PRA June-July 2013 feature-Thermoforming

Thermoforming

Enhanced solutions for the packaging market The thermoforming process, a part of the US$22 billion global plastics machinery industry, has remained intact as its counterparts, injection moulding and extrusion, have fluctuated over the years. Gains are stemming from the versatility and cost efficiency of thermoforming, combined with a healthy outlook for the domineering packaging sector.

The Weight Watchers tray is lighter

Plastic usage dominated by packaging The growth of thermoformed products will be supported by resin, additive, process equipment and computer-aided engineering enhancements, resulting in greater customisation, sharper detail, higher performance and quality standards, and an expanding array of potential applications.

Meanwhile, US firm BCC Research says that the global market for thermoformed plastics is expected to increase from 3.1 million tonnes in 2012 to 3.8 million tonnes by 2017, a 4% compound annual growth rate (CAGR).

The packaging segment dominates the sector, accounting for 80% of the total volume consumed. This sector is expected to grow to 2.72 million tonnes by 2017, at a CAGR of 4%.

Thermoformed trays to push market sector US research firm Freedonia Group says demand for trays in meat, poultry and seafood packaging is expected to increase 3.9% a year to US$860 million in 2015. The growth will be driven by a change in product mix towards larger and more expensive foam and rigid trays as a result of the increase in the market share of case-ready meats and the increasing popularity of processed ready-tocook meat, poultry and seafood products.

Freedonia projects that demand for foam trays will progress at a slower pace than non-foam trays because of market maturity and intensified competition from non-foam trays. Tray advancements are expected to be restrained by competition from flexible packaging formats, such as pouches and bags. Meanwhile, manufacturers are also moving more to in-line thermoformed rigid or semi-rigid formed packaging. Nevertheless, foam trays will continue to be the backbone of the meat packaging sector, with further growth coming from case-ready applications.

Benefits of foam trays include low cost, impermeability to moisture (which delays spoilage and bacteria growth), design flexibility and improved cushioning. The foam’s insulation properties also safeguard products from freezer burn.

Many retailers prefer case-ready systems, including foam trays and film overwrapping, because these products give the impression of professional wrapping, Freedonia explains. At the same time, the case-ready format removes labour costs associated with in-store meat cutting and packaging and it permits retailers to place meat in display cases as needed, which decreases losses due to spoilage.

The foam tray demand will also be reinforced by speciality trays, such as barrier foam trays for case-ready meats. Already on the market are trays that provide increased oxygen and moisture barrier properties, trays designed to absorb blood and other liquids, and pre-padded foam trays with a foam pad glued to the inside of the base.

Sustainability in packaging Sustainable packaging trends are also expected to impact foam tray demand, especially conventional foam PS trays, since some cities around the world are already banning their use, Freedonia says.

34

JUNE / JULY 2013

Thermoforming Other trends are to reduce gas emissions in the process with a focus on making trays less brittle, reducing waste due to breaks during production and eliminating one of the top consumer complaints of broken trays.

By replacing traditional CPET microwaveable trays with a hybrid material combining PP with calcium carbonate, US firm Pactiv Foodservice-Food Packaging reduced greenhouse gas emissions by 45% during processing. The new Weight Watchers frozen-food entrée tray, which was awarded a DuPont Award for Packaging Innovation last year, reduces weight by more than 15% and plastic use by more than 40%, compared with previous designs.

CPET tray and cold party cup achieve sustainability through lighter weights

In reuse of material, US-based MicroGREEN Polymers, which was founded by graduate researchers at the University of Washington and funded by angel investors and the Washington Research Foundation in 2006, has introduced a patented Ad-air solid-state microcellular process that uses non-reacting, recycled carbon dioxide gas to thermoform recycled PET rolls into trays and cups.

The production process makes the PET 45% lighter, without using chemical blowing agents, and because the plastic is not chemically altered, it can be recycled at the end of its life.

The firm also won the DuPont Award for its CPET trays and cold party cups, which are respectively 70% and 60% less dense, resulting in lower thermal conductivity. This allows consumers to handle CPET trays straight from the oven without being burnt and keeps the beverage in the cups cold, while providing environmental benefits.

Meanwhile, Germany-based BASF has introduced a compostable Ecovio T2308 grade for thermoforming trays and cups. The plastic exhibits similar mechanical properties to those of amorphous PET, but differs by virtue of its compostability and its high content of PLA. The content of Ecoflex, which is BASF’s compostable polyester, allows for a material that is not too stiff or brittle, allow for less damage to products during transportation and storage.

The Ecoflex component also ensures a balanced stiffnessto-strength ratio and BASF’s new Ecovio sufficient low-temperature grade is translucent impact strength.

Furthermore, the processing window for Ecovio T, between 80°C and 120°C, is broad in comparison to other plastics. Processing can be carried out on conventional flat-film installations and at speeds that are typical for thermoforming. Like all Ecovio grades, it also complies with food-contact stipulations. The material is translucent and can be adequately sealed with cover films.

PET, new benchmark in optical clarity Meanwhile, food industry research group Technomic says that retail food purchase grows at the peak of the economic slowdown and dwindles as economies recover.

This shift in purchase behaviour means that food retailers need to pit against choice criteria such as taste, quality, freshness and appearance of prepared foods – the latter being a key differentiator for a product to stand out, and in which clear packaging comes in handy.

As a result, thermoformers are said to be switching to PET sheet, which has the advantage of optical clarity.

Enhancing further the process to produce a PET packaging, Omanheadquartered Octal produces PET sheet directly from PET resin melt in a process known as DPET, resulting in a final product with enhanced optical and mechanical properties. The Octal says its DPET produces higher clarity in firm says its process provides the PET sheet increased gloss, no visual inclusions, finished parts without colour variations, with a high intrinsic viscosity and toughness. It also requires up to 5°C less heat at standard draw ratios in the thermoforming process, which means less energy consumption and more savings for the customer.

In terms of sustainability, DPET renders a carbon footprint said to be 25% below that of traditionally produced APET films.

Another improvement to aesthetics comes from French PP maker Polychim Industrie, a sister company of US-based Pinnacle Polymers. It has introduced the HA31XTF thermoforming PP grade that draws on the benefits of US firm Milliken Chemical’s nucleating additive Hyperform HPN-600ei to overcome the performance trade-offs associated with conventional nucleated PP homopolymers in thermoforming applications.

Hyperform is said to stimulate improved transparency and reduced yellowing. Other benefits are favourable stiffness/impact balance and isotropic shrinkage behaviour that avoids warpage. It also gives the possibility for thermoformers to improve productivity by up to 10% and reduce costs. The grade is aimed at clear PP and opaque thermoformed food packaging.

Polychim’s new thermoforming grade allows for improved aesthetics JUNE / JULY 2013

35