RU2820236C2 - Method and device for production of corrugated web - Google Patents

Abstract

FIELD: smoking accessories; various technological processes.

SUBSTANCE: group of inventions relates to a method and a device for making a corrugated web from a polymer material for an aerosol-generating article, as well as to a reel containing said corrugated web. Method includes steps: polymer material granules are heated to form a polymer material melt, a polymer material web is formed from a polymer material melt and the web of polymer material is treated at high temperature to form a corrugated web of polymer material and the corrugated web of polymer material is wound on a reel. Device comprises: a container for heating granules of polymer material to form a melt of polymer material, roller, or extruder for processing of polymer material melt with formation of corrugated web from polymer material and winding device for winding of corrugated web from polymer material on reel.

EFFECT: obtaining a web from polymer material, which has properties of softness and plasticity, corrugation, and will tend to retain shape after cooling of the web from polymer material to ambient temperature.

15 cl, 12 dwg

Description

[0001] The present invention relates to a method and apparatus for producing corrugated web. In particular, the present invention relates to a method and apparatus for producing a corrugated web for an aerosol generating product.

[0002] Traditional cigarettes burn tobacco and reach temperatures that release volatile compounds. Temperatures in burning tobacco can reach over 800 degrees Celsius, and such high temperatures remove much of the water contained in the smoke released from the tobacco. Other aerosol-generating products are also known in the art in which the aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than burned. Examples of systems using aerosol-generating products include systems that heat a tobacco-containing substrate from 200 degrees Celsius to 400 degrees Celsius to generate an aerosol. Despite the lower aerosol generation temperature, the aerosol stream generated by such systems may have a higher perceived temperature than traditional cigarette smoke due to the higher moisture content compared to combustible smoking products.

[0003] Typically, aerosol generating articles contain a plurality of elements assembled into a rod. The plurality of elements typically comprise an aerosol-forming substrate and an aerosol-cooling element located within the rod downstream of the aerosol-forming substrate. The aerosol cooling element may alternatively be called a heat exchanger due to its functionality. One or both of the aerosol cooling element and the aerosol forming substrate may comprise a plurality of axial channels to provide air flow in an axial direction. A plurality of axial channels may be formed by a sheet that has been corrugated and assembled within a rod to form the channels. In such examples, the corrugated sheet is typically formed by corrugating a substantially continuous web and cutting a plurality of corrugated sheets from the corrugated and assembled web.

[0004] Methods and devices are known in the art for making corrugated fabric for use in an aerosol generating product. Known methods for making corrugated webs typically involve feeding a substantially continuous web between a pair of alternating rollers and applying multiple parallel, equally spaced longitudinally extending pleated corrugations to the continuous web. The corrugated web is then assembled using a rod making apparatus to form a continuous rod having a plurality of axial channels. The rod is then wrapped using a rod maker and cut into smaller segments to form an aerosol generating substrate or aerosol cooling element for the aerosol generating article.

[0005] However, such known methods require a large and expensive corrugator to be positioned in-line upstream of the core making apparatus, and a dedicated, separate corrugator is required for each core manufacturing apparatus in production. In turn, this leads to the need to increase the area of production premises to accommodate corrugating devices. Moreover, if the corrugation requires maintenance or is otherwise idle, the supply of corrugated web to the associated core making unit may be interrupted and may have to be stopped.

[0006] In addition, if the web is made of a polymeric material, such as, for example, polylactic acid (PLA), then the web will tend to return to a flatter configuration after corrugation, since webs made of polylactic acid have elastic properties when ambient temperatures of about 20 degrees Celsius, which is the normal temperature at which corrugating is carried out between a pair of corrugating rollers. Moreover, variability in web material and stoppage of the corrugator during processing can lead to defects in the corrugated web and scrap.

[0007] It would be desirable to provide a method and apparatus for making a corrugated web for an aerosol generating article that at least partially solves these problems.

[0008] In a first aspect, there is provided a method for manufacturing a corrugated web of a polymeric material for an aerosol generating article, comprising the steps of:

heating granules of polymeric material to form a melt of polymeric material;

forming a web of polymer material from a melt of polymer material and processing the web of polymer material at an elevated temperature to form a corrugated web of polymer material and

winding a corrugated sheet of polymer material onto a reel.

[0009] By treating the resin web at an elevated temperature when the resin web has soft and pliable properties, the corrugations formed in the resin web will tend to retain their shape well after the resin web has cooled to ambient temperature . Advantageously, the polymeric material is processed at a temperature corresponding to, above, or close to the glass transition temperature of the polymeric material.

[0010] The following describes a polylactic acid web by way of example. Although polylactic acid web may be the preferred polymer, the process described and the resulting product can be implemented using any other suitable polymer, such as polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, or cellulose acetate.

[0011] When using polymeric materials other than polylactic acid, such polymeric materials preferably have a glass transition temperature in the range of 20 degrees Celsius above or below the glass transition temperature of polylactic acid. For example, the polymer material is selected such that it has a glass transition temperature in the range of 40 degrees Celsius to 85 degrees Celsius. In an alternative or additional embodiment, such polymeric materials preferably have a melting point in the range of 50 degrees Celsius above or below the melting point of polylactic acid. For example, the polymer material is selected such that it has a melting point in the range of 123 degrees Celsius to 228 degrees Celsius.

[0012] The glass transition temperature of polylactic acid is approximately 60 to 65 degrees Celsius and the melting point is approximately 173 to 178 degrees Celsius. There is some variability between different polylactic acid samples when different plasticizers are used. In addition, the relative amounts of different stereoisomers in the polylactic acid melt can also influence the glass transition temperature and melting point. When the polylactic acid web is processed at temperatures equal to, above or near the glass transition temperature, the corrugations formed in the web will tend to harden after the polylactic acid web is cooled, thereby providing a corrugated web with reliable corrugation characteristics. Various angles, profiles and pitches of corrugations can be formed and secured in the polylactic acid web to provide different properties when used in aerosol cooling elements. This also applies to polymeric materials other than polylactic acid.

