Vapor generating articles containing cellulose ester films

Abstract

The steam generating article includes a plurality of segments assembled in the form of a rod. The segments include a steam forming segment and a steam cooling segment within the rod downstream of the steam forming segment. The steam cooling section includes a curled cellulose ester (CE) film. The curled CE film may comprise cellulose acetate propionate, perforations, or both.

Description

Technical Field

[0001] The present invention generally relates to steam generating articles, such as steam generating articles for heat-not-burn (HNB) tobacco products, and methods of making the same. The present invention more particularly relates to cellulose ester films for cooling the steam generated in those articles. Background Art

[0002] Typical HNB tobacco products include an electronic heating device and a specially designed tobacco unit. The electronic heating device heats rather than burns the tobacco in the tobacco unit to produce steam at a lower temperature than traditional tobacco products. The steam may contain nicotine and other compounds.

[0003] To use an HNB product, a consumer inserts a tobacco unit into a heating device, turns on the heating device, and inhales the vapor, mimicking the act of using a conventional tobacco product.

[0004] Some HNB products currently on the market include IQOS from Philip Morris International TM , Ploom from Japan Tobacco International TM TECH and glo from British American Tobacco TM .

[0005] Even though HNB tobacco products produce cooler vapor, the vapor can still have a temperature of up to 300° C. This vapor needs to be cooled before it can be comfortably inhaled by the user. Therefore, these HNB tobacco products typically also include a vapor cooling section made of various materials. However, the materials used for these existing vapor cooling sections have one or more disadvantages, such as low melting point, insufficient cooling, excessive pressure drop, insufficient hardness to withstand the assembly process, and high plasticizer loading.

[0006] With regard to plasticizers, some of them have low boiling points, which makes them susceptible to being released into the steam during use, thereby causing performance and / or health issues.

[0007] Therefore, there is a need in the art for a cooling section material that has a sufficiently high melting point to provide an appropriate vapor temperature drop, has a minimal pressure drop and sufficient hardness for processing, and requires little or no plasticizer.

[0008] The present invention addresses this need as well as other needs, which will become apparent from the following description and the appended claims. Summary of the invention

[0009] The invention is as described in the appended claims.

[0010] Briefly, in one aspect, the invention comprises a steam generating article comprising a plurality of segments assembled in the form of a rod. The segments comprise a steam forming segment and a steam cooling segment located within the rod downstream of the steam forming segment. The steam cooling segment comprises a curled cellulose ester (CE) film.

[0011] In one or more embodiments, the CE membrane comprises cellulose acetate propionate.

[0012] In one or more embodiments, the CE membrane is perforated.

[0013] In another aspect, the present invention includes a method of forming a steam generating article.

[0014] In one or more embodiments, the method comprises the following steps:

[0015] (a) combining cellulose ester (CE), a solvent, and optionally a plasticizer to form a dope;

[0016] (b) casting the casting solution and evaporating the solvent to form a CE membrane;

[0017] (c) curling the CE membrane to form a curled CE membrane;

[0018] (d) gathering and wrapping the rolled CE film into a rod shape to form a steam cooling section; and

[0019] (e) longitudinally aligning and wrapping the steam generating section with the steam cooling section to form a steam generating article.

[0020] In one or more embodiments, the method comprises the following steps:

[0021] (a) heating cellulose ester (CE) and optionally a plasticizer in an extruder to form a melt;

[0022] (b) extruding the melt through a die to form a CE film;

[0023] (c) curling the CE membrane to form a curled CE membrane;

[0024] (d) gathering and wrapping the rolled CE film into a rod shape to form a steam cooling section; and

[0025] (e) longitudinally aligning and wrapping the steam generating section with the steam cooling section to form a steam generating article.

[0026] In one or more embodiments, the method comprises the following steps:

[0027] (a) combining cellulose ester (CE), a solvent, and optionally a plasticizer to form a casting solution;

[0028] (b) casting the casting solution and evaporating the solvent to form a CE membrane;

[0029] (c) perforating the CE membrane to form a perforated CE membrane;

[0030] (d) rolling the perforated CE membrane to form a perforated and rolled CE membrane;

[0031] (e) gathering and wrapping the perforated and rolled CE membrane into a rod shape to form a steam cooling section; and

[0032] (f) longitudinally aligning and wrapping the steam generating section with the steam cooling section to form a steam generating article.

[0033] In one or more embodiments, the method comprises the following steps:

[0034] (a) heating cellulose ester (CE) and optionally a plasticizer in an extruder to form a melt;

[0035] (b) extruding the melt through a die to form a CE film;

[0036] (c) perforating the CE membrane to form a perforated CE membrane;

[0037] (d) rolling the perforated CE membrane to form a perforated and rolled CE membrane;

[0038] (e) gathering and wrapping the perforated and rolled CE membrane into a rod shape to form a steam cooling section; and

[0039] (f) longitudinally aligning and wrapping the steam generating section with the steam cooling section to form a steam generating article.

[0040] In one or more method embodiments, the CE comprises cellulose acetate propionate. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic cross-sectional view of an exemplary steam generating article according to the present invention.

[0042] Figure 2 is a schematic cross-sectional view of another exemplary steam generating article according to the present invention.

[0043] Figure 3 is a bar graph showing the temperature of the vapor immediately following a vapor cooling section containing various membrane materials during 12 pumpings. DETAILED DESCRIPTION

[0044] It has been surprisingly discovered that certain cellulose esters (CE) can be formed into films using only small amounts of plasticizers or no plasticizers at all, that such CE can have a melting point high enough to withstand the conditions inside HNB tobacco products during operation, and that films made from such CE can provide a suitable steam temperature drop with minimal pressure drop and sufficient hardness for processing into steam cooling sections for HNB tobacco products.

