Mono-material packaging: Why is it more sustainable?

In the search for more sustainable packaging alternatives, the switch to mono-material packaging is an unquestionable trend today.

The development of more efficient and functional and protective mono-material alternatives has pushed this transformation to the front and is helping companies reach their sustainability goals.

In a time when recycling and joining truly sustainable models are necessary in order to comply with regulations and consumers’ changing preferences, companies are looking into mono-material solutions. 

What are the benefits of mono polymers, why are they more sustainable and what are their possibilities for developing packaging? Keep reading to find out.

What is a mono-material?

A mono-material is a product that is made of just one type of material. Thus, mono polymers are products that are made of a single type of polymer (for instance, just PE or just PP).

Mono materials are increasingly popular in many areas, including the packaging industry, as a report from Smithers Research confirms: mono-material film packs are expected to grow at a CAGR of 3.8%, reaching $71 Billion in 2025. This growth will be especially relevant in industries such as the food, confectionery, and pharmaceutical sectors. 

The growth of mono-material packaging responds to the main benefit: mono materials are easier to recycle than other products made of multiple plastics or mixed with other materials such as cardboard or glass.

Up until very recently, packaging has been made from different packaging materials and polymers, as companies prioritized versatility. However, recycling them isn’t easy or efficient: materials must be separated in order to follow their own recycling processes, or else the recycled plastic product will not present high quality.

On the contrary, a mono-material product uses less energy in the recycling process (as dividing materials is not necessary) and creates higher-quality recycled products.

Choosing mono materials and facilitating the recycling process also means companies can comply with urgent regulations. This includes the European Strategy for plastics, which is pushing companies to join circular-economy models and guarantee that all plastic packaging must be recyclable by 2030. 

Knauf circular presents an example of such programs, where a series of production sites and a picking-up program guarantees expanded polystyrene and expanded polypropylene are recycled. 

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Types of mono-materials used for packaging solutions


Polyethylene or PE is a thermoplastic polymer that today represents half of the global packaging market, according to the Smithers report mentioned above. Typically found in film packaging, its characteristics include:

  • Lightweight
  • Thermal insulation
  • Resists moisture
  • Durable
  • Flexible (not stiff)



Polypropylene (PP) is also a thermoplastic and widely used in the packaging industry because of its excellent features in terms of:

  • Lightweight
  • Thermal insulation
  • Resists moisture
  • Transparent


Polyethylene terephthalate (PET) is widely used for packaging food and beverages and is also lightweight and transparent. Developments in this material have allowed achieving full mono-material packaging made just from this mono polymer.


Polystyrene (PS) is a thermoplastic widely used as solid plastic and as a foam. Is commonly used in protective packaging for its lightness and flexibility, among other properties: 

  • Thermal and acoustic insulation
  • Resistance
  • 100% recyclability

Mono-material packaging designing process: the challenges

Mono materials are increasingly preferred because they allow companies to move towards their sustainability goals. 

However,  the transition to mono-material packaging also presents at least two challenges:

Functional limitations of the mono-material packaging

Companies have traditionally relied on designing packaging that includes several types of polymers. For instance, the case of flexible packaging typically presents three layers with differentiated functions: sealing, barrier, and printing.

Another example in the industry could be mixing an EPS cushion with a  cardboard tray to have shock absorption and drag protection. At Kauf Appliances we have developed a full PS alternative that keeps those properties with only one material.

Including mono-materials without an adequate re-designing process might compromise some of these functionalities, especially the barrier function and the mechanical properties.

However, new developments in mono materials mean that they’re increasingly overcoming these technical limitations and will soon be able to cover these needs.

Alternatives to counteract some of mono materials limitations include incorporating resin solutions as a coating. This eliminates the need to add additional materials or multiple layers and enhances the mono materials performance in terms of barrier protection.

Design limitations

Up until recently, choosing mono polymers was considered as compromising on design possibilities and aesthetics. On the other hand, multiple-layer packaging solutions were contemplated as an option that enabled many different design choices. 

Such a viewpoint saw the standardization of mono-material packaging as an issue. However, new plastic mono materials have evolved in terms of aesthetics and now also include customizable options such as plastic foam. 

At the same time, applying the principles of eco-design allows companies to experiment in incorporating new possibilities in tune with what customers want today.

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Mono-Material packaging: a recycler’s wish

To sum up, mono-material packaging represents the best alternative today for companies to be able to access sustainable, recyclable packaging solutions.  

At Knauf Appliances, we’ve worked for 40 years in the manufacture and supply of packaging using mono materials such as expanded polystyrene, PS-PE copolymers, expanded polypropylene, and other specialized foams. 

We are committed to generating sustainable, efficient packaging that helps companies comply with regulations and become sustainable, without compromising on packaging performance.

Want to learn more about the current mono-material packaging possibilities? Download our technical manual about expanded mono-material foam and discover how to use expanded foam for your business.


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