Expanded polypropylene(EPP):top material in the automotive industry

polipropileno expandido

Over the years, the automotive industry has developed a multitude of materials for the manufacture of parts, with expanded polypropylene being one of them. At Walter Pack, we want to tell you what polypropylene is, its properties, and its most common uses in the industry, taking advantage of our vast experience in the development of parts for the automotive sector…

What is expanded polypropylene and properties?

Expanded polypropylene is a type of expandable resin that is composed of 98% air, so it is extremely lightweight. It is also known for its great mechanical strength, which is why it is used in multiple applications in various industrial sectors.

EPP, developed in the 1970s, was the result of various research into new forms of polypropylene. It began to be used in Japan in 1982 to manufacture automotive products, and it is currently one of the industries that use it the most, due to its lightness, flexibility, and high impact absorption.

As for manufacturing, it is usually quite complex, as it depends on two important factors: technical knowledge and specialized equipment for it. The whole process requires several phases, under strictly controlled environmental conditions.

The procedure begins with the mixing of the polypropylene resin with other ingredients. The extruded granules are expanded until they become foamed polypropylene beads. Subsequently, the EPP beads are injected into multi-cavity molds, where the heat of the steam combined with the pressure causes these beads to fuse, taking the shape of the mold.

EPP is available in different grades depending on the application and technical requirements. High-density grades are used in applications where a high energy management is required, such as the case of automobile bumpers and interior safety elements for passengers.

There are also low-density grades, which are used for packaging applications. Finally, medium-density grades are used to manufacture furniture and various consumer items.

Properties of expanded polypropylene

As mentioned, EPP has multiple properties. The most important are:

·       It has great mechanical and chemical resistance.

·       It is resistant to compression.

·       It is resistant to moisture.

·       It has good insulating properties, both thermal and acoustic.

·       It is lightweight.

·       It is durable.

·       It has a high impact absorption.

Applications and benefits of polypropylene in the automotive industry

Due to all these properties, it is a material that can be used in various applications, with the construction of automobile parts being one of the most important. That is why we will explain the use of this material within this industry.

Interior elements

The first thing we must mention is its great energy absorption capacity and its lightness, two essential qualities for developing parts such as shock absorbers and air grilles. These components must be lightweight to optimize the weight of the car.

In the same way, thanks to its high impact absorption, EPP is used to manufacture other components for the car cabin, such as headrests, door seals, and other shock absorbers. This guarantees the safety of passengers in the event of an accident.

Floor components

EPP is also used to manufacture floor components. They are used to level the floor of the vehicle, thanks to the fact that it is a highly flexible material with which complex shapes can be designed.

Luggage compartment accessories

Similarly, it is used to make tool accessory kits, spare wheels for the luggage compartment, battery covers, among others. The reason for this is that it is a resistant material, so much so that it has enough strength to hold tools securely in the luggage compartment.


Also, EPP is used to make armrests, thanks to its strength and the fact that it does not suffer permanent deformation. This means that it returns to its previous shape when the pressure is stopped. At the same time, it offers stability and comfort.

Headrests and seat inserts

Similarly, polypropylene foam EPP is used to manufacture headrests. Headrests, being a passive safety component, have to be manufactured with excellent quality materials that provide the driver with the correct protection in the event of an accident.

Its great resistance to damage and great comfort make it perfect for this, not to mention that it is also used to manufacture car seat inserts, due to being a profitable and lightweight material.

At Walter Pack, we are always looking for materials that provide our customers with the best performance for their projects. That is why we use EPP to manufacture decorative and functional parts for sectors such as automotive or white goods, among others. We take advantage of its properties to create lightweight parts that can withstand wear and tear.