With more advances from digital and hybrid presses, innovations from overlaminate suppliers are also increasing. In fact, the next few years are expected to be an even greater period of growth for overlaminates, as factors such an environmental concerns and ink system improvement will help to drive their use.
Here, Tom DuPont, corporate R&D director at acpo Ltd, discusses with FLEXO Magazine the role overlaminates play, their benefits, future outlook of the market and more.
FLEXO Magazine: What role does an overlamination film play in the construction of a pressure-sensitive (PS) label? What are the benefits overlaminate materials provide?
Tom DuPont: Overlaminates are often the last thought of part of a PS label. However, they can have a positive or negative affect on the appearance and performance of the overall label. The overlaminate not only protects and enhances the label graphics, it is also functional. For example, there are heat-sealable, UV screening, low COF for high-speed fill lines, variable data printable and overlaminates used as open/close mechanisms in extended content labels (ECL). Not giving consideration to what you’re putting on the label may cause end-use failure, rejection or non-compliance.
FLEXO: What has changed in the overlaminate market in the last five to 10 years, and what can printers expect to change in the next five to 10 years?
DuPont: The biggest change in the past five or 10 years has been the commoditization of overlaminates. The North American market has been flooded with imported commodity products, which has driven prices down with no cost relief. Expectations are that prices should continue to drop each year since this has been the trend.
Another change is with the sophistication of printers. Concurrent with the commoditization of overlaminates has been the increased performance demand from innovative printers and end users. Innovation from printers with designs, materials, inks, etc. should drive innovations from overlaminate suppliers. The rate of innovation has increased with the advent of digital and hybrid presses. Overlaminate innovation should keep pace with—or in some cases even drive—some of these innovations. Customer regulatory requirements have also changed in the past five to 10 years. The overlaminate is no longer just a tag-along piece, but must meet requirements imposed on the rest of the product from toys to foods. Customer quality management systems have also improved, with expectations passed on to suppliers.
The past five to 10 years for overlaminates can be summed up as: prices decreasing, costs increasing or staying neutral, regulatory requirement increases and application sophistication increases.
The next five to 10 years will be exciting for overlaminations. Self-wound but printable products will grow as variable print designs become more the norm with digital printing. The goal of “to protect and enhance” will focus more on enhancement as the overlamination becomes part of the label design instead of simply a covering. Growth in ink systems will create a need for better adhesives. More emphasis will be placed on environmental concerns as the package and label will be asked to contribute to waste reduction initiatives by end users.
FLEXO: In what markets are overlamination films mostly used? What makes certain markets a good fit for using these materials? Are there any overlamination markets or areas of usage growing in particular?
DuPont: Overlaminate films are used in a wide range of markets—everywhere from health and beauty to industrial, pharmaceutical, pet food and even aeronautics. The ease of use and consistency of self-wound overlaminates over UV varnishes or press-applied films greatly benefits the label converter by helping to ensure the first label looks like the last. It also frees up a print station and reduces non-productive time spent dialing in the varnish or adhesive and cleanup.
One area of exceptional growth we’re seeing is in the flexible packaging market. Not surprisingly, digital printing technology continues to expand in the label and flexible packaging market. With this, the demand is growing for a wide range of robust, self-wound overlaminates designed to work specifically with these printers and finishers. Digital printing has evolved beyond short runs and personalization—High-end graphic capabilities, flexibility and low-cost setup have elevated it to assist brand owners to expand and achieve more customized marketing strategies.
FLEXO: How do overlaminates work with digital printing?
DuPont: Digital printing has brought about different surfaces because of the ink systems used. Some inks are tightly cross-linked, providing a lower surface energy to the overlaminate adhesive. Others have a little bit of outgassing of the carrier solvents to overcome. The choice of adhesive on the overlaminate is important to grow with the ink systems. Digital printing also brings an opportunity for variable printing on top of the overlaminate. The current state of self-wound overlaminates are designed to have a surface that releases the adhesive, which might not be compatible with printing. For some, digital print systems surface modifications are required to unwind and accept the respective ink systems.
FLEXO: What are some overlamination materials popular among customers?
DuPont: BOPP overlaminates are the most popular for indoor label applications including extended content, food and beverage, and household goods. These films provide scuff resistance and additional overall stability to the label at an attractive price point.
