1 Definition, Purpose and Significance
2 Relevant standards
GB/T 1761-79(89) Determination of paint film anti-fouling properties
3 Introduction to key points of inspection methods
3.1 Test Principle
Determine the changes of the paint film surface caused by C0, C02, S02, N02 and other pollutants under different drying degrees of the paint film.
3.2 Materials and equipment
Broken glass shades, wire beams, kerosene lamps, tinplate, anti-pollution gas Testers.
3.3 Operation points
Divide the surface drying time of the sample into five stages, and divide the three tinplate plates into four grids. In every 1/5 interval time, the samples to be tested are placed in a grid with the French brush in turn, and the temperature and temperature are kept constant. Under wet conditions, until the fourth grid is painted, and then placed for 1/5 of the interval, move the sample on each layer of the wire rack. Light the kerosene lamp and calibrate the size of the flame to a height of 2 cm, and cover the glass cover with a rubber pad ground on the bottom to make it airtight. The flame in the cover should extinguish itself within 4 minutes, and the sample is in the cover. Keep it for 30 minutes, take out the model to observe the change of the paint film. (Related instrument: drying time Tester)
The test can also be carried out in an airtight box, s02 can be supplied by gas cylinders or gas generating equipment, and equipped with suitable regulating and measuring equipment. S0 is generally recommended when the test coating does not exceed 40 µm. Since the dry s02 is not very corrosive, the test needs to be carried out under certain temperature and humidity.
The S02 injected into each test cycle is the same volume, so the total area of the test in the box is an important condition, because the rate and degree of absorption of S02 by different types of paint films are different, so the test conditions will be affected by the box. Influence of test plate type.
In order to make the test closer to the actual situation, the s02 (or NH3) test is also combined with the artificial accelerated aging test to simulate the outdoor environmental conditions of the chemical plant, so that the test results are more consistent with the actual application.
3.4 Result Judgment
Those with smooth surface of the paint film are qualified, and those with silk lines, wrinkles, netting, loss of gloss, and many spots in any one grid or part are unqualified.
