Bottles By Kim Ji Hyun
Bottles By Kim Ji Hyun R&D center SK Chemicals Gyeonggi-Do, KOREA New Bottle Material A new bio-based, BPA-free and high-temperature copolyester SK Chemicals, the leading copolyester resin manufacturing company based in Korea, has recently developed ECOZEN ® , the world’s first eco-friendly high-temperature copolyester resin. The new Ecozen range of products is being produced at the SK Chemicals plant in Ulsan, Korea, in a proprietary process, alongside the existing SKYGREEN copolyester and SKYPET PET products. Ecozen provides an increased performance over existing copolyester materials in almost all areas, particularly temperature resistance and is seen by the manufacturer as a viable alternative to materials such as polycarbonate (PC). Other advantages over PC include the fact that Ecozen contains no Bisphenol-A (BPA), the ingredient of PC that has recently caused it to be banned for use in children’s products in many countries worldwide. In addition, Ecozen is the first copolyester in the world to be made using a bio-based monomer that is derived from renewable resources such as corn or wheat. The biomass contained in the currently available grades of Ecozen ranges from 9% up to 30%. Ecozen Properties Since they were first discovered, copolyesters have enjoyed rapid market acceptance and growth due to their combination of easy-processing and excellent properties. However, the relatively low maximum service temperature of copolyester has, until now, limited their use to low temperature applications up to about 70°C. This has made the material unsuitable for critical applications such as hot-filled and pasteurised containers, and dishwasher-proof reusable cookware and food-storage containers. Ecozen retains all the advantages of traditional copolyesters but now has the high HDT properties necessary to compete with materials such as PC or heat-set PET in temperature-resistant containers for hot-filled or pasteurised products, or for baby’s products that require sterilisation. (Fig. 1) 18 bioplastics MAGAZINE [04/11] Vol. 6
Bottles Ecozen is kinder to the environment since it is the first copolyester to contain a substantial content of renewable bio-based material, and it is also compatible with traditional copolyesters such as PET and PETG. This offers a whole new dimension compared to other competitive transparent plastic materials. For food storage and packaging applications, Ecozen offers excellent oxygen-barrier properties for long shelf-life food and beverage products. Table 1 shows typical oxygen permeation coefficients for polycarbonate (PC), polypropylene (PP), copolyester (PETG) and Ecozen. The oxygen permeation coefficient of Ecozen is about ten times lower than either PC or PP and it is therefore the ideal material to produce food storage jars and bottles to extend the storage-life of oxygen-sensitive items such as fruit juice or dairy products. In addition, Ecozen also provides the high chemical resistance required to package products such as cosmetics, and has an excellent resistance to food-staining, a main requirement for food-storage containers and cookware. Ecozen Processing. The many advantages of copolyesters include their versatility and ease of processing using standard injection moulding, injection- and extrusion-blow moulding, and sheet, film or profile extrusion equipment. Similarly, Ecozen can also be used in all the above processes, with only minor changes to process parameters and no changes to mould design. This means that new users of Ecozen will not have the cost or inconvenience of setting up new processing conditions, or having to invest in new equipment or mould modifications. 120 100 80 60 40 20 0 PET PETG HDT-B (°C) HDT 85°C HDT 100°C HDT 110°C ECOCEN Fig. 1. HDT-B of PET, PETG and Ecozen (ASTM D648, 0.455MPa) Material ASTM Unit Oxygen Polycarbonate (PC) 93 Polypropylene (PP) 98 D 3985 cm³∙mm/(m²∙day∙bar) PETG 10 Ecozen 8 Table 1. Typical oxygen permeation coefficients of PC, PP, PETG and Ecozen at 23°C Ecozen Applications The excellent high-clarity and gloss properties of Ecozen combined with ease of processing offer the improved design flexibility required by packaging designers for high-quality cutting-edge cosmetics and perfume containers. Ecozen has the high melt-strength necessary to manufacture large-volume containers with an integral handle made by the extrusion-blow moulding process. Ecozen represents an attractive alternative to PC, which contains BPA, regarded by many authorities as an endocrine disruptor. Ecozen not only offers a BPA-free alternative to PC that is both durable and dishwasher-safe, but it also encourages consumers to use refillable bottles for products such as sports beverages. In addition to packaging, Ecozen, with a heat distortion temperature (HDT-B) increase of between 10°C to 40°C higher than that of other existing copolyesters, is also already replacing more traditional materials such as PC in many highperformance engineering applications within the electrical, electronics, construction and automobile sectors because of it’s unique combination of excellent impact-strength, high chemicalresistance and outstanding transparency. http://skecozen.com bioplastics MAGAZINE [04/11] Vol. 6 19
