How Are Plastic Bags Made?

How Are Plastic Bags Made?

By AAA Polymer | Post Consumer Recycled Resin

Jan 07

Plastic bags are virtually everywhere and are a part of everyone’s daily life, but have you ever wondered “how are plastic bags made?” Most people are surprised to learn the highly technical and complicated process of making a plastic bag. 

Every year, approximately 1 trillion plastic bags are made — primarily because they are versatile and cheap. Most importantly, plastic bags can be recycled over and over to create valuable post-consumer recycled (PCR) resins, which can be turned into PCR can liners and a host of other products. Let’s take a closer look at how plastic bags are made as well as a cost-effective alternative to using virgin resins in plastic bag manufacturing.

1. Plastic Bag Manufacturing Starts with Raw Material Extraction

The first step of making plastic bags is to extract the raw material. This material — polyethylene —can be derived from either cracked natural gas or refined oil. Because these hydrocarbons are located below ground, they must be reached and extracted through the use of drilling wells. 

2. The Refinery 

This refined oil or cracked natural gas is then transmitted to a refinery. When at the refinery, petroleum is separated into varying densities. This allows the oil that is required for the manufacturing of plastics to be extracted. The gas or oil is pressurized and superheated to make sure pure polyethylene chains are isolated. It’s vital to isolate these chains so they can be polymerized to form resin pellets of pure plastic. 

Varying amounts of pressure and heat will be used to manufacture resin pellets of different densities, which may be used for anything ranging from plastic shopping bags to grocery bags. For instance, grocery bags are commonly made high-density polyethylene, which has a higher tensile strength than plastic films made from low density polyethylene (LDPE) or linear low density polyethylene (LLDPE). 

3. Plastic Film Extrusion

Plastic film extrusion is the process of manufacturing raw pellets. It involves superheating and pressurizing raw LDPE, HDPE, or LLDPE plastic pellets to create a consistent molten liquid. Once the liquid is created, the resin is forced into a circular die. Then the hot resin is blown outward or upward to create a thin, long balloon of very pliable plastic film. 

The plastic bubble cools as it further expands, and it encounters several rollers that stretch it into very thin sheets, which will be the bag walls. The sheets are then rolled onto two individual flat beds and moved into the printing machine. 

4. Completing the Plastic Bag Manufacturing Process

The last step starts with pressing the two printed sheets together to create the sides of the bag. The plastic can then be wound and cut to the most suitable size and shape based on the actual use or application for the bag. This is where additional customizations can be added, such as perforations.  

How Are Environmentally-Friendly Plastic Bags Made?

If you’re looking for environmentally-friendly plastic bag, AAA Polymer offers a full line of high quality post-consumer recycled (PCR) resin can liners. And the process of manufacturing PCR can liners is very similar to the process of manufacturing plastic bags from virgin resins. The key difference is with new plastic bags, you must go through the process of extraction and processing limited, raw materials. 

However, when you use PCR can liners, the plastic resin pellets are made from previously recycled plastics, which reduces the overall environmental impact. Most importantly, plastic bags made from PCR resins offer comparable strength and pricing as our standard can liner. 

Contact AAA Polymer for Holistic Plastic Bag & Recycling Solutions

Whether you’re looking to improve your brand image by implementing PCR content into your products, looking for the best commercial can liners, or simply looking to learn more about plastics and recycling; AAA Polymer can help. Since 1974, we’ve proudly helped countless businesses throughout the U.S. create viable and profitable solutions.

Contact AAA Polymer today. 

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