What do those numbers mean?
Plastic products have many uses in today's society, including some considered
indispensable. However, there is a down side to plastic. One-third of all plastic is used for
items with a lifespan of less than one year and very little plastic is recycled. In San
Francisco, less than 2% of the 85 million pounds of plastic we use every year is recycled.
There are 200 different plastic resins, but most consumer products made from plastic fall
into one of 6 categories.
The Society for the Plastics Industry came up with a labeling system for plastics a
number of years ago. This system, which uses the numbers from 1 to 7 (7 is used for
anything that doesn't fall into the 6 common categories) surrounded by recycling arrows,
was designed to identify the different types of plastic resins so that they could be more
easily recycled when recycling systems came into place. The six common resins, #1 Polyethylene Terephthalate (PET), #2 - High Density (HDPE), #3 - Polyvinyl Chloride
(PVC), #4 - Low Density Polyethylene (LDPE), #5 - Polypropylene (PP) and #6 Polystyrene (PS), are all manufactured using different processes and cannot be mixed
together and recycled. So, for example, if one shampoo bottle is included with a load of
soda bottles, it could contaminate the whole load and make it unrecyclable.
However, even though most plastics are technically recyclable, the recycling
infrastructure for plastics is in its infancy. Less than 3 percent of the 60 billion pounds of
plastic produced nationwide every year are actually recycled. And although plastics made
up a minute percentage of the waste stream in 1960, by 1992, plastics occupied more than
20% of landfill space nationwide. This percentage is continuing to grow, and the
Environmental Protection Agency estimates that a quarter of our garbage will be plastic
by the turn of the century.
Reference: http://www.sfrecycle.org/info/plastics.html
The plastic types were defined by the Society of the Plastics Industry (SPI)
http://www.socplas.org/:
Type 1
Type 5
PETE Polyethylene
Terephthalate (PET)
HDPE High-Density
Polyethylene
V Vinyl/Polyvinyl Chloride
(PVC)
LDPE Low-Density
Polyethylene
PP Polypropylene
Type 6
PS
Type 7
OTHER Usually layered or
mixed plastic.
Type 2
Type 3
Type 4
Polystyrene
Soda & water containers, some waterproof
packaging.
Milk, detergent & oil bottles. Toys and plastic
bags.
Food wrap, vegetable oil bottles, blister
packages.
Many plastic bags. Shrink wrap, garment bags
Refrigerated containers, some bags, most bottle
tops, some carpets, some food wrap.
Throwaway utensils, meat packing, protective
packing.
No recycling potential - must be landfilled.
Types 1 and 2 are commonly recycled. Type 4 is less commonly recycled. The other
types are generally not recycled, except perhaps in small test programs. Common plastics
polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) do not have recycling
numbers.
The code must be molded into the plastic item. The symbol should be easily visible for
sorting purposes. The best symbols are large with a different surface finish than the
surrounding plastic. If the container has a matte surface (rough), then the symbol should
be smooth, a smooth container should have a rough recycling symbol.
Understand that plastic recycling is really in infancy. The process is messy and
inefficient. Numerous problems exist. For example plastic from a "blow mold" (the neck
of the bottle is narrower than the body) has a slightly different structure from the exact
same plastic used in an "injection mold" (where the opening is the widest part of the
product). Because of low processing temperatures plastic is highly vulnerable to
contamination by food, labels and different plastics.
Reference: http://www.obviously.com/recycle/guides/cryptic.html