VAPOR-GENERATING ARTICLE CONTAINING CELLULOSE ESTER FILM

Abstract

A vapor-generating article comprises a plurality of segments assembled in the form of a rod. The segments include a vapor-forming segment and a vapor-cooling segment located downstream of the vapor-forming segment within the rod. The vapor-cooling segment comprises a crimped cellulose ester (CE) film. The crimped CE film may comprise cellulose acetate propionate, perforations, or both.

Claims

1. A vapor-generating article comprising a plurality of segments assembled in the form of a rod, wherein the segments comprise a vapor-forming segment and a vapor-cooling segment located downstream of the vapor-forming segment within the rod, wherein the vapor-cooling segment comprises a crimped cellulose ester (CE) film, and wherein the CE film comprises cellulose acetate propionate.

2. The article of claim 1, wherein the CE film comprises up to 10 wt %, 0.1 to 10 wt %, 1 to 10 wt %, 5 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 comprises no plasticizer.

4. The article of claim 1, wherein the CE film further comprises cellulose acetate.

5. The article of claim 1, 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 crimps per inch (CPI).

6. The article of claim 1, wherein the CE film comprises crimps having a height of 0.01 to 3 mm, or 0.1 to 2 mm.

7. The article of claim 1, wherein the CE film has a thickness of 10 to 150 m, 10 to 125 m, 10 to 100 m, 10 to 75 m, 10 to 70 m, 10 to 60 m, 10 to 50 m, 10 to 40 m, 10 to 30 m, 10 to 20 m, 20 to 150 m, 20 to 125 m, 20 to 100 m, 20 to 75 m, 20 to 70 m, 20 to 60 m, 20 to 50 m, 20 to 40 m, 20 to 30 m, 30 to 150 m, 30 to 125 m, 30 to 100 m, 30 to 75 m, 30 to 70 m, 30 to 60 m, 30 to 50 m, 30 to 40 m, 40 to 150 m, 40 to 125 m, 40 to 100 m, 40 to 75 m, 40 to 70 m, 40 to 60 m, 40 to 50 m, 50 to 150 m, 50 to 125 m, 50 to 100 m, 50 to 75 m, 50 to 70 m, 50 to 60 m, 60 to 150 m, 60 to 125 m, 60 to 100 m, 60 to 75 m, 60 to 70 m, 70 to 150 m, 70 to 125 m, 70 to 100 m, or 70 to 75 m.

8. The article of claim 1, wherein the vapor-cooling segment has a porosity of 30 to 96%, 50 to 80%, or 60 to 70% in the longitudinal direction.

9. The article of claim 1, wherein the vapor-cooling segment 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 claim 1, wherein the vapor-cooling segment is configured to cool a vapor evolved from the vapor-forming segment 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 of claim 1, which further comprises (A) a filter segment located downstream of the vapor-cooling segment within the rod, (B) a spacer segment located between the vapor-forming segment and the vapor-cooling segment within the rod, or both (A) and (B).

12. The article of claim 1, wherein the CE film comprises micropores, or wherein the CE film is free of micropores.

13. A method of forming a vapor-generating article, the method comprising: (a) combining a cellulose ester (CE), a solvent, and optionally, a plasticizer, to form a dope; (b) casting the dope and evaporating the solvent to form a CE film; (c) crimping the CE film to form a crimped CE film; (d) gathering and wrapping the crimped CE film into a rod-shape to form a vapor-cooling segment; and (e) aligning and wrapping a vapor-forming segment with the vapor-cooling segment longitudinally to form a vapor-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 dope.

15. A method of forming a vapor-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) crimping the CAP film to form a crimped CAP film; (d) gathering and wrapping the crimped CAP film into a rod-shape to form a vapor-cooling segment; and (e) aligning and wrapping a vapor-forming segment with the vapor-cooling segment longitudinally to form a vapor-generating article.

16. A vapor-generating article comprising a plurality of segments assembled in the form of a rod, wherein the segments comprise a vapor-forming segment and a vapor-cooling segment located downstream of the vapor-forming segment within the rod, wherein the vapor-cooling segment comprises a perforated and crimped 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 claim 16, wherein the CE film comprises up to 10 wt %, 0.1 to 10 wt %, 1 to 10 wt %, 5 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.

19. The article of claim 16, wherein the CE film comprises no plasticizer.

20. The article of claim 16, 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 crimps per inch (CPI).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 is a schematic cross-sectional diagram of an exemplary vapor-generating article according to the invention.

[0042] FIG. 2 is a schematic cross-sectional diagram of another exemplary vapor-generating article according to the invention.

[0043] FIG. 3 is a bar graph showing the vapor temperature immediately after the vapor-cooling segment containing various film materials over the course of 12 puffs.

