The composition of car refinish paint:
Car refinishing paint refers to the paint used to re-repair the original paint of the car body. It can only be operated manually by workers, and spraying must be operated at low temperature (below 60 degrees Celsius).
Refinish paint must have two functions: protection function and aesthetic function. These two functions cannot be performed independently by a single product. Therefore, high-quality refinish paint brands generally have a series of products to combine, which mainly include: (1) Putty: used to fill sheet metal defects. (2) Primer: used to prevent rust, promote adhesion between paint layers and increase the thickness of paint film. (3) Top coat: used to improve surface quality and increase weather resistance. In view of the fact that the entire automobile cannot withstand high-temperature baking, the painting conditions of general automobile repair factories are poor. Auto refinish and refurbishment coatings mostly use self-drying primers, putty, intermediate coating, self-drying synthetic resin paint and volatile drying nitrate Base paint, per chlorovinyl paint. Nitro paint is easy to apply, quick-drying, and can be polished. It is an ideal topcoat for car repair. However, the weather resistance of general nitrocellulose paint is poor. In the south, it can lose gloss and change color severely in one summer. Nitro paint modified with high-quality resins (acrylic resins and silicone resins) has better weather resistance. But its solid content is low, it needs to spray 3~4 times to reach the required surface coating thickness, and the price is more expensive, so the repair cost is higher. Alkyd paint has better weather resistance. Generally, the thickness of two sprays can reach more than 40um, and the gloss and fullness of the coating are better. The disadvantage is that it dries slowly, each paint needs 16~24h to dry by itself, the construction period is long, and a cleaner painting environment is required. In addition, alkyd paint has poor heat and humidity resistance, is easy to foam, and has poor appearance and decoration. It is not suitable as a top coat for automobiles. At present, most paints are made of double-layer paint, that is, a metal layer or a pearl layer and then a varnish, and the rest is basically a two-component pure color paint. The two-component paint was first introduced by Akzo Nobel Xinjin in the 1960s. Its basic mechanism is to use the hydroxyl functional group (-OH)-containing acrylic chain and the (-NCO) group in the cyanate ester. The group reacts and cures into a polyurethane polymer with a network structure. This two-component polyurethane paint has the advantages of nitrolacquer alkyd paint. The coating film is fast-drying, gloss and fullness are good. It can reach a thickness of more than 40um after one or two coats. It has weather resistance, chemical resistance and resistance. It has excellent heat and humidity properties and was quickly adopted by various paint manufacturers.
Metal paint and pearl paint use modified butyl acetate cellulose resin as the carrier, and then covered with a layer of transparent two-component varnish.
