Aerosol generating articles

Abstract

A filter part (1, 1′) for use in an aerosol generating article and a method of manufacturing the filter part (1, 1′). The filter part (1, 1′) includes an aerosol permeable core (2) within a sleeve (3) formed integrally therearound. The core (2) is shorter than the integrally formed sleeve (3). The method includes conveying a plurality of aerosol permeable cores (2) along a conveying path at a first speed (S1) and forming a sleeve (3) around each core (2) at a second speed (S2). The second speed (S2) is greater than the first speed (S1) to generate a space between consecutive cores (2) within the sleeve (3).

Claims

1. An aerosol generating article comprising: an aerosol permeation element comprising an aerosol permeable core within an extruded sleeve formed integrally therearound, wherein the aerosol permeable core is shorter than the extruded sleeve; the aerosol permeation element comprises one end that is hollow and the other end of the aerosol permeation element comprises the aerosol permeable core; and, a rod of aerosol generating material, wherein a portion thereof is received within the hollow end of the aerosol permeation element; wherein the aerosol permeation element is a filter, a spacer or a cooling element.

2. The aerosol generating article according to claim 1, wherein the aerosol permeable core, is no more than half of the length of the sleeve.

3. The aerosol generating article according to claim 1, wherein the sleeve comprises a polymeric extrusion.

4. The aerosol generating article according to claim 1, wherein the aerosol permeable core comprises a foamed polymeric extrusion with one or more pathways described therealong.

5. The aerosol generating article according to claim 1, wherein the sleeve comprises a poly lactic acid material.

6. The aerosol generating article according to claim 1, wherein the aerosol permeable core comprises a poly lactic acid, acetate or cellulose material.

7. The aerosol generating article according to claim 1, wherein the sleeve comprises a wall thickness of between 0.3 millimetres and 3 millimetres.

8. The aerosol generating article according to claim 1, wherein the aerosol permeable core comprises a diameter of between 4 millimetres and 7.5 millimetres.

Description

(1) Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

(2) FIG. 1 is a perspective view of an aerosol permeation element according to an embodiment of the invention;

(3) FIG. 2 is cross-sectional view of an aerosol permeation element according to another embodiment of the invention;

(4) FIG. 3 is a schematic of a filter manufacturing apparatus according to an embodiment of the invention;

(5) FIG. 4 is a schematic of part of the filter manufacturing apparatus of FIG. 3;

(6) FIG. 5 illustrates the positions at which the filter rod may be severed by the apparatus of FIG. 3;

(7) FIG. 6 is a schematic of a core former according to an embodiment of the invention; and

(8) FIG. 7 is a cross-sectional view through the core die of the core former of FIG. 6.

(9) Referring now to FIGS. 1 and 2, there is shown two variations of an aerosol permeation element or filter part 1, 1′ according to embodiments of the invention for use in an aerosol generating article (shown in outline). The filter part 1, 1′ includes an aerosol permeable core 2 of extruded polymeric filter material within an extruded polymeric sleeve 3 surrounding it.

(10) The core 2 has a plurality of pathways 21 described within it and the configuration shown in FIG. 2 also includes a plurality of channels 22 described in an outer surface thereof. The pathways 21 and channels 22 extend along the axial length L1 of the core 2. The core 2 has first end surface 23 and second end surface 24, spaced from one another by the distance L1. The core 2 is formed from a poly lactic acid (PLA) material in this embodiment and has a diameter D of 5 millimetres.

(11) The sleeve 3 surrounds and is formed integrally with the core 2 and is also formed from poly lactic acid (PLA) in this embodiment. The sleeve 3 has a wall thickness W of 1 millimetre and an axial length L2. The length L2 of the sleeve 3 is greater than the length L1 of the core 2, such that the filter part 1, 1′ has a hollow end 4 beyond the first end surface 23 of the core 2. The second end 24 of the core 2 is aligned with an end surface of the sleeve 3. The channels 22 in the outer surface of the core 2 define, together with the internal surface of the sleeve 3, pathways 25.

(12) In use, the hollow end 4 of the filter part 1, 1′ allows part of the aerosol generating article to be mounted therein to provide a degree of overlapping interface between the aerosol generating article and the filter part 1, 1′. The inner surface of the sleeve 3 may provide a friction fit with another part of the aerosol generating article. In some embodiments, the sleeve 3 extends the entire length of the aerosol generating article, such that the aerosol generating substance is contained within the hollow end 4.