DETAILED DESCRIPTION OF THE INVENTION

[0044] It has been surprisingly found that certain cellulose esters (CE) may be formed into films using only a small amount of plasticizer or without using a plasticizer at all, that such CEs can have sufficiently high melting points to withstand the conditions inside a HNB tobacco product during operation, that films made from such CEs can provide a suitable vapor temperature drop with minimum pressure drop and sufficient hardness for processing into vapor-cooling segments for HNB tobacco products.

Vapor-Generating Article

[0045] In one aspect, the invention includes a vapor-generating article comprising a plurality of segments assembled in the form of a rod. The segments comprise a vapor-forming segment and a vapor-cooling segment located downstream of the vapor-forming segment within the rod. The vapor-cooling segment comprises a crimped cellulose ester (CE) film.

[0046] The vapor-cooling segment is designed to cool the vapor generated from the vapor-forming segment.

[0047] As used herein, the term vapor includes aerosol.

[0048] The term rod denotes a generally cylindrical element having a substantially circular, oval, or elliptical radial cross-section.

[0049] The term crimp or variations thereof refer a plurality of folds or ridges. Preferably, when the vapor-generating article has been assembled, the folds or ridges extend in a longitudinal direction with respect to the rod.

[0050] The terms upstream and downstream may be used to describe relative positions of elements, segments, or components of the vapor-generating article. For simplicity, the terms upstream and downstream refer to a relative position along the rod of the vapor-generating article with reference to the direction in which the vapor is drawn through the rod.

[0051] The segments of the vapor-generating article can be assembled by a suitable wrapper, such as cigarette paper. The cigarette paper may be any suitable material for wrapping components of a vapor-generating article in the form of a rod. The cigarette paper should grip the segments of the vapor-generating article when the article is assembled and hold them in place within the rod.

[0052] The vapor-generating article may be substantially cylindrical in shape. The article may be substantially elongate. The article may have a length and a circumference substantially perpendicular to the length. Likewise, the vapor-forming segment may be substantially cylindrical in shape. The vapor-forming segment may be substantially elongate. The vapor-forming segment may also have a length and a circumference substantially perpendicular to the length. The vapor-forming segment may be received in the vapor-generating article such that the length of the vapor-forming segment is substantially parallel to the airflow direction in the vapor-generating article. Similarly, the vapor-cooling segment may be substantially cylindrical in shape. The vapor-cooling segment may be substantially elongate. The vapor-cooling segment may also have a length and a circumference substantially perpendicular to the length. The vapor-cooling segment may be received in the vapor-generating article such that the length of the vapor-cooling segment is substantially parallel to the airflow direction in the vapor-generating article.

[0053] The vapor-generating article may have any desired length and diameter. For example, the article may have a total length of 30 mm to 100 mm. The article may have an external diameter of 5 mm to 12 mm.

[0054] The vapor-generating article may also include a filter or mouthpiece. The filter may be located downstream of the vapor-cooling segment, e.g., at the downstream end of the vapor-generating article. The filter may be a cellulose acetate tow filter plug. The filter may be substantially cylindrical in shape. The filter may be substantially elongate. The filter may have a length and a circumference substantially perpendicular to the length. The filter may be received in the vapor-generating article such that the length of the filter is substantially parallel to the airflow direction in the vapor-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, e.g., 7 mm. The filter may have an external diameter of 5 mm to 12 mm.

[0055] The vapor-generating article may include a spacer segment located downstream of the vapor-forming segment, e.g., between the vapor-forming segment and the vapor-cooling segment within the rod. The spacer segment may serve one or more functions, such as (a) to position the vapor-forming segment towards the upstream end of the vapor-generating article so that it can be contacted with a heating unit, (b) to prevent the vapor-forming segment from being forced along the rod towards the vapor-cooling element when a heating unit is inserted into the vapor-forming segment, and (c) to provide a buffer zone between the vapor-forming segment and the vapor-cooling segment. The spacer segment may be a hollow tube made of cellulose acetate.

Vapor-Forming Segment

[0056] The vapor-forming segment may include a solid vapor-forming substrate. Alternatively, the vapor-forming segment may include both solid and liquid components. The vapor-forming substrate may include a tobacco material containing volatile tobacco flavor compounds, which are released from the substrate upon heating. Alternatively, the vapor-forming substrate may contain a non-tobacco material. The vapor-forming substrate may further comprise one or more vapor formers. Examples of vapor formers include glycerin and propylene glycol.

[0057] The solid vapor-forming substrate may be in the form of powder, granules, pellets, shreds, spaghettis, strips, and/or sheets containing herb leaf, tobacco leaf, fragments of tobacco ribs, reconstituted tobacco, homogenized tobacco, extruded tobacco, and/or expanded tobacco. The solid vapor-forming substrate may be in loose form or may be provided in a suitable container or cartridge. For example, the solid vapor-forming substrate may be contained within a paper or other wrapper and may have the form of a plug. Where the vapor-forming substrate is in the form of a plug, the entire plug including any wrapper may be considered the vapor-forming segment.

