TW202421015A - Element for an aerosol generating article or smoking article - Google Patents

Abstract

There is disclosed an element 100 for an aerosol generating article or a smoking article comprising a longitudinally extending hollow tube 101; a layer 102 comprising filler material, wherein the layer 102 is engaged around the hollow tube 101; and a wrapper 103 engaged around the layer 102; wherein the hollow tube 101 comprises a helically wound sheet of material and wherein the helically wound sheet of material has partially overlapping helical turns.

Description

Components for aerosol-generating or smoking products

The present invention relates to a device for use in aerosol generating products such as heated tobacco products or in smoking products such as cigarettes.

The use of tubular elements in aerosol generating products and smoking products is well known in the art. Typically, the tubular element comprises a cylindrical core of filter material including a conduit extending longitudinally from one end of the cylindrical core. In such products, the tubular element usually comprises a modified tobacco plug and other elements, such as a coated filter material plug.

The tubular element may be disposed at the mouth end of the aerosol generating product to provide a special final appearance and to concentrate the aerosol into the air stream directed toward the user's tongue. Optionally, the tubular element may be used as a mid-section or at the tobacco end of the aerosol generating product to facilitate the passage of the aerosol from the tobacco section into other elements and/or to cool the aerosol before it reaches the mouthpiece. In a smoking product, the tubular element may be disposed at the mouth end to provide a special final appearance and to reduce contamination of the appearance. Optionally, the tubular element may be used as a mid-section or at the tobacco end of the smoking article where it may facilitate passage of tobacco smoke from the tobacco section into other elements, thereby acting as a reservoir to concentrate the tobacco smoke and enhance nicotine delivery to the user.

In the past, cellulose acetate tow has been used as the filter material for the tubular elements because it can be manufactured into tubes having the desired stiffness, structural integrity, and defined conduits. The manufacture of such tubular elements can be performed in a single continuous process. However, cellulose acetate tow is not readily biodegradable, and as a result, aerosol generating product elements and smoking product elements containing cellulose acetate tow can remain in the environment for many years.

Components for aerosol generating products and smoking products have been made from readily biodegradable materials such as paper. However, it has previously been challenging to make tubular components from paper or other readily biodegradable materials while maintaining the stiffness and structural integrity associated with aerosol generating product components and smoking product components made from cellulose acetate tow.

There is a need for tubular elements for use in aerosol generating articles or smoking articles that have improved biodegradability compared to tubular elements comprising cellulose acetate tow and that have a desired stiffness and structural integrity, e.g., stiffness and structural integrity similar to existing elements for use in aerosol generating articles and smoking articles formed from cellulose acetate tow. There is also a need for methods of making such tubular elements.

In one aspect of the invention, there is provided an element for an aerosol generating product or smoking product comprising a longitudinally extending hollow tube; a layer comprising a filler material, wherein the layer is engaged around the hollow tube; and a covering material engaged around the layer; wherein the hollow tube comprises a helically wound sheet of material and wherein the helically wound sheet of material has partially overlapping helical turns.

The aerosol generating product may be a heated tobacco product, such as a heat-not-burn device, a tobacco heating device or the like; or an electronic cigarette.

The smoking product may be a cigarette, a cigar, a cigarillo, a hand-rolled cigarette or the like.

The element may be a mouthpiece, for example, a mouthpiece for an aerosol generating product or a smoking product.

The element may be a cooling element, for example, an element for an aerosol generating product that provides a cooling effect on an aerosol (eg, vapor) or tobacco smoke.

The element may be a filter element, for example, an element for an aerosol generating product or a smoking product that provides a filtering effect on an aerosol (e.g., vapor) or tobacco smoke. Alternatively, the element may not provide a filtering effect on an aerosol (e.g., vapor) or tobacco smoke, for example, the element may have zero or substantially zero aerosol (e.g., vapor) or tobacco smoke filtering effect.

The element can function as both a cooling element and a filter element for an aerosol generating article.

The element may allow the aerosol or tobacco smoke from the tobacco segment to easily pass into other elements of the aerosol-generating product or smoking product (i.e., the aerosol or tobacco smoke may pass through the conduit of the hollow tube into other elements). It will be appreciated that if the element allows the aerosol or tobacco smoke from the tobacco segment to easily pass into other elements of the aerosol-generating product or smoking product, the conduit of the hollow tube may not include any object that may substantially confine the aerosol or tobacco smoke, for example, confine the aerosol or tobacco smoke. In other words, the conduit of the hollow tube may be empty. Thus, the aerosol or tobacco smoke may be substantially not retained by the element, e.g., the aerosol or tobacco smoke is not retained by the element. It will be further appreciated that, when combined with a further element into a multi-stage product, the element may contribute substantially zero, e.g., zero, to the pressure drop of the multi-stage product due to the lack or minimal retention of aerosol or tobacco smoke by the element.

The element may act as a reservoir where tobacco smoke from the tobacco segment is concentrated, for example, the tobacco smoke is concentrated within the conduit of the hollow tube. The applicant has discovered that by concentrating the tobacco smoke within the element, the user may receive highly concentrated smoke and, in addition, improve nicotine delivery.

The element may be substantially cylindrical, for example, cylindrical.

The cross-section of the element may be substantially annular, for example, ring-shaped.

The hollow tube may be a spiral tube.

The hollow tube comprises an outer surface and an inner surface. The inner surface of the hollow tube defines a conduit extending longitudinally along the length of the hollow tube, for example, the conduit can extend longitudinally along the overall length of the hollow tube.

Herein, the phrase "engaged around the hollow tube" means engaged around the outer surface of the hollow tube.

The helically wound sheet of material may be a sheet of material extending helically about the longitudinal axis of the element such that the helically wound sheet of material partially overlaps itself at successive points along the longitudinal length of the element.

The helically wound sheet of material may be wound about the longitudinal axis of the element, for example, helically wound about the longitudinal axis of the element at an oblique angle to the longitudinal axis of the element.

A portion of the helically wound sheet of material overlaps itself on each consecutive helical turn such that there are no gaps between the turns. It will be appreciated that there are no gaps between consecutive helical turns and that the shape of the helically wound sheet of material is substantially tubular (e.g., tubular, i.e., the helically wound sheet of material forms the hollow tube). Thus, the helically wound sheet of material overlaps itself at consecutive points along the longitudinal length of the hollow tube.