(13) Referring now to FIGS. 3 and 4, there is shown an apparatus 100 for manufacturing a filter part 1, 1′ as described above. The apparatus 100 includes a core feed 110, which feeds cores 2 through an extrusion die 120 at a predetermined speed S1. Extruded sleeve material is fed continuously from a screw extruder 125 through the die 120 and is deposited on the cores 2 to form a continuous length of filter rod 5. The filter rod 5 is drawn from the die 120 at speed S2, which is greater than core feed speed S1. This difference in speed (S2-S1) creates a space between consecutive cores 2 within the extruded sleeve material. The so-formed filter rod 5 is drawn through a cooling unit 130 downstream of the die 120 using a drawing mechanism 140 and on to a cutting station 150 for severing the continuous length of filter rod 5 to produce a plurality of filter parts 1, 1′.

(14) The filter feed 110 has a pair of opposed, counter-rotating feed rollers 111, 112 configured to rotate at speed R1 to provide the core feed speed S1. As illustrated more clearly in FIG. 4, a feed tube 113 is provided downstream of the feed rollers 111, 112. The feed tube 113 has an inner diameter slightly greater than the diameter D of the cores 2. The feed tube 113 is configured to correctly position each respective core 2 as it is fed into the die 120 and protrudes from both the upstream and downstream sides of the die 120. The die 120 has a central aperture 121 through which the feed tube 113. The die 120 also has a feed channel 122, which feeds into an annular chamber 123 and out through an annular passage 124. The annular chamber 123 and annular passage 124 both surround the central aperture 121. The extruder 125 has a hopper 126 for feeding raw material thereto, which is melted and fed into the annular chamber 123. The raw material is in the form of poly lactic acid (PLA) resin in this embodiment.

(15) Downstream of the die 120 is the cooling unit 130, which includes a tank 131 containing a cooling medium, which is water 132 in this embodiment. Extruded material is drawn from the annular passage 124 of the die 120, into a cooling inlet 133 in a wall of the tank 131 and through a diameter verification device 134, which is below the surface of the water 132. The diameter verification device 134 is tubular with an internal diameter which is substantially the same as the diameter of the filter rod 5 and substantially smaller than the annular passage 124. As such, the extruded material forms a conical tube as it passes from the annular passage 124 of the die to the cooling inlet 133 of the tank 131.

(16) The drawing mechanism 140 is downstream of the cooling unit 130 and includes a pair of opposed, counter-rotating pulling rollers 141, 142 arranged to receive the filter rod 5 after it has passed through the cooling unit 130. The pulling rollers 141, 142 receive the filter rod 5 therebetween, draw it through the cooling unit 130 and covey it towards the cutting station 150 at speed S2. The cutting station 150 has an inlet 151, a cutter (not shown) for cutting the filter rod 5 into filter parts 1, 1′ and an outlet 152 through which the filter parts 1, 1′ are expelled.

(17) In use, cores 2 are fed into the feed tube 113 by the feed rollers 111, 112. Each successive core 2 fed into the feed tube 113 pushes the others along the conveying direction of the apparatus 100 and into the die 120. As the cores 2 are conveyed, they pass through the die 120 and exit the feed tube 113 into the conical tubular extrusion of material as it enters the cooling inlet 133 of the tank 131. The sleeve material from the annular passage 124 of the die 120 is drawn at speed S2 as it contacts each core 2 and enters the cooling inlet 133 of tank 131. As such, the cores 2 are drawn into the cooling inlet 133 of the tank 131 at speed S2 as they come into contact with extruded sleeve material from the die 120, which creates a space between consecutive cores 2 in the filter rod 5.

(18) As the filter rod 5 is drawn through the cooling unit 130 by the drawing mechanism 140, it cools and solidifies the extruded sleeve 3. The filter rod 5 is also drawn through the diameter verification device 134 which ensures the diameter of the filter rod 5 is correct. The filter rod 5 is then fed into the cutting station 150 through the inlet 151 and is cut to form the filter parts 1, 1′, which then exit the cutting station 150 through the outlet 152.

(19) Turning now to FIG. 5, the filter rod 5 may be cut into regular segments by providing a first cut through the core 2 and sleeve 3 at the midpoint of the core 2 and a second cut through the sleeve 3 at the midpoint of the space between adjacent cores 2. This cutting arrangement produces filter parts 1, 1′ with a core 2 having length L1 which is half of the length of the core 2 supplied to the apparatus 100 at the core feed 110. This cutting arrangement also produces a sleeve 3 with a length L2, which greater than L1. As such, the filter part 1, 1′ has the hollow end 4 adjacent the first end 23 of the core 2 and the second end 24 of the core 2 aligned with an end surface of the sleeve 3. Alternatively, the cores 2 supplied to the apparatus 100 may have a length equal to L1, wherein the sleeve 3 of the filter rod 5 is simply cut adjacent the second end 24 of each consecutive core 2.

