Rigid Plastics

The average household produces 6.82 kilograms of plastic containers per year. Plastic containers consists of 1.89% of the total waste stream and locally 89.27% of all plastic containers produced are recovered.

Plastic comes in many different forms. The resin used in making the plastic distinguishes one type from another. In order to make recycling easier, plastic manufacturers are now using a standardized coding system on plastic containers to identify resin types. The code consists of a number surrounded by the chasing recycling arrows (mobius loop) and letters underneath that tells recyclers and the public at a glance what kind of plastic was used to make the container.

What is Acceptable?

Presently, only rigid plastic bottles with the following numbers are acceptable:

# 1 PETE (Polyethylene Terephthalate):

PETE, a commonly recycled household plastic material, represents approximately 30 percent of the plastic bottle market and is used to package a wide variety of food and beverage products such as soft drinks, juices, edible oils, liquor and peanut butter. PETE is valued for its clarity, toughness, and ability to resist permeation by carbon dioxide

# 2 HDPE (High-Density Polyethylene):

HDPE is characterized by its rigidity, low cost, ease of forming, and resistance to breakage. It is used to bottle milk, water, juices, bleach, detergents, and motor oil. (NOTE that motor oil containers are not acceptable in your blue box because of the oil contamination. They should be returned at your local hazardous waste day along with your used oil.)

# 4 LDPE (Low-Density Polyethylene)

LDPE is widely used in applications requiring clarity and processing ease. Its most common use is as film for grocery sacks.

How to Prepare Material:

Plastic bottles should be rinsed about with lids removed. Place this material loose in your blue box for collection.

What Happens after the Material Leaves your Blue Box?

Once the driver has collected the material from your blue box it is sorted into various compartments on the collection truck and brought back to the Bluewater plant in Huron Park for further sorting and processing.

The container line separates mixed containers into several commodities. When the containers collected from curbside are brought to the MRF, they are mixed and have no useful purpose. The association utilizes several innovative pieces of equipment, alongside dedicated material handlers, who are responsible for sorting all the containers collected from over 125,000 people.

One person (material handler) will look at the mix of containers to ensure that the mix is prepared for the equipment. This means that plastic bags are opened and removed, large items such as pails and broken blue boxes are removed, as well as any contaminants. Next, the containers are subjected to a magnet where steel containers are removed. Next a venturi based air classification system (vacuum) that separates light materials such as aluminum and plastic from heavy materials such as glass. A second person inspects the glass to ensure a contamination free end product. The light materials are mechanically screened to separate large from small pieces, essentially plastic from aluminum. The small fraction, primarily aluminum, is passed through an eddy current field which repeals aluminum and sends other small plastics back with the large plastics where two people (material handlers) separate them into three "resins" types: # 1 (PETE), #2 (HDPE), and mixed tubs and lids.

What Happens after the Material Leaves Bluewater?

After the material leaves the Bluewater MRF it is taken to a re-manufacturing plant which shreds the material. It is difficult to remove contaminants due to the small opening found on many products. By shredding the plastic first, the recyclable material is easier to wash. Further separation can occur during the cleaning stage. Lighter plastic flakes are dried then ground finer. Finally, plastic is extruded into new products or into pellets.

Recycled plastics become insulation for coats, sleeping bags and similar applications. Some oil jugs are made from re-manufactured High Density Polyethylene (HDPE). Bleach bottles, brush bristles, carpet backing, rope, trays and automobile bumpers all can be made from recycled plastic. Used food and beverage containers are not converted to new versions of the same product because minute traces of contaminants may be persistent in recycled plastic. For safety reasons, the plastic used to hold what we drink and eat is always new.

End Products

# 1 PETE

These bottles are recycled into fibrefill for sleeping bags, parkas, twine, rope, carpet and carpet backing, sign posts, park benches and an array of other applications as well.

PETE can be combined with virgin polyester to produce a fabric called Polartec, for use in high performance outdoor fleece and velour products or T-shirts.

Nissan Motor Company is now using recycled PETE bottle scrap to make dashboard insulators, the sound absorbing mats attached to the back of dashboards. The insulators utilize recycled resin produced by Mitsubishi Chemical Corp.

#2 HDPE:

HDPE is used in the production of bottles, plastic sheeting, pipes, blue boxes, garbage containers and similar rigid plastic products.

HDPE is also used in the production of drain pipes, plastic bags, flower boxes, clothes pins, car bumpers, "plastic lumber", the backing on carpets.

# 4 LDPE

When recycled, LDPE can be used to make most of the same products that can be made from virgin LDPE.

Questions and Answers?

Plastic Tubs 

Plastic tubs are made of either polypropylene (PP) or high density polyethylene (HDPE). Polypropylene is used to make margarine and yogurt tubs. It is good to use in these products because it can withstand high temperatures (making it a good choice for food packaging requiring sterilizing), and has a low density, which means more containers can be made per kilogram of plastic.

HDPE is used in packaging when products require freezing such as ice cream. This is because HDPE does not become brittle until temperatures are as low as -120 degrees celcius, while PP will become brittle at -8 degrees.

Recycled plastic tubs are used to make auto parts, patio furniture, indoor and outdoor carpeting, crates and boxes, measuring cups, apparel, toothbrushes and hairbrushes.

Plastic tubs cannot generally be recycled directly into new plastic tubs in direct contact with food because of concerns that the containers may have been used for other applications (ex. storage of pesticides).

Once collected, tubs may be ground into flakes, washed, dried and extruded into pellets from which new products may be formed. 

Identifying Plastic Waste 

In order to determine whether a plastic waste can be reused, it is important to know what type of polymer the material consists of. This is not always easy to ascertain immediately. Most consumer packaging now uses the standard SPI classification symbols consisting of a number between 1 and 7 surrounded by 3 arrows in a triangular pattern. These numbers identify the type of polymer that has been used to make the container. The polymer types are as follows:

Many industrial plastic waste streams may not have an SPI symbol conveniently stamped onto it and so this very simple approach of reading the label cannot be used to identify the type of polymer. In 1989, Dow Chemical Company published a one page guide to identifying rigid plastic containers. They produced a table that described the results of two very simple tests and three visual or tactile observations that would help to identify the type of polymer used. The tests involve a glass of water to determine whether a small piece of the polymer floats or sinks and the match to determine whether the materials burns or not, and if it does, how does it behave.

This is by no means an exhaustive or comprehensive method of determining polymer types. It does not address the polymers such as nylon engineering plastics or mixed polymer materials. It is, however, a very cheap and easy way of initially screening for these very extensively used polymers in both industrial and consumer products. Even this partial or tentative identification will helpthe waste exchanges to help you to find a potential user for your material. Once interest is established, then it becomes more worthwhile to consider the costlier analysis that will be required to confirm the type of material.

Table extracts from Dow Chemical Company fact sheet "Identifying Rigid Plastic Containers" (January, 1989).

Use caution when striking the match and attempting to ignite the piece of plastic. Keep a glass of water handy to quickly extinguish the burning piece of plastic. Remember that burning plastic may drip. The hot droplets will burn flesh and can mar surfaces.

For more information, click here for another fact sheet.

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