Plastic Identification Numbers… What Do They Mean?

By | April 21, 2010

Over the past few months we have heard a lot of talk about the numbers printed on plastic containers which supposedly indicate the type of polymer material used to manufacture the plastic container… and only a few weeks ago we posted a blog entry about how someone needs to step in and enforce the numbering system since some companies have decided to intentionally mislabel their products so environmentally people would continue to purchase them.

Most people all seem to want to know the same thing: “What do the recycling numbers on plastic containers mean?”

The graphic on the left tells you what family of plastic/polymer materials belong to each number… but that does you no good if you don’t speak polymerese or plasticsese so we will now provide you with a listing of what all those abbreviations mean:

  • PETE — Polyethylene Terephthalate (AKA: PET). Example: Soft drink bottles.
  • HDPE — High Density Polyethylene. Example: Grocery bags and milk jugs.
  • LDPE — Low Density Polyethylene. Example: Plastic rings that holds a six-pack of cans together.
  • V — Polyvinyl Chloride (AKA: PVC). Example: PVC pipe used for plumbing.
  • PP — Polypropylene. Example: Auto parts.
  • PS — Polystyrene. Example: Plastic utensils.
  • OTHER — Fiberglass, polycarbonate materials, nylon materials.

Wondering which materials actively get recycled and which do not?

“Use of the recycling symbol in the coding of plastics has led to on going consumer confusion about which plastics are readily recyclable. In most communities throughout the United States, PETE and HDPE are the only plastics collected in municipal recycling programs. Some regions, though, are expanding the range of plastics collected as markets become available.” ( source )

Now you may find yourself asking, “OK, but what if the plastic part I have on my desk does not have a number on it?”

For industrial and commercial customers, polymer and plastics identification services offered by companies like Polymathic Analytical Labs allow them to quickly learn the identity of the base polymer material (i.e. PET, PVC, etc.) used to manufacture a part and determine how much, if any, inorganic filler material the part contains.

Polymer identification and characterization also works quite well for performing QA/QC checks on incoming lots of manufactured parts.

Interested in having a polymer or plastic material identified? The following resources may come in handy:

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