ASTM D6437-05

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).3
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.
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 similar or equivalent ISO standard.

General Information

• Status: Historical
• Publication Date: 28-Feb-2005
• 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 D6437-99 - Standard Test Method for Polyurethane Raw Materials: alkalinity in Low-Alkalinity Polyols (Determination of CPR values of Polyols)
• Effective Date: 01-Mar-2005
• Replaced By: ASTM D6437-05(2010)e1 - 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation:D6437–05
Standard Test Method for
Polyurethane Raw Materials: Alkalinity in Low-Alkalinity
1
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.
1. Scope* 4. Summary of Test Method
1.1 This test method covers measuring alkalinity in low- 4.1 This test method is a potentiometric titration for sample
alkalinity (<0.002 meq/g basicity) polyols. This alkalinity is basicity in methanol solvent. This test method uses a relatively
often expressed as CPR (controlled polymerization rate) of largesampleandtitrationwithdiluteacidsolutiontodetermine
polyether polyols. This test method is not applicable to trace quantities of basicity.
amine-based polyols.
5. Significance and Use
1.2 The values stated in SI units are to be regarded as the
standard. 5.1 This test method is suitable for quality control, as a
specification test and for research. The urethane reaction
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the between polyols and isocyanates to form polyurethane poly-
mers is known to be sensitive to the presence of basic
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- substances. This is particularly important in the preparation of
polyurethane prepolymers which contain isocyanate groups
bility of regulatory limitations prior to use.
that are known to react in the presence of trace amounts of
NOTE 1—There is no similar or equivalent ISO standard.
basic substances. Since many polyether polyols are often made
with strongly basic catalysts, it is important to have an
2. Referenced Documents
analytical method capable of detecting small quantities of
2
2.1 ASTM Standards:
residual basic substances. This test method is capable of
D883 Terminology Relating to Plastics
3
detecting ppm levels of base (as KOH).
E180 Practice for Determining the Precision of ASTM
Methods for Analysis and Testing of Industrial and Spe-
6. Apparatus
cialty Chemicals
6.1 Potentiometric Automatic Titrator, capable of detecting
E691 Practice for Conducting an Interlaboratory Study to
multiple titration end points.
Determine the Precision of a Test Method
6.2 Autotitrator Buret, 5 mL (See Note 2) .
6.3 Buret or Dosing Device, capable of dosing 50 mL.
3. Terminology
6.4 pH Glass Electrode and Reference Electrode or a
3.1 Definitions:
Combination Glass Electrode.
3.1.1 The terminology in this test method is in accordance
6.5 Analytical Balance, capable of weighing to the nearest
with the standard terminology defined in Terminology D883.
0.01 g.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 CPR—controlled polymerization rate is expressed as
NOTE 2—A1-mLtitrator buret can be used if available. Due to the low
volumes of titrant typically required (0 to 0.5 mL), larger burets will give
basicity in milliequivalents per 30 kg of sample (meq/30 kg).
less precise results.
1
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
7. Reagents and Materials
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials -
7.1 HCl Aqueous, 0.01 N—Standardize to detect changes of
Plastics and Elastomers.
Current edition approved March 1, 2005. Published March 2005. Originally
0.0001 N.
approved in 1999. Last previous edition approved in 1999 as D6437 - 99. DOI:
7.2 Methanol, reagent grade
10.1520/D6437-05.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on H.G. Scholten, J.G. Schuhman, R.E. TenHoor, Journal of Chemical Engineer-
the ASTM website. ing Data, 5, 1960, p. 396.
*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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D6437–05
TABLE 1 Round-Robin CPR Data in Accordance with Practice
8. Procedure
E180
8.1 Set up the autotitrator to find multiple end points with a
Values in CPR Units
maximum volume of 5 mL.
A B C D E
Average S S r R n
r R
8.2 Place 50 6 0.1 mL of methanol solvent in a 100-mL
Terathane 1000 0.34 0.07 0.20 0.20 0.56 7
titration cup and titrate a blank using 0.01 N aqueous HCl.
Voranol 4702 0.45 0.06 0.11 0.18 0.32 6
8.3 Weigh 30 6 1.00 g of sample into a titration cup. Add
Voran
...