Non-combustible wrapper for heated but not combusted applications

Abstract

A paper is disclosed that is well suited for use as a wrapper in a heat but not burn stick. The paper includes a base web made from cellulose fibers combined with a fire retardant filler and / or can include a coating formed from a reduced ignition point composition.

Description

[0001] Related applications

[0002] This application is based on and claims priority to provisional patent application serial number 63 / 006,576, filed on 7 April 2020, which is incorporated herein by reference. Background Technology

[0003] Smoking products such as cigarettes are typically manufactured by wrapping tobacco sticks in wrapping paper. At one end, the smoking product usually includes a filter through which the product is inhaled. The filter is attached to the smoking product using tipping paper adhered to the white wrapping paper. The wrapping paper and tipping paper used to construct smoking products are typically made of flax or other cellulosic fibers and may contain one or more fillers, such as calcium carbonate.

[0004] When a smoking product is inhaled, mainstream smoke is produced, which is then inhaled through a filter. Mainstream smoke can contain many different components that give the smoking product its specific flavor, including sensations detected not only by a person's taste buds but also by their sense of smell. In addition to producing mainstream smoke, traditional smoking products also produce sidestream smoke. The smoke exhaled by a smoker and the sidestream smoke are commonly referred to as secondhand smoke.

[0005] In recent years, those skilled in the art have created heated tobacco products that can generate aerosols and provide users with the same experience as traditional cigarettes, without producing secondhand smoke. These types of smokeless products are commonly referred to as heated but not burned sticks. Heated but not burned sticks are placed in an aerosol generator and subjected to low-temperature heating, producing an inhalable aerosol without burning the product. For example, a heated but not burned stick may contain tobacco that is heated to generate an aerosol without burning. Similar to conventional smoking products, heated but not burned sticks contain a column of aerosol-generating material surrounded by packaging. The aerosol-generating material can be made in various forms, such as filaments made from different sheets similar to those used in cigarettes, filaments made from aggregated sheets of material, or filaments made from single-sheet filaments. Heated but not burned sticks can be placed in a heating device that heats the stick to a low temperature, for example, from about 200°C to about 450°C. For example, the heating device may use electronic components, may burn fuel, or may initiate a chemical reaction that generates heat.

[0006] In comparison to traditional smoking articles, heat-not-burn sticks should be non-combustible. In particular, heat-not-burn sticks should not be able to hold a lit end when exposed to an open flame or a high-temperature heating element. For example, ideally, heat-not-burn sticks should not be able to be lit and smoked like a traditional cigarette. Furthermore, heat-not-burn sticks preferably do not produce any significant amount of combustion products when placed in a heat-not-burn device. Moreover, various government regulations now require that heat-not-burn sticks cannot be used as traditional cigarettes.

[0007] To address the above issues, in the past, packaging for heat-not-burn sticks has been manufactured by laminating aluminum to a paper substrate. Although aluminum is non-combustible, aluminum can interfere with the ability of the stick to produce a uniform aerosol from end to end. Furthermore, aluminum can significantly increase the cost of the product and is not biodegradable.

[0008] In view of the above, there is a need for improved packaging for heat-not-burn sticks. In particular, there is a need for an improved packaging that can render heat-not-burn sticks non-combustible. SUMMARY

[0009] Generally, the present disclosure relates to a packaging for constructing a heat-not-burn stick. In one aspect, the packaging is non-combustible even when wrapped around a tobacco column and placed in a traditional smoking machine and lit. The packaging of the present disclosure can be made primarily from biodegradable materials and thus is environmentally friendly. Furthermore, the packaging can be constructed so as not to adversely interfere with the aerosol production characteristics of the aerosol generating material contained within the heat-not-burn stick.

[0010] To produce a packaging for heat-not-burn sticks that renders the heat-not-burn stick non-combustible, various techniques can be used alone or in combination. For example, a packaging containing one or more fire-retardant fillers can be manufactured in accordance with the present disclosure. In another aspect, a fire point reduction composition can be applied to one or both sides of the packaging. In yet another aspect, a fire-retardant filler can be used in combination with a coating made from a fire point reduction composition. The packaging of the present disclosure can be made from a single layer of paper or base web or can be made from multiple layers. In one aspect, the packaging contains an outer packaging and an inner packaging, where the inner packaging, the outer packaging, or both are combined with one or more of the above-described techniques.

