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Technology Focus

New Innovations with Film Laminating

by Jeff Peterson

February-March, 2002
Film lamination continues to be an area where graphic finishers are turning to offer expanded services to their customers. As a high value-added service with good profitability potentials, lamination offers considerable “impact” to a product and works well with other finishing processes, including foil stamping and die cutting. Lamination also provides a product the combination of high gloss, durability, and protection of the printed image. And now, with faster, more user-friendly equipment and new colorful film products, including holographic films, lamination is becoming increasingly popular for a variety of graphic arts applications.

Machinery Improvements

Two basic types of film lamination processes exist on the market – dry or wet laminating systems. The most widely used system in the sheet-fed market is dry or thermal lamination. Dry systems are easy to operate and require a lower capital investment. Wet systems, on the other hand, can run at higher production speeds and can save a substantial amount in film costs versus thermal films, especially in high volume applications. Although most systems for trade finishing applications in North America are thermal laminating systems, there is a trend in international markets towards wet systems. Improvements in adhesive systems in recent years, and the necessity for finishers to run equipment at faster and faster speeds, has made wet laminating systems a more interesting prospect. Wet laminating systems are designed to utilize raw films and coat the needed adhesive in-line with the laminating process, which is substantially less expensive than thermal films. With the use of wet laminating systems, the sheet-fed market is trying to utilize some of the advantages that web-based systems have used to increase speeds and decrease costs.

Improvements in film laminating machinery have created a larger market for film laminating as well. As with other sheet-fed printing and finishing machinery, material handling systems, such as better feeders, stackers, and pre-loaders, can create a much more efficient operation. Improvements with feeders and stackers help the laminator operator handle a variety of paper stocks in a more efficient manner. Utilizing pre-loader systems also can reduce downtime and feeder adjustments. Newer laminating systems have incorporated “press like” feeders into their machines. This has opened up many new opportunities. The inability to feed paper or board in a fast and efficient manner has always been an ‘Achilles heel’ of many laminating machines.

As with other printing and finishing processes, the cleanliness of the sheet can have a major impact on the quality of a job. Many laminating systems now include a sheet cleaner to help remove spray powder to ensure a smoother, faster-running job. In addition, newer systems have better drive systems, utilizing more servomotors. This helps feed and control the sheets more accurately. It also reduces waste of film and lowers potential problems in manufacturing.

Utilizing a laminating system with proper heat distribution and nip pressure control in the laminating calendars is also an important feature, especially for trade finishers, where increased flexibility is of utmost importance. Thermal films bond better if the adhesive on the film has been properly reactivated uniformly across the width of the film web. Pressure adjustability of the calendars allows the trade finisher to be more flexible with the type of films it uses as well as the different types of paper stocks it can run.

Since the film is in web form as it is laminated to each sheet, the film must be cut or sheeted as it passes through the press. New developments have been made such as the patented rotating hot knife from Steinemann, bursting rollers, and flying knives that have created stress-free cutting of the film. This helps reduce tension and curling problems sometimes associated with film laminated products.

Several laminating machines are now on the market running at speeds in excess of 200 feet per minute, which is considerably faster than the average film laminator now in operation in many shops. The faster a trade finisher can turn high quality jobs, the less likely its printing customer will consider bringing laminating in-house. If volume justifies it, it is also recommended to consider a specialized machine for particular applications. Flexibility is nice, but more flexible machines, many times, are not the most efficient.

Laminating Films

In addition to the improvements available today with laminating equipment, films have also become more user-friendly and flexible. One critical component with films, especially when other finishing processes like foil stamping, gluing, spot coating, etc. are going to be applied, is the surface treatment level. Films with a higher dyne level will, in most cases, perform much better with these other processes. Typically, a chemically treated film is desired because it will hold its dyne level for longer periods of time than a film that has been corona treated. Polyester (PET) naturally has a higher surface energy than Polypropylene (OPP) films. Because PET already has a higher surface tension level, enhancing it with a corona or chemical treatment makes it extremely user-friendly for other finishing processes after lamination. While PET films have been available in the marketplace for some time, they did not always have the dimensional characteristics that were optimum for thermal lamination. Recent innovations with PET films have improved the dimensional characteristics, making it an excellent choice for many thermal film applications.

When selecting a film for a particular application, it is important to understand what needs to be achieved. Laminating films can be made from several base materials that all have specific attributes. OPP, for example, is typically lower in cost, but is a softer film that is easier to scratch or scuff. PET films are a little more expensive, but have better scuff resistance. It is suggested to contact a thermal film manufacturer and explain the application so the proper film can be selected for the particular application.

Gloss and protection are not the only applications for clear film, as in recent years, the decorative use of laminating films has significantly increased. Today, many applications exist that combine several unique processes to enhance its appearance. A sheet laminated with a clear gloss film may incorporate a matte spot UV to draw attention to a particular printed graphic. That same sheet also may have an area that is foil stamped and embossed.

The use of metalized films is increasing as well. In many cases, the sheet is laminated with the metalized film and then printed over the top with a 4-color process, much like overprinting hot stamping foil. Different varieties of metalized films are also now available, including brushed metals, super bright surfaces that mirror chrome, and even products that mimic a galvanized appearance. Holographic films for laminating have also continued to gain popularity. As with other holographic products, the cost has decreased enough in recent years to make it a feasible option for many applications. Holographic laminating films are available in both translucent and metalized versions and come in many standard patterns, much like holographic hot stamping foils.

In the past, difficult surfaces or applications that involved weatherability or UV protection had to utilize pressure sensitive films to complete the job. Improvements in thermal laminating films and the specialization of the adhesive layers have expanded the use of thermal films into applications never before thought possible. Lower melt adhesive layers with more aggressive bonding characteristics are now available, as well as films with UV inhibitors.

With improvements in adhesive layers and adhesion capabilities, along with the expanded market for decorative films, new opportunities continue to surface on a daily basis. Couple this with continued improvements with laminating machine capabilities, and film lamination continues to be a strong potential growth area for graphic finishing operations as well as for other market segments.

InsideFinishing would like to thank Claude Schmid of Schmid Corporation (864-595-0087) and Bill Gaspelin of Protect-all (262-724-3292) for their assistance with this article. This article was based on the presentation on film laminating by Claude Schmid and Bill Gaspelin that took place at the recent FSEA 6th Annual Convention.