Verfahren zum Formen eines kontinuierlichen roehrenfoermigen Gegenstandes

1276117 Tobacco-smoke filters PHILIP MORRIS INC 4 Nov 1969 [3 Jan 1969] 54085/ 69 Heading A2C [Also in Divisions A5 B1 B5 and B6] A fluid pervious article, e.g. a filter for ventilated cigarettes is produced by continuous extruding (see Division B4-5) around a continuously fed fibrous tow 14, a sheath 12 e.g. of polyethylene, polypropylene, or cellulose acetate, which is drawn down e.g. to 0.005" to 0.015" thickness to adhere to and compressively enclose the tow 14 which it also grips within grooves 5 produced during the drawing down of the tube by the greater drawing down of the interior tube surface intermediate spaced regions 6 thereof which have been cooled by fluid jets e.g. of air or of inter-fibre bonding plasticiser, issuing from the die. The tow 14 preferably comprises longitudinally extending cellulose acetate filaments. It is fed to the extrusion die through a blooming and coating chamber, wherein the filaments are coated with inter-fibre bonding plasticiser e.g. triacetin, followed by compression and shaping through a cylindrical passage. The exterior surface of the sheath 12 comprises longitudinally extending flutes 16.