[0045] Steam generating products

[0046] In one aspect, the present invention includes a steam generating article comprising a plurality of segments assembled in the form of a rod. The segments include a steam forming segment and a steam cooling segment located downstream of the steam forming segment within the rod. The steam cooling segment includes a curled cellulose ester (CE) film.

[0047] The steam cooling section is designed to cool the steam generated by the steam forming section.

[0048] As used herein, the term "vapor" includes aerosols.

[0049] The term "rod" refers to a generally cylindrical element having a substantially circular, oval or elliptical radial cross-section.

[0050] The term "curl" or variations thereof refers to a plurality of corrugations or ridges. Preferably, the corrugations or ridges extend in a longitudinal direction relative to the rod when the steam generating article is assembled.

[0051] The terms "upstream" and "downstream" may be used to describe the relative positions of elements, sections or components of a steam generating article. For simplicity, the terms "upstream" and "downstream" refer to the relative positions along the rod of the steam generating article relative to the direction in which steam is drawn through the rod.

[0052] The segments of the steam generating article may be assembled from a suitable wrapping material, such as cigarette paper. The cigarette paper may be any suitable material for wrapping the components of a steam generating article in the form of a rod. When the article is assembled, the cigarette paper should grip the segments of the steam generating article and hold them in place within the rod.

[0053] The shape of the steam-generating article may be substantially cylindrical. The article may be substantially elongated. The article may have a length and a circumference substantially perpendicular to the length. Similarly, the shape of the steam-forming section may be substantially cylindrical. The steam-forming section may be substantially elongated. The steam-forming section may also have a length and a circumference substantially perpendicular to the length. The steam-forming section may be accommodated in the steam-generating article so that the length of the steam-forming section is substantially parallel to the direction of airflow in the steam-generating article. Similarly, the shape of the steam-cooling section may be substantially cylindrical. The steam-cooling section may be substantially elongated. The steam-cooling section may also have a length and a circumference substantially perpendicular to the length. The steam-cooling section may be accommodated in the steam-generating article so that the length of the steam-cooling section is substantially parallel to the direction of airflow in the steam-generating article.

[0054] The steam generating article may have any desired length and diameter. For example, the article may have an overall length of 30 mm to 100 mm. The article may have an outer diameter of 5 mm to 12 mm.

[0055] The steam generating article may further include a filter or a mouthpiece. The filter may be located downstream of the steam cooling section, for example at the downstream end of the steam generating article. The filter may be a cellulose acetate tow filter plug. The shape of the filter may be substantially cylindrical. The filter may be substantially elongated. The filter may have a length and a circumference substantially perpendicular to the length. The filter may be housed in the steam generating article so that the length of the filter is substantially parallel to the direction of airflow in the steam generating article. The filter may have any desired length and diameter. For example, the filter may have a length of 5 mm to 10 mm, for example 7 mm. The filter may have an outer diameter of 5 mm to 12 mm.

[0056] The steam generating article may include a spacer section located downstream of the steam generating section, for example, between the steam generating section and the steam cooling section within the rod. The spacer section may serve one or more functions, such as (a) positioning the steam generating section toward the upstream end of the steam generating article so that it can contact the heating unit, (b) preventing the steam generating section from being pushed along the rod toward the steam cooling element when the heating unit is inserted into the steam generating section, and (c) providing a buffer zone between the steam generating section and the steam cooling section. The spacer section may be a hollow tube made of cellulose acetate.

[0057] Steam generation section

[0058] Steam formation section can comprise solid steam formation substrate.Alternatively, steam formation section can comprise both solid and liquid components.Steam formation substrate can comprise tobacco material containing volatile tobacco flavor compounds released from substrate when heated.Alternatively, steam formation substrate can contain non-tobacco material.Steam formation substrate can also comprise one or more steam forming agents.The example of steam forming agent comprises glycerine and propylene glycol.

[0059] Solid steam forms the substrate and can be in the form of powder, granules, granules, fragments, thin strips, strips and / or sheets containing herb leaves, tobacco leaves, tobacco tendon fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco and / or expanded tobacco. Solid steam forms the substrate and can be in loose form, or can be provided in a suitable container or barrel. For example, solid steam forms the substrate and can be contained in paper or other wrapping materials, and can have the form of a plug. When the steam forms the substrate and is in the form of a plug, the entire plug including any wrapping materials can be considered to be a steam-forming section.

[0060] Solid steam forms a substrate that can include additional tobacco and / or non-tobacco volatile flavor compounds released when heated. Solid steam forms a substrate that can include a capsule containing, for example, additional tobacco and / or non-tobacco volatile flavor compounds. Such capsules can melt during the heating of the substrate.

[0061] The solid vapor forms a matrix which can be provided on or embedded in a heat stable carrier. The carrier can be in the form of a powder, granules, pellets, fragments, thin strips, strips and / or a film. The solid vapor forms a matrix which can be deposited on the surface of the carrier in the form of, for example, a film, foam, gel and / or a slurry. The solid vapor forms a matrix which can be deposited on the entire surface of the carrier, or alternatively can be deposited in a pattern to provide uneven flavor delivery during use.

[0062] The steam-forming section may have the shape of a rod.

[0063] The steam-forming section may have a substantially circular radial cross-section.

[0064] The steam forming section may have a diameter of 5 mm to 10 mm.

[0065] Steam cooling section

[0066] The main function of the steam cooling section is to reduce the temperature of the steam produced by the steam forming section to a user's comfort level (eg 40°C to 60°C) without inducing excessive pressure drop. Cooling can be achieved in several ways.

[0067] For example, a steam cooling section may act as a heat sink to cool the temperature of steam drawn through the section by heat transfer. Components of the steam may interact with the steam cooling section and release thermal energy.

[0068] The steam cooling section may also cool the temperature of the steam drawn through the section by undergoing a phase change that absorbs thermal energy from the steam flow. For example, the material forming the steam cooling section may undergo a phase change that requires the absorption of thermal energy, such as a melting or glass transition.