[0058] The solid vapor-forming substrate may include additional tobacco and/or non-tobacco volatile flavor compounds, which are released upon heating. The solid vapor-forming substrate may include capsules containing, for example, the additional tobacco and/or non-tobacco volatile flavor compounds. Such capsules may melt during heating of the substrate.

[0059] The solid vapor-forming substrate may be provided on or embedded in a thermally stable carrier. The carrier may be in the form of powder, granules, pellets, shreds, spaghettis, strips, and/or films. The solid vapor-forming substrate may be deposited on the surface of the carrier in the form of, for example, a film, foam, gel, and/or slurry. The solid vapor-forming substrate may be deposited on the entire surface of the carrier, or alternatively, may be deposited in a pattern to provide a non-uniform flavor delivery during use. The vapor-forming segment may have the shape of a rod.

[0060] The vapor-forming segment may have a substantially circular radial cross-section.

[0061] The vapor-forming segment may have a diameter of 5 mm to 10 mm.

Vapor-Cooling Segment

[0062] The main function of the vapor-cooling segment is to reduce the temperature of the vapor generated from the vapor-forming segment to a comfortable level for the user (e.g., 40 to 60 C.), without inducing too much pressure drop. The cooling may be achieved in several ways.

[0063] For example, the vapor-cooling segment may act as a heat-sink to cool the temperature of the vapor drawn through the segment by thermal transfer. Components of the vapor can interact with the vapor-cooling segment and loose thermal energy.

[0064] The vapor-cooling segment may also cool the temperature of the vapor drawn through the segment by undergoing a phase transformation, which absorbs heat energy from the vapor stream. For example, the material forming the vapor-cooling segment may undergo a phase transformation such as melting or a glass transition that requires the absorption of heat energy.

[0065] The vapor-cooling segment may also lower the perceived temperature of the vapor drawn through the segment by causing condensation of components, such as water vapor, from the vapor stream. Due to condensation, the vapor stream may be drier after passing through the vapor-cooling segment. Because of the lower moisture content, the user may perceive the temperature of this vapor to be lower than its actual temperature.

[0066] The vapor-cooling segment may be configured to cool a vapor evolved from the vapor-forming segment 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 may be controlled multiple ways, including by adjusting the thickness of and/or the number of crimps in the CE film in the vapor-cooling segment. Thinner films tend to be more flexible, which allows for a higher crimping frequency. Higher crimping frequencies tend provide greater surface area with which to cool the vapor, for a given film weight. Higher film weight can also yield better cooling.

[0067] In addition to cooling, the vapor-cooling segment may act as a filter to remove moisture, which contribute to the cooling effect, as well as undesirable phenolic compounds (e.g., phenols and cresols) from the vapor. The phenolic compounds may be adsorbed by the CE film as well as absorbed by water droplets condensed on the CE film.

[0068] The vapor-cooling segment may have a total surface area of 300 mm.sup.2 per mm of length to 1000 mm.sup.2 per mm of length.

[0069] The vapor-cooling segment preferably offers a low resistance to the passage of air through the rod. The vapor-cooling segment preferably does not substantially affect the resistance to draw of the vapor-generating article. Preferably, there is a low-pressure drop from an upstream end of the vapor-cooling segment to a downstream end of the vapor-cooling segment.

[0070] A low-pressure drop can be achieved through a higher porosity vapor-cooling segment. The porosity of the vapor-cooling segment can be increased by lowering the film weight, decreasing the film surface area, or both.

[0071] In one or more embodiments, the vapor-cooling segment may have a porosity in a longitudinal direction of 30 to 96%, 50 to 80%, or 60 to 70%. The longitudinal porosity may be defined by a ratio of the cross-sectional area of material forming the vapor-cooling segment and an internal cross-sectional area of the vapor-generating article at the portion containing the vapor-cooling segment.

[0072] The vapor-cooling segment may be formed from the crimped CE film by gathering and wrapping the film into a segment that defines a plurality of longitudinally extending channels. A radial cross-sectional profile of the vapor-cooling segment may show the channels as being randomly oriented.

[0073] The vapor-cooling segment may comprise an outer tube or wrapper that contains or locates the longitudinally extending channels. For example, the crimped CE film may be wrapped in a wrapper material (such as filter paper) to form the vapor-cooling segment.

[0074] The vapor-cooling segment may have the shape of a rod.

[0075] The vapor-cooling segment 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.

[0076] The vapor-cooling segment may have a substantially circular cross-section and a diameter of 5 mm to 10 mm.

[0077] The vapor-cooling segment may have a circumference in the range of 23 to 25 mm, 18 to 23 mm, or 16 to 18 mm.

[0078] The vapor-cooling segment should have a Filtrona hardness of at least 90%, or at least 95%, to survive in the combiner.

[0079] Preferably, the pressure drop from the vapor-cooling segment is less than 100 mmWG, less than 80 mmWG, or less than 40 mmWG.

