Plastics

Processing Plastics for Recycling

When collecting and processing PETE and HDPE plastic bottles, several contamination issues need to be considered. These are incompatible resin types, dirt/trash, caps/pumps, hazardous products, and incompatible grades.

An example of incompatible types is PETE and PVC. Although both containers are similar in look, they are definitely not compatible. When PETE is being melted down for production of pellets or fiber, any PVC in the batch can cause major problems with equipment since PVC melts at a different temperature than PETE. Learn what comes in PVC containers and make sure they do not mix with PETE being baled. Examples of PVC containers may include translucent pharmaceutical bottles, imported mineral water bottles, salad dressing bottles and cooking oil bottles. Check the code on the bottom of the container. PVC bottles are marked with a "3".

Contamination such as dirt/trash and caps/lids/pumps are items that need to be monitored during the processing of plastics. Contact the buyer to see what contamination levels they can live with and work to keep it at our under that level. Often this is an educational process with the consumers who are recycling these products. They need to be taught what is acceptable and what needs to be thrown away. Depending on the facility, these contaminants will often be left behind on the conveyor after all other plastics are picked off. The exception would be when the caps/lids/pumps are not removed from the container prior to recycling which then requires the recycler to remove these items which slows down the process. Don't store baled plastics directly on the ground since dirt and rocks will lodge in the bales and become a contamination issue.

Contamination because of incompatible grades is generally limited to HDPE plastics. An example is HDPE milk jugs and HDPE ice cream containers. Both are marked HDPE on the bottom of the container, but are not compatible grades and should not be baled together. The reason is HDPE can be both blow molded into bottles and injection molded into tubs. The two resins are different in their melt flow index. This can get complicated so the easiest thing to remember is only accept plastic bottles and not plastic tubs. Incompatible grades can also apply to the color of the plastics depending on the end-use of the material. This color sorting can impact the price you'll receive for your plastic bales. PET is mostly clear, but there is more and more colored PETE coming on the market and the trend is for increasing amounts of colored PETE. HDPE comes in numerous colors. The highest grade of HDPE is the non-pigmented (opaque) plastic. It also brings the highest dollar value of the HDPE plastics. HDPE that is white, blue, green, red or any other color is considered pigmented HDPE and carries with it less value. Color sorting the materials will bring a higher value for the bale, while a mixed bale of sorted color is of least value. Check with the buyer before getting started.


PETE PLASTIC (#1) PROCESSING

PETE - Polyethylene Terephthalate

PETE bottles consist of soda and custom plastic bottles

This grade of plastic consists of:
    • clear and green soft drink bottles
    • clear and green liquor bottles
    • some cooking oil containers
    • some coffee containers
    • some small water containers

Bottles must be rinsed with caps removed
Approximately 25 cubic yards (16 gaylord boxes) of PET bottles will equal an 800 pound bale of plastics.

Bales must be:
    • clean and dry
    • secured with 10 gauge galvanized baling wire
    • stored out of the sunlight and weather
    • loaded, shipped, handled and stored maintaining integrity
    • dense (at least 10 lbs. per cubic foot)
    • a standard size
When loading tractor trailers for shipment remember:
    • to stack bales properly to facilitate unloading
    • to load 30,000 lbs., smaller loads with pre-approval
    • to note trailer number on Bill of Lading
    • truck driver must sign the B.O.L.
    • to inform buyer of the approximate load weight to avoid freight chargebacks
Unacceptable Bales

All bales of material must not exceed 2% contamination. Contamination in this case includes all of the following:
    • any PVC bottles
    • any other type of plastic (HDPE, LDPE, PP, PS)
    • other PET plastic that is not specified above, i.e. scoops, tubs, etc.
    • material that has deteriorated due to sunlight
    • dirt and mud
    • stones, grease and glass
    • excessive paper
    • free flowing moisture (i.e. motor oil, cooking oil, \
    • water, detergent, or any other liquid)
    • any bales that are unprocessable
    • bottles of hazardous material or residue
    • bottles that contained pesticides or herbicides
    • medical waste


HDPE PLASTIC (#2) - Natural Colored Bottle Processing

HDPE - High Density Polyethylene - Natural Colored Bottles

HDPE natural bottles consist of post consumer, blow molded, translucent bottles with necks.

This grade of plastic consists of:
    • milk containers (natural)
    • some juice containers
    • some water containers
Bottles should be rinsed with caps or closures removed.
Approximately 40 cubic yards (25 gaylord boxes) of HDPE bottles will equal an 800 pound bale of plastics.


Bales must be:
    • clean and dry
    • secured with 10 gauge galvanized baling wire
    • stored out of the sunlight and weather
    • loaded, shipped, handled and stored maintaining integrity
    • dense (at least 10 lbs. per cubic foot)
    • a standard size

When loading tractor trailers for shipment remember:
    • to stack bales properly to facilitate unloading
    • to load 30,000 lbs., smaller loads with pre-approval
    • to note trailer number on Bill of Lading
    • truck driver must sign the B.O.L.
    • to inform buyer of the approximate load weight to avoid freight chargebacks
Unacceptable Bales

All bales of material must not exceed 2% contamination. Contamination in this case includes all of the following:
    • any other type of plastic (PETE, PVC, LDPE, PP, PS)
    • other HDPE plastic that is not specified above, i.e. detergent bottles, tubs, etc.
    • material that has deteriorated due to sunlight
    • dirt and mud
    • stones, grease and glass
    • excessive paper
    • free flowing moisture (i.e. motor oil, cooking oil, water, detergent, or any other liquid)
    • any bales that are unprocessable
    • bottles of hazardous material or residue
    • bottles that contained pesticides or herbicides
    • medical waste


HDPE PLASTIC (#2) - Mixed Colored Bottle Processing

HDPE - High Density Polyethylene - Mixed Colored Bottles

HDPE pigmented bottles consist of post consumer, blow molded, bottles with necks.

