1 Composition of matt varnish

In addition to resins and additives used in traditional varnishes, matting agents are an important component of matt paints. At present, the matting agent can be divided into inorganic and organic two types, which belong to the filling type, such as rustic phase SiO2, algae and silin, with significant matting effect; later, it is floating type, such as sponge, with weaker matting effect, but anti-blocking , It is effective in scratch resistance and can effectively prevent the matting agent on site. In the process of matt varnish recovery, the physical properties of wax can be combined with SiO2, and the surface treatment can be performed with wax to effectively extinction at the same time.

2 Reaction of matt varnish

In the wet state, the SiO2 matting agent is evenly distributed in the coating film. Along with the necessities, a layer of film can be coated under the light, and the surface is coated with uneven state, the effect of the film is reduced.

3 Construction technology of matt varnish

1), Masking. In order to reduce the amount of repair work, it is necessary to avoid defects such as particles as much as possible at the source. Before spraying, it is necessary to cover the interior of the car body with a plastic film to avoid blowing the dust from the previous polishing process to the car body in the oven.

2), Dust removal. For matt varnish, dust removal is a very important link. Generally, electrostatic dust removal guns are used to clean the entire vehicle, and then the entire vehicle is wiped with absolute ethanol and a cleaning cloth.

3), the first spray. The total film thickness of the matt varnish must be at least 40μm. In order to ensure the workability and quality of the coating film, the spraying needs to be divided into two times; the spraying pressure needs to be adjusted according to the nature of the coating and the site conditions.

4), Leveling after the first spray. After the first spraying, it needs to be leveled for 10~15min to ensure that the matting powder has been fully and evenly arranged. For manual spraying, the operation stability is more difficult to control. If the second spraying is performed directly without leveling, uneven gloss is likely to occur.

5), the second spray. The operation method is the same as the first time.

6), Leveling after the second spray. The leveling time is 15-20min, but not more than 25min. Within 15~20min, the car body is in a state close to matt but not full. After more than 25min, the leveling time is too long, which will cause the feel to be too rough and increase the working hours. Therefore, in order to balance the gloss and touch, it is not advisable to level it for too long.

7), Bake. Low-temperature baking, 80°C, 60min is used on site. After baking, the two-component mixing system should be cleaned within 1h to avoid the solidification of the curing agent in the pipeline and cause blockage.

4 The main factors affecting the extinction effect

1), resin film-forming material

2), the particle size of the matting agent

3), the degree of adjustment of the matting agent

4), the degree of dispersion of the matting agent

5), coating film thickness