Non-flammable wrapper for non-combustible heat sticks

Abstract

According to the present disclosure, there is provided a paper suitable for use as a wrapper for a non-combustion heatable stick, the paper comprising a substrate web made from cellulose fibers combined with a flame-retardant filler, or alternatively, a coating formed from a low-flame-spread composition.

Description

[Technical Field]

[0001] (Related Applications) This application claims priority to U.S. Provisional Patent Application No. 63 / 006,576, filed April 7, 2020, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] Smoking articles, such as cigarettes, are traditionally made by wrapping a column of tobacco in cigarette paper. Smoking articles typically include a filter at one end for smoking the smoking article. The filter is attached to the smoking article using tipping paper that is glued to the white cigarette paper. The cigarette paper and tipping paper used to construct smoking articles are generally made from flax or other cellulose fibers and may contain one or more fillers, such as calcium carbonate.

[0003] When a smoking article is smoked, mainstream smoke is produced and inhaled through a filter. Mainstream smoke can contain various components that impart a particular flavor to the smoking article, which is detected not only by taste but also by the sense of smell. In addition to mainstream smoke, conventional smoking articles also produce sidestream smoke. Inhaling smoke exhaled by a smoker or sidestream smoke is commonly referred to as passive smoking.

[0004] In recent years, those skilled in the art have been producing non-combustion heated tobacco products that generate aerosol and provide users with a similar experience to traditional cigarettes without secondhand smoke. These types of smokeless products are commonly referred to as non-combustion heated tobacco sticks. By placing a non-combustion heated tobacco stick in an aerosol-generating device and heating it at a low temperature, an inhalable aerosol can be generated without burning the stick. For example, a non-combustion heated tobacco stick includes tobacco that can generate aerosol by heating it without burning it. Similar to conventional smoking articles, a non-combustion heated tobacco stick includes a column of aerosol-generating material wrapped in a wrapper. The aerosol-generating material can be produced in various forms, such as cut strands from various sheets similar to cigarettes, cut strands from gathered sheet material, or cut strands from a single sheet. The non-combustion heated tobacco stick is placed in a heating device that heats the stick to a low temperature, for example, about 200 to 450°C. The heating device generates heat, for example, by burning fuel using an electric element or by a chemical reaction.

[0005] In contrast to conventional smoking articles, non-combustion heating sticks should be non-combustible. In particular, non-combustion heating sticks should be unable to maintain a lit tip when exposed to an open flame or a high-temperature heating element. For example, ideally, non-combustion heating sticks should not be able to be lit and smoked like conventional cigarettes. In addition, non-combustion heating sticks preferably do not produce a large amount of combustion products when placed in a heating device. Furthermore, various government regulations currently require that non-combustion heating sticks cannot be used as conventional cigarettes.

[0006] To solve the above problems, wrappers for non-combustible heat-and-release sticks have traditionally been manufactured by laminating aluminum to a paper substrate. While aluminum is non-flammable, it can interfere with the stick's ability to produce a uniform aerosol from start to finish. In addition, aluminum increases the cost of the product. Also, aluminum is not biodegradable.

[0007] In view of the above problems, there is a need for improved wrappers for non-combustion heatable sticks, and in particular for improved wrappers that can render non-combustion heatable sticks non-combustible. Summary of the Invention [Means for solving the problem]

[0008] Generally, the present disclosure relates to a wrapper used to construct a non-combustion heat-and-release stick. In one aspect, the wrapper of the present disclosure is non-combustible when wrapped around a column of tobacco and placed in a conventional smoking machine and ignited. The wrapper of the present disclosure can be made primarily from biodegradable materials, making it environmentally friendly. In addition, the wrapper of the present disclosure can be configured so as not to adversely affect the aerosol-generating properties of the aerosol-generating material contained in the non-combustion heat-and-release stick.

[0009] Various techniques can be used alone or in combination with each other to manufacture wrappers for non-combustion heatable sticks that render the non-combustion heatable sticks non-flammable. For example, wrappers containing one or more flame-retardant fillers can be manufactured in accordance with the present disclosure. In another aspect, a low-flame-spread composition can be applied to one or both sides of the wrapper. In yet another aspect, a flame-retardant filler can be used in conjunction with a coating made from a low-flame-spread composition. Wrappers of the present disclosure can be made from a single layer of paper or substrate web, or can be made from multiple layers. In one embodiment, a wrapper of the present disclosure includes an outer wrapper and an inner wrapper, and one or more of the above-described techniques are incorporated into the outer wrapper, the inner wrapper, or both.

[0010] In one aspect, the present disclosure relates to a wrapper for a non-combustion heat-sensitive stick food product. The wrapper of the present disclosure includes a substrate web composed of a mixture of cellulose fibers and a flame-retardant filler. The substrate web has a first surface and an opposite second surface. The flame-retardant filler can include calcium silicate particles. For example, the calcium silicate particles are present in the substrate web in an amount greater than about 10% by weight, e.g., greater than about 16% by weight, and generally less than about 40% by weight, e.g., less than about 30% by weight, or less than about 24% by weight.

[0011] Alternatively, the flame-retardant filler contained in the substrate web can include clay particles, silicate particles, or metal hydroxide particles. For example, the flame-retardant filler can include kaolin particles, aluminum hydroxide particles, or a combination thereof. Each filler or each mixture of fillers is contained in the substrate web in an amount greater than about 10% by weight, e.g., greater than about 16% by weight, and generally in an amount less than about 40% by weight, e.g., less than about 30% by weight, or less than about 24% by weight.

[0012] The wrapper further includes a coating formed on the first surface of the substrate web. The coating includes a low-flame-spreading composition. For example, the coating can include a low-flame-spreading material alone or in combination with a viscosity modifier, a spacer, and / or filler particles. The low-flame-spreading material can include, for example, microcrystalline cellulose, alginate, starch, or any combination thereof. The microcrystalline cellulose can be ground microcrystalline cellulose, powdered microcrystalline cellulose, or colloidal microcrystalline cellulose. In one embodiment, the microcrystalline cellulose is depolymerized. The viscosity modifier or spacer can include a cellulose derivative, such as carboxymethyl cellulose, guar gum, or any other suitable natural or synthetic polymer.

