ASTM D5629-11
(Test Method)Standard Test Method for Polyurethane Raw Materials Determination of Acidity in Low-Acidity Aromatic Isocyanates and Polyurethane Prepolymers
Standard Test Method for Polyurethane Raw Materials Determination of Acidity in Low-Acidity Aromatic Isocyanates and Polyurethane Prepolymers
SIGNIFICANCE AND USE
This test method can be used for research or for quality control to characterize aromatic isocyanates and low-acidity prepolymers. Acidity correlates with performance in some polyurethane systems.
SCOPE
1.1 This test method measures the acidity, expressed as ppm of hydrochloric acid (HCl), in aromatic isocyanate or polyurethane prepolymer samples of below 100 ppm acidity. The test method is applicable to products derived from toluene diisocyanate and methylene di(phenylisocyanate) (see Note 1). Refer to Test Method D6099 for determination of acidity in moderate- to high-acidity aromatic isocyanates.
1.2 The values stated in SI units are to be regarded as the 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.
Note 1—This standard is equivalent to ISO 14898, Method B.
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Designation: D5629 − 11
StandardTest Method for
Polyurethane Raw Materials: Determination of Acidity in
Low-Acidity Aromatic Isocyanates and Polyurethane
1
Prepolymers
This standard is issued under the fixed designation D5629; 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 (´) indicates an editorial change since the last revision or reapproval.
4
1. Scope* 2.2 ISO Standards:
ISO 14898Plastics—Aromatic Isocyanates for Use in the
1.1 Thistestmethodmeasurestheacidity,expressedasppm
Production of Polyurethane—Determination of Acidity
of hydrochloric acid (HCl), in aromatic isocyanate or polyure-
thane prepolymer samples of below 100 ppm acidity. The test
3. Terminology
method is applicable to products derived from toluene diiso-
3.1 Definitions—The terminology in this test method fol-
cyanate and methylene di(phenylisocyanate) (see Note 1).
lows the standard terminology defined in Terminology D883.
Refer to Test Method D6099 for determination of acidity in
moderate- to high-acidity aromatic isocyanates.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 acidity, n—the acid strength of a sample expressed in
1.2 The values stated in SI units are to be regarded as the
ppm HCl.
standard.
1.3 This standard does not purport to address all of the
4. Summary of Test Method
safety concerns, if any, associated with its use. It is the
4.1 Theisocyanateismixedwithanexcessofn-propanol,a
responsibility of the user of this standard to establish appro-
cosolvent and a known amount of HCl. Additional acid is
priate safety and health practices and determine the applica-
released into the solvent system during urethane formation.
bility of regulatory limitations prior to use.
The acid is then titrated potentiometrically with methanolic
NOTE 1—This standard is equivalent to ISO 14898, Method B.
KOH. The same procedure is performed with a blank solution
andthedifferenceintiterisusedtocalculatetheaciditypresent
2. Referenced Documents
in the isocyanate sample.
2
2.1 ASTM Standards:
5. Significance and Use
D883Terminology Relating to Plastics
D6099Test Method for Polyurethane Raw Materials: Deter-
5.1 This test method can be used for research or for quality
minationofAcidityinModeratetoHighAcidityAromatic
control to characterize aromatic isocyanates and low-acidity
Isocyanates
prepolymers. Acidity correlates with performance in some
E180Practice for Determining the Precision of ASTM
polyurethane systems.
Methods for Analysis and Testing of Industrial and Spe-
3
cialty Chemicals (Withdrawn 2009) 6. Apparatus
E691Practice for Conducting an Interlaboratory Study to
6.1 Disposable Beakers, 250 mL.
Determine the Precision of a Test Method
6.2 Repipet, pipet or buret, 50 mL.
6.3 Pipet, 100 mL, class A volumetric; or a 100-mL buret
1 with a dosing unit; or a 100-mL repipet, class A volumetric.
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials -
6.4 Potentiometric Titrator:
Plastics and Elastomers.
