What is meant by powder coated?
Powder coating is a dry finishing process. As functional (protective) and decorative topcoats, powder coatings have an almost limitless range of colors and textures, and technological advancements have resulted in superior performance.
In this process, the paint is electrostatically applied to the item and then cured by heat. Powder coatings have a harder and stronger finish than conventional coatings.
Outperforms other coating processes.
- Powder coatings are solvent-free and emit little or no volatile organic compounds (VOCs) into the atmosphere.
- Powder coatings can produce thicker coatings than traditional liquid coatings without sagging or sagging.
- The difference in appearance of powder coated articles is generally small compared to liquid coatings between horizontal and vertical coating surfaces.
- The use of powder coating can easily achieve a variety of special effects that cannot be achieved with other coating processes.
- Powder coatings cure significantly faster than liquid coatings, especially when using UV-cured powder coatings or advanced low-bake thermoset powders.
Advantages of Powder Color Coated Sheets: Ultra-Thick Coatings.
1) Conventional products: single-sided coating 45μm; double-sided coating 45μm/25μm.
2) High demand products: single-sided coating 50-100μm; double-sided coating 50-100μm/25-45μm.
3) Products with special requirements: single-sided coating 80-300μm; double-sided coating 80-300μm/50-80μm.
Powder color coating process:
① Uncoiling → ② Riveting → ③ Entry looper → ④ Pretreatment → ⑤ Powder electrostatic coating → ⑥ Curing → ⑦ Water cooling and air drying → ⑧ Exit looper → ⑨ Inspection → ⑩ Coiling → Packaging.
Powder coatings are based on polymer resin systems combined with additives such as curing agents, pigments, leveling agents, flow improvers, etc. These ingredients are melted, mixed, cooled and ground into a homogeneous powder similar to baking flour. A process called electrostatic spray deposition (ESD) is commonly used to apply powder coatings on metal substrates. The application uses a spray gun to apply static electricity to powder particles, which are then attracted to the grounded part. After the powder coat is applied, the part enters the curing oven. In the heating furnace, the coating undergoes a chemical reaction to create long molecular chains, resulting in a high crosslink density. These molecular chains are very resistant to decomposition.
Painting powder coated aluminum.
When working with powder coated surfaces, priming is an important part of the process of repainting. Select a primer appropriate for the alloy in question, whether aluminum or steel. After the first attempt at sanding, use the primer to test the adhesion level of the area. Apply a small spot of primer and allow to dry for 20-30 minutes. Attempt to wipe the spot off. If it wipes off, or smears, it is an indication that there is not enough adhesion to continue. After sanding to remove the powder coat, the bare area will need a full coat of the primer to allow the paint to adhere. Consult a professional for the proper primer for the project.
Selecting the right paint for the job is essential when painting over powder coat. Even with the right primer, certain paints may not adhere completely. Epoxy-based paints will stick to most surfaces, but may be costly and limited in the colors available. Enamel paints may be a better option cost-wise and should adhere well to primers needed for metal alloys.