ASTM D6099-03
(Test Method)Standard Test Method for Polyurethane Raw Materials: Determination of Acidity in Moderate to High Acidity Aromatic Isocyanates
Standard Test Method for Polyurethane Raw Materials: Determination of Acidity in Moderate to High Acidity Aromatic Isocyanates
SIGNIFICANCE AND USE
This test method can be used for research or for quality control to characterize aromatic isocyanates and prepolymers of moderate to high acidity. Acidity correlates with performance in some polyurethane systems.
SCOPE
1.1 this test method determines the acidity, expressed as parts per million (ppm) of HCI, in aromatic isocyanate samples of greater than 100-ppm acidity. The test method is applicable to products derived from toluene diisocyanate and methylene-bis-(4-phenylisocyanate) (see Note 1).
Note 1—This test method is equivalent to ISO 14898, Test Method A.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6099–03
Standard Test Method for
Polyurethane Raw Materials: Determination of Acidity in
1
Moderate to High Acidity Aromatic Isocyanates
This standard is issued under the fixed designation D 6099; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope* metrically with methanolic KOH, and the acidity present in the
isocyanate sample is calculated from the titer.
1.1 This test method determines the acidity, expressed as
parts per million (ppm) of HCl, in aromatic isocyanate samples
5. Significance and Use
of greater than 100–ppm acidity. The test method is applicable
5.1 This test method can be used for research or for quality
to products derived from toluene diisocyanate and methylene-
control to characterize aromatic isocyanates and prepolymers
bis-(4–phenylisocyanate) (see Note 1).
of moderate to high acidity. Acidity correlates with perfor-
NOTE 1—This test method is equivalent to ISO 14898, Test MethodA.
mance in some polyurethane systems.
2. Referenced Documents
6. Apparatus
2.1 ASTM Standards:
6.1 250-mL Beakers.
2
D 883 Terminology Relating to Plastics
6.2 50-mL Pipet or Repipet, Class A volumetric.
E 180 Practice for Determining the Precision of ASTM
6.3 100-mL Pipet or Repipet, Class A volumetric.
Methods for Analysis and Testing of Industrial and Spe-
6.4 Automatic Titration Equipment, such as:
3
cialty Chemicals 6
6.4.1 Titroprocessor , and
6
E 691 Practice for Conducting an Interlaboratory Study to
6.4.2 Dosimat , with magnetic stirrer.
4
Determine the Precision of a Test Method 7
6.4.3 Reference Electrode , with saturated LiCl/ethanol so-
2.2 ISO Standards:
lution in both chambers.
ISO 14898 Plastics—Aromatic isocyanates for use in the 8
6.4.4 pH Glass Electrode , (see Note 2).
5
production of polyurethane—Determination of acidity
NOTE 2—Acombination pH electrode with internal reference also may
be used.
3. Terminology
3.1 Definitions—Terms used in this test method are in 6.5 Magnetic Stirrer.
6.6 Stir Bars.
accordance with Terminology D 883.
3.2 Definitions of Terms Specific to This Standard: 6.7 Watch Glasses.
6.8 Analytical Balance, capable of weighing to the nearest 1
3.2.1 acidity, n—the acid strength of a sample expressed in
ppm hydrochloric acid. mg.
7. Reagents and Materials
4. Summary of Test Method
4.1 The isocyanate is mixed with an excess of methanol and 7.1 0.02 N KOH in Methanol—1.32 g KOH pellets (85 %
KOH)/1000 mLmethanol, standardized with potassium hydro-
a cosolvent.Additional acid is released into the solvent system
during urethane formation. The acid then is titrated potentio- gen phthalate (KHP).
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
6
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials— Instruments similar to and including the Metrohn 686 Titroprocessor with a
Plastics and Elastomers. Metrohn 665 Dosimat/magnetic stirrer as supplied by Brinkman Instruments Co.,
Current edition approved March 10, 2003. Published April 2003. Originally Cantiague Road,Westbury, NY11590-9974, or an equivalent instrument, have been
approved in 1997. Last previous edition approved in 1997 as D 6099 - 97. found to be satisfactory for this analysis.
2 7
Annual Book of ASTM Standards, Vol. 08.01. The Brinkman CAT. #020-94-400-5, or its equivalent: bridge electrolyte
3
Annual Book of ASTM Standards, Vol. 15.05. (double junction), sleeve-type diaphragm, has been found satisfactory for this
4
Annual Book of ASTM Standards, Vol. 14.02. analysis. See Footnote 5 for the address to Brinkman Instruments Co.
5 8
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St., The Brinkman CAT. #020-91-012-7, or its equivalent, has been found satisfac-
4th Floor, New York, NY 10036. tory for this analysis. See Footnote 5 for the address to Brinkman Instruments Co.
*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.
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D6099–03
7.2 Tolueneor1,2,4–Trichlorobenzene(TCB),driedfor24h
where:
over molecular sieves.
Vsam = volume of titrant needed for the sample, mL,
7.3 Anhydrous Methanol.
N = normality of the titrant solution, and
F=36 = 36.465 (mol weight of HCl) 3 1000 (factor
8. Sampling
465 to change mg/g to µg/g, that is, ppm).
8.1 Since organic isocyanates react with atmospheric mois-
13. Report
ture,takespecialprecautionsinsampling.(Warning—Organic
13.1 The result is reported as the average of duplicates,
isocyanates are toxic
...
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