The applicants of this case have found that the hollow tube comprising a spirally wound sheet of material having partially overlapping spiral turns will not collapse or deform under the weight of the layer comprising filler material and the cladding material bonded around the layer. The applicants of this case have also found that the hollow tube has a consistent wall thickness and a uniform final appearance that can help prevent counterfeiting.

The average wall thickness of the hollow tube may be 0.2 to 3.0 mm, e.g., 0.5 to 2.5 mm, e.g., 1.0 to 2.0 mm, e.g., 1.3 to 1.5 mm. The wall thickness is defined herein as the distance between the outer surface and the inner surface of the hollow tube.

The inner diameter of the hollow tube may be 1.5 to 10 mm, for example, 2.0 to 9.0 mm, for example, 3.0 to 8.0 mm, for example, 4.0 to 7.0 mm, for example, 5.0 mm or 6.0 mm. The inner diameter is defined herein as the distance between opposite points of the diameter on the inner surface at the widest point of the tube.

The hollow tube may comprise 1-10 material sheets, for example, 1, 2, 3, 4, 5, 6, 7, 9 or 10 material sheets. The hollow tube may comprise at least 2 material sheets, for example, at least 3 material sheets, for example, at least 4 material sheets.

Preferably, the sheet of material of the hollow tube is paper. The paper may comprise plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper may be formed from plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper may be filter paper or cellulose/lyocell/viscose fiber-based paper.

Preferably, the sheet of material of the hollow tube is a plug wrap.

The sheet of material of the hollow tube may have a thickness of 0.02 to 1.5 mm, such as 0.1 to 1.2 mm, such as 0.2 to 1.0 mm, such as 0.3 to 0.8 mm, such as 0.5 mm or 0.6 mm.

The sheet of material of the hollow tube may have a basis weight of 24 to 200 grams per square meter (g/m2), such as 45 to 180 g/m2, such as 60 to 160 g/m2, such as 100 to 120 g/m2.

The hollow tube may be colored. The material sheet of the hollow tube may be colored.

Preferably, the material sheet of the hollow tube is a material strip. The material sheet of the hollow tube (e.g., material strip) can have a width of 10 to 20 mm, e.g., 12 to 18 mm, e.g., 14 to 16 mm, e.g., 15 mm.

The applicants herein have discovered that an embolic covering having a basis weight of 24 to 200 grams per square meter (g/m2) can be spirally wound and formed into a hollow tube which will not collapse or deform under the weight of the layer containing the filler material and the covering material joined around the layer.

The material sheet of the hollow tube may be air permeable. The air permeability of the material sheet of the hollow tube paper (or wrapping material) is measured in CORESTA air permeability units (CU). The CORESTA unit is defined as the volume flow rate (cubic centimeters per minute) of air passing through a 1 square centimeter substrate sample under an applied pressure difference of 1 kiloPascal. The air permeability of the material sheet of the hollow tube may be 20 to 6000 CORESTA, for example, 1000 to 5000 CORESTA, for example, 2000 to 4000 CORESTA.

The sheet of material of the hollow tube may include an adhesive layer disposed on a surface of the sheet of material. When spirally wound, the adhesive layer may be disposed on a portion of the sheet of material and overlap itself on each consecutive spiral rotation. The adhesive layer may be used to secure a first portion of the spirally wound sheet of material to a second portion of the spirally wound sheet of material of the consecutive spiral rotations. The adhesive layer may be used to secure the hollow tube together. The adhesive layer may include an adhesive strip disposed at an edge of the sheet of material, for example, a continuous strip of adhesive. The adhesive layer may include adhesive dots disposed at an edge of the sheet of material. The adhesive may be a hot melt or water based adhesive as known in the art (eg, ethyl vinyl acetate).

The hollow tube may include an adhesive layer disposed on the outer surface of the hollow tube. The adhesive layer may be used to secure the layer containing the filling material to the hollow tube. The adhesive layer may include a strip of adhesive disposed along the longitudinal length of the hollow tube, for example, a continuous strip of adhesive. Optionally, the adhesive may include dots of adhesive disposed along the longitudinal length of the hollow tube. The adhesive may be a hot melt or water-based adhesive as known in the art (e.g., ethyl vinyl acetate).

The layer comprising the filling material may be joined along the longitudinal length of the hollow tube, for example, along the entire longitudinal length of the hollow tube. The layer comprising the filling material may be joined concentrically around the hollow tube. The layer comprising the filling material may be the same length as the hollow tube.

The filling material may be gathered (eg, wrapped, eg, spirally wound) around the hollow tube.

The layer comprising filling material may comprise 1 to 10 filling material sheets, for example, 1, 2, 3, 4, 5, 6, 7, 9 or 10 sheets. The layer comprising filling material may comprise at least 2 filling material sheets, for example, at least 3 filling material sheets, for example, at least 4 filling material sheets.

The sheet of filler material may be gathered (eg, wrapped, eg, spirally wound) around the hollow tube.

In a specific example, the layer comprising the filling material may comprise a sheet of filling material joined concentrically around the hollow tube. The sheet of filling material may be wrapped around the hollow tube around the longitudinal axis of the hollow tube. The sheet of filling material may be wrapped at a 90 degree angle to the longitudinal axis of the hollow tube. The sheet of filling material may be wrapped around the hollow tube once around the longitudinal axis of the hollow tube so that the sheet of filling material circumscribes the hollow tube once and forms a single continuous layer of filling material around the hollow tube. In this embodiment, it will be appreciated that the width of the sheet of filling material will be approximately the same as the circumference of the hollow tube so that the sheet of filling material does not overlap or substantially overlap itself when wrapped around the hollow tube.

In a specific example where the layer containing the filling material comprises two or more thin sheets of the filling material, each thin sheet of the filling material may be continuously wrapped around the longitudinal axis of the hollow tube once, so that each thin sheet of the filling material circumscribes the hollow tube once and wraps around the hollow tube to form multiple layers of the filling material. Each thin sheet of the filling material may wrap around the longitudinal axis of the hollow tube at a 90 degree angle. The multiple layers of the filling material may be concentrically joined around the hollow tube.