This grade of plastic consists of:
    • detergent bottles
    • some juice containers
    • pigmented milk containers (yellow or white)
    • some shampoo bottles
    • well drained motor oil bottles

Bottles should be rinsed with caps or closures removed.

Bales must be:
    • clean and dry
    • secured with 10 gauge galvanized baling wire
    • stored out of the sunlight and weather
    • loaded, shipped, handled and stored maintaining integrity
    • dense (at least 10 lbs. per cubic foot)
    • a standard size

When loading tractor trailers for shipment remember:
    • to stack bales properly to facilitate unloading
    • to load 30,000 lbs., smaller loads with pre-approval
    • to note trailer number on Bill of Lading
    • truck driver must sign the B.O.L.
Unacceptable Bales

All bales of material must not exceed 2% contamination. Contamination in this case includes all of the following:
    • any other type of plastic (PETE, PVC, LDPE, PP, PS)
    • other HDPE plastic that is not specified above, i.e. tubs, etc.
    • material that has deteriorated due to sunlight
    • dirt and mud
    • stones, grease and glass
    • excessive paper
    • free flowing moisture (i.e. motor oil, cooking oil, water, detergent, or any other liquid)
    • any bales that are unprocessable
    • bottles of hazardous material or residue
    • bottles that contained pesticides or herbicides
    • medical waste

Equipment for Processing Plastics

Several pieces of equipment will be necessary for processing plastics. This equipment is as follows:
    • Plastic Perforator/Flattner - This piece of equipment will simultaneously perforate and flatten containers. This can be important since it will often reduce the time it takes to bale plastics and improves the integrity of the baled plastic. It improves the baled plastic because the bale no longer contains any appreciable amount of trapped air in the containers. This can be important on a hot day when those bottles that are not perforated begin to expand from the hot air trapped inside putting additional pressure on the bale wire. If sufficient size or quantity of bale wire is not used, the bottles can expand to the point that the bale breaks open.
    • Baler - PETE and HDPE bottles should be baled in a horizontal baler if all possible. Horizontal balers will do the best job and should be considered strongly if you can afford the cost of a horizontal baler. Vertical or downstroke balers can do the job but you'll need to look at the specifications on the baler very carefully. The stroke of the vertical baler must be of sufficient length to ensure proper compaction of the plastic bottles in order to get a sufficient bale weight. If a vertical baler must be used for plastics, acquire on that has at least 90,000 psi platen pressure to ensure plastic bales of 650 pounds or greater. A horizontal baler can easily provide bales in excess of 700 pounds or larger which is what brokers and end-users prefer.

    Several things to keep in mind while baling plastics are how much plastic is needed to make a bale, how much bale wire is needed per bale, where can baled plastics be stored and how much plastic is needed for a typical truck load.

    It takes 15 cubic yards of plastics to make a 700 pound bale. Typically, 22 gaylord boxes (3' X 3' X 4') of uncrushed plastic bottles will produce a 700 pound bale. These numbers will change some since PETE and HDPE are of a different weight.

    It will take a minimum of 6 bale wires per bale of plastic. The bale wire should be 10 gauge to reduce the chances of the wire breaking. Double up on 12 gauge wire if 10 gauge is unavailable.

    Plastic bottles will degrade while unprotected outside. The following is the maximum time to leave bales of plastics outside in the weather and sunlight:
      • PETE - 6 months
      • HDPE - 1 month
      • PVC - 6 months
      • LDPE - 1 month
      • PP - 1 month
      • PS - 6 months

    The typical truck load of plastics will be around 30,000 pounds. It is therefore important that the baler can produce bales of at least 600 pounds or greater due to the limited number of bales that can be placed on a tractor trailer. If additional capacity is needed, request for a 53 foot trailer. Density of bales is very critical. The target is 10 to 15 pounds per cubic foot.

Ask the Right Questions

The following is a suggested list of questions to ask the broker or end-user buying the baled plastics:
    • Which plastic resin does the market accept? If they say #1's does that mean soft drink bottles, custom bottles and jars? Does that mean only PETE bottles with necks? Does that mean just soft drink bottles? If #2's are accepted, does that include HDPE bottles and tubs? HDPE bottles with necks? Will they accept both natural and colored plastics - like those used for milk and laundry detergent? What about bottles that contain motor oil? Does the market accept other plastics? If so, which resins are accepted?
    • How should the material be prepared? Can plastic be accepted commingled with other materials? If not, can you mix the resins together or should they be separated? By resin type? By color?
    • In what form do they want their material? Will they take it loose? Do they want it baled? Will they accept it granulated? If they want it baled, do they have standard bale sizes and densities? If they accept it granulated, do they have any special quality or size requirements?
    • What is an acceptable quantity for shipment? Household loads, partial truckloads or full truckloads? Will the market accept truckloads with bales of different resins (as opposed to truckloads of just one resin)? Will they accept small or odd-sized bales?
    • Are there any special requirements? Should caps and pumps re removed? What about labels?
    • Who is responsible for transporting the material? Will the broker or end-user pick it up or does it have to be delivered?
    • What happens if a load is downgraded or rejected? What levels and types of contamination are acceptable? What change in price will occur? Who is responsible for the material and the cost of doing something with it? Can you send a representative sample of the resin to the broker or end-user beforehand?
    • What are the rates and terms of payment? How will prices and terms change over time? Is a contract required? Will the contract be short-term based on spot market prices or long-term based on a fixed price?
If you have any questions, comments or need assistance regarding the processing of plastics for recycling, contact the Recycling and Solid Waste Reduction Program staff at MDEQ.