Read Microsoft Word - HDPE Fact Sheet 15 April.doc text version

HDPE plastic packaging

Plastic is the most recently introduced of the major packaging types. Polyethylene was discovered by British chemists in 1933. High density polyethylene (HDPE) was first developed for packaging as a film before being introduced as a bottle for milk in 1964. Its use for packaging has increased because of its low cost, flexibility, durability, ability to withstand the sterilising process, and resistance to many chemicals. About half of HDPE consumed in NZ is used for packaging and about 60% of the packaging is for food contact purposes. As food packaging, HDPE is most commonly associated with milk, oil, and juice bottles. Non-food packaging uses include supermarket bags, cleaning product containers, motor oil containers, agricultural films and chemical containers, paper bag liners, bags, crates, drums, and pails. Different grades of HDPE are used for different purposes. For example, there is a blow mould grade (used for milk bottles, and detergent bottles) and an injection grade material (ice cream containers). Disadvantages of HDPE as a packaging material include its low resistance to UV light and gas permeability. New technologies, such as barrier coatings and multi-layer materials, are being introduced to improve these characteristics. HDPE is produced from ethylene (a simple hydrocarbon) in a low-pressure reactor containing a liquid hydrocarbon solvent in the presence of metallic catalysts (Ziegler catalysts). The resulting polymer produces slurry as it forms, which is filtered from the solvent. The material is then extruded into long strands which are cut to form solid pellets or granules. There are a range of processes used for manufacturing packaging from HDPE. Milk bottles, for instance, are blow-moulded on a continuous extrusion type machine. In comparison, larger containers, such as jerry cans and drums, are produced on an accumulator diehead type machine. HDPE packaging is capable of being recycled into new products. The majority of HDPE recycled in New Zealand comes from recovered bottles. Recovered HDPE containers require sorting into different grades. This is for the most part, in New Zealand, done manually on the basis of product types. Kerbside recycling collections are usually sorted into two grades of rigid HDPE ­ uncoloured milk bottle grade and coloured packaging, like cleaning product containers. The recycler commonly compacts recovered material into bales for transport to a reclaiming processor. The reclaimer shreds the material into flakes, which are washed, and the contaminants are removed in a flotation process. The dried flakes are re-granulated and become the raw material for manufacture into new products. Recovered plastic does lose some of its original properties due to contamination and slight changes in the molecular composition. Therefore, recycled HDPE packaging is usually used in products that require lower quality raw materials. In some cases, HDPE can be recycled back into the same product, but the addition of some virgin materials is required to achieve a quality result. Most HDPE recovered is from milk and other bottles and is reprocessed in New Zealand. Typical products made using recovered HDPE include drainage pipe, matting, slip-sheets, recycling bins, and buckets. The balance is exported, usually to Asian markets. Thermal

fusion processes can be used to produce a commingled plastic, which can be moulded into products such as cable covers, reels, crash barriers, and plastic lumber.

Statistics Plastics New Zealand estimates New Zealanders used over 21,000 tonnes of HDPE packaging in 2003, with 7,539 tonnes collected for recycling. These figures include HDPE consumed for containers and a smaller amount of film packaging. Pre-consumer recycling practices Recycling of plastic by manufacturers, where offcuts and production waste is reground and reused in the same or similar products, is common. It can be done either in-house or by outside contractors. Any remaining waste material is generally recovered by commercial recycling operators. Post-consumer recycling practices Councils provide kerbside and/or drop-off recycling facilities for recyclable packaging, generally including HDPE bottles, throughout New Zealand. Many councils do not collect HDPE packaging other than bottles. Recycling operators also collect bottles and other forms of HDPE waste, such as films, from commercial customers. Recyclers provide commingled recyclables collection services to some commercial customers. Barriers to recovery and recycling The bulkiness of plastic containers results in high recycling collection and transport costs. The "lightweighting" of HDPE containers results in recyclers recovering a smaller quantity of material after handling the same number of containers. To return the highest value to recyclers, HDPE must be of all one grade, one colour, and be almost entirely free of contamination. The expense of sorting material into different grades and colours can make its recovery uneconomic. Coloured HDPE, multi-layered package types, and packages with barrier coatings or containing barrier resins may not be readily marketable. Package components such as the cap, the label, and the colouring can reduce the value of the recovered material if not removed or designed with recycling in mind. Metallised labels, for instance, do not separate well from the flaked plastic, potentially making recovery of packages with these labels uneconomic. PVC shrink labels are very difficult to remove and most markets have a zero tolerance of PVC contamination. There is no widely-accepted definition of "recyclability" with regards to HDPE, so there is no consistency amongst councils as to what is collected. Opportunities for improvement of recovery and recycling Extended producer responsibility or take-back systems would increase the recovery rate of postconsumer packaging. HDPE containers represent 0.5% by weight of domestic refuse in areas with kerbside recycling. This represents in the order of 3,000 tonnes of HDPE containers per year nationwide. A proportion of HDPE bottles are used and disposed of in public areas and at public events. Public area and event recycling is not common in New Zealand. Recycling in the retail, tourism, and hospitality sectors needs further development. Increasing public awareness about recycling and contamination issues will result in improved HDPE recovery rates.

Recycling for post-consumer commercial packaging such as large containers and film is not available or easily accessed by all consumers. Markets for recovered material Approximately two thirds of the HDPE material recovered is used within New Zealand. remaining third is exported, primarily to Asian and Australian markets. Barriers to development of markets for recovered material In most of New Zealand, the small quantities that are collected do not justify the establishment of reprocessing or manufacturing operations. Regulations in some overseas jurisdictions restrict the import of post-consumer packaging by classifying it as a "waste" material. The low returns received by recyclers for mixed HDPE can make export uneconomic. Opportunities for market development The expansion of New Zealand processing capacity could improve markets, particularly for lowgrade post-consumer materials. The manufacture of products such as "plastic lumber" can use mixed, low-grade, and contaminated feedstock. Additives are being developed for improving the reprocessing capability of plastics. New processing technologies are being developed that can reclaim energy from recovered plastics. "Green" procurement policies will support the development of additional markets for recovered plastics. Further information and disclaimer This fact sheet, produced by the Recycling Operators of New Zealand (RONZ), provides general information only and is to be used as a quick guide, not as a complete resource on the subject. Published August 2004. For further information contact: The

Recycling Operators of New Zealand Inc (RONZ) [email protected] www.ronz.org.nz

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