Optionally, the sheet of filling material may be wrapped around the hollow tube more than once, such that the sheet of filling material circumscribes the hollow tube more than once (ie, overlaps itself) and forms multiple layers of filling material around the hollow tube.

In a further specific example, the sheet of filling material may be helically wound around the hollow tube, for example, helically wound around the longitudinal axis of the hollow tube at an oblique angle to the longitudinal axis of the hollow tube.

The helically wound sheet of filling material may have partially overlapping helical turns, whereby a portion of the helically wound sheet of filling material overlaps itself on each consecutive helical turn such that there are no gaps between turns. It will be appreciated that there are no gaps between consecutive helical turns and the helically wound sheet of filling material forms a continuous layer of filling material around the hollow tube.

The helically wound sheet of filling material may have adjacent non-overlapping helical turns whereby opposing edges of the helically wound sheet of filling material are adjacent along the length of the consecutive helical turns such that the consecutive helical turns are adjacent with no gaps between the turns.

The filler material sheet may have a basis weight of 16 to 200 grams per square meter (g/m2), such as 20 to 160 g/m2, such as 40 to 120 g/m2, such as 60 to 100 g/m2, such as 80 to 90 g/m2.

The sheet of filling material may have a width of 10 to 90 mm, such as 20 to 80 mm, such as 50 to 60 mm, such as 20 to 30 mm, such as 25 mm.

The sheet of filling material may include an adhesive layer disposed on one surface thereof. The adhesive layer may be used to secure the sheet of filling material around the hollow tube. The adhesive layer may include a strip of adhesive disposed at the edge of the sheet of filling material, for example, a continuous strip of adhesive. Optionally, the adhesive layer may include dots of adhesive disposed at the edge of the sheet of filling material. The adhesive may be a hot melt or water-based adhesive as known in the art (e.g., ethyl vinyl acetate).

The layer comprising filling material may have an average thickness of 0.2 to 3.0 mm, e.g., 0.3 to 2.5 mm, e.g., 0.4 to 2.0 mm, e.g., 0.5 to 1.5 mm, e.g., 0.8 to 1.4 mm, e.g., 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm. The thickness is defined herein as the shortest distance between a point on the outer surface of the hollow tube and a point on the cladding material joined around the layer comprising filling material. It will be appreciated that the thickness of the layer comprising filling material may not be constant, as the filling material overlaps as it is gathered (e.g., wrapped, e.g., spirally wound) around the hollow tube, and thus the thickness of the layer comprising filling material is an average value.

The filling material may have a filtering effect on an aerosol (e.g., vapor) or tobacco smoke as it is inhaled through the element. The filling material may include a filtering material. The filling material may be a filtering material. The term "filtering material" as used herein means any material that has a filtering effect on an aerosol (e.g., vapor) or tobacco smoke when inhaled through the element. In certain embodiments, the elements of the present invention have zero or substantially zero filtering effect on an aerosol (e.g., vapor) or tobacco smoke. In this case, the element of the present invention can allow aerosol or tobacco smoke from the tobacco segment to easily pass into other elements of the aerosol generating product or smoking product without substantially retaining the aerosol or tobacco smoke by the element. In other embodiments, the element of the present invention can have an aerosol (e.g., vapor) or tobacco smoke filtering effect.

The filling material may be paper or a nonwoven material. The paper or nonwoven material may comprise plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper or nonwoven material may be formed from plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper or nonwoven material may be an airlaid material, a filter paper or a cellulose/lyocell/viscose fiber-based paper.

Preferably, the layer comprising the filling material does not comprise cellulose acetate. Preferably, the filling material is not cellulose acetate.

The applicants of this case have discovered that incorporating an air-laid material directly into a layer bonded around the hollow tube has desirable filtering and/or cooling properties on aerosols (e.g., vapor) or tobacco smoke. The applicants of this case have also discovered that the air-laid material can provide a layer with a consistent thickness and a uniform final appearance that can help prevent counterfeiting.

The filling material may be embossed. Optionally, the filling material may not be embossed.

The sheathing material may be joined around the layer comprising filling material along the longitudinal length of the layer comprising filling material, for example, along the full longitudinal length of the layer comprising filling material. The sheathing material may be joined concentrically around the layer comprising filling material. The sheathing material may be the same length as the layer comprising filling material, which in turn may be the same length as the hollow tube. Thus, the hollow tube, the layer comprising filling material and the sheathing material may all have the same length.

The cover material may have a basis weight of 24 to 200 grams per square meter (g/m 2 ), such as 45 to 180 g/m 2 , such as 60 to 160 g/m 2 , such as 100 to 120 g/m 2 .

The air permeability of the covering material may be 20 to 6000 CORESTA, such as 1000 to 5000 CORESTA, such as 2000 to 4000 CORESTA.

The coating material may be paper, for example, breathable paper. Preferably, the coating material is an embolic coating material. The coating material may be coated, for example, with starch, guar gum and/or a hydrophobic coating. The coating material may function to properly hold the filling material layer around the hollow tube.

The covering material may be secured around the layer containing the filling material using an adhesive, for example, by overlapping and gluing seams as is known in the art.

The applicants of this case have found that a plug wrap having a basis weight of 100 to 160 g/m2 can be assembled around the layer including the filler material, and when combined with other components such as filter elements for use in aerosol generating products or smoking products, or when further processed into aerosol generating products such as heated tobacco or electronic cigarettes or smoking products such as cigarettes, it will not collapse or deform.

The length of the element is 5 to 150 mm, such as 10 to 100 mm, such as 50 to 90 mm, such as 12 to 23 mm, such as 18 mm to 22 mm.

The element may have a circumference of 14 to 30 mm, for example 16 to 25 mm, for example 17 to 24 mm, for example 18 mm to 22 mm, for example 19.8 mm, for example 24.25 mm.

The element may have a hardness of 90% to 97%, such as 91% to 97%, such as 92% to 97%, such as 94%, 95% or 96%.

In this context, hardness is a measure of the degree of deformation of the component after a provided pressure is applied for a provided time. The hardness is measured using a Cerulean QTM Module 7 device. A preload is applied to the component and the contact diameter point (DP) is measured. A higher load is then applied and the depressed diameter (DL) is measured after a provided time or once the slope threshold is reached. The hardness is calculated as follows: %H = (DL/DP) x 100. The load cell used by the QTM Module 7 device is 290 grams.

