A process for producing a cigarette filter material

Abstract

Abstract Filter materials for filtering aerosols, such as cigarette filters for filtering tobacco smoke, are provided comprising rigid polyurethane particles devoid of any cellular structure. Preferably the particles are granular and of jagged, spiny, cragged nature. The rigid polyurethane is produced from a polyol and a polyisocyanate. The particles are produced by first preparing a rigid polyurethane foam, preferably with the aid of a blowing agent, granulating the foam, treating the granules with hot water or steam to hydrolyze unreacted isocyanate and other free materials to render them inert, and then dried. Preferably, inorganic additives may be present during the preparation of the rigid polyurethane foam, such as the lower alkyl silicates, e.g., ethyl silicate, and water soluble salts of the acids of metals of groups VA and VIA of the Periodic Table, e.g., sodium tungstate. Inorganic additives may be added to the filter particles, such as an alkaline earth metal carbonate, silicate or hydroxide.

Inventors

• 👤 R Strickman

Bibliographic Details