Methods of test for paints - Tests on liquid paints (excluding chemical tests) - Determination of pigment content by ashing - Part A27: Determination of pigment content by ashing
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 the product under test is ashed. The method is not applicable to coating materials containing aluminium, organic pigments and/or dyestuffs, or inorganic pigments treated with organic compounds. Such constituents, which could make up about 10 % of the pigment, will be lost during ashing.
As the state of many pigments and extenders changes under the specified test conditions, it will depend on the composition and the chosen ashing temperature whether the actual pigment content of the product under test can be deduced from the apparent pigment content found by this method.
The method is generally not suitable for UV paints and varnishes or those containing reactive diluents requiring special heating conditions.
The pigment content of coating materials can also be determined by a centrifuge method (see ISO 14680-1) or by a filtration method (see ISO 14680-3).