GB953364A - Tobacco smoke filter plug and method for production thereof - Google Patents

Abstract

953,364. Making tobacco smoke filters. PHILIP MORRIS Inc. March 13, 1961 [March 15, 1960], No. 9069/61. Heading A2C. A web 13, Fig. 2, of paper incorporating or carrying filtering granules, and a web 14 of porous, e.g. crepe, paper of greater tensile strength, are both fed from reels to be superimposed over a guide roller (not shown) before passing between driven corrugating rolls 16, 17, whose inter-tooth penetration is adjustable by bodily movement of the roll 17, and under a driven spreader roll 19 having right and left handed threads 19a, 19b, the consequently interdigitated webs then being formed into rod shape as they pass on one endless band through first and second garnitures and under a grooved pressure roll, and being enclosed in a paper wrapper as they pass with it on another endless band through a third garniture, past a glueing roller, and through a heated folder and a cooler to a cut-off knife sub-dividing the formed rod, e.g. into cigarette filter tips. The rod shape is achieved by first enclosing the web 13 by the web 14 with its edges turned in round those of the web 13, and then applying further compression to crumple the webs. The filtering granules may be of silica, alumina diatomaceous earth, cobalt or iron oxide, anion or cation exchange material, or, preferably, activated carbon or charcoal up to 50% by weight of the web 13, and which may be added to the web pulp in manufacture or adhered to the web surface. The web 13 may be from 0.005 to 0.015 inches thick and the granules have a size in the screen range of 25 to 300 mesh per linear inch. The web 14 may be impregnated with a chemical absorbent which does not de-activate the granules, e.g. silica gel. More than one web 14 may be used, and the webs may be laterally offset. Fig. 4 shows upper and lower webs 14 and an intermediate web 13.