[0011] In one aspect, the present disclosure relates to a packaging for a heat-not-burn stick. The packaging includes a base web containing cellulose fibers mixed with a fire-retardant filler. The base web has a first side and an opposite second side. The fire-retardant filler can include calcium silicate particles. For example, the calcium silicate particles can be present in the base web in an amount greater than about 10% by weight (e.g., greater than about 16%) and generally less than about 40% by weight (e.g., less than about 30% by weight, such as less than about 24% by weight).

[0012] Alternatively, the flame retardant filler present in the base web can include clay particles, other silicate particles, metal hydroxide particles, and the like. For example, the flame retardant filler can include kaolin particles, aluminum hydroxide particles, or mixtures thereof. Each filler or each filler mixture can be present in the base web in an amount greater than about 10% by weight (e.g., greater than about 16% by weight) and typically less than about 40% by weight (e.g., less than about 30% by weight, e.g., less than about 24% by weight).

[0013] The package further includes a coating disposed on the first side of the base web. The coating includes a burn-reduction composition. For example, the coating can include a burn-reduction substance alone or in combination with a viscosity modifier, a spacer, and / or a filler particle. For example, the burn-reduction substance can include microcrystalline cellulose, alginate, starch, or mixtures thereof. The microcrystalline cellulose can be milled microcrystalline cellulose, powdered microcrystalline cellulose, or colloidal microcrystalline cellulose. In an aspect, the microcrystalline cellulose is depolymerized. The viscosity modifier or spacer can include a cellulose derivative, such as carboxymethylcellulose, guar gum, or any other suitable natural or synthetic polymer.

[0014] As described above, the base web includes a flame retardant filler that includes calcium silicate particles. In an aspect, the calcium silicate particles are uncoated, meaning that the particles are not coated with a different material. Typically, the calcium silicate particles can have an average particle size of about 0.1 microns to about 30 microns, such as about 2 microns to about 15 microns. As used herein, the particle size of the filler can be determined by light scattering or laser diffraction. Such particle size analyzers are commercially available through Horiba Scientific, such as the LA-960 Particle Size Analyzer. The base web can be configured to include only the flame retardant filler or can be configured such that it includes a combination of the flame retardant filler with other fillers.

[0015] The base web can have a basis weight of about 12 gsm to about 80 gsm. The base web can have an intrinsic permeability of about 0 CU to about 50 CU, such as about 0 CU to about 20 CU. As used herein, the “intrinsic” permeability refers to the permeability of the base web prior to the application of any coating or surface treatment (e.g., perforation).

[0016] The coating of the burn-reduction composition can be a continuous coating or a discontinuous coating. As used herein, a continuous coating is a coating that is uninterrupted over the treated area of the substrate. On the other hand, a discontinuous coating is a coating that is interrupted over the treated area, forming untreated areas within the treated area. For example, a package that includes a plurality of spaced apart circumferential bands formed from the coating composition is a discontinuous coating as used herein.

[0017] When the coating is a continuous coating, the coating can generally cover greater than about 40% of the surface area of the first side of the base web, such as greater than about 65%, such as greater than about 80%, such as greater than about 85%, such as greater than about 90%, such as greater than about 95%. Where a coating is provided, the coating can have a basis weight of about 0.5 gsm to about 10 gsm.

[0018] The package according to the present disclosure can be a single layer package or can include multiple layers. For example, the package can include two layers. When multiple layers are included, the base web of the present disclosure comprises one of the layers. For example, in one aspect, the base web can be the inner layer of a two layer package or can be the outer layer of a two layer package.

[0019] In another aspect, a package for a heat-not-burn stick according to the present disclosure includes an outer package comprising cellulose fibers and an inner package comprising a base web. The base web comprises cellulose fibers mixed with a fire retardant filler. For example, the fire retardant filler can be silicate particles, such as calcium silicate particles; clay particles, such as kaolin particles; or metal hydroxide particles, such as aluminum hydroxide particles. The fire retardant filler can be present in the base web in an amount of about 10% to about 45% by weight, such as about 27% to about 38%. The base web can have a basis weight of about 20 gsm to about 50 gsm. In this embodiment, the base web can be uncoated, meaning that the base web is not treated with any burn point reduction composition while still providing the desired non-flammable properties to the package.