The applicants of this case have found that the element of the present invention will not collapse or deform when combined with other elements used in aerosol generating products or smoking products, such as filter elements, or when further processed into aerosol generating products such as heated tobacco or electronic cigarettes or into smoking products such as cigarettes. The applicants of this case have also found that the structural integrity of the element can match other elements used in aerosol generating products or smoking products, such as those formed from cellulose acetate tows, so that the element of the present invention can be easily combined with further elements into a multi-segment product, such as a multi-segment filter.

The element may comprise a biodegradable material. Preferably, the element comprises exclusively a biodegradable material. The element may be biodegradable. Preferably, the element does not comprise cellulose acetate.

As used herein, biodegradable means capable of being broken down by living organisms such as bacteria and fungi.

The component or the material of the component has a biodegradability of at least 90% after 6 months under controlled composting conditions, as determined according to ISO 14855 Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions - Method by analysis of evolved carbon dioxide.

The element or the material of the element may be readily biodegradable. In this context, the term "ready biodegradable" means that the element has a degree of "ready biodegradability" of biodegradability, as measured according to OECD Test No. 301 B: Ready Biodegradability ( _{CO 2} Evolution (Modified Sturm Test)).

The applicants of the present case have discovered that by manufacturing the element from paper or other readily biodegradable materials, the element can provide the desired cooling and/or filtering properties on aerosols (e.g., vapor) or tobacco smoke while also being readily biodegradable.

In a further aspect of the invention, there is provided a multi-segment product for an aerosol generating product or a smoking product, for example a multi-segment filter, comprising a component according to any of the preceding descriptions and one or more independent further components.

In a further aspect of the present invention, there is provided an aerosol generating product or smoking product comprising the above-mentioned element or a multi-stage product comprising the above-mentioned element.

Herein, the aerosol generating product may include heated tobacco products, such as heat-not-burn devices, tobacco heating devices, and the like; and electronic cigarettes. Herein, the smoking product may include cigarettes, cigars, cigarillos, hand-rolled cigarettes, and the like.

The aerosol generating product or smoking product may include a multi-segment product or component as listed above, which is connected to a wrapped rod of smoking material, such as tobacco smoking material. The aerosol generating product or smoking product may further include an outer layer of a tipping wrapper, such as an outer layer of a tipping paper. The outer layer of the tipping wrapper is connected to the multi-segment product or component by being joined to the adjacent end of the wrapped rod of smoking material around the multi-segment product or component. The outer layer of the tipping wrapper may be assembled to leave some of the outer surface of the multi-segment product or component exposed. The multi-section product or component may be connected to the coated rod of smoking material by a full outer covering material, wherein the full outer covering material is joined around the entire length of the multi-section product or component and the adjacent end of the smoking material rod.

The applicants have discovered that an aerosol-generating or smoking product comprising an element according to the present invention may have a reduced staining appearance at the mouth end (i.e., the user's mouth end) compared to known (e.g., non-annular) elements or mouthpieces. The elements according to the present invention may also concentrate an aerosol such as vapor or tobacco smoke into an air stream directed toward the user's tongue. The applicants have also discovered that an element according to the present invention may provide cooling of the aerosol (e.g., vapor) or tobacco smoke. The applicant has also found that the element according to the present invention can allow aerosol (e.g., vapor) or tobacco smoke from the tobacco segment to easily pass into other elements of the aerosol-producing product without the aerosol (e.g., vapor) or tobacco smoke being substantially retained by the element. The applicant has also found that the element according to the present invention can act as a reservoir where the aerosol or tobacco smoke from the tobacco segment is concentrated, for example, in the conduit of the hollow tube. The applicant has also found that the element according to the present invention can also improve nicotine delivery to the user. The applicants of the present case have also discovered that the device according to the present invention can provide a filtering effect on aerosols (e.g., vapor) or tobacco smoke.

The multi-stage product, device, aerosol generating product or smoking product according to the present invention may be non-ventilated or may be ventilated by methods known in the art, for example, using a pre-perforated or breathable wrapper or outer wrapper (outer paper); and/or laser perforating the wrapper and/or outer wrapper. Similarly, ventilation of the entire outer wrapper (outer paper) may be inherently breathable or may be provided with ventilation holes, and for products where ventilation of both the wrapper and the outer wrapper (outer paper) exists, ventilation through the outer wrapper (outer paper) is typically aligned with ventilation through the wrapper. The vent holes through the wrapping material, through the outer wrapping material (outer paper), or through both can be made by laser drilling during device manufacturing.

In a further aspect of the invention, there is provided a multiple rod comprising a plurality of elements according to the invention, for example arranged end to end in a mirror image relationship.

In a further aspect of the present invention, there is provided a method for manufacturing an element for an aerosol generating product or a smoking product, the steps of which include: advancing a material sheet in a longitudinal direction; spirally winding the material sheet around a shaping rod so that the material sheet partially overlaps itself in continuous spiral rotations, thereby forming a longitudinally extending hollow tube; advancing a filling material in a longitudinal direction; gathering (e.g., wrapping, e.g., spirally winding) the filling material around the hollow tube to form a layer containing the filling material joined around the hollow tube; gathering (e.g., wrapping) and securing a wrapping material around the layer containing the filling material to form a continuous rod; and cutting the continuous rod to form individual elements.

The sheet of material can be advanced continuously.

The sheet of material may be pulled from a source (eg, a roll of material) before being advanced toward the shaping rod.

The method may comprise advancing 1-10 sheets of material, for example 1, 2, 3, 4, 5, 6, 7, 9 or 10 sheets of sheet material. The method may comprise advancing at least 2 sheets of material, for example at least 3 sheets of material, at least 4 sheets of material. In the case of two or more sheets of filler material, they may be drawn from two or more sources, such as two rolls of material.

The method may include applying an adhesive to the advancing material sheet. The adhesive may be applied to one surface of the advancing material sheet. The adhesive may be applied to the advancing material sheet before the advancing material sheet is spirally wound around the shaping rod. For example, the adhesive may be applied to the material sheet at an adhesive station before the advancing material sheet is spirally wound around the shaping rod. The adhesive may be sprayed onto the material sheet, for example, along the longitudinal edge of the material sheet, for example, sprayed onto one surface of the material sheet. The adhesive may be a hot melt or water-based adhesive as known in the art (e.g., ethyl vinyl acetate).