[0013] As described above, the substrate web includes a flame-retardant filler composed of calcium silicate particles. In one embodiment, the calcium silicate particles are not coated, meaning that they are not covered with a different material. Generally, the calcium silicate particles can have an average particle size of about 0.1 to 30 μm, e.g., about 2 to 15 μm. As used herein, the particle size of the flame-retardant filler can be measured by light scattering or laser diffraction. Such a particle size analyzer is commercially available from Horiba Scientific as the LA-960 particle size analyzer. The substrate web may be configured to contain only the flame-retardant filler or to contain the flame-retardant filler in combination with other fillers.

[0014] The substrate web can have a basis weight of about 12 to 80 gsm. The substrate web can have an inherent air permeability of about 0 to 50 CU, for example, about 0 to 20 CU. As used herein, "inherent" air permeability refers to the air permeability of the substrate web before any coating or surface treatment (e.g., perforation, etc.) is applied.

[0015] The coating of the low-flame-spreading composition may be a continuous coating or a discontinuous coating. As used herein, a continuous coating is one that is continuous in the area formed on the substrate web. A discontinuous coating is one that is not continuous in the area formed on the substrate web. For example, a plurality of spaced-apart circumferential bands formed by the coating composition is a discontinuous coating.

[0016] When the coating is a continuous coating, the coating can generally cover more than about 40%, e.g., more than about 65%, more than about 80%, more than about 85%, more than about 90%, or more than about 95% of the surface area of ​​the first side of the substrate web. The coating can have a basis weight of about 0.5 to 10 gsm in the coated area.

[0017] The wrapper of the present disclosure may be a single layer or may include multiple layers. For example, the wrapper of the present disclosure may include two layers. When the wrapper of the present disclosure includes multiple layers, the substrate web of the present disclosure constitutes one of the multiple layers. In one embodiment, for example, the substrate web may constitute the inner layer of a two-layer wrapper or the outer layer of a two-layer wrapper.

[0018] In another aspect, the presently disclosed wrapper for a non-combustion heatable stick comprises an outer wrapper including cellulose fibers and an inner wrapper including a substrate web. The substrate web can be composed of a mixture of cellulose fibers and a flame-retardant filler. The flame-retardant filler can be, for example, silicate particles such as calcium silicate particles, clay particles such as kaolin particles, or metal hydroxide particles such as aluminum hydroxide particles. The flame-retardant filler can be present in the substrate web in an amount of about 10 to 45%, for example, about 27 to 38%. The substrate web can have a basis weight of about 20 to 50 gsm. In this embodiment, the substrate web can be uncoated. This means that the substrate web is not treated with a flame-reducing composition, yet still provides a wrapper with the desired flame-retardant properties.

[0019] In yet another aspect, the present disclosure relates to a wrapper for a non-combustion heat-sensitive stick, comprising a substrate web containing cellulose fibers. The substrate web has a first surface and an opposite second surface. The substrate web can include a coating formed on the first surface of the substrate web. The coating includes a low-flame-spreading composition. The coating can be formed continuously, in which case the coating can cover more than about 65%, for example, more than about 80%, of the surface area of ​​the first surface of the substrate web. When coated with the low-flame-spreading composition, the substrate web can have an air permeability of less than about 10 CU, for example, less than about 5 CU or less than about 2 CU, and a diffusivity of less than about 0.04 cm / s, for example, less than about 0.03 cm / s or less than about 0.02 cm / s. In this embodiment, the substrate web can optionally include filler particles. When contained in the substrate web, the filler particles include calcium carbonate particles or magnesium oxide particles. Alternatively, the substrate web can be free of filler particles. In this embodiment, the wrapper may be of a single layer design or of a two layer design, where the wrapper is of a two layer design, the substrate web may constitute the inner layer of the two layer design.

[0020] The present disclosure also relates to a non-combustion heatable stick. The non-combustion heatable stick of the present disclosure includes a column of aerosol-generating material and a wrapper encasing the column of aerosol-generating material, and the wrapper may be any of the wrappers described above. The aerosol-generating material may be made from any suitable plant. For example, in one embodiment, the aerosol-generating material is tobacco, such as cut tobacco, cast leaf tobacco, or reconstituted tobacco produced by a papermaking process. The wrapper of the present disclosure may be incorporated into the non-combustion heatable stick so that the non-combustion heatable stick exhibits non-combustibility when tested according to a predetermined combustion test. For example, when tested according to the combustion test, the non-combustion heatable stick of the present disclosure may extinguish in less than about 3 minutes, e.g., less than about 2.5 minutes, less than about 2 minutes, or less than about 1.5 minutes.

[0021] Other features and aspects of the present disclosure are described in detail below. [Brief explanation of the drawings]

[0022] A full and enabling disclosure of the present disclosure, directed to one skilled in the art, is set forth more particularly in the remainder of the specification, which makes reference to the accompanying drawings, in which:

[0023] [Figure 1] FIG. 1 is a plan view of one embodiment of a non-combustion heating device loaded with a non-combustion heating stick according to the present disclosure. [Figure 2] FIG. 2 is a plan view of another embodiment of a non-combustion heating device loaded with a non-combustion heating stick. [Figure 3] FIG. 3 is a plan view of yet another embodiment of a non-combustion heating device loaded with a non-combustion heating stick. [Figure 4] FIG. 4 shows some of the results obtained in the examples. [Figure 5] FIG. 5 shows some of the results obtained in the examples.

[0024] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] Those skilled in the art will appreciate that this disclosure is for purposes of describing exemplary embodiments only, and is not intended to limit the broader aspects of the disclosure.

[0026] Generally, the present disclosure is directed to paper products having low flammability. For example, the paper products of the present disclosure are well suited for use as non-flammable wrappers in the manufacture of non-combustible heat sticks.

