ISO 8130-7-2019 pdf download.Coating powders一 Part 7: Determination of loss of mass on stoving.
The thickness of the coating powder in the dish should be in the same range as the end use application.
5.2 AIr-circulation oven, capable of maintaining temperatures up to 250 °C. The type of oven shall be stated in the test report, as the design of the oven can influence the test result.
5.3 Analytical balance, capable of weighing to 0,1 mg
5.4 Desiccator, containing a desiccant such as dried silica gel impregnated with cobalt chloride. The drying agent shall not interact with the coating powder.
6 Sampling
Take a representative sample of the product under test as specified in ISO 15528.
7 Procedure
7.1 Number of determinations
Carry out the determination in duplicate.
7.2 Test portion
Dry the dish (Sd) in the oven (5.2) at the specified or agreed test temperature (see AnnexA) for 15 miii and allow it to cool to room temperature in the desiccator (SA). Weigh the dish to the nearest 0,1 mg. Then weigh into the dish, to the same accuracy, a test portion of powder (0,5 ± 0,05) g. By gentle movement of the dish, holding the dish with tweezers, spread the test portion evenly over the bottom of the dish.
As a guide, a test portion of 0,5 g of coating powder in a dish of 75 mm diameter shall be evenly spread to cover the base of the dish. The thickness of the coating layer should he in the range of the end use application.
7.3 Determination
Carry out the stoving at the temperature and for the time specified or as agreed (see Annex A).
Place the dish with the powder test portion (see 72) in the oven (52), previously adjusted to the appropriate temperature, and leave it for the specified or agreed period. For rapid heat transfer, place the dish on a metal plate, at the specified oven temperature, in the oven.
NOTE There is a possibility that, with forced air circulation, the powder will be displaced by the fan of the oven. It is therefore recommended that the fan be switched off for a short time at the beginning of the determination or the sample can be covered with a perforated aluminium foil.
When the period of heating is complete, transfer the dish to a desiccator and allow the dish to cool to room temperature. Weigh the dish and stoved test portion to the nearest 0,1 mg and determine the mass of the stoved material.
Any water present in the product under test Is included in the test result. Report the ambient temperature and the humidity during the test.ISO 8130-7 pdf download.