Foil Applications

July 19, 2005

Of the many ways to decorate a package, foil - hot or cold - rises above the crowd.

Packaging must satisfy many demands in the marketplace. Chief among these are form, function, education, information, and aesthetics. The last of these — the visual appeal of the product and its package — is that which gets the juices flowing among brand owners, designers and (it is hoped) consumers.

Of the many ways to decorate a package, foil rises above the crowd. It glints, it shines, it makes a statement. On a wine label it speaks of nobility, grace, refinement. On a cosmetic product it speaks of luxury and quality. And on candies or entertainment products the message is that of fun.

Foil adds dramatic dimension to packaged products and labels. Why, then, is foil application equipment not found in every narrow web converter’s shop?

“My guess is that 10 to 15 percent of converters have the capability for foil,” says David Polkinghorne, president of DMS, a manufacturer of rotary hot stamp presses and dies in Lake Zurich, IL. “Probably 30 to 40 percent are in the prime label market, focusing mostly on health, beauty and beverage markets.”

One reason cited by converters for not entering the foil application arena is cost. Hot stamping equipment requires a significant investment, and if the customer base cannot be counted on to support such an outlay, the converter opts out. Foil stamping will add to the cost of a label, which often causes a budget-conscious customer to reconsider the choice. Many converters will decide to reach for the brass ring (or die, in this case) and install foil application equipment if a customer comes along whose work will cover the investment.

“A lot of converters want to get a job that will pay for the foil unit three times over before they buy it,” Polkinghorne says. “A lot of others are afraid to try something different.”

Foil application can be accomplished in several ways. Stand-alone hot stamping presses, such as those manufactured by Kensol-Franklin Inc., Newfoil Machines Ltd. and Rapid Packaging Services, are specialized machines that produce fantastic work and which can cost tens of thousands of dollars. The stamping dies, which cost little, are flat. Smaller units are also available.

Popular among narrow web converters in recent decades is rotary hot stamping. “The original units were built back in the mid-1970s,” says Polkinghorne. “Webtron built the first one that I’m familiar with. We started producing dies in the late 1970s for rotary hot stamping and embossing.”

Within the past 10 years, converters began to explore what is now called cold foil application. In just the past few years, cold foil has become a topic of serious discussion, and it looks as though interest in the process is spreading rapidly. A converter doesn’t have to write a big check to an equipment supplier for the cold foil process. It does take some planning and adjustments in the press room, and it might mean the addition of some equipment, but it falls short of the cost of rotary hot stamping, according to several industry practitioners.

Mike McDonough is co-owner of Flexo-Graphics, in Butler, WI. He was making inquiries over the winter about foil stamping equipment, but hadn’t settled on a process.

“We’re looking at it for one application,” he says. “This is driven by the needs of one customer. We’re looking at rotary hot stamping. We’re also considering cold foil as well, which we can get into with very little financial expenditure.”

Flexo-Graphics has seven Webtron presses, and McDonough says they would want the foil to be applied inline. “If I bought a rotary hot stamping unit and the customer liked the work, I’d probably get multiple units.”

Benefits and challenges
No one argues the benefits of foil to the product marketer. The aesthetic is there in full view — shiny and sparkling and making its statement.

Every day is foil appreciation day at converting plants that make wine labels. Foil on wine labels is a virtual requirement. Wine label papers present challenges to converters for several reasons, foil among them, but the customers need foil to make a critically important statement in the wine store and understand that the added expense is necessary to the movement of their product. (See our Wine Labels feature on page 38 of this issue.)

No, the benefits are not an issue. Instead, converters like to debate the disadvantages. Speed is one. Cost is another, both to the converter and to the customer. Waste is a third.

A Telstar cold foil unit mounted on a Mark Andy 4150 press

As far as speed goes, the numbers are all over the map. “Typically, rotary hot stamp presses run between 160 and 185 feet per minute,” says Tom Kirtz, president of Telstar Engineering, which manufactures rotary hot stamp units, die stations and other equipment.

“With speed, there’s a learning curve,” says Peter Kuschnitzky, general manager of I.Kela Co., Sarasota, FL. “It’s 50-50. Some customers can take it out of the box and run it at 125 feet per minute the first day. then a month later at 180-190 feet per minute. Others struggle.” In general, he says, average speed for rotary hot foil application is in the 150 fpm range, though “some are doing over 200.”

