composite foil and plastic bag with coffee beans

Many of the products we buy come packaged in a blend of materials. Composites of paper or plastic with other materials can provide lightweight, durable packaging that protects products from breakage, moisture, and leakage. While such composite packaging may do a good job of protecting the products we purchase, it presents a recycling challenge.

Because composites are blends of different types of paper, plastics, metals, or wax, your local recycling program is unlikely to accept them in your curbside recycling bin or the local transfer station. That’s because the materials must first be separated before they can be recycled – and few materials recovery facilities (MRFs) have the capacity to do this. And because it is often not profitable, there’s little incentive.

To be an effective recycler, it’s important to understand the difference between, say, a milk jug made of HDPE (plastic #2) and a soy milk carton made of a composite of materials. The milk jug is a single type of plastic, making it easier to recycle. However, cartons are a composite of paper, plastic, and, sometimes, aluminum, so they require special processing. Unless you are sure that your recycling program accepts a type of composite packaging, putting it in your recycling bin disrupts recycling efficiency.

To start, take a look at some of the products you have at home and identify which ones have composite packaging

What Composites Are in Your Home?

Many common household items you use every day come in composite packaging. Chip bags, cereal bags, plastic and wax-coated papers, candy wrappers, pet food bags, coffee bags, packaging for cleaning and personal care products, dairy and nut milk cartons, and wrapping paper are just a few. Most food packaging is made of composites, including plastic-coated cardboard and bags. Packaging that holds a liquid is likely a composite material.

How To Identify Plastic Composites

Identifying composite plastic packaging materials can be challenging because they are made of multiple layers of different materials. However, there are a few ways to determine if a plastic-like packaging is a composite.

Look for multiple layers: Composite plastic packaging materials typically have two or more layers of different materials, such as plastic films, aluminum foil, or paper. If one side of the packaging is dull and the other is not it’s a composite material.

Check for a barrier layer: Composite plastic packaging often contains a barrier layer that helps to protect the contents from moisture, oxygen, and other external factors. The barrier layer is usually a thin layer of aluminum or another material, often #3 plastic (PVC), sandwiched between the different layers.

Check for a recycling symbol: Most plastic packaging is marked with a resin identification code that indicates the type of plastic used. Composite plastics sometimes carry a symbol with a number followed by several letters that indicate the different kinds of plastic used in the layers. They may also be marked with the #7 plastic code if they are a mix of two different types of plastic.

Check for stiffness: Plastic film composites are often stiffer than single-layer plastic films. The composite typically will not stretch like ordinary plastic film because it consists of multiple layers bonded to create a stronger and more durable material. If the material does not stretch, or has very little give to it, it’s probably a composite.

Check with the manufacturer: If container or packaging material provides no details about its material, you can contact the manufacturer for information. The manufacturer should be able to provide details about the materials used in the packaging.

Composite material recycling codes
Composite packaging may include a symbol similar to one of these, but they are not required.

How To Identify Composite Paper Packaging

Composite paper packaging materials are also made of multiple layers, making them more difficult to identify than single-layer paper packaging. However, here are a few ways to determine if a paper package is composite:

Look for a plastic coating: Composite paper packaging materials often have a thin layer of plastic coating applied to the paper to protect the contents from moisture and other external factors. The plastic coating can be visible or invisible depending on the package type. Tilting the paper to see if it’s slightly shiny is a good way to see if it has a thin layer of a different material on it if you aren’t sure. Paper is naturally dull while plastic is not.

Check the weight and stiffness: Composite paper packaging materials are usually heavier and stiffer than single-layer paper packaging. This is because the multiple layers of material are bonded together to create a stronger and more durable package.

Check for a metal layer: Some composite paper packages, such as those used for coffee or soup, may have a thin layer of metal foil sandwiched between the paper and the plastic coating, or it may be on the inside of the package. This metal layer helps to keep the contents hot and prevents them from leaking.

Again, if you are unsure, check with the manufacturer.

crushed composite paper and plastic juice box
Juice boxes like this are likely a composite of paper, plastic, and aluminum.

Is Composite Packaging Recyclable?

Putting composite packaging in your recycling bin can contaminate the remaining materials in the bin. For example, the moisture barrier in a chip bag is made with #3 plastic, which contains chlorides that can ruin the reusability of any #1, #2, #4, #5, and #6 plastics mixed with it during the recycling process.

In some cases, composite materials can be separated and processed for recycling. For example, some plastic-coated paper packaging can be recycled by separating the paper and plastic layers and processing them separately. Similarly, some composite plastic packaging can be recycled by separating the different types of plastic used in the layers and processing them individually. Separating these layers is not something people can do at home and therefore adds extra steps to the recycling process.

However, in many cases, composite materials are not recyclable or are difficult to recycle. This is particularly true for packaging that contains multiple materials, such as metalized film or laminated paper. These materials can be challenging to separate and process for recycling, so they often end up in landfills or incinerators. Depending on the item, they might get recycled but usually produce lower-quality materials with limited uses.

Potential Solutions for Composite Packaging

There are two solutions to the problem of composite packaging materials, and both will play a role in reducing household waste sent to landfills. Companies are developing new recycling technologies and processes that can handle composite materials more effectively. For example, some companies are exploring chemical recycling, which involves breaking down the materials at a molecular level and then using them to create new products. However, these technologies are still in the early stages of development and have yet to be widely adopted by the industry.

However, manufacturers can make the most significant changes by adopting standardized recyclable packaging materials that are easy to identify, sort, and recycle.

How You Can Help

By being able to identify which product packaging is a composite of different materials, you can avoid contaminating your recycling by putting the wrong things in the bin. Different types of beverage cartons, for example, are widely promoted as recyclable, but not all programs can process them. If you’re not sure your local recycling program accepts a certain type of composite packaging, contact them and ask. And if you can’t recycle them locally, you can help by contacting companies whose products you often buy and encouraging them to use packaging that can be easily recycled.

Watch for future recycling guides on how to recycle different types of products made of composite materials.