ES2970265B2 - Tobacco tar and toxic compound reducing filter manufacturing machine - Google Patents

Description

DESCRIPTION

TAR AND TAR REDUCING FILTER MANUFACTURING MACHINE

TOXIC COMPOUNDS IN TOBACCO

OBJECT OF THE INVENTION

The present invention may be included within the technical field of cigarette filters, particularly combined filters and machines and methods for manufacturing them. More specifically, the object of the invention relates to the machine for manufacturing a filter as a final product, where the resulting filter comprises a primary membrane of impermeable or semipermeable material intended to be in intimate contact with one end of a tobacco column, which is pierced by at least one hole, and said primary membrane is inseparably sealed with the classic fibrous membrane of traditional filters.

BACKGROUND OF THE INVENTION

Tobacco smoke contains more than 8000 chemical compounds [J.P. Schaller, D. Keller, L. Poget, P. Pratte, E. Kaelin, D. McHugh, G. Cudazzo, D. Smart, A.R. Tricker, L. Gautier, M. Yerly, R. Pires, S. Le Bouhellec, D. Ghoh, Hofer, I. García, E. Vanscheeuwijck, S. Maeder Evaluation of the Tobacco Heating System 2.2. Part 2: Chemical Composition, Genotoxicity, Cytotoxicity, and Physical Properties of the Aerosol, Regul. Toxicol. Pharmacol., (81) (2016), pp. S27-S47, DOI: 10.1016/j.yrtph.2016.10.001] and more continue to be identified as various studies are completed and more sensitive analytical equipment becomes available. Many of them, around 100 (Federal Register /Vol. 77, No. 64 /Tuesday, April 3, 2012), are considered toxic and/or carcinogenic. Therefore, tobacco consumption represents a major public health problem worldwide, but it also represents a significant business, which has generated an enormous conflict of sociological, political, economic, and scientific interests for many years. Thus, both tobacco companies and numerous researchers are developing interesting research aimed at reducing the toxicity of tobacco smoke, reducing the doses inhaled by smokers, developing new substitute products, and even legal restrictions on additives, emissions, and even their use.

Every component of cigarettes has been intensively studied, from paper to additives, tobacco to filters.

For example, the effect of paper permeability has been studied (“Effect of potassium inorganic and organic salts on the pyrolysis kinetics of cigarette paper” by Deqing Zao et al., (Journal of Analytical and Applied Pyrolysis, 102 (2013) 114-123). Self-extinguishing papers have been developed (e.g., that described in PCT/KR2009/003425).

Genetic modifications of tobacco have been studied to reduce the generation of nicotine and tar (WHO study group on tobacco product regulation, Report on the scientific basis of tobacco product regulations: Fifth report of a WHO group study, ISBN 9789224 1209892, 2015), as well as the use of additives or catalysts capable of reducing the emission of toxic products (Reduction of tobacco smoke components yield in commercial cigarette brands by addition of HUSY, NaY and Al-MCM-41 to the cigarette rod, A. Marcilla et al., Toxicology Reports (Open access), 2 (2015b) 152-164), or tobacco-specific nitrosamines (J. Asensio, PhD thesis 2020, Thermal and catalytic pyrolysis of nicotine and NNK and NNN, two tobacco-specific nitrosamines).

The effect produced by inserting a hole into a vapor stream has long been known. The use of this in systems for condensing tar from tobacco smoke has also been known for some time, and numerous patents have been filed on the subject, ranging from the initial ones from the 1960s (Tamag Basel AG, Patent Specification 996,891 Date of Application and Filing Complete Specification April 12, 1962 No. 14139/62 Application made in Austria (No. 2969) April 14, 1961 Filter Suitable for Cigarettes, Cigars, or Filter Cartridges), which involved inserting a perforated membrane into the smoke stream and positioning it between the conventional filter and the tobacco column, to more or less sophisticated systems that include special mouthpiece designs to be placed after the conventional cigarette filter. These systems respond to later patents, although they use the same principle as the first patent, that is, passing the smoke stream through a hole. While these systems, based on the same physical principle as the initial patent, have been commercialized and a series of very similar products exist on the market, based on the same concepts and including slight variations, all of them protected by their corresponding patent, no product is known that uses exactly what is reflected in the aforementioned application.