[0069] The steam cooling section can also reduce the perceived temperature of the steam drawn through the section by condensing components in the steam flow, such as water vapor. Due to condensation, the steam flow may be drier after passing through the steam cooling section. Due to the lower moisture content, the user may perceive the temperature of the steam as lower than its actual temperature.

[0070] The steam cooling section can be configured to cool the steam emitted from the steam forming section by at least 50°C, at least 60°C, at least 70°C, at least 80°C, at least 90°C or at least 100°C. The degree of cooling can be controlled in a variety of ways, including by adjusting the thickness and / or the number of curls of the CE film in the steam cooling section. Thinner films tend to be more flexible, which allows a higher curling frequency. For a given film weight, a higher curling frequency tends to provide a larger surface area to cool the steam. Higher film weights can also produce better cooling.

[0071] In addition to cooling, the steam cooling section can also be used as a filter to remove moisture from the steam (contributing to the cooling effect) as well as unwanted phenolic compounds (e.g., phenol and cresol). Phenolic compounds can be adsorbed by the CE membrane and also absorbed by water droplets condensed on the CE membrane.

[0072] The steam cooling section can have a 300mm 2 / mmLength up to 1000mm 2 / total surface area of ​​mm length.

[0073] The steam cooling section preferably provides low resistance to air passing through the rod. The steam cooling section preferably does not substantially affect the draw resistance of the steam generating article. Preferably, there is a low pressure drop from the upstream end of the steam cooling section to the downstream end of the steam cooling section.

[0074] Low pressure drop can be achieved through a higher porosity vapor cooling section. The porosity of the vapor cooling section can be increased by reducing membrane weight, reducing membrane surface area, or both.

[0075] In one or more embodiments, the steam cooling section may have a porosity of 30% to 96%, 50% to 80%, or 60% to 70% in the longitudinal direction. The longitudinal porosity may be defined by the ratio of the cross-sectional area of ​​the material forming the steam cooling section to the internal cross-sectional area of ​​the steam generating article at the portion containing the steam cooling section.

[0076] The steam cooling segment can be formed from a rolled CE film by gathering and wrapping the film into segments defining a plurality of longitudinally extending channels. A radial cross-sectional profile of the steam cooling segment can show that the channels are randomly oriented.

[0077] The vapor cooling section may include an outer tube or wrapping material containing or positioning longitudinally extending channels. For example, a rolled CE membrane may be wrapped in a wrapping material (such as filter paper) to form a vapor cooling section.

[0078] The steam cooling section may have the shape of a rod.

[0079] The steam cooling section may have a length in the range of 5 to 50 mm, 5 to 40 mm, 5 to 30 mm, or 7 to 28 mm.

[0080] The steam cooling section may have a substantially circular cross-section and a diameter of 5 mm to 10 mm.

[0081] The steam cooling section may have a circumference in the range of 23 to 25 mm, 18 to 23 mm or 16 to 18 mm.

[0082] The steam cooling section should have a Filtrona hardness of at least 90% or at least 95% to survive in the combiner.

[0083] Preferably, the pressure drop from the steam cooling section is less than 100 mmWG, less than 80 mmWG or less than 40 mmWG.

[0084] In one or more embodiments, the temperature of the steam entering the steam cooling section can be as high as 210°C during puffs and as high as 130°C between puffs.

[0085] In one or more embodiments, the temperature of the steam exiting the steam cooling section can be in the range of 40°C to 60°C, or less than 50°C.

[0086] Cellulose ester film

[0087] The steam cooling section includes a curled cellulose ester (CE) film.

[0088] The cellulose ester may be cellulose acetate (CA), cellulose acetate propionate (CAP), or a mixture of the two.

[0089] Both materials have sufficiently high melting temperatures (e.g., >180°C, or >200°C) so that they are not easily melted by the heat of the steam during use. Film melting can cause the pores in the steam cooling section to narrow or close, thereby negatively affecting the pressure drop and / or cooling efficiency of the steam cooling section.

[0090] In one or more embodiments, the CE film comprises CA. Based on the total weight of the CE film, the CE film may comprise 50 wt % to 100 wt %, 50 wt % to 99 wt %, 50 wt % to 98 wt %, 50 wt % to 97 wt %, 50 wt % to 96 wt %, 50 wt % to 95 wt %, 50 wt % to 94 wt %, 50 wt % to 93 wt %, 50 wt % to 92 wt %, 50 wt % to 91 wt %, or 50 wt % to 90 wt % of CA. The balance of the CE film may comprise CAP and / or one or more additives.

[0091] In one or more embodiments, the CE membrane comprises CAP. Based on the total weight of the CE membrane, the CE membrane may comprise 50 wt % to 100 wt %, 50 wt % to 99 wt %, 50 wt % to 98 wt %, 50 wt % to 97 wt %, 50 wt % to 96 wt %, 50 wt % to 95 wt %, 50 wt % to 94 wt %, 50 wt % to 93 wt %, 50 wt % to 92 wt %, 50 wt % to 91 wt %, or 50 wt % to 90 wt % of CAP. The balance of the CE membrane may comprise CA and / or one or more additives.

[0092] CAP is a more flexible material than CA, so no plasticizer is needed when the film comprises CAP, especially in an amount greater than 50 wt%, greater than 60 wt%, greater than 70 wt%, greater than 80 wt%, greater than 90 wt% or greater than 95 wt% based on the total weight of the CE film.

[0093] When used in conjunction with a steam cooling stage, cellulose acetate refers to cellulose diacetate. CA may have a degree of substitution (DS) (ie, the average number of substituents per anhydroglucose monomer unit) of 2 to 2.6.

