WE HAVE BEEN USING POLYPROPYLENE (PP) TO PRODUCE CUPS
Polypropylene (PP), a polymer prepared catalytically from propylene which differs from HDPE by having an isostatic replacement of a hydrogen atom by a methyl group on alternate carbon atoms in the main chain. Although largely unreactive chemically the presence of the methyl groups makes Polypropylene slightly more susceptible to attack by strong oxidizing agents than HDPE. A major advantage is Polypropylene's higher temperature resistance, this makes PP particularly suitable for items such as trays, funnels, pails, bottles, carboys, cups and instrument jars that have to be sterilized frequently for use in a clinical environment. Polypropylene is a translucent material with excellent mechanical properties and it has gradually replaced the polyethylenes for many purposes.
To help identify different plastics, manufacturers stamp a Plastics Identification Code on their products. This code is a number inside a triangle with chasing arrows. These codes only identify the product and do not indicate that the product can be recycled. The codes for the seven most common plastics are shown in the table further down this page.
Some uses for plastics and recycled plastics
Plastic Code |
Name of plastic |
Description |
Some uses for virgin plastic |
Some uses for plastic made from recycled waste plastic |
|
polyethylene terephthalate PET |
Clear, tough plastic, may be used as a fibre. |
Soft drink and mineral water bottles, filling for sleeping bags and pillows, textile fibres. |
Soft drink bottles, (multi-and mono-layer) detergent bottles, clear film for packaging, carpet fibres, fleecy jackets. |
|
high density polyethylene HDPE |
Very common plastic, usually white or coloured. |
Crinkly shopping bags, freezer bags, milk and cream bottles, bottles for shampoo and cleaners, milk crates. |
Compost bins, detergent bottles, crates, mobile rubbish bins, agricultural pipes, pallets, kerbside recycling crates, moulded products. |
|
unplasticised polyvinyl chloride UPVC |
Hard, rigid plastic may be clear. |
Clear cordial and juice bottles, blister packs, plumbing pipes and fittings. |
Detergent bottles, tiles, plumbing pipe fittings, shoes. |
|
plasticised polyvinyl chloride PPVC |
Flexible, clear, elastic plastic. |
Garden hose, shoe soles, blood bags and tubing. |
Hose inner core, industrial flooring. |
|
low density polyethylene LDPE |
Soft, flexible plastic. |
Lids of ice-cream containers, garbage bags, garbage bins, black plastic sheet. |
Film for builders, industry, packaging and plant nurseries, bags, agricultural piping. |
|
polypropylene PP |
Hard, but flexible plastic - many uses. |
Ice-cream containers, potato crisp bags, drinking straws, hinged lunch boxes. |
Compost bins, kerbside recycling crates, worm factories, plant pots, automotive parts. |
|
polystyrene PS |
Rigid, brittle plastic. May be clear, glassy. |
Yoghurt containers, plastic cutlery, imitation crystal 'glassware'. |
Clothes pegs, coat hangers, office accessories, spools, rulers, video/CD boxes. |
|
expandable polystyrene
EPS |
Foamed, lightweight, energy absorbing, thermal insulation |
Hot drink cups, takeaway food containers, meat trays, packaging. |
Produce boxes, waffle pods used in building. |
|
other |
Includes all other plastics, including acrylic and nylon. |
Fence posts, outdoor furniture, injection moulded products, agricultural piping. |
|
