BS EN ISO 4629-2:2016 pdf free
BS EN ISO 4629-2:2016 pdf free.Binders for paints and varnishes一Determination of hydroxyl value
This part of ISO 4629 specifies a titrimetric method for determining the hydroxyl value of resins,binders for paints and varnishes, primary alcohols, glycols and fats. Whether it can be applied for hydro carboxylic acids, phenolic hydroxyl groups, polyols such as trimethyl propane and substances containing aromatic groups have been activated for Friedel-Crafts acylation shall be decided on case-to-case basis.
Under the right conditions, the method is also applicable for determining the hydroxyl value of castor oil and its derivatives.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 660, Animal and vegetable fats and oils一Determination of acid value and acidity
ISO 2114:2000, Plastics (polyester resins) and paints and varnishes (binders) 一Determination of partial acid value and total acid value
ISO 3696, Water for analytical laboratory use一Specification and test methods
ISO 4618, Paints and varnishes一Terms and definitions
ISO 15528, Paints, varnishes and raw materials for paints and varnishes一Sampling
Add 30 ml of catalyst solution (5.6) and 10 ml of acetylating reagent (5.5). Close the flask with the stopper and dissolve the sample by stirring and, if necessary, by heating the mixture. Then, while stirring continuously on the magnetic stirrer (6.6), allow the reaction to take place for at least 15 min at
ambient temperature (23±2) °C.
All products containing secondary OH- groups require a reaction time of at least 60 min, and that is also found to be the case for polyols containing secondary 0H-groups.Stop the reaction by adding 3 ml of demineralized water (5.4) and stir for a further 12 min.All products containing secondary 0H-groups require a hydrolysis time of at least 30 min.Remove the flask from the stirrer, rinse the stopper and wall with methyl ethyl ketone (5.3), add two to three drops of indicator solution (5.7) and titrate with potassium hydroxide solution (5.2) until the colourless solution becomes blue (thymolphthalein) or pink (phenolphthalein).BS EN ISO 4629-2 pdf download.
