Polyethylene Terephthalate (PETE or PET, and PETG)
MOLECULAR FORMULA:
(-CO-C6H4-CO-O-CH2-CH2-O-)nOR
Within the United States PETE is an acronym that is used specifically by manufacturers to mark and identify plastic bottles or containers made from polyethylene terephthlate for the purpose of recycling. The acronym PET is more generally utilized within the chemical industry to designate the plastic material polyethylene terephthalate, which can also be written as poly (ethylene terephthalate). PET is the acronym accepted by standards organizations including
American Society for Testing and Materials International, (ASTM International- formerly just ASTM), and the
International Organization for Standardization (ISO). Nevertheless, the acronyms PETE and PET refer to the same class of plastic materials. In the discussion below, PETE is used in reference to a recyclable container made from PET, while PET refers directly to the plastic material polyethylene terephthlate. However, please note that packaging manufactured outside of the U.S. may utilize the marking PET.
 | Properties: toughness, strength, heat resistance, barrier to moisture and gas. Density: 1.35-1.38 g/cc
Statistic: In 1999 PET accounted for 48% of plastic bottle resin sales, making it the most widely used resin in plastic bottles
Description: PET, also referred to as polyester, is a popular packaging material for food and non-food products because it is inexpensive, lightweight, resealable, shatter-resistant and recyclable. PET is clear and has good moisture and gas barrier properties. Its color may be green. The flakes and pellets of cleaned postconsumer recycled PET are in heavy demand for use in spinning carpet yarns and for producing fiberfill and geotextiles. |
Packaging applications: Soft drink bottles, water bottles, beer bottles, mouthwash bottles, peanut butter containers, salad dressing containers, juice bottles, vegetable oil bottles
Recycled products: Fiber, tote bags, new PETE containers for both food and non-food products, fabric for clothing, athletic shoes, luggage, upholstery, furniture, carpet, fiberfill for sleeping bags and winter coats, industrial strapping, sheet, and film, and automotive parts, such as luggage racks, headliners, fuse boxes, bumpers, grilles and door panels
 | Although the acronym PETE was adopted by manufacturers to identify packaging made from PET, primarily in resposnse to a potential trademark dispute, a recycling symbol that includes the designation PET rather than PETE has been identified on packages of products imported from outside of the US. |
 | PETG is the acronym for polyethylene terephthalate glycol, a co-polymer of PETE. PETG has excellent clarity and is commonly used for containers of products such as shampoos, detergents, soaps, oils and pharmaceutical items. It is a clear amorphous plastic with good resistance to impact. |
(NOTE:
C6H5 in the molecular formula comprises a benzene ring. Benzene is generally considered a carcinogenic substance.)
High Density Polyethylene (HDPE)
MOLECULAR FORMULA:
(-CH2-CH2-)nOR
The C=C double bond in an ethylene monomer is transformed into a C-C single bond in the polymer.
 | Properties: toughness, strength, stiffness, ease of forming, ease of processing, resistance to moisture and chemicals, permeability to gas. Density: 0.94-0.96 g/cc
Statistic: In 1999 HDPE accounted for 47% of plastic bottle resin sales, making it the second most widely used resin in plastic bottles. HDPE and PETE together accounted for 95% of plastic bottle resin usage. |
Description: Bottles made from HDPE come in both pigmented and unpigmented resins. The unpigmented resin is translucent. It also has good stiffness and barrier properties. Thus, it is ideal for packaging products having a short shelf-life such as milk. HDPE's good chemical resistance allows it to be used in containers holding household or inductrial chemicals. The pigmented resin has even better crack resistance and chemical resistance than the unpigmented resin.
Packaging applications: Milk containers, juice bottles, water bottles, bleach, detergent, and shampoo bottles, trash bags, grocery and retail carrying bags, motor oil bottles, butter and margarine tubs, household cleaner bottles, yogurt containers, and cereal box liners
Recycled products: Drainage pipe, liquid laundry detergent bottles, oil bottles, pens, benches, doghouses, recycling containers, floor tile, picnic tables, fencing, lumber, and mailbox posts
 | Plastic bag manufacturers have adopted a somewhat different symbol identification for HDPE as shown at the left. |
Polyvinyl Chloride (PVC, sometimes V)
MOLECULAR FORMULA:
(-CH2-CHCl-)nOR
The C=C double bond in each monomer is transformed into a C-C single bond in the polymer.