“Some of the release characteristics of hot foils have improved,” says Kirtz, “so that running speeds can get higher. It used to be hard to push a hot foil die over 150 feet, but they’ve gone up a notch.”

Polkinghorne of DMS says that wine label converters tend to run at slower speeds. “Where they’re using classic laid papers, they tend to run between 90 and 120 feet per minute on short runs. It’s fussy work.”

Press speeds for foil transfer will be different in every situation, most experts insist. Factors such as type and quality of substrate and complexity of the design will contribute to the speed factor.

Not everyone is stamping foil at under 200 fpm. Polkinghorne says that heavy duty systems can work at speeds above 400 fpm.

“Converters want more throughput, faster products, more labels per hour,” says Sam McElree, sales manager, graphics, for Kurz Transfer Products, Charlotte. “We come out with products that will run at higher speeds. We work closely with application machinery companies to develop products with faster release and better quality. You can’t sit still. It used to be that 200 feet per minute was fine, now they want 300 to 400 feet per minute.”

API Foils, Lawrence, KS, maintains that one of its recently introduced products can be applied at very high relative speed. According to Jennifer Hoyt, marketing manager, the company’s GR Series high speed rotary foil “is capable of print speeds in excess of 12,000 sheets per hour for sheetfed equipment, and 600 feet per minute for web fed machines.”

The company’s chemists, she says, “formulated it specifically for rotary applications. It has better temperature range, better release, and it goes faster on the press.”

The hot process
Hot stamping foils are composed of several layers. They differ by adhesive, by release coating, and by foil content. Some foils require a finishing varnish or overlaminate, some do not.

“There are a lot of differences in foils,” says Polkinghorne. “Some are better for papers, some for films. There are cutting issues, whether a material is good at filling an uneven substrate surface. If you have that property you have a tendency to bridge fine details. Others focus on the fine details.”

Conventional rotary hot stamping stations are similar to inline diecutting stations in that they utilize anvils to bear the pressure, and heavy rolls to press the foil onto the substrate. The amount of pressure required to properly apply stamping foil is far greater than that used in diecutting.

“It’s inappropriate to treat a rotary hot stamp unit like a print station,” says Polkinghorne. “It’s a face printing process like a print station, but it requires 500 to 700 pounds of pressure to hold the foil in place. If there are caliper variations in the substrate you want to be able to squeeze those out. To get good speeds requires a harder impression roller surface. If there are variations in anything, the result will have voids. Consequently, it takes a fair amount of pressure into a hard roller to eat those variations up.”

Most foil stamping cylinders are heated electrically. A shaft runs through the cylinder and contains a heat element. An infrared sensor reads the outside temperature of the cylinder so that the operator knows when the proper degree of heat has been reached.

According to Kuschnitzky, brass is the top of the line for stamping die cylinders. “People have tried to make them out of other metals. Brass, at the end of the day, is the best for engraving. It gives the clearest and cleanest images.” Flat stamping dies, he adds, can also be made of magnesium (low-end) and copper.

Market-wise, the rotary hot foil stamping market has felt economic pressures over the past year. “2000 was a better year for equipment,” says Kuschnitzky. “People tend to be a bit more careful these days. If someone requests foil now, they converter will order equipment only if the job is in the house.”

“Hot foil has tapered off a bit,” notes Kirtz. “We haven’t seen a lot of activity in the past few months, but there are inquiries. Some jobs are changing hands, and we have benefited by that. The new label printer might not have all the ancillary equipment to do the work, so we’ve been quoting on machinery for those jobs.”

Hot foil application, say Kirtz and others, is still the premiere method. “If you’re doing cosmetic products, or other upper-high-end products with a lot of detail, hot foil is still the answer.”

It used to be that hot foil was the only method of application, but there’s a new kid on the block.

Cold foil transfer
Quite a few foil manufacturers have come up with ways to apply foil without the hot process. They work with adhesive manufacturers and in some cases have spent years in R&D. Most of these systems require a UV curable adhesive.

Here’s how it works. Using a conventional print station on a flexo press, the adhesive is transferred to a photopolymer plate by an anilox roll. The plate transfers the adhesive, in the desired pattern, to the substrate. The substrate is then exposed to UV light to bring it to the right level of adhesion, or tack. Foil is then applied to the substrate, nipped at a specific pressure, then removed via a rewind.

