Plastic powder coating process overview and product selection

Plastic powder coating process overview and product selection

Plastic powder coating is a method of coating the surface of a substrate with a powder material, heating it to a fluid state, and then curing over the surface of the substrate to form a protective or decorative coating. Powder coatings have many advantages over traditional liquid coatings, such as better environmental performance, thicker coating can be obtained in one painting, and a variety of styles.

Powder coating is still more complex in some aspects, and it is necessary to select appropriate products and coating processes according to different needs. So how to do powder coating?

1, powder coating steps

1.1 First determine the type of substrate to be coated. Powder coating is divided into thermoplastic type and thermosetting 2 kinds, need to choose the right powder coating according to different substrates, in order to achieve the best painting effect.

1.2 Before painting begins, remove all threads or lubricating interfaces and all parts that do not need painting. It sounds simple, but many people forget this step. The powder coating will adhere to everything, including screws, nuts, bearings and other parts that do not need to be painted.

1.3 Clean the metal surface thoroughly. Use shot blasting or sand blasting to treat cemented carbide to remove surface dirt and rust. Use chemical solvents to clean the grease and coating on the surface, and can be polished. If desired, aluminum, magnesium and other soft metal alloys can be cleaned with a solvent and polished with a wire brush.

1.4 Apply the powder coating on the surface of the substrate. The charged powder coating is attached to a grounded substrate surface by using a spray gun or compressed air sprayer, which can be priced as low as $100, depending on the supplier. In the experiment, the powder can be sprayed directly on the surface of the metal plate.

1.5 Select the appropriate temperature to cure the powder coating attached to the substrate. Oven can be used for curing, generally can be applied to the size of relatively small metal substrate, large substrate can also use infrared or other flameless heat source curing method. Normally, the object is heated to 175 ~ 190 ° C, about 10 ~ 15min, and then cooled.

2, the difference between thermoplastic powder coating and thermosetting powder coating

2.1 Thermoplastic powder coatings can be remelted and cured, while the coating of thermosetting powder coatings cannot be remelted and cured after curing, which is the most obvious difference between the two.

As the name of both, the reason that thermosetting powder coatings cannot be recurable is that irreversible chemical reactions occur, in contrast to thermoplastic powder coatings, no chemical reactions occur during the curing process.

2.2 The choice of coating depends on the characteristics of the substrate to be coated. Thermoplastic and thermosetting powder coatings are used on different substrates due to different chemical properties.

Thermosetting powder coatings: can enhance the integrity of the substrate, suitable for the substrate will be heavily worn, and can provide chemical and heat resistance.

Thermoplastic powder coatings: can provide strength and flexibility, commonly used in plastic and mechanical parts.

2.3 Advantages and disadvantages of thermosetting powder coatings. General thermosetting powder coatings are used on heat-resistant substrates.

Advantages: beautiful coating; Low cost; The coating has good stability and heat resistance.

Disadvantages: The irreversible curing process means that the coating cannot be recovered and is difficult to be cured by secondary melting.

2.4 Advantages and disadvantages of thermoplastic powder coatings. Thermoplastic powder coatings are commonly used on plastic and durable substrates such as park benches, but are also widely used on metal pipe exterior surfaces.

Advantages: high lubricity; Able to re-melt solidification; Increased impact resistance

Disadvantages: Generally high cost; Heat may melt.