Chemical & Engineering News,
August 25, 1995

Copyright © 1995 by the American Chemical Society.

Marc S. Reisch

C&EN Washington

Paint shipments rose 7% in 1994, mirroring generally strong overall economic growth.

Manufacturers of aerospace paints anticipate little problem in meeting regulatory goals.

Regulators plan to curtail use of methylene chloride, the grande dame of paint strippers, because of toxicity.

Some industry sectors resist EPA's regulation of emissions from paints and coatings.

U.S. shipments of paints and coatings reached a record in 1994, rising 7% from 1993 to more than 1.2 billion gal, as sales increased more than 5% to over $14 billion, according to the Department of Commerce.

Just as paint industry growth paralleled strong U.S. economic growth in 1994, paint sales have slowed along with the economy in the first half of 1995. Both sales and shipments rose less than 3% in the first half of 1995 compared with last year's first half. Still, paint sales and shipments are on the rise, and they likely will set new records again in 1995. However, the growth of this large and complex business gives little hint of the turbulence beneath the surface.

Ever since the Clean Air Act of 1990 became law, paint makers have been faced with the task of sharply modifying liquid paint formulas that have worked well for years. The legislation effectively forces paint makers to reduce the use of solvents that emit volatile organic compounds (VOCs), which are precursors of lower atmospheric smog. The act seeks to limit use of certain chlorinated solvents that can destroy upper atmospheric ozone. And it also imposes limits on the use of paint formulating materials that are considered hazardous air pollutants (HAPs) because of the human health hazards they pose. Deadlines when new environmental regulations go into effect in 1997 and 1998 are fast approaching for architectural, industrial maintenance, automotive, wood furniture, and aerospace coatings.

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Ciba researcher isolates a new pigment.

With rare exceptions, liquid coatings contain VOCs, HAPs, or chlorinated solvents. Such coatings now make up more than 95% of total coatings used. However, low- or no-VOC alternatives to liquid coatings are widely available.

Industrial paint consumers can switch to the use of oven-curable polymeric powder coatings. The powders emit little if any VOCs or HAPs, but they require large investments in ovens and powder-spray equipment. Thermal-spray coatings are another alternative. Specially designed spray guns heat and propel polymeric or metallic powders at industrial parts to form high-cost, highly durable coatings. Coatings that cure upon exposure to ultraviolet light or electron-beam radiation can replace traditional liquid coatings, but they also can require substantial capital investments in new equipment.

Paint users - industrial as well as house painters - still largely prefer liquid coatings, whether the coatings are brushed, sprayed, or rolled onto a surface. The preference derives in part on the long familiarity most users have with liquid coatings, the large investment many users have made in equipment that handles liquid coatings, and users' reluctance to dispense with tried-and-true liquid-coating techniques. In some cases, alternatives to liquid coatings are not practical. House painting without liquid coatings just does not seem possible. Then, too, some objects are just too large to paint without the use of liquid paints that cure at ambient temperatures. Bridges and jumbo jets, for instance, cannot practically go into ovens or have too many curved or angled surfaces to permit exposure to a radiation source for even curing.

Liquid coatings, then, will be around for a long time. However, convincing liquid-coating manufacturers to reformulate liquid coatings to comply with environmental regulations has not been easy. Architectural and industrial maintenance paint formulators and material suppliers have allied against EPA's VOC reduction models. The two sides are still battling over how far the regulations ought to go, as well as when and how they ought to go into effect. The outcome of this standoff will affect roughly 65% of all coatings produced annually in the U.S.

Some industry sources suggest that a political climate favorable to industry may dull the impact of EPA proposals to limit emissions of VOCs and HAPs from paint. Republican leaders in both houses of Congress have been looking closely at EPA's budget with an eye to reducing national expenditures. Cuts in EPA funding could hurt EPA's regulatory efforts.

But while most paint producers would like to see Congress take "some of the sting out of EPA," as one consultant put it, they do not necessarily want EPA to drop its efforts to provide broad national VOC and HAP reduction targets for the industry. "The worst thing that could happen would be for EPA not to issue countrywide regulations," says the consultant. Then, most national paint makers would have "a mess dealing with regulations on an individual state by-state basis."

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Ciba process engineer monitors pilot-scale pigment synthesis.

Paint industry officials in Washington, D.C., now report EPA officials may be a bit more flexible in the agency's attempt to regulate the architectural and industrial maintenance paint category. Arguments between EPA and paint makers are not inevitable though. Paint formulators, material suppliers, users, and EPA have agreed to reductions in VOCs and HAPs for some much smaller paint markets such as wood furniture coatings and aerospace coatings.

However, the effort to reformulate coatings is costly, and it especially hurts smaller paint makers in this competitive industry where profit margins are generally slim. But it can provide business opportunities for the swift-footed purveyors of new materials. Formulators also may have an opportunity to gain market share as they incorporate new paint materials into their coatings lines.

Surviving aerospace coatings manufacturers, like producers of other paints, have had to adapt quickly to compete in their market. Some producers have bought competitors to get an edge in the market. Today, three major paint makers make more than 90% of the coatings used to paint aircraft. They are Courtaulds Aerospace, Glendale, Calif.; Dexter Aerospace Materials, Pittsburg, Calif.; and Deft Finishes, Irvine, Calif. Two of these companies, Courtaulds and Dexter, have grown recently via acquisitions.