The V in the first (and original) symbol actually stands for vinyl, however, the plastic resin is usually referred to as polyvinyl chloride (PVC) and therefoere the symbol has evolved to the resin designation of PVC.
 | Properties: toughness, strength, ease of blending, ease of processing, resistance to grease, oil, and chemicals, clarity. Density: 1.32-1.42 g/cc
Statistic: In 1999 PVC accounted for 2% of plastic bottle resin sales.
Description: Vinyl, or polyvinylchloride, has stable electrical and physical properties. It has excellent chemical resistance and good weatherability. Its flow characteristics make it well-suited for injection molding. |
Packaging applications: Window cleaner bottles, cooking oil bottles, detergent bottles, shampoo bottles, clear food packaging, wire and cable jacketing, medical tubing, with additional significant usage in household products and building materials, particularly siding, piping, and windows
Recycled products: Binders, decking, paneling, mudflaps, roadway gutters, flooring, cables, speed bumps, and mats
NOTE: The
Cl (chlorine atom) in the molecular formula renders PVC a potentially toxic material when it is burned. The burning of PVC can result in the creation of dioxins, a material that is considered highly carcinogenic.
Low Density Polyethylene (LDPE)
MOLECULAR FORMULA:
( - CH2 - CH2 - )n
 | Properties: toughness, strength, flexibility, ease of sealing, ease of processing, barrier to moisture. Density: 0.91-0.93 g/cc
Statistic: In 1999 LDPE accounted for just 1% of plastic bottle resin sales. |
Description: Because of its toughness , flexibility, and transparency, LDPE is commonly used in applications where heat sealing is necessary. It is also widely used in wire and cable insulation and jacketing.
Packaging applications: Squeezable bottles, breadbags, frozen food bags, tote bags, clothing, furniture, dry cleaning bags, and carpet
Recycled products: Film and sheet, loor tile, garbage can liners, shipping envelopes, furniture, compost bins, paneling, trash cans, lumber, landscaping ties
 |  | Plastic bag manufacturers have adopted somewhat different symbol identifications for LDPE bags as shown at the left. |
(NOTE: The molecular formulas for LDPE and HDPE are the same. The difference in the plastics is the density of the molecular chains. The density varies in the manner in which the polymeric chains form. In HDPE the chain is essentially one long continuous chain, allowing the strands to fold back upon one another and densely occupy space. In LDPE the chains have multiple branches, which interfere with a neatly organized packing of chains. Instead the packing is more disorganized, occupying more space and thus resulting in a lower density.)
 | Plastic bag manufacturers are also making their products using low low density polyethylene, a symbol for which appears to the left. As you might guess, low low density polyethylene has a molecular density even less than low density polyethylene. |
Polypropylene (PP)
MOLECULAR FORMULA:
(-CHCH3-CH2-)nOR
The C=C double bond in each monomer is transformed into a C-C single bond in the polymer.
 | Properties: toughness, strength, resistance to heat, grease, oil, and chemicals, barrier to moisture. Density: 0.90-0.92 g/cc
Statistic: In 1999 PP accounted for 2% of plastic bottle resin sales. |
Description: Polypropylene has the lowest density of the resins used in packaging. It is strong and is resistant to chemicals. Since it has a high melting-point it can be utilized in applications requiring that a container be filled with a hot liquid.