Filters, both their design and the materials they are made of, have been intensively studied. Cellulose acetate is the most widely used and most established material. Various configurations have been described that modify the smoke path through the filter, employing active ingredients and adsorbents capable of reducing tar inhalation. For example, WO2008142420 and WO2008018617, where the active elements are mounted on granular material supports.

Numerous special designs have been described, such as those involving concentric cylinders of adsorbent material inside the cellulose acetate filter; ventilated structures with various membranes (DE19924205658); or helix-shaped slots with adsorbents (EA200401360). The hydrodynamics of the filtration process and the various mechanisms involved have also been thoroughly studied, leading to the development of highly effective systems such as the well-known "tar gard" system, protected by a large number of patents (e.g., US3434480).

They all have a common characteristic: high cost, as they are plastic pieces with a more or less complex design that includes more than one component. However, there is no record of any commercial system of the type described in the 1961 patent. This system could be much cheaper than those marketed later. The reason for this lack of market presence may be due to several causes. The main one could be the lack of a machine capable of manufacturing these filters incorporating these membranes, which, combined with the increased resistance to smoking that this obstacle represents in the mainstream smoke, has prevented this product from reaching the market.

The fundamental factor that could explain the absence of a product with these characteristics on the market may be the difficulty of adapting conventional filter-making machines to incorporate them, as they are not designed to incorporate this type of membrane in conventional filters or cigarettes. This difficulty could be overcome by RYO or MYO tobacco users, who could incorporate them manually when making their cigarettes, but this clearly represents a serious handicap to their commercialization.

Numerous patents have subsequently appeared claiming to maintain smoking resistance with increasing puff count (e.g., EP 0364256 A1 of 19899 by Liew, Tow Pin of Rothmans International Tobacco (UK) Limited, Cigarette filter rod elements and cigarettes incorporating such filter rod elements). However, none of these have been translated into a commercial product, and their costs are high.

An interesting study, "The intractable cigarette ‘filter problem” (by B Harris, Tobacco Control, 2011 20 suppl 1, i10-i16) analyses the history and problems of filters and highlights the existence of a conflict of interest. In addition to the technical difficulties in their design, the strategies of the different actors, tobacco companies, authorities, etc., are addressed, as well as the cost problem in many of the more sophisticated designs. All the solutions adopted present potential advantages and disadvantages and the conclusion is drawn regarding the effectiveness of cellulose acetate filters, which have been commercially established, as well as the efficiency of ventilation in them. However, this article highlights that the problem is still unsolved, so it is necessary to develop new solutions.

DESCRIPTION OF THE INVENTION

The present invention describes a machine for the manufacture of filters of the type that incorporate a primary membrane that is impermeable or semi-impermeable and comprises at least one hole, where said membrane is inseparably sealed to a fibrous membrane that may be, for example, cellulose acetate.

In a preferred embodiment, the machine comprises a carousel configured to rotate on itself, equipped with a plurality of cavities that allow the fibrous membranes to be housed (typically conventional cellulose acetate filters).

The machine may have a plate for perforating the membranes. This perforating plate may be movable and is arranged along a circumferential portion parallel to the carousel housings.

For example, said perforating plate may be provided with a plurality of pins that are coaxial to at least a plurality of the carousel housings.

These perforations can be made mechanically, by laser radiation, or by any other method, such as the use of cores or inserts. However, these perforations cannot be of any diameter or length, since increasing either of these dimensions decreases their effectiveness. Consequently, the perforation plate, instead of pins, can use other mechanical means, such as those described above.

More specifically, the piercing elements are sized to pierce between 0.2% and 30% of the total cross-section of a watertight membrane adhered to the fibrous membranes in the mold.

The perforation can be circular in section, and have a diameter (or equivalent) between 0.5 and 2 mm, preferably between 0.8 and 1.2 mm.

The cut length can be the thickness of the watertight membrane and can penetrate up to an additional 5 mm into the fibrous membrane.

Preferably, the perforation plate is arranged along a circumferential portion parallel to the carousel housings.

In the embodiment with piercing pins, the pins are coaxial to at least a plurality of the carousel housings within the circumferential section covering the piercing plate.

Furthermore, the machine may be provided with sealing elements arranged along a second circumferential portion parallel to the housing, where said second circumferential portion is different from the first circumferential portion, and the sealing elements inseparably seal the watertight membrane with the fibrous membrane.

