Through the study of color coated plate, a test method for fast prediction of the adhesion aging performance of color coated plate coating was found. Through the systematic analysis of the experiment, it was found that the structure of coating resin, the roughness of substrate, the type of substrate and the pretreatment technology of color coated plate had a great influence on the adhesion aging performance of color coated plate coating. The way to improve the adhesion aging performance of color coated plate coating was put forward. Coating adhesion is an important technical index to evaluate the quality of color coated plate. At present, T-bend test is generally used to characterize the adhesion of the coating.
However, the application experience of color coated plates shows that the adhesion of some color coated plates will rapidly deteriorate with the increase of storage time, which affects the normal use of color coated plates. The most direct performance of the adhesion aging performance of the coating is that the T-bend test results of the coating decrease rapidly with the increase of storage time. The main factor that causes the T-bend performance to decline is the influence of water, oxygen and ions in the natural environment where the color coated plate is stored.
This kind of influence is a slow process, so it will take a certain time for this kind of influence to occur and be shown by T-bend test. This will cause the poor adhesion of the color coated plate after it reaches the user's hands, which will have a negative impact on both the production unit and the user of the color coated plate. In this paper, by accelerating the simulation of the impact of natural environment on the adhesion of coating, a fast and accurate method for predicting the adhesion aging performance of color coated plate coating is obtained.
The change rule of adhesion aging property of different coating systems was obtained by experiment. The factors influencing the adhesion aging property of the coating were studied and analyzed. The way to improve the adhesion aging property of the coating was put forward. Determination of adhesion aging property of coating on color coated plate T-bend test shall be carried out on the off-line color coated plate according to the test method of color coated steel plate and steel strip. Then, the samples were stored in the laboratory for 6 months, and T-bend test was also carried out to obtain the aging performance of the coating adhesion for half a year.
1.2 prediction of adhesion and aging performance of coating of color coated plate T-bend test will be carried out for the off-line color coated plate according to the test method of color coated steel plate and steel strip. Then put the sample into constant temperature and humidity test chamber for 24 h accelerated aging test, the test temperature is 70, and the relative humidity is 95%. The water molecules on the surface of the coating can reach the interface of the coating metal matrix through adsorption, diffusion and infiltration until the interface of the coating / metal matrix is damaged. The initial macroscopic performance of this kind of interface damage may be the decrease of coating adhesion, which is manifested as the poor aging performance of coating adhesion, and the further macroscopic performance is the foaming and falling off of coating. Therefore, the corrosion resistance of the color coated plate can be predicted by the results of adhesion aging test, which has a good early warning effect on improving the quality of color coated plate products.