Monday, May 11th, 2009

What’s in a Number 7?

History of 7

In 1988, SPI developed the resin identification coding system to label different polymers used in plastic goods.  At the time, the majority of plastic packaging was made of one of six resins: polyethylene terephthalate (PETE); high density polyethylene (HDPE); polyvinyl chloride (PVC or vinyl); low density polyethylene (LDPE); polypropylene (PP); or polystyrene (PS), which were labeled with resin ID codes 1 through 6, respectively.  The number 7 was a catch-all number for resins that could be identified as “other” — either a combination of more than one of the six resins listed or a resin that is not listed at all. Watch a video on rein identification basics.

7 of Today

The number 7 still maintains the identification of “other,”  but with the development of plastics technology, several new resin types fall into the number 7 category. These include polycarbonatecomposite material – known as fiber-reinforced polymer (FRP) or glass-reinforced plastic (GRP) – and polylactic acid (PLA).

There are a few misconceptions about the number 7 today:

  • 7 means it has BPA“’ -  Wrong.  Not all number 7 plastics are the same. In fact, the opposite is true. The number 7 code, since it encompasses all types or combinations of resins not identified in numbers 1 through 6, could be anything from acrylics to bioplastics to nylon. Many different types of items could contain plastic with the number 7 – such as parachutes, Tupperware, women’s nylons and windshields. 
  • 7 means it can’t be recycled” – Nope. Most electronic waste that may be made of #7 plastic (such as keyboards, CDs, cell phones, etc.) can be accepted for e-waste recycling programs through some electronic stores or computer retailers. Number 7 plastic products can also be recycled into such useful goods as floor coverings; road, highway and parking products including road barricades and car stops and plastic lumber.

7 of Tomorrow

In an effort to gain input from the stakeholder community, SPI has taken its resin identification codes to ASTM International. Through ASTM, a recognized standards making body, work on developing a standard practice has begun that will educate and offer guidance on the resin identification codes. With the development of several new plastic resins over the past 20 years, participants in this ASTM process may ultimately determine that new, additional code numbers for resins currently housed under number 7 are appropriate. Read more about the ASTM effort to establish a new standard to facilitate more efficient recycling of a variety of post-consumer plastics.

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