MATERIALS AND APPLICATIONS
The Sacco beanbag by Zanotta. The filling is made of polystyrene beads.
Although less well known and less significant than the traditional applications— thermal insulation for the construction industry and packaging— expanded polystyrene can also be used in the furnishing and interior design sector to create new forms.
EPS: BOUNDLESS CREATIVITY
Italian technology plast / June-July 2026
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Although we are talking about a niche application, the particular properties of expanded polystyrene( EPS)— its lightness, versatility and strength— have made it a valuable resource for designers and creatives, allowing them to produce a wide variety of interior elements that reflect the trends of the past five decades.
A PIECE OF FURNITURE MADE POSSIBLE BY EPS Perhaps, it is the most well-known example of a piece of furniture using EPS, a designer’ s icon from the 1970s that remains popular even today. We‘ re talking about the Sacco beanbag by Zanotta, a deconstructed chair that welcomes the person who sits in it taking his / her shape and moulding itself to adapt to the body and posture. This object has so broken the mould and entered the collective imagination that in 2020 it won the coveted Golden Compass award, adding to the many design accolades it has received since its creation.
What makes this beanbag unique is its structure, consisting of a sack made of six slices of fabric sewn to a hexagonal base and a top piece narrower than the base. Inside this bag is a second, lighter fabric bag containing EPS beads that provide padding and support for the person sitting on it. The principle underlying the functionality of this comfortable and informal piece of furniture is the fluidity provided by numerous EPS beads, each just a few millimetres in diameter. These beads are the result of the pre-expansion of polystyrene. They appear as small white balls, typically ranging from 2 to 6 mm in diameter. Their unique feature is that each individual bead is 98 % air, enclosed in a closed-cell structure that provides elasticity: when compressed, they tend to return to their original shape. There are several reasons why EPS beads are an excellent filling material. First and foremost, their adaptive ergonomics: unlike a fixed seat, the beads move according to the pressure of the body,
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