[0020] In yet another aspect, the present disclosure is directed to a package for a heat-not-burn stick comprising a base web comprising cellulose fibers. The base web can have a first side and an opposing second side. The base web can include a coating disposed on the first side of the base web, the coating formed from a burn point reduction composition. The coating can be continuous and can cover greater than about 65% of the surface area of the first side of the base web, such as greater than about 80% of the surface area of the first side of the base web. Where coated with the burn point reduction composition, the base web can have a permeability of less than about 10 CU, such as less than about 5 CU, such as less than about 2 CU, and a diffusivity of less than about 0.04 cm / s, such as less than about 0.03 cm / s, such as less than about 0.02 cm / s, where coated. In this embodiment, the base web can optionally comprise filler particles. Where present, the filler particles can comprise calcium carbonate particles or magnesium oxide particles. Alternatively, the base web can be free of any filler material. In this embodiment, the package can be a single layer design or can include multiple layers, with the base web comprising the inner layer of a two layer design.

[0021] The present disclosure also relates to a heated but not burning rod. The heated but not burning rod includes a column of aerosol generating material. The package as described above surrounds the column of aerosol generating material. The aerosol generating material can be made from any suitable plant matter. For example, in one embodiment, the aerosol generating material is tobacco, such as cut rag, cast leaf, or reconstituted leaf produced by a papermaking process. The package of the present disclosure can be incorporated into a heated but not burning rod such that the heated but not burning rod is non-combustible when tested according to the Combustion Test. For example, a heated but not burning rod according to the present disclosure can be extinguished in less than about 3 minutes, such as less than about 2.5 minutes, such as less than about 2 minutes, such as less than about 1.5 minutes, when tested according to the Combustion Test.

[0022] Other features and aspects of the present disclosure are discussed in more detail below. BRIEF DESCRIPTION OF DRAWINGS

[0023] The complete and enabling disclosure of the present disclosure, including the best mode thereof, to which any

[0024] Figure 1 is a plan view of one embodiment of a heated but not burning device according to the present disclosure loaded with a heated but not burning rod;

[0025] Figure 2 is a plan view of an alternative embodiment of a heated but not burning device loaded with a heated but not burning rod;

[0026] Figure 3 is yet another embodiment of a heated but not burning device associated with a heated but not burning rod; and

[0027] Figure 4 and Figure 5 Some results obtained in the following examples are illustrated.

[0028] Reference numerals that are repeated in the description and the drawings are intended to refer to the same or like parts or elements throughout the present disclosure. DETAILED DESCRIPTION

[0029] It will be understood by those within the art that this discussion is merely an example of the disclosure and is not intended to limit the broader aspects of the disclosure.

[0030] Generally, the present disclosure relates to paper products having low combustion properties. For example, the paper products are well suited for use as non-combustible packages to produce heated but not burning rods.

[0031] Low burn characteristics can be incorporated into paper products using a variety of different 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 prepared by incorporating a flame retardant filler, such as silicate particles, into the paper. In another embodiment, the paper product can comprise cellulosic fibers alone or with fillers, and can be coated on one or both surfaces with a burn point reducing composition. For example, the burn point reducing composition can comprise a burn point reducing substance, such as a film-forming polymer or a cellulosic, particulate or fibrous cellulosic material, or a mixture of both. The burn point reducing coating can be used alone or in combination with a flame retardant filler. When incorporated into a wrapper for a heat-not-burn stick, paper manufactured according to the present disclosure can be used in a single layer design. Alternatively, the wrapper can comprise two layers, with paper manufactured according to the present disclosure forming either the outer or inner layer of the wrapper.

[0032] It is particularly advantageous that paper of the present disclosure can be made primarily from biodegradable materials, thereby making the wrapper environmentally friendly while providing the desired non-flammable characteristics for heat-not-burn applications.

