What Is Plastic, Anyway? Our Guide to Plastic, Plastic Packaging, and Eco-Friendly Materials

What Is Plastic, Anyway? Our Guide to Plastic, Plastic Packaging, and Eco-Friendly Materials

Posted By on Aug 7th 2023

What is plastic? The highlights

  • Briefly, plastic is a synthetic or semi-synthetic material made of polymers that can be molded into solid objects.
  • Plastic covers a wide range of materials, so classifying certain materials as plastic may be subjective.
  • Eco-friendly products, even those that contain plastic, should carry a small environmental footprint.

Plastic is bad.

We’ve heard this statement since we were young. Plastic is bad, and we need to do what we can to eliminate it from our daily lives.

This statement fails to mention what plastic is and why it’s so bad. Unfortunately, the answer to both questions is a bit complicated, so most of the time, we leave it at “plastic is bad,” without going into further detail.

The problem with this is that the term “plastic” covers a huge range of materials, some of which are replaceable by more eco-friendly materials, some of which are not. In fact, some plastic alternatives (like bio-PET) are touted as eco-friendly when, in reality, they are nearly the same material as PET or LDPE. In this way, the plastic-free movement can be a form of greenwashing.

The key to avoiding greenwashing is educating yourself so that you know exactly what is meant when someone refers to “plastic” and when non-plastic alternatives aren’t so eco-friendly. Don’t get us wrong; we are not defending plastic. However, we understand that the world of plastic is a complicated place, and simply saying, “Plastic is bad,” won’t paint the entire picture.

So, what exactly is plastic, and why is it a problem? Here’s our guide.

What is plastic: the short version

In simple terms, plastic is a synthetic or semi-synthetic material that’s made of polymers. This means it can be shaped and molded into anything you want. Additionally, it’s lightweight and durable, and it can be used in many ways, from sterile packaging to textiles. Most plastics are made from nonrenewable fossil fuels, but some modern plastics are made of renewable materials, like corn.

The definition of plastic: the long version

Because the term “plastic” covers a huge range of materials, the short definition doesn’t cut it. To fully understand the problems with plastic, we need to go into detail about the different types of plastic and where they come from.

Types of Plastic

Let’s narrow down the definition of plastic.

Broadest plastic definition: Plastics describe all polymers, including naturally occurring polymers such as shellac, tortoiseshell, cellulose, amber, and latex from tree sap. A polymer is a substance made of many repeating units.

Broad definition: Plastic is a material comprising a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be molded into solid objects. Plasticity is the general property of all materials which can deform irreversibly without breaking. In the class of moldable polymers, this occurs to such a degree that their actual name derives from this specific ability.

Narrow definition: Plastic is a term used to describe any synthetic polymer whose primary backbone is carbon (regardless of the raw materials being used to generate that carbon).

Narrowest definition: Plastic is a term used to describe any synthetic polymer generated from fossil fuels.

At first glance, the definitions don’t appear to vary much. But when analyzing specific materials, their differences become apparent and help us better understand what plastic is.

Polyethylene terephthalate (PET), Low-density polyethylene (LDPE), and High-density polyethylene (HDPE) are all examples of petroleum-derived, carbon-based polymers. These are clearly plastics and fit all definitions of plastic. These include items like plastic bags, plastic bottles, and other plastic containers.

Polylactic acid or polylactide (PLA) and bio-PET are all examples of plant-derived, carbon-based polymers. These would qualify as plastic based on the official scientific definitions above. But, we know that some people who aren’t as steeped in science only consider the narrowest definition and may see these as non-plastics because carbon is derived from a renewable resource.

Cellophane is a semi-synthetic material made from cellulose—a naturally occurring polymer. The first two definitions would consider it plastic, but the second two would not. Cellophane has some plastic-like properties (though it is not 100% waterproof), but it’s derived from wood and behaves a lot more like paper than plastic. If you burn it (don’t!), it will light up like paper does. If you fold it, it will stay folded (plastic wrap, however, would return to its original shape).

Latex or rubber are naturally occurring polymers. However, today, most rubber is vulcanized (a process by which plasticizers and other chemicals are combined in manufacturing). Some natural rubbers will biodegrade, albeit very slowly, so they cannot be composted. However, natural and synthetic rubber is typically elastic, unlike plastic. This elasticity means that it can be stretched to a point and then will return to its original shape, so it does not necessarily have the plasticity many feel is required for a material to be called plastic.

