TECHNICAL FIELD

The present invention is directed to an insulation sleeve for an aerosol generation device.

BACKGROUND

An aerosol generation device is now a mainstream alternative product to traditional cigarettes. There are currently mostly two types of aerosol generation devices. The first one, known generically as e-cigarettes, relies on the heating of a liquid substrate (e- liquid) to form an inhalable aerosol (also called vapour). The second one, known generically as Heat-not-Burn (HNB), relies on the heating of a solid or semi-solid tobacco based material admixed with an aerosol former such as vegetal glycerin or propylene glycol to a temperature below the combustion temperature of the solid-or semi-solid substrate but higher than the evaporation temperature of the aerosol former to generate a tobacco flavored inhalable aerosol. The advantage of the HNB -type devices and consumable is that the aerosol generated has a real tobacco flavor but none or less of by-products usually generated through the combustion of traditional cigarettes. The operation method of the aerosol generation device is to contain an aerosol generation substrate inside and to heat it, but not to its burning point.

For HNB aerosol generation devices in particular, to insulate the heat coming from the heater is crucial for both the other components of the device and a user’s safety. Indeed, during operation of the aerosol generation device the heater can easily get overly hot and burn, which may affect the other units in the aerosol generation device due to the continuous high temperature of the heater. Likewise, the heat radiated by the heater may reach the surface of the outer casing of device, where a user holds the device by hand, Excessive surface temperature of more than 40°C can not only be uncomfortable but dangerous for users. Heat insulation happens to be particularly difficult in HNB devices because the room available in the device housing to accommodate high- performance insulators capable of dampening the heat from the heaters, the working temperature of which often reaches up to 350°C to 450°C, is very limited. Excessive heat essentially derives from improper insulation of the heating chambers receiving a heat-not-burn consumable, which may be caused by various factors such as: reduced thickness or improper choice of insulation materials or arrangement, tightness of structural design of the devices leading to heat conduction to the outside of the device housing, etc. There exist satisfactory insulating solutions, but they are costly and sometimes difficult to implement and to manufacture. For example, EP2802226 discloses an insulating material for use in a Heat-Not-Burn (HNB) smoking article, wherein the insulating material comprises a sol-gel or aerogel, and wherein the material comprises a carbon monoxide (CO) catalyst.

WO2013034458 discloses an insulation sleeve for a cylinder heating chamber, wherein the sleeve is formed of a metallic tube having an inner and an outer envelope sealed together to form an inner insulating void under deep vacuum. The inner envelope is coated with an infra-red reflective coating to limit heat radiation towards to outer envelope.

There is thus a need for an alternative and performant insulation solution for aerosol generating devices which are easy and cost-efficient to implement compared to existing solutions.

SUMMARY OF THE INVENTION

The present invention provides a consumable for an aerosol generation device, which solves some of or all the above-mentioned problems. A 1st embodiment of the invention is directed to an aerosol generating device comprising an insulation sleeve for a heating assembly of the aerosol generating device, wherein the insulation sleeve comprises natural organic fibres. The natural material comprised in the insulation sleeve is easily available and eco-friendly; it also increases the sustainability of the component and devices including it. The cost of manufacturing the insulation sleeve with the natural material is very low.

According to a 2nd embodiment, in the 1st embodiment, the aerosol generating device is configured to detachably contain an aerosol generation consumable and to heat it. According to a 3rd embodiment, in any one of the 1st or 2nd embodiments, the insulation sleeve is configured to insulate heat from the heating assembly.

According to a 4th embodiment, in any one of the preceding embodiments, the fibres have a thermal conductivity of at most 0.10 W/m.K, preferably at most 0.05 W/m.K, even more preferably at most 0.035 W/m.K. According to a 5th embodiment, in any one of the preceding embodiments, the natural organic fibres comprises at least one of: hemp fibres, banana fibres, sisal fibres, kenaf fibres, and jute fibres.

According to a 6th embodiment, in any one of the preceding embodiments, the natural organic fibres are banana peel or stalks fibres. Banana peel or stalks fibres have a surprisingly high thermal insulation capacity compared to most other natural materials.

According to a 7th embodiment, in any one of the preceding embodiments, the fibres are microfibres, preferably having an average diameter of at most 1 mm, more preferably at most 0.5 mm, even more preferably at most 0.3 mm, and most preferably at most about 0.1 mm; and of at least 0.01 mm, more preferably at least 0.03 mm, even more preferably at least 0.05 mm, and most preferably at least about 0.1 mm. Microfibres derived from trunks and stalks of banana trees have a surprising capacity of storing a large volume of air microbubbles, to some extent similar to what crimped cellulose acetate fibres achieve in a standard cigarette filter. According to a 8th embodiment, in any one of the preceding embodiments, the natural organic fibres are combined in a woven or non-woven manner. Accordingly, the material of the insulation sleeve can be rigid, semi-rigid or flexible. According to a 9th embodiment, in any one of the preceding embodiments, the natural organic fibres are combined by using a binder. The combined material has stronger rigidity, higher mechanical strength, is easier formable and more convenient use. Further, the material can contain even more air microbubbles, which can improve the thermal insulation performance of the microfibres of the banana peel or stalks.

