Types of powder coating
There are two main types of powder coatings: thermoplastic and thermosetting. Typically, buyers and manufacturers will study the total cost and potential complexity of coverage when determining which type is best for their application. There are many subgroups in both categories, and each powder is designed for a specific finish.
Thermoplastics are synthetic materials that can be formed many times. Thermoplastics can melt at high temperatures, which is useful for their reforming and processing, but it is not an ideal choice for parts that may be heated strongly. However, some thermoplastics are preferred as powder coatings because of their abrasion resistance and chemical resistance.
Nylon powder coating is very durable and impact resistant. It has excellent protection against chemicals and solvents, and has been approved by the FDA for contact with food. Parts coated with nylon include food processing baskets and dishwashers. Nylon also has a low coefficient of friction, so it can be used as a coating for gears and conveyor equipment.
Polyvinyl chloride powder coating (PVC)
PVC coating has good flexibility, smooth and durable. Like nylon coatings, they have received FDA food contact approval and can be used in many similar applications. They are also excellent electrical insulators for wires and can be used well as coatings for closed chain links. Greenpeace and other environmental organizations advocate stopping production of PVC due to harmful by-products, but testing on this matter is inconclusive.
Polyolefin coatings have significant abrasion resistance and chemical resistance, and have smooth surfaces and excellent adhesion. Because of these advantages, polyolefin coatings are used on laboratory equipment components that require regular cleaning.
Polyester powder coating
Polyester coatings can withstand weather conditions, have a beautiful appearance, and are resistant to abrasion. They can be used in outdoor furniture, open car parts (for example, steel plates and springs), and are available in a variety of colors. Certain polyester powders are certified for building structure and can be used on the exterior of buildings because they can mask elements and retain their color, and can remain for years with slight fading.
The coating method of thermosetting powder coating is the same as that of thermoplastic powder. Unlike thermoplastics, thermosetting materials undergo chemical cross-linking reactions, which are irreversible during the baking process. This cross-linking changes the physical properties of plastics, usually making them hard coatings. Some thermoset materials can withstand temperatures in excess of 1000 degrees Fahrenheit and can compete with the best high-temperature enamel coatings. Thermosets are harder than thermoplastics, and as some of these thermosets harden, they also become brittle, especially in thick layers.
The surface of the epoxy coating is solid and electrically insulating. However, they are fragile, and when exposed to ultraviolet light (existing in the sun), they form chalk and dullness over time. This defect causes most epoxy-coated items to be used as pipe coatings indoors or underground.
Epoxy polyester hybrid
Adding polyester to the epoxy resin makes the soft plastic less likely to break or crack. Usually referred to as "hybrid" coatings, they work better outdoors than pure epoxy resins, showing lower fineness and better weather resistance. In terms of impact resistance and durability, their properties are similar to pure polyester. Their uses include office furniture, fire extinguishers and toys.
Acrylic powder coating
Unlike epoxy resin, acrylic can cope well with sunlight and mix on the surface, leaving a smooth, moist appearance, transparent or colored. At present, due to their insufficient brittle hardness and strength, they are still used as automotive transparent coatings. However, acrylates are widely used in certain automotive parts, such as wheels and open engine parts, and car owners want to obtain super-gloss surface treatment.
The high-temperature powder is composed of silicone resin, curing catalyst and glass filler. They are used as car and motorcycle parts as well as oven racks and