Silicone is often described as a plastic alternative, but based on the first two definitions above, it should be considered plastic. Instead of petroleum-based carbon, it is derived from silica (essentially sand). Sand is a non-renewable resource, and the process of creating silicone requires the addition of similar plasticizers that people worry about with more traditional plastics.

Defining plastic can be a little complicated. Even if plastic is technically biodegradable (like some natural rubbers) or is made from something other than petroleum (like silicone), it doesn’t necessarily mean it’s eco-friendly. Additionally, each type of plastic can be harmful in its own way. It’s important that those who are seeking a more eco-friendly lifestyle need to be aware of exactly which types of plastics they want to remove from their lives and which eco-friendly alternatives they want to pursue instead.

What plastic is, according to EcoEnclose

As a company specializing in eco-friendly packaging, we’ve had to look long and hard at plastics and plastic alternatives to determine our definition of plastic and how we want to address each type. Looking at specific materials, here’s what we define as plastic and what we do not.


  • Low-density polyethylene (LDPE), High-density polyethylene (HDPE), Polyethylene terephthalate (PET), Vinyl, PP, and Polystyrene. These are the most common types of plastic and are very clearly plastic materials.
  • Polylactic acid or polylactide (PLA), bio-PET, and most other plant-derived plastics. Even if these utilize plant-based inputs, they are still artificially produced and behave like petroleum-based plastics if left as litter.
  • Silicone. It is a synthetically made material that reacts with fossil-fuel-based hydrocarbons. This creates siloxane monomers that are bonded together (along with plasticizers) to create a silicone resin polymer. Silicone is more stable than some petroleum-based plastics and is, therefore, often a preferred safer choice in food ware over other plastics. However, it does exhibit the same end-of-life, non-biodegradability characteristics as other plastics.
  • Acrylic emulsion-based paint or adhesive contain plastic (as acrylic is a form of plastic). Many in the industry think acrylic emulsion adhesives are “plastic-free,” but we want to be more transparent about what the material contains. Paper-based packaging that uses these adhesives can typically still be composted because it represents a tiny percentage of the overall material. Double-check with your composting service first if you choose to compost these materials.


  • We do not consider cellophane a form of plastic as it does not exhibit many critical characteristics of plastic and biodegrades naturally.
  • We do not consider rubber a form of plastic, given that it does not exhibit many critical characteristics of plastic. Many types of rubber will biodegrade more rapidly than plastic, though still quite slowly, in a natural environment.

Why is plastic harmful to the environment?

Now that we’ve determined what plastic is, we must discuss why it’s bad. Plastic has become so ubiquitous because it’s incredibly useful. It’s lightweight, inexpensive, and in its different forms, it can be used in countless ways. That’s why, since 1950, over 8 billion tons of plastic has been produced. Unfortunately, only about 30% of this plastic is still in use. 12% has been incinerated, 9% has been recycled, and 79% has ended up in landfills and the environment.

The reason for this is that plastic is tough to get rid of. Even if it is recyclable (not all plastic), contamination can render the plastic unrecyclable, sending it straight to a landfill. Once in a landfill, plastic cannot biodegrade, which means that it will just break into smaller and smaller pieces, called microplastics. If a landfill is well managed, it should prevent these microplastics from leaking into the environment. Unfortunately, not all landfills are (especially those in countries with poor waste management regulations). The leakage of microplastics causes all sorts of issues, and they have even been detected in human breast milk. Although we do not yet know the health consequences of this discovery, if there are any, it’s still concerning.

Furthermore, because plastic is lightweight, it can easily catch the wind. Even if things like plastic packaging or plastic bags are thrown away, they might blow away and become litter.

It’s also common practice for some countries to export their plastic waste to other countries to be processed and recycled. Unfortunately, many of these countries already lack formal waste management systems and struggle to manage the plastic waste that they already have. As a result, these plastics often end up in mismanaged landfills, improperly incinerated, or littering vulnerable communities and waterways, eventually becoming marine plastic. As a result, even if you do your best to sort and dispose of your plastic correctly, it may still end up as litter thousands of miles away.

plastic waste in waterways

Plastic's main issues are its universal use and its inability to biodegrade. Because of these two things, vulnerable communities are drowning in plastic waste, ocean plastic is killing marine life and ecosystems, and microplastics are now finding their way into the human body. To solve this problem, we must limit our plastic use as much as possible.