According to an 10th embodiment, in the preceding embodiment, the binder is a dry fibrous binder, an aqueous organic binder, or an inorganic aqueous binder.

According to an 11th embodiment, in any one of the preceding embodiments, the insulation sleeve comprises at least 60%, preferably at least 70%, more preferably at least 80%, and most preferably at least 90% of the natural organic fibres, by weight. A low percentage of the binder is less toxic, lower cost and eco-friendlier.

According to a 12th embodiment, in any one of the preceding embodiments, the material forming the sleeve has been compressed with a thickness less than 20mm during manufacturing. According to a 13th embodiment, in any one of the preceding embodiments, the material forming the sleeve comprises casing or packaging material, preferably Phenol formaldehyde or Urea-formaldehyde, other than natural organic fibres which is capable of reducing crumbling of the material forming the sleeve. According to a 14th embodiment, in any one of the preceding embodiments, the insulation sleeve comprises a sheet, pad or mat comprising or formed by the natural organic fibres.

According to a 15th embodiment, in the preceding embodiment, the sheet, pad or mat has an average thickness of at least 1 mm, preferably at least 1.5 mm, more preferably at least about 2 mm, and at most 10 mm, preferably at most 7 mm, more preferably at most about to 5 mm.

According to a 16th embodiment, in any one of the preceding embodiments, the insulation sleeve substantially has the shape of a cylinder. According to a 17th embodiment, in any one of the preceding embodiments, the insulation sleeve is arranged between a heating assembly, in particular a heating chamber, and a housing of the aerosol generating device. Preferred embodiments are now described, by way of example only, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1: shows a schematic drawing of an embodiment of an aerosol generation device, and a partially enlarged view of a thermal insulation sleeve according to the invention on a heating chamber;

Figure 2: shows a teardown diagram of the heating chamber and the insulation sleeve of Figure 1. DETAILED DESCRIPTION

Preferred embodiments of the present invention are described hereinafter and in conjunction with the accompanying drawings.

Referring to Figure 1, one embodiment of an aerosol generation device too comprises a body 102 housing various components of the aerosol generation device too. The body 102 can be of any shape so long as it is sized to fit the components described in the aerosol generation device too. The body 102 can be formed of any suitable material, or indeed layers of material.

The end of the aerosol generation device too at which a closure arrangement 106 is located, shown towards the top of Figure 1, is for convenience referred to as the top or upper end of the aerosol generation device too. The end of the aerosol generation device too that is away from the closure arrangement 106, shown towards the bottom of Figure 1, is for convenience referred to as a bottom, base or lower end of the aerosol generation device 100. During use, the user typically orients the aerosol generation device too with the top end in a proximate position with respect to the user’s mouth and the bottom end in a distal position with respect to the user’s mouth.

The aerosol generation device too comprises a heating assembly 108, more specifically a heating chamber, located towards the top end of the aerosol generation device too. At one end of the heating chamber 108, an aperture 104 through the body 102 is provided. The aperture 104 allows access to the heating chamber 108 from outside the body 102, so that an aerosol-generating consumable (not shown), which may be in the form of a stick, comprising an aerosol-generating substrate (not shown) can be placed into the heating chamber 108 via the aperture 104. In other words, an aerosol generation consumable can be inserted into and then detachably contained in the aerosol generation device too, more specifically, the heating chamber 108, so as to be heated by the aerosol generation device too, more specifically, the heating chamber 108, when the user wants to consume the consumable. The heating assembly 108 is powered by and electrically connected with an electric power supply unit, preferably a battery, such as Lithium battery (shown as a block with slashes in the aerosol generation device too in Figure 1), comprised by the aerosol generation device too.

At the aperture 104, where the heating chamber 108 is proximate to the body 102, one or more spacing elements can be provided to hold the heating chamber 108 in position. The spacing elements are arranged and configured to reduce the conduction of heat from the heating chamber 108 to the body. There is typically an air gap otherwise surrounding the heating chamber 108, so that transfer of heat from the heating chamber 108 to the body 102 other than via the spacing elements is reduced. However, the heat insulation made by air may not be sufficient.