There are multiple alternatives to solve the problem described above, namely, to inseparably join the main membrane with the fibrous membrane.

In a first example, the sealing elements may be movable heating elements configured to come into intimate contact with the sealing membrane, where said heating elements are heated to temperatures between 180 and 300°C. The sealing membrane (unperforated membrane) is then placed in the mold adjacent to the fibrous membrane, and the sealing is subsequently performed.

In a variant of this first embodiment, alternatively, said heating element is placed in intimate contact with the fibrous membrane to melt and seal one end thereof, which would also be inseparably joined to the membrane, where said heating element is heated to temperatures between 180 and 350°C. Note that, in this variant, the sealed membrane is formed by casting and, consequently, the need to place a sealed membrane in the mold is omitted.

In a second embodiment, the sealing elements comprise a dispenser comprising a roller that impregnates a film of an impermeable sealant at one end of the fibrous membrane arranged in the mold, such that said film forms the sealed membrane. The sealant film has adhesive and impermeable properties and has a viscosity of between 5000 cp and 25000 cp,

In a third example, the sealing elements are materialized by a movable actuator comprising a plurality of projections whose ends are adhered to a sealed membrane provided with two adhesive faces, and where the actuator moves so that the end exerts pressure on the fibrous membrane, thus joining the sealed membrane to the fibrous membrane.

As for the admission and reception of the fibrous membranes until they are housed in the carousel, the present invention contemplates a plurality of options.

In a preferred embodiment, the machine further comprises an intake disk provided with a plurality of intake housings of semi-cylindrical configuration, where said intake housings comprise internal molds that receive the fibrous membranes.

Depending on the type of sealing element, the mold can also accommodate the watertight membrane arranged adjacent to and in close contact with the fibrous membranes.

Preferably, the machine comprises a hopper with an inverted pyramidal configuration, provided with a lower opening, where said hopper receives the fibrous membranes and dispenses them into the intake housings through the lower opening.

The carousel rotates around itself, preferably by means of a motor, and the intake chambers are filled with fibrous membranes. When sealing is achieved by adhering watertight membranes, these watertight membranes may already be positioned in the mold, and the fibrous membranes fall adjacent to them.

Preferably, an actuator pushes the assembled mold, including the sealing membrane and the fibrous membrane, into the carousel housings for subsequent sealing. Alternatively, the actuator pushes the mold, which comprises only the fibrous membrane.

The machine may be provided with a rear alignment disc comprising a plurality of holes coaxial to the intake housings and the housings, such that the actuator moves coaxially to said holes to push the mold.

Likewise, the machine may be provided with extraction elements arranged along a third circumferential portion parallel to the housing, said third circumferential portion being different from the first and second circumferential portion, where the extraction elements extract the filters from the housing.

Thus, the inlet disc can rotate until it is filled, the actuator pushes the molds onto the carousel, and the carousel executes a sealing step, a piercing step, and an extraction step. By partially rotating the carousel, a plurality of sealed membranes and/or fibrous membranes can execute one step or another and move from one stage to another, significantly increasing the production capacity of the filters.

Preferably, a motor rotates the carousel and control elements regulate the rotation of said motor, executing rotation angles that are defined for the first circumferential portion (piercing stage) and the second circumferential portion (sealing stage).

Note that a plurality of membranes may be sealed, then punctured, and finally removed. While that plurality of membranes is being punctured, another plurality of membranes in another circumferential portion may be sealed, and another plurality comprising the finished filters may be removed.

The machine may have cutting elements, for example in the form of coils, which cut the fibrous membrane at its distal or rear portion once the primary membrane (with a hole) has been sealed to it.

In an embodiment outside the scope of the claims, a manufacturing process for the filter that reduces tar and toxic compounds from tobacco smoke described above is described.

