Powder coating is a type of coating that is applied as a free-flowing, dry powder. The main difference between traditional liquid paint and powder coating is that the powder coating does not require any solvent to keep the bonding agent and the filling materials in solution and then subject to heat treatment for making it possible for it to flow and the “skin” to be produced. The powder is thermoplastic or thermosetting. In most cases it is used for creating a surface harder than with traditional paints. Powder coating is used mainly for coating metals; these may include drum fittings, car parts, bicycle parts, household appliances, etc. Owing to the newest technologies, we can powder coat other substrates as well, for example also fibreboard of medium density.
During the powder coating, the paint is applied in the form of free-flowing, dry powder. Contrary to the traditional paint, powder coating does not require any bonding agent, filling materials and solvent. The substrate is coated then heat treated in order to form the surface. The powder is thermoplastic.
There are two main categories of powder coating: thermosets and thermoplastics. When the powder is baked, it reacts with other chemical groups in the powder to polymerize, improving the performance properties. The thermoplastic variety does not undergo any additional actions during the baking process as it flows to form the final coating.
The powder coating process involves three basic steps:
Removal of oil, dirt, lubrication greases, metal oxides, welding scale etc. is essential prior to the powder coating process. It can be done by a variety of chemical and mechanical methods. The selection of the method depends on the size and the material of the part to be powder coated, the type of impurities to be removed and the performance requirement of the finished product.
In many high end applications, the part is dried following the pretreatment process, and subsequent to the powder coating application. This has been particularly useful in automotive and other applications requiring high end performance characteristics.
Another method of preparing the surface prior to coating is known as abrasive blasting or sandblasting. Blasting abrasives are used to provide surface texturing and preparation, etching, finishing, and degreasing for products made of wood, plastic, or glass. The most important properties to consider are chemical composition and density; particle shape and size; and impact resistance.
Cast steel shot or steel grit is used to clean and prepare the surface before coating. Shot blasting recycles the media and is environmentally friendly. This method of preparation is highly efficient on steel parts such as I-beams, angles, pipes, tubes and large fabricated pieces.
Different powder coating applications can require alternative methods of preparation such as abrasive blasting prior to coating.
Powder coating has high quality; it can even be used for several thousand products. The powder coat protects both the most rigid, heavy machines and the small household appliances used daily. It provides more durable surface than liquid paints, at the same time it has much better make. Powder coated products have better resistance to impact, moisture, chemical agents, ultra viola light, and other extreme weather conditions. Owing to the powder coating, the risk of scratches, wear, corrosion, discolouration and other problems of wearing will decrease.
Beyond its durability, powder coating is much more attractive selection because of its environment-friendly advantages. Independently of the mode of application, powder coats are easy to handle, environment-friendly, cost-effective and durable.© 2024 - Nyírlift Kft. www.nyl.hu