[0013] In prior art corrugating processes in which a polylactic acid web is corrugated between a pair of corrugated corrugating rollers at an ambient temperature of approximately 20 degrees Celsius (well below the glass transition temperature), the web will exhibit some degree of springback that will reduce the efficiency of the corrugation process. In contrast, it has been found that processing the polylactic acid web at elevated temperatures, when the web is in a soft and relatively pliable state, produces a more reliable result, and that the speed of the polylactic acid web does not affect corrugation stability to the same extent. This also applies to polymeric materials other than polylactic acid.

[0014] In addition, winding the corrugated web of polymeric material onto a bobbin allows the core maker to directly feed the corrugated web of polymeric material from the bobbin without the need to provide a corrugator adjacent to each core maker. This allows you to reduce the cost of equipment and the occupied production space.

[0015] Preferably, the corrugated web of polymeric material is cooled to below the glass transition temperature before being wound onto a bobbin. This helps reduce the risk of flattening of the corrugations while the corrugated sheet of polymer material is still soft and pliable. This may be accomplished by means of chill rollers, which may be made of a thermally conductive material, such as metal, and provided with internal passages for the passage of heat transfer fluid. In an alternative embodiment, a heat transfer fluid, such as cooled air, can be passed or blown across one or both surfaces of the corrugated web of polymeric material.

[0016] As used herein, the term "polylactic acid", also known as poly(lactic acid) or PLA, refers to a biodegradable aliphatic polyester containing the monomer shown below, which is well suited for single-use applications. Polylactic acid can be plasticized using various biocompatible plasticizers.

[0017] As used herein, the term “polylactic acid melt” refers to polylactic acid heated to a temperature above its melting point, causing it to be in a liquid state.

[0018] As used herein, the term “polymeric material” refers to polymeric materials including polylactic acid, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, and cellulose acetate.

[0019] As used herein, the term “melt polymer material” means a polymer material that has been heated to a temperature above its melting point, causing it to be in a liquid state.

[0020] As used herein, the term “elevated temperature” refers to a temperature significantly above normal room temperature. In some embodiments, the term "elevated temperature" means a temperature that is equal to, above, or slightly below the glass transition temperature of the polymer material used. For polylactic acid, the glass transition temperature is usually between 60 and 65 degrees Celsius.

[0021] As used herein, the term “glass transition temperature” is the temperature above which the polymeric material is in a relatively soft, rubbery state, and below which the polymeric material is in a relatively hard, glassy state.

[0022] As used herein, the term “processing” means performing at least a local change in the shape of a material, wherein the new shape is not planar, such as waves or corrugations, on a web of polymeric material while the material is at a temperature elevated above room temperature. Such changes in the shape of the material can be performed using corrugated rollers, extrusion dies, extrusion tanks or extrusion hoppers, rods, curved shafts, multiple rollers or other tools and devices, as well as combinations of the above tools and devices.

[0023] As used herein, the term “reel” refers to a shaft or cylinder, with or without end flanges, onto which a web of polymeric material is wound after being corrugated.

[0024] As used herein, the term “aerosol-generating article” refers to an article containing an aerosol-generating substrate capable of releasing volatile compounds that can form an aerosol, for example, as a result of heating, combustion, or a chemical reaction. As used herein, the term "aerosol-forming substrate" is used to describe a substrate capable of releasing volatile compounds that can form an aerosol. Aerosols generated from aerosol-forming substrates in aerosol-generating articles of the present invention may be visible or invisible, and may contain vapors (e.g., fine particles of gaseous substances that are typically liquid or solid at room temperature ), as well as gases and liquid droplets of condensed vapor.

[0025] As used herein, the term "aerosol cooling element" is used to describe an element having a large surface area and a specified draw resistance. In use, the aerosol generated by volatile compounds released from the aerosol-forming substrate is passed over and cooled by the aerosol cooling element before being inhaled by the user. Unlike filters and other mouthpieces with high draw resistance, aerosol cooling elements have low draw resistance. Chambers and cavities in an aerosol-generating product are also not considered to be aerosol cooling elements.

[0026] As used herein, the term “web” refers to a sheet element having a width and length substantially greater than its thickness.

[0027] As used herein, the term “grooved” means a sheet or web having a plurality of corrugations, folds or grooves oriented substantially parallel to each other or at least parallel to some other corrugations, folds or grooves.

[0028] As used herein, the term “corrugations” refers to a plurality of substantially parallel ridges consisting of alternating peaks and valleys connected by the side walls of the corrugations. These include, but are not limited to, corrugations having a square wave profile, a sine wave profile, a triangular profile, a sawtooth profile, or any combination thereof.

[0029] As used herein, the term “longitudinal direction” refers to a direction along or parallel to the length of the web or sheet.

[0030] As used herein, the term “width” refers to a direction perpendicular to the length of the web or sheet or, in the case of a roller, parallel to the axis of the roller.

[0031] As used herein, the term “pitch size” refers to the lateral distance between the dimples on either side of the top of a particular corrugation. As used herein, the terms “vary” and “vary” refer to deviations from standard manufacturing tolerances and, in particular, to values that differ from each other by at least 5 percent.

[0032] As used herein, the term “corrugated roller” refers to a roller with corrugations extending in a circumferential manner around the roller. When two corrugated rollers are positioned adjacent and parallel to each other such that their corrugations alternate or nearly touch each other, a flat web of polymeric material can be passed between the corrugated rollers to form corrugations thereon.

[0033] As used herein, the term “rod” refers to a generally cylindrical member with a substantially circular or oval cross-section.

