A wood-shelving manufacturer reduced drying time for its wood panels from two days to one hour with a technology that is expected to grow up to 10% per year until 2001: radiation-cured coatings.
The faster the panels dry, the quicker the products get produced. This increases the overall plant productivity and makes Jacksonville, IL.-based Lundia a significant sum of money.
By switching from lacquer-based finishes to radiation-cured coatings, Lundia also eliminated volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) from the processing of nearly eight million board feet of wood per year.
Radiation-cured coating, also known as UV/EB curing, employs a cocktail of monomers and oligomers that are polymerized using either electron beam (EB) or ultraviolet (UV) light. The UV/EB process is often called radiation-curing because UV and EB are radiant energy sources.
A "liquid plastic" raw material forms rad-cure resins that harden instantly when exposed to ultraviolet light or accelerated electron beam. The process forms a coating with "an instantaneous cure, and the industry continues to develop high-purity, low-viscosity materials that have better adhesion to metal and plastics," said Steve Awadalla, marketing manager for Smyrna, GA-based UCB Chemicals, one of the producers of rad-cure monomers and oligomers.
UV/EB curing is widely used in inks, varnishes and paints. Evolutions in the chemistry behind this technology-which has been around since the 1970s-has made UV/EB an increasingly popular way to coat a wide variety of substrates including wood, paper, ceramics, metal, glass and plastics.
The growth of the UV/EB market is charted in this report. A market analysis follows.
Total volume of UV/EB curable products now approaches 110 million pounds per year or 55,000 metric tons, according to Kenneth Lawson, president of DSM Desotech, a consulting firm in Elgin, IL.
"The growth rate for UV/EB coatings has slowed to seven percent from its 10% clip over the past few years," explained consultant Michael Growney, a director of Caldwell, NJ-based Kusumgar, Nerlfi & Growney. "Rad-cure is still growing two to three times faster than the rest of the coatings industry.
"Graphic arts now makes up 40% of the UV/EB market and wood furniture accounts for another 20% of the market," Mr. Growney said. "There is nothing on the immediate horizon that will push rad-cure coatings past the seven percent growth rate."
According to a 1998 study from RadTech International-the trade group for the UV/EB industry-the 10 fastest growing markets for radiation-cured coatings include ink jet printing, solid modeling/prototyping, medical devices, fiber optics, UV-cured powders, adhesives, UV flexo inks and coatings, automotive applications, plastic coatings and electronics (See The Top Ten Products, p. 30).
Converting to UV/EB
The outlook for growth in the rad-cure industry is being fueled by companies who are abandoning water- and solvent-based systems in favor of UV/EB. Making the conversion has many advantages:
•Improved productivity: Solvent-free UV/EB systems require less than a second of exposure, which allows for significant productivity gains.
•Suited for sensitive substrates: Most rad-cure systems don't contain any water or solvent. UV/EB curing provides total control of the cure temperature, allowing the technology to be used on heat-sensitive substrates.
•Environmentally- and user-friendly: The UV/EB process is usually solvent-free and virtually eliminates the issue of VOCs and HAPs.
•Space conservation: "UV curing equipment occupies less space than a conventional curing oven," explained David Harbourne, president of Gaithersburg, MD-based Fusion UV Systems, a manufacturer of UV curing equipment. "The curing that needs to be done in a 20 foot long conventional oven can now be completed in two feet of UV.
"UV needs to be given an opportunity to show its cost-effectiveness to end-users," suggested Mr. Harbourne. "For example, one pound of solvent-based ink is less expensive than one pound of UV ink-but UV ink is 100% solid. UV, therefore, is a better value for many applications."
Curing equipment costs between $5,000 and $750,000, and a plant needs three-phase power to operate a radiation-cured coatings system.
More Industrial Applications
Use of radiation-cured coatings had mainly been decorative; however the role of UV/EB has expanded to include more industrial applications, as the technology offers valuable properties that contribute more than just a pleasing appearance to products.
"Rad-cure coatings are penetrating in areas where they demonstrate a competitive advantage such as industrial applications," confirmed Minesh Kusumgar, of Kusumgar, Nerlfi & Growney.
A definite shift in the uses of UV is occurring, according to Mr. Harbourne. "UV is now being used in industries where the appeal is functional rather than just visual. It is used in the manufacturing process that produces Digital Versatile Discs (DVDs) and it doesn't make them look any prettier." A UV coating makes DVDs more durable, he said.
More than 200,000 DVD players were sold in Christmas 1998 alone and the market for DVDs continues to grow at a rapid pace. Since its introduction in April 1997, DVDs have caught on even faster than the compact disc did in its 1983 debut, or the videocassette players introduced in 1975 and 1976.
Other examples of this trend include:
• UV is used in protective coatings for the glass and optical fibers used in telecommunications cables.
• UV is used in the automotive industry to manufacture headlamp lenses to provide scratch resistance.
