GB824324A - Tobacco sheet material and method of forming - Google Patents

Abstract

Water-resistant tobacco sheet material contains between 0.5% and 33% by weight of a substantially water-insoluble galactomannan plant gum or gums, e.g. locust bean gum, guar gum, tara gum, honey locust bean gum or Kentucky coffee bean gum. The material may contain from 2% to 15% by weight of fillers, e.g. kaolin, fuller's earth and polysaccharides such as cellulosic preparations. Flavourings and food dyes may be incorporated, as may other gums such as karaya, arabic, acacia and tragacanth, and cellulose derivatives such as methyl cellulose, carboxymethyl cellulose and hydroxyethyl carboxymethyl cellulose, alginates and pectates. The carboxymethyl and hydroxyethyl ethers of galactomannan gums may also be used as the galactomannan gum constituent. Strengthening fibres, such as glassine paper, cigarette paper or flax pulps, and humectants such as glycerin and diethylene glycol may also be incorporated, as may glyoxal to increase water resistance. The moisture content of the material by weight should be between 8% and 24%, from 9% to 13% for cigarettes and 16% to 22% for cigar binders. Preferably dry-ground tobacco stems or leaves or tobacco dust is used to form the material by coating a layer of gum formulation on one or both sides, the composite sheet being dried and worked into tobacco filler strips or further formed by pressing, moulding or extruding; or a wet mixture or dry mixture subsequently wetted of the tobacco with the gum and other constituents may be formed into a sheet by moulding, calendering, spreading on a belt or extrusion. Where a gum layer is coated, this may be effected by first applying the layer over tobacco particles spread on a wetted film-forming surface and then coating the exposed gum surface with further tobacco particles; to effect easy removal of the composite sheet, the film-forming surface may be expanded by heat; before removal, the sheet is dried, optionally dyed on its exposed surface, and moistened; after removal it is optionally dyed on its other surface, and has its moisture content reduced and excess tobacco removed from both surfaces. Alternative methods involving coating are to apply tobacco particles to a gum layer, and fold the tobacco-free surfaces into contact and adhere them, or turn the layer over and coat with tobacco particles the tobacco-free surface, to which fresh adhesive is added if necessary. Combinations of the above coating methods may be used. Quantitative process examples are given. Specifications 727,886 and 727,903 are referred to.