The non-volatile content of the paint is the ratio of the weight of the residue after the paint is heated at a certain temperature to the weight of the sample after dry operation, expressed in terms of fractions. Also known as the solids content of the coating. There are two methods of determination: infrared lamp method and oven method.
The infrared lamp method is to fix the lamp on an iron frame and hang it in a square box surrounded by white iron plates. The bottom platform is covered with asbestos and a self-iron plate, and the temperature of the lamp is controlled by a voltage regulating transformer. The sample to be measured is placed under the light with adjusted temperature, stirred continuously, dried until nearly dry, cooled, and weighed until constant weight. It is characterized by higher temperature and faster determination speed. For products that are easy to decompose due to high temperature, it is advisable to use the oven method. For the same product, when the oven method is used to measure, a lower temperature can be used than the infrared lamp method, and the temperature distribution in the oven is uniform, and a large number of parallel inspections can be carried out at the same time. In order to improve the accuracy of the determination by the oven method, crystallization can be added to the sample to prevent skinning on the surface of the sample and oxidation of the paint base.
