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By Angela Perkins,2014-11-21 23:20
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Click here to learn more about the 7

    Plastic resin identification codes and plastic recycling

    July 16, 9:29 AM ? Clay Miller - Louisville Green Living Examiner

    You've probably noticed on most plastic products a recycling symbol with 1, 2, 3, 4, 5, 6 or 7 along with letters. So what are these exactly? The SPI resin identification coding system is a set of symbols placed on plastics to identify the polymer type. The symbols used in the code consist of arrows that cycle clockwise to form a rounded triangle and enclosing a number, often with an acronym representing the plastic below the triangle. When the number is omitted, the symbol is known as the universal Recycling Symbol, indicating generic recyclable materials. It was developed by the Society of the Plastics Industry (SPI) in 1988, and used internationally. Let's take a look at the 7 plastic identification codes.

    Plastic Type of plastic Common Packaging Identification Properties polymer Applications Code

    Polyethylene Clarity, strength, Soft drink, water and salad

    Terephthalate toughness, barrier to dressing bottles; peanut butter and

    (PET, PETE) gas and moisture. jam jars

    Stiffness, strength, High Density toughness, resistance to Milk, juice and water bottles; trash Polyethylene moisture, permeability and retail bags. (HDPE) to gas.

    Versatility, clarity, ease Polyvinyl Juice bottles; cling films; PVC of blending, strength, Chloride (PVC) piping toughness.

    Ease of processing,

    Low Density strength, toughness, Frozen food bags; squeezable

    Polyethylene flexibility, ease of bottles, e.g. honey, mustard; cling

    (LDPE) sealing, barrier to films; flexible container lids.


    Strength, toughness, Reusable microwaveable ware;

    resistance to heat, kitchenware; yogurt containers; Polypropylene chemicals, grease and margarine tubs; microwaveable (PP) oil, versatile, barrier to disposable take-away containers;

    moisture. disposable cups and plates.

    Egg cartons; packing peanuts;

    Versatility, clarity, disposable cups, plates, trays and Polystyrene (PS) easily formed cutlery; disposable take-away


    Other (often Dependent on polymers Beverage bottles; baby milk polycarbonate or or combination of bottles; electronic casing. ABS) polymers

Source: Wikipedia: Plastic recycling

    Most plastics can be recycled, but they have to be separated into their different polymer types. Contrary to misconceptions, the number does not indicate how hard the item is to recycle, nor how often the plastic was recycled. It is an arbitrary number and has no other meaning aside from identifying the specific plastic.

    Use of the recycling symbol in the coding of plastics has led to ongoing 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 (Los Angeles, for example, recycles all clean plastics numbered 1 through 7).

When recycling plastic:

    ; Rinse and sort your plastic containers by number. Recyclable plastic often must be

    separated by number in order to avoid contamination as it begins the recycling process

    ; Recycle type 1 (PETE) and type 2 (HDPE) plastic containers at your curb

    ; Drop off plastic grocery bags - usually type 4 (LDPE), sometimes type 2, though not

    always marked - at your grocery store to be recycled

    ; Most recycling programs do not recycle types 3, 5 and 7. While some of these are

    recyclable, the plastics industry is still in the early stages of recycling and does not

    recycle these in most cities unless it is through a test program.

    ; Note that types 1, 3, 6 and 7 have shown that they can leach chemicals onto other items;

    making them not as safe as other plastic types

    ; For type 6, call the Alliance of Foam Packaging Recyclers, (410) 451-8340, or look at the

    expanded polystyrene (EPS) packaging drop off locations to find the nearest type 6 drop

    off center to you.

    ; Take caps and pump spray tops off of plastic containers unless they are marked with a

    number. They are often made from a type of plastic that is different from the main part of

    the container and generally are not recyclable

    Hopefully in the near future more cities will be able to recycle all types of plastic. The quantity of post-consumer plastics recycled has increased every year since at least 1990. In 2006 the amount of plastic bottles recycled reached a record high of 2,220,000,000 pounds. The amount of PET bottles recycled in 2006 increased more than 102 million pounds compared to 2005. HDPE bottle recycling increased in 2005 to 928 million pounds. All plastic bottles were recycled at a rate of 24 percent in 2005. In order to get plastic out of landfills and elsewhere we need to recycle more plastic. Also, use more eco-friendly products rather than using plastic. Copyright 2009 All rights reserved. This material may not be published, broadcast, rewritten or redistributed.


Clay Miller is an Examiner from Louisville. You can see Clay's articles at:


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