[0027] Low-flammability properties can be incorporated into paper products of the present disclosure using a variety of techniques. Each technique can be used alone or in combination with other techniques to optimize a particular product for a desired application. In one aspect, for example, paper products of the present disclosure can be produced by incorporating a flame-retardant filler, such as silicate particles, into the paper. In another embodiment, paper products of the present disclosure can include cellulose fibers, alone or in combination with a filler. Paper products of the present disclosure can also be coated on one or both sides with a low-flame-spread composition (a low-flame-spread coating). The low-flame-spread composition can include a low-flame-spread material, such as a film-forming polymer or cellulose, a particulate or fibrous cellulose material, or a combination thereof. The low-flame-spread coating can be used alone or in combination with a flame-retardant filler. When incorporated into wrappers for non-combustion heatable sticks, paper products produced according to the present disclosure can be used in a single-layer design. Alternatively, a paper product made in accordance with the present disclosure may include two layers forming the outer or inner layer of the wrapper.

[0028] Of particular advantage, the paper products of the present disclosure can be made primarily from biodegradable materials, thereby providing the desired non-flammability for non-combustion heating applications and making the wrapper environmentally friendly.

[0029] Referring to FIG. 1, one embodiment of an aerosol generating device that can be used in accordance with the present disclosure is shown. The aerosol generating device 10 includes a passageway or opening 12 for receiving a non-combustion heatable stick 14. The aerosol generating device 10 includes a heating device 16 that heats the aerosol-generating material contained in the non-combustion heatable stick 14 without combustion. The heating device 16 may include any suitable heating device capable of heating the non-combustion heatable stick 14 to a temperature sufficient to generate an aerosol. For example, in one embodiment, the heating device 16 comprises an electric heating element, formed of single or multiple heating elements, disposed around or within the aerosol-generating material and powered by a battery. Alternatively, the heating device 16 may be configured to generate heat by burning a fuel such as butane. In yet another embodiment, the heating device 16 may be configured to generate heat by chemically reacting multiple substances with each other.

[0030] As shown in FIG. 1 , the non-combustion heatable cigarette stick 14 can have an appearance similar to a conventional cigarette. If desired, the non-combustion heatable cigarette stick 14 can include a mouthpiece or filter 20. The filter 20 can be made from cellulose acetate tow. In addition to the filter 20, the non-combustion heatable cigarette stick 14 can include an aerosol cooling segment 24. The aerosol cooling segment 24 is designed to reduce the temperature of the aerosol generated from the non-combustion heatable cigarette stick 14. The aerosol cooling segment 24 can be made from a variety of materials, such as cellulose acetate or crimped polylactide film, or a perforated paper tube.

[0031] The non-combustible heat-to-burn stick 14 can further include a column of aerosol-forming material 22. For example, the aerosol-forming material can be tobacco material. The tobacco material can be a single type of tobacco or a blend of various types of tobacco. The aerosol-forming material can be made from natural leaf tobacco, cast leaf tobacco, expanded tobacco, homogenized tobacco, slurry tobacco, paper-reconstituted tobacco, or any combination thereof. The tobacco material can also be combined with various other non-tobacco materials, such as filler particles.

[0032] In addition to tobacco materials, the aerosol-forming material can also include various other materials, such as various other plant materials. For example, in other embodiments, the aerosol-forming material can be made from cannabis, including the buds and flowers of the cannabis plant. In yet other embodiments, the aerosol-forming material can include other non-tobacco plant materials, such as various herbs and flowers.

[0033] In accordance with the present disclosure, the non-combustion heatable stick 14 further includes a wrapper 26 that at least covers the aerosol-forming material 22. The wrapper 26 is made in accordance with the present disclosure and has low flammability. The wrapper 26 may be a single layer of paper or may include two or more layers of paper. Optionally, the non-combustion heatable stick 14 may include a filter 20 and, optionally, tipping paper that covers the aerosol-cooling segment 24.

[0034] Referring to FIG. 2, another embodiment of an aerosol generating device 110 is shown. In this embodiment, a filter 120 and an aerosol cooling segment 124 are incorporated into the aerosol generating device 110. The aerosol generating device 110 includes an opening 112 or mouthpiece through which a user can inhale the aerosol. The aerosol generating device 110 also includes a heating device 116 that heats, without burning, a non-combustion heatable stick 114 loaded into the device. In this embodiment, the non-combustion heatable stick 114 does not include an aerosol cooling segment or a filter. Instead, the non-combustion heatable stick 114 includes a column of aerosol-forming material 122 encased in a wrapper 126 of the present disclosure.

[0035] Referring to Figure 3, yet another embodiment of an aerosol generating device 210 is shown. In this embodiment, the non-combustion heatable stick 14 is substantially the same as the embodiment shown in Figure 1. Accordingly, like reference numerals are used to indicate like elements. The non-combustion heatable stick 14 includes a filter 20, an aerosol cooling segment 24, and an aerosol-forming material 22. The aerosol-forming material 22 is surrounded by a wrapper 26 made in accordance with the present disclosure. In this embodiment, the aerosol generating device 210 includes a heating element, such as a coal system, that heats the non-combustion heatable stick 14 without burning it.

[0036] The aerosol-forming material can contain a humectant for various applications. Humectants that can be used include polyols, non-polyols, or combinations thereof. Polyol humectants include sorbitol, glycerol, propylene glycol, triethylene glycol, or any combination thereof. Non-polyol humectants include lactic acid, glyceryl diacetate, glyceryl triacetate, triethyl citrate, isopropyl myristate, or any combination thereof. The aerosol-forming material can contain one or more humectants in an amount of about 0.1 to 30% by weight. For example, when producing a non-combustion heatable stick, the aerosol-forming material can contain a humectant in an amount greater than about 3% by weight, e.g., greater than about 5%, greater than about 8%, greater than about 10%, greater than about 12%, greater than about 15%, or greater than about 18% by weight, and generally less than about 30% by weight, e.g., less than about 25% or less than about 20% by weight.

