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|COATROOM Coming off the line, these cabinet doors have just been coated with Lamineer powder-based product. ROHM AND HAAS PHOTO
|PAINTS & COATINGS
MARC REISCH, C&EN NORTHEAST NEWS BUREAU
Watching paint dry is not the most exciting of pastimes. But what if it could happen in the twinkling of an eye?
The paint industry has had the ability to supply rapid-cure coatings for some years now, but customers have been slow on the uptake. Call it a matter of comfort, or think of it as form of inertia, but industrial customers are not beating down the doors to get their hands on a technology that promises to all but eliminate air pollutants.
To be fair, large industrial concerns have huge investments in paint processes that satisfy performance criteria and meet current government air emissions standards. And providers of water-borne and high-solids solvent-borne paints have a talent for continually tweaking their products to meet increasingly stringent government regulations.
Large industrial concerns certainly would not want to take the plunge into fairly new paint systems unless they could be assured of getting cost savings and performance gains while meeting government standards. But with the latest improvements, some coatings manufacturers think they have the answer for customers who want to paint cars, trucks, lawn mowers, wood, and metal furniture.
The answer, they claim, is powder and radiation-curable coatings. Powder coatings melt and flow on an oven-baked object. They come in two versions: thermosets, which cross-link and cure as they heat up, and thermoplastics, which solidify as they cool. Radiation-curable coatings are liquids that only need a special ultraviolet light or electron-beam source to cure in an instant.
LOOKING UP The Citigroup Building in London's Docklands features Akzo Nobel's Interpon D25 architectural powder finish on the aluminum curtain wall profiles.
AKZO NOBEL PHOTO
A few years ago, some paint makers began to talk about a new hybrid: UV-curable powder coatings. The new powders combine the best of powder and radiation-cured coatings. They melt in a low-temperature oven and so can be used on some plastic and wood components. And when the powders have coalesced to form a smooth film, exposure to UV lamps instantly cures the film. Already, production lines that make use of these hybrid rapid-drying paint processes are beginning to open up.
Powder and radiation paint systems together make up only about 9% of U.S. coatings shipments, and they are coming into a slowing market. According to the Census Bureau, the value of paint shipments in 2000 was $16.2 billion, down 0.5% from a year earlier, while the volume of shipments increased marginally to nearly 1.3 billion gal. For the first six months of 2001, shipments were 666 million gal, down 2% from a year earlier. The value of those shipments slipped almost 1% to $8.6 billion.
Powder and radiation paint systems mostly serve markets catering to original equipment manufacturers. The Census Bureau statistics cover not only the original equipment manufacturer paint market, but also the architectural paint category, covering home interiors and exteriors, and special-purpose coatings such as traffic paints.
Consultant Phil Phillips values the North American paint shipments of 1.4 billion gal in 2000, including the U.S., Mexico, and Canada, at $21.2 billion. A survey of paint manufacturers by his own firm, Southern Pines, N.C.-based PGPhillips & Associates, puts paint shipments in the U.S. alone at about $17.3 billion. "The Census Bureau does not capture a lot of the growth out there," he says.
Worldwide, Phillips says, paint makers shipped 5 billion gal valued at $70.6 billion in 2000. European paint makers, both east and west, shipped 1.7 billion gal valued at $23.9 billion. Asian producers shipped 1.1 billion gal valued at $14.8 billion, and producers in the rest of the world--including South America, Africa, and the Middle East--shipped 900 million gal with a value of $10.6 billion.
U.S. per-gallon prices dropped in all categories in 2000; shipments rose only for product and special-purpose coatings
|SHIPMENTS $ BILLIONS
|SHIPMENTS $ BILLIONS
|a Applied by original equipment manufacturers. SOURCE: Census Bureau
RAW MATERIAL prices have varied this year. On the one hand, energy shortages in the U.S. early in the year helped push up prices for paint production and petrochemical-derived raw materials. On the other hand, declining industrial production meant a weaker market for the white pigment titanium dioxide, one of the most expensive paint ingredients.
According to Jim Fisher, president of Princeton Junction, N.J.-based International Business Management Associates, 2000 was a good year for TiO2, but beginning in January of 2001, industrial activity slowed. So far this year, worldwide consumption of the opacifying pigment has dropped 4 to 5%, with a similar drop in the U.S.
