Polyurethane Power

By Christine Esposito | August 9, 2005

With polyurethane technology, manufacturers can create coatings, adhesives and sealants with superior performance and aesthetics.

When it comes to coatings technology, there are a few factors your customers keep in mind: price, appearance and performance. While the former is a major concern-especially in today's economic climate-it can't be the only factor a company bases its choice on when it comes to protecting its most valuable assets.

"If you stand back a bit from the woods of these economic problems that we have today, the trends are very clear and that is we are continuing to go towards environmentally-friendly coatings and more performance-based coatings," said John Williams, president, coatings and colorants division, Bayer. "When people paint an object, they want it to provide not only good appearance, but some lasting protection. It doesn't matter if it's a car, a bridge or a file cabinet."

Suppliers to the industry contend the combination of performance and environmental pressures make polyurethane coatings a premier technology for a wide number of products. They must be right: several companies-and even military organizations-have employed polyurethane-based products to serve their diverse markets and customers. Take U.S. Paint, which last year unveiled AWLGRIP 2, a high-solids polyurethane exterior topcoat for the aerospace industry that offers the same high gloss and image as conventional solids products. More recently, Sherwin-Williams was awarded a U.S. patent (No. 6,191,213) for penetrating stains and sealants from polyurethane dispersions. And at the 2001 International Waterborne, High-Solids and Powder Coatings Symposium, J.A. Escarsega presented "DOD applications utilizing water-reducible camouflage coatings," a paper that provided details on the U.S. Army and Marine Corps' use of polyurethane coatings as a camouflage topcoat for its tactical vehicles and aircraft.

"In terms of performance, urethanes are always considered to be top of the line in terms of corrosion resistance, weather stability, scratch resistance and so forth," said Dr. Williams. "Urethanes have always proven to be high performance. But more importantly, now there are all of the environmentally friendly aspects too."

Statistics released in 1999 by The Alliance for the Polyurethanes Industry (API) place the polyurethane coatings market in the U.S. and Canada at 547 million pounds, which accounts for just nine percent of overall demand for polyurethanes. Polyurethane adhesives account for four percent of the overall market and sealants account for three percent, according to API. Within polyurethane coatings, the two leading end-use areas are construction and transportation, accounting for 30% and 29% of the market respectively.

"Higher performing coatings providing superior durability and weatherability are especially important for exterior and industrial coating applications. Polyurethane coatings are long lasting which in turn saves money in maintenance and recoating costs," said Ken Bourlier, commercial development manager for Rhodia's industrial coatings business.

Although transportation and construction markets account for the bulk of polyurethane coatings used in the U.S. and Canada in 1998, they are areas that remain full of potential, according to Huntsman Polyurethanes America. "The construction and transportation market offers the largest opportunities for polyurethane in terms of benefits for coating manufacturers, primarily due to the market sizes and increasing customer demand for better performance features from coating products," said Michael Hughes, adhesives, coatings, elastomers marketing manager at Huntsman Polyure-thanes America.

When it comes to building multi-million dollar sports stadiums or promenades to revitalize a downtown area and attract tourists, the stakes are high for all involved. For the owners, protecting the facility and keeping up appearances in a major concern. According to some in the industry, specification of polyurethane coatings is a smart move.

"In new construction it is a value-add to put a polyurethane on rather than other generic types of coatings," said Dr. Williams of Bayer. "It adds not only to the appearance but to the endurance, and the long-life of the structure." This was a choice made by the designers of the San Antonio Walk. Polyurethane anti-graffiti coatings are used at the site to protect the facility from vandalism.

On the automotive front, with the help of PPG, General Motors made the switch from a one-component clearcoat finish on its Astro and Safari vans to a 2K etch-resistant polyurethane clearcoat. Etch-resistance might provide an avenue for growth for polyurethane technologies in the automotive industry. "Polyurethane coatings provide unmatched exterior durability and weatherability for the transportation industry. In the automotive industry this is becoming increasingly important when protecting cars from the harsh environmental elements such as acid rain," Mr. Bourlier said.

