NL8301145A - CIGARETTE FILTER. - Google Patents

Description

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Cigarette filter.

The invention relates to cigarette filters and provides a vented cigarette filter having a tobacco smoke filtering core, a core enclosing inner Jiuls, a tubular body of aerated material around the inner sleeve and an outer enclosure enclosing the tubular body, which provides for use thereby entering laterally from outside air into the tubular body, which system is such that in use most of the smoke stream flows through the core to the smoker's mouth and most of the through the outer casing aspirated ventilation air passes through the area between the inner sleeve and the outer casing to the smoker's mouth. This flow pattern is preferably substantially constant; 15 while smoking the cigarette.

The outer casing may be pierced and / or air-permeable to provide ventilation air passage therethrough. The outer casing may be the mouthpiece casing with which the filter 20 is incorporated into a filter cigarette, in which case it will usually consist of air-impermeable material with ventilation holes therethrough; the filter will then first be manufactured and supplied for filter cigarette production as a bar without an outer casing, and the present invention also includes these uncoated bars. The outer casing could instead be a casing which is applied during the manufacture of the filter and then extends only along the length of the filter; in such a case, the filter can be incorporated into a filter cigarette by means of a ring mouthpiece or a venting mouthpiece casing. The invention includes all these types of filter cigarettes.

Within the stated requirements of a filtering 8301145 i, -2- * core, an inner sleeve, a tubular body of air-permeable material and (at least in the final filter cigarette, if not the first filter produced) a ventilating outer shell various prior filter constructions and compositions are possible, while in use the intended limitation of at least a major part of the smoke stream to the inside of the inner sleeve and of at least a major part of the ventilating air stream to the outer side of the inner sleeve is reached, so that the smoke and ventilation air in the filter remain largely separated from each other and substantially mix with each other in the mouth of the smoker.

For example, the core, which is the major pathway for the smoke, may consist of any of a large number of tobacco smoke filtering materials. Preferably it consists of cellulose acetate wick, but it could for instance also consist of staple fibers, bonded or not, or elemental wick (of cellulose acetate or polyolefin, etc.), crepe paper or smoke-permeable cellular material.

The core may have a uniform construction and composition longitudinally, or may instead have a composite construction, for example, of individual plugs with different properties (eg, pressure drop or filter efficiency, etc.), and / or composition; the core may extend over all or only a portion of the length of the filter (for example, leave a hollow at one or at both ends), and if the core is an assembly of two or more plugs, side by side plugs abut or be spaced some distance apart. If the core extends only partially along the length of the filter, it may be necessary for the inner sleeve to have a low air permeability or to be air impermeable in order to achieve the desired smoke and ventilation air separation with filter in use. to ensure.

The inner sleeve is usually a sheath; 8301145 «· * -3- the core can resp. the individual core plugs may be preformed with or without a plug shell and then sheathed with this shell or the core may be formed and sheathed in a combined operation. The inner sleeve, if the core is of a suitable material (e.g., thermal or solvent-softenable filaments, fibers, or foam), may instead be replaced with a unitary one (e.g., thermally or solvent-fused) , skin of the 10 core? it will then usually be air-impermeable, although partially fused-permeable, fully-forming skins can be formed by a controlled supply of heat and / or solvent. Other shapes of the inner sleeve, for example an extrusion-molded or dried liquid coating, are possible.

The inner sleeve can be air or smoke-permeable or impermeable depending on the nature of the rest of the filter. If the filter is such that, in use, the smoke flow and ventilation air naturally tend to remain separate from one another, could the inner sleeve be either permeable or impermeable? on the other hand, if the smoke flow and ventilation air would tend to over-mix in the filter during use, the inner sleeve 25 should have low permeability or be impermeable to limit or prevent such mixing.

The inner sleeve could for example consist of paper, plastic or a metal film or foil or a laminate of such material - for example a paper / plastic / paper laminate. It is preferred that the inner sleeve and the tubular body bond or bond to each other to resist separation in the composite product. For example, if the tubular body is to be formed by 35 solvent-plasticized filaments or fibers ... ......

To collect around the core and the inner sleeve, the latter thus suitably consists of a material plasticized with this plasticizer, so that the sleeve and the tubular body adhere together as soon as they are put together are being brought? for example, in the case of a tubular body of plasticized (eg with triacetin) cellulose acetate filaments or fibers, the inner sleeve may suitably consist of a cellulose acetate film. The inner sleeve and the material of the tubular body can generally be adhered together with any adhesive which is applied to one or both of them before contacting each other. If the internal sleeve is to be air or smoke permeable, this may be achieved by the inherent permeability of the sleeve material and / or through penetrations or larger openings therethrough. As noted above, it may be necessary for the inner sleeve to be non-air and smoke permeable if the core extends only partially along the length of the filter, especially if it has a recess at one end or both ends of the filter.

The tubular body surrounding the inner sleeve 20 may also be made of a variety of air-permeable materials - for example, bonded or non-bonded staple fibers or elemental wick (of cellulose acetate or polyolefin, etc.) or an open cell plastic foam. In general, it will consist of a material with a greater inherent air permeability than the core (and / or be provided with grooves or passages) so that it provides a relatively small pressure drop, while the overall system is still such that in use the smoke stream is promoted to flow preferentially through the core and not through the tubular body.