More specifically, the procedure comprises the steps of:

a. ) provide at least one mold,

b. ) place at least one fibrous membrane in the mold,

c. ) inseparably sealing the fibrous membrane with a watertight membrane at at least one end thereof, wherein the sealing is performed by a step selected from a group consisting of:

- impregnating a film with a sealant with adhesive and waterproof properties and having a viscosity of between 5000 cp and 25000 cp, thus forming the watertight membrane directly on the fibrous membrane, - bringing a heating element into intimate contact with the watertight membrane until said watertight membrane is inseparably sealed with the fibrous membrane; or alternatively, bringing said heating element into intimate contact with the fibrous membrane to melt and seal that end, thus forming the watertight membrane which would also be inseparably joined to the membrane, where said heating element is heated to temperatures between 180 and 350 ° C,

- actuating at least one rod having an end that is adhered to the sealed membrane, which in turn comprises a face with an adhesive that is press-fitted to one end of the fibrous membrane by means of an axial force of the rod on it,

d) drill at least one hole in the watertight membrane, said hole having a section of between 0.2% and 30% of the total section of the watertight membrane.

In an exemplary embodiment outside the scope of the claims, the method comprises sealing a watertight membrane at both ends of the fibrous membrane and cutting said fibrous membrane in half, thus generating two filters in each step.

In another embodiment outside the scope of the claims, the fibrous membrane that is placed in the mold is elongated with longitudinal dimensions suitable for manufacturing a plurality of filters from it, and the method further comprises:

- cutting a portion of the fibrous membrane (M3) once the watertight membrane (M4) has been sealed to it and has been pierced to form the hole (2),

- extracting a first filter (1) with the primary membrane (M1) sealed to the fibrous membrane (M3),

- repeat steps b.) to d.),

- cut a second portion of the fibrous membrane (M3),

- extract a second filter (1) with the primary membrane (M1) sealed to the fibrous membrane (M3),

- repeat until the fibrous membrane is exhausted (M3).

The procedure described above would be the one that must be executed to seal each of the filters formed in each housing of the machine's carousel. Consequently, implementing the machine described above to execute this procedure significantly increases filter manufacturing capacity. Furthermore, the steps can be performed simultaneously on the machine for different membranes.

Preferably, the sealant film comprises at least one material selected from a list consisting of:

- cellulose acetate dissolved in acetone,

- polyhydroxybutyrate,

- polylactic acid,

- guar gum,

- starch,

- paintings.

In another embodiment outside the scope of the claims, a filter is described that can be manufactured with the machine or method described above, which comprises a primary membrane intended to be in intimate contact with a distal end of a tobacco column, and which comprises a disc of impermeable or semipermeable material, cylindrical in shape, which is perforated by at least one hole that passes through it in a direction perpendicular to the cross section of the primary membrane, such that the perforated surface has a free passage section of between 0.2% and 30% of the total section of the primary membrane, where the primary membrane is inseparably sealed with a distal end of a fibrous membrane.

In a preferred embodiment outside the scope of the claims, the primary membrane comprises a waterproof paint.

Alternatively, the primary membrane comprises cellulose acetate, formed by the evaporation of a solvent from a concentrated solution thereof.

According to the filter embodiments where the main membrane is formed through a film of a sealant, the resulting thickness is between 200 to 500 microns, preferably between 50 and 200 microns.

In other embodiments, the watertight membrane could have a thickness of up to 5000 microns.

DESCRIPTION OF THE DRAWINGS

To complement the description being made and in order to help better understand the characteristics of the invention, in accordance with a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description, in which the following has been represented for illustrative and non-limiting purposes:

Figure 1a.- Shows a perspective view of a first embodiment of the filter that reduces tar and toxic compounds from tobacco smoke according to a first preferred embodiment of the present invention.

Figure 1b.- Shows a perspective view of a second embodiment of the filter according to a second embodiment of the present invention.

Figure 2.- Shows a front view of a preferred embodiment of the machine for manufacturing the filter of Figure 1, which comprises heating elements for sealing the watertight membrane.

Figure 3.- Shows an exploded perspective view of the preferred embodiment of Figure 2.

Figure 4.- Shows a perspective view of a preferred embodiment of a machine for manufacturing the filter of Figure 1, which comprises a dispenser of a sealing film for forming the watertight membrane.

Figure 5.- Shows a perspective view of a preferred embodiment of a machine for manufacturing the filter of Figure 1, comprising cutting elements and an elongated fibrous membrane suitable for manufacturing a plurality of filters according to Figure 1.

Figure 6.- Shows a perspective view of a preferred embodiment of a machine for manufacturing the filter of Figure 1, comprising an actuator for pressure sealing the primary membrane with an adhesive surface.

