During the last 10 years, the foremost driver of technological change in paints and coatings has been reducing traditional solvent use. Regulations designed to reduce air pollution have forced paint makers and their raw materials suppliers to develop high-solids, waterborne, powder and other technologies that have revolutionized the industry. Most of the regulations exist to reduce the use of the volatile organic compounds (VOCs) that produce ozone.
As of Jan. 1, more California-like AIM regulations are being implemented in New York, New Jersey, Pennsylvania, Delaware, Maryland, Washington, D.C., and Northern Virginia, which call for VOC content as low as 100 g/L for flat paints and 250 g/L for high-gloss paints, 340 g/L for industrial maintenance coatings, and 250 g/L for primers and undercoaters.
How have these mandates affected raw materials suppliers? Romesh Kumar, technical manager of coatings at Clariant, says, "The VOC limits vary from state to state, and are mainly controlled by the paint manufacturer. There is a trend toward low VOC paint. Clariant is offering a line of pigment preparations, Colanyl 500 and Sandosperse E, which are suitable for low VOC paint."
Kumar says that an optimized low VOC system does not show lower performance. "This requires proper selection of surfactants and pigments. Our regular Colanyl 100 type and Colanyl 500 low VOC type colorants offer the same performance. Sandosperse E preparations are designed for high durability, no-VOC industrial coatings," he says.
William R. Sparks, business manager of architectural coatings at BASF Functional Polymers Group in North America, says, "The low VOC architectural market is still a niche market, but one that is growing at an above average rate because regional regulatory bodies have introduced mandates." Sparks says that because national companies producing paints and coatings want to sell their formulations nationwide, they will respond with low VOC products that meet requirements across regions. Sparks adds, "We expect that regional manufacturers will follow the national companies."
When it comes to liquid architectural coatings, Clariant's Kumar says there is a trend toward improved performance, both for the integrity of the paints and resistance to color change. He says, "Other trends include higher opacity for coverage in one coat, ease of cleaning, and bold colors - especially in bright red and violet shades. Clariant offers Permanent Orange 2RLD-70, Hostaperm Red D3G-70, Hostaperm Pink E, and Hostaperm Red E3B as high durability pigments for liquid paints for this market. The current state and federal regulations do not allow lead-based pigments or HAP-positive chemicals, and are not used in architectural coatings sold in the United States."
When asked specifically where liquids fit into the architectural market, Kumar says that liquid paints (80 percent aqueous and 20 percent solvent-base) will remain the major part of both interior and exterior architectural coatings, because of ease of application and relatively lower cost.
Eastman Chemical Co. offers some new coalescents for the U.S. architectural coatings market, too, which were on display at the International Coatings Expo in Chicago, in October last year. The portfolio includes Texanol ester alcohol, Eastman EEH solvent and Optifilm Enhancer 400. According to Eastman, these coalescents, used individually or in combination, help formulators optimize performance in their architectural coatings, while meeting VOC regulations.
"Eastman is committed to providing formulators with more options to develop coatings that balance performance and regulatory compliance issues," says Charlie Giaudrone, global industry leader, Building and Construction at Eastman. "With new options for lower VOC and odor added to Eastman's... products, this portfolio of coalescents delivers superior film integrity and durability in a wide array of interior and exterior architectural coatings, including flat, non-flat and specialty applications," he says.
More Finishing OptionsAn alternative coating for the architectural market is powder. In Europe, powder coating is predominant in the architectural market. In North America, powder coating only makes up 6 percent of coatings applied in the architectural market, while in Europe, that percentage jumps to 50 percent, according to Dr. R. Higgins, Akzo Nobel Powder Coatings (Figure 3). So, where exactly does powder coating fit in this market?
"Aluminum extrusions are a major potential market for powder coatings in North America," says Jeff Palmer, communications director at Powder Coating Institute (PCI), Alexandria, Va. "In monumental and light commercial buildings, facades, curtain walls, panels and louvers can be powder coated, along with other building components. Powder is used on storm doors and window frames, but there is room for growth in these areas, along with fencing, door handles, locks, lighting fixtures and balustrades," he says.
Why has powder not caught on in North America? According to Palmer, "The Powder Coating Institute and its members have become increasingly more involved in the past few years in analyzing the North American architectural market and the potential for greater penetration by powder coatings in this market."
He says the association has held several meetings with architectural industry leaders over the past two years to learn more about their industry, and conducted market research during the summer of 2004 with architects, contractors, designers, specifiers, aluminum extruders and powder coaters. This has helped PCI learn about their knowledge and perceptions of powder coating and what would be involved to increase the use of powder coating in the architectural market.
"The greatest challenge PCI sees as a trade association," Palmer says, "is in educating the architectural industry decision makers on the various uses and benefits of powder coating - its durability and versatility in the market. While coating end users have some knowledge of powder coating, the architects, designers, contractors and specifiers who influence the type of coating that is used in a building project have limited knowledge of powder coating, and so they go with what they know, i.e., other finishing methods."
He says that some of them have misperceptions about powder coating and believe it is limited in color and textures, is not durable or long-lasting, is more expensive than other finishing methods, and is a lengthy and complicated application process. "PCI is working to address these misperceptions," he adds.