[0037] According to the present disclosure, the aerosol-generating material is wrapped in a wrapper. When the aerosol-generating material is wrapped in the wrapper, the non-burning heatable stick typically has a circumferential length of about 4 to 95 mm, e.g., about 4 to 50 mm, or about 8 to 25 mm. The length of the non-burning heatable stick typically can be about 1 to 25 cm, e.g., about 12 to 20 cm, about 3 to 15 cm, or about 4 to 10 cm. The diameter of the non-burning heatable stick can be about 4 to 30 mm, e.g., about 5 to 9 mm. In one embodiment, for example, the diameter of the non-burning heatable stick can be about 5 to 6 mm. In another embodiment, the diameter of the non-burning heatable stick can be about 6.5 to 7.5 mm.

[0038] In one aspect, the paper or wrapper of the present disclosure is made from a substrate web comprising cellulose fibers combined with a flame-retardant filler. The cellulose fibers used to make the substrate web can be formed from softwood fibers, hardwood fibers, flax fibers, any combination thereof, and the like. Generally, any suitable cellulose fibers can be used to make the substrate web. The degree to which the cellulose fibers are refined will vary depending on the application.

[0039] To make the substrate web, cellulose fibers are combined with a flame-retardant filler to form an aqueous suspension, which is then fed through a headbox and deposited onto a moving forming fabric to form an embryonic web, which is then dried.

[0040] In one embodiment, the flame-retardant filler incorporated into the substrate web of the present disclosure is silicate particles, such as metal silicate particles. In one aspect, the metal silicate particles are calcium silicate particles. The calcium silicate particles may generally have an average particle size of greater than about 0.1 μm, for example, greater than about 2 μm or greater than about 3 μm, and generally less than about 30 μm, for example, less than about 20 μm or less than about 10 μm.

[0041] Other examples of filler particles that can be used in accordance with the present disclosure include clay particles, metal hydroxide particles, metal oxide particles, carbonate particles, or any combination thereof. In one aspect, for example, the filler particles can include clay particles. Clay particles particularly suitable for use in the present disclosure include kaolin particles. Metal hydroxide particles are also suitable for use in the present disclosure. For example, in one aspect, the filler particles include aluminum hydroxide particles. In other embodiments, kaolin particles can be combined with aluminum hydroxide particles and / or silicate particles. The filler particles can generally have an average particle size greater than about 0.1 μm, e.g., greater than about 2 μm or greater than about 3 μm, and generally less than about 30 μm, e.g., less than about 20 μm or less than about 10 μm.

[0042] The amount of flame-retardant filler incorporated into the substrate web varies depending on the type of cellulosic fiber contained in the substrate web and on various other factors. Generally, the flame-retardant filler is incorporated into the substrate web in an amount greater than about 10% by weight, e.g., greater than about 15%, about 17%, about 19%, about 21%, or about 23% by weight, and generally less than about 40% by weight of the substrate web, e.g., less than about 35%, about 30%, about 28%, about 26%, or about 24% by weight. In one particular embodiment, the flame-retardant filler is incorporated into the substrate web in an amount between about 16 and 24% by weight.

[0043] In one embodiment, the substrate web can contain the flame-retardant filler in an amount of about 20-45% by weight, such as about 27-38% by weight. In this embodiment, for example, the substrate web may be uncoated; for example, the non-combustible properties of the substrate web can come from the flame-retardant filler alone, rather than from a combination of the flame-retardant filler and a coating.

[0044] In addition to the flame-retardant filler, the substrate web can also contain various other fillers. For example, the substrate web can contain calcium carbonate particles, magnesium oxide particles, calcium chloride particles, calcium lactate particles, calcium gluconate particles, etc. The other fillers can generally be contained in the substrate web in an amount of about 1 to 12% by weight, for example, about 3 to 8% by weight. For example, the substrate web can be configured so that the total filler content is about 40% by weight or less, for example, about 35% by weight or less.

[0045] The inherent air permeability of the substrate web is generally less than about 60 CU. As used herein, the "inherent" air permeability of the substrate web refers to the air permeability of the substrate web in an uncoated state, e.g., before the application of a low-flame-spreading composition. The air permeability of the substrate web can be adjusted using various techniques. For example, the air permeability of the substrate web can be reduced by increasing the amount of refined cellulose fibers and / or decreasing the particle size of one or more fillers. In one embodiment, the air permeability of the substrate web can be relatively low, thereby further improving the flame-retardant properties of the wrapper. For example, the air permeability can be less than about 50 CU, e.g., less than about 30 CU, less than about 25 CU, less than about 20 CU, less than about 15 CU, or less than about 10 CU. The air permeability can generally be about 0 CU or greater, e.g., greater than about 5 CU. In one embodiment, the inherent air permeability of the substrate web can be greater than about 10 CU, e.g., greater than about 20 CU, or greater than about 30 CU.

[0046] The inherent air permeability of the substrate web can be less than about 100 mL / min, for example, less than about 85 mL / min, less than about 70 mL / min, less than about 55 mL / min, less than about 40 mL / min, less than about 30 mL / min, less than about 20 mL / min, or less than about 15 mL / min. The air permeability can be greater than about 5 mL / min, for example, greater than about 10 mL / min or greater than about 25 mL / min. The air permeability in the above units can be measured according to the test method of ISO 5636-3-2013 and is also referred to as Bendtsen air permeability. The air permeability can be measured using an L&W Air Permeability Tester manufactured by Lorentzen & Wettley.

[0047] The basis weight of the substrate web can be about 30 to 100 gsm, including all 1 gsm increments therein. For example, the basis weight of the substrate web can be about 30 to 85 gsm, e.g., about 40 to 80 gsm, or about 45 to 75 gsm. In one aspect, the basis weight of the substrate web can be about 33 to 45 gsm. Alternatively, the basis weight of the substrate web can be about 45 to 60 gsm. In yet another embodiment, the basis weight of the substrate web can be about 60 to 85 gsm, e.g., about 65 to 75 gsm. In other embodiments, the basis weight of the substrate web can generally be about 12 gsm or more and about 60 gsm or less. For example, the basis weight of the substrate web can be greater than about 25 gsm, e.g., greater than about 30 gsm or greater than about 35 gsm, and generally less than about 55 gsm, e.g., less than about 50 gsm or less than about 45 gsm. Basis weight can be measured according to the test method ISO 536:2012. The substrate web is conditioned to 23°C and 50% relative humidity before measurement.

