ASTM D6342-12

Standard Practice for Polyurethane Raw Materials: Determining Hydroxyl Number of Polyols by Near Infrared (NIR) Spectroscopy

SIGNIFICANCE AND USE
5.1 General Utility:  
5.1.1 It is necessary to know the hydroxyl number of polyols in order to formulate polyurethane systems.  
5.1.2 This practice is suitable for research, quality control, specification testing, and process control.  
5.2 Limitations:  
5.2.1 Factors affecting the NIR spectra of the analyte polyols need to be determined before a calibration procedure is started. Chemical structure, interferences, any nonlinearities, the effect of temperature, and the interaction of the analyte with other sample components such as catalyst, water and other polyols needs to be understood in order to properly select samples that will model those effects which cannot be adequately controlled.  
5.2.2 Calibrations are generally considered valid only for the specific NIR instrument used to generate the calibration. Using different instruments (even when made by the same manufacturer) for calibration and analysis can seriously affect the accuracy and precision of the measured hydroxyl number. Procedures used for transferring calibrations between instruments are problematic and are to be utilized with caution following the guidelines in Section 16. These procedures generally require a completely new validation and statistical analysis of errors on the new instrument.  
5.2.3 The analytical results are statistically valid only for the range of hydroxyl numbers used in the calibration. Extrapolation to lower or higher hydroxyl values can increase the errors and degrade precision. Likewise, the analytical results are only valid for the same chemical composition as used for the calibration set. A significant change in composition or contaminants can also affect the results. Outlier detection, as discussed in Practices E1655, is a tool that can be used to detect the possibility of problems such as those mentioned above.
SCOPE
1.1 This standard covers a practice for the determination of hydroxyl numbers of polyols using NIR spectroscopy.  
1.2 Definitions, terms, and calibration techniques are described. Procedures for selecting samples, and collecting and treating data for developing NIR calibrations are outlined. Criteria for building, evaluating, and validating the NIR calibration model are also described. Finally, the procedure for sample handling, data gathering and evaluation are described.  
1.3 The implementation of this standard requires that the NIR spectrometer has been installed in compliance with the manufacturer's specifications.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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 ISO 15063.

General Information

• Status: Historical
• Publication Date: 31-Jul-2012
• ICS: 83.080.10 - Thermosetting materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D6342-08 - Standard Practice for Polyurethane Raw Materials: Determining Hydroxyl Number of Polyols by Near Infrared (NIR) Spectroscopy
• Effective Date: 01-Aug-2012

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: D6342 − 12
Standard Practice for
Polyurethane Raw Materials: Determining Hydroxyl Number
1
of Polyols by Near Infrared (NIR) Spectroscopy
This standard is issued under the fixed designation D6342; 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* E131 Terminology Relating to Molecular Spectroscopy
E168 Practices for General Techniques of Infrared Quanti-
1.1 This standard covers a practice for the determination of
tative Analysis
hydroxyl numbers of polyols using NIR spectroscopy.
E222 Test Methods for Hydroxyl Groups Using Acetic
1.2 Definitions, terms, and calibration techniques are de-
Anhydride Acetylation
scribed. Procedures for selecting samples, and collecting and
E275 Practice for Describing and Measuring Performance of
treating data for developing NIR calibrations are outlined.
Ultraviolet and Visible Spectrophotometers
Criteria for building, evaluating, and validating the NIR
E456 Terminology Relating to Quality and Statistics
calibration model are also described. Finally, the procedure for
E1655 Practices for Infrared Multivariate Quantitative
sample handling, data gathering and evaluation are described.
Analysis
1.3 The implementation of this standard requires that the E1899 Test Method for Hydroxyl Groups Using Reaction
with p-ToluenesulfonylIsocyanate(TSI)andPotentiomet-
NIR spectrometer has been installed in compliance with the
manufacturer’s specifications. ric Titration with Tetrabutylammonium Hydroxide
2.2 ISO Standard:
1.4 The values stated in SI units are to be regarded as
ISO 15063 Plastics—Polyols for use in the production of
standard. No other units of measurement are included in this
polyurethanes—Determination of hydroxyl number by
standard.
NIR spectroscopy
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions—Terminology used in this practice follows
priate safety and health practices and determine the applica-
that defined in Terminology D883. For terminology related to
bility of regulatory limitations prior to use.
molecular spectroscopy methods, refer to Terminology E131.
NOTE 1—This standard is equivalent ISO 15063.
For terms relating to multivariate analysis, refer to Practice
E1655.
2. Referenced Documents
2 3.2 Definitions of Terms Specific to This Standard:
2.1 ASTM Standards:
3.2.1 hydroxyl number—the milligrams of potassium hy-
D883 Terminology Relating to Plastics
droxide equivalent to the hydroxyl content of1gof sample.
D4274 Test Methods for Testing Polyurethane Raw Materi-
als: Determination of Hydroxyl Numbers of Polyols
4. Summary of Practice
D4855 Practice for Comparing Test Methods (Withdrawn
3
2008) 4.1 Multivariate mathematics is applied to correlate the NIR
absorbance values for a set of calibration samples to the
respective reference hydroxyl number for each sample. The
1
resultant multivariate calibration model is then applied to the
This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics
analysis of unknown samples to provide an estimate of their
and Elastomers.
hydroxyl numbers.
Current edition approved Aug. 1, 2012. Published September 2012. Originally
approved in 1998. Last previous edition approved in 2008 as D6342 - 08. DOI:
4.2 Multilinear regression (MLR), principal components
10.1520/D6342-12.
regression (PCR), and partial least squares regression (PLS)
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
are the mathematical techniques used for the development of
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 calibration model.
the ASTM website.
3
4.3 Statistical tests are used to detect outliers during the
The last approved version of this historical standard is referenced on
www.astm.org. development of the calibration model. Outliers can include
*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