[0094] The CAP may have a DS of acetate from 0.1 to 1, 0.1 to 0.5, or 0.1 to 0.3. The CAP may have a DS of propionate from 2 to 2.9, 2.1 to 2.8, or 2.3 to 2.7.

[0095] CE can be produced by any method known in the art. Examples of methods for producing CE are taught in Kirk-Othmer, Encyclopedia of Chemical Technology, 5th Edition, Volume 5, Wiley-Interscience, New York (2004), pages 394-444. Cellulose, the starting material for producing cellulose esters, can be obtained in different grades and sources, such as from cotton linters, softwood pulp, hardwood pulp, corn fiber and other agricultural sources, and bacterial cellulose, etc.

[0096] One method of producing CE includes esterifying cellulose by mixing cellulose with one or more acetylating agents and an acidic catalyst. The cellulose is then converted into a cellulose triester. After esterifying the cellulose to the triester, a portion of the acyl substituents may be removed by hydrolysis or by alcoholysis to obtain a secondary cellulose ester, which may then be filtered to remove any gel particles or fibers. Water is then added to the mixture to precipitate the cellulose ester. The cellulose ester may then be washed with water to remove reaction by-products, followed by dehydration and drying.

[0097] The term "cellulose triester" includes cellulose esters that are not fully substituted with acyl groups. For example, the cellulose triester may have a DS of 2.85 to 2.95.

[0098] Depending on the method used, the distribution of acyl substituents can be random or non-random. Secondary cellulose esters can also be prepared directly without hydrolysis / alcoholysis by using limited amounts of acetylating agents. The latter method is particularly useful when the reaction is carried out in a solvent that will dissolve cellulose.

[0099] The acetylating agent may be a carboxylic acid, an anhydride and / or a carboxylic acid halide (particularly a carboxylic acid chloride). The carboxylic acid may be acetic acid, propionic acid or a mixture thereof. The anhydride may be acetic anhydride, propionic anhydride or a mixture thereof. The acyl chloride may be acetyl chloride, propionyl chloride or a mixture thereof.

[0100] Acidic catalysts that can be used to promote the esterification of cellulose generally include sulfuric acid or a mixture of sulfuric acid and at least one other acid. Other acidic catalysts that do not contain sulfuric acid can be similarly used to promote the esterification reaction. In the case of sulfuric acid, at least some of the hydroxyl groups in the cellulose can be initially functionalized as sulfate esters during the esterification reaction. As discussed above, once thoroughly esterified, the cellulose can be subjected to a controlled partial deesterification step.

[0101] The cellulose ester may have a number average molecular weight in the range of 30,000 amu to 100,000 amu or 50,000 amu to 80,000 amu. Unless otherwise specified, all molecular weights described herein are number average molecular weights. CE may be provided in the form of pellets, granules, powders or flakes.

[0102] Blends of different molecular weight cellulose esters can be used. For example, a blend of high molecular weight CE (e.g., CE with a molecular weight greater than 60,000 amu) can be blended with low molecular weight CE (e.g., CE with a molecular weight less than 60,000 amu). The weight ratio of high molecular weight CE to low molecular weight CE can vary, such as 1:10 to 10:1, 1:5 to 5:1, or 1:3 to 3:1.

[0103] The CE may have a polydispersity index of 2 to 4, 1.5 to 2.5, 1.75 to 2.25, or 1.8 to 2.2.

[0104] The cellulose esters described herein may be formed into films and used in a steam cooling stage.

[0105] In addition to the cellulose ester, the CE film may contain one or more additives, such as plasticizers, processing aids, and / or release agents.

[0106] Plasticizers are compounds that lower the glass transition temperature, melt viscosity, and / or elastic modulus of CE, making the plasticized CE easier to melt process.

[0107] A variety of plasticizers are known to be used to plasticize CE. If used, food grade plasticizers should be preferred, as some plasticizers may be banned for use in inhalation products in some jurisdictions. For example, phthalates, phosphorus, and chlorinated plasticizers may be banned.

[0108] As used herein, the term "food grade" refers to materials that have been approved for contact with food (directly or indirectly). Such materials may be classified as such if they meet the requirements of the United States Pharmacopeia ("USP grade"), the National Formulary ("NF grade"), and / or the Food Chemical Codex ("FCC grade") as of April 30, 2017.

[0109] Examples of food grade plasticizers include triacetin, diacetin, tripropionin, trimethyl citrate, triethyl citrate, tributyl citrate, eugenol, cinnamyl alcohol, alkyl lactones (e.g., γ-valerolactone), methoxyhydroxyacetophenone (acetyl vanillone), vanillin, ethyl vanillin, polyethylene glycol, 2-phenoxyethanol, glycol ethers, ethylene glycol ethers, propylene glycol ethers, polysorbate surfactants, sorbitan ester surfactants, polyethoxylated aromatic hydrocarbons, polyethoxylated fatty acids, polyethoxylated fatty alcohols, and combinations thereof.

[0110] If used, the amount of plasticizer can be selected to (i) lower the glass transition temperature of the CE (e.g., too low a plasticizer content may not lower the glass transition temperature enough to allow melt processing) and (ii) maintain the desired mechanical properties of the CE (e.g., too high a plasticizer content may reduce the tensile strength of the final composition).

[0111] In various embodiments, the CE film may contain up to 10 wt%, 0.1 wt% to 10 wt%, 1 wt% to 10 wt%, 5 wt% to 10 wt%, less than 0.5 wt%, less than 0.4 wt%, less than 0.3 wt%, less than 0.2 wt%, or less than 0.1 wt% of plasticizer based on the total weight of the CE film.

[0112] In one or more embodiments, the CE film does not contain a plasticizer.