[0034] As used herein, the terms “axial” or “in the axial direction” refer to a direction along or parallel to the axis of the cylinder forming the rod.

[0035] As used herein, the terms “assembled” or “assembled” mean that the web or sheet is folded or otherwise compressed or tapered in a substantially transverse direction relative to the axis of the cylinder forming the rod.

[0036] As used herein, the term "amplitude" refers to the height of the corrugation from its apex to the deepest point of the deepest, immediately adjacent valley.

[0037] As used herein, the term “corrugation angle” refers to the angle between the side surfaces of a particular corrugation.

[0038] Processing the web of polymeric material may include passing the web of polymeric material between at least two corrugated rollers to form a corrugated web of polymeric material.

[0039] In one embodiment, a melt of polymeric material is first passed between at least two smooth rollers to form a flat web of polymeric material, and then the flat web of polymeric material is passed between at least two corrugated rollers at an elevated temperature.

[0040] Preferably, the thickness of the flat web of polymeric material is from about 20 micrometers to about 200 micrometers, more preferably from about 30 micrometers to about 120 micrometers, most preferably from about 40 micrometers to about 80 millimeters.

[0041] In some embodiments, a web of polymeric material is passed between a plurality of sets of bellows, such as two sets of beads, three sets of beads, four sets of beads, or five sets of beads. Each set or pair of corrugated rollers may have a different corrugated depth or a different gap size (i.e., a different distance between the outer surfaces of adjacent corrugated rollers). For example, successive sets or pairs of corrugated rollers can have gradually decreasing gap sizes, which makes it possible to obtain very thin corrugated webs from polymeric materials. In some embodiments, each set or pair of corrugated rollers is configured to reduce the thickness of the web of polymeric material by a predetermined amount, for example, from 10 percent to 50 percent of the thickness of the polymeric material before passing between the corresponding set or pair of rollers.

[0042] In some embodiments, a melt of polymeric material is first passed between at least two smooth rollers to form a web of polymeric material, and then the web of polymeric material is passed through or between molding elements to corrugate the web of polymeric material at an elevated temperature. The forming elements can be in the form of rods, curved shafts or a plurality of bending rollers.

[0043] In some embodiments, forming a web of polymeric material from a melt of polymeric material and processing the web of polymeric material comprises extruding the melt of polymeric material through a grooved extrusion die to form a grooved web of polymeric material.

[0044] In these embodiments, a melt of polymeric material may be heated in a tank or hopper of an extruder and forced through a suitably configured die to form a corrugated web of polymeric material. The extrusion head may have an extrusion opening that defines the width, thickness, and cross-sectional profile of the corrugations of the corrugated web of polymeric material. For example, the extrusion hole may be a slot with a zigzag or wave-like configuration.

[0045] The corrugated web of polymeric material can be further passed through or between forming elements configured to form additional corrugations on the corrugated web of polymeric material at an elevated temperature. The forming elements can be in the form of rods, curved shafts or a plurality of bending rollers.

[0046] The elevated temperature may be a temperature that is higher than a temperature 20 degrees Celsius below the glass transition temperature of the polymeric material, optionally a temperature that is higher than a temperature 10 degrees Celsius below the glass transition temperature of the polymeric material, optionally a temperature that is higher than a temperature 5 degrees Celsius below the glass transition temperature of the polymer material, or optionally a temperature that is not less than the glass transition temperature of the polymer material. The glass transition temperature of polylactic acid is in the range of 60 to 65 degrees Celsius. The glass transition temperatures of other polymers can be determined from scientific literature or by experiment.

[0047] The corrugated web of polymeric material may have a zigzag corrugated profile with pointed peaks and valleys. In an alternative embodiment, the corrugated web of polymeric material may have a wavy, corrugated profile with curved peaks and valleys.

[0048] Preferably, the pitch values of substantially all corrugations are in the range of from about 0.5 millimeters (mm) to about 1.7 millimeters, preferably from about 0.7 mm to about 1.5 mm, and most preferably from about 0.9 mm to approximately 1.3 mm. This has been found to provide particularly satisfactory draw resistance values and uniformity when the corrugated web of polymeric material is assembled and wrapped to form an aerosol cooling element in an aerosol generating article.

[0049] In some embodiments, the corrugations may have a variable pitch across the width of the corrugated web of polymeric material. This can provide a number of advantages, including a more uniform distribution of channels in an aerosol cooling element made from an assembled corrugated web of polymeric material, since the corrugations on the assembled web will have less tendency to overlap and nest within each other.

[0050] The pitch size of most corrugations may be substantially the same across the entire width of the corrugated web of polymeric material, with a small number of corrugations, such as one or two, having a significantly different pitch or pitch sizes such that the pitch size of the corrugations varies across the width of the corrugated sheet made of polymer material.

[0051] In some embodiments, at least 10 percent of the corrugations have a pitch size that is different from the pitch size of at least one immediately adjacent corrugation. In other embodiments, at least 40 percent of the corrugations have a pitch size that is different from the pitch size of at least one immediately adjacent corrugation. In some embodiments, at least 70 percent of the corrugations have a pitch size that is different from the pitch size of at least one immediately adjacent corrugation. In some embodiments, all or substantially all of the corrugations of the corrugated web of polymeric material have a pitch value that is different from the pitch value of at least one immediately adjacent corrugation. This further reduces the risk of overlapping and nesting of corrugations on the assembled corrugated sheet of polymer material into each other.

[0052] The corrugation pitch value of the corrugated sheet of resin material may be any suitable value.

[0053] Each of at least some of the corrugations of the corrugated web of polymeric material may have an amplitude value that is different from the amplitude value of at least one immediately adjacent corrugation. In such embodiments, the amplitude values may be of any suitable value. For example, the amplitude values of the corrugations may vary from about 0.1 mm to about 1.5 mm, from about 0.2 mm to about 1 mm, or from about 0.35 mm to about 0.75 mm.