Although it is a relatively tiny, $65 million-a-year business, the aerospace coating business is, in some ways, a microcosm of the much larger paint industry. Its formulators must bring out coatings that comply with new regulations even as they attempt to guard and expand their share of the market.

Owners of aircraft, like those of homes and industrial facilities, also have to consider how they remove paint and prepare a surface for fresh paint. Whether for decorative or maintenance purposes, painters sometimes must start a new paint job by removing layers of old paint. Because regulators are concerned about user exposure to methylene chloride, the traditional paint remover, material suppliers have come to the rescue with a number of new materials that comply with regulations.

Material suppliers have also come to the aid of 800 or so paint formulators that are struggling today to meet new government regulations. These suppliers now offer resins, solvents, pigments, and fillers that promise to reduce VOC and HAP content in coatings.

Robust economy = upbeat market

The paint industry had an especially good year in 1994, according to the Department of Commerce. It is an industry that, even in good years, usually reports growth in annual shipments in the low single-digit rates. But a strong economy in 1994 helped push industry shipments up nearly 7% to 1.2 billion gal following a similarly large increase in 1993.

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Earlier years were not so strong. The effects of recession showed in 1992, when shipments rose just about 2% after a drop of nearly 5% in 1991. Compound annual average growth of paint shipments between 1990 and 1994 was just 3%.

Shipments of architectural coatings, the largest segment of the paint market, grew more than 6% in 1994 to 645 million gal. Improvements in new housing construction accounted for the increase in shipments. Better economic times also meant people had more money to maintain and redecorate their homes and businesses.

Product coating shipments rose 7% in 1994 to nearly 382 million gal. Demand soared last year for automobiles, appliances, metal furniture, and other products that original equipment manufacturers paint. But as good as 1994 was for suppliers of paint to original equipment manufacturers, 1993 had been even better. Revised Commerce Department data show that shipments climbed more than 14% in 1993 to 357 million gal as automotive paint use, which accounts for a substantial portion of the category, soared along with automotive production.

Special-purpose-coating shipments were especially strong in 1994. Shipments of these coatings, which include bridge maintenance and highway traffic paints, rose more than 8% to 194 million gal. The increase in shipments suggests that improvements in the economy have made more revenue available for local, state, and federal infrastructure maintenance after recent years of relative neglect.

In dollar terms, the value of paint makers' shipments increased nearly 6% in 1994 to just about $14.1 billion. Revised Commerce Department data show that the value of 1993 shipments rose more than 7% from 1992 to $13.3 billion.

Within specific product categories, the value of architectural coating shipments rose more than 5% in 1994 to $5.9 billion, and product coating shipments increased more than 6% to $5.1 billion. The value of special-purpose coatings rose 4% to almost $3.1 billion.

In 1994, architectural coatings accounted for 53% of all paint shipments, but only 42% of the value of total shipments. Product coatings accounted for 31% of shipments, but 36% of the value of those shipments; special-purpose coatings were 16% of all shipments, but 22% of the value of those shipments. These percentages vary only marginally from year to year.

The average cost per gallon of paint on the producer level was $11.52 in 1994, down a little more than 1% compared with the 1993 figure. Within individual market categories, average price per gallon for architectural paints and product coatings dropped 1% to $9.16 and $13.30, respectively. Special-purpose coatings declined more steeply - down nearly 4% to $15.82.

The price a consumer pays for a gallon of paint is not necessarily the same as the producer price. Industry consultants note that a producer may sell a gallon of architectural paint for an average price of $9.16, but the cost to produce the paint averages around $6.00 per gal. The paint formulator therefore marks up the cost of the paint by about 50%. Retailers mark up the paint they sell to the consumer another 45%, so the customer pays an average of about $13.30 a gal. The number and size of markups may vary by category. Large original equipment manufacturers often buy their paints from the producer, so they will pay the producer price for a gallon of paint.

The Department of Labor's paint price index and paint material price index have increased less than the rate of inflation of between 3 and 4% for the past few years. The government's index of paint material costs declined more than 3% between 1991 and 1993. Over the same period of time, average producer prices per gallon of paint increased less than 3%.

The Labor Department reports raw material prices increased a modest 0.5% from 1993 to 1994. However, the agency shows a nearly 2% increase in prepared paint prices from 1993 to 1994 even though the Commerce Department shows an average decline in prices of more than 1%. A spokesman for the Labor Department suggests the discrepancy occurs because of slight differences in reporting techniques used by the two agencies to compile their data. For instance, the Labor Department's indexes take into account discounts and rebates to customers, but the Commerce Department calculates its data on the face value of shipments to customers.

Discounts and rebates to customers may have become a more widespread phenomenon in recent years than they were in the past. Large national home centers and building-supply outlets buy huge quantities of paints for retail distribution. Their buying power allows them to extract discounts from paint makers that smaller accounts cannot obtain. According to paint industry consultants Business Trend Analysts, Commack, N.Y., home centers and other building-supply outlets now distribute one-third of paints sold at retail. At the same time, distribution through department stores, hardware stores, and traditional wholesalers has steadily decreased.

