Common HDPE Questions: What Is HDPE? Is HDPE Recyclable?

High-density polyethylene (HDPE) is used in a wide variety of applications, from plastic milk containers to high school lockers. Despite its popularity, most people know very little about this versatile material.

In this post, we answer the most basic questions surrounding HDPE. That way you can have a better understanding of whether HDPE is right for your next project.

What Is HDPE?

HDPE is a durable thermoplastic material that resists dents, scratches, corrosion, graffiti, and mildew. It has a density that can range from 0.93-0.97 g/cm3 and a large strength-to-density ratio. HDPE also has little branching, which gives it stronger intermolecular forces and a higher tensile strength than LDPE (Low-Density Polyethylene).

Who Discovered HDPE?

Technically, Karl Ziegler of the Kaiser Wilhelm Institute (now known as the Max Planck Institute) invented HDPE in 1953. As a result, he received a Nobel Prize for chemistry in 1963. But the road to HDPE started much earlier, somewhere near the end of the 19th century.

It was German chemist Hans von Pachmann who first observed a precipitate while working with a form of methane in ether. This compound was later identified as polymethylene, which is closely related to polyethylene.

Thirty years after that discovery, an American chemist created a high-density residue when he subjected ethylene to a large amount of pressure. While experimenting with ethylene at high pressures, the solid form of polyethylene was finally created by British chemists in 1935. The next step was Karl Ziegler’s process of using catalysts and low pressure for creating high-density polyethylene. Ziegler-Natta catalysts are still the most commonly used catalysts in polyethylene production today.

What Is HDPE Made From?

HDPE is made from carbon and hydrogen atoms that have been joined together to form high molecular weight products. Methane gas is converted into ethylene, which is then turned into polyethylene by applying heat and pressure.

While this overly simplified explanation might make it sound like HDPE is easy to produce, it’s important to remember it took scientists more than 53 years to figure out just the right process. That means it takes a properly equipped facility and a certain level of expertise to manufacture high-quality HDPE materials.

Is HDPE Recyclable?

Absolutely. In fact, it’s one of the easiest plastic polymers to recycle and is accepted at recycling facilities around the globe. HDPE is classified as a #2 plastic.

Once at the recycling plant, HDPE plastics are shredded and melted into pellets. These plastic pellets can then be used to create new HDPE products, such as bathroom partitions and cutting boards.

At Scranton Products, all of our products are made with recycled materials. They’re also, themselves, 100% recyclable.

Where Can I Learn More About HDPE?

Scranton Products has years of experience manufacturing HDPE products. We offer a wide variety of helpful resources on our website, designed to teach you more about HDPE plastics, our brands, and how they can improve your facility.

Learn more about high-density polyethylene or check out one of the many free resources available on our website.