[0054] In an alternative or additional embodiment, to provide pitch sizes that vary across the width of the corrugated web of polymeric material, each of the at least several corrugations may have a corrugation angle that differs from the corrugation angle of at least one immediately adjacent corrugation. In such embodiments, the corrugation angles may be any suitable value. For example, the corrugation angles of corrugated webs of polymeric material can vary from about 30 degrees to about 90 degrees, from about 40 degrees to about 80 degrees, or from about 55 degrees to about 75 degrees.

[0055] One or more corrugations may be symmetrical about the radial direction. That is, the angle between each side surface of the corrugation and the radial direction or “side surface inclination angle” may be the same and equal to half the angle of the corrugation. In an alternative embodiment, one or more corrugations are asymmetrical with respect to the radial direction. That is, the angles of inclination of both side surfaces of the corrugation can be different.

[0056] One or more depressions between immediately adjacent corrugations may be symmetrical with respect to the radial direction. That is, the angle between the directly adjacent side surfaces of the immediately adjacent corrugations and the radial direction may be the same and equal to half the valley angle. In an alternative embodiment, one or more depressions between immediately adjacent corrugations may be asymmetrical with respect to the radial direction. That is, the angles of inclination of directly adjacent side surfaces forming the depression may be different.

[0057] In the case where the angles of the corrugations vary across the width of the corrugated web of polymeric material, the values of the amplitude of the corrugations may be substantially the same, or they may also vary across the width of the corrugated web of polymeric material. In the case where the corrugation amplitude values vary across the width of the corrugated web of polymeric material, the corrugation angles of the corrugations may be substantially the same, or they may also vary across the width of the corrugated web of polymeric material.

[0058] In a second aspect, a bobbin is provided containing a corrugated web of polymeric material formed by the method according to the first aspect wound on a bobbin.

[0059] Such a reel can be used to feed a corrugated web of polymeric material directly into a core making apparatus, for example for the manufacture of aerosol cooling elements, without the need for a linear corrugator.

[0060] In a third aspect, a method is provided for forming rod-shaped articles, comprising assembling a corrugated web of polymeric material into a substantially cylindrical strand by means of a bell, wrapping the strand into a wrapper to form a wrapped strand, and cutting the wrapped strand into rod-shaped segments, the corrugated web made of polymer material is unwound from a reel before assembly.

[0061] A corrugated web bobbin of resin material can be produced by the method according to the first aspect.

[0062] A fourth aspect provides an aerosol generating article comprising a rod-shaped article manufactured by the method of the third aspect.

[0063] In a fifth aspect, a device is provided for forming a corrugated web of polymeric material, comprising:

a container for heating granules of polymer material to form a melt of polymer material;

a roller or extruder for processing a melt of polymer material to form a corrugated web of polymer material and

winding device for winding corrugated fabric made of polymer material onto a reel.

[0064] In a sixth aspect, a rod making apparatus is provided, comprising a bell for assembling a corrugated web of polymeric material into a substantially cylindrical strand, a wrapping device for wrapping the strand to form a wrapped strand, and a cutting device for cutting the wrapped strand into rod-shaped segments, characterized in that the corrugated web of polymer material is collected from a reel on which the corrugated web of polymer material is wound.

[0065] The rod-shaped segments can be used as aerosol cooling elements in aerosol generating products.

[0066] The aerosol cooling element preferably offers little resistance to the passage of air through the rod. Preferably, the aerosol cooling element does not substantially affect the draw resistance of the aerosol generating article. Thus, it is preferable that there be a small low pressure difference from the upstream end of the aerosol cooling element to the downstream end of the aerosol cooling element. To achieve this, it is preferable that the axial porosity be greater than 50 percent and that the air flow path through the aerosol cooling element be relatively unobstructed. The porosity in the axial direction of the aerosol cooling element is determined by the ratio of the cross-sectional area of the material forming the aerosol cooling element to the internal cross-sectional area of the aerosol generating article in the part containing the aerosol cooling element.

[0067] The terms "upstream" or "downstream" may be used to describe the relative positions of the elements or components of the aerosol generating article. For simplicity, the terms "upstream" and "downstream" as used herein refer to the relative position along the rod of the aerosol generating article relative to the direction in which the aerosol is drawn through the rod.

[0068] It is desirable for the aerosol cooling element to have a large total surface area. Thus, in preferred embodiments, the aerosol cooling element is formed from a corrugated web of polymeric material assembled to form channels. In preferred embodiments, the aerosol cooling element is formed from an assembled corrugated web of polymeric material in accordance with any of the embodiments described above. In some embodiments, the aerosol cooling element may be formed from a corrugated web of polymeric material having a thickness of from about 5 micrometers to about 500 micrometers, such as from about 10 micrometers to about 250 micrometers. In some embodiments, the aerosol cooling element has a total surface area of from about 300 square millimeters per millimeter of length to about 1000 square millimeters per millimeter of length. In other words, for every millimeter of axial length, the aerosol cooling element has from about 300 square millimeters to about 1000 square millimeters of surface area. Preferably, the total surface area is approximately 500 square millimeters per millimeter of length.

[0069] The aerosol cooling element may be made of a material that has a specific surface area of from about 10 square millimeters per milligram to about 100 square millimeters per milligram. In some embodiments, the specific surface area may be approximately 35 square millimeters per milligram.

[0070] The specific surface area can be determined using a material having a known width and thickness. For example, the material may be a polymeric material having an average thickness of 50 micrometers with a variation of plus or minus 2 micrometers. In the case where the material also has a known width, for example from about 200 mm to about 250 mm, the specific surface area and density can be calculated.