The outer surface of the tubular body may be smooth or have one or more grooves extending in the longitudinal direction of the filter therein. such a groove or grooves can resp. may extend from one end to the other end of the tubular body or stop shortly before one end or both ends. Such grooves help reduce the pressure drop of the tubular body and promote that the ventilation air concentrates in the region between the sleeve and the outer casing. Preferably, at least a portion of the ventilation air directly through the outer casing to such a groove or grooves The surface of the groove or of each groove will generally be air permeable.

The invention is explained by way of example only with reference to the following description of preferred embodiments, which should be read together with the accompanying drawings, in which like reference numerals indicate like parts and in which

Figure 1 is a schematic, partly cut-away * perspective view of one filter and filter cigarette according to the invention, Figure 2 is a schematic cross-sectional view of another filter according to the invention, and

Figures 3,4 and 5 images are similar to that of Figure 1 of other filters and filter cigarettes according to the invention.

Figure 1 shows a filter cigarette, in which the filter has a smoke filtering core 2 of bonded cellulose acetate elemental thread wick, which is enveloped with an air impermeable plug casing 4, which is a paper / plastic / paper laminate. Surrounding the plug casing 4 is a tubular body 6 of air-permeable bonded cellulose acetate filament wick with grooves 8 in its surface, which extend partly from the nozzle end 6 to the other end of the filter.

The composite elements 4,6 according to the invention is attached to a sheathed tobacco rod 12 by means of a ventilating mouthpiece casing 10 to form a filter cigarette. The nozzle housing 10 consists of air-impermeable paper with a ring of ventilation holes 14, some of which open directly into the grooves 8.

The nature and dimensions of the components of the composite element and filter shown are such that when smoking the filter cigarette, the smoke stream 8301145-6 is forced to flow through the interior of the core 2, while the ventilation air is limited to the tubular body 6 and the grooves 8 thereof, so that smoke and ventilation air are only mixed in the mouth of the smoker.

Figure 2 shows another composite element 2,4,6 according to the invention, the core 2, the plug casing 4 and the tubular body consist of the same materials as described for figure 1. In this case the outer surface of the body 6, however, corrugated to provide a large number. grooves 8 extending longitudinally from only one end of the element. This element can be used in place of the element of Figure 1 to provide a filter cigarette with similar smoking properties.

In variations of the two embodiments described above, the grooves 8 may be omitted so that the tubular body has a smooth outer surface, as shown in Figure 3, or the grooves of the type of Figures 1 or 2 may extend the entire length of extend the tubular body, as in figure 4, provided that they are such (for instance in terms of size and number) that during use the major part nevertheless flows through the core 2. In the embodiment of Figure 3 (and in fact in all embodiments X, the plug casing 4 consists, if the tubular body 6 is made of plasticized cellulose acetate-eleter thread wick or staple fibers, suitably made of cellulose acetate film or foil so that they will stick together.

In other variations of the various embodiments shown, the plug casing 4 may have punctures or larger apertures therethrough, or be inherently air and smoke permeable, provided that the other components are such that core 2 will nevertheless provide the major path for the smoke and body 6 the most important way for the ventilation air; or may the core 2 terminate shortly before one or both ends of the filtering cages, in which case it will then usually be necessary for the plug casing.4 to be air impermeable to achieve the desired effect. 830 1 1 4 5 * Λ Ensure that most of the ventilation air is diverted from most of the smoke stream until they reach the smoker's mouth.

Instead, in modifications of the illustrated embodiments, the outer sheath 10 could extend only the length of the tubular body 6 and the resulting sheathed filter | with a wrapped tobacco rod may be connected by a ring nozzle or by a totally ventilating nozzle case; in both cases, but in particular in the latter case, the filter envelope surrounding the tubular body 6 could consist of an inherently air-permeable material. An example of grooves 8 along the entire length is shown in figure 5.

Filter elements and filter according to the invention can be made continuous by manufacturing the core in an endless rod shape and therefore continuously forming the inner sleeve and continuously transporting the core surrounded by the sleeve with a continuous supply of air-permeable material around it by a tube former to assemble the air-permeable material into a tubular body around the core provided with the sleeve. If necessary or desired, a ventilating plug casing may be continuously applied around the tubular body while or after the endless composite rod is resp. is formed. For possible wrapping in this manner, continuous or discontinuous longitudinal grooves or undulations may be formed in the periphery of the tubular body; if the grooves or undulations are endless, they can be made while the tubular body is being formed - for example, by using a tube former with a suitable circumferential contour? if they are discontinuous, they will generally be pressed into the surface of the tubular body after forming the composite rod. The continuously fabricated, whether or not grooved, sheathed or non-sheathed composite rod can then be cut transversely to separate finite lengths. The first 8301145 -8- cutting usually gives rise to bars of an even multiple (e.g. sixfold) of the length based on the length of the individual element / which is incorporated into a filter cigarette. For the production of the 5 filter cigarettes, a double-length element, if necessary cut from an initially produced longer (eg six-fold length) rod, is placed between a pair of enveloped tobacco rods so that the ends are in contact therewith, and by means of 10 a ring nozzle or a vent nozzle shell is connected and the resulting assembly is then cut through the filter at double length to obtain two ....... filter cigarettes. It will be appreciated that if, as in Figure 1, the separate filter element is asymmetric, in that it is grooved at one end and not at the other, the initially manufactured multi-length rod is instead symmetrical - smooth - will be at both ends, as in. the case of the shape shown in Figure 1. The invention includes the initially manufactured multi-length filter elements and filters from which the individual elements and filters can be cut and their manufacture.