[0113] The CE membrane may include a processing aid. If included, the processing aid may be present in an amount of 0.05 wt % to 10 wt %, 0.1 wt % to 5 wt %, or 0.5 wt % to 2.5 wt %, based on the total weight of the CE membrane. Examples of processing aids include titanium dioxide, aluminum oxide, zirconium oxide, silicon oxide (e.g., silicon dioxide), calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and mixtures thereof. The average particle size of the processing aid may vary. For example, the processing aid may have a volume average particle size of 0.01 to 50 μm, 0.02 to 40 μm, or 0.05 to 30 μm. The particle size may be determined, for example, by sieving analysis.

[0114] One or more release agents may be included to improve the strippability of the CE film from the backing sheet or substrate once formed. If included, the release agent may be present in an amount of 0.01 wt % to 10 wt %, 0.05 wt % to 5 wt %, 0.05 wt % to 1 wt %, or 0.05 wt % to 0.5 wt %, based on the total weight of the CE film. When the film is solvent cast, a release agent is typically included and added to the casting liquid. Typical release agents include fatty acids, such as stearic acid.

[0115] The CE membrane is curled to increase the surface area compared to membranes with smaller surface areas, thereby improving heat absorption.

[0116] The CE film may comprise a curl in a range of 5 to 65, 10 to 65, 15 to 65, 20 to 65, 5 to 60, 10 to 60, 15 to 60, 20 to 60, 5 to 55, 10 to 55, 15 to 55, 20 to 55, 5 to 50, 10 to 50, 15 to 50, 20 to 50, 5 to 45, 10 to 45, 15 to 45, 20 to 45, 5 to 40, 10 to 40, 15 to 40, 20 to 40, 5 to 35, 10 to 35, 15 to 35, 20 to 35, 5 to 30, 10 to 30, 15 to 30, 20 to 30, 5 to 25, 10 to 25, 15 to 25, 20 to 25, 5 to 20, 10 to 20, or 15 to 20 curls per inch (CPI).

[0117] The curl may have a height of 0.01 to 3 mm or 0.1 to 2 mm. As used herein, curl height refers to the distance between the peak and valley of the curl.

[0118] The CE membrane may have a thickness of 10 to 150 μm, 10 to 125 μm, 10 to 100 μm, 10 to 75 μm, 10 to 70 μm, 10 to 60 μm, 10 to 50 μm, 10 to 40 μm, 10 to 30 μm, 10 to 20 μm, 20 to 150 μm, 20 to 125 μm, 20 to 100 μm, 20 to 75 μm, 20 to 70 μm, 20 to 60 μm, 20 to 50 μm, 20 to 40 μm, 20 to 30 μm, 30 to 150 μm, 30 to 125 μm, 30 to 100 μm, 30 to 75 μm, 30 to 70 μm, 30 to 60 The thickness of the film can be in the range of 10 to 20 μm, 10 to 20 μm, 15 to 30 μm, 20 to 40 μm, 30 to 50 μm, 30 to 40 μm, 40 to 150 μm, 40 to 125 μm, 40 to 100 μm, 40 to 75 μm, 40 to 70 μm, 40 to 60 μm, 40 to 50 μm, 50 to 150 μm, 50 to 125 μm, 50 to 100 μm, 50 to 75 μm, 50 to 70 μm, 50 to 60 μm, 60 to 150 μm, 60 to 125 μm, 60 to 100 μm, 60 to 75 μm, 60 to 70 μm, 70 to 150 μm, 70 to 125 μm, 70 to 100 μm or 70 to 75 μm.

[0119] The rolled CE film in the steam cooling section may have a curvature of 30 to 480 cm 2 or 72 to 330cm 2 The total surface area within the range.

[0120] Membrane porosity

[0121] In one or more embodiments, in addition to curling, the CE membrane can be porous. The pores can be micropores (pore size <2 nm), mesopores (pore size 2 to 50 nm) and / or macropores (pore size >50 nm). Porous CE membranes tend to appear white or opaque to the naked eye and weigh less than non-porous CE membranes.

[0122] The pores can be chemically created by solvent casting of CE from a casting solution followed by quenching the film in a non-solvent such as water. After drying the film, the evaporated non-solvent leaves pores in the film.

[0123] In one or more embodiments, the rolled CE membrane comprises micropores.

[0124] In one or more other embodiments, the rolled CE membrane contains no pores.

[0125] In one or more other embodiments, the rolled CE membrane is free of micropores.

[0126] CE membranes with few or no pores tend to appear transparent to the naked eye and are denser than porous CE membranes.

[0127] Membrane perforation

[0128] In one or more embodiments, in addition to curling, the CE film may also have perforations. In contrast to holes, perforations refer to mechanically formed openings or holes in the CE film, such as by punching, cutting, piercing, and the like.

[0129] The perforations may have a diameter of 0.1 to 10 mm. The perforation diameter refers to the longest straight line distance between any two points on the perimeter of the opening or orifice in the CE membrane.

[0130] CE membranes can have anywhere from 1 to 100 perforations per square centimeter (p / cm 2 ), or 4 to 80p / cm 2 .

[0131] The perforations in the CE membrane may have a symmetrical shape, an asymmetrical shape, or both. Examples of symmetrical shapes include circles, semicircles, heart shapes, ovals, certain triangles (e.g., equilateral triangles, isosceles triangles), squares, rectangles, rhombuses, kites, isosceles trapezoids, regular pentagons, regular hexagons, regular heptagons, regular octagons, etc. Examples of asymmetrical shapes include certain triangles (e.g., Egyptian triangles, obtuse triangles, acute triangles), trapezoids, parallelograms, etc.

[0132] In one or more embodiments, the curled and perforated CE membrane may be free of chaff. Chaff refers to fragments of the CE membrane generated when the membrane is perforated. In the case of a chaff-free membrane, the chaff is completely separated from the CE membrane.