Plastic-free is not the same as ecologically superior

As we talk about plastic waste and its substitutions, it’s important to note that just because something is plastic-free doesn’t mean that it’s ecologically superior. Yes, plastic waste must be minimized for the reasons above, but with any material, you must consider the entire lifecycle, from sourcing to disposal. Organic cotton, for example, is biodegradable and all-natural; however, it requires a lot of land and water to cultivate, resulting in a much larger environmental footprint associated with production than plastic. If an e-commerce company were to replace its plastic packaging with cotton bags, it wouldn’t be as eco-friendly as they might think.

While we attempt to create as many plastic-free products as possible, these statements are in no way intended to demonize any materials or promote others as more eco-friendly. For example, we believe LDPE and HDPE (plastics) are typically ecologically superior materials to cellophane (which we don’t consider plastic), as they require less energy to produce, create less pollution in manufacturing, and are more readily recyclable.

When you decide which packaging products to choose and when to opt for plastic-free alternatives versus when you might want to go for recycled plastic, you need to consider a few things. Here are some things you might ask yourself:

  • How likely are your customers to recycle their LDPE or HDPE packaging?
  • What is the environmental footprint associated with the production of packaging material?
  • Does the packaging material contain adhesives or other materials that might affect the recyclability of that packaging?
  • What is the end of life for this product? Can it be recycled? Will it biodegrade? Will it remain in the environment forever?
  • What values do my customers have, and how does my packaging align?

Plastic-free doesn’t always mean environmentally friendly. To be truly sustainable, you must consider all aspects of your  packaging’s lifecycle.

How we answer the question, "Is this plastic-free?"

Now that we know what plastic is and the different types of plastic, it becomes easier to answer the question, “Is this packaging plastic-free?” When we talk to those asking if something is “plastic-free,” they’re usually asking some combination of the following:

  • Is it a material that will not biodegrade?
  • Will it cause lasting harm to the oceans and lands if left as litter?
  • Is it a synthetically or artificially made polymer (even if derived from renewable resources) with chemicals or toxins that could leach and cause harm to people or the environment?
  • Is it made with petroleum?

With this in mind, we realize that rather than giving a “yes” or “no” answer to the question, the most helpful way we can respond is by being specific about what materials are included and whether or not (and why) we see them as plastic or non-plastic.

This approach may not always give companies the answer they want to hear. But we hope this level of transparency helps everyone make the right decisions for their packaging strategy and supports their customers to dispose of their mailers and boxes properly.

So, for example, we may get the question: Are your 100% Recycled Kraft Mailers plastic-free?

Our answer: The 100% Recycled Kraft Mailer is a paper mailer and, as such, is largely free of any plastic. Most people would consider this to be a plastic-free product.

It is important to note that this product's glue, adhesive, and release liners contain synthetic polymers. On the Kraft Mailer, the release is a small strip of silicone-lined paper, which we consider plastic, even though many others do not. The silicone-release liners should be landfilled and are neither recyclable nor compostable.

Glue is also required to form and seal the Kraft Mailer. This glue is a thermoplastic hot melt adhesive and, therefore, does contain plastic. Additionally, the seal of the mailer is an acrylic emulsion adhesive. Because there are such trace amounts of these polymer adhesives in the overall package, the mailer can still be composted at home or in facilities that accept paper, envelopes, pizza boxes, and other corrugated materials. However, we strongly recommend that these mailers be recycled.

Virtually all mailers on the market utilize hot melt glues, resin adhesives, and silicone-lined release liners. While finding “plastic-free” adhesives and release liners is nearly impossible today, we are actively working on R&D to develop non-plastic alternatives.

If you ask a question like this, we know you care deeply about your company’s environmental impact. It is our responsibility to answer you clearly and as accurately as we can with the knowledge and  framework we have.

Have more questions about what it means to go plastic-free with your packaging? Contact us - we’d love to answer any questions you have.