6.4.1 Reference Electrode—bridge-type electrolyte (double
Current edition approved Feb. 1, 2011. Published March 2011. Originally
approved in 1994. Last previous edition approved in 2005 as D5629-05. DOI: junction), sleeve-type diaphragm, having saturated LiCl/
10.1520/D5629-11.
ethanol solution in both chambers, or equivalent.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
6.4.2 pH Glass Electrode (see Note 2).
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
The last approved version of this historical standard is referenced on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
www.astm.org. 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
---------------------- Page: 1 ----------------------
D5629 − 11
NOTE 2—A combination pH electrode with internal reference is NOTE 4—If a sample is difficult to get into solution, it is acceptable to
acceptable. gently heat and stir to ensure homogeneity.
6.5 Magnetic Stirrer. 11.4 Pipet 100 mL of acidified n-propanol into the solution
so that the volume can be reproduced to 0.05 mL.
6.6 Polytetrafluoroethylene-Coated Stir Bars.
11.5 Add a stir bar, cover with a watch glass and stir for 20
6.7 Watch Glasses.
min. Allow the sample to cool to room temperature after
6.8 Analytical Balance, capable of weighing to the nearest
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:D5629–05 Designation:D5629–11
Standard Test Method for
Polyurethane Raw Materials: Determination of Acidity in
Low-Acidity Aromatic Isocyanates and Polyurethane
1
Prepolymers
This standard is issued under the fixed designation D5629; 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*
1.1This1.1 This test method measures the acidity, expressed as ppm of hydrochloric acid (HCl), in aromatic isocyanate or
polyurethane prepolymer samples of below 100 ppm acidity. The test method is applicable to products derived from toluene
diisocyanate and methylene-bis-(4-phenylisocyanate)methylene di(phenylisocyanate) (see Note 1). Refer to Test Method D6099
for determination of acidity in moderate- to high-acidity aromatic isocyanates.
NOTE1—ISO 14898, Method B is technically equivalent to this test method. for determination of acidity in moderate- to high-acidity aromatic
isocyanates.
1.2 The values stated in SI units are to be regarded as the 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.
NOTE 1—This standard is equivalent to ISO 14898, Method B.
2. Referenced Documents
2
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D6099 Test Method for Polyurethane Raw Materials: Determination of Acidity in Moderate to High Acidity Aromatic
Isocyanates
E180 Practice for Determining the Precision ofASTM Methods forAnalysis and Testing of Industrial and Specialty Chemicals
2.2 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
2.2 ISO Standards:
ISO 14898 Plastics—Aromatic Isocyanates for Use in the Production of Polyurethane—Determination of Acidity
3. Terminology
3.1 Definitions—The terminology in this test method follows the standard terminology defined in Terminology D883.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 acidity, n—the acid strength of a sample expressed in ppm HCl.
4. Summary of Test Method
4.1 The isocyanate is mixed with an excess of n-propanol, a cosolvent and a known amount of HCl.Additional acid is released
into the solvent system during urethane formation. The acid is then titrated potentiometrically with methanolic KOH. The same
procedure is performed with a blank solution and the difference in titer is used to calculate the acidity present in the isocyanate
sample.
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.
Current edition approved March 1, 2005. Published March 2005. Originally approved in 1994. Last previous edition approved in 1999 as D5629-99. DOI:
10.1520/D5629-05.on Cellular Materials - Plastics and Elastomers.
Current edition approved Feb. 1, 2011. Published March 2011. Originally approved in 1994. Last previous edition approved in 2005 as D5629 - 05. DOI:
10.1520/D5629-11.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
---------------------- Page: 1 ----------------------
D5629–11
5. Significance and Use
5.1 This test method can be used for research or for quality control to characterize aromatic isocyanates and low-acidity
prepolymers. Acidity correlates with performance in some polyurethane systems.
6. Apparatus
6.1 Disposable Beakers, 250 mL.
6.2 Repipet,50mL.
6.3, pipet or buret, 50 mL.
6.3 Pipet, 100 mL, classAvolumetric; or a 100-mL buret with a dosimat;dosing unit; or a 100-mL repipet, classAvolumetric.
6.4 Automatic Titration Equipment, such as the f
...
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