After the color-coated plate is baked and aged at a specified temperature and a specified time, evaluate its outstanding loss of gloss, discoloration, blistering, cracking, T-bend performance changes, coating anti-shedding performance and cracking changes, etc. Or the pre-professional T-bend treatment color-coated plate is baked and aged, and the process of evaluating the coating's anti-shedding performance and cracking change at the T-bend is called heat-drying test.
The heat resistance dry test has different technical requirements for different test methods:
(1) Heating test of flat sample. Before the test, measure the gloss and chromaticity coordinates of the sample. Then put the sample into the oven and heat it for the specified time, take it out and dry it for 16 hours, evaluate its loss of gloss and discoloration grade according to the GB/T 1766-1995 standard, and take the worst value of the parallel samples as the test result.
(2) Heating test of the sample after T-bend treatment. Prepare the sample as a test sample with specified T-bend value. Like the flat sample, put the sample in the oven, take it out after the test, and evaluate the loss of light and discoloration grade at the T bend of the sample according to the GB/T 1766-1995 standard, and take the worst value of the parallel sample test results.
(3) After the sample is heated, it is put into the furnace for testing like the flat sample. Prepare no less than 3 samples, leaving one as a control sample after the test. The rest are tested in the furnace like the flat samples. After the test, take them out and do the T-bend test together with the control sample, and then evaluate the change in the T-bend value of the sample after heating and aging, and take the worst value of the parallel samples as the test result.