Fisher explains that the paper market, which normally consumes about 15% of annual TiO2 production, "has been in dire straits and I believe will remain there." Paint makers, which consume about 55% of annual production, have benefited and prices are now down to 1997 levels, he says. Even the planned shutdown of a Kerr-McGee TiO2 plant in Antwerp, Belgium, and Millennium's shutdown of a facility in Baltimore won't tighten up supplies.
The plant closings removed 68,000 metric tons of capacity from the global market, but supply and demand are still out of balance, Fisher says. And though plastics and other uses that make up the balance of demand are fairly strong, TiO2 plant utilization rates globally are still in the mid-80% range, he says.
Like the trend in raw material prices, the industrial maintenance market has been mixed. According to Jay Wilner, president of San Francisco-based consultants WEH Corp., the value of paints used to maintain bridges, industrial plants, and roads in the U.S. was about $2.2 billion in 2000 and will be flat to down in 2001.
On the plus side for paint makers, new construction at airports to put in security measures after the Sept. 11 terrorist attacks will mean increased use of paint. But airports are likely to postpone expansion plans because air travel has declined, so on balance, paint sales in this category could be flat, Wilner says.
Government spending to lift the economy should help increase paint use on highways and bridges, says Wilner. But economic and manufacturing weakness means less need for paint to maintain hotels, stores, and industrial establishments.
With difficult times like these, paint makers have been looking at ways to streamline costs. Some have done it through consolidation. Over the past two years, Valspar bought Lilly Industries, PPG Industries bought Monarch Paints, BASF bought the industrial coatings business of Rohm and Haas, and Akzo Nobel bought Dexter's aerospace coatings business. The industry counted about 1,200 paint makers about 12 years ago, and it counts about 600 now, says John F. Martin, senior manager of consultants at Arthur D. Little Inc.
Another way for an already large producer to control costs is to use a private computer network to link up with suppliers. Stephen J. Doyle, senior vice president of the Internet business group at Aspen Technology, says his company has set up an exchange it calls Aspen Buy that links paint maker ICI's North American operations with 400 suppliers.
Doyle explains that ICI can set its production schedule and order supplies timed to its needs. For instance, tank sensors at ICI's paint-making operations can trigger an automatic purchase order and eliminate the need to keep excess stock on hand. Also, as ICI's production requirements alter because of shifts in retail demand, the system can automate order changes and reduce the amount of paperwork that a change used to require.
TRADITIONAL COATINGS manufacturers are looking to supply chain and consolidation efforts to get a better handle on costs in a flat market. Makers of powder and radiation-cured coatings are trying to push advances in resins and curing systems to fuel growth.
Consultant Steven J. Nerlfi of West Caldwell, N.J.-based Kusumgar, Nerlfi & Growney says radiation can cure not only coatings but inks and adhesives as well. A new study by his firm reviews applications including compact disc coatings, flexographic inks, and prefinished wood flooring. It puts the world market for all radiation-cured products in 2000 at 430 million lb, valued at $2.3 billion. U.S. consumption was about 120 million lb, valued at $940 million.
Nerlfi sets the 2000 U.S. radiation-cured coatings market at 84 million lb, valued at $420 million and growing at 5 to 8% a year. The largest uses of these coatings are for wood furniture and prefinished wood floors. Smaller uses include coatings for optical fibers, vinyl flooring, metal, and glass.
Other consultants have slightly different estimates of the radiation-cured coatings market. Impact Marketing Consultants, the Manchester, Vt., firm that puts out the "Rauch Paint Guide," estimates the size of the U.S. market at 85 million lb, values it at $475 million, and says it is growing 9% annually.
The Rauch Guide also estimates powder coatings consumption. For 2000, the guide says consumption is 345 million lb, valued at $873 million, and forecast to grow 7% annually over the next five years.
Though the consultants' forecasts show slight differences, they do underscore growth in segments of the market that are doing better than product coatings in general, which grew less than 3% per year in the U.S. between 1996 and 2000.
As the Environmental Protection Agency and local governments continue to pressure industry to install maximum achievable controls on emissions, powder and UV-cured coatings technologies look ever more attractive. This is particularly true when manufacturers consider installation of brand new coating lines, notes Robert Nelson, the National Paint & Coatings Association's senior director of environmental affairs.
SOME PAINT MAKERS offer radiation-cured powder coatings, but the technology is in its infancy. Of the 425 million lb of powder Nerlfi estimates is used in the U.S., UV-curable powders hardly show up on the radar. Only 170,000 lb of such powders was sold in 2000, he says. While "any temperature-sensitive substrate is a potential market for UV powders," says Nerlfi, the cost of these powders is high--about $13 to $14 per lb compared with the average cost of conventional powders at $2.00 to $2.50 per lb.
