According to different sampling methods, the preparation methods of interior and exterior paint coating test panels can usually be divided into mass method and volume method. In practice, mass method is mostly adopted and volume method is rarely used.
The specific operation steps of the mass method are: according to the amount of painting specified in the paint product standard, calculate the required sample mass (g) per square decimeter. Then, put the sample into a small container (generally use a beaker), and weigh it together with the brush on a balance with a sense of o.o1 g. Use the brush to dip the sample to paint the model, weigh the brush and the remaining sample together after use, and use the same method to paint the second coat, so that the amount of paint used in the two coats before and after is equal to the amount specified in the product standard.
When painting, brush carefully along the long side first, then along the short side, and finally along the long side to make it a uniform coating film. Unless the product has special requirements, generally two coats should be brushed, and the interval between the two coats should be in accordance with the product regulations. If there is no product specification, the interval between the two coats should be at least 4 hours. After brushing, the test panel shall be placed horizontally on the test bench with the coating facing upwards. Place the sample for 7 days according to the standard conditions stipulated in the state regulation of the relevant paint sample and the sample temperature and humidity standards.
肖新颜;吴祥燕;张会平;万彩霞 - 《化工新型材料》