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TABLE 6.8
Other Products Manufactured from Recycled Plastics

Impact barriers
Docks, decks
Fences
Scuff boards, floor boards
Boundary markers, right of way markers
Signposts
Benches and picnic tables
Fiberfill for sleeping bags
Plastic lumber
Flowerpots
Containers for nonfood products
Mats
Strapping
Scouring pads
Toys
Compost bins
Recycling containers

resins in plastic food containers. The FDA has allowed for only limited use of recycled polymers in
food container manufacture due to concerns about possible food contamination. Recycled contain-
ers have been used in soda bottles, tubs for butter, and detergent bottles. Recycled resins in nonfood
containers continue to increase in popularity (APC, 2002).
Plastic lumber has become popular over the past decade. Plastic lumber is made by extrusion
and contains either single or mixed resins. Such lumber possesses physical characteristics similar
to those of standard wood lumber. The advantages of plastic lumber are that it is resistant to the ele-
ments, water, and insect damage. Less maintenance (painting, etc.) is required. However, plastic
lumber is relatively costly compared with its natural counterpart. There are also some concerns that
plastic timbers may bend slightly with time.

6.11.7 PROCESSING FOR RECYCLING
Postconsumer plastics can replace or supplement virgin plastic resins. Plastics recycling is difficult
because each type of plastic must undergo a different process before becoming a new product.
There is a major concern with contamination as well. Plastics are typically segregated by resin type
and ideally by production method (e.g., extrusion vs. injection). Different resins possess differing
physical characteristics including melting points, tensile strength, shatter resistance, and so on.
Buyers often require that plastics are color-separated with no contamination (Rhyner et al., 1995).
There are seven major types of plastics, created by a voluntary labeling system to encourage
recycling. Types are indicated by a recycling logo (the three chasing arrows) with a number from 1
to 7 situated in the center (Figure 6.12). As noted above, polyethylene PET and HDPE are the pre-
dominantly recycled polymers. Postconsumer items made from PET and HDPE resins have devel-
oped stable markets in the United States and Asia.
Postconsumer plastics are recovered from collection centers loose in wire mesh cages but more
typically baled to reduce volume. After breaking bales, containers are deposited along a conveyor
belt for final sorting. Undesired plastics and extraneous wastes are removed manually. Plastics are
also sorted by color.
Plastics can be recycled in several ways. In HDPE recycling, containers are chipped to small flakes
by a granulator designed to cut chips without causing excessive heat that might fuse the particles. The