Example

A filter, as shown in Figure 5, is 25 mm long and has a circumference of 24.7 mm.

The 5.3 mm diameter filter core 2 consists of a bonded frizzled cellulose acetate filament of 8 denier per filament, which filaments are bonded together at the contact sites by applying triacetin as a plasticizer to the wick before it is gathered and compacted to the rod shape; the core shows a pressure drop of 100 mm water column.

The sleeve 4 consists of an air-impermeable cellulose acetate film. - - · -. -

The tubular body 6 with the four grooves 8 circumferentially along its entire length consists of crimped cellulose acetate filament wick of 8301145-9 denier per elemental wire, which is bonded at the contact points by, as well as at the core pretreatment of the wick with triacetine as a plasticizer.

The plasticizer also causes the sleeve 4 to adhere to the core 2 and to the tubular body 6.

The outer casing 10 is a plug of high air permeability (300 K) paper which is applied as part of the filter production. The illustrated filter, which is composed of components 10, 2, 4, 6 and 10, is initially continuously manufactured and cut to finite lengths as it exits the filter manufacturing machine as above. described. The lengths initially cut are an even multiple (eg 100 mm) of the final individual filters; these can then be cut to double length (¢ 5.0 mm) for the production of filter cigarettes,! as described above? at this stage, the filters lying between double-length tobacco rods can be joined with the tobacco rods by means of a ring nozzle or a vented total nozzle casing, after which the double lengths are cut to obtain separate filter cigarettes.

The pressure drop mentioned herein is measured according to the conventional method recommended by CORESTA (Center de Cooperation pour les Recherches Scientifiques Relatives au Tabac).

An air permeability of nK Filtrona units hereby means an air permeability of η x 1000 30 ml / min / 10 cm / 100 iraii water column pressure., As determined by measuring the pressure "p" in mm water column, which is developed through a flow of 1050 ml of air per 2 minutes through 10 cm of the sheet, film or film and calculation from the equation: 35 air permeability = 1050 *

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8301145

Claims (10)

1. A cigarette filter element having a tobacco smoke filtering core, an inner sleeve enclosing the core and a tubular body of air-permeable material around the inner sleeve, which system is such that when used with an external ventilating envelope, it tubular body, most of the smoke flows through the core to the smoker's mouth and most of the ventilation air drawn through the outer casing through the area between the inner sleeve and the outer casing to the smoker's mouth goes. . 2. Cigarette filter with a tobacco smoke filtering core, an inner sleeve enclosing the core, a tubular body of air-permeable material around the inner sleeve and a tubular body enclosing the tubular body. external casing, which in use provides a lateral entry therethrough of outside air into the tubular body, the system being such that in use most of the smoke stream passes through the core to the smoker's mouth and the majority of the ventilation air drawn in through the outer casing passes through the region between the inner casing and the outer casing to the smoker's mouth. 3. Filter cigarette, the filter of which consists of a tobacco smoke filtering core, a core enclosing the inner sleeve, a tubular body of air-permeable material around the inner sleeve and an outer sheath enclosing the tubular body and providing lateral entry during use. therefore from outside air 30 to the tubular body, which system is such that, in use, most of the smoke stream passes through the core to the smoker's mouth and most of the outside is drawn in ..... Ventilation air passes through the region, between the inner sleeve and the outer casing, to the smoker's mouth. Filter element, filter or filter cigarette according to claim 1, 2 or 3, characterized in that the internal 8301145 ': W22 <X. * • a -11- sleeve is air or smoke impermeable. Filtering agent, filter or filter cigarette according to claim 1, 2 or 3, characterized in that the inner sleeve is air or smoke-permeable. Filter element, filter or filter cigarette according to any one of the preceding claims, characterized in that the tubular body and the inner sleeve adhere or are adhered to each other. Filter element, filter or filter cigarette 10 according to any one of the preceding claims, characterized in that the tubular body has at least one longitudinal groove or channel, which extends at least partly along the length of the tubular body. Filter according to claim 2 or according to claim 2 in combination with any one of claims 4-7, characterized in that the outer casing extends only over the length of the tubular body. Filter cigarette characterized by a filter according to claim 8, which is received by means of a ring mouthpiece 20 or a ventilating mouthpiece casing. Filter cigarette according to claim 3 or claim 3 in combination with any one of claims 4-7, characterized in that the outer casing is a ventilating mouthpiece casing, by means of which the filter is incorporated in the filter cigarette. ______ '-m 8301145