[0071] If an aerosol containing a portion of water vapor is drawn through the aerosol cooling element, some of the water vapor may condense on the surfaces of the axial channels formed by the aerosol cooling element. If water condenses, it is preferable for droplets of condensed water to remain as droplets on the surface of the aerosol cooling element rather than being absorbed into the material forming the aerosol cooling element. Thus, it is preferable that the material forming the aerosol cooling element be substantially non-porous or substantially non-water absorbent.

[0072] The aerosol cooling element may have the function of reducing the temperature of the aerosol stream drawn through the element due to heat transfer. The aerosol components will interact with the aerosol cooling element and lose thermal energy.

[0073] The aerosol cooling element may have the function of reducing the temperature of the aerosol stream drawn through the element by undergoing a phase change that consumes thermal energy from the aerosol stream. For example, the material forming the aerosol cooling element may undergo a phase change, such as melting or glass transition, which requires the absorption of thermal energy. If the element is selected such that it undergoes said endothermic reaction at the temperature at which the aerosol enters the aerosol cooling element, then said reaction will consume thermal energy from the aerosol stream.

[0074] The aerosol cooling element may have the function of reducing the perceived temperature of the aerosol stream drawn through the element by allowing components, such as water vapor, to condense from the aerosol stream. Due to condensation, the aerosol flow may be drier after passing through the aerosol cooling element. In some embodiments, the water vapor content of the aerosol stream drawn through the aerosol cooling element may be reduced by about 20 percent to about 90 percent.

[0075] In some embodiments, the temperature of the aerosol stream as it is drawn through the aerosol cooling element can be reduced by more than 10 degrees Celsius. In some embodiments, the temperature of the aerosol stream as it is drawn through the aerosol cooling element may be reduced by more than 15 degrees Celsius or by more than 20 degrees Celsius.

[0076] As discussed above, the aerosol cooling element may be formed from a corrugated web of polymeric material that has been assembled into an element that defines a plurality of generally parallel channels that in some embodiments extend generally in the axial direction, although in other embodiments, they may extend in a different direction. In the cross-sectional profile of such an aerosol cooling element, the channels may be visible as randomly oriented.

[0077] The aerosol cooling element may comprise an outer tube or wrap that contains or defines parallel channels. For example, a flat sheet material that has been folded, gathered or folded can be wrapped with a wrapping material, such as Ficella, to form an aerosol cooling element. In some embodiments, the aerosol cooling element comprises a sheet of corrugated material assembled into a rod shape and bounded by a wrapper, such as a filter paper wrapper.

[0078] In some embodiments, the aerosol cooling element is in the form of a rod having a length of from about 7 mm to about 28 mm. For example, the aerosol cooling element may have a length of approximately 18 mm. In some embodiments, the aerosol cooling element may have a substantially circular cross-section and a diameter of from about 5 mm to about 10 mm. For example, the aerosol cooling element may have a diameter of approximately 7 mm.

[0079] In some embodiments, the water content of the aerosol is reduced as it is drawn through the aerosol cooling element.

[0080] The aerosol-generating article may be a heated aerosol-generating article, i.e., an aerosol-generating article containing an aerosol-forming substrate that must be heated, rather than burned, to release volatile compounds capable of forming an aerosol. The heated aerosol generating article may comprise integral heating means forming part of the aerosol generating article or may be configured to cooperate with an external heater forming part of a separate aerosol generating device.

[0081] The aerosol generating article may resemble a combustible smoking article such as a cigarette. The aerosol generating product may contain tobacco, for example, in the form of homogenized tobacco material. The aerosol-generating product may be disposable. In an alternative embodiment, the aerosol generating article is partially reusable and contains a renewable or replaceable aerosol generating substrate.

[0082] As used herein, the term “homogenized tobacco material” refers to a material obtained by agglomerating tobacco into particles.

[0083] The homogenized tobacco material may be in the form of a sheet. The homogenized tobacco material may have an aerosol forming agent content of greater than 5 percent on a dry weight basis. The homogenized tobacco material may alternatively have an aerosol forming agent content of from 5 to 30 wt. % based on dry weight. Sheets of homogenized tobacco material may be formed by agglomerating particulate tobacco obtained by grinding or otherwise crushing one or both of the tobacco leaf blade and tobacco leaf stems; in an alternative or additional embodiment, the sheets of homogenized tobacco material may contain one or more of tobacco dust, tobacco fines and other particulate tobacco by-products generated, for example, during the processing, handling and shipping of tobacco. The sheets of homogenized tobacco material may contain one or more internal binders, ie tobacco endogenous binders, one or more external binders, ie tobacco exogenous binders, or a combination thereof to promote agglomeration of the tobacco into the particles; in an alternative embodiment or additionally, the sheets of homogenized tobacco material may contain other additives, including, without limitation, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavoring agents, fillers, aqueous and non-aqueous solvents, and combinations thereof. The aerosol-forming substrate may be a solid aerosol-forming substrate. In an alternative embodiment, the aerosol-forming substrate may contain both solid and liquid components. The aerosol-forming substrate may comprise tobacco-containing material containing volatile tobacco aromatic compounds that are released from the substrate upon heating. In an alternative embodiment, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol-forming agent. Examples of suitable aerosol-forming substances are glycerin and propylene glycol.

[0084] If the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise, for example, one or more of the following: powder, granules, beads, grains, thin tubes, strips or sheets, containing one or more of the following: herbal leaves, tobacco leaves, tobacco stem fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco and blasted tobacco. The solid aerosol-forming substrate may be in loose form or may be provided in a suitable container or cartridge. For example, the aerosol-forming material of the solid aerosol-forming substrate may be enclosed within a paper or other wrapper and in the form of a plug. If the aerosol-forming substrate is in the form of a plug, then the entire plug, including any wrapper, is considered an aerosol-forming substrate.