New Niches, New Markets for Growth
According to Frost & Sullivan, sales of polyurethane coatings in Europe are expected to rise from $3.46 billion in 1999 to $3.85 billion by 2006. With an annual compounded growth rate of just 1.5%, the market appears to have hit a plateau of sorts, forcing market leaders to seek new avenues of growth. "Most companies see their main new markets for polyurethane coatings as being in the developing countries, and have expanded in eastern Europe, Asia or South America as a means to increase their sales," said Robert Peacock, an industry analyst with Frost & Sullivan.

Johan Van Tongelen, commercial manager, adhesives, coatings and elastomers, Huntsman Polyurethanes, said companies are also delving deeper into niche applications. "In the European market, we are now seeing the emergence of niche markets, offering companies new opportunities to achieve growth and increased profit margins." According to Mr. Van Tongelen, key niche areas emerging in Europe include protective building and civil engineering, offshore and general industry coatings. "Manufacturers are already developing technologies ranging from polyurea spray coatings and elastomeric coatings, including noise and vibrating damping applications to provide tailored solutions to meet the special requirements of these applications."

One market that has not yet fully embraced polyurethane technology, however, is the U.S. wood industry. "In the U.S., the wood coatings market segment still represents a growth opportunity for polyurethane technologies," said Dan Pourreau, coatings development manager, Lyondell. "In contrast to Europe and Asia, where 2K urethanes are commonly used to coat wood furniture and cabinets, U.S. manufacturers still rely heavily on nitrocellulose lacquers and baked alkyds. Urethane technologies are beginning to make inroads in this market, especially low-VOC waterborne and UV systems."

Raw Material Developments
Suppliers to the polyurethane market have been busy in the lab, tweaking performance and creating new products to suit the needs of coatings manufacturers looking to offer their customers top-notch polyurethane-based coatings, adhesives and sealants.

New from Huntsman Polyurethanes is Rubinate 9513, developed for use as a primer to be used with spray polyurea. "A key benefit is that it can be re-coated before it cures," Mr. Hughes said. The product is also an effective primer for polyurea on wood, metal and other surfaces.

Huntsman has also developed a new range of products that address the specific demands of flooring applications. Among these products are Suprasec 2496, a low-viscosity polymeric MDI product which presents good liquidity after prolonged storage at temperatures below 5�C, according to the company. The product, which also provides additional benefits including adjustable elasticity, excellent abrasion resistance, waterproofing properties and flexible curing times, can be used in primer, pipeline coatings, roofing membrane and general industrial adhesive applications. The Suprasec range also offers products that can be used as a direct replacement for existing technology in wire coatings formulations in the electronics and telecommunications industries and provide improved durability, excellent adhesion and cut resistance as well as high elongation and flexibility.

One of newest PUDs on the market is based on a technology patented by Alberdingk Boley, which bases polyurethane dispersions on castor oil."Because castor oil PUDs give different combinations of performance properties, they have the ability to either open up new markets or improve performance in existing markets," said Michael O'Shaughnessy, vice president sales and administration, Alberdingk Boley.

"The most common PUDs in the market are polyesters. This is a good technology that is tried, true and proven. The market however is advancing and looking for polyester PUDs that are harder, have lower levels of NMP and improved resistance properties," he added. "There are still some right and left hand turns you can put on the polyester PUD chain to eke out a little better performance, but many applications require more than a little improvement."

According to Mr. O'Shaughnessy, when a formulator works with castor oil-based PUDs he has the "ability to make very hard systems that have much lower levels of NMP when compared to conventional polyesters. The polymer is based on castor oil so it has improved water resistance when compared to conventional polyester PUDs and is completely non-yellowing. Castor oil diols also allow us to create a polymer with higher crosslink density that is not brittle because it is internally plasticized," he said.

Lyondell has recently developed two low-viscosity isocyanate adducts to replace existing systems. HA-300 and HA-500 combine lower viscosity, improved dry-times and hardness, and lower cost than existing low viscosity versions of HDI trimer, according to Kiran Chandalia, commercial manager, aliphatic isocyanates. "We have also developed solutions of our traditional HDI and IPDI adducts in TBAc in anticipation of TBAc's VOC exemption." Lyondell is also developing new, internally blocked isocyanates that "contain no free isocyanate groups yet unblock under mild conditions to give high performance urethane coatings without emitting volatile by-products."