Although the growth of building-supply centers may have had an impact on prices in 1994, recent raw material price increases suggest prices for prepared paint are on the rise in 1995. Between January and July of this year, the Labor Department's paint material price index and the prepared paint index both rose more than 3%.

Recent paint price increases reflect, in part, escalating prices for paint resin and titanium dioxide. Titanium dioxide prices "remain fairly high because of tight capacity," says Dennis H. Reilley, vice president and general manager of DuPont's white pigment and mineral products business. Industry capacity utilization rates top 90%, and producers using the chloride production process for the white opacifying pigment incorporated in most paints are now running at 95 to 97% of capacity, says Reilley. Prices promise to remain high, he adds. Civil unrest has restricted production of high-grade titanium ore in Sierra Leone mines, notes Reilley, tightening world supplies of the titanium dioxide feedstock.

Data available so far this year indicate a slight rise in paint industry employment. However, the Labor Department reports that, through 1994, the paint industry reduced the number of its employees to control costs. The industry employed 57,800 people in 1994. But it managed to ship 10% more paint between 1990 and 1994 with 5% (3,300) fewer employees. Paint makers continued their cost-containment efforts from 1993 to 1994, when total industry employment declined nearly 1%. The industry employed fewer production workers in 1994 - 27,500 compared with 27,900 in 1993. And it employed fewer nonproduction workers in 1994 - 30,300 compared with 30,400 in 1993.

The number of paint and coating producers also contracted last year. Industry sources place the number of U.S. coating formulators between 800 and 900 companies. Ten years ago, about 1,200 formulators were producing paint in the U.S. Large producers continue to gain in size and market share as they merge with or acquire others.

One of the more dramatic paint industry combinations took place earlier this year when ICI and its U.S. paint company, Cleveland-based Glidden, purchased the Grow Group, headquartered in New York City. However, Sherwin-Williams, also based in Cleveland, made a hostile bid for Grow Group shortly after ICI made its initial $290 million bid. Ultimately, ICI purchased Grow Group for $350 million, adding $500 million in sales to its more than $1 billion in North American paint sales. ICI followed its successful June acquisition of Grow Group with the July acquisition of South San Francisco, Calif.-based Fuller-O'Brien Paints. ICI declines to say how much it paid for Fuller O'Brien, which had $80 million in 1994 sales.

At least two other small transactions took place this year. In February, Sherwin-Williams acquired FLR Paints, in Bradenton, Fla., a regional producer of specialty stains, sealers, and coatings in the southeast U.S. In July, Dresser Industries' Houston-based Bredero Price acquired Pipe Line Coatings, also of Houston. The latter company manufactures pipe-insulating coatings in Channelview, Texas.

These recent transactions, as well as other mergers and acquisitions in recent years, continue to show that smaller businesses are vulnerable in a business climate favoring larger and better financed businesses such as ICI and Sherwin-Williams. Larger companies, for instance, can better afford the cost to research, reformulate, and test liquid coatings that contain fewer volatile organic compounds and hazardous air pollutants. So it seems inevitable that the number of paint formulators will shrink in the years ahead as strong national producers gain market share.

Three main paint categories break down this way:

Architectural coatings Product coatings Special-purpose coatings

Regulatory goals within reach

In some respects, the aerospace coating industry is a microcosm of the larger paint and coating industry. Some manufacturers of coatings for large commercial jets, military aircraft, and small corporate aircraft have merged or acquired other producers to increase their market share. Manufacturers of these coatings have also faced government pressure to reformulate coatings to contain fewer volatile organic compounds (VOCs) and hazardous air pollutants (HAPs).

But aerospace paint manufacturers differ markedly from manufacturers of architectural and industrial maintenance paint in at least one significant way. The aerospace paint makers, users of their coatings, and EPA have recently agreed to industrywide standards for the VOCs and HAPs in a gallon of paint. Architectural and industrial maintenance coatings manufacturers are still wrangling with EPA over VOC regulations governing more than 50 categories of coatings.

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Technician spray paints a commercial aircraft cabin.

Aerospace coating producers now plan to meet a standard, which will go into force in 1998, that requires primers to contain no more than 2.9 lb per gal of both VOCs and HAPs, and top coats to contain no more than 3.5 lb per gal of both VOCs and HAPs, according to paint industry consultant Steven J. Nerlfi, director of Kusumgar & Nerlfi, North Caldwell, N.J. Back in 1980, says an industry source, aerospace paints could contain VOCs as high as 6.6 lb per gal.

"It is easier to get a smaller group of coating suppliers to agree on standards," says Nerlfi, than it is to get a much larger group - such as the architectural and industrial maintenance paint makers - to agree on them.

The larger group, composed of hundreds of paint makers from small, regional producers to formulators with operations nationwide, "have lots of splinter groups and factions," notes Nerlfi. By contrast, three paint makers dominate the aerospace paint market - accounting for 90% - and an additional five or six firms participate in the market to some degree, he says.

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Workers paint the exterior of a jumbo jet.