PREFERRED EMBODIMENT OF THE INVENTION

Figure 1a shows a perspective view of the filter (1) for reducing tar and toxic compounds from tobacco smoke, obtained with the machine object of the present invention, which comprises a primary membrane (M1) intended to be in intimate contact with a distal end of a column of tobacco (T), and which comprises a disc of impermeable or semipermeable material, of cylindrical shape, which is perforated by at least one hole (2) that passes through it in a direction perpendicular to the cross section of the primary membrane (M1), such that the perforated surface has a free passage section of between 0.2% and 30% of the total section of the primary membrane (M1), where the primary membrane (M1) is inseparably sealed with a distal end of a fibrous membrane (M3).

Figure 1b comprises a filter obtained with the machine according to the present invention, of the type further comprising a secondary membrane (M2) inseparably attached to the opposite end of the fibrous membrane (M3) which in turn comprises a weakened section for a user to cut through said weakened section.

The filter (1) of figure 1b, can also be an intermediate product of the process that will be described later, which comprises cutting the fibrous membrane (M3) in half, generating two filters (1) of the type represented in figure 1a, said filters (1) ready to be used by the user or smoker, or in conventional cigarette making machines.

Figure 2 shows a preferred embodiment of the machine (3) for manufacturing any of the filters (1) of Figure 1a or 1b.

More particularly, according to the preferred embodiment of Figure 2, the machine (3) for manufacturing a filter (1) comprises a carousel (4) configured to rotate on itself, provided with a plurality of housings (5) that receive or comprise a mold with fibrous membranes (M3),

Likewise, in said preferred embodiment, the machine (3) has a movable perforating plate (8) that is arranged along a first circumferential portion parallel to the housings (5).

The perforation plate (8) may be provided by mechanical means or by laser radiation or any other element capable of perforating the hole (2) with the proportions described above.

In the preferred embodiment illustrated by way of example, the perforating plate (8) comprises a plurality of pins which are coaxial to at least a plurality of the housings (5) of the carousel (4), particularly to the housings (5) of the first circumferential portion covering the perforating plate (8).

The machine (3) also comprises a hopper (6) of inverted pyramidal configuration, provided with a lower opening (7), where said hopper (6) receives the fibrous membranes (M3) and dispenses them into admission housings (16) of an admission disk (15) shown in figure 3.

Figure 2 further shows that the machine comprises movable heating elements (10) arranged along a second circumferential portion different from the first circumferential portion where the perforating plate (8) is arranged, and said heating elements (10) are configured to come into intimate contact with a plurality of sealed membranes (M4) arranged in the housings (5) adjacent to the fibrous membranes (M3), where said heating elements (10) are heated to temperatures between 180 and 300°C.

Figure 3 shows a perspective view of the preferred embodiment described. More particularly, it illustrates that the intake disk (15) is provided with a plurality of intake housings (16) of semi-cylindrical configuration, where said intake housings (16) comprise internal molds that receive the fibrous membranes (M3), and the machine (3) also comprises an actuator (not shown) that pushes the mold with the fibrous membrane (M3) and the sealed membrane (M4) to the housings (5) of the carousel (4) for subsequent sealing.

Preferably, as shown in Figure 3, the machine (3) comprises a rear alignment disc (17) comprising a plurality of holes (18) coaxial to the intake housings (16) and the housings (5), such that the actuator moves coaxially to said housings (5) to push the mold.

According to the present invention, the sealed membrane (M4) is the primary membrane (M1) before drilling the hole (2).

As illustrated in Figure 3, in the preferred embodiment described, the machine (3) also comprises extraction elements (9) arranged along a third circumferential portion parallel to the housing (5), said third circumferential portion being different from the first and second circumferential portion, where the extraction elements are configured to extract the filters (1) from the housings (5).

In the preferred embodiment, the extraction elements (9) comprise suction cups (9') or a negative pressure element, which allows the filters (1) already formed to be extracted through the third circumferential portion.

Alternatively, the actuators that introduce the molds into the housings (5) can selectively eject the already formed filters (1) from the housings (5) arranged in the third circumferential portion.

Figure 4 shows an alternative embodiment of the machine (3), particularly as regards the sealing elements for inseparably sealing the fibrous membrane (M3) with the watertight membrane (M4).