[0033] Reference is made to Figure 1 , which shows one embodiment of an aerosol generating device that can be used in accordance with the present disclosure. The aerosol generating device 10 includes a channel or opening 12 for receiving a heat-not-burn stick 14. The aerosol generating device 10 includes a heating device 16 that heats, but does not burn, the aerosol generating material contained within the heat-not-burn stick 14. The heating device can include any suitable heating device capable of exposing the heat-not-burn stick 14 to a temperature sufficient to generate an aerosol. For example, the heating device 16 can include, in one embodiment, an electric heating element that is powered by a battery and can be made of a single or multiple heating elements around or inside the aerosol generating material. Alternatively, the heating device can generate heat by burning a fuel, such as butane. In yet another embodiment, the heating device 16 can include substances that react together in a chemical reaction to generate heat.

[0034] As shown in Figure 1 , the heat-not-burn stick 14 can have an appearance similar to a traditional cigarette. If desired, the heat-not-burn stick 14 can include a mouthpiece or filter 20. The filter 20 can be made of cellulose acetate tow. In addition to the filter 20, the heat-not-burn stick 14 can also include a cooling segment 24. The cooling segment 24 is designed to reduce the temperature of the aerosol generated by the heat-not-burn stick 14. The aerosol cooling segment 24 can be made of a variety of materials, such as cellulose acetate, crimped polylactic acid film, or a perforated paper tube.

[0035] The heat-not-burn stick 14 also includes a column of aerosol generating material 22. For example, the aerosol generating material can be a tobacco material. The tobacco material can be a single variety of tobacco or can be a plurality of tobacco types mixed together. The aerosol generating material can be made from natural tobacco, cast tobacco, expanded tobacco, homogenized tobacco, pulp tobacco, paper reconstituted tobacco, and combinations thereof. The tobacco material can also be combined with various other non-tobacco materials, such as filler granules.

[0036] In addition to tobacco material, the aerosol generating material can include various other materials, such as various other plant materials. For example, in other embodiments, the aerosol generating material can be made from cannabis, including the buds and flowers of the cannabis plant. In yet another embodiment, the aerosol generating material can include other non-tobacco plant material, such as various herbs and flowers.

[0037] According to the present disclosure, the heat-not-burn stick 14 can also include a wrapper 26 that covers at least the aerosol generating material 22. The wrapper 26 is manufactured according to the present disclosure and has low combustion properties. The wrapper 26 can be a single layer of paper or can include two or more layers of paper. Optionally, the heat-not-burn stick 14 can include tipping paper that covers the filter 20 and optionally the aerosol cooling segment 24.

[0038] Referring to Figure 2 , another embodiment of an aerosol generating device 110 is illustrated. In this embodiment, the filter 120 and the aerosol cooling segment 124 are built into the aerosol generating device 110. The aerosol generating device 110 includes an opening 112 or mouthpiece through which a user can receive aerosol. The aerosol generating device 110 includes a heating device 116 that heats but does not burn a heat-not-burn stick 114 loaded into the device. In this embodiment, the heat-not-burn stick 114 does not include an aerosol cooling segment or filter. Rather, according to the present disclosure, the heat-not-burn stick 114 includes a column of aerosol generating material 122 surrounded by a wrapper 126.

[0039] Referring to Figure 3 , yet another embodiment of a heat-not-burn device 210 is illustrated. In this embodiment, the heat-not-burn stick 14 is substantially the same as the embodiment illustrated in Figure 1 . Accordingly, like reference numerals have been used to indicate like elements. The heat-not-burn stick 14 includes a filter 20, an aerosol cooling segment 24, and an aerosol generating material 22. A wrapper 26 manufactured according to the present disclosure encloses the aerosol generating material 22. In this embodiment, the heat-not-burn device 210 includes a heating element, such as a coil system, for providing heat to the heat-not-burn stick 14.

