Methods of test for paints - Tests on liquid paints (excluding chemical tests) - Determination of pigment content by filtration - Part A28: Determination of pigment content by filtration
This part of ISO 14680 is one of a series of standards dealing with the sampling and testing of paints, varnishes and related products.
It specifies a method for determining the pigment content of paints in which potassium hydroxide solution is added to coagulate the pigment and the resulting solids filtered off. The method is particularly applicable to coating materials containing carbon black, very finely divided silicon dioxide, very finely divided titanium dioxide, organic pigments or polymer dispersions. It is not applicable to many water-dilutable paints because the whole binder will coagulate when the potassium hydroxide solution is added.
The pigment content of coating materials can also be determined by a centrifuge method (see ISO 14680-1) or by an ashing method (see ISO 14680-2).