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There are over thirty major (large-volume) family types of plastic produced commercially today. The two major groups are thermoset plastics (which cannot be recycled) and thermoplastic polymers (which can be recycled). A smaller third, but growing, category are those derived from biomass. Most of the products from this category are derivatives of cellulose or modified starch. Recently, two new families of plastics derived from corn—polylactic acid (PLA) and polyhydroxyalkonates (PHA)—have been developed and are being used to replace hydrocarbon-derived thermoplastics in a variety of applications.
This report covers the thermoplastic families of
- Polyethylene terephthalate, a polyester resin (PET)
- Polyethylene (HDPE, LDPE, HP-LDPE, LLDPE)
- Polypropylene (PP)
- Polystyrene (PS)
- Polyvinyl chloride (PVC)
Commodity thermoplastic resins are unique among commonly used materials in their ability to be recovered and recycled. In this report, recycling is defined as including mechanical (physical) recovery, chemical (depolymerization to monomer) recovery, thermal (pyrolysis to basic feedstocks) recovery and incineration with energy recovery. Although the chemical and pyrolysis processes have the potential to be very attractive recovery routes that eliminate many of the technical and quality limitations encountered with mechanically recycled plastic resins, they are not being used extensively globally. However, the cumulative effect of plastics recycling on the global consumption of thermoplastic resins has been negligible in terms of virgin resin displacement. Part of this is due to new markets being developed for recycled materials. It will take wider institution of recycling technologies that essentially produce “virgin” resin (e.g., chemical depolymerization) before virgin resin displacement occurs.
Postconsumer PET is the most recycled plastic globally, with a well-developed recovery infrastructure in developed nations. Postconsumer HDPE is the second-most-recycled plastic in the world. Combined, recycled PET and HDPE account for nearly 99% of the global bottle recycling capacity, and nearly 70% of total postconsumer plastics recycling.
The following graph shows the percentage of PET recycled in the world’s top seven recycling countries:
The United States is fifth in terms of the percentage of PET recycled, well behind Japan, Brazil, Europe, and Argentina. In Europe, recycling is part of the consumer’s daily routine. In the United States, convenience (disposal) is still favored over recycling. However, there is a growing attention to sustainability, and a renewed focus on recycling plastics. This has come about as a result of the high price of oil, global warming and industrial initiatives. For example, Wal-Mart has launched a sustainability campaign with pledges to reduce the size of packages and increase its use of recycled materials in an effort to save energy and reduce carbon dioxide emissions. Bottlers in general have reduced PET bottle weight by 33%. Despite these initiatives, legislation such as bottle bills and plastic bag bills will likely be needed to increase consumer participation in recycling. In the United States, plastic manufacturers have moved proactively to process scrap material in-house in the production of plastic products.
China currently produces 85% of the world’s recycled PET fiber. China’s capacity to convert rPET to polyester fiber more than tripled between 2002 and 2007. China is the final destination of 70% of the world’s plastic waste. China is estimated to have recycled 8 million metric tons of domestic plastic waste in 2007. Despite this massive figure, very little information is available on plastics recycling in China. China banned imports of postconsumer plastic bag and film waste in 2007.
Globally, the plastics recycling business is still largely regionalized and located primarily within centers of high population density for feedstock acquisition. Achieving a balance between supply and demand for recycled plastics is critical to the longer-term viability of regional collection programs. High transportation costs for low-bulk-density plastics material dictates the economic boundaries of feedstock acquisition. Local/regional granulation facilities have been evaluated as a way to offset the high freight costs of baled plastics.
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