BS EN ISO 14896:2001:2002 Edition
$102.76
Plastics. Polyurethane raw materials. Determination of isocyanate content
| Published By | Publication Date | Number of Pages |
| BSI | 2002 | 20 |
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 5 | Plastics�— Polyurethane raw materials�— Determination of isocyanate content |
| 7 | Contents Page |
| 8 | Foreword |
| 9 | Plastics�— Polyurethane raw materials�— Determination of isocyanate content 1��� Scope 2��� Normative references 3��� Terms and definitions |
| 10 | 4��� Principle 4.1��� Method�A 4.2��� Method�B 5��� Application 6��� Interferences 7��� Sampling |
| 11 | 8��� Test conditions 9��� Reagents 9.1��� Acetone 9.2��� Toluene 9.3��� di- 9.4��� di- 9.5��� Aqueous hydrochloric acid 9.6��� Methanolic hydrochloric acid 9.7��� Bromophenol blue indicator solution 9.8��� 1,2,4-Trichlorobenzene 9.9��� Methanol 10��� Apparatus 10.1��� Potentiometric titrator 10.2��� Syringes 10.3��� Magnetic stirrer 10.4��� Analytical balance |
| 12 | 10.5��� Iodine flask 10.6��� Conical flask 10.7��� Volumetric pipettes 10.8��� Measuring pipette 10.9��� Graduated cylinders 10.10��� Beaker 10.11��� Burette 11��� Method�A — Toluene/dibutylamine with aqueous HCl 11.1��� Procedure 11.1.1��� Using a volumetric pipette ( 11.1.2��� Weigh a sample of the product to be analysed to the nearest 11.1.3��� After complete dissolution, allow to react for 11.1.4��� Using a graduated cylinder ( 11.1.5��� Titrate the excess dibutylamine using one of the two following procedures: 11.1.5.1��� Potentiometric titration (recommended) 11.1.5.2��� Colorimetric titration |
| 13 | 11.1.6��� Conduct a blank determination under identical conditions, except omit the test portion. 11.2��� Expression of results 11.2.1��� Calculate the %�NCO as follows: 11.2.2��� The amine equivalent may be calculated as follows: 11.2.3��� For isocyanates based on a single isomer or isomer mixture (for example, “pure” TDI or … 11.2.4��� The number of equivalents per kilogram (equiv/kg) may be calculated as follows: |
| 14 | 11.2.5��� In refined isocyanates, acidic impurities are usually present in such low amounts that … 11.3��� Precision and bias 11.3.1��� Precision 11.3.2��� Bias 11.4��� Test report 12��� Method�B — Toluene/TCB/DBA with methanolic HCl 12.1��� Procedure 12.1.1��� Introduce |
| 15 | 12.1.2��� Transfer the approximate amount of sample required, weighed to the nearest 12.1.3��� Cover the flask and swirl the contents until the solution is homogeneous. The reaction … 12.1.4��� Let the reaction mixture stand until it reaches room temperature ( 12.1.5��� Titrate potentiometrically with 12.1.6��� Prepare a blank exactly as described above, but without adding the test portion. Titrat… 12.1.7��� If a potentiometric titrator is not available, the titration can be performed using a c… 12.2��� Expression of results 12.2.1��� As required, calculate the %�NCO, amine equivalent, or equivalents per kilogram followi… 12.2.2��� In refined isocyanates, acidic impurities are usually present in such low amounts that … |
| 16 | 12.2.3��� The amine equivalent, corrected for acidity, may be calculated as follows: 12.3��� Precision and bias 12.3.1��� Use the following criteria to judge the acceptability of results for crude or modified … 12.3.1.1��� Repeatability (single analyst) 12.3.1.2��� Reproducibility (multilaboratory) 12.3.2��� Use the following criteria to judge the acceptability of results for MDI isomers: 12.3.2.1��� Repeatability 12.3.2.2��� Reproducibility 12.3.3��� TDI isomers were evaluated. However, there were insufficient degrees of freedom to make… 12.3.4��� Bias is the difference between the expectation of the test results and an accepted refe… 12.4��� Test report |