[0085] Optionally, the solid aerosol-forming substrate may contain additional tobacco or non-tobacco volatile flavor compounds released when the solid aerosol-forming substrate is heated. The solid aerosol-forming substrate may also contain capsules that contain, for example, additional tobacco or non-tobacco volatile flavor compounds, and such capsules may melt when the solid aerosol-forming substrate is heated or otherwise release their contents, such as when pressure is applied , for example, when breaking a capsule or capsules manually.

[0086] The elements of the aerosol generating article are preferably combined by means of a suitable wrapper, such as cigarette paper. The cigarette paper may be any suitable material for wrapping the rod-shaped components of an aerosol generating article. Preferably, the cigarette paper supports and aligns the constituent elements of the aerosol generating article as the article is assembled and holds them in place within the rod. Suitable materials are well known in the art.

[0087] It may be particularly preferred that the aerosol cooling element be integral to a heated aerosol generating article with an aerosol generating substrate formed from or containing homogenized tobacco material. In such embodiments, preferably the aerosol-forming agent content of the heated tobacco material is greater than 5 percent on a dry weight basis. For example, the content of the aerosol-forming substance in the homogenized tobacco material may range from 5 to 30 wt. % based on dry weight. The aerosol generated from such aerosol-forming substrates may be perceived as too hot by the user, and the use of an aerosol cooling element with a large surface area and low draw resistance may reduce the perceived temperature of the aerosol to an acceptable level.

[0088] The aerosol generating article may have a substantially cylindrical shape. The aerosol generating article may be substantially oblong. The aerosol generating article may have a length and a circumference substantially perpendicular to the length. The aerosol-forming substrate may have a substantially cylindrical shape. The aerosol-forming substrate may be substantially oblong. The aerosol-forming substrate may also have a length and a circumference substantially perpendicular to the length. The aerosol-forming substrate may be positioned in the aerosol-generating device such that the length of the aerosol-forming substrate is substantially parallel to the direction of air flow in the aerosol-generating device. The aerosol cooling element may be substantially elongated.

[0089] The aerosol generating article may have an overall length of from about 30 mm to about 100 mm, preferably from about 35 mm to about 60 mm. The aerosol generating article may have an outer diameter of from about 5 mm to about 12 mm.

[0090] The aerosol generating article may include a filter or a mouthpiece, or both a filter and a mouthpiece. The filter may be located at the downstream end of the aerosol generating article. The filter may be a cellulose acetate filter plug. The filter in one embodiment has a length of approximately 7 mm, but can have a length of from about 5 mm to about 10 mm. The aerosol-generating article may include a separating element located downstream of the aerosol-generating substrate.

[0091] The aerosol generating article may have an overall length of approximately 45 mm. The aerosol generating article may have an outer diameter of approximately 7.2 mm. In addition, the aerosol-forming substrate may have a length of approximately 10 mm. In one embodiment, the aerosol-forming substrate may be approximately 12 mm in length. In addition, the diameter of the aerosol-forming substrate can be from about 5 mm to about 12 mm, preferably from about 6 mm to about 9 mm.

[0092] The features described in connection with one aspect of the present invention may also be applied to other aspects of the invention. The present invention will now be described by way of example only with reference to the accompanying drawings, in which:

in FIG. 1 shows a device known from the prior art for producing corrugated fabric;

in FIG. 2 shows a first embodiment of the present invention;

in FIG. 3 shows a reel on which a corrugated polylactic acid web is wound;

in FIG. 4 shows a cross section through a pair of forming rollers according to the embodiment shown in FIG. 2;

in FIG. 5 shows a cross section of an alternative forming roll;

in FIG. 6 shows a cross section of another alternative forming roll;

in FIG. 7 shows a second embodiment of the present invention;

in FIG. 8 shows a third embodiment of the present invention;

in FIG. 9 and FIG. 10 shows a fourth embodiment of the present invention;

in FIG. 11 shows a cross section of a corrugated sheet with a zigzag profile; And

in FIG. 12 shows a cross section of a corrugated sheet with a wavy profile.

[0093] In FIG. 1 shows a device 100 for producing corrugated fabric known in the art. The device 100 includes, among other components, a set of corrugated rollers 102 comprising a first roller and a second roller, each of which is grooved across its entire width. The set of corrugated rollers 102 is arranged such that the corrugations of the first roller substantially alternate with the corrugations of the second roller. The device 100 also includes a side web cutting mechanism 104, a reel 106 of polylactic acid web-shaped material 108, a drive and brake mechanism 110, and a tension mechanism 112. To control the device 100 during operation, control electronics 114 are provided.

[0094] In use, the drive and brake mechanism 110 feeds the web 108 longitudinally from the bobbin 106 onto a set of corrugating rollers 102 via a side web cutting mechanism 104, which cuts the web to the desired width. The tension mechanism 112 ensures that the web 108 is fed to the set of corrugated rollers 102 at the desired tension. Corrugating rollers 102 move the web 108 between alternating corrugations of the first and second rollers to apply multiple longitudinally extending pleated corrugations to the web 108. Thus, the web 108 is deformed by the corrugated rollers 102 to form a corrugated web 116. The corrugated web 116 can then be compactly assembled and used to form an aerosol cooling element or an aerosol generating substrate for an aerosol generating article, as discussed below. For example, corrugated web 116 may be compactly assembled by socket 118 and fed into core maker 120 to form a continuous core that is then cut into a plurality of core-shaped components, each containing an assembled corrugated sheet formed from the cut portion of the corrugated web. . It should be noted that the prior art apparatus 100 occupies a relatively large area and that any interruption in the operation of the corrugating rollers 102 will cause the downstream core making apparatus 120 to immediately stop. In addition, the temperature of the web 108 when it reaches the corrugated rollers 102 will be ambient or room temperature, typically about 20 degrees Celsius, which is substantially below the glass transition temperature of polylactic acid. Accordingly, the polylactic acid 108 web will tend to elastically resist the corrugating process. This results in a significant tendency to resist deformation, which in turn can result in significant restoring force and other stresses and strains in the corrugated material.