Some in the industry say it is wise to varnish or apply an overlaminating film to protect the foil. Others say it’s not always necessary.

“There have been great improvements in the past six months in the cold foil process,” says Kirtz, whose company recently introduced an equipment package for the process that is designed to fit into any press. “It’s not as crisp and clean as the work produced by hot foil. You can still see some ragged edges and some filling in. You can tell a difference, but you have to know what you’re looking for.”

Driscoll Label Co., in Fairfield, NJ, is no stranger to the cold foil process. President Bob Biava developed a proprietary process more than 10 years ago, which he markets as StarBrite. The technology has been licensed to a select group of converters over the years.

“The difference between my process and those being developed today is that mine uses a water based adhesive,” Biava says. “I don’t need a UV station. I can put my foil down anywhere along the line, and print over it if I have to. With most of the new systems you need two stations with UV, the first one to cure the adhesive and the second one to varnish the finished product. Foil is above the surface of the label, so if you don’t put a varnish on it, or an overlaminate, it can be scuffed in shipping.”

In the StarBrite process the adhesive is dried with hot air before the foil is applied, creating the proper tack. “That tack is what pulls the foil from the carrier film. Once you pull that off, you’re done.”

API Foils, working with Akzo Nobel Inks, Telstar, and I.Kela, has developed a substrate that takes the cold foil process a step further. The process is called ThruCure, and the basic difference is this: The adhesive is UV-cured right through the foil.

According to Steve Oswald, product manager, dieless foiling at API, ThruCure involves a “wet lamination” process. The adhesive is applied by the photopolymer plate to the substrate, and the foil is nipped to it immediately thereafter. It is at that point that the substrate — foil and all — passes through the ultraviolet light for curing.

“The adhesive is made from relatively low energy materials,” Oswald says, “and does not require much energy to cure.” The adhesive contains free radical chemistry, he adds, and will cure instantly. The “dry lamination” process, in which the foil is applied after the UV cure, utilizes a cationic chemistry, which contributes an unpredictability factor to the curing process. The aim in developing the new process was to avoid the variables associated with the dry lamination process.

“The foil is specially manufactured to allow enough of the UV spectrum to penetrate,” he says, “so the adhesive gets enough energy to cure.” Oswald notes that the company is careful in describing the foil as translucent, because of the connotation. “If you think of translucency in foil, which is normally opaque, you might shy away from it. It really takes a super-trained eye to see the difference between the opacity and reflectivity of a hot stamped image vs. one produced by cold ThruCure. In the finished product, it is almost impossible to discern a difference.

“We have run tests with close to 60 label converters in the past five to six months,” Oswald says. “Most have been successful. You can count on one hand those that were not, and their failures were easily explained.”

The waste factor
Foil is expensive, relatively speaking, and one of the aspects of its use that makes some converters unhappy is the waste. Foil traditionally does not cover large areas of the label or package, and therefore much of the foil remains on the roll and ends up in the rewind. It is not recyclable, at least not into first-grade material.

One way that foil can be conserved is by using more of it in the application process. Companies such as Total Register, Brookfield, CT, have developed systems that will reposition the foil during the stamping process to make use of the unstamped portions. Total Register’s process, called Foilsaver, is a shuttle-controlled system that regulates the speed of the foil through the stamping unit, causing it to pause and back up so that the next impression is adjacent to the first.

Gallus’ new foil application system can conserve foil by
utilizing narrow rolls (left), which are stamped by engraved brass rings on an electrically heated mandrel (right).

Gallus, the Switzerland-based press manufacturer, introduced a foil saving concept at Labelexpo Europe last year on its EM 280 flexo press. Foil can be mounted on the unwinds above the substrate in narrow ribbons. Instead of heavy electrically heated engraved cylinders, the images are stamped by engravings on brass rings that are mounted on an electrically heated mandrel.

“You can use three strains of foil,” says Harold Jacob, product manager at Gallus Inc., based in Philadelphia. “You can use it only for the width of the image that you need, with no waste of foil between. The advantages of the rings themselves is that instead of a full cylinder, you buy only the width you need.”

The unit, which contains unwinds, rewinds, and the appliation equipment between, is modular, and can replace any print station on the press.