Title: METHOD FOR PRODUCING FLAME-PROTECTED POLYURETHANE FOAMS HAVING LOW BULK DENSITIES

 Number/Link: WO2013174745  (German)

Applicant/Assignee: Bayer

Publication date: 28-11-2013

“Gist”: Low density flex foam is impregnated with water glass

Why it is interesting: A flexible slabstock foam with a density of about 15 kg/m³ or less is submerged in a solution of amorphous water-slouble silicate, preferably a  Na-silicate, then compressed in a roller mill and dried.  The resulting foam has a (much) higher density but also a much improved flame resistance.  In an example an 11.6 kg/m³ TDI slab foam resulted in a 27.3 kg/m³ density foam after impregnation and drying.  A simple and workable idea but I doubt if it is patentable.

Sodium silicate