Mediakit 2018


DuPonts PBT and TPE Enable Innovative Design for First Flexible Cantilever Chair

 |  Subj: Engineering products

Cantilever Chair

Ahead of the Royal College of Art graduation show, DuPont Performance Materials (DPM) and the industrial designer Frederic Rätsch announced a visual design concept of flexible seating in public spaces and a new chapter in design thinking which pushes the limits of DuPont Crastin polybutylene terephthalate (PBT) and Hytrel thermoplastic elastomer (TPC-ET) materials.

Flexible Seating in Public Space

Comfort, esthetics and robustness of chairs in public spaces and contract markets can seem to be contradicting attributes. To address this dilemma, industrial designer Frederic Rätsch and specialists from DuPont Performance Materials started working on the project Flexible Seating in Public Spaces in October 2016, initiated as his graduation project in Design Products at the Royal College of Art in London.

New Innovative Design

  • The vision was to create a chair by leaving the route of conventional commodity plastics, creating the first flexible cantilever chair with unique benefits in sitting and stacking while introducing a new design concept.
  • The fresh proposal takes advantage of the strong and tough DuPont Crastin PBT for structural firmness and the flexibility of thermoplastic elastomer Hytrel for enhanced softness, pleasant touch-and-feel of the seating and backrest surface.
  • The design concept had to weave in observations of sitting behavior, context and production technique.

Andreas Zöller Marketing and Innovation Leader EMEA, said:
It has been a fantastic journey to bring our world-class application development capabilities to this project. Bringing deep understanding of material properties, functional and aesthetic design concepts on one table has been energizing and enabled us to push the limits in our minds.

Aiming to design a cantilever chair  the most challenging category of a chair  would allow combining an outstanding design, extraordinary comfort and movement. Thus, the main theme is flexible seating, addressed in different scenarios: flexible in movement, flexible in context and flexible in sitting postures. So far only two cantilever chairs made structurally from plastic have been identified on the market and none of them is capable of providing the flexibility one would expect of a cantilever chair.


The context of the chair is public space, both indoors and outdoors of cafés, restaurants, canteens, museums, libraries, universities etc. Throughout the Double Cantilever Chair (DCC) is consciously designed with the research of the particular context, material, design history and sitting behavior in mind. In Frederics opinion it is essential that design does not become something arbitrary or stylized. Hence:

  • The chair is characterized by e.g. the ability to put it on a table for floor clean up, the needs for agile seating, the materials used and outdoor performance.
  • It resembles understanding of the materials and showcases them while pushing the performance plastics to their limits.
  • A contemporary and bold appearance has been considered continuously with the aim to underline the character and attitude of the chair.
  • Attitude is crucial in the way Frederic thinks of sustainability, which he approached for years and tackled lately in his MA dissertation.
  • Products need to be durable, produced in high quality and provide a strong character that allows the user to identify with it and therefore built a long lasting relationship.

Development Process

  • DCC achieves the comfort of upholstered furniture through the use of high performance plastics.
  • It features an elastic seat made of Hytrel that allows adaption to the body.
  • It is visually totally flat and solid, but therefore provides a surprising moment when actually being soft and flexible.
  • The Crastin PBT with its strength and stiff properties is an adequate material to support the seat shell, while still allowing some flex.
  • The design process was driven by a constant exchange between the computer and full-scale model making.
  • CAD models are used as a tool to record the process and allow FEA, stackability tests and arrangements in the chairs context.
  • While wire and cardboard models helped to define the design idea, further models in polystyrene foam or plywood enabled the basic seating comfort to be assessed.
  • In the final phase of the development the Institute of Plastic Processing (IKV) of the RWTH Aachen University, Germany, manufactured a full-scale prototype on their large 3D printing assets, using Hytrel for the seat shell to showcase the intended flexibility.

Nicolai Lammert, Institut für Kunststoffverarbeitung (IKV), RWTH Aachen, said:
The IKV is happy to have successfully contributed with its knowledge and large 3D printing assets in fused filament fabrication (FFF). Using that promising technology the making of a full-size 3D printed chair has been a challenge, due to its size, the use of DuPonts new engineering filaments and the time constraints. There was no room for production repetition, but these new filaments revealed to be low warpage and easy in the printing process.

Flexible Seating in public spaces is on display at the Royal College of Art graduation show from 24 June to 2 July 2017.

Source: SpecialChem

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