In the embodiment of Figure 4, the sealing elements are materialized by a dispenser (11) comprising a roller (11') which in turn comprises a film of an impermeable sealant that is dispensed by the ends of the fibrous membrane (M3) in the mold, such that said sealing film forms the watertight membrane (M4).

In said preferred embodiment, the machine (3) may be provided with drying elements (12), which may be by a blast of hot air, or in the form of heating elements, any of them configured to facilitate the drying of the sealant film.

Figure 5 shows another embodiment where the fibrous membrane (M3) is of the elongated type suitable for forming a plurality of filters (1), and the machine (3) comprises a cutting element (13) for cutting the filter (1) once the watertight membranes (M4) have been perforated and sealed to the fibrous membrane (M3).

In this way, the machine performs an iterative process of sealing, perforating, cutting, and extracting, without the need to constantly feed in new fibrous membranes (M3). It is fed through the hopper only when the elongated column of fibrous material is exhausted.

Figure 6 shows another embodiment that differs only in the elements used for sealing. More particularly, in this embodiment, the sealing elements comprise a movable actuator (14) comprising a plurality of projections (19) whose ends are adhered to a sealed membrane (M4) provided with two adhesive faces, and where the actuator (14) moves and exerts pressure on the fibrous membrane (M3) thus joining the sealed membrane (M4) to the fibrous membrane (M3).

Next, and outside the scope of the claims, a process is described for manufacturing the filter (1), executable by the machine (3) in any of its embodiments described above, where said procedure comprises the steps of:

a. ) provide at least one mold,

b. ) place at least one fibrous membrane (M3) in the mold,

c. ) inseparably sealing the fibrous membrane (M3) with a watertight membrane (M4) at at least one end thereof, where the sealing is carried out by a step selected from a group consisting of:

- impregnating a film with a sealant with adhesive and waterproof properties and having a viscosity of between 5000cp and 25000cp, thus forming the watertight membrane (M4) directly on the fibrous membrane (M3), - placing a heating element (10) in close contact with the watertight membrane (M4) until said watertight membrane (M4) is inseparably sealed with the fibrous membrane (M3); or alternatively, bringing said heating element into intimate contact with the fibrous membrane (M3) to melt and seal that end thus forming the sealed membrane (M4), which would also be inseparably joined to the membrane (M3), where said heating element (10) is heated to temperatures between 180 and 350°C, - actuating at least one rod having an end that is adhered to the sealed membrane (M4) which in turn comprises a face with an adhesive that is press-fitted to one end of the fibrous membrane (M3) by an axial force exerted by the rod thereon,

d) perforate at least one hole (2) in the watertight membrane (M4), said hole (2) presenting a section of between 0.2% and 30% of the total section of the watertight membrane (M4).

Preferably, the method comprises sealing a watertight membrane (M4) at both ends of the fibrous membrane (M3) and then cutting it substantially in half.

To do this, the thickness of the carousel (4) could be that required for two filters (1), and could comprise the sealing elements and the perforation plate (8) on each side. Finally, the fibrous membrane is cut in half, thus generating two final filters (1) for each housing.

In another embodiment of the method, outside the scope of the claims, it comprises:

- providing an elongated fibrous membrane (M3) with longitudinal dimensions suitable for manufacturing a plurality of filters (1) from it,

- cutting a portion of the fibrous membrane (M3) once the watertight membrane (M4) has been sealed to it and has been pierced to form the hole (2),

- extracting a first filter (1) with the primary membrane (M1) sealed to the fibrous membrane (M3),

- repeat steps b.) to d.),

- cut a second portion of the fibrous membrane (M3),

- extract a second filter (1) with the primary membrane (M1) sealed to the fibrous membrane (M3),

- repeat until the fibrous membrane is exhausted (M3).