The adhesive may be applied to portions of the material sheet that will overlap with itself (eg, at successive spiral turns) as the material sheet is helically wrapped around the shaping rod.

The shaping rod may also be referred to as a spindle.

The shaping rod may be substantially cylindrical, for example, cylindrical.

The shaping rod may include an outer surface that defines the inner diameter of the hollow tube.

The shaping rod may have a diameter of 1.5 to 10 mm, for example 2.0 to 9.0 mm, for example 3.0 to 8.0 mm, for example 4.0 to 7.0 mm, for example 5.0 mm or 6.0 mm.

The inner diameter of the hollow tube may be 1.5 to 10 mm, for example, 2.0 to 9.0 mm, for example, 3.0 to 8.0 mm, for example, 4.0 to 7.0 mm, for example, 5.0 mm or 6.0 mm.

The sheet of material may have a width of 10 to 20 mm, such as 12 to 18 mm, such as 14 to 16 mm, such as 15 mm.

The material sheet is spirally wound around the outer surface of the shaping rod, for example, around the longitudinal axis of the shaping rod at an oblique angle to the longitudinal axis of the shaping rod. On each consecutive spiral rotation around the shaping rod, the first portion of the material sheet will partially overlap with the second portion of the material sheet, so that there is no gap between consecutive rotations of the material sheet. The overlapping portions of the material sheet can be secured to each other by an adhesive.

Preferably, the material sheet is paper. The paper may comprise plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper may be formed from plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper may be filter paper or cellulose/lyocell/viscose-based paper.

Preferably, the sheet of material is an embolic coating material.

The filling material can be advanced continuously.

The fill material may be pulled from a source before being advanced toward the longitudinally extending hollow tube.

The filling material is gathered (eg, wrapped, eg, spirally wound) around the hollow tube along the longitudinal length of the hollow tube, eg, along the entire longitudinal length of the hollow tube.

The filling material may be a filling material sheet.

The method may include advancing 1-10 sheets of filling material, for example, 1, 2, 3, 4, 5, 6, 7, 9 or 10 sheets of filling material. The method may include advancing at least 2 sheets of filling material, for example, at least 3 sheets of filling material, at least 4 sheets of filling material. In the case of two or more sheets of filling material, they may be pulled from two or more sources, such as two rolls of filling material.

The sheet of filling material may have a width of 10 to 90 mm, for example 20 to 80 mm, for example 50 to 60 mm, for example 20 to 30 mm, for example 25 mm. The sheet of filling material may be cut into a width of 60 to 90 mm.

The method may include the step of longitudinally cutting the sheet of filling material to thereby form two or more longitudinally extending sheets of filling material. For example, the cutting may occur at a cutting station before the sheet of filling material is advanced in the longitudinal direction and then gathered around the hollow tube. The two or more longitudinally extending sheets of filling material may be stacked on top of each other after cutting. The two or more longitudinally extending sheets of filling material may continue to be advanced in the longitudinal direction after cutting. The sheet of filling material may be cut to form two, three, four or more longitudinally extending sheets of filling material. Optionally, the filling material may be cut by a segmentation method and wound on a reel for use in the method of the present invention.

In a specific example, the sheet of filling material may be wrapped around the hollow tube around the longitudinal axis of the hollow tube. The sheet of filling material may be wrapped at a 90 degree angle to the longitudinal axis of the hollow tube. The sheet of filling material may be wrapped around the hollow tube once around the longitudinal axis of the hollow tube, so that the sheet of filling material circumscribes the hollow tube once and forms a single continuous layer of filling material around the hollow tube. Optionally, the sheet of filling material may be wrapped around the hollow tube more than once around the longitudinal axis of the hollow tube, so that the sheet of filling material circumscribes the hollow tube more than once (i.e., overlaps itself) and forms multiple layers around the hollow tube.

The sheet of filling material may be wrapped around the hollow tube in a gathering chamber for gathering (or assembling to gather) the sheet of filling material around the hollow tube. The sheet of filling material may be pulled into the gathering chamber, wherein the gathering chamber has an inlet for receiving the sheet of filling material and the hollow tube, and an outlet through which the hollow tube (and the filling material layer joined around the hollow tube) is led out of the gathering chamber. The gathering chamber may be a conical chamber with a larger inlet diameter than an outlet diameter.

In a specific example where the method includes advancing two or more sheets of filling material, the sheets of filling material may be stacked on top of each other to form a stack of two or more sheets of filling material. The stack of two or more sheets of filling material may be continuously wrapped around the hollow tube once around the longitudinal axis of the hollow tube, so that each sheet of filling material circumscribes the hollow tube once and forms multiple layers of filling material around the hollow tube. Each sheet of filling material may be wrapped at a 90 degree angle to the longitudinal axis of the hollow tube. The multiple layers of filling material may be concentrically joined around the hollow tube. The sheets of filling material may be wrapped around the hollow tube in a gathering chamber to gather (or be assembled to gather) the sheets of filling material around the hollow tube.

In a further specific example, the sheet of filling material may be helically wound around the hollow tube, for example, helically wound around the longitudinal axis of the hollow tube at an oblique angle to the longitudinal axis of the hollow tube.

Herein, the expression "wrapped around the hollow tube" means wrapped around the outer surface of the hollow tube.

The sheet of filling material may be wound helically around the hollow tube in a shaping chamber that is used (or assembled) to wind the sheet of filling material helically around the hollow tube. In some embodiments, the shaping chamber may include the shaping rod, wherein the sheet of material of the hollow tube may be wound helically around it to thereby form the longitudinally extending hollow tube before the sheet of filling material is wound helically around the hollow tube. The filling material sheet (and the material sheet of the hollow tube) can be pulled into the shaping chamber, wherein the shaping chamber has an input port for receiving the filling material sheet (and the material sheet of the hollow tube), and an output port through which the hollow tube (and the filling material layer joined around the hollow tube) is led out of the shaping chamber.