• Medical applications such as the bonding of cameras to syringes are done with UV coatings, an application that would be difficult with the more conventional high-heat processes.
• UV clear coatings are used to insulate and seal industrial pipes and tubes.
• UV's low heat has made it more valuable, as new sophisticated plastics require coatings. These plastics don't respond well to more extreme heat.
"Monomers and oligomers provide scratch resistance and optical clarity to eye glasses, goggles, face shields, audio, video and computer discs," added Mr. Awadalla.
"In wood products, epoxy, urethane and polyester acrylates are used as components in fillers for particle and fiberboard as well as coatings for fine furniture," Mr. Awadalla said. "They provide excellent mar, scratch and chemical resistance to both clear and pigmented topcoats and act as adhesives to fix paper to board stock. Clear varnishes, used in special spraying and curing equipment, provide protection and beauty to various furniture items for the home and office."
Some circuit boards include UV protective coatings to guard against dirt and moisture. Industrial applications will continue to grow as new raw materials with desirable properties are introduced and prices drop due to increased competition.
Raw Materials Competition
BASF and Akcros Chemicals have joined UCB, Sartomer and Henkel as players in the production of oligomers, monomers and photoinitiators for radiation-cured coatings.
Intense competition has decreased raw material prices by some five percent, experts suggest. Double-digit cost decreases are being reported regularly and a market that had very little free capacity to handle the growth of UV/EB technology is poised to take on the increasing demand.
"Raw material prices will continue to drop as more and more companies compete for market share," said Pat Foust, president, Craig Adhesives & Coatings, Newark, NJ.
In August 1997, Akcros brought a monomer and oligomer plant on-stream in New Brunswick, NJ. "Now there is excess capacity for UV and we are prepared to fill the demand as it increases," explained Joe Kosiner, Akcros' business manager for UV/EB curing resins.
Raw material innovation abounds as well. For example, BASF has introduced Laromer PE 55 F, a new polyester acrylate for UV-curable coatings to be used on wood, plastic, paper and printing inks.
"Most of the developments are in the oligomer area," said Mr. Kosiner. "If urethanes could be made more cheaply, they could be used on more applications such as overprint varnishes on magazines and brochures. Urethanes are commonly used in medical applications and on high-end goods."
Mr. Kosiner added that the possibility of incorporating a single oligomer is still a ways off. "We end up using two or three oligomers to achieve any given end-use application."
But new chemistries have eliminated odors from the rad-cure raw materials, lowered skin sensitivity, and have made materials bond better, all of which is good news for the industry.
"New raw materials with lower viscosity oligomers and better adhesion to different substrates are now in use and others are in development," said Mr. Foust. "On the Draize scale of skin sensitivity (0-8, 0 being the best), the new raw materials rate a two-much improved over the 1970s and 1980s."
"Object specific chemistry is what makes UV/EB so valuable," Mr. Foust added. "We have thousands of UV/EB formulations that have been customized for specific jobs, and the number of our customers that use UV/EB doubles each year."
The U.S. Clean Air Act and European efforts to achieve zero emissions of VOCs has forced the coatings industry to seek out new environmentally-friendly technologies. Rad-cure has been an answer for numerous applications.
In 1997, EPA head Carol Browner stated that UV/EB curing was a preferred method of coating because it eliminates air pollutants. In 1998, the South Coast Air Quality District of Southern California determined that using rad-cure would reduce VOCs, and has since taken an active role in encouraging industries to make a switch to UV/EB.
"Ultraviolet light-cured coatings not only reduced emissions to the EPA-required levels, but essentially eliminated emissions altogether," concluded Ms. Browner before the Senate Committee on Environment and Public Works.
The Limits of UV/EB
"Even with several decades of 10% annual growth, rad-cure remains limited to a number of relatively small volume specialty applications," Mr. Lawson explained.
When compared to the entire industrial coatings market of North America, the use of UV/EB represents about two percent of volume and four percent of the value of materials used.
There are still some markets where UV/EB technology has yet to make an impact, according to Fusion UV Systems' Mr. Harbourne. These potential markets include long-term, extra weatherability products such as outdoor siding. "We're probably a couple of years away (two to five years) from finding a way to change the chemistry of rad-cure so this application becomes possible with UV," explained Mr. Harbourne.
Another area is exterior/interior automotive finishes. Ideal monomer and oligomer formulations are elusive in this area. The UV spraying apparatus must be modified for this application as well.
Another obstacle to the growth of UV/EB is the capital invested in existing coatings systems.
"UV resins continue to grow at 10% per year but many clients still have solvent recovery systems that they spent million of dollars on,"" Mr. Kosiner suggested. "It will be a number of years before that equipment is paid down." n
Miles Z. Epstein is columnist for Hard Hat News, a construction industry newspaper that covers the paint and coatings markets.