[0040] The aerosol generating material can include a humectant for many applications. Humectants that can be used include polyhydric alcohols, non-polyhydric alcohols, or mixtures thereof. Polyhydric alcohol humectants include sorbitol, glycerin, propylene glycol, triethylene glycol, or mixtures thereof. Non-polyhydric alcohol humectants include lactic acid, glyceryl diacetate, glyceryl triacetate, triethyl citrate, isopropyl myristate, or mixtures thereof. One or more humectants can be present in the aerosol generating material in an amount of about 0.1% to about 30% by weight. For example, when generating a heat-not-burn stick, the aerosol generating material can contain an amount of humectant greater than about 3% by weight (e.g., greater than about 5% by weight, e.g., greater than about 8% by weight, e.g., greater than about 10% by weight, e.g., greater than about 12% by weight, e.g., greater than about 15% by weight, e.g., greater than about 18% by weight), and typically less than about 30% by weight (e.g., less than about 25% by weight, e.g., less than about 20% by weight).

[0041] According to the present disclosure, the aerosol generating material is surrounded by a wrapper. Once the aerosol generating material is wrapped, the circumference of the heat-not-burn stick can generally be from about 4 mm to about 95 mm, e.g., from 4 mm to about 50 mm, e.g., from about 8 mm to about 25 mm. The length of the stick can generally be from about 1 cm to about 25 cm, e.g., from about 12 cm to about 20 cm, e.g., from about 3 cm to about 15 cm, e.g., from about 4 cm to about 10 cm. The diameter of the heat-not-burn stick can be from about 4 mm to about 30 mm, e.g., from about 5 mm to about 9 mm. For example, in one aspect, the diameter can be from about 5 mm to about 6 mm. In an alternative embodiment, the diameter can be from about 6.5 mm to about 7.5 mm.

[0042] In one aspect, the paper or wrapper of the present disclosure is made from a base web comprising cellulosic fibers in combination with a fire retardant filler. The cellulosic fibers used to form the base web can be formed from softwood fibers, hardwood fibers, flax fibers, mixtures thereof, or the like. Generally, any suitable cellulosic fiber can be used to form the base web. The degree of refining of the cellulosic fibers can vary depending on the particular application.

[0043] To form the base web, the cellulosic fibers are combined with the fire retardant filler and formed into an aqueous suspension. The aqueous suspension is then fed through a headbox and deposited onto a moving forming fabric to form an embryonic web, which is then dried.

[0044] In one embodiment, the flame retardant filler combined into the base web according to the present disclosure is a silicate, such as metal silicate particles. In one aspect, the metal silicate particles are calcium silicate particles. The calcium silicate particles can generally have an average particle size greater than about 0.1 microns (e.g., greater than about 2 microns, such as greater than about 3 microns), and generally less than about 30 microns (e.g., less than about 20 microns, such as less than about 10 microns).

[0045] Examples of other filler particles that can be used according to the present disclosure include clay particles, metal hydroxide particles, metal oxide particles, carbonate particles, mixtures thereof, and the like. For example, in one aspect, the filler particles can include clay particles. Clay particles that are particularly suitable for use in the present disclosure include kaolin particles. Metal hydroxide particles are also well suited for use in the present disclosure. For example, in one aspect, the filler particles include aluminum hydroxide particles. In other embodiments, the 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 microns (e.g., greater than about 2 microns, such as greater than about 3 microns), and generally less than about 30 microns (e.g., less than about 20 microns, such as less than about 10 microns).

[0046] The amount of flame retardant filler combined into the base web can vary depending on the type of cellulosic fibers present and based on various other factors. Generally, the flame retardant filler is combined into the base web in an amount greater than about 10% by weight (e.g., greater than about 15% by weight of the base web, such as greater than about 17% by weight, such as greater than about 19% by weight, such as greater than about 21% by weight, such as greater than about 23% by weight), and generally less than about 40% by weight (e.g., less than about 35% by weight, such as less than about 30% by weight, such as less than about 28% by weight, such as less than about 26% by weight, such as less than about 24% by weight). In one particular aspect, the flame retardant filler is combined into the base web in an amount of about 16% to about 24% by weight.

[0047] In one embodiment, the base web can include the flame retardant filler in an amount of about 20% to about 45% by weight (e.g., about 27% to about 38% by weight). In this embodiment, for example, the base web can be uncoated. For example, the non-flammable properties of the base web can come solely from the flame retardant filler without the use of any coating.

