Plastics can be divided into two general categories--thermoplastics and thermosets.
- Thermoplastics can be mechanically recycled (through application of heat and pressure) into new manufacturing feedstock.
- Thermosets cannot be mechanically recycled because of chemical bonds binding the plastic molecules (monomers) together.
Commodity Grade Plastics
The resin types included in commodity grade plastics are identified in the resin coding system developed by the Society of Plastics Industries (SPI) shown below:
Commodity Grade Plastics SPI Resin Code
- Polyethylene Terephthalate (PETE ) #1
- High Density Polyethylene (HDPE) #2
- Polyvinyl Chloride (PVC) #3
- Low Density Polyethylene (LDPE) #4
- Polypropylene (PP) #5
- Polystyrene (PS) #6
The Institute of Scrap Recycling Industries, Inc. (ISRI) publishes specifications and commercial guidelines for 27 categories of recycled plastic scrap purchased and/or sold in the United States and Canada. The publication Scrap Specifications Circular 1998 can be purchased directly from ISRI.
The primary source for postconsumer commodity grade plastic is from containers collected through curbside recycling programs, buyback centers, and film collected from agricultural operations, retail grocery stores, warehouses, distribution centers, and manufacturing facilities. Prices for containers are divided into two categories: loose containers and baled containers. Baling plastic bottles increases density; and, as a result, decreases transportation costs.
Postconsumer plastic is sorted, chopped, and washed at a plastic reclaiming facility (reprocessor). The reclaiming facility produces three categories of plastic feedstock used in the manufacturing of new plastic products. The three categories of plastic feedstock are:
- Flake--chopped plastic containers.
- Powder--pulverized flake.
- Pellet--flake that is mechanically melted, extruded, and cut into beads.
The Federal Food and Drug Administration (FDA) maintains a list of companies that have received FDA approval to manufacture and sell recycled--content plastic containers in food contact applications. For more information, please contact the Center for Food Safety and Applied Nutrition at (202) 205-5140.
Engineering Grade Plastics
Engineering grade plastics are recovered principally from two durable good waste streams: brown goods (computers and electronics) and automobiles. Engineering grade plastics contain blended resins and/or additives that increase properties such as chemical resistance, rigidity, and fire and impact resistance. The development of automated identification and sorting technology has increased the economic competitiveness of postconsumer plastic recovered from these waste streams. The following engineering grade plastics are covered in this marketing guide:
Standard Industrial Classification (SIC) Codes
The U.S. Department of Labor Statistics provides a searchable database to identify industries and establishments associated with resin production, distribution and use. Standard Industrial Classification (SIC) codes are provided for these entities.