PROTOTYPE After the final powder clear coat is applied during the P2Zero concept coating processes, the speed-shape powder layers are co-baked in PPG's infrared zone.
PPG INDUSTRIES PHOTO
Arthur D. Little's Martin says the major powder coatings makers include Akzo Nobel, DuPont, the Morton Powder Coatings unit of Rohm and Haas, Ferro, Jotun, and BASF. Resin suppliers include UCB, DSM, and Bayer. Suppliers of catalysts for UV powders include Ciba Specialty Chemicals and the Sartomer unit of Atofina.
Bayer, long a paint material supplier, is very interested in UV powder coatings. According to Randall S. Dearth, head of Bayer's global powder coatings business group, the company's lab technicians are looking into the development of UV-curable powders.
"Customers for UV powders tell us that growth rates are in the 10 to 20% range," says Dearth. He cautions, however, that those growth rates are likely too optimistic given the current economic downturn. But they are probably a good projection for when the world economy does pick up again.
Both the UV liquids and UV-cured powders give off minimal emissions--a reason why they are considered more environmentally friendly than solvent-borne coatings. However, UV powders have an advantage over uncured UV liquids, which must be handled with extra precaution since they can irritate skin, says Dearth. And dry UV-cured powders, he points out, are easier to handle and are also recyclable.
Bayer has been particularly interested in the powder coatings market since it acquired Sybron last year and along with it the Ruco polyester powder operations in Columbus, Ga. Now Bayer can supply not only hydroxyl and carboxyl polyester powders to formulators, but also isocyanates and pigments as well.
The purchase gives Bayer a leading position in the powder coatings market in North America, says Dearth, which the company ultimately hopes to expand globally, possibly with a joint-venture partner to produce powder resins.
Right now, though, Bayer is closely following the growth of the more traditional powder coatings market. It's a global market that Bayer places at about 1.6 billion lb. But if automakers continue their interest in powder coatings, the market is likely to grow much larger.
Chrysler has largely adopted epoxy hybrid primer-surfacer powders in its automotive factories, says Dearth. But he says Bayer's materials are likely to compete in that market, too. General Motors has begun to adopt what Bayer considers a better technology: urethane powder primer-surfacers. "At equal thicknesses, the urethane powder has better stone and chip resistance," says Dearth.
Consultant Phillips says powder coatings got their start in the early 1950s, "but they really didn't hit their stride until the late 1970s," when they began to be widely used on appliances. Though the category experienced double-digit growth until recently--Phillips puts annual growth now at just 6%--many producers did not make much profit. He values U.S. annual powder sales at about $1 billion.
"Powder producers gave a perfect example of what not to do with a new product line," Phillips says. "They didn't ask for the increase in value powder brought to the customer, because they were so anxious to sell and knock out the liquid competition." But powder coatings makers now have a chance to do things differently with the new low-temperature-cure coatings and the UV-cured powders, he says.
This is the strategy at Rohm and Haas's Morton Powder Coatings unit. "We won't play the price game, and we don't pursue unprofitable business," says Michael G. Favreau, marketing manager for the unit's Lamineer line of low-temperature-cure thermoset and UV-cured powders. Powders are based on epoxy, acrylic, and polyester, as well as hybrids of these resins, Favreau says.
The trick with low-temperature-cure powders has been not only in dropping cure temperatures to between 250 and 300 °F from about 350 to 400 °F, but also in making a stable product that will not solidify in the shipping box, he says.
Low-temperature-cure powder coatings offer furniture makers a technology that does not emit smog-producing volatile organic compounds (VOCs). The furniture industry has been struggling with alternatives to the high-VOC lacquers traditionally used to coat wood. Powder coatings offer one alternative for the medium-density fiberboard (MDF) widely used to manufacture cabinet doors, counters, and desktops.
But more important, a finisher can coat MDF in just a few steps, instead of the four to seven steps required to spray multiple liquid coats on MDF, says Favreau. Also, as an alternative to laminates on MDF, powder offers a seamless finish and won't delaminate in service from the effects of moisture and heat.
As for UV-cured powders, Favreau says not much is sold today. The company's Ultra-V powders for metal include a UV-cured line that one finisher is using on motor assemblies. However, Morton and others are still working on UV-cured powders for three-dimensional objects because of the difficulty of exposing all surfaces of a round or rectangular object to a radiation source.