[0080] In one or more embodiments, the temperature of the vapor entering the vapor-cooling segment may be up to 210 C. during a puff and up to 130 C. between puffs.

[0081] In one or more embodiments, the temperature of the vapor exiting the vapor-cooling segment may be in the range of 40 to 60 C., or below 50 C.

Cellulose Ester Film

[0082] The vapor-cooling segment comprises a crimped cellulose ester (CE) film.

[0083] The cellulose ester may be cellulose acetate (CA), cellulose acetate propionate (CAP), or mixtures of the two.

[0084] Both materials have sufficiently high melting temperatures (e.g., >180 C., or [0085] >200 C.) so that they are not susceptible to melting from the heat of the vapor during use. Film melting can cause the pores in the vapor-cooling segment to narrow or close, thereby negatively affecting the pressure drop and/or cooling efficiency of the vapor-cooling segment.

[0086] In one or more embodiments, the CE film comprises CA. The CE film may comprise from 50 to 100 wt %, 50 to 99 wt %, 50 to 98 wt %, 50 to 97 wt %, 50 to 96 wt %, 50 to 95 wt %, 50 to 94 wt %, 50 to 93 wt %, 50 to 92 wt %, 50 to 91 wt %, or 50 to 90 wt % of CA, based on the total weight of the CE film. The balance of the CE film may comprise CAP and/or one or more additives.

[0087] In one or more embodiments, the CE film comprises CAP. The CE film may comprise from 50 to 100 wt %, 50 to 99 wt %, 50 to 98 wt %, 50 to 97 wt %, 50 to 96 wt %, 50 to 95 wt %, 50 to 94 wt %, 50 to 93 wt %, 50 to 92 wt %, 50 to 91 wt %, or 50 to 90 wt % of CAP, based on the total weight of the CE film. The balance of the CE film may comprise CA and/or one or more additives.

[0088] CAP is a more flexible material than CA, so that a plasticizer is not required when the film comprises CAP, particularly in amounts 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.

[0089] Cellulose acetate, when used in connection with the vapor-cooling segment, refers to cellulose diacetate. The CA may have a degree of substitution (DS) (i.e., average number of substituents per anhydroglucose monomer unit) of 2 to 2.6.

[0090] The CAP may have a DS of acetate of 0.1 to 1, 0.1 to 0.5, or 0.1 to 0.3. The CAP may have a DS of propionate of 2 to 2.9, 2.1 to 2.8, or 2.3 to 2.7.

[0091] The CE can be produced by any method known in the art. Examples of processes for producing CEs are taught in Kirk-Othmer, Encyclopedia of Chemical Technology, 5th Edition, Vol. 5, Wiley-Interscience, New York (2004), pp. 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, among others.

[0092] One method of producing CEs involves esterifying the cellulose by mixing it with one or more acetylating agents and an acidic catalyst. The cellulose is then converted to a cellulose triester. After esterifying the cellulose to the triester, part of the acyl substitutents may be removed by hydrolysis or by alcoholysis to give a secondary cellulose ester, which can 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 can then be washed with water to remove reaction by-products followed by dewatering and drying.

[0093] The term cellulose triester includes cellulose esters that are not completely substituted with acyl groups. For example, the cellulose triester can have a DS of 2.85 to 2.95.

[0094] Depending on the method employed, the distribution of the acyl substituents can be random or non-random. Secondary cellulose esters can also be prepared directly with no hydrolysis/alcoholysis by using a limiting amount of the acetylating agent. This latter process is particularly useful when the reaction is conducted in a solvent that will dissolve cellulose.

[0095] The acetylating agent can be carboxylic acids, acid anhydrides, and/or carboxylic acid halides (particularly, carboxylic acid chlorides). The carboxylic acids can be acetic acid, propionic acid, or mixtures thereof. The acid anhydrides can be acetic anhydride, propionic anhydride, or mixtures thereof. The acid chlorides can be acetyl chloride, propionyl chloride, or mixtures thereof.

[0096] Acidic catalysts useful for promoting the esterification of cellulose typically include sulfuric acid or a mixture of sulfuric acid and at least one other acid. Other acidic catalysts not containing sulfuric acid can similarly be used to promote the esterification reaction. In the case of sulfuric acid, at least some of the hydroxyl groups in the cellulose can become initially functionalized as sulfate esters during the esterification reaction. As discussed above, once exhaustively esterified, the cellulose can then be subjected to a controlled partial de-esterification step.

[0097] The cellulose ester may have a number average molecular weight ranging from 30,000 amu to 100,000 amu, or from 50,000 amu to 80,000 amu. All molecular weight recited herein, unless otherwise specified, are number average molecular weights. The CE may be provided in pellet, granule, powder, or flake form.