[0133] In one or more other embodiments, the curled and perforated CE membrane may include partially attached shading. Partially attached shading means that a portion of the shading remains attached or connected to the membrane. Partially attached shading may impart one or more advantages to the CE membrane, including providing increased surface area for cooling steam, more consistent flow, less pressure drop, and / or creating turbulence through the steam cooling section.

[0134] The partially attached crumbs may have a shape similar to a letter of the English alphabet, such as "C", "V", or "U".

[0135] When raised above the plane of the CE membrane or lowered below the plane of the CE membrane, the partially attached crumbs may be aligned perpendicular, parallel, or at an angle relative to the direction of steam flow through the steam cooling section.

[0136] CE membranes can be prepared by solvent casting or melt extrusion.

[0137] Solvent Casting

[0138] Methods for preparing CE films by solvent casting are known. Generally speaking, solvent casting methods involve combining CE and optional plasticizers, processing aids and / or release agents in a solvent to form a mixture known as a casting solution. Examples of suitable solvents include acetone, methylene chloride, ethyl lactate, methyl ethyl ketone and methylene chloride.

[0139] Solvent casting can be used to prepare CE films containing CA, CAP, or both. The casting liquid may or may not contain a plasticizer.

[0140] Typically, CA is added to the solvent in the form of flakes or powder, while CAP is added in the form of pellets. The casting solution is mixed until the CE is dissolved.

[0141] The casting liquid can then be cast onto a casting tape and dried to evaporate the solvent and obtain a film. Adding a release agent to the casting liquid can help remove the film from the casting tape. The film can be further dried and then curled using a curler.

[0142] One example of a crimper is a "stuffing box" or "stuffer box" crimper, in which a plurality of rollers are used to create friction, which causes the film to bend and form a curl. Other types of crimpers may also be used.

[0143] In the case of porous CE membranes, after removal from the casting tape, the membrane can be quenched in a non-solvent (eg, water), dried, and then rolled.

[0144] In the case of a perforated CE film, after the film is dried, it can be perforated, for example, by contacting the film with one or more perforating rollers, which impart holes or openings in the film. The perforating rollers can produce completely separated perforated chips, or more preferably, partially separated perforated chips. The perforated film can then be conveyed to a crimper for crimping.

[0145] If desired, during (a) the perforation step, (b) after the perforation step but before crimping, and / or (c) during the crimping step, the shavings may be removed from the film in the case of complete detachment, or lifted from the plane of the film in the case of partial detachment. Between the perforation and crimping steps, the perforated film may be passed over one or more additional rollers and / or over an air stream to remove or lift the shavings. Alternatively or additionally, the shavings may be removed or lifted from the plane of the film by the action of a crimping machine.

[0146] Melt extrusion

[0147] The CE and optional plasticizer and / or any other additives such as processing aids can be combined in a mixer or directly in an extruder. The CE can be in the form of flakes, powder or pellets.

[0148] The mixture is then heated in an extruder to form a melt. The melt is then extruded through a die (e.g., a flat die) to form a CE film. Optionally, the film can be wound through the nip of a chill roll set to perform thickness shaping and cooling. As described above, once cooled, the film can be curled or perforated in a curler and then curled.

[0149] Melt extrusion may be conducted at any suitable temperature, such as 165°C to 240°C, 200°C to 230°C, 210°C to 230°C, or 220°C to 230°C.

[0150] The extruder may be of any suitable type, such as an extruder equipped with a single screw or twin co-rotating screws.

[0151] One advantage of the present invention is that no plasticizer is required for melt extrusion of CE when the CE comprises CAP. This is not the case when the CE is only cellulose acetate.

[0152] Figure 1-Figure 2

[0153] Figure 1 A representative steam generating article according to the present invention is shown.

[0154] Figure 1 A heat-not-burn (HNT) tobacco unit 10 is depicted, comprising a tobacco segment 20, a cooling filter segment 30 and a cellulose acetate tow segment 40. These three elements are wrapped by paper 21, 31, 41 respectively, and then coaxially assembled into a rod 11 having a heating end 12 and a mouth end 13 by a wrapping paper 50.

[0155] Tobacco segment 20 may contain tobacco material in the form of leaf, paper or powder. During use, those materials are heated to at least 140° C. or more to release nicotine. As the heating temperature increases, for example, up to 240° C. or up to 300° C., more nicotine and other ingredients may be released.

[0156] After heating, when the user takes a puff of tobacco from the mouth end 13, the vapor generated in the tobacco segment 20 is cooled and filtered while passing through the cooling filter segment 30 and the cellulose acetate tow segment 40, and is finally inhaled by the user.

[0157] The cellulose acetate tow segment 40 as a mouthpiece provides a final appearance for the HNB tobacco unit 10. It can further filter the steam generated from the tobacco segment 20 through the cooling filter segment 30. In addition, the cellulose acetate tow mouthpiece 40 can also prevent the CE film or larger substances from the tobacco segment 20 from being sucked into the user's mouth.

[0158] Figure 2 Another representative steam generating article according to the present invention is shown.

[0159] Figure 2 The products shown are Figure 1 The article shown is similar except that it also includes a spacer section 60 (eg, a hollow cellulose acetate tube) and a wrapping paper 61 located between the tobacco section 20 and the cooling filter section 30 .

[0160] General Provisions

[0161] In order to eliminate any doubt, the present invention includes and explicitly contemplates and discloses any and all combinations of the embodiments, features, characteristics, parameters and / or ranges mentioned herein. That is, the subject matter of the present invention can be defined by any combination of the embodiments, features, characteristics, parameters and / or ranges mentioned herein.

[0162] Any ingredient, component or step not specifically named or identified as part of the invention is intended to be specifically excluded.

[0163] Any process / method, apparatus, article, compound, composition, embodiment, or component of the present invention may be modified by the transition terms "comprising," "consisting essentially of," or "consisting of," or variations of those terms.