UV lamp maker Fusion UV Systems is also working on extending use of UV-cured powders. The company's lamps, developed in consultation with radiation-cured coatings formulators, emit both longer UV wavelengths to cure through the film and shorter UV wavelengths to cure the film at the surface. Susan Mitchell, business development manager, says UV-cured powders could also be used to manufacture dry eraser boards, preprimed composition moldings, and mirror backings.
Also under development are clear UV-cured powders to finish temperature-sensitive substrates such as plastics and hardwoods. According to Mitchell, it is now possible to melt some UV-cured powders at temperatures as low as 175 °F because of improved resins from suppliers like UCB and DSM. She says fine furniture makers are looking into the possibility of using one pass of UV-cured powder over hardwood before sanding to a smooth finish instead of the current practice of alternately coating with lacquer and sanding three times.
Mitchell points out that UV-cured powders offer advantages to metal coaters, too. "As metal heats up, 'outgases' have to pass through the powder, producing pinholes in the paint," she says. UV-cured powders don't require as much heat, so outgassing is not a problem.
COSTS TO INSTALL a UV-cured powder line to coat MDF could run $1 million or more, Mitchell says. However, smaller powder coatings operations with only spray equipment and an oven could actually be set up in a garage at a cost of between $50,000 and $100,000, says Gary K. Sweet, president of consultant and systems supplier Powder-X Coating Systems, Huntsville, Ala. Add a conveyor, and costs rise to about $250,000, he says.
POOF Powder coatings can be electrostatically sprayed onto a product.
AKZO NOBEL PHOTO
Sweet says there are about 900 mom-and-pop custom powder coaters in the U.S. and about 200 larger operations. "We don't recommend that powder coatings operators set up a plastic or wood line now. It's just not a big business," he says. "There is enough on our plate now just to handle the metal powder coatings business."
But as furniture manufacturers and plastic coaters seek productivity and cost advantages, they may want to take a closer look at UV-cured coatings. Ciba Specialty Chemicals, a major supplier of photoinitiators used in radiation-cured liquids and UV-cured powders, says it has developed the chemistry to produce UV-cured powder coats that can be applied to doors or window frames intended for use outdoors.
Don Wostratzky, Ciba's manager of market development, says a traditional UV absorber such as a benzotriazole could interfere with the UV cure process. "But there is a way around the problem," he says. "We recommend the use of a triazine instead of a benzotriazole. Triazine does not absorb as much radiation in the 360- to 400-nm range, where most UV powders cure."
Ciba recommends a blend of two photoinitiators. Irgacure 2959, an a-hydroxy ketone, helps cross-link a powder resin at the 360- to 400-nm range at the surface of a powder film. Irgacure 819, a bis(acyl)phosphine oxide, works at the same range to cross-link the powder resin below the surface.
"This is forward-looking work," says Wostratzky. "Most application work on UV-cured powder is now for interior use. Ultimately, we expect UV powders will be used for outdoor applications."
Sharing that enthusiasm for UV-cured coatings is Ralph Lavi, powder coatings market manager at UCB Chemicals. "UV is the next step change in powder technology," he says. UCB supplies formulators with polyester powder coatings resins designed for use with various curing agents (such as epoxies and triglycidylisocyanurates).
While powder coatings formulators have been focusing on UV powder for wood, Lavi sees other possibilities. For instance, large metal items such as engine blocks would require much less energy to coat since UV-cure resins flow at a lower temperature. Ceramic tile could be made with UV powders, too, since the powders would flow at a much lower temperature than traditional glazes, Lavi says.
He also expects that UV-cured powder will compete with low-temperature cure powders for wood. UV powders would only require 40 seconds in an oven at 250 °F versus low-temperature-cure powders, which require 10 to 20 minutes at 212 to 284 °F. And he claims the UV-cure powders would be one-half to one-third thinner than low-temperature powders. So the final cost to coat an item with UV powders would be 20 to 40% less expensive.
BIG ADVANTAGES for UV-cured powders are that they are sprayable and can coat 3-D objects, says Keven Bryan, Dow Chemical's UV specialties market manager. UV-cured liquids are generally padded or rolled onto 2-D surfaces.
To expand formulators' choices in resins, Dow has just introduced a UV-curable solid epoxy, says Bryan. Most of the powder for UV-cured finishes already in the market are based on polyester and melamine-vinyl ether resins. The experimental resin with the tongue-twisting designation of XZ 92478.00 offers better chemical resistance, hardness, and adhesion than polyester-based UV-cured resins, he says. He suggests that the new Dow resin would find good use on interior furniture such as kitchen and bathroom cabinets.