The big aerospace paint makers are Courtaulds Aerospace, a unit of U.K. chemical firm Courtaulds; Dexter Aerospace Materials Division; and Deft Chemical Coatings. Courtaulds, which enlarged its share of the U.S. aerospace paint market with its purchase of DeSoto's aerospace coating business about five years ago, claims to be the largest aerospace coating supplier in both the U.S. and the world. Other, much smaller producers include Pratt & Lambert (Buffalo), PPG Industries, and DuPont.

Michael Growney, senior consultant with Kline & Co., Fairfield, N.J., estimates the size of the aerospace coating market at about 2.3 million gal, which had a value of $65 million in 1994. Thus, aerospace coatings represent less than 1% of the value of coatings shipped in 1994 and less than 1% of the volume shipped. But they are high-value coatings sold at an average price of $28.26 per gal compared with the $11.52 per gal for all coatings shipped in 1994.

Maintenance paints for the large U.S. fleet of both military and commercial aircraft consumed 53% of aerospace paints sold in 1994, says Growney. New military aircraft consumed about 20%, new large commercial aircraft accounted for 19%, and new small aircraft used about 8% of aerospace paints sold. Nerlfi points out that U.S. budget cutbacks have slowed military aircraft production from previous years. And excess inventories of large commercial jets have slowed production at big aerospace manufacturers such as Boeing. As a result, both original equipment markets consume much less paint than in previous years.

Long term, says Nerlfi, small-aircraft production probably will grow because of recent congressional action reducing producers' liability for aircraft flight failures. A new federal law reduces product liability for manufacturers such as Piper, Cessna, and Raytheon to 18 years from the lifetime guarantee they had to offer previously. Before passage of the new law, small-plane liability insurance cost more than $100,000 over a plane's lifetime, and the market for small propeller-driven aircraft disappeared. Nerlfi thinks the new rules will help the market recover in the next few years as small-plane makers gear up production.

According to Alan Schoeder, aerospace coating market manager at Courtauld's, much of the aerospace paint industry has been moving to lower VOC emissions since at least 1988, prompted in part by California local government authority regulations. The 3.5-lb-per- gal top-coat VOC limit and the 2.9-lb-per-gal primer VOC limit will not be difficult for the industry to meet, he says. In some specialty applications, such as electroconductive coatings for housings for radar antennae, industry and government agreed to higher VOC limitations.

To meet VOC restrictions, Schoeder says Courtaulds has a new high-solids, two-part polyurethane coating for military aircraft. The company's high-solids Desothane HS solves the viscosity and flow problems associated with other high-solids, low-solvent-content paints. In addition, says Schoeder, Desothane HS has better exterior durability than other high-solids formulations now on the market.

Schoeder admits that the cost to reformulate epoxy primers and polyurethane top coats for aerospace use has been high. But the research effort ultimately pays off. "It helps our market share because we are willing to spend the money," he says.

One sticky problem for Courtaulds and the rest of the aerospace industry is how to remove chromates - the best agents available to inhibit corrosion on aluminum - from epoxy primers. Heavy-metal chromate pigments are considered human health hazards. Schoeder argues that the industry really does need chromate-pigmented primers. "Replacements have only 80% of the corrosion resistance of the chromates," he says. And if the primer fails to prevent corrosion, the result could be "catastrophic failure. Planes crash. People die."

John Martin, a senior consultant for Cambridge, Mass.-based Arthur D. Little, agrees: "Replacements are just still not as good" as the chromates for corrosion protection.

Schoeder says the industry has successfully removed chromium-, cadmium-, lead-, and zinc-based pigments from the polyurethane top coats, where corrosion resistance is not the biggest concern. Most paint producers now successfully use organic pigments in their place, he says.

Tracy Garrett Jr., national sales manager for privately held Deft Chemical Coatings, says Deft sells about $20 million in aerospace coatings annually. Chromate-free primers are a major concern for the company, which is a big supplier to the Army and Navy. Deft sells a two-part, water-reducible, chromate-free epoxy primer that meets military specifications. The proprietary, patented coating "performs very well. Don't sell it short," he says. It meets military specifications and is available for commercial use. But he does add, "You cannot ever say a chromate-free primer performs as well as chromate primers."

Although the industry may be having difficulties eliminating chromates, it has had more success in lowering the VOC content of coatings. Current technology has allowed Deft to lower VOCs in its chromate primer systems to between 2.0 and 2.8 lb per gal, a range that satisfies the industry standard of 2.9 lb VOC per gal. Longer term, Deft expects to have a water- reducible, no-VOC epoxy primer system on the market, says Garrett.

One advance Deft has worked on for military aircraft is a primerless top coat. The polyurethane top coat has a VOC content of 3.5 lb per gal. Because the two-coat system need not be applied as thickly as a primer plus top-coat system, a large military plane painted with the primerless top coat could be lighter and would thus be able to carry a heavier payload. The primerless system also would save application labor, and the reduced dry-film thickness would make it easier to strip and repaint an aircraft.

Dexter, another large manufacturer of aerospace paints, also reached its present size via acquisitions and alliances. Dexter acquired Crown Metro a few years ago, and it more recently purchased Akzo-Nobel's U.S. aerospace coating business and formed an alliance with Akzo in Europe to sell coatings outside the Americas.