[0048] In addition to the flame retardant filler, the base web can include various other fillers. For example, the base web can include calcium carbonate particles, magnesium oxide particles, calcium chloride particles, calcium lactate particles, calcium gluconate particles, and the like. Other fillers can generally be present in the base web in an amount of about 1% to about 12% by weight, such as an amount of about 3% to about 8% by weight. For example, the base web can be constructed such that the total filler loading is about 40% or less by weight, such as about 35% or less by weight.

[0049] The base web can generally have an inherent permeability of less than about 60 CU. As used herein, the "inherent" permeability of the base web refers to the permeability of the base web in an uncoated state (e.g., prior to application of the fire point reduction composition). Various different techniques can be used to control the permeability of the base web. For example, the permeability of the base web can be reduced by increasing the amount of refining of the cellulose fibers and / or reducing the particle size of one or more fillers. In one aspect, the base web has a relatively low permeability, which can further improve the non-flammable properties of the package. For example, the permeability can be less than about 50 CU, such as less than about 30 CU, such as less than about 25 CU, such as less than about 20 CU, such as less than about 15 CU, such as less than about 10 CU. The permeability can generally be about 0 CU or greater, such as greater than about 5 CU. In one aspect, the inherent permeability of the base web can be greater than about 10 CU, such as greater than about 20 CU, such as greater than about 30 CU.

[0050] The inherent permeability of the base web can also be less than about 100 milliliters / minute, such as less than about 85 milliliters / minute, such as less than about 70 milliliters / minute, such as less than about 55 milliliters / minute, such as less than about 40 milliliters / minute, such as less than about 30 milliliters / minute, such as less than about 20 milliliters / minute, such as less than about 15 milliliters / minute. The permeability can be greater than about 5 milliliters / minute, such as greater than about 10 milliliters / minute, such as greater than about 25 milliliters / minute. The permeability in the above units can be determined according to Test Method ISO 5636-3-2013, also known as the Bendtsen permeability. The permeability can be measured using a L&W Air Permeance Tester manufactured by Lorentzen & Wettre Products.

[0051] The basis weight of the base web can be from about 30 gsm to about 100 gsm, including all increments of 1 gsm therebetween. For example, the basis weight can be from about 30 gsm to about 85 gsm, such as from about 40 gsm to about 80 gsm, such as from about 45 gsm to about 75 gsm. In one aspect, the basis weight can be from about 33 gsm to about 45 gsm. Alternatively, the basis weight can be from about 45 gsm to about 60 gsm. In yet another embodiment, the basis weight can be from about 60 gsm to about 85 gsm, such as from about 65 gsm to about 75 gsm. In other embodiments, the basis weight of the base web can generally be about 12 gsm or greater, and about 60 gsm or less. For example, the basis weight can be greater than about 25 gsm (such as greater than about 30 gsm, such as greater than about 35 gsm), and generally less than about 55 gsm (such as less than about 50 gsm, such as less than about 45 gsm). The basis weight can be determined in accordance with Test Method ISO 536:2012. The web is conditioned at 23 °C and 50% relative humidity prior to making the measurement.

[0052] The base web of the present disclosure can also be treated or contain various different additives to improve performance or properties. Additives that can be optionally incorporated into the base web include, for example, 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.

[0053] The use of burn control agents is optional and can not be desired in various applications. For example, the burn control agent can comprise a carboxylate salt. For example, the burn control agent can include an alkali metal salt of a carboxylic acid, an alkaline earth metal salt of a carboxylic acid, or a mixture thereof. Examples of burn control agents that can be used include acetate, citrate, malate, lactate, tartrate, carbonate, formate, propionate, glycolate, fumarate, oxalate, malonate, succinate, nitrate, phosphate, or a mixture thereof. Specific burn control agents that can be used include potassium citrate, sodium citrate, potassium succinate, sodium succinate, or a mixture thereof. When present, generally very small amounts of the burn control agent(s) are used. For example, the burn control agent(s) can be applied to the base web in an amount of less than 1% by weight (such as in an amount of less than about 0.5%, such as in an amount of less than about 0.1%). In one embodiment, the base web or package of the present disclosure can be completely free of any burn control agent, such as the burn control agents described above.

