A panel discussion, featuring four experts, delved into the unique opportunities available with shrink sleeve technologies. Duncan Henshall, business director of labels at Taghleef Industries, Timothy Kneale, president of TOPAS Advanced Polymers, Raul Matos, vice president of Karlville Development, and Will Schretzman, vice president of packaging at Verst Group Logistics, took part in event, which was moderated by AWA president and CEO Corey Reardon.
Currently, North America only accounts for 12% of the global sleeve labeling demand. This drew mixed reactions from the panel, as the group explored globalization. “I was surprised that North American volume is only 12%,” said Schretzman. “In the early days of shrink, there weren’t a lot of materials coming from overseas. Today, it’s very commonplace. Go to any tradeshow and you see the same type of applicator. From a label cost perspective, getting it from overseas puts our industry in commodity mode.”
In regards to globalization, Karlville’s Matos believes that the Internet and modern technology has brought people from around the world closer than ever before. This makes service a critical part of any business.
When it comes to innovation, Henshall stated that large brands are often risk averse. “Adoption means growth,” he says. “Often selecting the customer and partner is a critical part of growth because they determine how quickly things are adopted. The biggest brands out there are often very risk averse. Sometimes it’s better to work with the second third or fourth brand that has powerful aspirations. More and more of the early adopters are the really small companies like family owned businesses.”
Many larger businesses do not want to tamper with a formula that has been successful for them in the past. Therefore, innovators should channel energy toward adopters of new technologies. “That’s something we’ve tried very hard to work on,” added Henshall.
AWA hosted two concurrent technical sessions, designed to analyze the specifications behind integral parts to the shrink sleeve market. Industry experts presented “Production of Shrink Sleeves: Technical Challenges” and “Panel Discussion: Film Technology Developments.”
Seamus Lafferty, president of Accraply, moderated the shrink sleeve “Technical Challenges” session, which focused on ink adhesion, prepress, and slitting. Philip Heyworth of Klockner Pentaplast and Tom Hammer of Flint Group Narrow Web detailed how problems with the ink and film could lead to adhesions issues.
In discussing ink, Heyworth noted that shrink sleeves often falter with product residue, ink bleed, wet looks, and ink cracking. In addition, flex cracking on fold lines could be a seaming issue, and it is often more noticeable on dark substrates.
According to Heyworth, surface energy and wettability are two key aspects of adhesion. Surface energy of film needs to be within 10 dynes/cm about surface tension for wettability. The energy often changes based on the material used (PVC, PET-G, etc.). There are several options to improve surface energy in regard to shrink materials: corona discharge, priming, etching with acid, plasma treatment, flame treatment.
Corona treatment involves a high voltage discharge that ionizes the air to form ozone. It hits the film and makes polymer chains more reactive, thus allowing the oxygen in the material to react to it.
Flint Group’s Hammer explored challenges as they relate to the substrate. There is a challenge to maintain the ability to shrink, as ink is cross-linked when drying/curing. Another challenge involves adhesion to a wide array of substrates without priming.
Ink suppliers will also often provide specific inks for shrink films. When it comes to water-based flexo inks, proper anilox selection is critical, as is high air velocity drying–users don’t want too much heat. In addition, pH maintenance is critical and a user must catalyze the inks if they’re going through the steam tunnel.
UV flexo printing is all about the cure. Proper anilox selection is critical, as well as proper press speeds for the lamps. Maintenance of UV lamps is critical, and chill roller temperatures are important as well. Curing and drying the ink properly results in right COF.
When it comes to digital printing, HP Indigo inks require a digital print primer to adhere to the film.
Accraply’s Ben Ritter looked at how prepress can ensure a successful shrink sleeve. Prepress targets graphics and text distortion, as well as aligning graphics in high contour areas. It is important to locate container specifications, and the software requires users to understand film specifications. Users can also utilize a 3D scanning unit for digital CAD files.
Prepress requires the need to understand chemical reactions. For example, how do you take a flat and convert it to tube? Horizontal graphic tolerance is critical, as a container must match for 360-degree coverage.
Sean Craig of Maxcess explored shear slitting for shrink sleeve films. According to Craig, the objective is to control the crack and focus the fracture. Poor edge quality is disastrous to the process, and razor sharp isn't necessarily good enough. The web has tension and dragging will affect slit quality.
A slitting solution involves tangent shear slitting of shrink sleeve films. This process avoids lateral stress, and the forces are perpendicular to the crack. Crack propagation is concentrated in a precise and focused location.
The following are critical factors to control in tangent shear slitting: Slitter geometry; overlap; overspeed; blade profile and sharpness; cant angle; and side force.
To illustrate how sleeve labeling can enhance a brand, the Karlville Development Group hosted a facility tour on Day 1 of the conference. Karlville provides equipment for shrink sleeves, flexible packaging and pouches. The company’s technical and innovation center allowed visitors of the AWA International Sleeve Label Conference & Exhibition to see these applications demonstrated live.
In addition to the Karlville-HP Indigo Pack Ready Laminator, the company displayed shrink sleeve converting, including everything from seaming and inspection to cutting and sample making. Shrink sleeves were also automatically applied and shrunk with dry steam.
Karlville also showcased the SP600, which is a high-speed applicator that can process roughly 600 containers per minute. It is suitable for use in flexible packaging, aiding in the beverage, pharmaceutical and cosmetics industries.