Powder coating is a dry color coating process that has become extremely popular since its introduction over in the 1960s. Many companies make a choice of powder coatings for a high-quality, durable finish, allowing for maximized production, improved efficiencies, and simplified environmental compliance. powder coatings are available in an almost limitless range of colors and textures, and technological advancements have resulted in excellent performance properties.
Powder coating is a type of coating comprised of solid raw materials such as resin and does not contain any solvents. All powder coating raw materials such as pigments, hardeners, fillers, and additives are in solid form and these materials are homogenized by being mixed together. A process called electrostatic spray deposition (ESD) is typically used to achieve the application of the powder coating to a metal substrate. This application method uses a spray gun, which applies an electrostatic charge to the powder particles, which are then attracted to the grounded part. After application of the powder coating, the parts enter a curing oven where, with the addition of heat, the coating chemically reacts to produce long molecular chains, resulting in high cross-link density. These molecular chains are very resistant to breakdown. This type of application is the most common method of applying powders. Powder coatings can also be applied to non-metallic substrates such as plastics and medium density fiberboard (MDF)
Powder coating provides both environmental and economic benefits over traditional liquid paints. Liquid paints contain up to 50% solvent to dissolve and apply resins and pigments. Solvent vapors in the athmosphere has a significant risk on environment. The powder coatings are eco-friendly as they emit zero or near zero solvents that are known to produce volatile organic compounds (VOC).
Powder coating is an easy to use, operator friendly and eco-friendly process. Powder coating is simpler to apply than conventional painting systems. It does not create problems such as leak, dripping and collapse.
It is in the interest of the company to work with experienced and trained qualified personnel in terms of quality control criteria, customer satisfaction, coating film thickness and corrosion resistance in terms of the foolproof operation of the process flow system.
The surface cleaning systems of wet paint and powder paint before painting are also the same. A well-made wet paint system and a powder paint system occupy the same space.
Surface cleaning is as important in powder paint as it is in wet paint. Cleaning and phosphating the material to be painted or chromating it for aluminum increases the perfection of paint quality.
Powder Coating technique is easy and user training can be done in a very short time.
• Solvent-free
• Reduced risk of fire
• Lead-free
• Ease of waste disposal
• No hazardous materials used during clean up
• No Volatile Organic Compounds (VOC)
• Contain no toxic heavy metals such as lead or chromium (VI)
• No paint sludge from a spray booth
• High Application Efficiency; recyclable, up to 99% usage, overspray can be reused
• Improved productivity
• One coat system, simple process
• Can build high film thicknesses easily, up to 150 microns with one coat
• No costly removal and reprocessing of solvents
• Highly durable
• Low carbon footprint
1. Electrostatic spraying (gun) method: Powder particles are liquefied with air and carried to the spray guns, where they are charged with 10150 kV or with friction (tribo) in Corona type guns. The charged powders adhere to the grounded surfaces. Powders, which cannot adhere to the surface and fall down, are collected by ventilation systems and filtered. Then, they are mixed with powder and used again. There are 2 types of charging/guns which allow this method to be applied. The types of guns used in the electrostatic spraying method and their features can be listed as follows:
CORONA Charging can be controlled thanks to the electrical current. All types of powder of all thicknesses are used. Environmental factors such as temperature and humidity have fewer effects. Guns and operating costs are low. The Faraday cage is formed. The film thickness can change with a voltage adjustment. High consumption. Powder replacement (system cleaning) is easy. High risk of back ionization.
TRİBO No need for high voltage. The powder is charged with friction. Special particle sized and tribo designed powders are used. Easily affected by environmental factors. High cost. No Faraday cage effect. The film thickness may vary with air adjustment. Low consumption. Difficult powder replacement. Low risk of back ionization.
2. Dipping method: Powder coatings can also be applied by dipping into a fluidised bed of powder, made to flow like a liquid by bubbling air through it. The biggest disadvantage of this method is that it is difficult to adjust the coating thickness. Due to very thick surfaces, powder consumption and the total usage cost is high. Although this is not a widely used method, it can be used for functions, such as coating small parts for which using a gun is difficult.
The formula contains an epoxy-type resin and a suitable hardener. It is used when resistance against chemicals is desired. Particularly, fuel tanks can be shown as an example. These types of powders have less resistance against heat and light. It is also used as a primer when high corrosion resistance is required.
It contains epoxy and polyester resin. It is a powder type developed to provide physical and chemical resistance properties together. It is used indoors. It is particularly an inevitable solution for the white appliances industry. Moreover, home/office lighting fixtures, metal furniture, hospital equipment, towel warmers, radiators, armatures, and shower cabins can be coated with this type of powder. Although it is stronger than epoxy type powders in terms of heat and light resistance, it has less resistance than outdoor polyester powders which we will discuss later.
Polyester/TGIC: It contains a polyester resin and TGIC hardener. It is an exterior wall powder. It is especially recommended for aluminum window and door profiles. When properly designed and used, it can withstand sunlight and other climatic conditions for 10 years. It is mainly used in the aluminum profile industry, agricultural machinery, bicycles, rims, lighting fixtures, etc.
Polyester/Primid: It contains a polyester resin and primid hardener. It is an exterior wall powder. It is used for exterior walls, where loss of color and brightness is undesirable, and especially for architectural applications. It is recommended for aluminum window and door profiles. When applied properly, it can withstand up to 1015 years depending on the climatic conditions like other PT. TGIC-containing products have to receive certain labeling marks according to European Union norms while primid products do not have any marking. PRIMID, which is widely used especially in the European market, is the strongest competitor of TGIC.
Its formula contains a polyester resin and suitable (isocyanate) hardener. It is highly resistant to abrasion, moisture and salt spray test. (Compared to other polyester exterior wall products, it provides chemical resistance as well as UV resistance.) It can be used in automotives, bathroom accessories and garden products.
It is particularly preferred in the automotive industry. These are very strong and durable powders. However, they are not produced in the facilities where other types of powders are produced due to the incompatibility with other types of resins and contamination. Therefore, this product is not included in the Pulver Kimya product range.
Routine maintenance is important for high operating quality and low operating costs.
Ovens should be measured seasonally and optimized as needed.
Good grounding is necessary for homogeneous dyeing and less recycling.
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