According to Jeff McClelland, president of Dexter Aerospace Materials Division, the aerospace coating market has become particularly competitive as customers demand "longer life performance, low-solvent-content formulations, and heavy-metal-free pigment systems." The company's research staff has been able to meet customers' requirements for water-based products and high-solids, low-VOC paints.

Charles R. Hegedus, lead applications chemist for Air Products & Chemicals, notes that the Naval Air Warfare Center in Warminster, Pa., has worked for about eight years to reduce VOC emissions from military aircraft paint systems as well as to eliminate the use of chromate pigments. He spent 17 years with the Navy researching aircraft coating technology before joining Air Products two years ago.

Hegedus says the Navy now specifies a variety of new materials, including waterborne polyurethanes, waterborne epoxies, reactive diluents, and corrosion-inhibiting mixed-metal pigments to aid its efforts to eliminate both VOCs and heavy-metal pigments in the paint it buys. But Hegedus admits that even though the Navy's low-VOC, waterborne, and non-chromate-pigment systems perform under severe military service, "the Navy repaints more often than the Air Force or commercial plane owners because it operates under the most extreme environmental conditions. Its aircraft are subject to attack from seawater, stack gases, engine exhausts, and a lot of dirt."

Hegedus notes that the Navy's paint research efforts prove "empirically" that more advanced paint systems work. Among the corrosion inhibitors that the Navy has found will substitute for chromate pigments are molybdate, nitrites, borates, silicates, phosphates, and metal cation systems. But, says Hegedus, "It takes a lot of chemistry to develop a suitable replacement" for chromates.

Paint material suppliers are working with the Navy as well as with industry paint manufacturers to reformulate aerospace coatings. David McClurg, a development chemist for Bayer, says the company has worked both with military and commercial customers to supply polyester polyols and aliphatic isocyanates for low-VOC top coats. McClurg says two-part aliphatic polyester polyurethane top coats are widely used because of their excellent exterior durability, resistance to breakdown from ultraviolet light exposure, flexibility, and resistance to chemical attack from airplane hydraulic fluid.

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James Delaney, coatings technical services manager for the U.S. arm of Switzerland-based Ciba-Geigy, says aerospace paint formulators are using Ciba's red-orange higher performance diketo pyrrolo pyrolle (DPP) organic pigments in aerospace top coats. Like the heavy-metal pigments they replace, the DPP pigments have good exterior durability and weather resistance. Other pigments Ciba provides include quinacridone reds and mixed-metal oxide yellow.

Ciba's coating systems market manager, Enrique Irizarry, says Ciba is developing high-solids and waterborne epoxy resins for aerospace use. But he voices some caution even as many in the industry herald new coating developments. "The polymers in use have good track records. We should hesitate to make sweeping changes," he warns. "Insurance costs, product liability, and public safety must be considered" as the industry attempts to further modify its corrosion protection paint systems.

Dow Chemical's J. Jeff Johnston, industrial protective and civil engineering coating market manager, says: "Waterborne epoxy systems do not have the same cost-performance ratios as conventional solvent systems yet." Instead, he recommends newer low-viscosity bisphenol-formaldehyde epoxy resins to formulators, who can use them to blend high-solids, low-solvent coatings.

To hurry along the day when aqueous epoxy systems perform as well as solvent systems, Robert W. Thomas, epoxy additives market manager for Air Products, says the company is improving the performance of its amine-adduct-based curing agents. The company's new Anquamine 419 for use in a water-reducible epoxy-resin system helps such a system deliver corrosion protection almost as well as a high-solids epoxy-solvent system, he says. The company also has a line of modified polyamidoamines for use in high-solids epoxy systems. Last year, Air Products introduced its fast-drying, reduced-viscosity Ancamide 2353 polyamidoamine, which "some aerospace paint manufacturers are evaluating now because of its excellent corrosion protection," says Thomas.

Air Products' North American market manager for special additives, David Warnke, says new surfactants for waterborne coatings contribute almost no VOCs to formulations for aerospace and other uses. The firm recently added a new surfactant, Dynol 604, which Warnke claims "has the lowest surface tension of any organic surfactant."

Air Products' Hegedus points out that the "Navy has already proved it is possible to reduce environmental pollutants in aerospace paints." Material suppliers say they are ready to help the commercial aerospace business go just as far as the Navy.

Methylene chloride hard to beat

Methylene chloride has been the paint stripper of choice for years. Some industry experts believe it still has a future. However, government regulations will force a reduction in use of this near-universal paint stripper because of concern over its toxicity to humans.

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Worker uses Turco chemical paint stripper on an aircraft.

Methylene chloride is an almost perfect paint stripper. It works well on wood and metal, and it works fast. Maintenance managers responsible for industrial complexes use the stripper, as do aircraft painters, furniture makers, and homeowners. About 40% of the 360 million lb of methylene chloride sold in the U.S. in 1994 went to paint stripping - the chemical's largest single use - followed by metal cleaning, plastics, and pharmaceutical manufacture.

At first blush, methylene chloride appears to be a benign product. Although it has a low boiling point (103°F), it does not persist in the atmosphere. As a result, the Environmental Protection Agency and most state regulatory agencies do not classify it as a contributor to the formation of ozone - a major component of smog - in the lower atmosphere. And although it is a chlorinated solvent, it is not a factor in stratospheric ozone depletion.