[0098] Blends of different molecular weight cellulose esters may be used. For example, a blend of a high molecular weight CE, e.g., a CE having a molecular weight above 60,000 amu, may be blended with a low molecular weight CE, e.g., a CE having a molecular weight below 60,000 amu. The weight ratio of high molecular weight CE to low molecular weight CE may vary, such as from 1:10 to 10:1, from 1:5 to 5:1, or from 1:3 to 3:1.

[0099] The CE may have a polydispersity index from 2 to 4, from 1.5 to 2.5, from 1.75 to 2.25, or from 1.8 to 2.2.

[0100] The cellulose ester described herein may be formed into a film and used in the vapor-cooling segment.

[0101] In addition to cellulose ester, the CE film may include one or more additives, such as plasticizers, processing aids, and/or release agents.

[0102] Plasticizers are compounds that reduce the glass transition temperature, melt viscosity, and/or elastic modulus of the CE, making the plasticized CE more susceptible to melt processing.

[0103] A wide variety of plasticizers are known for plasticizing CE. If used, preference should be given to food-grade plasticizers, since some plasticizers may be prohibited in inhalation products in some jurisdictions. For example, phthalates, phosphorus, and chlorinated plasticizers may be prohibited.

[0104] As used herein, the term food-grade refers to a material that has been approved for contact (directly or indirectly) with food. Such materials may be classified as such if they conform to the requirements of the United States Pharmacopeia (USP-grade), the National Formulary (NF-grade), and/or the Food Chemicals Codex (FCC-grade) as of Apr. 30, 2017.

[0105] Examples of food-grade plasticizers include triacetin, diacetin, tripropionin, trimethyl citrate, triethyl citrate, tributyl citrate, eugenol, cinnamyl alcohol, alkyl lactones (e.g., -valerolactone), methoxy hydroxy acetophenone (acetovanillone), vanillin, ethylvanillin, polyethylene glycols, 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.

[0106] If used, the amount of plasticizer may be chosen to (i) reduce the glass transition temperature of the CE (e.g., too low a plasticizer content may not reduce the glass transition temperature enough to allow for melt processing) and (ii) maintain desirable mechanical properties of the CE (e.g., too high a plasticizer content may reduce the tensile strength of the final composition).

[0107] In various embodiments, the CE film may comprise up to 10 wt %, from 0.1 to 10 wt %, from 1 to 10 wt %, from 5 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.

[0108] In one or more embodiments, the CE film comprises no plasticizer.

[0109] The CE film may include a processing aid. If included, the processing aid may be present in an amount from 0.05 to 10 wt %, from 0.1 to 5 wt %, or from 0.5 to 2.5 wt %, based on the total weight of the CE film. Examples of processing aids include titanium dioxide, aluminum oxide, zirconium oxide, silica (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 an average particle size by volume from 0.01 to 50 m, from 0.02 to 40 m, or from 0.05 to 30 m. The particle size may be determined, for example, by sieve analysis.

[0110] One or more release agents may be included to improve releasability of the CE film, once formed, from a backing sheet or substrate. If included, the release agent may be present from 0.01 to 10 wt %, from 0.05 to 5 wt %, from 0.05 to 1 wt. %, or from 0.05 to 0.5 wt. %, based on the total weight of the CE film. The release agent is typically included when the film is solvent cast, and is added to the dope. Typical release agents include fatty acids, such as stearic acid.

[0111] The CE film is crimped to increase surface area to improve heat absorption as compared to a film with less surface area.

[0112] The CE film may comprise crimps in the 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 crimps per inch (CPI).

[0113] The crimps may have a height of 0.01 to 3 mm, or 0.1 to 2 mm. As used herein, crimp height refers to the distance between the peak and the valley of a crimp.

[0114] The CE film may have a thickness in the range of 10 to 150 m, 10 to 125 m, 10 to 100 m, 10 to 75 m, 10 to 70 m, 10 to 60 m, 10 to 50 m, 10 to 40 m, 10 to 30 m, 10 to 20 m, 20 to 150 m, 20 to 125 m, 20 to 100 m, 20 to 75 m, 20 to 70 m, 20 to 60 m, 20 to 50 m, 20 to 40 m, 20 to 30 m, 30 to 150 m, 30 to 125 m, 30 to 100 m, 30 to 75 m, 30 to 70 m, 30 to 60 m, 30 to 50 m, 30 to 40 m, 40 to 150 m, 40 to 125 m, 40 to 100 m, 40 to 75 m, 40 to 70 m, 40 to 60 m, 40 to 50 m, 50 to 150 m, 50 to 125 m, 50 to 100 m, 50 to 75 m, 50 to 70 m, 50 to 60 m, 60 to 150 m, 60 to 125 m, 60 to 100 m, 60 to 75 m, 60 to 70 m, 70 to 150 m, 70 to 125 m, 70 to 100 m, or 70 to 75 m.

[0115] The crimped CE film in the vapor-cooling segment may have a total surface area in the range of 30 to 480 cm.sup.2, or 72 to 330 cm.sup.2.

