If you have taken an interest in recycling or sustainability then it is likely you have wonder what plastic is made of, or even better you have found out what the Resin Identification Code is. The Resin Identification Code that is displayed on the front back or sides of plastic products. You might be wondering “what do these actually mean in terms of recyclability”? For most  American consumers and even some brands and institutions the recyclability, costs, health concerns, and function of each of the 7 types of plastic still remains somewhat mysterious. Most can discern the difference of two metals just based on looks, whereas in the case of plastic this would be nearly impossible to do. This is part of the reason RIC was implemented in the first place. To give you some context, the RIC was started in 1988 by the society of plastics as a way to create a consistent and uniform recycling effort from post-consumer waste streams and therefore create a financially interesting recycled plastic market.

Each of the 7 numbers within the chasing arrows symbol correlates to a specific type of plastic resin. The correlation is as follows; Polyethylene terephthalate or PETE/ PET (1), High Density Polyethylene or HDPE (2), Polyvinyl Chloride or PVC (3), Low Density Polyethylene or LDPE (4), Polypropylene (5), Polystyrene (6), the 7th category is reserved for other/miscellaneous plastics that don’t fit in these categories. All of these plastics have strengths and weaknesses and will be addressed in this article.

Whether you are a brand or a consumer, understanding the Resin Identification Code will help you make resin choices for your products or goods that are better for you and the planet we live on.

PET is a polyester that is commonly extruded and molded-in food packaging applications like water bottles and food containers. PET is remarkable in the fact that it is transparent, strong, lightweight, economical, shatterproof, non-reactive, and recognized a reputable material for food and pharmaceutical applications all over the world. Additionally, PET does not contain any BPA or have any known adverse health effects. Even after rigorous rounds of testing PET has still shown to have no adverse health effects. Nearly all curbside recycling programs accept PET too. PET is the most recycled plastic in existence, once washed it can be chemically treated and turned back into a PET resin with little chemical deviation from its original material.

PET shatters the notion that all plastic is bad for the earth too. Although it is derived from petroleum, recycled PET actually retains nearly 40% of the energy expenditure, meaning that energy is saved each and every use after its initial sourcing. PET is also super lightweight and uses less material than alternatives, resulting in major carbon emission reductions during shipments. Being that PET is so light and thin it is estimated that it only takes up 1% of US landfills. PET does not leach either, meaning that it doesn’t end up in the groundwater if left in a landfill. Overall PET is available globally and is a great option for consumers and brands alike looking for a sustainable packaging material that makes sense from a logistical standpoint.

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Plastics identified as (2) are made up of high-density polyethylene or HDPE for short. HDPE is used in both rigid and flexible packaging solutions. A good example of HDPE is a milk jug or detergent bottle. Like many other plastics, it is super lightweight, meaning that energy is saved when using HDPE as a substitute for glass. It can be picked up by most curbside recycling programs and repurposed into patio furniture, playground equipment, gas tanks, and so on.

Resin Identification Graphic

The number 3 on the Resin Identification Code is reserved for PVC plastics. PVC is very dense and has remarkable tensile strength and chemical resistance. Probably the most recognizable example of PVC is industrial piping that carries running water. It also accounts for nearly a third of plastic used in the healthcare industry. Unfortunately, PVC is extremely dangerous if disposed of improperly. PVC has been known to leach chloride and Phthalates into the water over time. On top of that, PVC, when burned, creates a hydrogen chloride gas, even 5 ounces of PVC when burned is enough to kill a human being in a room. For this reason, PVC is a major containment to material recovery centers. Overall PVC serves an important industrial role but requires more work to recycle compared other types of resin plastics that are currently available. In general, PVC is not an optimal choice for institutions looking to lessen their environmental impact.

Low-Density Polyethylene is super popular in flexible packaging solutions. LDPE is commonly used in foams because of its super low-density, this also gives it the ability to be impact resistant and lightweight. Unfortunately, LDPE like PVC is not always accepted by curbside recycling programs and because of its low density to volume ratio, it is much less attractive to recycling centers.

The 5th resin identified by the RIC is polypropylene. It has a uniquely slippery surface making it ideal for products that are vicious in nature. Because of that trait polypropylene is used commonly in ketchup and yogurt. This property yields less food waste, as the consumer will be able to use more of the product before discarding the packaging. Polypropylene is decently recyclable and can be recycled back into its original form, in fact, most water bottle caps are made from polypropylene and not PET, this is why there is some consumer debate on whether or not to separate those pieces.

Resin Identification Graphic

The 6th resin is known as polystyrene. This is typically what you would think of as styrofoam,  it is used for disposable food containers, packaging peanuts, and so forth. It is easily the most hated form of plastic, and for good reason. Polystyrene is not accepted by most curbside recycling programs since it is so incredibly inefficient to recycle due to its low specific gravity. What is “low specific gravity”? Shipping a truckload of styrofoam to a recycling center, will not balance out the carbon impact or cost of transporting it to a material recovery center. Polystyrene’s low specific gravity also makes it especially prone to improper disposal and many of the tiny pieces end up in our oceans and even inside of our bodies.

Resin Identification Graphic

The last number is reserved for misc plastics including Bio-plastics. This catch-all category is for anything that wasn’t mentioned above. Interestingly, the recyclability of this category will vary dramatically depending on location.

This is important to note because a Bioplastic is not something that will degrade naturally in your backyard or in a home composting pile. These bioplastics still require a large amount of heat from a commercial composting plant in order to actually compost. This seems to be a misconception among consumers and brands alike. Many of the number 7 plastics display some sort of eco logo, leading to the misconception that they are made from recycled material already, which is not the case either. To make matters worse, Bioplastics are much much harder to repurpose than PET or HDPE, simply because they are designed for one-time usage and then decomposition, so think carefully about what kind of initiatives you are promoting with the use of bioplastics.

To summarize, the impact of plastics in packaging is largely dependent on the types of plastics we choose to use. Sure, they have their downsides, as plastics are derived from petroleum and add to the depletion of that resource and they are unsightly. But considering the bigger picture, plastics versatility and weight savings ultimately save us valuable energy over the long term. So give plastics second chance knowing now that without them we would be using other heavier less versatile materials in their place.