GB752600A - Improvements in or relating to filter units, particularly for tobacco smoke - Google Patents

Abstract

752,600. Tobacco smoke filters. LORILLARD CO., P., and H. & V. SPECIALTIES CO., Inc. July 2, 1954 [July 13, 1953], No. 19501/54. Class 130. [Also in Group XXVIII] Filter units for cigars, cigarettes or pipes comprise a tubular sheath and a compressed mass of semifelted fibres arranged in a non- parallel heterogeneous fashion therein and having diameters, preferably uniform, between approximately two and approximately twenty-three microns and random lengths less than approximately two inches. The fibres may be secured together at their points of contact by a resinous binder. To produce cigarette filter tips, strands 13, 14, 15, Fig. 1, sub-divided from a web of fibres arranged as above are gathered into a roving in a thimble 17, which may have an internally roughened surface and be rotated, and pass to a former 20 where they are compressed before being enclosed in a . paper sheath 22 which is sealed at 26, the resulting filter rod being cut into multiple-length units by a knife 28. The fibres may be of about fourteen to twenty-three microns diameter, of cotton, cellulose acetate, acetate rayon, viscose, nylon, or mixtures thereof. Alternatively or additionally, fibres of glass or asbestos, or equivalent synthetic fibres of resins or cellulose or protein derivatives, having about three microns diameter, may be used. The binder may be applied by spraying it in liquid form on to the fibres before they are formed into the strands 13, 14, 15. The binder is preferably a thermosetting phenolic-formaldehyde resin suitably dissolved or slurried in water, and is set by heating, with prior drying if desired, before or after the strands are combined into the roving. Alternatively, a dry uncured binder is added, as by mixing powder or staple in the fibres prior to strand or roving formation, or,adding continuous filaments to the strands or roving. As shown, a curing heating zone 29 and a cooling zone 30 are provided, the latter being essential when a thermo-plastic binder is used. The heating. zone 29 may incorporate a highfrequency induction coil, a dielectric field or infra-red rays, and the cooling zone 30 a blast of air through refrigerating coils. Alternatively, heating may be applied to the cut-off multiplelength filter units, cooling being dispensed with. In lieu of a paper wrapper 22, cellophane or a sprayed coating of molten resin or a resin slurry or solution may be employed. Specifications 707,364 and 725,471 are referred to.