GB1255564A - Tobacco smoke filters - Google Patents

Abstract

1,255,564. Tobacco-smoke filters. NATIONAL PATENT DEVELOPMENT CORP. 27 Aug., 1969 [29 Aug., 1968], No. 42590/69. Heading A2C. [Also in Division C3] A tobacco-smoke filter comprises a substantially cylindrical charge of a hydrophylic polymeric compound, said polymeric compound being highly porous and having a high surface area and being a polymer of a hydroxy lower alkyl acrylate, a hydroxy lower alkyl methacrylate, a hydroxy lower alkoxy lower alkyl acrylate, a hydroxy lower alkoxy lower alkyl methacrylate, acrylamide, methacrylamide, methylol methacrylamide or diacetone acrylamide; the highly porous, high surface area characteristics being produced either by preparing the polymeric compound in the presence of a blowing agent to foam it, or freeze drying a mixture of the polymer and water. Many suitable monomers, foaming agents and free radical catalysts are specified. Ultra violet or gamma radiation may replace the catalyst. Preferably the polymer is crosslinked, and many suitable agents therefor are specified. The monomers may advantageously be copolymerized with an ethylenically unsaturated mono or polycarboxylic acid, or less preferably with a partial ester of an ethylenically unsaturated polycarboxylic acid, and many such comonomers are specified. The smokefiltering material may be used as a carrier for humectants such as glycerine, propylene glycol, ethylene glycol, sorbitol, mannitol or corn syrup, and may be impregnated with flavours such as menthol, peppermint, or natural or artificial tobacco flavour. In the examples, 2-hydroxy ethyl methacrylate was polymerized in bulk, together with ethylene glycol dimethacrylate as cross-linking agent or with itaconic acid as comonomer, using tertiary butyl peroctoate as catalyst and sodium bicarbonate as foaming agent, to produce a foamed polymer which was then pelleted and used as a tobacco-smoke filter material in a cigarette. The pelleted polymer was also used with the addition of a 50% aqueous glycerine mixture with and without the further addition of tobacco flavour or tobacco flavour plus menthol. In further examples, 2-hydroxy ethyl methacrylate was polymerized in aqueous solution, with and without ethylene glycol dimethacrylate, with ammonium persulphate as catalyst, using sodium bisulphite as foaming agent either alone or together with sodium bicarbonate and citric acid, and the resultant foam polymer that precipitated was then frozen and freeze dried and the dried product granulated and used as a tobacco-smoke filter. The filter may be employed in cigarettes, cigars, pipes &. alone or in combination with other filters such as activated carbon, plasticized cellulose acetate fibres, corrugated paper or polyethylene particles or fibers.