Powder coating has become one sought-after technique for several industries such as appliances, automobiles, electronics, furniture and home decoration. The advantages of powder coating over conventional liquid coatings are several. In addition to the fact that no solvent is required to keep the binder and filler parts together, which eliminates fumes and gases, powder coating can be recycled and reused to almost 100 percent utilization of the material, making the technique environmentally friendly and very cost-effective.
Other advantages include the lower cost of powder lines over liquid ones, and the fact that the overspray can be recycled. Related to appearance, it can be applied in thicker coatings without running, dripping or sagging, vertical and horizontal coated surfaces usually show fewer differences than liquid coated items, and specialty effects can be achieved with no volatile organic compounds.
Vitracoat Pinturas en Polvo S.A. de C.V. recognized those advantages over 15 years ago and found a niche market in Mexico that had little competition. The company started business in 1948 producing liquid coatings for the furniture and automotive industries but at the end of the1980s, it detected a change in customers’ preferences for powder coatings.
The company started producing 150,000 pounds of powder coatings a month in its plant in Mexico City. By 2000, the company had expanded into a second plant, located in Lerma, state of Mexico raising the initial production to 2.4 million pounds monthly. With several additions, the company is currently producing 36 million pounds yearly. In the first quarter of 2007, Vitracoat will launch its first plant and research center in Elkhart, Ind. The American plant will work under the umbrella of Vitracoat America Inc. corporation, a subsidiary of Vitracoat Pinturas en Polvo de Mexico. The new facility in Elkhart will cover the special needs of certain clients and specialty products, while more traditional products will be manufactured in Mexico.
The main manufacturing facility employs over 1,000 employees and covers a surface of 300,000 square feet. With nine warehouses in Mexico, nine in the United States, and several sales offices, the company gathers orders and delivers products to all North American regions, Central and South America.
THE POWDER COATING PROCESS
Powder coating, a dry coating applied as a free-flowing, dry powder, is an advanced method of applying a decorative and protective finish to a broad variety of products. The coating, a mixture of finely ground particles of pigment and resin, is applied electrostatically and “cured” under heat to form a “film.” The powder coating hard finish is usually tougher than conventional paint, and for this reason, is becoming the fastest-growing finishing technology in North America, in almost 10 percent of all industrial finishing applications.
The Vitracoat High Temperature Series, suited for applications requiring heat resistance, endure over baking and tarnishing, and spray easily with good film appearance and excellent physical properties, resisting temperatures up to 800 degrees Fahrenheit. This process is used on metallic substrates such as barbecue grills, exhaust systems and fireplace parts and accessories. The cure cycles range from 15 to 35 minutes at temperatures between 400 and 480 degrees Fahrenheit, and offer great color and gloss stability. The series is available in dark colors and smooth or texture finish.
Powder coating is mainly used for covering ferrous and non-ferrous metals such as furniture, aluminum extrusions, automobile and electronic parts just to name a few although newer technologies allow powder coatings to be used on other materials with different techniques. New breakthroughs in power chemistries allow the use of the powder coatings over medium density fiberboard (MDF) and plastic made products.
Powder coatings provide a flawless finish to complex MDF shapes that traditionally are coated with vinyl, melamine, paper laminates or other organic finishing processes, such as
wavy shapes, rounded edges, concave and convex surfaces, cabinet doors and drawers with multiple sides that can be sprayed simultaneously.
Some advantages of this technique are excellent coating performance, lower operational costs, design without limitations and a one-step process. Also, the coating process is simpler because the piece hangs from an overhead conveyor, being all the sides of the piece coated at once.
“Products made in wood have now the option of powder coating with substantial advantages over other processes because it is a cost-effective, less wasteful process, it is ecologically in sync with the most aggressive international regulations to control air pollution and hazardous waste disposal, and it is more resilient for newer designs and appearances with higher quality and durability,” said Luis Moussali, vice president of operations.
The product is obtained from the blending of various components, binders, resins, pigments, fillers and additives. Through a process of extruding, grinding and pulverizing, the material looks finer than ground pepper but thicker than flour. Each particle contains the necessary components to the finishing amalgam. Once the powder is applied using an electrostatic spray process, the piece is submitted to a curing oven that melts the coating into a smooth film on its surface.
The powder may be a thermoplastic or a thermoset polymer. The thermoset powders react during the curing procedure, resulting in a molecular “cross linking” process so that after being cured, the coating will not re-melt. Examples of thermoset powders are Epoxies, Epoxy-Polyester hybrids, Polyesters and Urethanes and they make 90 percent of the powders used on metal and the wood industry. Thermoplastic powders do not “cross link” but simply melt and flow over the treated surface. If reheated, the film will melt again. Examples of thermoplastic powders are vinyl and nylon.