But methylene chloride does have three bad raps: The chemical is listed as a toxic air contaminant under the Clean Air Act of 1990. It is one of the substances that must be reported under the Toxics Release Inventory of the 1990 Superfund Amendment & Reauthorization Act. And, in some quarters, methylene chloride is considered a suspected carcinogen. For these reasons, the Occupational Safety & Health Administration (OSHA) is lowering its permissible human exposure limit to the paint stripper from an eight-hour time-weighted average of 500 ppm to 25 ppm.

However, Stephen Risotto, executive director of the Washington, D.C.-based Center for Emissions Control (CEC), says reports of methylene chloride's demise are premature. CEC examines ways to control emissions of halogenated solvents and receives its funding from halogenated solvent producers. Risotto says a new study financed by Dow, Vulcan Chemical, ICI, and other global producers suggests methylene chloride may not be a cancer hazard at all.

Based on the study conducted in ICI's labs, the industry is petitioning OSHA to reexamine its decision to limit human exposure to methylene chloride to the 25-ppm standard. Producers now recommend an eight-hour time-weighted average exposure of 50 ppm. Although they do not believe methylene chloride is a carcinogen, producers caution users to limit exposure to the paint stripper for other reasons. Methylene chloride metabolizes in the body to form carbon monoxide and, therefore, can reduce the blood's ability to carry oxygen, cautions Risotto.

However, doubling OSHA's standard would allow wider use of methylene chloride as a paint stripper. And although use of methylene chloride may not be as widespread for paint stripping in the future, "There may be some life yet in methylene chloride," says one industry source.

Until that happens, manufacturers and users of paint strippers have a number of alternatives. Just as it has been in the forefront of advanced aerospace paint technology, the U.S. military has had technicians investigating a number of paint-stripping alternatives. According to an industry source, the Navy and Air Force have evaluated various methods for stripping paint, including blasting with dry ice, cornstarch pellets, and water. Another technology under investigation is the use of enzymes to "pop-off" a paint top coat.

A. D. Little's John Martin adds wheat starch and walnut shells to the list of paint-blasting alternatives. One industry source warns that sandblasting may work to clear paint on heavy steel marine vessels, but aluminum aircraft skins are very thin, and sandblasting would quickly punch holes in such thin metal.

Chemical stripping alternatives, however, are widely available. The Turco Products Division of Elf Atochem, Philadelphia, offers three proprietary formulas for removing paint from aircraft. These strippers are "free of all chlorinated solvents, phenolic compounds and derivatives, ozone-depleting chemicals, and hazardous air pollutants" says aircraft aerospace accounts manager Donald DeHaye. The strippers are also "low in VOC [volatile organic compound] emissions," he says, and require no special or extraordinary waste treatment like methylene chloride does.

The Turco strippers, DeHaye says, consist of "non-HAP [hazardous air pollutant] solvents, activators, and corrosion inhibitors," but they are chromate free.

Other providers of chemical strippers are not nearly so shy in talking about the alternative active ingredients they offer to paint-stripping formulators. Gary S. Winfield, a Monsanto market development manager based in Springfield, Mass., says dimethyl esters make excellent paint strippers. "People want environmentally friendly products. Dimethyl esters have low toxicity, little corrosive effect on metals, no odor, and they are not expensive." Although they are VOCs, dimethyl esters evaporate very slowly from a stripper, says Winfield, posing less of a problem in atmospheric smog formation than solvents that evaporate faster.

Winfield does admit, though, that "nothing is better than methylene chloride to strip paint." But dimethyl esters, a coproduct stream from the adipic acid Monsanto makes for the manufacture of nylon fiber, "are not as hazardous [to people] as methylene chloride." Formulators can easily use dimethyl esters to make water-based gels and pastes, which, although they may work more slowly than methylene chloride, do not evaporate as fast and thus have a longer useful life.

Monsanto is a fairly recent entry into the U.S. dimethyl ester market. DuPont has been offering a more refined ester, a dibasic ester that is a by-product of its manufacture of adipic acid. Lisa Boothe, business and marketing manager for DuPont Nylon, Intermediates & Specialties, says use of dibasic esters for stripping has grown gradually. Most formulators and consumers still seem to prefer methylene chloride as long as they can get it.

Another chemical alternative for paint stripping is N-methyl-2-pyrrolidone (NMP). Three manufacturers supply most of the demand for the product: ISP, Wayne, N.J.; BASF; and Arco Chemical. "Historically," says one industry source, "NMP has been used as a cosolvent in paint and coating formulas. However, it has tremendous potential in paint stripping. [Its use] will continue to grow as people formulate paint removers that do not contain methylene chloride."

Although it is a VOC, NMP has extremely low volatility at room temperature, so it does not contribute to global warming or smog formation. It is a highly effective solvent and essentially is safe for workers to use, says a BASF spokesman.

Daniel Pourreau, performance chemicals technical services manager for Arco Chemical, says NMP also works as quickly as methylene chloride to strip alkyd paints, but it is slower than methylene chloride on epoxies and polyurethanes. One major advantage NMP has over methylene chloride is its ability to selectively strip graffiti from a polyurethane-painted surface, says Pourreau. Because NMP works faster on the alkyd spray paints most graffiti artists favor, the chemical attacks the graffiti quickly and can be washed off before it destroys the polyurethane coating.

