ASTM D6437-99

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

SCOPE
1.1 This test method covers measuring alkalinity in low-alkalinity (less than 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 similar or equivalent ISO standard.

General Information

• Status: Historical
• Publication Date: 09-Jul-1999
• 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

• Replaced By: ASTM D6437-05 - Standard Test Method for Polyurethane Raw Materials: alkalinity in Low-Alkalinity Polyols (Determination of CPR values of Polyols)
• Effective Date: 01-Mar-2005

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D6437–99
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 D 6437; 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 5. Significance and Use
5.1 This test method is suitable for quality control, as a
1.1 This test method covers measuring alkalinity in low-
alkalinity (<0.002 meq/g basicity) polyols. This alkalinity is specification test and for research. The urethane reaction
often expressed as CPR (controlled polymerization rate) of between polyols and isocyanates to form polyurethane poly-
polyether polyols. This test method is not applicable to mers is known to be sensitive to the presence of basic
amine-based polyols. substances. This is particularly important in the preparation of
1.2 The values stated in SI units are to be regarded as the polyurethane prepolymers which contain isocyanate groups
standard. that are known to react in the presence of trace amounts of
1.3 This standard does not purport to address all of the basic substances. Since many polyether polyols are often made
safety concerns, if any, associated with its use. It is the with strongly basic catalysts, it is important to have an
responsibility of the user of this standard to establish appro- analytical method capable of detecting small quantities of
priate safety and health practices and determine the applica- residual basic substances. This test method is capable of
bility of regulatory limitations prior to use. detecting ppm levels of base (as KOH).
NOTE 1—There is no similar or equivalent ISO standard.
6. Apparatus
6.1 Potentiometric Automatic Titrator, capable of detecting
2. Referenced Documents
multiple titration end points.
2.1 ASTM Standards:
2 6.2 Autotitrator Buret, 5 mL (See Note 2) .
D 883 Terminology Relating to Plastics
6.3 Buret or Dosing Device, capable of dosing 50 mL.
E 180 Practice for Determining the Precision of ASTM
3 6.4 pH Glass Electrode and Reference Electrode or a
Methods forAnalysis and Testing of Industrial Chemicals
Combination Glass Electrode.
E 691 Practice for Conducting an Interlaboratory Study to
6.5 Analytical Balance, capable of weighing to the nearest
Determine the Precision of a Test Method
0.01 g.
3. Terminology
NOTE 2—A1–mLtitratorburetmaybeusedifavailable.Duetothelow
volumes of titrant typically required (0 to 0.5 mL), larger burets will give
3.1 Definitions:
less precise results.
3.1.1 The terminology in this test method is in accordance
with the standard terminology defined in Terminology D 883.
7. Reagents and Materials
3.2 Definitions of Terms Specific to This Standard:
7.1 HCl Aqueous, 0.01 N—Standardize to detect changes of
3.2.1 CPR—controlled polymerization rate is expressed as
0.0001 N.
basicity in milliequivalents per 30 kg of sample (meq/30 kg).
7.2 Methanol, reagent grade
4. Summary of Test Method
8. Procedure
4.1 This test method is a potentiometric titration for sample
8.1 Set up the autotitrator to find multiple end points with a
basicity in methanol solvent. This test method uses a relatively
maximum volume of 5 mL.
largesampleandtitrationwithdiluteacidsolutiontodetermine
8.2 Place 50 6 0.1 mL of methanol solvent in a 100–mL
trace quantities of basicity.
titration cup and titrate a blank using 0.01 N aqueous HCl.
8.3 Weigh 30 6 1.00 g of sample into a titration cup. Add
ThistestmethodisunderthejurisdictionofASTMCommitteeD-20onPlastics
50 6 0.1 mL of reagent grade methanol, stir to mix well, and
and is the direct responsibility of Subcommittee D20.22 on Cellular Materials—
Plastics and Elastomers.
Current edition approved July 10, 1999. Published September 1999.
Annual Book of ASTM Standards, Vol 08.01.
3 5
Annual Book of ASTM Standards, Vol 15.05. H.G. Scholten, J.G. Schuhman, R.E. TenHoor, Journal of Chemical Engineer-
Annual Book of ASTM Standards, Vols 06.03, 08.03, and 14.02. ing Data, 5, 1960, p. 396.
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D6437
TABLE 1 Round-Robin CPR Data in Accordance with Practice
titrate with 0.01 N aqueous HCl. There may be as many as
E180
three end points (breaks) in these titrations. Use the
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