The sheet of filling material may be helically wound such that the sheet of filling material has partially overlapping helical turns, whereby a portion of the helically wound sheet of filling material overlaps itself on each consecutive helical turn, such that there are no gaps between turns, thereby forming a continuous layer of filling material around the hollow tube. Alternatively, the sheet of filling material may be helically wound such that the sheet of filling material has adjacent non-overlapping helical turns, whereby opposing edges of the helically wound sheet of filling material are adjacent along the length of the consecutive helical turns, such that the consecutive helical turns are adjacent and have no gaps between turns, thereby forming a continuous layer of filling material around the hollow tube.

The applicants of the present case have discovered that helically winding the filling material around the hollow tube provides a uniform layer containing the filling material having a substantially uniform wall thickness.

The method may further include applying an adhesive to the advancing sheet of filling material before the advancing sheet of filling material is spirally wound around the longitudinally extending hollow tube. The adhesive may be applied to the sheet of filling material at an adhesive station before the advancing sheet of filling material is spirally wound around the hollow tube. The adhesive may be sprayed onto the sheet of filling material, for example, on a surface of the sheet of filling material, for example, at an edge of the sheet of filling material. The adhesive may be used to secure the sheet of filling material around the hollow tube. The adhesive may be a hot melt or water-based adhesive as known in the art (e.g., ethyl vinyl acetate).

The filling material may be paper or a nonwoven material. The paper or nonwoven material may comprise plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper or nonwoven material may be formed from plant-based fibers, for example, one or more of linen, hemp, jute, ramie, abaca, cotton, coconut, bamboo, starch or wood pulp. The paper or nonwoven material may be an airlaid material, a filter paper or a cellulose/lyocell/viscose fiber-based paper.

A covering is wrapped around the layer containing the filling material. The covering can be wrapped using standard methods known in the art, such as a garniture unit. The covering can be secured around the layer containing the filling material using an adhesive, for example, by overlapping and gluing seams as known in the art.

The continuous rod can be cut in cross section to form individual components. The continuous extension rod can be cut using standard cutting methods known in the art, such as a rotating drum cutter. The continuous rod can be cut at a further cutting station.

In a further aspect of the present invention, there is provided a device for an aerosol generating product formed by a method according to any of the above descriptions.

In a further aspect of the present invention, there is provided a component for a smoking product formed by a method according to any of the above descriptions.

FIG. 1 shows a perspective view of a device 100 for use in aerosol generating products such as heated tobacco or electronic cigarettes, or in smoking products such as cigarettes, according to an embodiment of the present invention.

The element 100 comprises a longitudinally extending hollow tube 101, a layer 102 comprising a filler material joined about the hollow tube 101, and a wrapping material 103 joined about the layer 102. The hollow tube 101 comprises a helically wound sheet of material, which may be a strip of embolic wrapping material having a width of 15 mm and a basis weight of 120 g/m2, although it will be appreciated that other materials are also suitable. The helically wound sheet of material has partially overlapping helical turns (not shown) and forms the hollow tube 101. The helically wound sheet of material extends helically about the longitudinal axis of the element 100 such that the sheet of material partially overlaps itself at successive points along the longitudinal length of the hollow tube 101. The continuous rotations of the spirally wound material sheet can be secured to each other and therefore to the hollow tube 101 by a layer of adhesive (not shown) arranged on the surface of the spirally wound material sheet. The layer containing the filling material can comprise a sheet of air-laid nonwoven material with a width of 15 mm, but it will be appreciated that other filling materials are also suitable. The sheet of filling material is wrapped once around the hollow tube 101 and secured to the hollow tube 101 and the covering material 103 by adhesive lines (not shown) on the hollow tube 101 and on the covering material 103. The filling material can be embossed. The covering material 103 is an embolic covering material with a basis weight of 100 g/m2 and an air permeability of 20 to 6000 CORESTA. The element 100 has a length of 108 mm and a circumference of 24.5 mm.

FIG2 shows a cross-sectional view of the element 100 as shown in FIG1 along the line A-A. The cross section of the element 100 is annular. The inner diameter of the hollow tube 101 is shown by d and the average thickness of the layer 102 containing the filling material is shown by t. The layer 102 of the filling material has an average thickness of 1.3 mm. The inner diameter of the hollow tube 101 is 6 mm and the average wall thickness of the hollow tube 101 is 0.6 mm.

FIG3 shows a perspective view of an element 300 for use in an aerosol generating product or smoking product according to an embodiment of the present invention. The element 300 comprises a longitudinally extending hollow tube 301, a layer 302 comprising a filler material joined around the hollow tube 301, and a wrapping material 303 joined around the layer 302. The hollow tube 301 comprises a spirally wound sheet of material 304, which may be a strip of embolic wrapping material having a width of 15 mm and a basis weight of 100 g/m2, although it will be appreciated that other materials are also suitable. A portion of the spirally wound sheet of material 304 overlaps itself on each successive rotation so that there is no gap between rotations. The spirally wound material sheet 304 forms the hollow tube 301. The successive turns of the spirally wound material sheet 304 may be secured to one another using a layer of adhesive (not shown) disposed on the surface of the material sheet 304. The adhesive is applied to the portion of the material sheet 304 that overlaps itself (e.g., at successive spiral turns) and is thereby secured to the hollow tube 301. The layer 302 comprising the filling material may comprise a sheet 305 of air-laid nonwoven material having a width of 15 mm, however it will be appreciated that other filling materials are also suitable. The sheet of filling material 305 is helically wound around the hollow tube 301 and adjoins non-overlapping helical turns, whereby opposing edges of the helically wound sheet of filling material 305 are adjoined along the length of the consecutive turns so that there are no gaps between the turns. Thus, the helically wound sheet of filling material 305 forms a continuous layer of filling material 302 around the hollow tube 301. The helically wound sheet of filling material 305 is secured to the hollow tube 301 and the cladding material 303 by lines of adhesive (not shown) on the hollow tube 301 and lines of adhesive (not shown) on the cladding material 303. The wrapping material 303 is a plug wrapping material having a basis weight of 100 g/m2 secured with a line of adhesive (not shown) around the layer 302 containing the filling material.

FIG4 shows a schematic overview of the method of the invention. The component 300 can be manufactured by the method shown in FIG4.

