ISO 4629-1:2016 pdf free download.Binders for paints and varnishes Determination of hydroxyl value Part 1:Titrimetric method without using a catalyst Liants pour peintures et vernis — Determination de l’indice d’hydroxyle — Partie 1: Méthode titrimétrique sans catalyseur. 8.3 Determination Add 5 ml of ethyl acetate (52) to the contents of the conical flask and shake, if necessary, with gentle warming, until the test portion (LZ) is dissolved. If the test portion is not soluble in ethyl acetate, another solvent may be used. Allow to cool to room temperature, add (5,00 ± 0,02) ml (see Note 1) of the acetylating reagent (5) by means of the microburette or pipette () and fit the reflux condenser (2) on the conical flask. Heat the flask in the heating apparatus (), maintained at (50 ± 1) °C, for 20 mm, shaking every 5 mm. Cool the contents of the flask to room temperature, remove the condenser, add 2 ml of water, replace the condenser and vigorously shake the flask. Add 10 ml of the pyridine/water mixture (&4) from the top of the condenser so as to rinse down the condenser tube. Mix the contents of the flask and allow to stand for 5 mm…