Methylene chloride, however, still has its champions. Its use is diminishing not because it does not perform well, but because EPA and OSHA consider it a problem. "The government is my best salesman," says Monsanto's Winfield.

Architectural coating makers balk

Not all sectors of the paint industry can agree on ways to reduce their contribution to air pollution. Producers and users of aerospace, marine, and wood furniture coatings have agreed on ways to reduce emissions of smog precursors and hazardous air pollutants (HAPs) from paint as it dries. But producers of architectural and industrial maintenance paints are still at loggerheads with the Environmental Protection Agency.

EPA, industry sector agree on VOC limits for wood furniture coatings

Negotiations on the question among paint manufacturers and users, EPA, and environmental groups collapsed about a year ago. The groups could not agree on specific limits for volatile organic compounds (VOCs) - precursors of atmospheric smog - for more than 50 categories of paint, which account for 65% of all paint sold by volume. They also could not agree on a timetable to put those limits into effect.

Many paint material suppliers have introduced new materials to help formulators comply with existing state and pending national rules on limiting VOCs in paint. But the time required to test and qualify new materials and to prove new formulations is costly.

When talks collapsed last year, negotiators involved with setting national VOC-reduction targets for architectural and industrial maintenance paints had before them a set of proposals. The group was looking at a set of limits that would have reduced VOCs emitted from paints in the category by 25% beginning in 1996, 30% by 2000, and 40% by 2004 - all based on 1990 emission levels of about 990 million lb.

EPA and the paint industry, represented by the National Paint & Coatings Association (NPCA), are now fairly close on a 1996 round of limits that would reduce VOC emissions about 20% in NPCA's proposal and 25% in EPA's proposal from the 1990 level. However, NPCA opposes a second set of rules proposed by EPA for 2000 to force a 35% reduction from the 1990 base. EPA has dropped its proposal for a third set of VOC reductions for 2004.

NPCA's Robert Nelson, director of environmental affairs, says he is particularly concerned about EPA's proposal for 2000. "If the proposal looks like it does now, then we have problems," he says. EPA's proposal includes an emissions trading program that Nelson says is unwieldy and complex. The trading program replaces a VOC "exceedance fee" provision that EPA dropped in the face of loud industry opposition.

"We are lobbying heavily to get rid of the table of standards for the year 2000," says Nelson, as well as the complex trading rules. Nelson adds EPA recently indicated it might be flexible and not immediately impose standards for 2000.

The stakes are high for paint makers. Once EPA issues final rules on VOCs, the industry expects many states to adopt the rules so they can meet fast-approaching Clean Air Act deadlines to improve air quality in population centers. Many states have begun to develop their own VOC rules for the paint industry. That is a situation Nelson and NPCA want to head off. Paint makers do not want to see a welter of different regulations from state to state that would force them to go to the extra expense of making different formulations for different states.

"There is a lot of rule-making activity going on at the state level [that] we want to avoid," says Nelson. A number of states - including Oregon, Louisiana, Indiana, and Kentucky - were on their way to developing their own VOC limits on paint. NPCA and its members have so far been able to convince state regulators to wait for the federal rule. The longer it takes EPA and paint makers to iron out their differences, the more difficult it will be for paint makers to avoid having to deal with a number of different state VOC standards.

Although some segments of the paint industry would argue that environmental regulations of all kinds are unnecessary, VOC regulations are already a reality in states such as California, New York, and New Jersey. Other states will follow. Paint material suppliers say they are ready to do their part to help formulators comply with the coming regulations.

Dow Chemical's Robert A. Spurling, North America marketing manager for oxygenated solvents, says the drive to lower VOCs makes solvents seem like "just so much regulatory baggage." Wherever they can, paint formulators are trying to replace VOCs and HAPs with water. As a result, "we are seeing an uptick in demand for glycol ethers." A relatively small amount of these oxygenated solvents in water-based formulations provides the solvency necessary to make a paint system work, notes Spurling. Although they are themselves VOCs, their use helps lower the overall VOC level in a paint formula.

Spurling says he expects to see hydrocarbon and chlorinated solvent use decline over the next five years. But he expects the use of more active oxygenated solvents - alcohol, alcohol esters, and propylene glycol ethers - to grow. The only oxygenated solvents to show some decline in usage will be the ethylene-based glycol ethers, he predicts, because they are considered HAPs.

Dow supports liquid-paint formulators' move to low-VOC solvent systems that use Dow's P-series glycol ethers. The company offers customers the use of its computer solvent-modeling system to aid in the switch. The computer system can "cut from a few days to one hour over the phone the time required to design a solvent system that reduces the use of hydrocarbons and substitutes glycol ethers," says Spurling.

Arco Chemicals' Daniel Pourreau agrees with Spurling in expecting increased use of P-series glycol ethers by the paint industry. These glycol ethers should see increased use as "coalescents and coupling agents for resins in water," he says. Arco recently expanded its line of glycol ethers with propylene glycol monoethyl ether and its acetate, propylene glycol n-propyl ether, and dipropylene glycol n-propyl ether.