EXAMPLES

To illustrate the effect of these membranes, as well as the possible manufacturing and use methods, various smoking experiments were conducted with 3R4F tobacco from the University of Kentucky. The conditioning and smoking conditions described in ISO 3308 were used for both the reference cigarettes and those using the different membranes in the examples. To prepare the cigarettes, the tobacco was emptied from the 3R4F cigarettes. The same 3R4F tubes were always used, incorporating the filters described above: either the filters themselves (removed and replaced) or the filters including the corresponding membrane (M1). A smoking machine was used that complied with the specifications of ISO 3308. The gases obtained were analyzed, as well as the composition of the condensed matter in Cambridge filters located downstream of the filters studied, which corresponds to the tars that the smoker would inhale. Various experiments have been carried out with membranes made of paper, cardboard, and 2 mm thick EVA foam sheets, all obtained by die-cutting and positioned appropriately in 3R4F cigarette tubes. These membranes were also obtained by surface fusion of the end of the filter in contact with the tobacco and subsequent perforation, by depositing a film of cellulose acetate solution on the same end of the filter and subsequent perforation, by painting with acrylic paint and subsequent perforation, and other implementations. All of these membranes yielded the same results depending on the diameter of the holes; therefore, only some of them are presented.

In all cases, 15 cigarettes were smoked, following the specifications of ISO 3308 (2-s puffs, 35 mL inhaled volume, 60-s puff frequency, and a pressure drop during the puff of less than 300 Pa, with smoking up to 4 mm from the filter). All samples generated pressure drops lower than those specified.

Cigarettes are conditioned at room temperature and 60% relative humidity, keeping them in a desiccator provided with a saturated solution of sodium nitrite, for at least 48 hours before being smoked.

The condensable products retained in the post-filter trap are extracted with 2-propanol, ensuring that all compounds retained in the trap are recovered. The extract is then dried with sodium sulfate and set aside for subsequent GC analysis.

The determination of CO and CO2 content in the non-condensable fraction was carried out by GC, using a thermal conductivity detector (GC-TCD) and a CTRI concentric column, on a SHIMADZU GC-14A instrument, calibrated with external standards. Quantification was performed by calculating the response factor.

The compounds present in the condensed fraction are analyzed by GC with mass spectrometry detector (GC-MS), using an HP-5MS column.

Compounds were identified using the Wiley MS library.

Below, we will describe some exemplary implementations of the results of using this type of system in smoking experiments.

Realization 1

The first example shows the result of using a membrane consisting of an 8 mm diameter circle of filter paper with a 1 mm diameter perforation. This primary membrane is located between the tobacco column (T) and the 8 mm diameter, 17 mm long cellulose acetate filter used in 3R4F cigarettes.

Significant tar condensation occurs immediately after the hole. The end of the conventional filter in contact with the smoker is considerably less dirty than if the perforated membrane were not used. Table 1 shows the nicotine, tar, and carbon monoxide collected in the gas stream and in the condensate in the Cambridge filter located downstream of the cigarette. It also shows the concentrations of several major compounds in the chromatogram corresponding to the gases and condensate products. The perforated membrane generated a reduction of approximately 57% in nicotine and tar. In the case of CO and other compounds present in the gases, the reduction obtained is smaller.

Table 1. Reductions obtained using the 8 mm diameter perforated cardboard membrane with a 1 mm diameter orifice and conventional filter (MF), compared to using only the conventional filter (F). (Reduction = 100x (mass of product using F - mass of product using MF)/mass of product using F)

Realization 2

Cigarettes have been smoked using filters of the same type as those described in the first embodiment but with holes of different diameters (0.8, 0.9, 1.0 and 1.1 mm). It has been observed that the reductions increase with decreasing hole diameter, but the pressure loss increases considerably, so it would not be viable to use a single perforation of less than 0.9 mm in diameter. It has also been tested by increasing the number of holes of the same diameter, and it has been verified that the reductions decrease with increasing their number.

Table 2. Reductions (%) obtained with filters with 0.8 orifice membranes,

0.9, 1 and 1.1 mm.

Realization 3

Modified filters have been prepared to include the perforated membrane by two methods. The first was carried out on a prototype machine that includes a mold in which the filter is positioned, a temperature-controlled hot plate that allows partial melting of the filter material, and a tool that allows the molten layer to be perforated. Another alternative method consisted of preparing a concentrated solution of cellulose acetate in acetone, impregnating one of the filter's outer surfaces with said concentrated solution, and subsequently evaporating the solvent to generate the impermeable film (membrane). The membrane was subsequently perforated using the tool described above. The results obtained with these filters, which include the membrane with a 1 mm hole, were completely analogous to those described in embodiment 1. This system has the additional advantage that the membrane is inseparable from the filter, which is a very important aspect for the user, allows mass production of these filters, and is the main advance of the present invention.