(20) FIGS. 6 and 7 show an optional core former 200 for use with the apparatus 100. The core former 200 includes an extruder 210, which forms a continuous extruded core 6 through a core die 220. The extruded core 6 is drawn from the core die 220 through a cooling unit 230 using a core drawing mechanism 240. Downstream of the core drawing mechanism 240, the extruded core 6 is fed into a core cutting station 250, which severs the extruded core 6 to produce a plurality of cores 2 for supply to the apparatus 100.

(21) The core extruder 210 has a hopper 211 for feeding raw material, a poly lactic acid (PLA) resin in this embodiment, to the core extruder 210. At the downstream end of the core extruder 210 is a flow channel 212 leading to the core die 220. The core die 220 has a male part 221 and a female part 222 described by an outer wall 223 that defines the outer surface of the extrusion. The male part 221 is supported within the female part 222 by support elements (not shown) and has a plurality of core members 224 each having a circular cross-section for creating the pathways 21 within the extrusion. The circular core members 224 together define a star pattern so as to form the pathways 21 along the extrusion 6. The core die 220 is attached to the outlet of the core extruder 210 for receiving molten material therefrom. Optionally, the male part 221 may rotate within the female part 222 such that the core members 224 create helical or helicoidal pathways 21 within the extrusion. The helical angle of the pathways 21 may be controlled by the speed of rotation of the male part 221 relative to the drawing speed of the extrusion.

(22) Downstream of the core die 220 is the cooling unit 230 which, similar to the cooling unit 130 of apparatus 100, includes a tank 231 having a cooling medium therein. Extruded material 60 is drawn by the drawing mechanism 240 from the extruder 210 into a cooling inlet 232 in a wall of the tank 231, which causes it to form a conical extrusion 60 in a similar manner to the sleeve extrusion process described above. The drawing mechanism 240 includes a pair of opposed, counter-rotating pulling rollers 241, 242 arranged to draw the extruded core 6 from the cooling unit 230. The pulling rollers 241, 242 convey the extruded core 6 into the core cutting station 250, which cuts the core extrusion 6 into individual cores 2.

(23) In use, raw material for forming the cores 2 is fed from the hopper 211 through the extruder 210. Extruded core material 60 is drawn through the cooling unit 230 by the drawing mechanism 240, which cools and solidifies it into the core extrusion 6 ready for further processing. The core extrusion 6 is drawn by the pulling rollers 241, 242 of the drawing mechanism 240 and fed to the cutting station 250.

(24) The core former 200 may be located upstream of the core feed 110 shown in FIGS. 3 and 4. The cores 2 produced at the outlet 252 of the core cutting station 250 may be fed to the inlet of the core feed 110. In other embodiments, the core former 200 is completely separate from the apparatus 100.

(25) In some embodiments, the core former 200 may not have a core cutting station 250 and instead the extruded core may be stored on a roll. In such a case, the apparatus 100 may have a core cutter upstream of the core feed 110 so as to form cores 2 prior to feeding. Other arrangements are also envisaged.

(26) It will be appreciated by those skilled in the art that the parameters of the filter part 1, 1′ may be altered by changing one or more processing parameters. For example, the thickness of the sleeve 3 may be increased or decreased by modifying the relationship between the drawing speed S2 and the rate at which extruded material is supplied by the extruder 125.

(27) As such, the invention provides a versatile means of producing aerosol permeation elements 1 whose characteristics can be varied across a wide range.

(28) It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. For example, the cooling medium in the cooling units 130, 230 is described as being water. This need not be the case and instead, any suitable cooling medium may be used. The extruded sleeve 3 and core 2 may be formed of different materials to those described above. Additionally or alternatively, the core 2 may, but need not, be formed of a foamed material. It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.

EXAMPLES

(29) 1. An aerosol permeation element for use in an aerosol generating article, the aerosol permeation element comprising an aerosol permeable core within a sleeve formed integrally therearound, wherein the core is shorter than the integrally formed sleeve. 2. Aerosol permeation element according to example 1, wherein the core is no more than half of the length of the sleeve. 3. Aerosol permeation element according to example 1 or example 2, wherein the sleeve comprises a polymeric extrusion. 4. Aerosol permeation element according to any preceding example, wherein the core comprises a foamed polymeric extrusion with one or more pathways described therealong. 5. Aerosol permeation element according to any preceding example, wherein the sleeve comprises a poly lactic acid material. 6. Aerosol permeation element according to any preceding example, wherein the core comprises a poly lactic acid, acetate or cellulose material. 7. Aerosol permeation element according to any preceding example, wherein the sleeve comprises a wall thickness of between 0.3 millimetres and 3 millimetres. 8. Aerosol permeation element according to any preceding example, wherein the core comprises a diameter of between 4 millimetres and 7.5 millimetres. 9. An aerosol generating article comprising an aerosol permeation element according to any preceding example.