ASTM D6437-05(2010)e1

Standard Test Method for Polyurethane Raw Materials: alkalinity in Low-Alkalinity Polyols (Determination of CPR values of Polyols)

SIGNIFICANCE AND USE
This test method is suitable for quality control, as a specification test and for research. The urethane reaction between polyols and isocyanates to form polyurethane polymers is known to be sensitive to the presence of basic substances. This is particularly important in the preparation of polyurethane prepolymers which contain isocyanate groups that are known to react in the presence of trace amounts of basic substances. Since many polyether polyols are often made with strongly basic catalysts, it is important to have an analytical method capable of detecting small quantities of residual basic substances. This test method is capable of detecting ppm levels of base (as KOH).
SCOPE
1.1 This test method covers measuring alkalinity in low-alkalinity (0.002 meq/g basicity) polyols. This alkalinity is often expressed as CPR (controlled polymerization rate) of polyether polyols. This test method is not applicable to amine-based polyols.
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—There is no known ISO equivalent to this standard.

General Information

• Status: Historical
• Publication Date: 31-Oct-2010
• ICS: 83.040.01 - Raw materials for rubber and plastics in general
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D6437-05 - Standard Test Method for Polyurethane Raw Materials: alkalinity in Low-Alkalinity Polyols (Determination of CPR values of Polyols)
• Effective Date: 01-Nov-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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
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Designation: D6437 − 05(Reapproved 2010)
Standard Test Method for
Polyurethane Raw Materials: Alkalinity in Low-Alkalinity
Polyols (Determination of CPR Values of Polyols)
This standard is issued under the fixed designation D6437; 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.
´ NOTE—Reapproved with editorial changes in November 2010.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
3.2.1 CPR—controlled polymerization rate is expressed as
1.1 This test method covers measuring alkalinity in low-
basicity in milliequivalents per 30 kg of sample (meq/30 kg).
alkalinity (<0.002 meq/g basicity) polyols. This alkalinity is
often expressed as CPR (controlled polymerization rate) of
4. Summary of Test Method
polyether polyols. This test method is not applicable to
4.1 This test method is a potentiometric titration for sample
amine-based polyols.
basicity in methanol solvent. This test method uses a relatively
1.2 The values stated in SI units are to be regarded as the
largesampleandtitrationwithdiluteacidsolutiontodetermine
standard.
trace quantities of basicity.
1.3 This standard does not purport to address all of the
5. Significance and Use
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5.1 This test method is suitable for quality control, as a
priate safety and health practices and determine the applica-
specification test and for research. The urethane reaction
bility of regulatory limitations prior to use.
between polyols and isocyanates to form polyurethane poly-
mers is known to be sensitive to the presence of basic
NOTE 1—There is no known ISO equivalent to this standard.
substances. This is particularly important in the preparation of
2. Referenced Documents
polyurethane prepolymers which contain isocyanate groups
that are known to react in the presence of trace amounts of
2.1 ASTM Standards:
basic substances. Since many polyether polyols are often made
D883 Terminology Relating to Plastics
with strongly basic catalysts, it is important to have an
E180 Practice for Determining the Precision of ASTM
analytical method capable of detecting small quantities of
Methods for Analysis and Testing of Industrial and Spe-
residual basic substances. This test method is capable of
cialty Chemicals (Withdrawn 2009)
detecting ppm levels of base (as KOH).
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
6. Apparatus
3. Terminology 6.1 Potentiometric Automatic Titrator, capable of detecting
multiple titration end points.
3.1 Definitions:
3.1.1 The terminology in this test method is in accordance 6.2 Autotitrator Buret, 5 mL (See Note 2).
with the standard terminology defined in Terminology D883.
6.3 Buret or Dosing Device, capable of dosing 50 mL.
6.4 pH Glass Electrode and Reference Electrode or a
1 Combination Glass Electrode.
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials -
6.5 Analytical Balance, capable of weighing to the nearest
Plastics and Elastomers.
0.01 g.
Current edition approved Nov. 1, 2010. Published March 2011. Originally
approved in 1999. Last previous edition approved in 2005 as D6437 - 05. DOI:
NOTE 2—A1-mL titrator buret can be used if available. Due to the low
10.1520/D6437-05R10E01.
volumes of titrant typically required (0 to 0.5 mL), larger burets will give
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
less precise results.
contact ASTM 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.
3 4
The last approved version of this historical standard is referenced on H.G. Scholten, J.G. Schuhman, R.E. TenHoor, Journal of Chemical Engineer-
www.astm.org. ing Data, 5, 1960, p. 396.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6437 − 05 (2010)
TABLE 1 Round-Robin CPR Data in Accordance with Practice
7. Reagents and Materials
E180
7.1 HCl Aqueous, 0.01 N—Standardize to detect changes of
Values in CPR Units
0.0001 N. A B C D E
Average S S r R n
r R
Terathane 1000 0.34 0.07 0.20 0.20 0.56 7
7.2 Methanol, reagent grade
Voranol 4702 0.45 0.06 0.11 0.18 0.32 6
Voranol 2120 0.63 0.04 0.12 0.12 0.33 5
8. Procedure
ARCOL E-656 0.60 0.06 0.16 0.16 0.46 7
Multranol 7057 1.24 0.11 0.36 0.30 1.0 6
8.1 Set up the autotitrator to find multiple end points with a
Pooled data . . . 0.07 0.21 0.20 0.59 .
...