Film Porosity

[0116] In one or more embodiments, in addition to crimping, the CE film may be porous. The pores may be micro (pore diameter<2 nm), meso (pore diameter 2 to 50 nm), and/or macro (pore diameter>50 nm). Porous CE films tend to appear visually white or opaque to the naked eye and are lighter in weight than non-porous CE films.

[0117] The pores may be produced chemically by solvent casting the CE from a dope 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.

[0118] In one or more embodiments, the crimped CE film comprises micropores.

[0119] In one or more other embodiments, the crimped CE film is free of pores.

[0120] In one or more other embodiments, the crimped CE film is free of micropores.

[0121] CE films with little or no pores tend to be visually clear to the naked eye and are denser than porous CE films.

Film Perforations

[0122] In one or more embodiments, in addition to crimping, the CE film may have perforations. In contrast to pores, perforations refer to openings or holes in the CE film that are mechanically formed, such as by punching, cutting, piercing, etc.

[0123] The perforations may have a diameter of 0.1 to 10 mm. Perforation diameter refers to the longest straight-line distance between any two points on the perimeter of the opening or hole in the CE film.

[0124] The CE film may have anywhere from 1 to 100 perforations per square centimeter (p/cm.sup.2), or 4 to 80 p/cm.sup.2.

[0125] The perforations in the CE film can have symmetrical shapes, asymmetrical shapes, or both. Examples of symmetrical shapes include circles, semi-circles, heart-shapes, ovals, certain triangles (e.g., equilateral, isosceles), 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, obtuse, acute), trapezoids, parallelograms, etc.

[0126] In one or more embodiments, the crimped and perforated CE film may be free of chads. Chads refer to fragments of the CE film that are created when perforations are made in the film. In the case of a chad-free film, the chads are fully detached from the CE film.

[0127] In one or more other embodiments, the crimped and perforated CE film may comprise partially attached chads. Partially attached chads mean that a part of the chads is still attached or connected to the film. The partially attached chads may impart one or more advantages to the CE film, including providing increased surface area for cooling the vapor, more consistent flow, less pressure drop, and/or creating turbulent flow through the vapor-cooling segment.

[0128] The partially attached chads may have a shape resembling a letter in the English alphabet, such as C, V, or U.

[0129] When raised above or lowered below the plane of the CE film, the partially attached chads may be aligned perpendicular, parallel, or at an angle relative to the direction of the vapor flow through the vapor-cooling segment.

[0130] The CE film may be prepared by solvent casting or melt extrusion.

Solvent Casting

[0131] Processes for preparing CE films by solvent casting are known. In general, the solvent casting process comprises combining CE and optionally, a plasticizer, a processing aid, and/or a release agent in a solvent to form a mixture called a dope. Examples of suitable solvents include acetone, methylene chloride, ethyl lactate, methyl ethyl ketone, and dichloromethane.

[0132] Solvent casting may be used to prepare CE films comprising CA, CAP, or both. The dope may or may not include a plasticizer.

[0133] Typically, CA is added to the solvent in the form of flakes or powders, while CAP is added in the form of pellets. The dope is mixed until the CE is dissolved.

[0134] The dope may then be cast onto a casting band and dried to evaporate the solvent and obtain a film. Adding a release agent to the dope can facilitate removing the film from the casting band. The film may be further dried and then crimped using a crimper.

[0135] One example of a crimper is a stuffing box or stuffer box crimper where a plurality of rollers are used to generate friction, which causes the film to buckle and form crimps. Other types of crimpers may also be used.

[0136] In the case of a porous CE film, after removing the film from the casting band, the film may be quenched in a non-solvent (e.g., water), dried, and then crimped.

[0137] In the case of a perforated CE film, after the film is dried, it may be perforated, for example, by contacting the film with one or more punch rollers, which impart holes or openings in the film. The punch roller(s) may generate completely detached chads or, more preferably, partially detached chads. The perforated film may then be passed to a crimper to undergo crimping.

[0138] If desired, the chads may be removed from the film in case they are completely detached or raised from the plane of the film in case they are partially detached (a) during the perforating step, (b) after the perforating step but before crimping, and/or (c) during the crimping step. Between the perforating and crimping steps, the perforated film may be passed over one or more additional rollers and/or through a stream of gas to remove or raise the chads. Alternatively or additionally, the chads may be removed or lifted from the film plane by action of the crimper.

Melt Extrusion

[0139] The CE and optionally, a plasticizer and/or any other additives, such as a processing aid, may be combined in a mixer or directly in an extruder. The CE may be in flake, powder, or pellet form.

[0140] The mixture is then heated in the extruder to form a melt. The melt is then extruded through a die (e.g., a flat-sheet die) to form a CE film. Optionally, the film may be wound through nips of a chill-roll stack for thickness sizing and cooling. Once cooled, the film may be crimped in a crimper or perforated and then crimped, as described above.

