User-Friendly Innovation: Alpha-Technology

With alpha-technology, it's possible to produce installation foam without isocyanate-based curing. Alpha-installation foams crosslink via silanes, especially alpha-silanes – hence the name and α symbol. Silanes are hybrid silicon compounds that have proven their worth as binders and adhesion promoters in paints, coatings and adhesives. These are generally so-called γ-silanes. The closely related α-silanes have only been around for a few years. They differ from their γ counterparts by only a slight change in molecular structure. α-Silanes are 100 to 1,000 times more reactive than γ-silanes – which is also referred to as the α-effect.

The starting materials for alpha-installation foam are silane-terminated polymers whose molecular chains end with an α-silane group. During curing, the silane groups of the individual chains react with each other. The process is initiated by atmospheric humidity. Since there is no isocyanate involved,¹ no carbon dioxide is released. As a result, conventional foaming agents such as propane or butane must be added to the product.

The foam's curing process produces methanol. However, it has been proven that under normal conditions of use, the amounts generated are too low to pose a risk to the user. Good news for users: according to GHS and EU regulations, alpha-technology-
based installation foams are exempt from labeling requirements for hazardous substances, except for their flammable butane or propane propellants.

Wacker Chemie AG has a patented process for manufacturing α-silanes and markets them under GENIOSIL^®².

¹ Test Report SP Sweden No. F4 17365
² GENIOSIL^® is a registered trademark of Wacker Chemie AG.