Automotive paint is mainly composed of resin, pigment, additives, filler, curing agent, solvent, etc.

A resin (film forming material)

B pigment (including body pigment, anticorrosive pigment and coloring pigment)

C solvent

D additive

A. Resin can be divided into: natural resin; synthetic resin (including: thermoplastic, thermosetting, self crosslinking type)

1. Description of natural resin: secretions from insects or trees. Ingredients: rosin, shellac

2. The thermoplasticity of synthetic resin shows that it softens at high temperature and is easy to be solvent.

Ingredients: vinyl resin, cab cellulose acetate butyrate, nitrocellulose.

3. The thermosetting property of synthetic resin shows that it is not easy to soften when heated, with high hardness and solvent resistance.

Ingredients: melamine, epoxy resin, acrylic resin.

4. The self crosslinking type of artificial synthetic tree indicates that chemical reaction occurs and solidifies when two components are mixed.

Ingredients: unsaturated resin, polyester resin, polyurethane resin.


B. pigment classification: anticorrosive pigment ,physical pigment ,coloring pigment (inorganic pigment and organic pigment).

1. Anticorrosive pigment: widely used as primer to enhance anti-corrosion effect.

2. Body pigment: improve film thickness and abrasiveness, is the main pigment used in primer and other coatings.

3. Coloring pigment: provide color, color and covering power. (inorganic pigments refer to metallic oxides, usually gray colors. Such as titanium dioxide, iron oxide red and other pigments. Organic pigments refer to: mainly bright colors, but poor coverage, such as phthalocyanine blue, adipic red and other pigments)

C. Auxiliaries: compounds with various special properties. Usually a small amount is added to the paint to obtain or improve the special properties of the paint, but the maximum proportion in the paint is not more than 5%.

The types of additives are: dispersant, defoamer, curing accelerator, anti shedding additive, softener, anti-corrosion additive, leveling agent, anti sedimentation agent, UV absorber, antioxidant, anti pinhole agent, etc

Important role of auxiliaries:

Additives for paint is very important, because any color of things in the sun may fade, car paint is also the same, its pigment in the sun will fade, at this time, the paint with additives is very important. For example, ultraviolet absorbents, antioxidants, etc., together with these additives can prolong the fading time and prevent premature aging of the paint. In many cases, the quality of the paint depends on the quality of the additives to a certain extent.

D. Filler: refers to the body pigment, used in primer to improve the film thickness and abrasiveness.

E. Curing agent: used for self crosslinking resin. It can be cured by chemical reaction when two components are mixed.

F. Solvent: liquid with many uses. It can dissolve the resin, adjust the viscosity, make the pigment and resin mix more easily, ensure that the paint has the construction viscosity, and can also be used to clean the spray gun to clean the extra paint stuck to hands and objects.

Painting process

Car paint is generally baking paint. In the car factory, after the frame and shell are welded (sometimes repaired by hand), the next process is painting. Generally speaking, the first is the primer. Immerse the bare car shell into the syrup like paint tank, take out the drying primer, and then send it to the dust-free workshop to spray the top paint with electrostatic spraying process. Then dry it at about 200 degrees. More elegant, but also on a layer of varnish. In this way, the painting process is finished. There are several kinds of general topcoat: ordinary paint; metallic paint; pearlescent paint. Ordinary paints, needless to say, resins, pigments and additives. There's more aluminum in the metallic paint; so it looks bright when finished. For pearlescent paint, mica particles are added. Mica is a very thin piece of things, so the reflection direction, there is a colorful effect. If it's metallic paint and varnish layer, the car's paint looks very bright and beautiful. In terms of color, white is undoubtedly the cheapest. For example, the world-class brand red pigment is about 25 times more expensive than the world-class brand titanium dioxide; and the amount of titanium dioxide in white paint is about five times that of red pigment. As a result, the cost of red paint on color is five times higher than that of white paint. That's why some domestic cars have so few colors: simple and low cost.