications, this test method was withdrawn in July 2019 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D2572 − 97 (Reapproved 2010)
Standard Test Method for
Isocyanate Groups in Urethane Materials or Prepolymers
This standard is issued under the fixed designation D2572; 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.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 5. Interferences
5.1 Phosgene, the carbamyl chloride of isocyanate, hydro-
1.1 This test method covers the determination of the isocya-
gen chloride, or any other acidic or basic impurities of
nate group (NCO) content of a urethane intermediate or
sufficient strength will interfere. The concentration of these
prepolymer.
compounds is usually sufficiently low that their effect on the
1.2 The values stated in SI units are to be regarded as
determination is negligible.
standard. No other units of measurement are included in this
standard.
6. Apparatus
1.3 This standard does not purport to address all of the
6.1 Polyethylene Stoppers (or corks) covered with alumi-
safety concerns, if any, associated with its use. It is the
num foil to fit 250-mL Erlenmeyer flasks.
responsibility of the user of this standard to establish appro-
6.2 Magnetic Stirrer with PTFE-fluorocarbon-covered stir-
priate safety and health practices and determine the applica-
ring bar.
bility of regulatory limitations prior to use. For specific hazard
statements, see Section 8.
6.3 Pipet, 25-mL.
6.4 Buret, 50- or 100-mL.
2. Referenced Documents
6.5 Analytical Balance.
2.1 ASTM Standards:
D841 Specification for Nitration Grade Toluene
7. Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be
3. Summary of Test Method
used in all tests unless otherwise specified. Unless otherwise
3.1 The urethane prepolymer is allowed to react with an indicated, it is intended that all reagents shall conform to the
excess of di-n-butylamine in toluene (Note 1). After the specifications of the Committee on Analytical Reagents of the
reaction is complete, the excess of di-n-butylamine is deter- American Chemical Society, where such specifications are
mined by back titration with standard hydrochloric acid. available. Other grades may be used, provided that it is first
ascertained that the reagent is of sufficiently high purity to
NOTE 1—Solvents other than toluene may be needed in some cases, for
permit its use without lessening the accuracy of the determi-
example, anhydrous dimethylformamide (DMF), but the procedure has
nation.
not been evaluated using them.
7.2 Bromphenol Blue Indicator, Prepare 0.1 % solution by
4. Significance and Use
mixing 0.10 g of acid, nonwater soluble bromphenol blue with
1.5 mLof 0.1 N sodium hydroxide solution and diluting to 100
4.1 The percent NCO is used to establish unit ratios for
mL with distilled water.
stoichiometric reactions with co-reactants.
7.3 Di-n-butylamine Solution, 0.1 N in dry toluene. Not
standardized.
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.33 on Polymers and Resins. Burets and pipets shall conform to National Institute of Standards and
Current edition approved Dec. 1, 2010. Published December 2010. Originally Technology tolerances.
ε1
approved in 1967. Last previous edition approved in 2003 as D2572 – 97 (2003) . Reagent Chemicals, American Chemical Society Specifications, American
DOI: 10.1520/D2572-97R10. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC)
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.