[0048] The substrate webs of the present disclosure may also be treated or include various additives to improve properties or characteristics, such as burn control agents, wet strength agents, oil and / or fat barrier agents, anti-blocking agents, dry strength agents, softening agents, wetting agents, and the like.

[0049] The use of a burn retardant is optional and may not be desirable in various applications. Burn retardants include, for example, salts of carboxylic acids. For example, burn retardants include alkali metal salts of carboxylic acids, alkaline earth metal salts of carboxylic acids, or combinations thereof. Examples of burn retardants that can be used include salts of acetic acid, citric acid, malic acid, lactic acid, tartaric acid, carbonic acid, formic acid, propionic acid, glycolic acid, fumaric acid, oxalic acid, malonic acid, succinic acid, nitric acid, phosphoric acid, or any combination thereof. Specific burn retardants that can be used include salts of potassium citrate, sodium citrate, potassium succinate, sodium succinate, or any combination thereof. When included in the substrate web, one or more burn retardants are typically included in very small amounts. For example, one or more burn retardants can be applied to the substrate web in an amount of less than 1% by weight of the substrate web, e.g., less than about 0.5% by weight or less than about 0.1% by weight. In one embodiment, the substrate web or wrapper of the present disclosure may be completely free of any burn control agents, such as those mentioned above.

[0050] Wet strength agents can reduce the likelihood of degradation of the substrate web when it comes into contact with liquids such as water. Generally, wet strength agents can be selected from polyamides such as epichlorohydrin resins, polyamine-epichlorohydrin resins, poly(aminoamide)-epichlorohydrin resins, urea-formaldehyde resins, melamine-formaldehyde resins; alkyl ketene dimers; alkyl succinic anhydrides; polyvinylamines; oxidized polysaccharides, and the like. Generally, the amount of wet strength agent can be 0.1 to 30%, preferably 1 to 15%, and more preferably 5 to 10%, by dry weight of the wrapper material.

[0051] Antiblocking agents can limit adhesion of the material to the wrapper or paper. Generally, antiblocking agents can be selected from carboxymethyl cellulose, polyacrylamide, acrylates, silicones, and latexes.

[0052] Dry strength agents may increase the resistance of the substrate web when it is subjected to large mechanical stresses. Dry strength agents may be selected from starches and modified gums, cellulose polymers, and synthetic polymers such as carboxymethylcellulose and polyacrylamides. Generally, the amount of dry strength agent may be 0.1-15%, preferably 1-10%, and more preferably 1-5%, by dry weight of the wrapper material.

[0053] The softener can improve the softness of the substrate web. Typically, the softener can be selected from fatty acids, siloxane compounds, silicone compounds, aminosilicone compounds, aloe vera extract, sweet almond extract, chamomile extract, and quaternary ammonium compounds. Typically, the amount of the softener can be 0.1 to 30%, for example 1 to 3%, by dry weight of the substrate web.

[0054] According to the present disclosure, the substrate web described above can optionally be further treated with a flame-reducing composition, for example, the flame-reducing composition can be coated on one or both sides of the substrate web.

[0055] Generally, any suitable flame-spreading-resistant composition can be applied to the substrate web. In one embodiment, for example, the flame-spreading-resistant composition includes a natural or synthetic polymer. For example, flame-spreading-resistant materials that can be used in accordance with the present disclosure include alginates, guar gum, pectin, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives (e.g., ethyl cellulose, methyl cellulose, carboxymethyl cellulose, etc.), starch, and starch derivatives. The flame-spreading-resistant material can also include other cellulosic materials, such as cellulose particles, cellulose fibers, or microcrystalline cellulose (e.g., colloidal microcrystalline cellulose).

[0056] In a particular embodiment, the low-flammability material may include alginate, alone or in combination with starch. Generally, alginate is a derivative of an acidic polysaccharide or gum found in brown seaweed as an insoluble mixed salt of calcium, sodium, potassium, and magnesium. Generally speaking, these derivatives are calcium, sodium, potassium, and / or magnesium salts of high molecular weight polysaccharides composed of varying proportions of D-mannuronic acid and L-guluronic acid. Examples of alginate salts or derivatives include ammonium alginate, potassium alginate, sodium alginate, propylene glycol alginate, and / or any combination thereof.

[0057] In one embodiment, a relatively low molecular weight alginate is used. For example, the alginate may have a viscosity of less than about 500 cP when present in an aqueous solution at 25°C in an amount of 3% by weight. More specifically, the alginate may have a viscosity of less than 250 cP, particularly less than 100 cP, or in one embodiment, a viscosity of about 20-60 cP under the above conditions. As used herein, viscosity is measured using a Brookfield LVF viscometer with an appropriate spindle according to the viscosity. At these low viscosity levels, the alginate composition may be formed with a higher solids content, yet still have a solution viscosity low enough to allow the composition to be applied to a substrate web using conventional techniques. For example, the solids content of an alginate solution produced according to the present disclosure may be greater than about 6% by weight, particularly greater than about 10% by weight, and more particularly about 10-20% by weight.

[0058] At these solids levels, the solution viscosity of the alginate composition can be greater than about 250 cP, preferably greater than about 500 cP, more preferably greater than about 800 cP, or in one embodiment, greater than about 1,000 cP at 25°C. Generally, the solution viscosity of the alginate composition can be adjusted depending on the method of application of the composition to a substrate web. For example, the solution viscosity of the alginate composition can be adjusted depending on whether the composition is sprayed onto paper or printed onto paper.

[0059] It should be understood that in other embodiments, alginates with relatively high molecular weights may be used depending on the application, for example, alginates may have a viscosity of greater than about 500 cP when present in an aqueous solution at 25° C. in an amount of 3% by weight.

