Both expanded polypropylene (EPP) and expanded polystyrene (EPS) provide outstanding thermal insulation, energy absorption, multiple impact resistance, water and chemical resistance, and 100% recyclability.
The difference between EPP and EPS lies in the manufacturing process where the distinctive resin (polypropylene vs polystyrene) goes through a different process under tightly controlled conditions. Each process is briefly explained below.
Unique Properties of EPP
The EPP manufacturing process is complex. The polypropylene resin is combined with other ingredients and additives to form extruded pellets that are expanded to become consistently shaped beads of expanded polypropylene foam.
EPP foam beads are injected under pressure and heat into shaping moulds. Variations may exist depending on the final product form and specific client requirements. For example, air space added to the beads in the final moulded form enhances beneficial acoustical insulating effects and reduces weight.
EPP has unique applications in the automotive industry due to its exceptionally high strength-to-weight ratio, shock absorption, compressive strength and buoyancy. It is commonly coloured black for auto parts, but its textured surface can also take different colours for presentation-grade products. The standard white form is used for packaging.
Expanded Polystyrene (EPS) manufactured by the Isowall Group is fast becoming recognized as the insulation material of choice by specifiers of “Bills of Quantities”. This comes largely as a result of our technical knowledge backed up by years of experience in the building and construction industry.
Unique Properties of EPS
EPS manufacturing uses the polystyrene raw material, commonly spherical beads, in a thermoplastic process that expands and moulds the beads into the final product.
There is no extrusion involved, and the raw material is pre-conditioned, unlike EPP manufacturing. Specifically, the tiny spherical polystyrene beads are expanded to about 40 times their original size in a heating process.
In the moulding stage, the expanded beads take their final shape according to their application, which can be anything from large blocks to custom moulded designs. The large blocks can be sectioned to the required shape as panels or boards.
In its final form, the EPS is made up of 98% air, providing unique advantages in the building insulation and packaging industries, including lightweight-to-strength ratio, durability, superior thermal insulation and protection.
The distinct advantage of EPS consists of the large volume standard sized blocks and sheets used for insulation, and the availability of different grades, textures and custom sizes. Also, EPS is ideal for low volume packaging pieces where mould costs are not warranted.