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D6342 − 12
high leverage samples and samples whose hydroxyl numbers
are inconsistent with the model.
4.4 Validation of the calibration model is performed by
using the model to analyze a set of validation samples. The
hydroxyl number estimates for the vali
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM 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: D6342 − 08 D6342 − 12
Standard Practice for
Polyurethane Raw Materials: Determining Hydroxyl Number
1
of Polyols by Near Infrared (NIR) Spectroscopy
This standard is issued under the fixed designation D6342; 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*
1.1 This standard covers a practice for the determination of hydroxyl numbers of polyols using NIR spectroscopy.
1.2 Definitions, terms, and calibration techniques are described. Procedures for selecting samples, and collecting and treating
data for developing NIR calibrations are outlined. Criteria for building, evaluating, and validating the NIR calibration model are
also described. Finally, the procedure for sample handling, data gathering and evaluation are described.
1.3 The implementation of this standard requires that the NIR spectrometer has been installed in compliance with the
manufacturer’s specifications.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 This standard is no equivalent or similar ISO standard.15063.
2. Referenced Documents
2
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
D4274 Test Methods for Testing Polyurethane Raw Materials: Determination of Hydroxyl Numbers of Polyols
3
D4855 Practice for Comparing Test Methods (Withdrawn 2008)
E131 Terminology Relating to Molecular Spectroscopy
E168 Practices for General Techniques of Infrared Quantitative Analysis
E222 Test Methods for Hydroxyl Groups Using Acetic Anhydride Acetylation
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
E456 Terminology Relating to Quality and Statistics
E1655 Practices for Infrared Multivariate Quantitative Analysis
E1899 Test Method for Hydroxyl Groups Using Reaction with p-Toluenesulfonyl Isocyanate (TSI) and Potentiometric Titration
with Tetrabutylammonium Hydroxide
2.2 ISO Standard:
ISO 15063 Plastics—Polyols for use in the production of polyurethanes—Determination of hydroxyl number by NIR
spectroscopy
3. Terminology
3.1 Definitions—Terminology used in this practice follows that defined in Terminology D883. For terminology related to
molecular spectroscopy methods, refer to Terminology E131. For terms relating to multivariate analysis, refer to Practice E1655.
3.2 Definitions of Terms Specific to This Standard:
1
This practice is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics and
Elastomers.
Current edition approved March 1, 2008Aug. 1, 2012. Published April 2008September 2012. Originally approved in 1998. Last previous edition approved in 20032008
as D6342 - 98D6342 - 08.(2003). DOI: 10.1520/D6342-08.10.1520/D6342-12.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
The last approved version of this historical standard is referenced on www.astm.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 ----------------------
D6342 − 12
3.2.1 hydroxyl number—the milligrams of potassium hydroxide equivalent to the hydroxyl content of 1 g of sample.
4. Summary of Practice
4.1 Multivariate mathematics is applied to correlate the NIR absorbance values for a set of calibration samples to the respective
reference hydroxyl number for each sample. The resultant multivariate calibration model is then applied to the analysis of unknown
samples to provide an estimate of their hydroxyl numbers.
4.2 Multilinear regression (MLR), principal components regression (PCR), and partial least squares regression (PLS) are the
mathematical techniques used for the development of the calibrati
...