[0060] As mentioned above, the low-flame-spreading material may also include a cellulose material, which may be a cellulose slurry (dispersion type) or a cellulose gel. The cellulose material applied to the substrate web may include fibrous cellulose, one or more fillers, and / or cellulose particles. As used herein, cellulose fibers and cellulose particles should be distinguished from derivatized celluloses such as carboxymethyl cellulose. For example, cellulose fibers and cellulose particles are not completely water-soluble.

[0061] In one embodiment, the cellulose material applied to the paper substrate can include microcrystalline cellulose. The microcrystalline cellulose can be ground microcrystalline cellulose, powdered microcrystalline cellulose, or colloidal microcrystalline cellulose. In one aspect, the microcrystalline cellulose is depolymerized colloidal microcrystalline cellulose. Colloidal microcrystalline cellulose forms a gel when combined with water. The microcrystalline cellulose can have an average particle size of less than about 2 μm, e.g., less than about 1 μm, less than about 0.5 μm, or less than about 0.3 μm, and generally greater than about 0.001 μm, e.g., greater than about 0.06 μm.

[0062] In one embodiment, a cellulosic material such as microcrystalline cellulose can be combined with one of the other low-flame-spreading substances listed above, such as alginate, starch, or a combination thereof.

[0063] In one embodiment, the low-flame-spreading composition can further include a viscosity modifier (also called a spacer). The viscosity modifier can be, for example, a cellulose derivative such as carboxymethyl cellulose. The viscosity modifier can generally be contained in the low-flame-spreading composition in an amount of less than about 20% by weight, for example, less than about 15% by weight, less than about 10% by weight, or less than about 5% by weight, and generally in an amount greater than about 1% by weight.

[0064] In one embodiment, the fire-reducing composition includes colloidal microcrystalline cellulose in a gel containing about 8-30% by weight of solids in water. The fire-reducing composition may include, on a dry basis, about 3-8% by weight of calcium carbonate particles, about 2-20% by weight of a cellulose derivative such as the sodium salt of carboxymethylcellulose, and about 60-95% by weight of microcrystalline cellulose.

[0065] The flame-retardant composition applied to the substrate web can contain various other ingredients in addition to alginate, starch, guar gum, pectin, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives, microcrystalline cellulose, cellulose fibers or particles, starch derivatives, or any combination thereof. For example, in one embodiment, as described above, the flame-retardant composition can contain a filler. The filler can be, for example, calcium carbonate, calcium chloride, calcium lactate, calcium silicate, calcium gluconate, or the like. In addition to calcium compounds, magnesium compounds such as magnesium oxide and various other particles, such as clay particles, can be used.

[0066] In one embodiment, the flame-reducing composition can be aqueous. In particular, the flame-reducing composition can comprise an aqueous dispersion, an aqueous gel, or an aqueous solution. Alternatively, the flame-reducing composition before being applied to the paper wrapper can comprise a non-aqueous gel, solution, or dispersion. In this embodiment, for example, alcohol can be present to apply the flame-reducing composition to the wrapper.

[0067] To form a coating, the low-flame spread composition can be applied to the substrate web using any suitable technique. For example, the low-flame spread composition can be applied to the substrate web by spraying, brushing, applying with a moving orifice, or printing. In one embodiment, the low-flame spread composition is applied to the substrate web using gravure printing. The coating can be formed by applying the low-flame spread composition to the substrate web in a single pass or by applying it to the substrate web in multiple passes.

[0068] The amount of the low-flame-spreading composition to be coated on one side of the substrate web can vary depending on the application. In one embodiment, a continuous coating of the low-flame-spreading composition is formed on the surface of the substrate web. For example, the coating can cover more than about 65% of the surface area of ​​one side of the substrate web, such as more than about 80%, more than about 85%, more than about 90%, more than about 95%, or more than about 98%. In a specific embodiment, the low-flame-spreading composition covers 100% of the surface area of ​​one side of the substrate web.

[0069] Alternatively, the coating may be formed in separate regions on one side of the substrate web. In this case, the surface of the substrate web includes coated regions where the flame-spreading composition is applied and uncoated regions where the flame-spreading composition is not applied. For example, the flame-spreading composition may be applied to the surface of the substrate web in any specific pattern. For example, in one embodiment, the flame-spreading composition may be applied to the substrate web in the form of a circumferential band having a width of about 3 to 20 mm. When applied discontinuously, the flame-spreading composition may cover more than about 40%, e.g., more than about 50%, more than about 60%, or more than about 70% of the surface area of ​​one side of the substrate web. Alternatively, when applied discontinuously, the flame-spreading composition may cover less than about 90%, e.g., less than about 80%, of the surface area of ​​one side of the substrate web.

[0070] Generally, the low flame spread composition can be applied to the substrate web in an amount greater than about 0.5 gsm (dry coating weight). The above amount refers to the area where the coating is formed on the substrate web. For example, the basis weight of the coating can be greater than about 1 gsm, e.g., greater than about 4 gsm, greater than about 6 gsm, or greater than about 8 gsm, and generally less than about 10 gsm, e.g., less than about 7 gsm, or less than about 5 gsm. In one embodiment, the coating has a basis weight of about 1 to 5 gsm (when applied to the substrate web).

[0071] A substrate web or wrapper coated with a flame-reducing composition can have a relatively low air permeability in the area covered by the flame-reducing composition. For example, in the covered area, the air permeability of the substrate web can be less than about 10 CU, e.g., less than about 8 CU, less than about 6 CU, less than about 4 CU, less than about 2 CU, or less than about 1 CU. The air permeability in the covered area can be, for example, from about 0 to about 5 CU.

[0072] Within the coated region, the air permeability may be less than about 25 mL / min, such as less than about 20 mL / min, such as less than about 15 mL / min, such as less than about 10 mL / min, or such as less than about 5 mL / min, and generally greater than about 0 mL / min, such as greater than about 0.1 mL / min, or greater than about 1 mL / min.

