ISO 8130-7:2019 pdf free.Coating powders一Determination of loss of mass on stoving.
3 Terms and definitions
For the purposes of this document, the specific terms and definitions given in ISO 8130-14 apply.
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4 Principle
A test portion of the powder is placed on a dish and then stoved (heated). The loss of mass on stoving is calculated from weighings before and after stoving.
5 Apparatus
Ordinary laboratory apparatus, together with the following:
5.1 Flat-bottomed dish of tinpiate or aluminium, approximately 75 mm in diameter.
The dimensions of the dish are not critical, but the base shall be flat to ensure good thermal contact and to permit the test portion of the coating powder to be spread to a thin, even layer. The thickness of powder can have a significant influence on the test result.
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 (S2) at the specified or agreed test temperature (see Annex A) for 15 mm 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 be 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 (5.2), 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.