High-Density Polyethylene, commonly known as HDPE, is a robust and widely used thermoplastic polymer. It is identified by the Resin Identification Code (RIC) #2, which is typically molded into the plastic product. This material is known for its strength, durability, and resistance to chemicals, making it suitable for a variety of packaging applications. HDPE is one of the most frequently and successfully recycled plastics globally, accepted in the vast majority of municipal recycling programs.
Recognizing Products Made of HDPE
The simplest method for consumers to confirm an item is made of HDPE is by locating the triangular chasing arrows symbol, known as the Resin Identification Code (RIC). This symbol contains the number “2” in its center to designate High-Density Polyethylene. This code is usually embossed on the bottom or side of the container. While the chasing arrows suggest recyclability, the number inside is the definitive material identifier.
HDPE’s rigid form is common for many household containers due to its impact resistance and chemical stability. Products frequently made from this polymer include opaque milk jugs, liquid laundry detergent bottles, shampoo and conditioner containers, motor oil containers, and certain plastic food storage tubs. The material’s opaque or translucent appearance distinguishes it from the clear appearance of PET plastic.
How to Prepare HDPE for Recycling
Proper preparation is necessary to ensure that collected HDPE containers can be processed efficiently into new raw materials. The most important step is to rinse out all residual contents from the container. Contamination from these residues is a major issue in recycling, as it can reduce the quality of the recycled plastic resin and potentially ruin an entire batch.
After emptying and rinsing, instructions for handling the cap or lid vary. If the cap is also marked with the #2 symbol, it should be screwed back onto the container. This prevents the smaller cap from falling through sorting screens at the material recovery facility, while its attachment to the larger container ensures it is properly captured and sent through the HDPE processing line.
If the cap is a different type of plastic, such as polypropylene (#5), it should be removed and discarded, as mixing different resin types disrupts the recycling process. Consumers can crush or flatten rigid HDPE jugs and bottles before placing them in the recycling bin. This saves space in the collection truck, increasing hauling efficiency and reducing transportation costs. Labels and residue adhesive do not typically need to be removed, as the industrial washing process separates them from the plastic flakes.
Forms of HDPE Not Accepted in Curbside Programs
While rigid HDPE containers are widely accepted, flexible and bulky items made from the same plastic often require alternative disposal methods. Plastic films and bags, even if they are made from HDPE, should not be placed in curbside bins. The flexible nature of these materials causes them to wrap around the rotating gears and belts of automated sorting machinery, leading to frequent shutdowns and costly repairs at the material recovery facility.
These “tanglers” can often be recycled by taking them to designated drop-off locations, such as those found at many grocery stores and retail chains. Bulky items like five-gallon buckets, large storage totes, or plastic children’s toys may also be made of HDPE, but their size presents a challenge for standard automated sorting equipment. These large items may require drop-off at a specialized recycling center or a municipal transfer station.
Furthermore, heavily contaminated HDPE items that cannot be easily cleaned, or those containing hazardous residues, are typically rejected. Some recycling facilities may also reject plastic with certain dark pigments, such as black, because the optical sorting sensors used to identify and separate plastic types based on color and material density may not be able to reliably detect them. Consequently, all items must be clean and meet the size constraints of the local collection system to be successfully processed.