by Jeff Peterson, Foil & Specialty Effects Association
As technology and processes have changed in the printing industry, hot stamping foil manufacturers have had to change, as well. Today, foils must be compatible with digitally printed materials, a new array of specialty UV coatings, UV inks and an ever-growing choice of substrates in the marketplace. In addition, finishers who offer foil stamping need to run presses at faster and faster speeds, with high demand from customers not going away anytime soon. Foil manufacturers have formulations for both narrow web and sheet-fed cold foil applications, too, which continue to grow in popularity.
Foil improves to meet demand for press speed and substrate variance In years past, it was difficult for the print finisher offering foil stamping services to keep in inventory a type of foil that could work on a variety of stocks. “In the past, there were many formulations of foil for all types of substrates and coatings,” remarked Paul Miller, technical support manager for API Foils. “These days, we have products that can work on a broader range of substrates. This has helped foil stampers with faster turnaround times and saved them from having to place special orders for every foil job.”
With the increased use of foil in high-speed narrow web applications over the last several years, foil manufacturers have had to adjust their formulations to result in quicker releases and much faster run speeds. These improvements have spilled over into the sheet-fed side to help both platen and clamshell foil presses run at faster speeds and at lower foil release temperatures. “The growth in the use of both hot and cold foils in rotary narrow web applications has seen foil manufacturers develop foils that perform at higher rates of speed and still offer the same performance in coverage, fine-line detail, high-sheen and sharp edge definition,” stated Brian Hill, technical specialist, Kurz Transfer Products. “In addition, new foil formulations have been developed to run at lower temperatures and still maintain excellent coverage through the press run.”
Growth of digital printing adds foil challenges
The world of digital printing is growing at an astronomical rate. Studies show that digital printing will grow nearly 10 percent each year over the next five to ten years, while other printing processes will continue a gradual decline. The technology is allowing faster speeds and larger sheets, meaning more digitally printed work is showing up on the doorsteps of the print finisher every day. “We now are seeing a substantial and growing percentage of the jobs coming in have been digitally printed,” said Bob Windler, president of Diecrafters, a Cicero, Illinois, print finisher. “It is more important than ever that we have foil products and set procedures to work with digitally printed materials.”
Foil manufacturers have created specific formulations that have been shown to work very well on many of the inkjet and toner-based digital machines. It is recommended to have these products readily available on the shelf – especially in gold and silver. This can help increase margins, since special orders won’t need to be placed, and decrease turnaround times, which are usually very short on short-run digital work. In addition, keeping a general foil on hand that works with digitally printed material should not take up an enormous amount of inventory space since many times the digitally printed jobs are smaller in nature. However, as stated earlier, the volume of digitally printed materials continues to grow as the technology changes.
Foils adapt to work with coatings
In recent years, the use of specialty coatings and laminates has been on the increase. This includes textured, profile (raised) and soft touch coatings, as well as soft touch and other specialty laminates. “Foil products have improved in the way they work on certain UV coatings,” says Ken Noonan, technical service representative for ITW Foils. “However, specialty coatings, such as soft touch, have been somewhat unpredictable. Sometimes, they foil stamp fine and other jobs are very difficult.” As with any questionable coatings or inks, it is best to have samples completed and foil stamped ahead of time to determine if the foil will be compatible with the coating.
One of the largest problems with certain coatings and laminates in the past has been a low dyne count (or high surface tension) on the surface of the substrate. Special foil formulations now are available that can stamp on dyne levels as low as 30 dynes; while just ten years ago or less, surfaces had to be nearly 40 dynes before they were stampable. Most of these special foils are available in gold and silver only, but have proved to work very well on UV coatings and laminates that at one point were virtually impossible to foil stamp.
Many UV coatings now are added inline with the printing press. “The inline coatings seem to cause fewer problems with foil adhesion, as long as they have been cured effectively, than with offline coatings,” remarked Hill. “The inline use of the coatings usually is at a lower volume and helps create less chance for very low dyne counts on the substrate.”
“Ideally, it still is best to add the UV coating after the foil is applied,” stated Miller, which he recommends to customers whenever possible. “It is very difficult to tell if a foil is applied before or after the coating when looking at it from even a short distance,” continued Miller. “Coating after the foil stamping also protects the foil, as it does the inks.”
Cold foil meets a newer industry need
The growth in the use of cold foil for both narrow web flexo and sheet-fed applications has forced foil manufacturers to create special formulations that release from the contact of a tacky adhesive rather than the heat and pressure of a foil stamping press. This increase in cold foil popularity adds to the special formulations that now must be available in the marketplace. “Cold foil certainly is here to stay for certain applications,” explained Noonan. “The foil products now available for cold foil are much better today than just a few years ago, including quality adhesives and the proper printing blankets to match the foiling.”
It is important to point out that using a quality adhesive is just as important as the foil for the cold foil process. The foils, adhesives and process for applying cold foil all have improved in recent years to create a higher quality finished product. However, hot foil stamping still is preferred for many foil applications and can be a better solution, depending on the overall coverage needs and specific application.
Hot and cold foils will evolve as the graphic arts industry continues to change. These changes include the growth of digital (inkjet) printing, an increased use of specialty coatings and laminates and the increase in cold foil usage. All of this is keeping the chemists within the foil manufacturing companies very busy and adds to the challenges of job production for print finishers. “I have been in this business for over 40 years,” said Windler. “It amazes me that we continue to run into new foil challenges and opportunities on an almost weekly basis.”