By Cassandra Balentine
Vinyl is a common substrate used by wide format digital print service providers (PSPs). A range of solutions with various attributes make each product well suited to different applications. Printable vinyl options include cast or calendared, as well as some specialty solutions.
One of the most popular elements vinyl media is made from is polyvinyl chloride (PVC), which is a synthetic plastic polymer. Non-PVC options are also available. Other materials found in the chemical makeup of vinyl products include polyethylene, polyolefin, and polypropylene.
Above: Avery Dennison offers vinyl media for wrapping vehicles.
Vinyl media selection is best determined based on application. For example, Adrian Cook, product manager, digital print films, 3M Commercial Solutions, points out that for vehicle wraps, installation features are critical because it’s a labor-intensive application. “Installers want a film that they can install quickly and correctly the first time. Problems such as lifting or bubbles can create rework that eat into a project’s profit margin. Durability is also important since the customer’s brand is on full display and any premature fading or cracking will cause dissatisfaction and potentially a costly rewrap.”
“For shorter term applications, cost and eco-friendliness often become larger factors since the media will only be used briefly before being discarded. The one attribute that is consistent across all applications is quality. Print providers want to provide a quality product for their customer, and that starts with using a quality media that’s appropriate for the application,” he shares.
Paul Roba, marketing manager, Avery Dennison Graphics Solutions, adds that PSPs have historically considered image quality a primary driver in media selection. “Other desirable attributes include durability, finish, lead time, specialty adhesives, and other factors depending on the end use.”
To meet these demands, a variety of vinyl products are on the market. Two of the most distinct types within the graphics market are cast and calendared.
“Cast film provides superior flexibility, durability, and conformability and can be used in three- and four-dimensional applications. Calendared films are cost-effective alternatives for applications that typically require one- or two-dimensional performance,” shares Roba.
Cook adds that cast films are typically more expensive and are better suited for more demanding applications where conformability, dimensional stability—resistance to shrinkage, or longer durability are required. “Examples of when you would want to use a cast film are vehicle wraps, textured wall graphics, and indoor graphics that cover entire walls,” he says.
On the other hand, calendared films are typically less expensive, thicker, and better suited for applications such as general signage, floor graphics, indoor wall graphics, and partial vehicle graphics and decals.
Roba says additional advantages of cast film include easy color matching and short production runs, while the primary disadvantage is the cost. Meanwhile, calendared films provide abrasion resistance and easy handling because of their thickness. Newer formulations allow them to be more conformable. The primary disadvantage is the minimum production run size. “However, over the years that has become more manageable as suppliers continue to improve their manufacturing processes,” he shares.
Further, the chemical makeup of each product is a consideration. For example, many vinyls are PVC. “PVC is a popular choice due to its print performance, versatility, and cost. PVC films can be cast or calendared and are formulated to create a variety of graphic films for different applications,” says Cook. Additionally, PVC-based products for applications range from vehicle wraps, general signage, and window graphics to wall and floor graphics.
Cook says more recently, non-PVC products have entered the market, such as 3M Envision Print Wrap Film 480mC. Non-PVC products are considered a “greener” solution for a variety of reasons, and sometimes provide other benefits. For example, 3M Envision Print Wrap Film 480mC has excellent conformability and installation characteristics in extreme temperatures compared to PVC products. “When comparing any two films of different chemistries, there will be tradeoffs so it’s important to understand the differences and choose the right product for the application,” he explains.
Digging even deeper, we look at the types of plasticizers used in vinyl, examples include monomeric and polymeric.
Roba explains that monomeric films are made up of smaller molecules, which are less stable and more likely to migrate out of the product. Whereas, the longer chains used in polymeric films allow for greater stability and durability.
Cook adds that monomeric calendared films are typically the least expensive and lowest performing films. They have the least dimensional stability and therefore will shrink the most, which makes them unsuitable for some applications. “In some scenarios, the monomeric plasticizers can migrate from the film into the adhesive and onto the surface of the film, which may cause variations in film, adhesive, and print properties,” he offers.
Polymeric calendared films are typically more expensive, higher performing, and more dimensionally stable. Some polymeric films are marketed as high performance, but still feature different performance than a cast film. “The technical specifications for a product may not state what type of film it is, so if you’re interested in this information you may need to contact the manufacturer directly,” explains Cook.
Perhaps one of the biggest issues surrounding vinyl is its environmental reputation. To address environmental concerns, some vinyl manufacturers are moving to non-phthalate plasticizers and lower volatile organic compound alternatives.
Frank Loncar, product development engineer, 3M, explains that PVC has of an environmental impact than many competing materials. “In the U.S., the vinyl chloride monomer is made from two abundant raw materials, seawater and natural gas. Since PVC can be tailored to the end use with additives, the manufacture of the polymer is extremely efficient on a large scale with little waste due to changeover from one grade to another.”
“For high-performance PVC graphic films, non-phthalate plasticizers are chosen in order to meet the performance needs of the customers. With the wide breadth of non-phthalate plasticizers available, attaining a desired performance is not an obstacle to adoption, but rather for some users there is little environmental or health impact to using phthalates in their products,” continues Loncar.
Roba points out that phthalates, in and of themselves, are present in a variety of consumer and industrial products. “These components can help products be more flexible and can increase overall durability,” he shares.
He adds that a few suspect phthalates have been replaced by others, but the replacement process is challenging because of the specific performance characteristics that each phthalate provides. “Avery Dennison, similar to other companies, looks to reduce our environmental footprint through product design, manufacturing processes, and formulations to meet industry and government standards.”
In October 2019, Renolit announced that it switched all of its U.S. production of its signage and graphics market product range to a non-phthalate plasticizer, Pevalen, which produced by Perstorp. A high-performance polyolester plasticizer, Pevalen provides plasticizing efficiency and low volatility and migration properties. It offers a low carbon dioxide footprint and is produced using biogas energy.
“We believe this switch is well-timed both from an environmental and safety aspect. It takes our compliance beyond the tough existing safety regulations and responds to the increasing consumer demand for greater sustainability. In making this switch, we have gained a clear competitive advantage in this market,” shares Ralph Gut, business unit manager, Renolit, in a press release announcing the move to the new plasticizer.
The graphics industry is constantly affected by market trends, including media demands. Recent trends move toward the adoption of log/roll slitters by print providers used to convert media before and after production runs, rather than purchase pre-converted media.
Roba points out that roll slitters have been used for many years. “These were typically used to cut master rolls in smaller sizes, primarily based on job requirements. There has been an increased demand for finishing slitters or equipment for PSPs to more efficiently trim print output and prepare it for installation,” he shares. “However, I am not aware of adhesive-based material manufacturers selling untrimmed rolls, this is because untrimmed edges can cause premature delimitation and feeding issues with large format printers.”
“Some customers prefer to do in-house converting for added flexibility in their operations or to gain cost efficiencies,” agrees Cook. “This scenario simplifies the production for raw media manufacturers because it removes a converting step from the process. However, there are also many third-party converters that can slit media very cost effectively, which provides an alternative to print providers purchasing their own converting equipment,” he adds.
Vinyl is a versatile substrate used for a range of applications in the graphic arts. Depending on the application at hand, as well as the preferences of the PSP and end user, selecting the right vinyl product involves many factors, including its chemical makeup.
Feb2020, Digital Output