GB1257360A - - Google Patents

Abstract

1,257,360. Smoking product. PHILIP MORRIS Inc. 9 May, 1969 [10 May, 1968], No. 23867/69. Heading A2C. In a smoking product, such as a cigarette, comprising tobacco enclosed in a combustible wrapper, perforations in the wrapper are closed by a non-toxic water-soluble coating material which is affected by moisture when the product is smoked to allow dilution of the smoke by ingress of air through the perforations. The perforations, which may be formed mechanically, or may be due to inherent porosity of the wrapper material, and the total area of which may correspond to 0.2 to 1.5% of the total area of the wrapper, may be omitted over a length of about 20mm. from one end of the product, i.e. the end remote from the filter in the case of filter cigarettes, and may be formed additionally in the wall of a filter associated with the product. The water soluble coating material, which may have a thickness of 3 to 60 microns and may be initially the same colour as the wrapper and change colour as it is affected to open the perforations, may be a natural material such as dextrin, starch or a gum, or a suitable synthetic polymer such as polyethylene glycol, polyvinyl alcohol, polyethylene oxide, polyacrylic acid or a salt thereof, or a polymer of polyvinylpyrrolidone. The coating material, which may have a bubble or cellular structure and may be applied by various coating methods depending on its viscosity, may incorporate a plasticizer and hygroscopic or other constituents, e.g. citric acid and sodium bicarbonate, to accelerate the opening of the perforations. Also a-filler such as fused alumina, titania, clay, talc &c or a flavouring agent may be incorporated. The coating may be applied before or after the wrapper is formed round the rod and may be localized over the perforations.