[0054] If the base web is in contact with a liquid, such as water, the wet strength agent can reduce the likelihood of degradation of the base web. Typically, the wet strength agent can be selected from polyamides, such as epichlorohydrin resins, polyamine-epichlorohydrin resins, poly(aminoamide)-epichlorohydrin resins, urea-formaldehyde resins, melamine-formaldehyde resins; alkyl-alkenone dimers; alkyl succinic anhydrides; polyvinyl amines; oxidized polysaccharides. Typically, the amount of wet strength agent is from 0.1% to 30%, preferably from 1% to 15%, even more preferably from 5% to 10% by dry weight of the packaging material.

[0055] Anti-blocking agents can limit the adhesion of the material to the packaging or coated paper. Typically, the anti-blocking agent can be selected from carboxymethyl cellulose, polyacrylamide, acrylates, silicones, and latex.

[0056] If the base web is subjected to large mechanical stresses, the dry strength agent can increase the resistance of the base web. The dry strength agent can be selected from starches and modified gums, cellulosic polymers, synthetic polymers, such as carboxymethyl cellulose and polyacrylamide. Typically, the amount of dry strength agent is from 0.1% to 15%, preferably from 1% to 10%, even more preferably from 1% to 5% by dry weight of the packaging material.

[0057] Softening agents can increase the softness of the base web. Typically, the softening agent is a fatty acid, a silicone compound, a siloxane compound, an aminosilicone compound, an aloe extract, a sweet almond extract, a chamomile extract, a quaternary ammonium compound. Typically, the amount of softening agent is from 0.1% to 30%, such as from 1% to 3% by dry weight of the base web.

[0058] According to the present disclosure, the base web as described above can be optionally further treated with a burn point reducing composition. For example, a coating can be disposed on one or both sides of the base web that contains the burn point reducing composition.

[0059] Typically, any suitable burn point reducing composition can be applied to the base web. For example, in one embodiment, the burn point reducing composition comprises a natural or synthetic polymer. For example, burn point reducing substances that can be used according to the present disclosure include alginates, guar gum, pectin, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives such as ethyl cellulose, methyl cellulose, and carboxymethyl cellulose, starch, starch derivatives and analogs. The burn point reducing substances can also include other cellulose-based materials, such as cellulose particles, cellulose fibers, or microcrystalline cellulose, including colloidal microcrystalline cellulose.

[0060] In one specific embodiment, the ignition point reducing substance can comprise alginate, alone or in combination with starch. In general, alginate is a derivative of an acidic polysaccharide or gum that occurs in the form of insoluble mixed calcium, sodium, potassium and magnesium salts in brown seaweeds of the class Phaeophyceae. In general, these derivatives are calcium, sodium, potassium and / or magnesium salts of high molecular weight polysaccharides composed of different proportions of D-mannuronic acid and L-guluronic acid. Exemplary salts or derivatives of alginic acid include ammonium alginate, potassium alginate, sodium alginate, propylene glycol alginate and / or mixtures thereof.

[0061] In one embodiment, relatively low molecular weight alginate can be used. For example, the alginate can have a viscosity of less than about 500 cP when contained in a 3% by weight aqueous solution at 25°C. More particularly, the alginate can have a viscosity of less than 250 cP, particularly less than 100 cP, and in one embodiment, a viscosity of about 20-60 cP under the above conditions. As used herein, viscosity is determined according to viscosity measurement by a Brookfield LVF viscometer with a suitable spindle. At the above lower viscosity levels, the alginate composition can be formed at a higher solids content, but the solution viscosity is still low enough to allow the composition to be applied to the base web using conventional techniques. For example, the alginate solution prepared according to the present application can have a solids content of greater than about 6% by weight, particularly greater than about 10%, and more particularly from about 10% to about 20%.

[0062] At the above solids content, the solution viscosity of the alginate composition can be greater than about 250 cP, particularly greater than about 500 cP, and more particularly greater than about 800 cP, and in one embodiment, greater than about 1,000 cP at 25°C. In general, the solution viscosity of the alginate composition can be adjusted depending on the manner in which the composition is applied to the base web. For example, the solution viscosity of the composition can be adjusted depending on whether the composition is sprayed onto the paper or printed onto the paper.