[0164] As used herein, the indefinite article "a" or "an" means one or more than one, unless the context clearly indicates otherwise. Similarly, unless the context clearly indicates otherwise, the singular form of a noun also includes its plural form, and vice versa.

[0165] The conjunction "and / or" means any, some or all of the stated possibilities.

[0166] Although attempts have been made to be precise, the values ​​and ranges described herein can be considered approximate. These values ​​and ranges may vary from the values ​​they describe depending on the desired properties sought to be obtained by the present disclosure and the variations caused by standard deviations found in the measurement techniques. In addition, the ranges described herein are intended and specifically contemplated to include all subranges and values ​​within the ranges. For example, a range of 50 to 100 is intended to include all values ​​within that range, including subranges such as 60 to 90, 70 to 80, etc.

[0167] Any two numbers reporting the same property or parameter in the working examples may define a range. These numbers may be rounded to the nearest thousandth, hundredth, tenth, integer, ten, hundred or thousand to define a range.

[0168] The contents of all documents cited herein, including patents and non-patent literature, are hereby incorporated by reference in their entirety. If any incorporated subject matter contradicts any disclosure herein, the disclosure herein shall take precedence over the incorporated content.

[0169] The present invention can be further illustrated by the following working examples, which are included for illustrative purposes only and are not intended to limit the scope of the present invention.

[0170] Example

[0171] Examples 1-5

[0172] Cellulose ester films (curled CA and CAP films) with different thicknesses and loadings were used to prepare steam cooling segment samples. Both the CA film and the CAP film without plasticizer were prepared by solvent casting. The films were then manually curled and gathered into a rod shape and then placed in a pre-wrapped paper sleeve. The segment length of each sample was 27 mm.

[0173] CA membranes were made of Eastman cellulose acetate CA-394-60S (T m =240-260℃;MW n =60,000) or CA-398-30(T m =230-250℃;MW n =50,000).

[0174] CAP membrane by Eastman TREVA TM GC6021(T m =188-210℃).

[0175] The cooling section samples have the same inner diameter, length and wrapping paper parameters. The wrapping paper is 0.18mm thick.

[0176] Table 1 below lists the physical parameters of the membranes used.

[0177] Table 1. Some parameters of CA and CAP membranes used for 27 mm cooling section.

[0178]

[0179] The pressure drop and ventilation tester (CES 508) of Custom Electronics Systems, Inc. (Rural Hall, NC) was used to test the pressure drop of the steam cooling section samples and the Filtrona hardness thereof. Table 2 shows the physical parameters of the samples and the test results.

[0180] Table 2. Some parameters of the 27 mm cooling section formed by CA and CAP rolled films.

[0181]

[0182]

[0183] As seen in Table 2, segments using thinner CA membranes (Examples 1 and 3) require longer membrane loading (45 cm) to maintain segment stiffness. Because longer membranes are used, these membranes have greater surface area, but also higher pressure drop. Although greater membrane surface area will help lower the temperature of the steam, it can compromise pressure drop.

[0184] Examples 6-9 and references

[0185] Cellulose ester films (rolled CA and CAP films) with the same thickness were used to prepare steam cooling segment samples. Both CA and CAP films without plasticizer were prepared by solvent casting. The films were then manually rolled and gathered into a rod shape and then placed in a pre-wrapped paper sleeve. The segment length was 18 mm.

[0186] The CA films were made from Eastman cellulose acetate CA-394-60S and CA-398-30.

[0187] CAP membrane by Eastman TREVA TM GC6021 and CAP-482-20(T m =188-210℃).

[0188] The cooling section samples have the same inner diameter, length and wrapping paper parameters. The wrapping paper is 0.18mm thick.

[0189] The reference example contains a rolled film of polylactic acid (PLA) used in a Steam cooling section of heated tobacco unit.

[0190] Table 3 below lists the physical parameters of the membranes used.

[0191] Table 3. Some parameters of the membranes used for the 18 mm cooling section.

[0192]

[0193]

[0194] The pressure drop and ventilation tester (CES 508) of Custom Electronics Systems, Inc. (Rural Hall, NC) was used to test the pressure drop of the steam cooling section samples and the Filtrona hardness thereof. Table 4 shows the physical parameters of the samples and the test results.

[0195] Table 4. Some parameters of the 18 mm cooling section formed by the coiled film.

[0196]

[0197] The steam cooling sections of Examples 6-9 are assembled into Figure 2 The product comprises a 9 mm long cellulose acetate hollow tube 60 as a spacer.

[0198] The reference example in this study is a commercially available polylactic acid (PLA) rolled film made as a steam cooling section.

[0199] To compare the cooling effectiveness of CA and CAP films with that of PLA films, all fully heated rods were tested on a Borgwaldt LX20 linear smoking machine, using thermocouples to measure the vapor temperature between the vapor cooling section 30 and the tow mouthpiece section 40. The smoking machine was run through 12 puffs, one every 30 seconds, allowing the thermocouples to monitor the vapor temperature at the downstream end of the vapor cooling section from the 1st puff to the 12th puff.

[0200] Figure 3 The vapor temperature per puff is shown for the CA and CAP films and the PLA film.The bar graph shows that the CA and CAP films performed comparably to the PLA film, each cooling the vapor from the tobacco segment 20 to between 45°C and 60°C.

[0201] The invention has been described in detail with particular reference to specific embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

Claims

1. A steam generating article comprising a plurality of segments assembled in the form of a rod, wherein the section comprises a steam forming section and a steam cooling section located within the rod downstream of the steam forming section, wherein the steam cooling section comprises a curled cellulose ester (CE) film, and Wherein the CE membrane comprises cellulose acetate propionate.