Packaging applications: Yogurt containers, syrup bottles, ketchup bottles, caps, straws, medicine bottles
Recycled products: Signal lights, battery cables, brooms, brushes, auto battery cases, ice scrapers, landscape borders, bicycle racks, rakes, bins, pallets, and trays
 | An alternative recycling symbol for polypropylene utilizing the original design for the mobius arrows, but inverted, is shown to the left. |
Polystyrene (PS)
MOLECULAR FORMULA:
(-CHC6H5-CH2-)nOR
The C=C double bond in each monomer is transformed into a C-C single bond in the polymer.
 | Properties: ease of forming, clarity, low heat transfer, good thermal insulation. Density: 1.03-1.06 g/cc
Statistic: In 1999 PS usage as a plastic bottle resin was essentially nil. |
Description: Polystyrene can be made into rigid or foamed products. It has a relatively low melting point.
Packaging applications: Plates, cups, cutlery, meat trays, egg cartons, carry-out containers, aspirin bottles, compact disc jackets
Recycled products: Thermal insulation, light switch plates, egg cartons, vents, rulers, foam packing, carry-out containers
(NOTE:
C6H5 in the molecular formula comprises a benzene ring. Benzene is generally considered a carcinogenic substance.)
Other
 | Properties: varies according to constituent resins
Statistic: In 1999 there was minimal usage of resins in the 'other' category in plastic bottles. |
Description: The category of "Other" includes any resin not specifically numbered 1, 2, 3, 4, 5, or 6, or combinations of one or more of these resins.
Packaging applications: Three and five gallon water bottles, certain food product bottles
Recycled products: Plastic lumber, custom-made products
Resin Symbols without Acronyms
You may come across recycling symbols that only indicate a number without an acronym for the plastic resin. The plastic resin of containers or packing labeled in this manner can be identified by this number and although not as informative compared to an acronym listed below the symbol, it is certainly a workable means of identifying and classifying recyclable plastics.
Alternative Plastic Resin Recycling Symbols
An altenative recycling symbol for plastic resins may be encountered embodying the original mobius three-chasing arrows together with a number in the center. These symbols may appear with or without a descriptive acronym.
R-resins: ALREADY RECYCLED
You may ask, all those plastic bottles that are recycled, or those newspapers, what happens to them? Generally, a product that is recycled is remanufactured into a new product that has less demanding specifications for the new use of the recycled product. In the case of paper products, the white copy paper may end up as newsprint. Newsprint may end up as toilet paper. Plastic materials may be recycled into a packaging material of less stringent requirements. Thus, resins that have become a recycled product, are further identified with an R in front of the previous designation in order to denote that the material has already been recycled. The symbols identifying these products are shown above. As an example, RHDPE is the acronym interpreted as recycled high density polyethylene. However, keep in mind that the R-materials still have potential for further recycling.
Acrylonitrile Butadiene Styrene (ABS)
 | Properties: resilient, low density, rigid, impervious |
Description: Acrylonitrile butadiene styrene was not part of the original resin identification system.
Applications: Pipes, car bumpers, toy building blocks, golf club heads, enclosures
(NOTE: The three components of ABS, acrylonitrile, butadiene and styrene are considered probable human carcinogens.)
Origin of the recycling symbol
The original recycling symbol was designed in 1970 by Gary Anderson, a senior at the University of Southern California at Los Angeles. It was submitted to the International Design Conference as part of a nationwide contest for high school and college students sponsored by the Container Corporation of America. The contest was a result of continuing growth of consumer awareness and environmentalism and a response to the first Earth Day.
The recycling symbol represents a Mobius loop consisting of three-chasing-arrows in the shape of a triangle having rounded vertices. Each arrow twists and turns itself, and all three arrows chase each other. It is a consummate representation of recycling. The mobius loop itself was discovered in 1858 by
August Ferdinand Möbius (1790-1868), a German mathematician and astronomer, and has been a mathematical marvel of simplicity, singularity, and continuity ever since.
Meaning of the recycling symbol
Each of the three arrows can represent one step in a three-step process that forms a closed loop, the recycling loop. The first step represents collection of materials to be recycled. This step takes place when recyclable materials are placed into your curbside recycling bin or taken to a local collection center. The collected materials are then cleaned and sorted for sale to a manufacturing facility. The manufacturing process is the second arrow in the recycling symbol. The recyclable materials are manufactured into new products for retail or commercial sale. The third step is the actual purchase and use of the products made from the recycled materials. The loop is now complete.