[0073] In addition to having a relatively low air permeability, the coated region of the substrate web or wrapper also has a relatively low diffusivity. Diffusivity is measured at room temperature (23°C). Typically, the diffusivity of the coated region of the substrate web or wrapper at 23°C is less than about 0.1 cm / s, e.g., less than about 0.05 cm / s, less than about 0.04 cm / s, less than about 0.03 cm / s, or less than about 0.02 cm / s. The diffusivity in the coated region is zero, or typically greater than about 0.0001 cm / s. Diffusivity is measured using a Sodim CO2 Diffusivity Tester.

[0074] A substrate web coated with the low flame spread composition described above can be used alone or in combination with a flame-retardant filler incorporated into the substrate web. However, in some applications, the desired non-flammable properties can be achieved without the use of a flame-retardant filler. For example, in one embodiment, a substrate web manufactured according to the present disclosure can have a continuous coating of a flame retardant composition. The flame retardant composition can include a low flame spread material such as an alginate, a cellulose material such as colloidal microcrystalline cellulose, or a combination thereof. The coating can cover at least about 65%, e.g., about 80%, of the surface area of ​​the substrate web. Within the coated area, the air permeability of the substrate web can be less than about 10 CU, e.g., less than about 5 CU, or less than about 1 CU. The diffusivity within the coated area can be less than about 0.04 cm / s. In this embodiment, the substrate web can be free of filler particles. Alternatively, fillers such as calcium carbonate particles or magnesium oxide particles can be incorporated into the substrate web. The filler can be incorporated into the substrate web in an amount of about 10 to 25% by weight. In one embodiment, the filler may be present in the substrate web in an amount greater than 16% by weight.

[0075] Papers manufactured according to the present disclosure are well suited for use as wrappers for non-combustion heatable sticks. As noted above, the paper of the present disclosure is configured to be non-flammable. When the paper of the present disclosure is used as a wrapper, the wrapper may include a single layer made from the paper of the present disclosure, or may include multiple layers, such as two layers. For example, in one embodiment, the wrapper includes two layers: an inner layer and an outer layer surrounding the inner layer, and the paper of the present disclosure constitutes the inner layer of the wrapper. Alternatively, the paper of the present disclosure may constitute the outer layer of the wrapper.

[0076] The materials (layers) used with the paper of the present disclosure to form the two-layer wrapper can vary depending on the specific situation and desired results. For example, the materials used with the paper of the present disclosure can be formed from cellulosic fibers and can contain fillers such as white fillers formed from calcium carbonate or magnesium oxide. The paper of the present disclosure can also include fillers such as carboxymethyl cellulose, guar gum, or combinations thereof. Optical brighteners can also be incorporated into the paper of the present disclosure.

[0077] After incorporating a wrapper of the present disclosure into a non-combustion heatable stick, the non-combustion heatable stick was tested for flammability. The flammability of a non-combustion heatable stick can be tested, for example, according to the following "flammability test."

[0078] To test for flammability, two sets of 20 non-burning heat sticks were placed in a Borgwaldt RM20 kit machine and tested under static conditions. The non-burning heat sticks were placed horizontally in the device and ignited using a hot wire coil. After ignition, the non-burning heat sticks were allowed to burn under static conditions without puffing. After 15 seconds, a photograph of the burn area was taken, and the burn area was marked (burn line) on the photograph or digital image. Photographs were then taken at 1, 2, and 3 minutes, and the burn area was marked (burn line). If the 3-minute burn line crossed the 15-second burn line, the non-burning heat stick and wrapper were classified as flammable paper. If the 15-second burn line remained unchanged over the 3-minute period, the non-burning heat stick and wrapper were classified as non-flammable paper.

[0079] A non-combustion heatable stick incorporating the paper of the present disclosure can self-extinguish before the three minute period according to the burn test. A non-combustion heatable stick made according to the present disclosure can self-extinguish in less than two minutes, e.g., less than one minute, when tested, for example, using the burn test described above.

[0080] In one embodiment, the flammability of non-combustible heatable sticks can be tested according to the smoking regime conditions of ISO 3308:2012. To test flammability, two sets of 20 non-combustible heatable sticks were placed in a Borgwald RM20 kit machine. The smoking device was smoked with a puff volume of 35 mL + 0.3 for 2 seconds. The puff frequency was once every 60 seconds without airflow interruption. The non-combustible heatable stick was placed in the stick holder of the smoking device and ignited with the first puff. If combustion did not resume with the second puff, the non-combustible heatable stick was considered non-flammable.

[0081] Another test was conducted according to the smoking regime conditions of ISO 20778:2018. In this test, the puff volume was 55 mL + 0.6, and the puff frequency was once every 30 seconds. The puff duration was 2 seconds without airflow interruption. The non-combustion heatable stick manufactured according to the present disclosure can be considered non-combustible based on the results of each of the above tests.

[0082] The present disclosure may be better understood with reference to the following examples.

[0083] Example 1

[0084] Various types of tobacco wrappers were fabricated and incorporated into non-combustible heat-and-burn sticks. Some non-combustible heat-and-burn sticks contained a single layer of tobacco wrapper. In other samples, the tobacco wrapper was a two-layer structure.

[0085] In this example, the aerosol-forming material contained in the non-combustion heat-to-heat stick was a commercially available tobacco material. For samples containing a single layer wrapper, the tobacco material was paper-made reconstituted tobacco. The leaflets were cut and the cut filler was then wrapped in a single layer wrapper. The non-combustible heat stick has a diameter of 5.2 mm and does not include a filter. For samples containing two wrappers, crimped cast leaf tobacco was used. The non-combustible heat stick is 7.3 mm in diameter and contains a filter. The outer layer of the two-layer wrapper was a conventional wrapper used in non-combustible heat-up sticks.

[0086] The inner layers of the two-ply wrapper samples are shown in Table 1 below.

[0087] The following papers were tested using the combustion test described above, and the results are shown in Table 1 below.

[0088] [Table 1]

[0089] 4 and 5 are diagrams showing the combustion tests carried out on the above samples.