A sheet of embolic coating material 306 having a width of 15 mm and a basis weight of 100 g/m2 is pulled out from a roll 307 and continuously advanced in the longitudinal direction L. At an adhesive station 308, the adhesive is sprayed along the longitudinal edge onto the surface of the advanced embolic coating material 306. The embolic coating material 306 is continuously advanced toward a shaping chamber 309 including a cylindrical shaping rod (mandrel) (not shown) having a diameter of 5.0 mm. The plug coating material sheet 306 is drawn into the shaping chamber 309 through an inlet and spirally wound around the shaping rod, so that the plug coating material sheet 306 partially overlaps itself in continuous spiral rotations, and the overlapping portions of the plug coating material sheet are secured to each other by the adhesive, thereby forming a longitudinally extending hollow tube with an inner diameter of about 5.0 mm. The air-laid nonwoven filling material sheet 310 with a width of 15 mm is drawn out from the reel 311 and continuously advanced in the longitudinal direction L. The filling material sheet 310 is pulled into the shaping chamber 309 through an input port and spirally wound around the hollow tube and adjacent to the non-overlapping spiral turns, whereby the opposite edges of the spirally wound filling material sheet are adjacent along the length of the continuous turns to form a continuous layer around the hollow tube. The hollow tube (and the filling material layer joined around the hollow tube) 312 are led out of the shaping chamber 309 through an output port. At the decoration unit 313, the plug coating material 315 with a basis weight of 100 g/m2 is pulled out from the reel 311 and wrapped around the layer containing the filling material (and the hollow tube) 312 and fixed with an adhesive to form a continuous rod 316. The continuous rod 316 is cut at a cutting station 317 to form individual components 300.

FIG5 shows a perspective view of an element 400 for use in an aerosol generating product or in a smoking product according to an embodiment of the invention. The element 400 comprises a longitudinally extending hollow tube 401, a layer 402 comprising a filler material joined around the hollow tube 401, and a wrapping material 403 joined around the layer 402. The hollow tube 401 comprises a spirally wound sheet of material 404, which may be a strip of embolic wrapping material having a width of 15 mm and a basis weight of 100 g/m2, although it will be appreciated that other materials are also suitable. A portion of the spirally wound sheet of material 404 overlaps itself on each successive rotation so that there is no gap between the rotations. The spirally wound sheet of material 404 forms the hollow tube 401. The successive rotations of the spirally wound sheet of material 404 may be secured to one another using a layer of adhesive (not shown) disposed on a surface of the sheet of material 404. The adhesive is applied to portions of the sheet of material 404 that overlap with itself (e.g., at successive spiral rotations) and thereby secured to the hollow tube 401. The layer 402 comprising the filling material comprises four sheets of air-laid nonwoven material, however it will be appreciated that other filling materials are also suitable. Each sheet of filling material is wrapped once around the hollow tube 401 at a 90 degree angle to the longitudinal axis of the hollow tube, thereby forming multiple layers of filling material concentrically joined around the hollow tube 401. The layer 402 containing the filling material is fixed to the hollow tube 401 and the covering material 403 by means of adhesive lines (not shown) on the hollow tube 401 and on the covering material 403. The covering material 403 is an embolic covering material having a basis weight of 100 g/m2 fixed around the layer 402 containing the filling material with adhesive lines (not shown).

Figure 6 shows a schematic overview of the method of the invention. The component 400 according to Figure 5 can be produced by the method shown in Figure 6.

A plug coating material sheet 406 having a width of 15 mm and a basis weight of 100 g/m2 is pulled out from a roll 405 and advanced in the longitudinal direction L. At an adhesive station 407, an adhesive is sprayed onto the surface of the advanced plug coating material 406 along the longitudinal edge. The plug coating material sheet 406 is continuously advanced toward a cylindrical shaping rod (mandrel) 408 having a diameter of 5.0 mm. The plug wrap sheet 406 is spirally wound around the shaping rod 408 so that the plug wrap sheet 406 partially overlaps itself in continuous spiral rotations, and the overlapping portions of the plug wrap sheet 406 are secured to each other by an adhesive, thereby forming a longitudinally extending hollow tube 409 having an inner diameter of about 5.0 mm. The hollow tube 409 is pushed toward a gathering chamber 410 and is pulled into the gathering chamber 410 through an inlet. A 60 mm wide air-laid nonwoven filling material sheet 411 is pulled out from a reel 412. At the cutting station 413, the air-laid nonwoven filling material sheet 411 is cut longitudinally to form four longitudinally extending filling material sheets 415 with a width of 15 mm. The four filling material sheets 415 are stacked on top of each other and pushed toward the gathering chamber 410 in the longitudinal direction L. The stack of the four filling material sheets 415 is pulled into the gathering chamber 410 through an input port and wrapped around the hollow tube 409 once at a 90 degree angle to the longitudinal axis of the hollow tube, so that each filling material sheet circumscribes the hollow tube 409 once and forms a multi-layer filling material joined concentrically around the hollow tube 409. The hollow tube (and the filling material layer joined around the hollow tube) 416 is led out of the gathering chamber 410 through an outlet. The gathering chamber 410 is a conical chamber, wherein the diameter of the inlet is larger than the diameter of the outlet. The conical chamber helps the filling material to be compressed around the hollow tube. At the decoration unit 419, an embolic coating material 418 with a basis weight of 100 g/m2 is pulled out from a reel 417 and wrapped around the layer containing the filling material (and the hollow tube) 416 and fixed with an adhesive to form a continuous rod 420. The continuous rod 420 is cut at a cutting station 421 to form the individual element 400.

Any of the components illustrated in Figures 1 to 3 and 5 may form part of a multi-stage product, which is included in aerosol generating products such as heated tobacco or electronic cigarettes or in smoking products such as cigarettes. The components according to Figures 1 to 3 and 5 may be assembled into a multi-stage product, an aerosol generating product or a smoking product according to methods known in the art.

The aerosol generating product, such as heated tobacco, comprises a tobacco material rod, a heating element, a power source, one or more further filter segments and any of the components illustrated in the above Figures 1 to 3 and 5. The component may be arranged at the mouth end of the aerosol generating product (i.e., acting as a mouthpiece), and the one or more further filter segments may be arranged downstream of the heating element and tobacco rod.