[0095] In FIG. 2 schematically shows a first embodiment of the present invention. A mass of 200 molten polylactic acid granules is formed by heating the granules to a temperature at least equal to the melting point of polylactic acid, which is from 173 to 178 degrees Celsius. This can be done in a heating tank in a manner known in the art. Molten polylactic acid is passed between a pair of smooth rollers 201 to form a substantially flat polylactic acid web 202, as is also known in the art. The substantially flat polylactic acid web 202, still at an elevated temperature, is then passed between a pair of forming rollers 203. Each of the forming rollers 203 has substantially parallel circumferential corrugations on its surface, and the corrugations of one forming roller 203 preferably alternate with those of the other forming roller 203. The forming rollers 203 create a corresponding corrugated profile of the polylactic acid web 202 while it is at an elevated temperature and thus still soft and relatively pliable, forming a corrugated polylactic acid web 204. The corrugated polylactic acid web 204 may then be passed through a set of tension rollers 205. The web is then cooled to a temperature sufficiently below the glass transition temperature of the polylactic acid to allow the corrugations in the web 204 to shrink or heat-set before the corrugated polylactic acid web 204 is wound onto bobbin 206. Once the bobbin 206 is completely wrapped with the ribbed polylactic acid web 204, the web 204 is cut to its width and the fully wound bobbin 206 is replaced with an empty bobbin onto which more fluted polylactic acid web 204 can then be wound. This process is repeated to produce bobbins 206 on which a corrugated polylactic acid web 204 is wound.

[0096] In FIG. 3 shows a bobbin 206 completely wrapped with a corrugated polylactic acid web 204. Such a reel 206 is used to feed directly into the core maker, thereby avoiding the need for an additional step of corrugating the web immediately prior to the core maker.

[0097] In FIG. 4 is a cross-sectional view of the grooved forming rollers 203 according to the embodiment shown in FIG. 2. Shown are first and second forming rolls 203, each of which is knurled across its width 1201 in a knurled area 124. In this example, the corrugation zone 124 extends around the entire circumference of each roller and extends substantially along the entire width 1201 of each roller. In an alternative embodiment, one or both rollers may be grooved in their width only around a portion of their circumference, or only along a portion of their length, or only around a portion of their circumference and only along a portion of their length. The first and second rollers 203 are arranged such that their axes are substantially parallel and such that their corrugations are substantially alternating. The distance 1202 between the axes of the first and second rollers 203 can be adjusted to control the gap between the corrugations of the first and second rollers 203 and thus the amplitude of the folded corrugations applied to the polylactic acid web passing between the set of rollers 203.

[0098] In FIG. 5 is a schematic cross-sectional view through a grooved forming roller 203 with an axis of rotation 230. The circumferential surface of the roller 203 is provided with a zigzag grooved profile 220, shown here on an enlarged scale. The zigzag profile 220 has pointed peaks and valleys.

[0099] In FIG. 6 is a schematic cross-sectional view through an alternative grooved forming roller 203 with an axis of rotation 230. The circumferential surface of the roller 203 is provided with a wave-like grooved profile 221, shown here on an enlarged scale. The wavy profile 221 has curved peaks and valleys.

[00100] The grooved profiles 220, 221 may be characterized by a substantially constant pitch and constant amplitude, or a substantially constant pitch and constant amplitude. In an alternative embodiment, the grooved profiles 220, 221 may have a variable pitch or a variable amplitude, or both a variable pitch and a variable amplitude. These variable pitch or amplitude may vary in a periodic or non-periodic manner.

[00101] In FIG. 7 schematically shows a second embodiment of the present invention. A mass of 200 molten polylactic acid granules is formed by heating the granules to a temperature at least equal to the melting point of polylactic acid, which is from 173 to 178 degrees Celsius. This can be done in a heating tank in a manner known in the art. The molten polylactic acid is passed directly between a pair of grooved rollers 203 of the type described in connection with the first embodiment. This results in the direct formation of a corrugated polylactic acid web 204 without the need for a pair of smooth rollers 201.

[00102] In FIG. 8 schematically shows a third embodiment of the present invention. A mass of 200 molten polylactic acid granules is formed by heating the granules to a temperature at least equal to the melting point of polylactic acid, which is from 173 to 178 degrees Celsius. This can be done in a heating tank in a manner known in the art. Molten polylactic acid is passed directly between a pair of smooth rollers 201 to form a substantially flat polylactic acid web 202, as is also known in the art. The substantially flat polylactic acid web 202, still at an elevated temperature, is then passed between a first pair of forming rollers 203. Each of the forming rollers 203 has substantially parallel circumferential corrugations on its surface, and the corrugations of one forming roller 203 preferably alternate with the corrugations. another forming roller 203. The forming rollers 203 create a corresponding first grooved profile of the polylactic acid web 202 while it is at an elevated temperature and accordingly still soft and relatively pliable, forming a grooved polylactic acid web 204. The soft and pliable polylactic acid web 204 is then passed between a second pair of forming rollers 210 and then between a third pair of forming rollers 211. Forming rollers 210 have a smaller corrugation pitch than the forming rollers 203, and forming rollers 211 have a smaller corrugation pitch than forming rollers 210. Thus, as schematically shown in FIG. 8, as it passes between the second and third pairs of forming rollers 210, 211, a knurling pattern is applied to the polylactic acid web 204 in gradually decreasing increments.