New technologies such as applying powder coating curable by ultra violet light allow a one-coat process and attractive finishes with good protective properties on various types of heat-sensitive substrates such as plastics, wood-based substrates and special alloys, or on pre-assembled metal products that contain heat-sensitive components.
“This revolutionary innovation allows dry-coating to be used in practically any industrial application. UV powder combines the convenience of electrostatic powder spraying with the benefits of low-temperature melting and UV curing, and can be used even in heat-sensitive parts such as pre wired electrical motors and parts that contain rubber seals such as shock absorbers,” said Moussali, “There is no toxicity, no molecular migration, and the application requires low energy and reduced plant space.” The Vitracoat technical team has developed a range of UV powders that can be melted using infrared convection techniques followed by a curing process under fast UV radiation. This process achieves powder cross linking at much lower temperatures and at faster speeds, allowing the liquid to flow into a smoother finish.
A recent investment in a state-of-the-art bonding system allows Vitracoat to offer bonding capabilities at very competitive prices, exceptional turnaround times and excellent quality control. The system is used, for instance, in metallic bonding, a technology that allows the metallic portion of the powder or pearlecent mica flakes to attach to the powder base instead of dry blending the element with a base powder. A genuine metallic effect results during the bonding process, which also reduces potential fire and explosion hazards due to aluminum based metallic particles.
The company offers a variety of product combinations for different applications, such as epoxy-polyester-hybrid, epoxies, polyester TGIC, polyester TGIC-free, polyester-urethane, polyester-acrylic in a wide range of solid, metallic, iridescent and holographic colors
The epoxy-polyester-hybrid combination offers an economical alternative to epoxies for general purpose interior coating, and can be formulated to provide superior charging capabilities, first-pass transfer efficiency and Faraday cage penetration. Some Vitracoat hybrids are FDA-approved for food-contact use, and have been recognized by Underwriters Laboratories, Caterpillar and computer companies.
Recent enhancements to Vitracoat polyester TGIC powders have provided premium durability that resist South Florida weathering exposures beyond eight years. These powders can be formulated to provide excellent chemical-solvent resistance, Faraday cage penetration, auto-gas resistance caused by substrate porosity, and scratch-mar resistance.
Polyester urethane powders, on the other hand, are designed for decorative end service applications requiring surface smoothness and/or exterior durability while polyester-acrylic powders can achieve very low glosses while maintaining outdoor performance and UV resistance.
Anti-graffiti powders are formulated to have resistance to stain and graffiti damage, and aerosol paints can be removed using xylene or trichloroethylene. These powders are excellent for exterior applications, available on a wide range of colors or as a gloss clear top-coat, used on blackboards, subway carriages and paid-phone booths.
“Vitracoat’s new plant in Elkhart will cover 14,000 square feet, with an initial installed capacity of 2.5 million pounds a year. The purpose of this factory is to service the North American market more efficiently. We already have 10 distribution centers across the U.S., but the ability of having local manufacture will allow us to respond faster to special needs and trough the new research and development center stay at the forefront of powder technology ” Moussali explained.
Vitracoat’s added value includes integral technical service in clients’ facilities to ensure that products are applied correctly and effectively. “Many times, results are not optimal because of excess use of materials, inappropriate temperatures or substrate preparation. We provide technical support and training on the “how-to” of every product we provide, helping our clients save money and optimize results,” he said.
THE MARKET, THE FUTURE
Vitracoat has experienced growth in the last years, with a steady 15 to 20 percent increase in its annual sales. However, according to the vice president of operations, the powder coatings market is a mature one, with excess installed capacity and manufacturing being sent off to Asian countries. “Despite these factors, the market continues to grow, maybe not as accelerated as it was five to 10 years ago, but it still does,” he affirmed.
Vitracoat advantages are related to its geographical proximity with the United States, the extensive experience in the industry, the state-of-the-art facilities and equipment, and now the new plant located in Indiana, easily accessible from any manufacturing company in North America. “We are also a versatile company that adapts to clients’ needs, with great response capabilities and excellent technical support. In addition, it has been our company’s policy since inception to require the highest levels of professionalism from all collaborators, suppliers and customers and to interact with high integrity standards. This code of ethics was established by my grandfather and continued by my father, Eduardo Moussali S., founder and president of the company, and has been instrumental in our business performance’s success,” he concluded.