2. The article of claim 1, wherein the CE film comprises up to 10 wt%, 0.1 wt% to 10 wt%, 1 wt% to 10 wt%, 5 wt% to 10 wt%, less than 0.5 wt%, less than 0.4 wt%, less than 0.3 wt%, less than 0.2 wt%, or less than 0.1 wt% of a plasticizer based on the total weight of the CE film.

3. The article of claim 1, wherein the CE film does not contain a plasticizer.

4. The article of any one of the preceding claims, wherein the CE film further comprises cellulose acetate.

5. The article of any one of the preceding claims, wherein the CE film comprises 5 to 65, 10 to 65, 15 to 65, 20 to 65, 5 to 60, 10 to 60, 15 to 60, 20 to 60, 5 to 55, 10 to 55, 15 to 55, 20 to 55, 5 to 50, 10 to 50, 15 to 50, 20 to 50, 5 to 45, 10 to 45, 15 to 45, 20 to 45, 5 to 40, 10 to 40, 15 to 40, 20 to 40, 5 to 35, 10 to 35, 15 to 35, 20 to 35, 5 to 30, 10 to 30, 15 to 30, 20 to 30, 5 to 25, 10 to 25, 15 to 25, 20 to 25, 5 to 20, 10 to 20 or 15 to 20 curls per inch (CPI).

6. The article of any one of the preceding claims, wherein the CE film comprises a curl having a height of 0.01 to 3 mm or 0.1 to 2 mm.

7. The article of any one of the preceding claims, wherein the CE film has a thickness of 10 to 150 μm, 10 to 125 μm, 10 to 100 μm, 10 to 75 μm, 10 to 70 μm, 10 to 60 μm, 10 to 50 μm, 10 to 40 μm, 10 to 30 μm, 10 to 20 μm, 20 to 150 μm, 20 to 125 μm, 20 to 100 μm, 20 to 75 μm, 20 to 70 μm, 20 to 60 μm, 20 to 50 μm, 20 to 40 μm, 20 to 30 μm, 30 to 150 μm, 30 to 125 μm, 30 to 100 μm, 30 to 75 μm, 100μm, 30 to 70μm, 30 to 60μm, 30 to 50μm, 30 to 40μm, 40 to 150μm, 40 to 125μm, 40 to 100μm, 40 to 75μm, 40 to 70μm, 40 to 60μm, 40 to 50μm, 50 to 150μm, 50 to 125μm, 50 to 100μm, 50 to 75μm, 50 to 70μm, 50 to 60μm, 60 to 150μm, 60 to 125μm, 60 to 100μm, 60 to 75μm, 60 to 70μm, 70 to 150μm, 70 to 125μm, 70 to 100μm or 70 to 75μm in thickness.

8. The article of any one of the preceding claims, wherein the steam cooled section has a porosity in the longitudinal direction of 30% to 96%, 50% to 80%, or 60% to 70%.

9. The article of any one of the preceding claims, wherein the steam cooling section has a length of 5 to 50 mm, 5 to 40 mm, 5 to 30 mm, or 7 to 28 mm.

10. The article of any preceding claim, wherein the steam cooling section is configured to cool steam emitted from the steam forming section by at least 50°C, at least 60°C, at least 70°C, at least 80°C, at least 90°C, or at least 100°C.

11. The article according to any of the preceding claims, further comprising (A) a filtering section located within the rod downstream of the steam cooling section, (B) a spacing section located within the rod between the steam forming section and the steam cooling section, or both (A) and (B).

12. The article of any one of the preceding claims, wherein the CE membrane comprises micropores, or wherein the CE membrane is free of micropores.

13. A method of forming a steam generating article, the method comprising: (a) combining cellulose ester (CE), a solvent, and optionally a plasticizer to form a casting solution; (b) casting the casting solution and evaporating the solvent to form a CE membrane; (c) curling the CE membrane to form a curled CE membrane; (d) gathering and wrapping the rolled CE film into a rod shape to form a steam cooling section; and (e) longitudinally aligning and wrapping the steam generating section with the steam cooling section to form a steam generating article, Wherein the CE comprises cellulose acetate propionate.

14. The method of claim 13, wherein step (a) further comprises combining cellulose acetate to form the casting solution.

15. A method of forming a steam generating article, the method comprising: (a) heating cellulose acetate propionate (CAP) and optionally a plasticizer in an extruder to form a melt; (b) extruding the melt through a die to form a CAP film; (c) curling the CAP film to form a curled CAP film; (d) gathering and wrapping the curled CAP film into a rod shape to form a steam cooling section; and (e) longitudinally aligning and wrapping the steam generating section with the steam cooling section to form a steam generating article.

16. A steam generating article comprising a plurality of segments assembled in the form of a rod, wherein the section comprises a steam forming section and a steam cooling section located within the rod downstream of the steam forming section, The steam cooling section comprises a perforated and curled cellulose ester (CE) film.

17. The article of claim 16, wherein the CE film comprises cellulose acetate, cellulose acetate propionate, or both.

18. The article of any one of claims 16 to 17, wherein the CE film comprises up to 10 wt%, 0.1 wt% to 10 wt%, 1 wt% to 10 wt%, 5 wt% to 10 wt%, less than 0.5 wt%, less than 0.4 wt%, less than 0.3 wt%, less than 0.2 wt%, or less than 0.1 wt% of plasticizer based on the total weight of the CE film.

19. The article of any one of claims 16 to 17, wherein the CE film does not contain a plasticizer.

20. The article of any one of claims 16 to 19, wherein the CE film comprises 5 to 65, 10 to 65, 15 to 65, 20 to 65, 5 to 60, 10 to 60, 15 to 60, 20 to 60, 5 to 55, 10 to 55, 15 to 55, 20 to 55, 5 to 50, 10 to 50, 15 to 50, 20 to 50, 5 to 45, 10 to 4 20 to 25, 5 to 20, 10 to 20, 15 to 20, or 15 to 20 curls per inch (CPI).

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