Polypropylene Recycling: How to Recycle PP Guide

Is PP plastic recyclable? Yes, it is!

Wondering how to recycle polypropylene (PP) plastic to better control plastic’s impact on the environment? Keep reading!

Deciding what to do with each type of plastic at the end of its life can be confusing, but understanding the value of the plastic and whether it has been designed with recycling in mind is instrumental to resolving the global plastics crisis.

In this blog, Renegade Plastics provides the information you need to start recycling Renegade materials and other polypropylene-based products to reduce global plastic waste and contribute to a more circular economy.

Is Polypropylene Recyclable?

Polypropylene is represented by the number 5 symbol by the Association of Plastics Recyclers identification. This is the number you have likely seen inside the triangle with the chasing arrows symbol. However, just because a product has this symbol does not mean the product is recyclable. In fact, polypropylene is only one of three types of plastics that are widely recyclable in the United States. The other two are polyethylene terephthalate (PET, popularly used for beverage bottles) and high-density polyethylene (HDPE, opaque plastic commonly used for milk jugs).

However, like these other two plastics, the answer to ‘is it recyclable?’ is complicated. While these types of plastics can be recycled, most plastic products are not designed with recycling in mind. They are therefore often ‘downcycled’, sent to landfills, or increasingly used in ‘waste-to-energy’ plants (which is a fancy term for an incinerator with a steam turbine to inefficiently generate electricity). Fortunately, Renegade products have been designed to contribute to building a more circular plastics economy.

Once a Renegade product makes it to a recycling partner, it is often first washed and then mechanically ground into flakes that are then melted into pellets. The pellets are then used to make new PP products. Pelletized Renegade PP is high quality PP because it includes few additives and is not commingled with less recyclable types of plastic.

Recycling Renegade PP products offers a unique opportunity to extend the life of this versatile plastic as its second life can be continued as inputs to our own fabrics, packaging containers, toys, furniture, automotive parts, and more. If recycled properly, these products can take on additional lives in other forms. As newer recycling technologies become more widespread, like scaled chemical recycling, recycled polypropylene’s life can be further extended. This recycling economy formed around polypropylene decreases the amount of plastics that end up in landfills and reduces the amount of petrochemicals needed to make everyday products.

Why Is Polypropylene Recycling Important?

The UN estimates that of the seven billion tonnes of plastic waste generated globally, less than 10% is recycled. While industrial PP products, like Renegade fabrics, are widely recycled, many consumer products made from polypropylene, such as yogurt containers, and restaurant takeout containers, are not actually accepted by Material Sorting Facilities (MRF). These products are difficult to sort due to their variety of shapes, sizes, colors and addition of other, non-PP, materials that contaminate the PP recycling stream.

However, as the demand for recyclable and recycled products grows, polypropylene reprocessing is a natural area of growth for the waste sector. Recycling polypropylene will create less waste, reduce the need for more virgin material extraction, decrease the associated emissions of GHGs, protect biodiversity, and experience positive economic and social impacts.

Environmental Benefits of PP Recycling

While reducing environmental plastic pollution is the greatest benefit of proper plastic waste disposal, recycling can have numerous benefits that we do not see in our everyday lives.For example, according to Waste Management, recycling just one ton of plastic can save 5,774 kWh of energy, 16.3 barrels of oil, 98 million Btus of energy, and 30 cubic yards of landfill space!

Recycling PP:

• Extends the life of landfill sites and avoids burning plastics.
• Reduces the amount of non-renewable resources (petrochemicals) used in plastic manufacturing.
• It saves organizations money on disposal costs and reduces landfill fees, solid waste, polypropylene material, plastic products, and PP packaging.

Polypropylene Recycling Process — How Is PP Recycled?

While PP on its own is straightforward to recycle, many PP plastic products cannot be recycled through curbside programs because they contain non-compatible materials, like PET, or they are difficult to identify with optical sorting equipment, like black takeout containers from restaurants. Without first educating recyclers about Renegade fabrics, they may get mistaken for PVC or polyethylene fabrics, which would result in them being thrown out. Renegade has teamed up with a growing number of recycling partners who are excited to recycle our products. If there is not one in your area, contact us, and we’ll help you find one.

The basics of polypropylene plastic recycling process are as follows:

1. Collection

In municipal settings, the first stage of the recycling process is collection and transportation to a MRF. How individuals or businesses dispose of plastic waste dictates the way in which material is collected for recycling. Recycling Renegade products may require direct coordination with a polypropylene recycler due to the volume of the material being recycled or the fact that the recycler will want to keep Renegade fabrics separate from other materials to preserve the quality of the recycled resin.

2. Sorting and Cleaning

Polypropylene recycling involves separating the polymer from other plastics or materials. Additionally, many recyclers have pre-wash lines to remove dirt and other contaminants that can reduce the value of the recycled resin.

3. Shredding

Shredding polypropylene is a multi-step process that requires the use of specialized machinery. The process begins by feeding the PP material into a hopper, which is then fed into the cutting chamber of the shredder.

Inside the cutting chamber, the PP material is subjected to powerful knives or blades, which cut the PP into small pieces in a tearing or shearing action. The size and number of knives in the chamber depend on the size and type of the PP material.

4. Separation

Machines sort the plastic based on its attributes such as color, size, shape, melting point, and light absorption. Then the sorted plastic is placed into the relevant area for manufacturing
products based on their properties.

5. Compounding

The last stage in the polypropylene recycling process is compounding. This involves machines, such as extruders, that melt plastic particles at a high temperature. This creates pellets of plastic, which manufacturers use to make brand-new products.

Polypropylene Mechanical Recycling

Mechanical recycling is a process by which materials are recovered, separated, shredded, and then melted down for remolding into new products. The steps described above are for mechanical recycling of polypropylene.

This process helps to conserve resources and reduces the amount of waste going into landfills. Mechanical recycling does not involve any chemical changes to the material and does not require the use of hazardous chemicals.

Mechanical polypropylene recycling produces post-consumer resin that can be used for carpets, fabric, plastic lumber, and even items like car parts and batteries.

Mechanical recycling is currently the least energy-intensive solution to plastic waste management, and therefore has the lowest carbon footprint. However, the quality of mechanically recycled polypropylene resin may not be optimal for certain products.

Polypropylene Chemical Recycling

Chemical recycling of polypropylene is in the nascent stages of implementation. It works by breaking down the polymer into its constituent monomers and refining them into pure polypropylene. This would allow for the production of recycled polypropylene that has similar properties to the direct-from-petroleum material.

By using chemical recycling, a wide range of shapes, sizes, and densities of polypropylene can be recovered, which makes it possible to manufacture a range of products, such as reusable plastic packaging, outdoor furniture, recycled carpeting, tote bags, plastic parts, shipping pallets, and other household items.

While often touted as a panacea to the global plastic recycling problem, chemical recycling at scale is in its early stages, requires a lot of energy and typically produces small volumes of recycled material; but it can yield higher-grade polypropylene that can be reused in applications that require higher quality.