Although it is considered a niche market in terms of size and demand as compared to other types of inks, screen inks have many different uses. From automobile instrument panels and labels on packages to personalized t-shirts and compact discs, screen inks are popping up all over the place.
According to the Screenprinting and Graphic Imaging Association International (SGIA), the U.S. screen printing industry is valued at $60 billion, with more than 30,000 screen printers in operation throughout the country. Described as a very diverse industry, screen ink manufacturers have seen screen inks become more technologically advanced and inks for many different substrates be developed.
“Back in time, screen printing was really an advanced form of art, and was considered more of a type of arts and crafts,” said Harold Johnston, vice president of sales, Nazdar, Shawnee, KS. “It then evolved to the point of automation and photomechanics. We have in-line printing unlike any other, and can print on almost anything.”
In screen printing, the type of ink used is determined by the substrate being printed on. “The beauty of screen printing is its flexibility,” said Christopher M. Morrissey, vice president of sales and marketing at Sun Chemical. “If one can find a surface to decorate, screen printing will accommodate it.”
Among the areas that screen printing is being used for are decal and labels, indoor and outdoor signs, markings, billboards and displays, automotive glass, flat glass, compact discs, bottles, OEM, electronics, and textile applications.
“One of the largest segments is advertising billboards, which you see everyday,” said Mr. Morrissey. “Another popular user of screen printing includes the automotive industry. The pattern printed is a solid band along one side that becomes a series of dots or stars in its other border. The strip is found around the edge of windows on many cars. Screen printing is also used on the instrument panel to indicate various dials and gauges.”
“In the past, screen inks were primarily used in the graphic arts industry for point-of-purchase displays, water applied decals, pressure sensitive decals and other advertising and sales markets,” said Dave Knoll, president, Cudner and O’Connor Company, Chicago, IL. “Additionally they found applications for outdoor signage, container decorating, printed circuitry and textiles. Over the past 15 to 20 years, there has been an increase in the use of engineering grade inks such as epoxies, polyurethanes and polyesters. These inks are used for industrial applications in the nameplate, appliance, automotive, decorative and architectural glass industries.”
With the screen printing market being so diverse, manufacturers tend to focus on developing screen inks for a few different applications. “Although many screen ink manufacturers offer an ‘all-purpose’ screen ink or a ‘multi-purpose ink,’ including ourselves, the wide variety of substrates and product performance generally demands specific inks for specific applications,” said Mr. Knoll.
In the U.S., Sun Chemical focuses on the label market with the SUNSILK line of UV screen inks. “In Europe via several members of our group, including the Gibbon Group in the U.K. and our Spanish operation, Sun Chemical supplies inks and coatings for a variety of screen printing applications,” said Mr. Morrissey.
Cudner and O’Connor’s strongest niches are in the appliance, automotive, architectural and decorative glass, and nameplate markets. “We also manufacture screen inks for virtually all screen printing applications with the exception of textiles,” added Mr. Knoll.
Colorcon, West Point, PA, manufactures screen inks for temporary tattoos. “The high volume temporary tattoo business is generally printed lithographically, but the smaller, more specialized orders often go to silk screeners,” said Jerry Napiecek, manager of technical services for specialty products and no-tox products. “Typically these tattoo inks are lacquer type formulations using cosmetically acceptable pigments for coloration.”
Types of Screen Inks
Like other printing operations, screen printers can choose their ink of choice from a number of types, including solvent-based, water-based and UV. In most cases, the type of ink used will be determined by the application.
Unlike other printing applications where water-based inks are becoming more and more popular, they do not offer all of the qualities needed for screen printing. “Water-based applications are very unpopular,” said Mr. Johnston. “They are limited in applications. There was the connotation that water-based inks are environmentally friendly, but the drawback is that they are not as productive as solvent-based inks.”
In terms of durability, solvent-based inks are still the preferred choice. “The two primary reasons for an increase in popularity of UV inks for screen printing is the lowering of VOC emissions and the ability of UV inks to offer substantially increased production rates,” said Mr. Knoll. “But UV inks in their current state are limited in regards to issues such as durability, particularly in the automotive and appliance industries. In terms of overall durability, solvent-based inks are still champions.”
“Solvent-based inks are still very important in industrial applications and signage,” said Michael Fox, Nazdar’s president. “But there continues to be a trend to move towards UV inks and away from solvent-based inks. UV inks have become a greater portion of the total amount of screen inks manufactured, and this amount continues to increase. UV screen inks offer higher reproduction consistency and resolution quality.”
