Aerogel insulation material for the construction industry and lightweight design

In the construction sector, composite thermal insulation systems based on polystyrene or mineral wool are currently well established. Mineral insulating materials with the addition of aerogels are a promising alternative, as they have very low thermal conductivity, can be functionalized, modeled and manufactured in various shapes in the casting process. However, the manufacturing process for the thermal superinsulators is currently still very cost-intensive and possible in a high-priced batch process. The aim of the "Aerolight" project is to develop a cost-effective manufacturing process for aerogels and new formulations. Aerogels are thus to be made usable in various applications in the field of thermal insulation systems, lightweight concretes and sandwich elements for facades and roof elements.

In order to drive forward the energy transition and achieve the EU's climate protection targets, energy and resources must be saved. 75 percent of all buildings in the EU are not energy-efficient by today's standards. At the same time, flexible, functional and cost-effective materials for thermal insulation are currently lacking in the building sector. Aerogels open up new possibilities in the development of high-performance mineral thermal insulation materials.

Sustainable and recyclable

The fine structure of the aerogel firmly encloses air molecules, resulting in a unique insulating effect. The nanopores in the aerogel thereby restrict the heat-conducting air molecules in their freedom of movement to such an extent that no energy is transferred to other air molecules. The aerogel thus becomes a high-performance insulator with very low thermal conductivity, which leads to greater energy efficiency during the service life of the building or product fitted with it. The mineral-based insulating materials do not require any petroleum-based starting material. Since the silicate-based aerogel is mineral, it can be reused as an insulation material after a recycling process.

Aerogels have so far been produced on a silicate basis from aqueous or alcoholic solutions by gelation and subsequent drying processes. Fraunhofer UMSICHT, together with its industrial partner Proceram, developed a completely new manufacturing process for aerogels that combines various production steps with the help of supercritical CO₂ and thus significantly reduces production costs. The result: spherical particles with low particle density and good flowability. The technology used enables a modular design of the production plant and thus easy scalability of the process. The newly developed production process also saves on other educts such as chlorine-containing hydrophobing agents and mineral acids. The process was successfully transferred to pilot plant scale, and up-scaling to industrial scale is now being prepared. A pilot plant with a capacity of 5000 t/year is scheduled to go into operation in 2024 at the project partner Proceram. The process technology innovation will enable various sectors and in particular the construction industry to exploit the outstanding material properties of aerogels for mass products in the future.

Aerogel particles with a wide range of applications

The innovative insulating plaster with the addition of aerogels allows lower application thicknesses and jointless insulating layers, ideal, for example, for renovating old buildings to avoid thermal bridges. Further advantages lie in the material transport through the plaster, especially of moisture to the outside, in the longevity of the plasters, the low algae infestation and the fire resistance.

Furthermore, the researchers at Fraunhofer UMSICHT are optimizing the formulations of the aerogel particles, which allow a desired adjustment of the material properties. In this way, aerogel particles can be made usable as a versatile high-performance insulation material for further applications, for example in lightweight construction.

• PROCERAM GmbH & Co KG