Sustainable, flame retardant insulating materials for facades.


Demonstrators of insulating materials for facades produced from various renewable raw materials.
(© Fraunhofer LBF)

Building insulation materials are an essential component of modern construction for energy saving. Due to its diverse benefits, expanded polystyrene (EPS) has a large market share in this area. EPS is only approved if it has low flammability, which is achieved by adding a brominated polymer as a flame retardant. However, as fully mineral oil-based components, EPS insulation boards are not expedient in terms of a sustainable, resource-aware and environmentally-aware handling of raw materials. This is why sustainable alternatives have been developed at Fraunhofer LBF.

Insulation using natural materials

The task in the “OrganoPor” research project was to develop innovative, bio-based insulation materials which, like mineral oil-based polystyrene foam, are interesting for the mass market. The aim was to produce light boardtype components that could be used on building facades. Above all, reduced flammability properties and mass availability of the raw materials from normal agriculture and forestry products were in the foreground. In particular, care was taken to ensure that the raw materials used would not be in competition with food production, which is why residual and side streams were used.

Abb. 1: Schematische Darstellung des Herstellungsprozesses der OrganoPor-Materialien.
(© Fraunhofer LBF)

Abb. 2: Schematische Darstellung der Flammwidrigkeit der OrganoPorMaterialien.
(© Fraunhofer LBF)

Effective fire prevention using natural materials

Porous, bio-based materials with particle structure were coated with a water-based duromer resin containing flame retardant and then processed in hot pressing to make boards. The raw materials used in the process were e.g. cork or corn cob grist, sugar beet pulp, peanut shells, flax and rapeseed straw, wood chips or bark mulch. A waterborne, lignin-based resin was identified as a suitable resin binder, so that all organic components consist of renewable raw materials. The flame retardants used were environmentally friendly, halogen-free mineral-based substances. In the event of a fire, the flame-retardant resin becomes charred, thus ensuring that the insulating materials maintain their stability of form, protecting the embedded porous biomaterials against fire in the process.

Abb. 3: Schematische Darstellung der Flammwidrigkeit der OrganoPorMaterialien.
(© Fraunhofer LBF)

Industry partners for product development wanted

In terms of heat conductivity, density and flame-retardant properties, various materials arising from the project fulfill the requirements of an insulating material based on renewable raw materials. Although the density is far less than that of polystyrene boards, it is similar to that of other bio-based insulating materials. However, compared to these, the OrganoPor materials offer the advantage that they are available as stable board goods and also have the favorable characteristic of low combustibility and flammability at the same time. Thus, there is a good chance the may be a successful product on the insulating materials market. However, in order to achieve a product that is suitable for the market, further development steps are necessary. It is envisaged that these steps will be carried out in the form of a joint project with strong industry partners in good time.

Sponsors and partners

Dieses Projekt wurde gefördert vom Bundesministerium für Ernährung und Landwirtschaft über die Fachagentur nachwachsende Rohstoffe e. V. (FNR).