[0141] The melt extrusion may be performed at any suitable temperature, such as from 165 to 240 C., from 200 to 230 C., from 210 to 230 C., or from 220 to 230 C.

[0142] The extruder may be any suitable type, such as one equipped with a single screw or twin co-rotating screws.

[0143] An advantage of the present invention is that when the CE comprises CAP, a plasticizer is not required for the CE to be melt extruded. This is not the case when the CE is cellulose acetate alone.

FIGS. 1-2

[0144] FIG. 1 shows a representative vapor-generating article according to the invention.

[0145] FIG. 1 depicts a heat-not-burn (HNT) tobacco unit 10 which comprises a tobacco segment 20, a cooling filter segment 30, and a cellulose acetate tow segment 40. These three elements are wrapped separately by papers 21, 31, 41 and then assembled coaxially into a rod 11 by a wrapping paper 50 with heating end 12 and mouth end 13.

[0146] The tobacco segment 20 may contain tobacco substances in the form of leaves, paper, or powder. During use, those substances are heated at least above 140 C. to release nicotine. More nicotine and other constituents may be released with increasing heating temperature, e.g., up to 240 C. or up to 300 C.

[0147] After heating, as the user draws a puff from the mouth end 13, vapor generated in the tobacco segment 20 is cooled down and filtered as it passes through the cooling filter segment 30 and the cellulose acetate tow segment 40, and eventually inhaled by the user.

[0148] The cellulose acetate tow segment 40, as a mouthpiece, gives a finish appearance to the HNB tobacco unit 10. It can further filter the vapor coming through the cooling filter segment 30, which is generated from the tobacco segment 20. In addition, this cellulose acetate tow mouthpiece 40 can also prevent the CE film or larger substances from the tobacco segment 20 from being drawn into the user's mouth.

[0149] FIG. 2 shows another representative vapor-generating article according to the invention.

[0150] The article shown in FIG. 2 is similar to that of FIG. 1, except that it further includes a spacer segment 60 (e.g., a cellulose acetate hollow tube) between the tobacco segment 20 and the cooling filter segment 30, and a paper wrap 61.

General Provisions

[0151] To remove any doubt, the present invention includes and expressly contemplates and discloses any and all combinations of embodiments, features, characteristics, parameters, and/or ranges mentioned herein. That is, the subject matter of the present invention may be defined by any combination of embodiments, features, characteristics, parameters, and/or ranges mentioned herein.

[0152] It is contemplated that any ingredient, component, or step that is not specifically named or identified as part of the present invention may be explicitly excluded.

[0153] Any process/method, apparatus, article, compound, composition, embodiment, or component of the present invention may be modified by the transitional terms comprising, consisting essentially of, or consisting of, or variations of those terms.

[0154] As used herein, the indefinite articles a and an mean one or more, unless the context clearly suggests otherwise. Similarly, the singular form of nouns includes their plural form, and vice versa, unless the context clearly suggests otherwise.

[0155] The conjunction and/or means any, some, or all of the stated possibilities.

[0156] While attempts have been made to be precise, the numerical values and ranges described herein may be considered approximations. These values and ranges may vary from their stated numbers depending upon the desired properties sought to be obtained by the present disclosure as well as the variations resulting from the standard deviation found in the measuring techniques. Moreover, the ranges described herein are intended and specifically contemplated to include all sub-ranges and values within the stated ranges. For example, a range of 50 to 100 is intended to include all values within the range including sub-ranges such as 60 to 90, 70 to 80, etc.

[0157] Any two numbers of the same property or parameter reported in the working examples may define a range. Those numbers may be rounded off to the nearest thousandth, hundredth, tenth, whole number, ten, hundred, or thousand to define the range.

[0158] The content of all documents cited herein, including patents as well as non-patent literature, is hereby incorporated by reference in their entirety. To the extent that any incorporated subject matter contradicts with any disclosure herein, the disclosure herein shall take precedence over the incorporated content.

[0159] This invention can be further illustrated by the following working examples, although these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention.

EXAMPLES

Examples 1-5

[0160] Vapor-cooling segment samples were prepared using cellulose ester films (crimped CA and CAP films) with different thicknesses and loadings. Both the CA and CAP films, without plasticizer, were made by solvent casting. The films were then hand-crimped and then gathered into a rod-shape before being placed into a pre-wrapped paper sheath. The segment length of each sample was 27 mm.

[0161] The CA films were made from Eastman cellulose acetate CA-394-60S (T.sub.m=240-260 C.; MW.sub.n=60,000) or CA-398-30 (T.sub.m=230-250 C.; MW.sub.n=50,000) at different thicknesses.

[0162] The CAP film was made from Eastman TREVA GC6021 (T.sub.m=188-210 C.).

[0163] The cooling segment samples had the same inner diameter, length, and wrapping paper parameters. The wrapping papers were all 0.18-mm thick.

[0164] Table 1 below lists the physical parameters of the films used.

