A Study On The Lifespan Of Pre-Coating Sheet Adhesion

For pre-coating products, with the effects of environmental factors (Such as ultraviolet radiation, oxygen, humidity, temperature etc), the adhesion between the coat and the substrate will be reduced as time goes by. That is so called the lifespan of adhesion.This article made researches on the state of the sample parts surface, and figure out it's effects on the adhesion. It had been investigated that what kind of influence would be created on the performance of organic coated matals by surface pretreatment of metal substrates. From experiments, we found that the coating adhesion would be reinforced by increasing the surface roughness. Further more, the moist efficiency could be improved by enhancing the surface freely energy, and the better moist efficiency the better superficial diffusibility, and finally the adhesion of the sample parts could be enhanced. It would be very usful for painting process.This article investigated the effects of different coatings on the lifespan of adhesion. The epoxy coatings and polyurethane coatings from three different suppliers had been investigaed in this article, and it was found that different coatings would cause different adhesions and lifespans even on the same substrates. The adhesion and lifespan of the polyurethane coating is much better than that of the epoxy coating. In addition, the lifespan of adhesion could be extened by increaing the thickness of the coating.This article made the researchs on the effects of environmental factorson the lifespan of the adhesion. According to the structure of the coated surface, the ideal coating could effectivly prevent outside materials from touching the metal sheet. Actually due to many reasons, such as the restrictions on the process of surface pretreatment and painting, the destory by outside factors like temperature, humidity and ultraviolet during the storing and using, there would always be many pores in the coating, through which the water, oxygen and other materials could contact the the metal substrate. Then the electrochemical corrosion occurred in there, the generated corrosion products fill in the interface between the coating film and metal substrate. The result of this process would reduce the coating adhesion and shorten it'lifespan.