The benefits of thermoformed packaging are well documented: material cost-savings, high throughput, and ease of automation of downstream operations like trimming and stacking.
Competing with some injection molded goods, thermoformed packaging is increasingly being recognized as a means of replacing glass, metal, and paper packaging. Bernhard Rost, a spokesman at thermoforming machine builder Illig, Heilbronn, Germany, notes that the transition from other materials to thermoformed plastics has been long in the making, and cites examples such as meat trays (formerly made in coated cardboard) and yogurt cups (formerly all glass).
Reasons for the transition vary, but it is often cost, notes Scott Reinish, an engineer with Nobel Biocare, Gothenberg, Sweden, and Yorba Linda, CA. Reinish recently oversaw the transition from an opaque titanium/glass package for the firm’s dental implant abutments and associated tooling, to a clear thermoformed copolyester package using materials from Eastman Chemical, Kingsport, TN.
The cost of the old package was $1.28 per unit. The new tray costs $0.04/unit and has a lid in medical-grade paper. The labor cost to insert the items into the packaging was slashed by 80%, due to a new package design as well as automation of the process. Nobel Biocare worked with product development firm Omnica Corp., Irvine, CA, to create the package. Other problems, such as glass breakage, are no longer issues. Users also like that they can see the dental-implant components through the clear plastic.
Nobel Biocare’s packages are produced by Prent Thermoforming, Janesville, WI, which has a Class 100,000 cleanroom. Prent uses Glidex coextruded sheet from processor Goex, also in Janesville. Glidex has an a-b-a structure. The middle layer is a glycol-modified PET from Eastman, and the outer layers are of a proprietary de-nesting material.
Reinish says Nobel Biocare considered injection molded packaging but went with thermoforming due to lower cost, as annual volume is only about 2 million units — not enough to justify the expense of injection molds.
One application in which thermofomed packaging has been steadily replacing paper packaging is ice cream containers. In this application, thermoforming faces stiff competition from injection molding, and many large packaging producers offer both processes. Generally, thermoforming is used rather than injection molding, for thinwalling the packaging to save material costs. Economics is the key and one reason that some ice cream makers swing from paper to plastics and back to paper depending on materials pricing. But the overall trend is towards plastics.
One European retail chain with its own ice cream brand, Lidl, has transitioned in the past two years from paper to thermoformed polystyrene tubs made by RPC Bebo Plastik, Bremervörde, Germany. Post-thermoforming application of labels enables the use of labels that are of higher quality than those employed in in-mold decoration of injection molded tubs, one major reason Lidl went with thermoformed containers.
In sectors such as medical, food, and electronics, packaging is critical to moisture control. Improvements in barrier films and sheet should help propel thermoformed packaging into new applications.
Wout Luyten, research and technical service manager at ethylene-vinyl alcohol (EVOH) copolymer supplier Eval Europe, Antwerp, Belgium, says its new, thermoformable grades feature improved thermal stability for multilayer sheet processing with high-melt-temperature materials such as polyamide and polyethylene terephthalate. The thermal stability of the new evoh grades is about 50% higher than that of its previous grades.
Michael Schumann, marketing technical specialist for Honeywell Specialty Films, Morris Township, NJ, says its new Aclam laminated structures are targeted at packaging thermoformers for healthcare and lighting products. Aclam is made from the firm’s Aclar fluoropolymer film that is treated and extrusion-coated with a layer of ethylene-acrylic acid. Schumann sees applications in pharmaceuticals, electroluminescent lamps, and other products that are often packaged in either aluminum foil/plastic blisters or paperboard containers.