Coating powder storage stability testing

(1) Definition

Storage stability refers to the ability of the powdered material to maintain its original physical or chemical properties without agglomeration after being stored under special conditions.

(2) glass bottle method

①Equipment

Glass cup: capacity l21, inner diameter 40mm

Balance: Sensitivity 0.1mg.

Oven: It can keep warm at 50℃±0.5℃.

In addition, there are aluminum small plates, steel shot (ball) and so on.

②Test steps

a. Weigh 45g (or another specified mass) of powder coating, pour it into a glass bottle, place a small plate made of aluminum sheet on the powder coating, and prepare a sufficient number of glass bottles to determine their paintability and other properties to be tested.

b. Weigh 150g of steel shot (ball) into a small plate made of pins in the bottle, seal it, and place it in a constant temperature oven at 50°C±0.5°C.

c. After the specified time, check the agglomeration of the powder coating and the appearance of the coating after spraying.

The storage stability is determined by the time required for the powder coating to not agglomerate and the appearance of the coating film to remain unchanged.

In addition, after the powder is added to the glass bottle, the small plate and steel shot (ball) of the aluminum sheet phase are not added, and they are tightly matched and placed at the specified temperature (any temperature between 40~50°C)

Under the constant temperature oven. Then check the method of agglomeration and the appearance of the coating film after spraying.

(3) Spatial dish method

①Equipment

The temperature of the constant temperature and Humidity Chamber can be controlled at 40°C±3°C, and the humidity is 95%±5%.

Balance: Sensitivity 0.lmg.

Aluminum disc: 50mm in diameter.

Gel time measurement definition.

②Test steps

a. Weigh 10g of powder, pour it into an uncovered aluminum plate with a diameter of 50mm, and place it in a constant temperature and Humidity Chamber at 40°C±3°C and 95%±5% relative humidity.

b. After leaving for one hour, check the powder agglomeration and the change of gelation time to determine the storage stability

c. According to the measurement data, determine the storage stability of the powder.