Remember the three R's- Reduce, Reuse and Recycle
Evolution of recycling symbols
The present resin identification coding system that is detailed above was introduced by the
Society of the Plastics Industry (SPI) in 1988 at the urging of recyclers around the country. In an effort to decrease the volume of waste subject to tipping fees at landfills, a growing number of communities were implementing recycling programs. These programs were often driven by state-level recycling mandates. The resin identification code was developed to meet recyclers needs while providing manufacturers a consistent, uniform system that could apply nationwide.
The resin identification coding system offered a means of identifying the resin content of bottles and containers commonly found in the residential waste stream. By identifying the resin content, consumers would know what types of plastic packaging were being utilized, and hence, which ones could be recycled. Consumers were, and will always be, the first line of action in any effective recycling program. The bulk recyclers would also filter the incoming stream of post consumer recyclables by looking at the code on the plastic packaging.
Since the first recycling symbol was designed, and the plastic resin codes introduced, certain industries have developed unique symbols specific to an industry. For example, industry associations for glass, for paperboard, and for corrugated materials have all developed, and in some cases trademarked, unique recycling symbols. These three separate symbols can all be classified as 'recyclable' symbols.
Miscellaneous recycling symbols
 | A generic form of the plastic resin identification codes without the number is also being utilized to designate recyclability of products that aren't plastic. Usually there is descriptive text designating the particular content. |
|
In a further twist to the evolution of recycling symbols, at least one individual company has promulgated its own version of a 'recycled' symbol. Hewlett-Packard identifies its packaging materials with a symbol that is similar to the 'recyclable' symbol for plastic resins. In the 'recycled' symbol that is depicted the basic material is of course paper. The first number of the pair tells the minimum percentage of post-consumer recycled content (in this case 50%), while the second number denotes the total recycled content (in this case 80%). Other materials, including plastics, are identified with an appropriate labeling. |
 | The symbol with the blue background shows the three arrows in a planar context. This particular symbol is a relatively new arrival. |
 The Rechargeable Battery Recycling Corporation (RBRC) is a non-profit, public service organization that promotes the recycling of portable rechargeable batteries. These batteries are typically found in cordless power tools, cellular and cordless phones, laptop computers, camcorders, digital cameras, and remote control toys. Nickel cadmium (Ni-Cd) batteries, nickel metal hydride (Ni-MH) batteries, lithium ion (Li-ion) batteries, and small sealed lead (Pb) batteries weighing less than 2 lbs are all accepted for recycling. Please keep in mind that batteries CAN NOT be deposited for recycling in a curbside recycling container with other recyclable products. Batteries must be delivered to a battery collection site. Visit the RBRC website to find a nearby collection site or call the phone number shown on the recycling symbol. The collection sites are widely available and include large well-known retailers such as Sears, Home Depot, Wal-Mart and Target among others. |
The 'Green Dot' (Der Grüne Punkt)
 The green dot (in German- der grüne punkt) was orignally developed by Duales System Deutschland AG, a privately owned non-profit German company, in 1991. It has since been adopted by other countries of the European Union including Austria, Belgium, France, Germany, Ireland, Luxembourg, Portugal, Spain and Sweden. It has also been adopted in the non-EU countries Latvia, Norway, the Czech Republic, Hungary and Poland.
In 1995, a general license for the 'green dot' was transferred to Packaging Recovery Organisation Europe s.p.r.l., otherwise known as PRO EUROPE, having its headquarters in Brussels, Belgium. PRO EUROPE licenses the 'green dot' to nationally recognized systems set up in European Member States to implement the European Directive on Packaging and Packaging Waste dated December 20, 1994, with the further objective of making the 'green dot' at least a pan-European trademark.
The 'green dot', as utilized in Europe, carries a somewhat different meaning than the recycling symbols used in the United States. The presence of a 'green dot' symbol on packaging denotes that the manufacturer of the package has purchased a license for the right to use the 'green dot' trademark. The cumulative license fees fund a system of not only recovering and recycling packaging materials, but also of minimizing the use of packaging material, and of creating packaging that is easier to recycle. |