UV Screen Inks
According to Mr. Morrissey, UV inks account for approximately 90 percent of the marketplace in the non-textile screen printing market. He said printers originally looked at UV as an environmentally-friendly product, but have stuck with UV because of the many performance advantages it offers versus solvent- and water-based screen inks. “Initially, environmental considerations were the big reason,” said Mr. Morrissey. “But as more and more printers experimented with the technology, they found out the true benefits of UV technology. Printers were able to ship high quality jobs immediately after printing. The productivity increased drastically. Press operators produced jobs instead of worrying about drying of the ink during printing process or during their lunch break.”
Even though there is a lot more to gain by using UV screen inks, the initial cost to make the switch can be high. “UV technology requires a major investment in equipment, including a UV curing unit,” said Rick Holmstrom, COO, Nor-Cote, Crawfordsville, IN. “UV inks tend to be more expensive in terms of price per gallon compared to standard solvent-based inks, but they get more coverage.”
“In terms of total application, the applied cost for UV screen inks is lower than that of standard solvent-based screen inks,” said Gary Fullem, Nor-Cote’s national sales manager. “UV screen inks offer more durability, higher chemical resistance and higher gloss.”
Another advantage to UV screen inks is the amount of space that the equipment requires. To screen print with UV inks, all that is required is an UV press, which has multiple stations that complete the operation. Ovens and drying racks are not needed when printing with UV screen inks. “With solvent-based inks, you would need a 300 to 400 foot machine,” said Mr. Johnston. “With UV inks, the screen printing can be done much quicker and with limited space requirements.”
“UV inks cut down on floor space and man power required,” said Mr. Fullem.
Nor-Cote recently introduced a new UV screen ink for the container market, offering high gloss and high chemical resistance. “It is a material that is taking off very well,” said Mr. Holmstrom. “You do not have to add any other material to this ink, and it cleans up very well.”
Although n-vinyl pyrrolidone (NVP) is not as much of an issue in North America as in Europe, Nor-Cote has developed NVP-free inks. “NVP is not a hazardous material in North America, but the UK and Europe are becoming more sensitive to NVP,” said Mr. Fullem. “This new ink is NVP-free. We are taking the approach that all of our new products will be NVP-free.
“We also have new inks for CDs with improved rheology and better on-screen performance,” added Mr. Fullem.
Another new introduction from Nor-Cote is an in-mold decorating ink for appliances, automobiles and electronic equipment. “We had attempted to launch this product before, but the market wasn’t ready for it,” said Mr. Holmstrom. “We made some minor adjustments over the past few years, and it is now getting good results. It is a replacement for slow drying, solvent-based systems.”
Nor-Cote expects to see increasing demands for UV screen inks, both in the U.S. and abroad. “Asia is growing rapidly, particularly in the tag and label and CD markets,” said Mr. Fullem. “We also expect to see some growth in South America over the next few years.
“We are finding more and more opportunities for UV screen inks as the market expands,” Mr. Fullem continued. “The level of sophistication of the user and the applications has grown as UV screen inks grow in popularity.”
Last year saw a number of mergers and acquisitions in the ink industry, and one acquisition should impact the screen ink market. Sun Chemical signed a letter of intent to purchase Coates from the TotalFina Group. “Coates is a global supplier of screen products,” said Mr. Morrissey. “When the acquisition is completed, it is expected to complement Sun Chemical’s product range.”
Screen ink manufacturers are constantly searching for new technologies and products to offer their customers, in hopes of increasing the popularity of screen printing. “The screen market is changing drastically with the introduction of ink jet technology,” said Mr. Morrissey. “We have already seen an investment by our customers in this technology. It will take several more years to improve the ink jet technology to bring it up to the standards of screen printing.”
Another possible alternative to existing technologies is EB inks. “EB screen inks are less expensive because you do not need the photoinitiator,” said Mr. Holmstrom. “This ink has great potential. We are seeing a dramatic decrease in cost-curing agents. EB inks offer 100 percent through-cure. Printers will continue to use UV inks, with the final stage consisting of an EB curing agent to cure the entire project. It is a simple conversion for ink manufacturers, but a high-cost factor for printers.”
“The fact is screen printing is a very precise yet relatively slower printing process,” said Mr. Morrissey. “The process is more labor intensive than a web-fed printing process like flexography. Therefore, press speed and efficient ways of handling the printing process are the main areas where the technology needs to be advanced.”
“More and more four-color presses for UV are being set up,” said Mr. Fox. “With UV inks, you can print four or five colors right in a row, and eliminate a lot of handling. This is a trend that isn’t new. We want screen printing to compete with offset, and we think that screen printing can offer higher run sizes and be more productive.”