Reapor^® glass foam

Sintered open-pored inorganic foams - a contradiction?
Diverse demands from industry for fiber-free absorber materials for immission control have given rise to the development of new open-pored materials. As early as in the 1980s, a mineral-organic gypsum foam made from water, a prepolymer and FGD gypsum generated as a by-product from flue gas desulphurization (FGD) was developed. This material is now successfully used as a sound absorber in office partition wall systems.

In recent years, a process has been developed to produce non-combustible, inorganic foams (REAPOR®) with a defined, variable micro-pore and macro-pore structure. As a result, the properties of the foams can be adapted to an extremely wide range of requirements.

These lightweight materials are mechanically resilient, non-combustible, recyclable and easy to process. They also have a high sound absorption capacity, low thermal conductivity and exhibit good chemical resistance properties. By being able to design the pore structure of REAPOR® in a specific way, products such as broadband sound absorbers for fixed rail vehicle tracks or wall panels with good thermal insulation properties can be manufactured.

During the production process, inexpensive, lightweight silicate aggregates, e.g. expanded glass granulate from waste glass, are coated with a hydrous mixture that contains a sintering aid. Shapes can be formed from this mass using conventional molding processes (pressing, extrusion, etc.). After drying, the lightweight aggregates are sintered by liquid phase sintering in such a way that, in contrast to conventional sintering processes, both the microscopic and the macroscopic pore structure of the green bodies are retained. The formation of sinter necks between the lightweight aggregate granules results in high mechanical strength.