Preparation method and process flow of powder coating

Preparation method and process flow of powder coating

Powder coating is a commonly used type of coating, which has the characteristics of small particles, rich colors and environmental protection. It is widely used in furniture, automobiles, electronic products and other fields. This paper will introduce the preparation method and process flow of powder coating in detail.

There are two methods for preparing powder coatings: physical method and chemical method. The physical method is mainly to grind the solid pigment into fine particles by mechanical methods, and then mix with the resin to form a powdered pigment. The chemical principle is to create pigments through chemical reactions, and then mixed with resin to form powder paint.

First, an introduction to physical method. The preparation methods of physical method mainly include grinding and shearing method, sand  milling method and spray drying method. The grinding and shearing method is to add the pigment and resin into the sand mill, and through the friction and extrusion of the sand mill, the pigment and resin are fully mixed to form a granular powder coating. The sand milling method is to grind the pigment into fine particles by the grinder, and then mix with the resin to form powder coating. Spray drying method is to dissolve the pigment in water, and then spray it into high temperature hot air through the sprayer, so that the water in the solution quickly evaporates, forming granular powder and then mix with the resin to form powder coating.

Next, chemical methods. The main methods of chemical preparation are emulsion method and solution method. The emulsion method is to dissolve the pigment and resin in an organic solvent, add surfactants, and disperse the pigment and resin in the solution through mechanical agitation to form an emulsion powder coating. Solution method is to dissolve the pigment in the solvent, and then add the resin, through heating and stirring to make the pigment and resin fully mixed, and finally through the evaporation solvent, and at last forming granular powder coating.

In the preparation of powder coatings, the process is crucial. In general, the process includes raw material selection, pretreatment, mixing, drying and screening.

First of all, the selection of raw materials is a very critical step. In the preparation of powder coatings, the selection of suitable pigments and resins is an important factor to ensure the quality of coatings. The pigment should have finer particles and good coverage, and the resin should have good adhesion and chemical resistance.

Secondly, pretreatment is to improve the suitability of raw materials. Grinding and filtering of pigments and resins can make the particles more uniform and improve the quality of the paint.

Mixing is then the process of mixing pigments and resins. By mechanical stirring, grinding and other methods, the pigment and resin are fully mixed to form a uniform mixed liquid.

Next, drying is to evaporate the mixed paint at a high temperature, so that it becomes powder. The drying process should control the temperature and time to avoid deterioration or damage to the paint.

Finally, the particle size range of the powder coating is controlled by sieving. Generally speaking, the smaller particle size range of the coating is more conducive to the uniformity and adhesion of the coating effect. Screening equipment can be selected according to the needs of the coating.

In general, powder coating preparation methods and processes are diverse, according to the type of coating and use requirements to choose the appropriate method and process is the key. Through reasonable raw material selection, pretreatment, mixing, drying and screening, powder coatings with stable quality and rich color can be prepared to meet the application needs of different fields.