METHOD OF PREPARING OPEN-CELL FOAMED MATERIAL Russian patent published in 2006 - IPC C08J9/00 C08J9/16 C08J9/30 C08J9/35 A24D3/00 A24D3/04 

FIELD: polymer materials in tobacco industry.

SUBSTANCE: invention relates to foamed material constituted by cross-linked amino-formaldehyde polymer product suitable for filtration of tobacco smoke. Foamed material according to invention contains cavities and intermediate spaces located outside of cavities, said spaces being confined by walls consisted of cross-linked amino-formaldehyde polymer product optionally supplemented by additives. Average space dimension lies within 30 to 350 μm. Considerable portion of spaces have two or more perforations with average diameter within a range of 5 to 300 μm in their walls while considerable portion of perforations of neighbor spaces are arranged relative to each other in such a way as to form continuous nonlinear path. Foamed material is characterized by porosity at least 45 vol % and specific surface area 0.1 to 15 m²/g. Method of preparing of such foamed material comprises following stages: mixing air and foaming agent solution under pressure in mixing zone of injector filled with multiple inert mixing members; passing, under pressure, non-hardened foam from mixing zone and prepolymer solution into reaction zone of injector to form curable foam; and discharging foam and drying it in air. Use of such foamed mixture as cigarette filter allows content of toxic compounds such as resins and polycyclic aromatic compounds to be lowered.

EFFECT: enhanced tobacco smoke filtration capacity.

6 cl, 10 dwg, 6 tbl