Use of EPP in lightweight construction
How can a material that is so robust be as light as a feather? The answer is quite simple and can almost be guessed based on the term particle foam: Expanded polypropylene is over 90% air!
The resulting potential for lightweight construction makes the universally usable material one of the most sought-after resources in all industries, in situations where it is important to keep weight as low as possible. This makes a lot of sense in the packaging sector, but also in the car and motorhome industry. While car drivers save fuel and costs by reducing the weight of their vehicles, in turn reducing the burden on the environment, owners of recreational vehicles also benefit from other decisive advantages: For example, if the weight of a caravan is below the magic limit of 3.5 tonnes, noticeable relief can be expected in terms of tolls and fees, speed limits and parking, and driving licence regulations.
EPP in the automotive industry
For more than 20 years now, the main use of expanded polypropylene has been in the automotive industry, which consumes around 75 per cent of the particle foam used in Europe. It’s not only the light weight that gives EPP a decisive advantage over conventional plastics. EPP also has a lot to offer in terms of sustainability: The plastic foam is extremely resistant and robust and can be used over long periods of time. If a moulded part is no longer needed, it can simply be recycled without any problems.
Components made from EPP plastic are used in many different places in the vehicle:
- EPP stands out under both static and dynamic loads thanks to its excellent energy absorption and impressive retraction behaviour – a really good starting point for safety-relevant parts in vehicle construction!
- EPP is also functionally safe within large temperature ranges. Oil and chemicals do not affect the material, either.
- Visible EPP parts on a vehicle, such as sun visors or trim elements, can be colour-matched to the existing design.
- In the field of electromobility, the innovative foam is also becoming increasingly important due to its thermal insulation properties.
Expanded polypropylene makes your vehicle safer, lighter and more environmentally friendly.
EPP impact absorbers – foam protects
In order to exploit two crucial properties of expanded polypropylene – firstly its excellent resilience and secondly its ability to absorb impact energy – car designers developed impact absorbers made of EPP. Installed in bumper systems, in the event of a collision the pressure is absorbed by the EPP moulding and the energy of the impact, which presses on the chassis, is reduced. Such protection pays off, especially in the case of “parking accidents”, i.e. low-speed collisions. Expensive chassis damage can be avoided as a result of this.
Expanded polypropylene also provides additional protection inside the car: Crash pads and other padding inserts made from EPP improve passenger protection. The good retraction behaviour of the foam proves its worth here. Furthermore, the low weight also has a positive effect on energy consumption: Compared to the PUR semi-rigid foams often used in car interiors, the particle foam offers a significant weight advantage with the same energy absorption properties. An adjustment of the padding values in line with the requirements is possible in view of the (almost) freely adjustable EPP density from 20 to 180 g/l.
Automotive series parts made from EPP – safety with an attractive design
EPP is used in the vehicle interior for the following parts, among others:
- Boot liners
- Filler pieces
- Battery covers
- Sun visors
- Knee bolsters
- Seat stiffeners
- Roof rails
- Rear window shelves
With the help of foils and fabrics, moulded EPP parts can be refined and turned into attractive visible parts, and adapted in line with the prevailing design. At the same time, expanded polypropylene also exhibits impressively high rigidity and good bonding capabilities with other materials. These properties mean that high-density EPP can also used as a construction element.
Composite materials using EPP are also interesting for the automotive sector. Sandwich structures offer high, specific bending stiffness with low material weight, as the stiff top layers are kept at a distance by a lightweight foam core. Due to the increasing demand for lightweight and, at the same time, stable structural elements, such sandwich structures are increasingly becoming the focus of current developments.
Electromobility and EPP – environmental protection made easy
Electromobility brings further potential for expanded polypropylene. The vehicle battery has to cope with both the energy demand of the engine and the temperature control of the passenger cell, which considerably reduces the range of the vehicle. To keep the energy consumption needed for cooling or heating low and to insulate the interior of the vehicle effectively, particle foams such as EPP can be helpful. The energy that can be saved in thermal management ultimately benefits the range of the electric vehicle.