PLASTIC

A SYNTHETIC MATERIAL MADE FROM A WIDE RANGE OF ORGANIC POLYMERS THAT CAN BE MOLDED INTO SHAPE WHILE SOFT AND THEN SET INTO A RIGID OR SLIGHTLY ELASTIC FORM
 

Plastic is produced by manipulating the bonds of carbon atoms to create polymers.  Most plastic is produced by the synthesis of petrochemicals coming from oil, natural gas, or coal.  Chemical catalysts are used to create reactions and additives are mixed in to enhance performance of the final product.
 

Despite being a relatively new commodity, the global manufacture and consumption of plastic has grown exponentially since its introduction into the consumer economy. Today, its main use is consumer product packaging. Being comparatively cheap, lightweight, and durable, plastic possesses highly desirable attributes for this growing market application.
 

There are quite literally countless forms and uses for plastic – industrial, medical, automotive, agricultural, consumer product packaging, etc.  Consumers usually see seven different kinds in everyday products, so identified by their resin identification code (number). Contrary to common belief these resin identification codes do not necessarily indicate a products recyclability, but rather the type of plastic a product is made from.  Recyclability, especially with regard to plastics, can vary greatly from community to community and may change in accordance with market trends.
 

COMMON TYPES OF CONSUMER PLASTICS
 

• #1 Polyethylene Terephthalate (PET)

• #2 High-Density Polyethylene (HDPE)

• #3 Polyvinyl Chloride (PVC)

• #4 Low-Density Polyethylene (LDPE)

  • Linear Low Density Polyethylene (LLDPE)

• #5 Polypropylene (PP)

• #6 Polystyrene (PS)

  • General Purpose Polystyrene (GPPS)

  • High Impact Polystyrene (HIPS)

  • Expanded Polystyrene (EPS)

• #7 “Other” category

  • includes plastics such as nylon, acrylic, polycarbonate (PC), and a bio-based plastic called polylactic acid (PLA)

The most commonly recycled and recyclable plastics are PET and HDPE and, more recently, PP.  Hard to recycle plastics include LDPE, PVC, and PS, with the latter two having negligible recycling rates in the US.
 

PLASTIC RECYCLING PROCESS
 

Plastic recycling is an involved process and differs slightly by type. Generally speaking, once the plastics are sorted by type at a materials recovery facility, the following steps occur:
 

1. Sorted plastics are baled and shipped by a MRF to a plastic recovery facility

2. At plastic recovery facility, bales are broken, and plastic is further sorted to increase value using a variety of techniques:

   • Manual sorting

   • Optical sorting

   • Float/sink tests

   • Density based sorting

3. Plastics are ground into ‘flake’ and washed to remove adhesives, labels, and chemical and food residues.

4. Clean flake is extruded (heated and densified)

5. Dyes or other additives are added, as applicable

6. Final product is pelletized (strung and cut into small pellets) and cooled in water
    

COMMON USES OF RECYCLED PLASTICS
 

• PET – carpet, polyester, bottles, strapping

• HDPE – recycling or waste carts, crates, detergent bottles, pallets, agricultural pipes

• LDPE – film, gardening supplies, shipping materials

• PP – automotive parts, textiles, plastic lumber, strapping
   

Unlike glass or metal, plastic can only be recycled a finite number of times. According to Roland Geyer’s study, “Production, Use, and Fate of all Plastics Ever Made” in the July 2017 edition of Science Advances published by the American Association for the Advancement of Science, an estimated 9% of all plastic produced is recycled, 79% plastic is landfill or incinerated, and the remaining is presumed to exist in the natural environment as litter or marine plastic pollution.
 

As a consumer, it is incredibly important to be educated on what plastics are recyclable and to support the plastic recycling market by buying recycled content plastics where possible and urging product manufacturers to adopt recycled content goals.