For more demanding or outdoor applications, we recommend PET overlaminates. PET films provide higher fade and heat resistance and overall durability than BOPPs, making them ideal for industrial equipment labels and any application requiring UL compliance.
FLEXO: What do overlaminates bring to the table when it comes to anti-counterfeiting measures?
DuPont: Anti-counterfeiting overlaminates bring an extra measure of security in a couple of ways. First, the press operator is not called upon to incorporate an anti-counterfeit measure into an ink or other coating. The original process of printing and then applying the overlaminate remain the same. Second, the security measure from the overlaminate could be transparent to the operator and most people in the building, so only a few people know security measures are being incorporated into the label design. In the world of counterfeiting, the fewer people who know about a security system, the lower the chance the measure is found and copied by a counterfeiter. Anti-counterfeiting measures in an overlaminate take one concern away from the press operator when processing labels important enough to include this protection.
FLEXO: What should printers be mindful of specifically when working with overlaminates?
DuPont: Printers should be most mindful of the critical interface between the ink and the overlaminate adhesive. The PS adhesives of overlaminates are viscoelastic and will flow. The extent of flow, which also relates to the bond strength, depends on the surface. An ink loaded with wax for a high-gloss appearance, for instance, could potentially keep the adhesive from properly flowing and creating a good bond. Some printers will flood coat with a primer to ensure the bond is solid.
Another key factor of this critical interface between the overlaminate and the ink is the amount of retained moisture in the ink before lamination. Most overlaminates are made with water-based acrylic adhesives. Even after drying, the surfactants in the adhesives from polymerization and coating formulation do not volatilize and are still present in the polymer entanglement of the adhesive. If the inks are not completely dried, any moisture in the inks could outgas and be drawn to the surfactant in the adhesive. One result could be what is commonly referred to as fish-eyes that do not “wet out.” Another result could be low adhesion since the adhesive is being asked to bond to a semi-liquid substance.
Another consideration is the end use of the label construction. As I mentioned, PET films offer better UV protection than BOPP films and so if a label is for use outdoors, a PET film should be used. In some cases, a specially designed, enhanced UV protection film is needed based on application. It is prudent to have the label system tested to check fade over time, such as 30 days in a UV unit (which relates to one-year exposure).
Finally, the overlaminate becomes part of the entire label construction and should be considered as part of the label design and not just an ancillary piece. Matching the modulus of the overlaminate to the label stock will aid processing and help reduce the possibility of curl. Having enough adhesive to account for the thickness of applied inks is also important, as cost reduction goals are driving lower coating weights. Print surface topography can vary as much as 3-µ., which means the adhesive must have enough mass to flow. It is prudent to work with your overlaminate supplier to get the best possible product for your application.
FLEXO: Are there any new products recently launched, or anything in the pipeline?
DuPont: In the flexible packaging market, acpo introduced several years ago its first flexible packaging overlaminate, a 48-gauge PET. We’ve since added heat-sealable films and are launching BarrierFlex with O2x Bloc technology, a line of printable films featuring a high oxygen barrier coating that is highly durable and flex crack resistant. This product line boasts no EVOH or chlorine. acpo also manufactures several self-wound overlaminates coated with our proprietary tackified adhesive developed specifically for digital printers.
In terms of new products, 2016 was an exciting year for acpo and 2017 [brought] even more offerings. Among the new products we’re manufacturing are anti-counterfeit, high-barrier flexible packaging film products and Sofsens, overlaminates with a soft feel.
acpo has developed multiple self-wound overlaminate products with embedded security features and the options of hidden customized messages, visual and audible authentication or layered technologies.
We have also partnered with Sun Chemical to provide SunBar coated films to flexible packaging converters. These clear films give converters a cost-effective alternative to multi-layer and PVdC-coated barrier films while providing ultra-high oxygen barrier properties, flex crack resistance and thermal resistance to support high-speed filling on packaging lines and pouch converting equipment. Excellent print reception will eliminate the need for a third layer, which supports package lightweighting, economics and efficiency.
And, acpo’s Sofsens films can be utilized on both labels and flexible packaging where a high-end, luxury look and feel is desired. The soft tactile sensation and matte finish will set the end product apart from others.
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