TABLE-US-00001 TABLE 1 Some parameters of CA and CAP films for 27-mm cooling segments. Film Film Film Film Example Thickness Length Width Surface Area No. Film Mat'l (m) (cm) (mm) (cm.sup.2) 1 CA-394-60S 25 45 27 243 2 CA-394-60S 60 20 27 108 3 CA-398-30 25 45 27 243 4 CA-398-30 70 18 27 97.2 5 TREVA 50 22 27 119

[0165] The vapor-cooling segment samples were tested for pressure drop using Pressure Drop and Ventilation Tester (CES 508) from Custom Electronics Systems, Inc. (Rural Hall, NC) and for Filtrona hardness. Table 2 shows the physical parameters of the samples as well as the results of the tests.

TABLE-US-00002 TABLE 2 Some parameters of 27-mm cooling segments formed by CA and CAP crimped films. Outer Pressure Filtrona Film Wrap Example Diameter Length Drop Hardness Porosity Weight Weight No. (mm) (mm) (mmWG) (%) (%) (mg) (mg) 1 7 27 9.3 95.9 69.2 386 79 2 7 27 6.4 97.5 67.1 406 80 3 7 27 19.7 96.7 69.2 454 78 4 7 27 3.3 98.6 65.5 439 79 5 7 27 5.2 97.3 69.9 441 80

[0166] As seen in Table 2, the segments using the thinner CA films (Exs. 1 and 3) needed a longer film loading (45 cm) to maintain the segment's hardness. Because a longer film was used, those films had a larger surface area, but also a higher pressure drop. Although a larger film surface area would help to reduce the temperature of the vapor, it can compromise the pressure drop.

Examples 6-9 and Reference

[0167] Vapor-cooling segment samples were prepared using cellulose ester films (crimped CA and CAP films) having the same thickness. Both the CA and CAP films, without plasticizer, were made by solvent casting. The films were then hand-crimped and then gathered into a rod-shape before being placed into a pre-wrapped paper sheath. The segment length was 18 mm.

[0168] The CA films were made from Eastman cellulose acetate CA-394-60S and CA-398-30.

[0169] The CAP films were made from Eastman TREVA GC6021 and CAP-482-20 (T.sub.m=188-210 C.).

[0170] The cooling segment samples had the same inner diameter, length, and wrapping paper parameters. The wrapping papers were all 0.18-mm thick.

[0171] The Reference example contained polylactic acid (PLA) crimped film, the material used in the vapor-cooling segment of the HeatStick heated tobacco unit offered by Philip Morris.

[0172] Table 3 below lists the physical parameters of the films used.

TABLE-US-00003 TABLE 3 Some parameters of films for 18-mm cooling segments. Film Film Film Film Example Thickness Length Width Surface Area No. Film Mat'l (m) (cm) (mm) (cm.sup.2) 6 CA-394-60S 30 42 18 151.2 7 CA-398-30 30 42 18 151.2 8 CAP-482-20 30 40 18 144 9 TREVA 30 40 18 144 Reference PLA 40 23 18 82.8

[0173] The vapor-cooling segment samples were tested for pressure drop using Pressure Drop and Ventilation Tester (CES 508) from Custom Electronics Systems, Inc. (Rural Hall, NC) and for Filtrona hardness. Table 4 shows the physical parameters of the samples as well as the results of the tests.

TABLE-US-00004 TABLE 4 Some parameters of 18-mm cooling segments formed by crimped films. Outer Pressure Filtrona Film Wrap Example Diameter Length Drop Hardness Porosity Weight Weight No. (mm) (mm) (mmWG) (%) (%) (mg) (mg) 6 7 18 12.5 96.8 62 300 54 7 7 18 21.8 95.5 62 373 54 8 7 18 12.6 97.8 63.8 332 53 9 7 18 13.8 96.6 63.8 316 53 Reference 7 18 6.6 94.6 72.3 240 n/a

[0174] The vapor-cooling segments of Examples 6-9 were assembled into full vapor-generating articles (or heat sticks) having the structure of FIG. 2. The articles included a 9-mm long cellulose acetate hollow tube 60 as the spacer segment.

[0175] The Reference example in this study was the commercialized HeatStick made with polylactic acid (PLA) crimped film as the vapor-cooling segment.

[0176] To compare the cooling effects of the CA and CAP films with the PLA film, all the full heat sticks were tested on the Borgwaldt LX20 linear smoking machine with a thermal couple measuring the vapor temperature between the vapor-cooling segment 30 and the tow mouthpiece segment 40. The smoking machine took 12 puffs, one every 30 seconds, allowing the thermal couple to monitor the vapor temperature at the downstream end of the vapor-cooling segment from the 1.sup.st puff to the 12.sup.th puff.

[0177] FIG. 3 shows the vapor temperature of each puff for the CA and CAP films as well as 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 down to between 45 C. and 60 C.

[0178] 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 made within the spirit and scope of the invention.