In order to increase the thermal isolation, i.e. the thermal insulation performance, of the heating chamber 108, the heating chamber 108 is in addition surrounded by an insulation sleeve 200, shown in the partially enlarged part of Figure 1. Figure 2 shows a teardown diagram of the heating chamber and the insulation sleeve 200 for thermal insulation, which is configured to insulate the heat from the heating assembly. As shown in the figure, the insulation sleeve is substantially of the same shape as the heating chamber 108. It will be appreciated that any shape of the heating chamber 108 may be used. In other embodiments, the insulation sleeve 200 may be used in a different shape from the heating chamber 108 or the aperture. The insulation sleeve 200 may be shaped, along with the other units of the aerosol generation device too, so that there is more space and air between the insulation sleeve 200 and the heating chamber 108, in order to improve the thermal insulation performance. Preferably, as shown in Figure 2, the heating chamber is cylindrical, and the thermal insulation 200 is also cylindrical so that the heat from the heating chamber 108 can be evenly insulated by the insulation sleeve 200 and the cylindrical shape of the insulation sleeve 200 ensures that the insulation sleeve and the heating chamber 108 require minimal space in the aerosol generation device. In this embodiment, as shown in the figure, a flange 1081 can be formed at the end of the of the heating chamber 108 to provide a mounting hold for the chamber in the housing 102. The flange 1081 further serves as a stopper for abutting the insulation sleeve 200 that is fit is over the tube part 1082 of the heating chamber 108. A washer or ring (not shown) may be provided at the opposite end of the tube 108 to maintain the insulation sleeve in place against the tube. A fibrous material is used for insulation sleeve 200; specifically, the insulation sleeve 200 comprises natural organic fibres, more specifically, at least one type of jute fibres, kenaf fibres, hemp fibres, sisal fibres and banana fibres, preferably, banana peel and/or stalks fibres. Other natural organic fibres with high thermal insulation performance are also appreciated to be used. The thermal insulation performance of the natural organic fibres should have a thermal conductivity lower than 0.10 W/ m.K, preferably lower than 0.05 W/m.K, more preferably lower than o.035W/m.K, even more preferably lower than 0.030 W/m.K. In some embodiments, the insulation sleeve comprises a pair of nested tubes or cups enclosing a cavity therebetween. The cavity can be filled with natural organic fibres with high thermally insulating performance, and may also comprise other thermally insulating material, for example, foams, gels or gases (e.g. at low pressure). Alternatively, or in addition, the cavity may comprise a vacuum, which advantageously requires very little thickness to achieve a high thermal insulation. Banana peel or stalks fibres, as well as hemp fibres for example, can be used in the insulation sleeve 200 as raw materials in their natural states.

The natural fibres used may preferably be microfibres from stalks or stems of banana trees. Preferably, the fibres have an average diameter of at most 1 mm, more preferably at most 0.5 mm, even more preferably at most 0.3 mm, and most preferably at most about 0.1 mm; and of at least 0.01 mm, more preferably at least 0.03 mm, even more preferably at least 0.05 mm, and most preferably at least about 0.1 mm. In order to produce the microfibres, the banana peel or stalks are unraveled after being obtained directly from the raw materials so that the fibers are separated into microfibres. In some embodiments, the microfibres need to be further processed, such as by hydraulic pressing, pre-drying, and further unraveling. The process of processing the microfibres can be any well-known microfibres production method.

Microfibres derived from trunks and stalks of banana trees have a surprising capacity of storing a large volume of air microbubbles, to some extent similar to what crimped cellulose acetate fibres achieve in a standard cigarette filter. This is mainly the reason why materials from such microfibres exhibit high thermal insulation compared with other natural fibres.

Preferably, the insulation sleeve comprises a sheet, pad or mat comprising or formed by the natural organic fibres. The natural organic fibre material forming the mat, sheet, or pad may also be combined with other casing or packaging materials, such as Phenol formaldehyde or Urea-formaldehyde, in particular for the safety and integrity upon integration in the device so as to avoid crumbs of fibres.

In some embodiments, the material used in manufacturing the sheet, pad or mat is used in its native state. In other embodiments, the material is compressed and thereby compacted. While natural fibres usually tend to require higher thickness than synthetic insulants, banana peel or stalks fibres like hemp fibres do exhibit their insulation power even in a compressed state; for example, the compressed material can have a thermal conductivity of around 0.05 W/m.K, with a thickness less than 20 mm. In a preferred embodiment, the sheet, pad or mat has an average thickness of at least 1 mm, preferably at least 1.5 mm, more preferably at least about 3 mm, and at most 10 mm, preferably at most 7 mm, more preferably at most about to 5 mm.

The material, in particular the compacted material, may be combined by using a binder. The binder may be a dry fibrous binder, an aqueous organic binder, or an inorganic aqueous binder, etc. With the mixture of the binder, the insulation sleeve can contain even more air microbubbles, which can improve the thermal insulation performance of the microfibres of the banana peel or stalks. In particular, the material like microfibres of banana peel or stalks are combined with a small amount of binder in a liquid state, and hence the insulation sleeve comprises at least 60%, preferably at least 70%, more preferably at least 80%, and most preferably at least 90% of the microfibres of banana peel or stalks, by dry weight. A low percentage of the binder is less toxic, lower cost and eco-friendlier. In another preferred embodiment, the banana peel or stalks fibres are combined in a woven manner, preferably formed by weaving the microfibres. Finally, the sheet, pad or mat can be rolled up into a sleeve shape and arranged about the heating chamber of the aerosol generation device. Generally, the insulation sleeve can be made of various forms of boards or rolls of varying dimensions, thicknesses and density. With the use of microfibres of banana peel or stalks, the material made of the insulation sleeve can be rigid, semi-rigid or flexible.