| The coding system was launched in 1988 by the Society of the Plastics Industry (SPI) in the United States, and has since been adopted by industry groups in Australia, Canada, Europe, New Zealand, South Africa and Japan. Two of the key issues are the need to make it more specific (ie. to distinguish between grades of polymer) and to avoid confusion with established recycling symbols.
This coding sytem (see below) is only intended for use on packaging. Other systems are being developed for plastics in general. There is a draft international standard ISO/DIS 11469 called "Plastics - Generic Identification and Marking of Plastic Products" | TYPE OF PLASTIC | CHARACTERISTICS | APPLICATIONS |  | Polyethylene Terephthalate
PET | Clear, tough, solvent resistant, often us as a fibre | Carbonated soft drink bottles, pillow and sleeping bag filling, textile fibres |  | High Density Polyethylene
HDPE | Hard to semi-flexible, waxy surface, opaque, melts at 135°C | Crinkly shopping bags, freezer bags, milk bottles, bleach bottles, buckets, rigid agricultural pipe, milk crates |  | Unplasticized Polyvinyl Chloride
UPVC | Hard rigid, can be clear, can be solvent welded | Electrical conduit, plumbing pipes and fittings, blister packs, clear cordial and fruit juice bottles | | Plasticized Polyvinyl Chloride
PPVC | Flexible, clear, elastic, can be solvent welded | Garden hose, shoe soles, cable sheating, blood bags and tubing, watch straps |  | Low Density Polyethylene
LDPE | Soft, flexible, waxy surface translucent, withstands solvents | Garbage bags squeeze bottles, black irrigation tube, black mulch film, garbage bins |  | Polypropylene
PP | Hard but still flexible, waxy surface, melts at 145°C, translucent, withstands solvents. Very versatile material with many applications | Potato crisps bags, drinking straws, microwave ware, plastic kettles, plastic garden settings, baby baths, plastic hinged lunch boxes |  | Polystyrene
PS | Clear, glassy, rigid, brittle, opaque semi-tough, melts at 95°C. Affected by fats and solvents | Plastic cutlery, imitation 'crystal glassware', low cost brittle toys | | Expanded Polystyrene
EPS | Foamed, light weight, energy absorbing, heat insulating | Panel insulation, produces boxes, protective packaging for fragile items |  | OTHER : Includes all other resins and multi materials (eg laminates). Examples are polyamide, acrylonitrile butadiene styrene (ABS), acrylic, nylon, polyurethane (PU) and phenolics. | |