Lyondell is also working on new moisture-cured coatings technology that "significantly reduces the potential for isocyanate exposure," said Mr. Pourreau. The prepolymers are based on Lyondell's HD-100 dimer and Acryflow P120 and P130 liquid acrylic polyols. "Because HD-100 has significantly lower volatility than the monomeric diisocyanates typically used, the potential for isocyanate exposure is significantly reduced. In addition, the prepolymers are liquid at 100% solids and cure rapidly under ambient conditions to give hard, weatherable urethane coatings suitable for floors, decking, and other industrial maintenance applications," he said.

As manufacturers come face-to-face with new substrates to coat-each requiring different adhesion and wetting additives-proper formulation is a must. "Each polyurethane technology is being asked to do things in markets and applications that it can't presently do," said Bruce Waldman, global business manager, coatings, adhesives, sealants at OSi Specialties, a Crompton business. "As an example, polyurethane dispersions are being used in many applications typically reserved for solvent-based coatings. This can create a challenge with respect to chemical resistance, wetting of the substrate and a number of other issues." OSi Specialties offers CoatOSil 1211 additive, which even allows a waterborne coating to wet Teflon. The silane will crosslink a PUD, giving final chemical resistance similar to that of aziridine, Dr. Waldman said.

Crompton's Uniroyal Chemical business also offers Witcobond aqueous polyurethane dispersions and Fomrez polyester polyols for polyurethane coatings, adhesives and sealants. The dispersions provide high-performance alternatives to current solvent-based urethane formulations where conventional spray or roll coating is used, according to Jeff Gault, worldwide market manager, Urethanes Technology Group.

For adhesive and sealant applications, Rhodia offers a new range of "specially designed" waterborne aliphatic polyisocyanates that are self-emulsifying in water and give "outstanding thermal resistance for wood-to-wood bonding, PVC laminates, footwear and automotive applications.

Also on the adhesives front, Vantico has played a significantly role in helping Leer Division, Elkhart, IN be able to fabricate a new tonneau cover for pick-up trucks. Vantico's Arathane AW 8680/HW 865 polyurethane was chosen by the company for its 10-minute gel time and its ability to bond Telene thermoplastic panels and ABS.

Alliances, Acquisitions Can Improve Technology
Earlier this year, The Dow Chemical Company made an acquisition that improved its position in the polyurethane market. Dow acquired the $500 million polyurethane business of EniChem S.p.A., giving it its first source for TDI in Europe. "We are strongly committed to this industry and not only does this agreement give us our first European source for TDI, it also enhances our MDI, glycol and polyurethane systems capability," said David Fischer, Dow business vice president, polyurethanes. With EniChem's polyurethane business, Dow's adds 118,000 metric tons of TDI capacity, 80,000 metric tons of MDI capacity and 160,000 metric tins of polyols capacity to its stable.

As this issue went to press, a new alliance in the industry was established for coatings manufacturers looking for novel solutions to their polyurethane formulation needs. Johnson Polymer has entered into a global technical and commercial alliance with Essential Industries of Merton, WI. "Essential Industries offers unique polyurethane chemistries that when combined with Johnson Polymer's market reach and applications strength, will bring exciting new products to the coatings market," said Kees Verhaar, president and COO of Johnson Polymer.

According to Dana Johansen, who has managerial responsibility for the Essential Industries/Johnson Polymer Alliance, combining expertise is what has helped catapult coatings technology to a level well beyond that which was available only a decade ago-and polyurethane technology has played a major role. "While the resin and isocyanate suppliers continue to make improvements in the technology the customers continue to raise the bar with regard to performance-ultimately delivering better products than were available even 10 years ago," he said.

Many in the industry contend as long as environmental issues and regulations remain paramount concerns, polyurethane technologies will be employed by savvy companies looking for long-range, high-performance protection for their most valued products and facilities.

"The single greatest factor affecting the polyurethane coatings market is the health safety and regulatory movements afoot globally," Mr. Johansen said. "Looking at the available chemistries out there, polyurethanes offer the best, most cost effective and sometimes only answer to solving specific issues. Since it is the function of a coating to ultimately protect an asset, PU chemistry, which is a combination of resin and isocyanate development, offers the coatings formulator the most flexible group of tools in their formulating toolbox."

For more information on the polyurethane market, visit the Alliance for the Polyurethanes Industry web site: www.polyurethane.org.

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