[00103] In FIG. 9 and FIG. 10 schematically shows a fourth embodiment of the present invention. A mass of 200 molten polylactic acid granules is formed by heating the granules to a temperature at least equal to the melting point of polylactic acid, which is from 173 to 178 degrees Celsius. This can be done in a heating tank in a manner known in the art. The molten polylactic acid is then forced through an extrusion tank 251 having an extrusion head 250 with an extrusion opening 252. The extrusion hole 252 has a corrugation pattern corresponding to the desired corrugation pattern of the extruded polylactic acid corrugated web 204, as shown in FIG. 10. Although a zigzag corrugation profile is shown here, other corrugation profiles such as wave profiles may be implemented.

[00104] In FIG. 11 shows a cross section of a corrugated polylactic acid web 204 having a zigzag profile with pointed peaks and valleys. By appropriate configuration of the corrugations in the forming rolls 203 or in the extrusion hole 252, various corrugation profile parameters can be set to desired values, including pitch 240, peak angle 241, valley angle 242, and amplitude 243. As mentioned previously, although any of , some or all of the parameters from pitch 240, peak angle 241, valley angle 242, and amplitude 243 may be constant, each of these values may also vary periodically or randomly across the width of the material. Such variability in some or all of these parameters may avoid nesting of the cavities within each other in the assembled rod.

[00105] In FIG. 12 shows a cross section of a corrugated polylactic acid web 204 having a wavy profile with rounded peaks and valleys. By appropriate configuration of the corrugations in the forming rolls 203 or in the extrusion hole 252, various parameters of the corrugation profile can be given desired values, including pitch 240, crest curvature 244, valley curvature 245, and amplitude 243.

[00106] Throughout the specification and claims in this application, the words “comprise” and “comprising” and variations thereof mean “including but not limited to” and are not intended to exclude (and do not exclude) other parts, additives, components , integers or stages. Throughout the specification and claims herein, the singular includes the plural unless the context requires otherwise. In particular, if the singular number is used, then this description should be considered to include the plural as well as the singular unless the context requires otherwise.

[00107] The features, integers, characteristics, compounds, chemicals or groups described with respect to a particular aspect, embodiment or example of the present invention are to be considered applicable to any other aspect, embodiment or example described herein, except excluding those incompatible with it. All features disclosed in this application (including any accompanying claims, abstract and drawings), and all steps of any method or process disclosed herein, may be combined in any combination, except combinations in which at least some of such features or stages (or features and stages) are mutually exclusive. The present invention is not limited to the details of any of the embodiments described above. The present invention extends to any new feature or any new combination of features disclosed in this specification (including any of the appended claims, abstract and drawings), or to any new step or any new combination of steps of any method or process disclosed herein.

[00108] The reader's attention is directed to all publications and documents that have been published in connection with this field of application contemporaneously or prior to this specification and are publicly available for review in conjunction with this specification, the contents of all such publications and documents being incorporated herein by links.

Claims (21)

1. A method for manufacturing a corrugated sheet from a polymer material for an aerosol-generating product, the method including the steps of: granules of polymer material are heated to form a melt of polymer material; forming a web of polymer material from a melt of the polymer material and treating the web of polymer material at an elevated temperature to form a corrugated web of polymer material; And a corrugated sheet of polymer material is wound onto a reel. 2. The method according to claim 1, characterized in that processing the web of polymeric material includes passing the web of polymeric material between at least two corrugated rollers to form a corrugated web of polymeric material. 3. The method according to claim 1, characterized in that the melt of the polymeric material is first passed between at least two smooth rollers to form a web of polymeric material, and the web of polymeric material is then passed between at least two corrugated rollers at an elevated temperature . 4. The method according to claim 3, characterized in that a web of polymer material is passed between several sets of corrugated rollers. 5. The method according to claim 1, characterized in that a melt of polymeric material is first passed between at least two smooth rollers to form a web of polymeric material, and wherein the web of polymeric material is then passed through or between forming elements configured to create corrugations on a sheet of polymer material at elevated temperatures. 6. The method according to claim 1, characterized in that forming a web of polymer material from a melt of polymer material and processing the web of polymer material includes extruding a melt of polymer material through an extrusion head with a corrugated profile to form a corrugated web of polymer material. 7. The method according to claim 6, characterized in that the corrugated web of polymer material is passed through or between forming elements configured to form additional corrugations on the corrugated web of polymer material at an elevated temperature. 8. A method as claimed in any one of the preceding claims, wherein the elevated temperature is a temperature that is higher than a temperature 20 degrees Celsius below the glass transition temperature of the polymer material, optionally a temperature that is higher than a temperature 10 degrees Celsius below the glass transition temperature of the polymer material , optionally, a temperature that is higher than a temperature 5 degrees Celsius below the glass transition temperature of the polymeric material, or, optionally, a temperature not less than the glass transition temperature of the polymeric material. 9. The method according to any of the previous paragraphs, characterized in that the corrugated sheet of polymer material has a zigzag corrugated profile with pointed peaks and valleys. 10. Method according to any one of paragraphs. 1-8, characterized in that the corrugated sheet of polymer material has a wavy corrugated profile with rounded tops and valleys. 11. Method according to any of the previous paragraphs, characterized in that the polymer material is polylactic acid. 12. Method according to any one of paragraphs. 1-10, characterized in that the polymer material is selected from the group consisting of: polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate and cellulose acetate. 13. Method according to any one of paragraphs. 1-10, characterized in that the polymer material has a glass transition temperature in the range from 40 to 85 degrees Celsius and a melting point in the range from 123 to 228 degrees Celsius. 14. A reel containing a corrugated sheet of polymer material formed by the method according to any one of paragraphs. 1-13, wound on the shaft. 15. A device for forming a corrugated sheet of polymer material, containing: a container for heating granules of polymer material to form a melt of polymer material; a roller or extruder for processing a melt of polymer material to form a corrugated web of polymer material; And winding device for winding corrugated fabric made of polymer material onto a reel.