RO
SR EN ISO 787-4:2018
General methods of test for pigments and extenders - Part 4: Determination of acidity or alkalinity of the aqueous extract (ISO 787-4:1981)
The principle of the method consists in the hot extraction of the material by following the procedure specified in ISO 787/3, to the stage of obtaining a perfectly clear filtrate. The determination is carried out with indicator solution (method A). If the solution with the methyl red indicator is yellow (alkaline), titrate it with the hydrochloric acid solution to an orange end-point; if the solution with the methyl red indicator is red (acid), titrate it with the sodium or potassium hydroxide solution to an orange end-point. The other method (method B) is the potentiometric determination. Take 100 ml of the test solution, insert the electrodes of the pH measuring device and read the pH value.
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Status :
Valid
Approval date : 4/30/2018
Number of pages : 10
ICS : 87.060.10 Pigments and extenders
Technical Committee : 338 - Adhesives
- Replaces SR ISO 787-4:1994
- Normative reference SR ISO 787-3:1994
- Normative reference SR EN ISO 787-8:2001