GB1251429A - - Google Patents

Abstract

1,251,429. Cigarettes. PHILIP MORRIS Inc. 9 May, 1969 [10 May, 1968], No. 23868/69. Heading A2C. A smoking product, e.g. a cigarette, comprising tobacco enclosed in a combustible wrapper has perforations in the wrapper closed by a non-toxic cellular filling material which is affected, e.g. melted, sublimated, disintegrated, or changed chemically, by a temperature between 35‹ and 250‹C so that the perforations are opened to admit air as the product is smoked. The perforations may correspond to 0.2% to 1.5% of the total area of the wrapper, and may be omitted over a length of about 20 mm. from one end of the product, i.e. the end remote from the filter in the case of filter cigarettes. The filling material, which may change colour when affected by heat, may be coated on the wrapper to a thickness of 3 to 60 microns before or after the wrapper is applied to the tobacco rod. Coating may be effected by printing, roll-coating, spraying or by knife or brush and is preferably such as to cover only the perforations. The filling material may be a water-in-oil emulsion of which the continuous phase is a polymer such as ethyl cellulose, polystyrene, polyvinyl chloride, a copolymer of vinyl chloride, polymethyl-methacrylate, nitrocellulose, cellulose acetate, cellulose acetate-butyrate, cellulose acetate-propionate or ethylene vinyl acetate, and the dispersed phase is aqueous. The continuous phase is mixed with a solvent that is insoluble in water, e.g. benzene, toluene, chloroform, &c., and the dispersion of the aqueous medium is aided by an emulsifier such as stearyl dimethyl, benzyl ammonium chloride or an aromatic polyglycol ether. A plasticizer such as tricresyl phosphate, dioctyl phthalate or castor oil may be added to lower the softening temperature. When a solvent with a relatively low evaporation rate such as toluene or xylene is used the evaporation of the aqueous dispersed phase may be retarded by the addition of e.g. salts such as sodium or lead acetate or polyvalent alcohols such as ethylene glycol or glycerol. Instead of an emulsion, the filling material may consist of two non-aqueous liquids in which the dispersed droplets do not appear until after application and evaporation of some of the solvent.