Akzo Nobel's powder coatings market manager, Richard J. Higgins, thinks UV-cured powders may be developed to coat the interior of steel food and beverage cans. But while UV powder technology develops, he says, traditional polyester powder coatings have been breaking into new markets as well. For example, they are widely used to cover prefabricated metal building exteriors, especially in Europe.
The company has developed new polyester resins that, together with the right pigments, provide extra durability and UV-resistance outdoors. It sells these "ultra-durable" powders as D2000 and D525, says Higgins, and they are widely used in Europe. "The U.S. could use a lot more powder if it follows European trends and replaces paint now used on architectural metal," he says.
A trend in the past five years has been the development of powder coatings with metallic sparkle and other special effects. "We spent a lot of time and money developing these new effects," says Higgins of the special-effect powders, which are in great demand in Asia. "We do live in an age of glitter."
But one place where glitter can't yet go is in powder color coats for automotive use, according to Robert R. Matheson Jr., DuPont Performance Coating's strategic technology manager. DuPont sells powder primers and clear coats, but not powder color coats, to automakers. "Current powder technology can't match the metallic and pearlescent effects achievable with water-based color coats," he says.
Metal flake is only properly oriented in a paint film as water evaporates and the paint film shrinks, says Matheson. "We looked at magnetic fields and flow geometry to get the metal flake properly oriented in the film," he says.
However, PPG believes that stylish metallic powder color coats are possible, and it has set out to prove it in its P2Zero prototype process. In fact, Denis Taljan, decorative products director in PPG's auto coatings division, says that, because powder shrinks less than liquid-based coatings as they cure, "it is easier to manage metallic flake orientation."
And not only is the application of a stylish base color coat a possibility, it all can be done in the zero-emissions paint shops PPG hopes automakers will build once the economy picks up. The P2Zero process has no waste, gives off no emissions, uses no water, and would take up less space than liquid-based coatings lines, says Taljan.
After electrodeposition treatment of the car body for corrosion protection, a base powder coat would be applied to the car, Taljan explains. The bluish-gray layer consists of "a hodgepodge of all colors recycled from overspray of the color coat," he says. A color coat would follow the application of the base coat, and then the body would go through "a short-duration bake cycle at 300 °F to melt the powder a little." After the oven treatment, the car would get a clear top coat and then the car would go into an oven again for 20 minutes at 325 °F.
The entire paint system is based on an acid epoxy resin, says Taljan. It consists of an acid functional resin and an epoxy functional resin that cross-link as the powder melts. "This system has the same performance and same aesthetics of existing systems, but it can be done at a lower overall processing cost. It's a good business decision," says Taljan.
Aside from auto bodies, powder coatings find uses on other automotive parts. Atofina's Rilsan nylon 11-based thermoplastic powder coating is used on minivan sliding-door rails because of the good lubricity and abrasion resistance, says Fine Powders Market Manager Neil K. Lehman. It also is used to coat truck transmission components where those characteristics help increase transmission life five times beyond what it would be without the coating.
Rilsan has its major end use as a pipe coating. Atofina recently received approval from the American Water Works Association for use of Rilsan in potable-water-supply pipe. While the Rilsan powders emit no VOCs when they melt, primers to improve adhesion of the powder do. To address this issue, Atofina has just come out with Primgreen 2 primer, an emulsified diepoxide in 95% water containing 2% VOCs compared with solvent primers containing 80% VOCs.
"Any coatings technology has its drawbacks," says Arthur D. Little's Martin. For instance, the cost to convert an auto wet-spray booth to a dry-spray powder booth can be high. Consultant Nerlfi estimates those auto factory conversion costs at about $150 million.
And then there are the kinks to be worked out in advancing a new technology. Martin says the first generation of UV-cured pow-ders formed lumps as they were shipped to customers because of the initiators the powders contained to make a UV cure possible. That problem has been worked out now, and UV-cured powders have "a reasonable shelf life."
The next step for UV-cured powder resin suppliers and formulators is powders that melt between 100 and 150 °F while also remaining stable in a shipping container, says Martin. But UV-cured powders will only work in industrial settings where it is practical to apply a powder, melt it in an oven, and then expose it to a radiation source.
Like other coatings, UV-cured powders are sophisticated products. But will UV-cured powder makers and other suppliers of advanced paint systems and materials resist the opportunity to compete on price alone to knock out the competition? Maybe, consultant Phillips suggests, the leaders will do things differently this time.
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