Claims (13)

1. - Machine for manufacturing a filter (1) to reduce tar and toxic compounds from tobacco smoke, characterized in that it comprises: - a carousel (4) configured to rotate on itself, provided with a plurality of housings (5) that receive or comprise a mold with fibrous membranes (M3), - a movable perforating plate (8) arranged along a circumferential portion parallel to the housings (5), said perforating plate (8) provided with a plurality of spikes that are coaxial to at least a plurality of the housings (5) of the carousel (4), and are sized to perforate between 0.2% and 30% of the total section of a sealed membrane (M4) adjacent to the fibrous membranes (M3) in the mold, - sealing elements arranged along a second circumferential portion parallel to the housing (5), said second circumferential portion distinct from the first circumferential portion, wherein said sealing elements inseparably seal the watertight membrane (M4) with the fibrous membrane (M3). 2. - The machine of claim 1, wherein in each housing (5), the sealed membrane (M4) is placed in the mold adjacent to the fibrous membrane (M3) and the sealing elements comprise movable heating elements (10) configured to come into intimate contact with the sealed membrane (M4), where said heating elements (10) are heated to temperatures between 180 to 300°C, 3. - The machine of claim 1, wherein the sealing elements comprise movable heating elements (10) configured to come into intimate contact with the fibrous membrane (M3) to melt and seal that end, thus forming the sealed membrane (M4), which would be inseparably attached to the fibrous membrane (M3), 4. - The machine of claim 1, wherein the sealing elements comprise a dispenser (11) comprising a roller (11') which in turn comprises a film of an impermeable sealant that is dispensed at one end of the fibrous membrane (M3) that is arranged in the mold, where said film forms the sealed membrane (M4). 5. - The machine of claim 4, wherein it is provided with drying elements (12) configured to facilitate drying of the sealant film. 6. - The machine of claim 1, wherein the sealing elements comprise a movable actuator (14) comprising a plurality of projections (19) whose ends are adhered to a sealed membrane (M4) provided with two adhesive faces, and where the actuator (14) moves and exerts pressure on the fibrous membrane (M3) thus joining the sealed membrane (M4) to the fibrous membrane (M3). 7. - The machine of any one of claims 3 to 6, comprising an intake disk (15) provided with a plurality of intake housings (16) of semi-cylindrical configuration, where said intake housings (16) comprise internal molds that receive the fibrous membranes (M3), and an actuator that pushes the mold with the fibrous membrane (M3) to the housings (5) of the carousel (4) for subsequent sealing. 8. - The machine of claim 2, comprising an intake disk (15) provided with a plurality of intake housings (16) of semi-cylindrical configuration, where said intake housings (16) comprise internal molds that receive the fibrous membranes (M3) contiguous to the sealed membranes (M4) that are arranged in said mold, and the machine (3) further comprises an actuator that pushes the assembled mold with the sealed membrane (M4) and the fibrous membrane (M3) to the housings (5) of the carousel (4) for subsequent sealing. 9. - The machine of any one of claims 7 or 8, comprising a rear alignment disc (17) which in turn comprises a plurality of holes (18) coaxial to the intake housings (16) and the housings (5), such that the actuator is coaxially movable to said housings (5) to push the mold. 10. - The machine of any one of claims 7 to 9, comprising a hopper (6) of inverted pyramidal configuration, provided with a lower opening (7), where said hopper (6) receives the fibrous membranes (M3) and dispenses them into the intake housings (16) through the lower opening (7). 11. - The machine of any one of the preceding claims, comprising extraction elements (9) arranged along a third circumferential portion parallel to the housing (5), said third circumferential portion being different from the first and second circumferential portion, where the extraction elements are configured to extract the filters (1) from the housings (5). 12.- The machine of any one of the preceding claims, comprising one or more cutting elements (13) arranged in a fourth circumferential portion different from the first and second circumferential portion, where said cutting elements (13) are configured to cut the filter (1) once the sealed membranes (M4) have been sealed to the fibrous membrane (M3). 13.- The machine of any one of the preceding claims, comprising a motor that rotates the carousel (4) and control elements configured to control the motor and rotate the carousel through rotation angles that are defined by at least the first circumferential portion and the second circumferential portion.