[0090] Example 2

[0091] Using the above Paper #9 and Paper #10, non-combustion heatable sticks were manufactured with either a single-layer wrapper or a dual-layer wrapper. The non-combustion heatable sticks were then tested according to the same procedure as in Example 1 (static condition) above. The non-combustion heatable sticks were tested according to ISO test 3308, with the smoking device set to deliver 2-second puffs (35 mL) per minute. Two non-combustion heatable sticks were tested per test. The results are shown in Table 2 below.

[0092] [Table 2]

[0093] As noted above, papers made in accordance with the present disclosure exhibit non-flammability when tested under static conditions. Paper #9 still exhibited strong non-flammability when tested under dynamic conditions.

[0094] Those skilled in the art will recognize that the present invention is susceptible to various modifications and variations without departing from the spirit of the invention, as particularly set forth in the appended claims. Additionally, it should be understood that aspects of the various embodiments may be interchanged, in whole or in part. Furthermore, those skilled in the art will recognize that the foregoing detailed description and examples are for illustrative purposes only and are not intended to limit in any way the scope of the invention, as set forth in the appended claims.

Claims

1. A wrapper for a non-combustion heat-and-serve stick, comprising: a substrate web including a combination of cellulosic fibers and a flame-retardant filler, the substrate web having a first surface and an opposite second surface; a coating formed on the first surface of the substrate web, the coating comprising a low flame spread composition; the flame-retardant filler comprises silicate particles; The silicate particles are contained in the substrate web in an amount of more than 15% by weight and less than 30% by weight, The coating forms an oxygen barrier, wrapper.

2. 10. The wrapper of claim 1, The silicate particles are contained in the substrate web in an amount of 16 to 24 weight percent.

3. 3. A wrapper according to claim 1 or 2, A wrapper wherein the coating is not formed on the silicate particles.

4. A wrapper according to any one of claims 1 to 3, The silicate particles have an average particle size of 0.1 to 30 μm or 2 to 15 μm.

5. A wrapper according to any one of claims 1 to 4, The substrate web has an inherent air permeability of 0 to 50 CU and a basis weight of 12 to 100 gsm.

6. A wrapper according to any one of claims 1 to 5, The coating is continuously formed and covers greater than 80% of the surface area of ​​the first side of the substrate web.

7. A wrapper according to any one of claims 1 to 5, The coating is formed discontinuously, The first surface of the substrate web includes a pattern of areas having the coating and areas not having the coating.

8. A wrapper according to any one of claims 1 to 7, The coating has a basis weight of 0.5 to 10 gsm in the area where the coating is formed.

9. A wrapper according to any one of claims 1 to 8, The wrapper, wherein the low fire spread composition comprises microcrystalline cellulose, alginate, starch, or any combination thereof.

10. A wrapper according to any one of claims 1 to 9, The low flame spread composition includes a combination of a low flame spread material and a viscosity modifier.

11. 11. The wrapper of claim 10, The viscosity modifier comprises carboxymethyl cellulose.

12. A wrapper according to any one of claims 1 to 11, The wrapper is a single layer wrapper.

13. A wrapper according to any one of claims 1 to 11, The wrapper includes multiple layers; The substrate web constitutes one layer of the plurality of layers.

14. A wrapper for a non-combustion heat-and-serve stick, comprising: an outer wrapper comprising cellulose fibers; an inner wrapper including a substrate web; the substrate web comprises a combination of cellulosic fibers and a flame-retardant filler; the flame-retardant filler comprises silicate particles; The silicate particles are contained in the substrate web in an amount greater than 15% by weight and less than 45% by weight.

15. 15. The wrapper of claim 14, The silicate particles are contained in the substrate web in an amount of 27 to 38% by weight.

16. 16. A wrapper according to claim 14 or 15, The silicate particles have an average particle size of 0.1 to 30 μm or 2 to 15 μm.

17. A wrapper according to any one of claims 14 to 16, comprising: A wrapper wherein the substrate web has a basis weight of 20 to 50 gsm.

18. A wrapper according to any one of claims 14 to 17, The substrate web is an uncoated wrapper.

19. A wrapper for a non-combustion heat-and-serve stick, comprising: a substrate web comprising cellulose fibers, the substrate web having a first surface and an opposite second surface; a continuous coating formed on the first surface of the substrate web, the coating comprising a low flame spread composition; the low-fire-spread composition comprises a polymeric material, a cellulosic material, or a combination thereof; the coated area of ​​the first surface of the substrate web has an air permeability of less than 5 CU and a diffusivity of less than 0.04 cm / s; the coating forms an oxygen barrier; Rapper.

20. 20. The wrapper of claim 19, The wrapper, wherein the low fire spread composition comprises alginate, starch, or a combination thereof.

21. 21. A wrapper according to claim 19 or 20, comprising: A wrapper wherein the low flame spread composition covers greater than 40% of the surface area of ​​the first side of the substrate web.

22. A wrapper according to any one of claims 19 to 21, The coating has a basis weight of 0.5 to 10 gsm in the area where the coating is formed.

23. A wrapper according to any one of claims 19 to 22, comprising: The wrapper wherein the substrate web further comprises 10 to 25 weight percent filler particles.

24. 24. The wrapper of claim 23, The wrapper, wherein the filler particles comprise calcium carbonate particles or magnesium oxide particles.

25. A wrapper according to any one of claims 19 to 22, comprising: A wrapper wherein the substrate web does not contain filler particles.

26. A wrapper according to any one of claims 19 to 25, The wrapper is a single layer wrapper.

27. A wrapper according to any one of claims 19 to 25, The wrapper comprises multiple layers; The substrate web constitutes one layer of the plurality of layers.

28. A non-combustion heating stick, a column of aerosol-generating material; A non-combustion heatable stick comprising: a wrapper enclosing the column of aerosol-forming material, the wrapper being as defined in any one of claims 1 to 27.

29. 29. The non-combustion heatable stick according to claim 28, The aerosol-forming material is a non-combustion heat-dispensing stick that contains tobacco.

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