Types of Car Paint

Types of Car Paint

According to the different objects and requirements of automobile painting, automobile paint can be divided into two types: original paint and repair paint.

01. Original paint

Original paint: the paint used in the production line of the automobile factory. This type of paint only produces a chemical reaction at a temperature of 120°c - 160°c for 20 - 30 minutes to form a paint film.

The car paint used in the original factory paint is a baking polymerization type paint, which is baked at a certain temperature to make the functional groups in the molecules of the film-forming substance undergo a cross-linking reaction and cure.

02. Refinish paint

Automobile repair painting refers to the surface that has been repaired by sheet metal and processed to meet the requirements of the original paint. Since the automotive interior parts and other parts have been installed in place at this time, the process requirement of the original paint is to bake at a temperature of about 200 degrees. Considering the safety and reliability of the repair coating process, the raw materials used in the paint repair coating process are basically two-component (ready-to-use, ready-to-use, and the use time is strictly limited), and the process adopted is room temperature curing Or bake forced curing process.

Repair paint can be divided into solvent volatilization type, oxidative polymerization type and curing agent reaction type according to the paint film forming method.

01. Solvent volatile paint

The solvents used are mixtures of several solvents and co-solvents. When determining the proportion of solvents, in addition to considering the solvent’s ability to dissolve the resin, toxicity, flash point, economy and other factors, attention should also be paid to the volatility of the solvent. If the volatilization is too fast, the paint film will easily have defects such as pinholes and orange peel due to the rapid increase in viscosity; if the volatilization is too slow, the paint film will easily sag and affect the drying speed of the paint film.

02. Oxidation-polymerization coating

In oxidation-polymerization coatings, in order to accelerate drying, a certain amount of catalyst is usually added. It is generally believed that the lead catalyst is effective in promoting the polymerization reaction of the inner layer, and the cobalt and manganese catalysts are effective in promoting the oxidation-polymerization reaction of the outer layer of the coating film. When determining the type and amount of catalyst, it should be reasonably selected according to the drying conditions of the coating film and the oil content in the coating. For oxidation-polymerization coatings, the temperature is high, the solvent volatilizes quickly, and the oxidation-polymerization reaction also proceeds quickly. Humidity is high, even if the temperature is high, it is not as good as drying under the condition of low temperature and low humidity.

03. Curing agent film-forming coating

Curing agent film-forming coatings are cured by cross-linking material molecules caused by active groups in the curing agent. Epoxy auto paint clear coat with H-1, H-2 and other curing agents can be cured at room temperature, while acid anhydrides and some amines as curing agents need to be baked and heated to cure. In order to shorten the construction period and improve the performance of the coating film, the coatings cured at room temperature can sometimes be cured by heating.

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