A Union Carbide spokesman also notes that paint formulators are moving away from hydrocarbon solvents and are using more oxygenated solvents. The company sells a variety of solvents such as oxygenated ketones and butanols. It also licenses an alternative paint-spray system that substitutes supercritical carbon dioxide for some of the solvent. The supercritical carbon dioxide acts as a diluent in high-solids paint and allows users who purchase and use the Unicarb system to spray otherwise viscous high-solids paint.

Still another alternative solvent is p-chlorobenzotrifluoride, trade named Oxsol 100, from Occidental Chemical. According to Diane Tramontana, an OxyChem business manager, Oxsol 100 is a VOC, but EPA and at least 19 states have proclaimed the solvent exempt from VOC regulation. Oxsol 100 is "not photochemically reactive," says Tramontana, and thus does not contribute to atmospheric smog. It is, she says, "an ideal molecule, like ethane. It lasts long enough to escape the local air dome, then it breaks down before it can become a problem in the upper atmosphere." Two other solvents that fit the same definition are acetone and dimethyl siloxane, she says.

Resin producers are also working to adapt their products to perform well and require less solvent. Thomas M. Dyott, coatings business director for Rohm and Haas, says the company continues to work on water-based acrylic resin systems for industrial maintenance paints. Water-based acrylic emulsions have already taken a major share of light- to medium-duty industrial applications such as storage tanks and bridges, he claims. Along the way, they have displaced older, high-VOC, solvent-based paint systems.

"A few years ago, we developed the first resins for solvent-free architectural paints," says Dyott. Many consumers are interested in the development of such low-odor paints for interior use in schools, hospitals, and nursing homes, he says. "New polymer morphology allows us to do away with solvents and still get good film formation," Dyott says.

Bert Mukkulainen, an Air Products market manager, says the company has a new line of vinyl acetate ethylene emulsions to allow formulators to eliminate cosolvents in a formulation. Sold as part of an experimental series of emulsions, Airflex 808 and 809 permit formulators to manufacture paints with no odor as they dry and with a VOC profile of about 0.4 lb per gal, Mukkulainen says.

Air Products also makes a line of urethane prepolymers to help coatings formulators lower the VOC contents of polyurethane solvent-based systems. Steven Burks, industrial coatings business development manager, says the company's Airthane PCG 475A urethane prepolymer allows a paint maker to manufacture a primer with a VOC level of 2.8 lb per gal. He says Air Products has lab tested a companion urethane prepolymer for top coats, Airthane ASM 540M, in a formulation with 2.3 lb VOC per gal. The two Airthane prepolymers perform well on ships, bridges, industrial pipes, and tanks, he says.

Angus Chemical, Buffalo Grove, Ill., offers two new low-viscosity reactive diluents for use in high-solids polyurethane paint systems. Thomas L. Johnson, commercial development manager for the company, says both Zoldine RD20, an oxazolidine, and Zoldine RD 4, a hybrid oxazolidine, can replace more than 20% of a paint system's high-viscosity acrylic, polyether, and polyester polyols. The replacement polyols contain few or no VOCs and thus lower the need for solvents in the paint, says Johnson. Solvent-borne polyurethane paints with only 2.8 lb VOC per gal are possible with the new diluents without any loss of performance, he says.

Ryan R. Dirkx, catalysts business manager for Elf Atochem, says the company's line of Fascat organotin catalysts are an aid in the trend toward lower VOC coatings. The catalysts effectively speed the cure rate of alkyd, polyester, and urethane coatings in both waterborne and high-solids, low-solvent paint systems.

Scientists at Cytec have developed an aliphatic isocyanate for two-part waterborne polyurethane paint systems, says Cytec's Robert S. Berger, marketing and sales vice president. This new isocyanate in the Cythane product line "is quite a novelty," says Berger, because not only is it stable in water, but it also does not require additional cosolvents to reach a suitable viscosity for application. As a result, paint formulators using this advanced aliphatic isocyanate can produce a very low-VOC coating material, he says. It is, however, 15% more expensive than existing waterborne aliphatic isocyanate polyurethane systems, he adds.

Hüls America, the Piscataway, N.J.-based affiliate of German chemical company Hüls, produces additives for powder coatings. It has developed a new internal blocking cross-linking agent for polyurethane powders. Vestagon EP BF 1300 is an isophorone diisocyanate-based material designed to eliminate the small amount of VOC emissions from the &egr;-caprolactam external blocking cross-linker typically used for polyurethane powder coatings, says Peter Toohey, coating raw materials marketing manager. Commercial quantities of the new agent will be available after Hüls receives government approvals, he says.

"Radiation-curable coatings are the way to go to reduce VOCs," declares Paul Elias, business manager for Sartomer, based in Exton, Pa. The company, a division of the French oil and chemical company Total, sells monomers, oligomers, and the photoinitiators required for radiation-curable coatings, which give off "essentially no VOCs as they cure," he says.

Still, Elias would have to admit that even as some paint users may adopt radiation or powder coatings, others will hold fast to more familiar - and generally less costly - liquid-coating technologies, even if it means enduring some pain to reformulate.

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