Expanded Polypropylene (EPP) is a highly versatile closed-cell bead foam that provides a unique range of properties, including outstanding energy absorption, multiple impact resistance, thermal insulation, buoyancy, water and chemical resistance, exceptionally high strength to weight ratio and 100% recyclability. EPP can be made in a wide range of densities, from 15 to 200 grams per litre, which are transformed by moulding into densities ranging from 18 to 260 grams per litre. Individual beads are fused into final product form by the steamchest moulding process resulting in a strong and lightweight shape.
Expanded Polypropylene (EPP)
The manufacturing process is complex, requiring both technical expertise and specialised custom equipment. Polypropylene resin is combined with other ingredients in a multi-step proprietary process. Under tightly controlled conditions, extruded pellets expand to become consistently shaped beads of expanded polypropylene foam. Other specialised manufacturing techniques may be employed to produce variations in the final product form.
EPP foam beads are then injected into molds. In many cases, cost-effective multi-cavity aluminum molds are used. Pressure and steam heat fuse the beads into a finished shape. The finished EPP foam part becomes a key component in sub-assemblies incorporated in the original equipment manufacturer’s product.
Expanded Polypropylene (EPP) Applications
EPP is available in grades necessary for a wide range of applications, based on the technical requirements. High density grades are used where energy management is important, such as automotive bumpers and interior passenger safety components. Low density grades are used for packaging applications, and medium densities find applications in furniture and other consumer products.
Porous EPP is comprised of cylinder-shaped polypropylene beads, which adds air space between the beads in the final moulded form, which enhances beneficial acoustical insulating effects and reduces weight.
EPP is commonly coloured black for automotive applications, though is often found in white for packaging products. EPP is available from some suppliers in vibrant colours suitable for presentation-grade textured surface.
Low Emission grades minimise outgassing of VOCs for automotive interior parts. Anti-static, dissipative and conductive grades, typically used for special packaging requirements, are available.
EPP is widely utilised by automotive manufacturers because of its performance benefits for energy management, lightweight, enhanced functionality, durability and recyclability. Applications include seating, bumpers, stowage systems, door panels, pillars, floor levelers, parcel shelves, head rests, tool kits, sun visors and myriad filler parts.