During use, the heating element of the heated tobacco product heats the tobacco stick to form an aerosol. The aerosol then passes through one or more elements that may have the function of cooling or filtering the aerosol before passing through any of the elements illustrated in Figures 1 to 3 and 5 above and entering the user's mouth. The aerosol may also be filtered by the element, thereby reducing the concentration of certain compounds in the aerosol. The aerosol may also be cooled by the element, that is, the temperature of the aerosol is reduced as it passes along the length of the element.

100,300,400: Component 101,301,401,409: Hollow tube 102,302,402: Layer containing filling material 103,303,403: Wrapping material 304,404: Spirally wound sheet of material 305: Air-laid nonwoven sheet of material 306,406: Sheet of embolization wrapping material 307,311,314,405,412,417: Reel 308,407: Adhesion station 309: Shaping chamber 310,411: Air-laid nonwoven sheet of filling material 312,416: Hollow tube (and a layer of filling material joined around the hollow tube) 313,419: Decorative unit 315,418: Plug wrapping material 316,420: Continuous rod 317,413,421: Cutting station 408: Shaping rod 410: Aggregation chamber 415: Filling material sheet A-A: Line d: Inner diameter t: Average thickness L: Longitudinal direction

Now, preferred embodiments of the present invention will be described by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a component for an aerosol generating product or a smoking product according to the present invention.

FIG. 2 is a cross-sectional view of the element shown in FIG. 1 .

FIG. 3 is a perspective view of a component for an aerosol generating product or a smoking product according to the present invention.

FIG. 4 is a schematic diagram overview of the method of the present invention.

FIG. 5 is a perspective view of a component for an aerosol generating product or a smoking product according to the present invention.

FIG. 6 is a schematic diagram overview of the method of the present invention.

100: Components

101:Hollow tube

102: Layer containing filling material

103: Cladding material

A-A: Line

Claims (35)

An element for an aerosol generating product or a smoking product, comprising a longitudinally extending hollow tube; a layer comprising a filler material, wherein the layer is engaged around the hollow tube; and a wrapping material engaged around the layer, wherein the hollow tube comprises a helically wound sheet of material, and wherein the helically wound sheet of material has partially overlapping helical turns. An element for an aerosol generating product or a smoking product as claimed in claim 1, wherein the layer comprises a sheet of filling material wrapped around the hollow tube. As for the element for aerosol generating products or smoking products as claimed in claim 2, the filling material sheet is wrapped around the longitudinal axis of the hollow tube at an angle of 90 degrees. A component for an aerosol generating product or a smoking product as claimed in claim 3, wherein the filling material sheet is wrapped once around the hollow tube. An element for an aerosol generating product or a smoking product as claimed in claim 1, wherein the layer comprises a sheet of filling material spirally wound around the hollow tube. An element for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the layer comprises 1 to 10 sheets of filler material. A component for an aerosol generating product or a smoking product as claimed in any one of claims 2 to 6, wherein the basis weight of the filler material sheet is 16 to 200 grams per square meter (g/m2). A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the layer comprising the filling material has an average thickness of 0.2 to 3.0 mm. A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the filling material is a filter material. An element for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the filling material is paper or a nonwoven material. An element for an aerosol generating product or a smoking product as claimed in claim 10, wherein the paper or nonwoven material comprises plant-based fibers. A component for an aerosol generating product or a smoking product as claimed in claim 10 or 11, wherein the paper or nonwoven material is an air-laid material, a filter paper or a cellulose/lyocell/viscose fiber-based paper. A component for an aerosol generating article or a smoking article as claimed in any of the preceding claims, wherein the filling material is embossed. A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the average wall thickness of the hollow tube is 0.2 to 3.0 mm. A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the inner diameter of the hollow tube is 1.5 to 10 mm. An element for an aerosol generating article or a smoking article as claimed in any of the preceding claims, wherein the sheet of material of the hollow tube is paper. A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the sheet of material of the hollow tube has a thickness of 0.02 to 1.5 mm. A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the sheet of material of the hollow tube has a basis weight of 24 to 200 grams per square meter (g/m2). A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the sheet of material of the hollow tube is an embolic coating material. A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the material sheet of the hollow tube comprises an adhesive layer disposed on a surface of the material sheet. A component for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the wrapping material is an embolic wrapping material having a basis weight of 24 to 200 grams per square meter (g/m2). An element for an aerosol generating product or a smoking product as claimed in any of the preceding claims, wherein the length of the element is 5 to 150 mm. An element for an aerosol generating article or a smoking article as claimed in any of the preceding claims, wherein the circumference of the element is 14 to 30 mm. A multi-segments product for use in an aerosol generating product or a smoking product, comprising an element as claimed in any one of the preceding claims and one or more discrete further segments. An aerosol generating product or smoking product comprising an element as in any of the preceding claims, or a multi-segment product as in claim 24. A method for manufacturing an element for an aerosol generating product or a smoking product, the steps comprising: advancing a sheet of material in a longitudinal direction; spirally winding the sheet of material around a shaping rod so that the sheet of material partially overlaps itself in successive spiral rotations, thereby forming a longitudinally extending hollow tube; advancing a filling material in a longitudinal direction; gathering the filling material around the hollow tube to form a layer containing the filling material joined around the hollow tube; gathering and securing a coating material around the layer containing the filling material to form a continuous rod; and cutting the continuous rod to form individual elements. The method of claim 26, comprising the step of applying an adhesive to the advancing sheet of material. A method as claimed in claim 27, wherein overlapping portions of the material sheets are secured to each other by an adhesive. A method as in any one of claims 26 to 28, wherein the filling material is a sheet of filling material. The method of claim 26, comprising the step of longitudinally cutting the sheet of filling material to thereby form two or more longitudinally extending sheets of filling material. A method as claimed in claim 29 or 30, wherein the sheet of filling material is wrapped around the hollow tube. A method as claimed in claim 31, wherein the sheet of filling material is wrapped around the longitudinal axis of the hollow tube at an angle of 90 degrees. A method as in any one of claims 26 to 30, wherein the sheet of filler material is spirally wound around the outer surface of the hollow tube. A method as in claim 33, wherein the helically wound sheet of filler material partially overlaps itself on successive helical rotations. A method as in claim 34, wherein the helically wound sheet of filler material has adjacent non-overlapping helical turns.