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你现在的位置：夜深人未静>学习笔记>论文资料(二)常用塑料的环境标签,塑料容器、包装和胶卷的处理问题
论文资料(二)常用塑料的环境标签,塑料容器、包装和胶卷的处理问题 [728,2005]
www.recycle.mcmail.com/label.htm (标签)
PLASTICS SYMBOLS
To recycle the different types of post-use plastics, they must be identified. The six types most commonly used in packaging usually carry the following symbols.
PET
Polyethylene terephthalate
LDPE
Low density polyethylene
HDPE
High density polyethylene
PP
Polypropylene
PVC
Polyvinyl chloride
PS
Polystyrene
There is a seventh, which covers "all other resins". About 50% of UK post-use plastic is PE (labelled 1,2 and 4), and 20% PP. It is to be noted that PVC carries the greatest health risks, and its use is being increasingly restricted throughout Europe in sensitive areas such as food and drink packaging and babies' dummies. It also contributes highly toxic dioxins to the air when incinerated.
The Green Claims Code is a DETR initiative which lays down a list of dos and don’ts for manufacturers who want to market their products to green consumers. For example, the code says that green claims should be written in plain language, capable of being supported by scientific evidence which can be independently verified and explicit about the meaning of any symbol used in the claim. The Green Claims Code is designed to serve as an interim measure while the Government looks at the legislation concerning labelling. Copies are available from DETR Publications Despatch Centre, Blackhorse Road, London SE99 6TT.
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www.recycle.mcmail.com/film.htm (塑料容器,包装和胶卷)
Plastic containers, packaging and film
Local authorities across the UK spend over £45M per year collecting and disposing of plastic bottles that could be recovered for recycling and sold to the recycling industry for an estimated £27M. Over 90% of the 470,000 tonnes of plastic bottles used in the UK each year end up in landfill.
"We are often told by councils that plastic bottles are too expensive to collect for recycling. Think about it - these councils are already paying a similar collection charge to pick up the bottles and send them to landfill as part of a traditional waste management service. Most people don’t realise that plastic bottles occupy around 10% of the capacity of household refuse collection vehicles. The real problem here isn't that we can't afford to collect them - the problem is that they are being delivered to the wrong place!", says Andrew Simmons of Recoup.
Like industrial scrap, plastic containers and packaging may be recycled by granulation and making into pellets for remoulding, but contamination and other factors impose economic and technical restraints, not least the great variety of plastics used and the problems of storing, handling and transporting very low density, flammable materials. It takes about 20,000 two-litre drinks bottles or 120,000 plastic carrier bags to make up 1 tonne but despite these difficulties, baled quantities of crushed clean containers, separated by plastic types, can be saleable. They are used for new food packaging (using a ‘sandwich’ of reclaimed material bonded to a barrier film of virgin material), non food packaging products which will tolerate trace contaminants, and products such as carpet fibres and thermal clothing.
Polyethylene (PE) film is the most widely recycled plastics material in the UK. Over 50,000 tonnes per annum are recovered. Recyclable material arises as scrap film or bags in film manufacturing operations, pallet wrap, used bags and sacks and agricultural silage wrap. Most recycling companies require the material to be essentially clean but some companies have washing facilities and can handle soiled material. Pallet shrink-wrap may have paper labels attached and most recycling companies want these only once the paper has been removed. Companies processing mixed plastics can accept mixed and contaminated material (some paper and tapes). Most companies want bulk materials (tonnes), but may accept smaller quantities if delivered.
Soiled packaging films and carrier bags, mainly manufactured from polyethylene, have a high calorific value (similar to petroleum) and burn reasonably cleanly. There is, however, a potential hazard from plastics containing chlorinated compounds, such as PVC (polyvinyl chloride); partly because of additives which can leach out, and because, if burnt, particularly at low temperatures, they can produce toxic chlorine compounds. Despite improved quality control, incinerators still fail temperature and emission standards on a regular basis, and there is no safe limit for dioxin emissions, so burning PVC at all is unwise. Never burn on small scale appliances or on bonfires! Contact your local Environment Agency Office for further guidance if necessary. To distinguish different types of plastic, see section 420, Environmental labelling.