Patent GB-752358-A (GB)
Title: Tobacco smoke filter material
Inventor: YARSLEY VICTOR EMMANUEL
IPC: A24D3/10
Filed: 1954-02-01
Abstract: Tobacco-smoke filter material in rod form, suitable for cutting into cigarette filter tips, is made by extruding into a hot or cold aqueous precipitating bath a composition comprising (a) a substantially water-insoluble cellulose acetate dissolved in a water-soluble solvent, e.g. acetone or glacial acetic acid; (b) a finely divided mineral or non-cellulosic synthetic fibrous material or a mixture thereof with one or more other finely divided fibrous materials; and (c) particles of a water-soluble solid, e.g. sodium chloride, sodium sulphate decahydrate or magnesium sulphate heptahydrate, so as to form a rod of fibres bonded together by the precipitated cellulose acetate, and containing pores formed by the leaching out of the particles of the water-soluble solid.  When acetone is used as solvent, the formed rod is removed from the precipitating bath and heated to expel residual acetone.  Natural, e.g. asbestos, or artificial, e.g. vitreous aluminium silicate, mineral fibrous materials may be used.  Suitable non-cellulosic synthetic fibrous materials are nylon and synthetic linear polyesters such as those derived from terephthalic acid and ethylene glycol. The other finely divided fibrous materials may include cotton, wool, viscose rayon or tissue paper shredded by mixing the composition prior to extrusion.  All the finely divided fibrous materials have a fibre length of less than 0.5 cm.  A screw-type extruder may be employed.  Quantitative process examples are given.ALSO:Tobacco smoke filter materials in rod form suitable for cutting into cigarette filter tips is made by extruding into a air hot or cold aqueous precipitating bath a composition comprising (a) a substantially water-insoluble cellulose acetate dissolved in a water-soluble solvent, e.g. acetone or glacial acetic acid, (b) a finely divided mineral or non-cellulosic synthetic fibrous material or a mixture thereof with one or more further finely divided fibrous materials and (c) particles of a water-soluble solid, e.g. sodium chloride, sodium sulphate decahydrate or magnesium sulphate heptahydrate, so as to form a rod of fibres bonded together by the precipitated cellulose acetate, and containing pores formed by leaching out of the particles of the water-soluble solid.  When acetone is used as solvent, the formed rod is removed from the precipitating bath and heated to expel residual acetone.  Natural, e.g. asbestos, or artificial, e.g. vitreous aluminium silicate, mineral fibrous materials may be used. Suitable non-cellulosic synthetic fibrous materials are nylon and synthetic linear polyesters such as those derived from terephthalic acid and ethylene glycol.  The further finely divided fibrous materials may include cotton, wool, viscose rayon or tissue paper shredded by mixing of the composition prior to extrusion.  All the finely divided fibrous materials have a fibre length of less than 0.5 cm.  A screw-type extruder may be employed.  Quantitative process examples are given.  The Registered Trade Mark "Fiberfrax" is mentioned.ALSO:Tobacco smoke filter material in rod form suitable for cutting into cigarette filter tips is made by extruding into a hot or cold aqueous precipitating bath a composition comprising (a) a substantially water-insoluble solvent, e.g. acetone or glacial acetic acid, (b) a finely divided mineral or non-cellulosic synthetic fibrous material or a mixture thereof with one or more further finely divided fibrous materials and (c) particles of a water-soluble solid, e.g. sodium chloride, sodium sulphate decahydrate or magnesium sulphate heptahydrate, so as to form a rod, of fibres bonded together by the precipitated cellulose acetate, and containing pores formed by leaching out of the particles of the water-soluble solid.  When acetone is used as solvent, the formed rod is removed from the precipitating bath and heated to expel residual acetone.  Natural, e.g. asbestos, or artificial, e.g. vitreous aluminium silicate, mineral fibrous materials may be used.  Suitable non-cellulosic synthetic fibrous materials are nylon and synthetic linear polyesters such as those derived from terephthalic acid and ethylene glycol. The further finely divided fibrous materials may include cotton, wool, viscose rayon or tissue paper shredded by mixing of the composition prior to extrusion.  All the finely divided fibrous materials have a fibre length of less than 0,5 cm.  A screw-type extruder may be employed.  Quantitative process examples are given. The Registered Trade Mark "Fiberfrax" is mentioned.