How will the association address them? Palmer says that PCI can educate specifiers and influencers about powder coating by compiling test data and specifications from its members to make available online as well as by hosting seminars that offer CEU credits to architects and specifiers. They also can participate in relevant trade shows and powder coating presentations to architectural schools to reach the next generation of architects. The association also will produce literature that addresses the benefits of powder coating with test data they seek. Palmer adds, "PCI has formed an Architectural Working Group to develop a multi-year marketing program to reach the North American architectural market, which could echo the success powder coating has shown in the European architectural market."
John J. Binder, marketing manager, Coating and Finishing Systems Group at Nordson Corp., has been studying the architectural market since December 2002 "in anticipation that the current vertical liquid aluminum extrusion coating market would be converting to powder." He says that presently there are quite a number of vertical aluminum extrusion coaters looking at powder due to the recent EPA regulations to reduce VOCs and install thermal oxidizers.
"Nordson already has many customers that are powder coating aluminum extrusions horizontally. The advantage of coating tall extrusions vertically is primarily 40 percent more throughput than a horizontal line. Many liquid coaters already know this and are currently coating vertically," he says.
"Therefore we see the vertical liquid-to-powder conversion market as having great potential in the United States right now," Binder says. "Asia has been primarily anodizing and Europe primarily powder. The United States is [just about] all liquid for the vertical market. We feel the key to this new market is line speed." He says that current liquid vertical customers are coating anywhere from 15 to 25 fpm. European competitors with vertical powder system experience are recommending line speeds in the 4 to 5 fpm range to the prospects. "This is far too slow for U.S. vertical customers. Nordson is taking an aggressive approach at pursuing this market with strong developmental and application engineering focus on system and equipment design specifically for this market with superior powder application and color change capability that is already proven in the horizontal vertical extrusion market as well as other markets." Binder adds that Nordson also has strong partners in the Midwest (with Belco), and on the West Coast (with Tellkamp), with years of experience in the vertical liquid market.
Pierre Bols of Trevisan Cometal North America Inc., a subsidiary of the Italian-based group Trevisan, located in Dallas, confirms that, saying, "[Trevisan] just secured an order for a complete line at Extruders, Division of Atrium, in Wyllie, Texas, that will start operation by the middle of 2005."
Since 1980, Trevisan has installed more than 120 vertical powder coating lines worldwide and is market leader in this field, according to Bols.
He says the main part of aluminum extrusion for architectural use is done on vertical painting lines. He adds that the United States is one of the markets in the world starting to change from liquid to powder for architecture. "Most architectural powder coating of the still small but increasing volumes in the United States is done on horizontal lines. Using vertical powder coating lines will be much more cost efficient and competitive. To support this change is our challenge for the next decade," Bols says.
One of the disadvantages in powder is the time it takes change color. Companies are addressing that, though, and color changes in a gap of three feet are now possible on many conveyor lines.
When asked about the advantages of powder for the architectural market, Clariant's Kumar says that powder coatings offer high durability and a variety of finishes and colors. "Applied as a single coat at 2 to 3 mil film thickness, powder coatings offer excellent hiding to cover the imperfections in the substrate," Kumar says. Superior functional properties such as scratch and mar resistance, easy cleaning and high resistance against chemicals are other advantages. "The pretreatment of metal surface is simple, no undercoat or primer are necessary. A variety of polymers can be used to fit the necessary properties and substrates for desired effects," he adds.
And unlike alternate systems such as coil and vinyl coatings, powder coatings also offer a variety of bold and bright colors that are not possible with other single coat systems. "With the introduction of newer superior performance resins and high performance pigments, powder coatings will find more usage in architectural systems," he says.
"Clariant is offering a variety of pigments for coloration of such powder coatings. These include Hostaperm Yellow H3G, Hostaperm Yellow H5G, Hostaperm Oxide Yellow BV, Hostaperm Scarlet GO, Hostaperm Red E3B, Hostaperm Pink E, Hostaperm Red Violet 3RL, Hostaperm Red D2G-70, Novoperm Orange HL-70, Hostaperm Blue A4R, Hostaperm Blue BG, and Hostaperm Green GNX." When asked what the disadvantages of powder could be, Kumar says, "Disadvantages include a relatively lower gloss, relatively higher curing temperature, and usually smaller metal parts that can be colored."
ITW Gema's Fooksman says, "The rest of the world embraced powder coating for aluminum extrusions for environmental and durability reasons. Powder eliminates the VOC issue and hazardous waste disposal. The durability of the coating reduces rejects during the fabrication and installation of the final product. Users around the world have benefited from powder coating for over 20 years especially in Europe. As architects become familiar with the benefits of powder coating, [ITW Gema feels that] powder will grow in North America. We also believe having an installation in the United States will open the door for further investment in this market in the future."
Liquid and powder coatings for the architectural market both have a lot to offer. Selection depends on the specific appearance and performance properties that are needed for the project. The UV resistance of PVDF is superior to most organic powder coatings but powder may provide improved mechanical properties at a lower cost with substantially reduced VOCs. Weathering, scratch resistance, color, texture and chemical resistance are important factors that influence the correct coating choice.