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Issue 05/2015

  • Text
  • Bioplastics
  • Materials
  • Barrier
  • Packaging
  • Biobased
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  • Biodegradable
  • Renewable
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Barrier By: Warwick

Barrier By: Warwick Armstrong General Manager Business Development and Marketing Plantic Technologies Altona, Victoria, Australia Renewable material with superior barrier performance As part of the Kuraray group (headquartered in Chiyoda, Prefecture Tokio, Japan) the world leader in barrier materials, Plantic Technologies Ltd (Altona, Victoria, Australia) brings to the barrier technology family naturally sourced, environmentally beneficial bio-plastics. PLANTIC is a generation of packaging materials developed by Plantic Technologies. The products are certified by Vincotte as 3 star rated biobased materials corresponding to 60 % to 80 % renewably resourced materials. A unique high barrier material, Plantic combines a number of features and unique properties to deliver an outstanding packaging material for extending the shelf life of fresh products such as meat, chicken, fish & seafood, small goods, fresh pasta and cheese. The unique features of Plantic include: • High renewable content • Outstanding gas barrier performance • Excellent barrier to taint and odour • Sealable to most currently used top lidding • Enhanced hot tack and seal strength • Excellent surface gloss Independent studies have confirmed the exceptional barrier performance of this material by extending the shelf life of fresh meat products by 15 – 40 %. Used by some of the world’s leading processors and retailers Plantic has already substituted conventional barrier materials in fresh packaging applications globally. Plantic grades include high barrier rigid, semi rigid and flexible materials for applications such as form fill & seal packaging, barrier preformed trays, vacuum skin packaging, stand up pouches and easy peel pack packaging applications for fresh food packaging markets. The grades are a multilayer structure comprising a core layer of Plantic biopolymer – which is certified as biodegradable and compostable. The outer layers provide moisture protective skins, and these can be produced with bio-based or petrochemical plastics, including 100 % biobased polyethylene derived from sugar cane. Plantic is manufactured using state of the art laminating technology whereby thin layers of plastics, such as polyethylene, polypropylene or polyethylene terephthalate are coated to a core layer of renewably sourced, high barrier Plantic sheet. The Plantic core provides exceptional gas barrier, with the skin layers providing moisture/water vapour barrier properties to the structure. The barrier sheet can be thermoformed into trays using industry standard equipment, including automatic form, fill, seal machines. Plantic have won numerous awards for innovative technology including the 2005/6 DuPont Australia and New Zealand Performance Materials and Chairman’s Award and the bronze winner of the PCA Sustainable Packaging Design Award. The key ingredient in Plantic is a non-genetically modified corn starch. This unique and patented technology means that Plantic material is created with 50 % less energy than that of the similar petrochemical plastics and combined with the benefit of plant based raw materials impart reduced environmental impacts. What is Plantic? Plantic is unique as the world’s first truly renewable Ultra Barrier material. Plantic has extended the range of gas barrier materials to launch a new category of Ultra Barrier materials, materials with an Oxygen Transmission Rate (OTR) below 1.0 cm³/m 2 /day. The excellent barrier properties are unique to Plantic, and derived from a proprietary process which allows the natural occurring polymer in starch to be used as a packaging material. Starch is a naturally occurring polysaccharide used as an energy store in green plants. Larger amounts of starch are particularly found in cereal crops (such as corn, wheat and rice) and also tubers (such as potato and cassava). The polymer component of starch is comprised of a linear polymer known as amylose and a highly branched polymer amylopectin. The starch used in Plantic has a very high proportion of amylose (>70 %), which gives it similar processing and properties to Poly PET (polyethylene terephthalate). Exceptional Barrier Performance. Plantic offers exceptional barrier performance, superior to that available with conventional barrier resins, including PVDC, MXD6 and EVOH. Table 1 presents a comparison of the Oxygen Barrier performance of a number of conventional polymers with Plantic. Figure 1 shows the effect of changes in environmental Relative Humidity on the gas barrier properties of commercial barrier films. Similar to the other hydrophilic polymers shown here, Plantic film will absorb moisture from the external environment, which causes a decrease in the barrier performance. 40 bioplastics MAGAZINE [05/15] Vol. 10

Barrier The rate of moisture absorption in Plantic is controlled and limited due to the water resistance of the barrier skin materials. Independent tests have shown that the barrier performance remains below instrument detection limits (typically 0.05 cm³/m 2 /day) for more than 7 days. Figure 2 demonstrates this for a Plantic sample, equilibrated at 75 % RH, and then exposed to 90 % RH. After 8 days there is no measurable change in the OTR, which remains below the instrument detection limit. The barrier performance of Plantic is even better at lower temperatures, as shown in figure 3. There is a factor of 3 decrease in the OTR at 50 % RH as the temperature is reduced from 20 °C to 5 °C. This is an important factor in the extended shelf life of fresh meat and poultry stored under refrigerated conditions. PLANTIC eco Plastic extends the shelf life of fresh food. Plantic have conducted a number of external trials at certified, independent laboratories to determine the actual shelf life of fresh meat, such as mince, chicken and fish compared to conventional polypropylene (PP) barrier trays currently used in the market. The same top web was used for all samples in both Plantic and PP trays. The results also indicated that samples packed in Plantic trays maintained the original colour for both chicken and sausage meat for longer than those packed in conventional PP trays. Shelf life extension was based on a combination of factors, including Total Plate Count, Coliform, pH, odour and colour assessment according to NATA regulations. The chicken packed in Plantic trays demonstrated a 40 % increase in shelf life and sausage meat packed in eco Plastic trays demonstrated 15 % increase in shelf life. Both products maintained their originally packaged colour (less browning due to oxidation) for longer in eco Plastic trays than those packed in PP trays. 3·25µ/m 2·day·atm] OTR [cm Figure 1: Effect of relative humidity on oxygen transmission rate for a selection of commercial barrier polymers. OTR cm 3 /m 2 /day 100.0 10.0 1.0 0.1 0 0.05 0.04 0.03 0.02 0.01 0 -0.01 -0.02 0 EVOH-32 % EVOH-44 % MXD6 Plantic 20 40 60 80 100 % RH Specimen A, 0.46 mm Specimen B, 0.47 mm 1 2 3 4 5 6 7 8 Days after RH change Figure 2: Effect of a change in external relative humidity from 75 % to 90 % on the barrier performance of Plantic. (Test Method: ASTM F1927-98: 23 °C (± 0.2 °C), RH as specified ± 3 %, Test gas 100 % Oxygen) Table 1: Comparative barrier performance of packaging film materials. Material OTR cm³/m²/day 25 µm, 23 °C, 50 % RH WVTR g/m²/day 25 µm, 38 °C, 90 % RH LDPE 6,500 18 HDPE 2,300 6 PP 2,300 11 PLA 600 300 PVC 200 46 PET 40 20 Nylon 6 32 160 MXD6 2.0 80 PVDC 2.0 3 EVOH 44 % 1.0 20 EVOH 32 % 0.2 60 Plantic 0.5 150 Figure 3: Effect of temperature on the barrier performance of Plantic. OTR [cc·25µ/m 2·day·atm] 1 0.1 0.01 0 5 °C 10 °C 15 °C 20 °C 20 40 60 80 % RH bioplastics MAGAZINE [05/15] Vol. 10 41

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