[0063] In other embodiments, it will also be appreciated that relatively high molecular weight alginate can be used depending on the application. For example, the alginate can have a viscosity of greater than about 500 cP when contained in a 3% by weight aqueous solution at 25°C.

[0064] As noted above, the ignition point reducing composition can also comprise a cellulosic material, which can be a cellulosic slurry (a dispersion) or a cellulosic gel. The cellulosic material applied to the base web can include fibrous cellulose, one or more fillers and / or cellulose particles. As used herein, cellulose fibers and cellulose particles will be distinguished from derivatized celluloses such as carboxymethyl cellulose. For example, cellulose fibers and cellulose particles are not completely soluble in water.

[0065] In one embodiment, the cellulosic 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 colloidal microcrystalline cellulose that has been depolymerized. The colloidal microcrystalline cellulose can form a gel in combination with water. The microcrystalline cellulose can have an average particle size of less than about 2 microns (e.g., less than about 1 micron, e.g., less than about 0.5 microns, e.g., less than about 0.3 microns), and typically greater than about 0.001 microns (e.g., greater than about 0.06 microns).

[0066] In one embodiment, the cellulosic material (e.g., microcrystalline cellulose) can be combined with one of the other burn-reducing substances identified above, such as alginate, starch, or a mixture thereof.

[0067] In one embodiment, the burn-reducing composition can further include a viscosity modifier (also referred to as a spacer). For example, the viscosity modifier can be a cellulose derivative, such as carboxymethyl cellulose. The viscosity modifier can typically be present in the burn-reducing composition in an amount of less than about 20% by weight (e.g., less than about 15% by weight, e.g., less than about 10% by weight, e.g., less than about 5% by weight), and typically present in the burn-reducing composition in an amount of greater than about 1% by weight.

[0068] In one aspect, the burn-reducing composition includes a gel-like colloidal microcrystalline cellulose that includes about 8% to about 30% solids in water. The composition can include about 3% to about 8% calcium carbonate particles, about 2% to about 20% of a cellulose derivative (such as sodium salt of carboxymethyl cellulose), and about 60% to about 95% microcrystalline cellulose (on a dry basis).

[0069] In addition to alginate, starch, guar gum, pectin, polyvinyl alcohol, polyvinyl acetate, cellulose derivatives, microcrystalline cellulose, cellulose fibers or particles, starch derivatives, or mixtures thereof, the burn-reducing composition applied to the base web can include various other ingredients. For example, in one embodiment, a filler can be included in the composition as described above. The filler can be, for example, calcium carbonate, calcium chloride, calcium lactate, calcium silicate, calcium gluconate, and the like. In addition to calcium compounds, various other particles can be used, including magnesium compounds such as magnesium oxide, clay particles, and the like.

[0070] In one embodiment, the burn-reducing composition can be water-based. In particular, the burn-reducing composition can include an aqueous dispersion, an aqueous gel, or an aqueous solution. Alternatively, the burn-reducing composition prior to application to the paper packaging can include a non-aqueous gel, solution, or dispersion. In this embodiment, for example, an alcohol can be present for application of the composition to the packaging.

[0071] The ignition point reduction composition can be applied to the base web to form a coating using any suitable technique. For example, the ignition point reduction composition can be sprayed, brushed, applied with a moving aperture, or printed onto the base web. In one aspect, the ignition point reduction composition is applied to the base web using gravure printing. The coating can be formed by applying the ignition point reduction composition to the base web in a single pass or using a multiple pass operation.

[0072] The amount of the side of the base web that is coated can vary depending on the particular application. In one embodiment, the ignition point reduction composition forms a continuous coating on the surface of the base web. For example, the coating can cover greater than about 65% of the surface area of the side of the base web, such as greater than about 80% of the surface area, such as greater than about 85% of the surface area, such as greater than about 90% of the surface area, such as greater than about 95% of the surface area, such as greater than about 98% of the surface area of the side of the base web. In a particular embodiment, the ignition point reduction composition can cover 100% of the surface area of the side of the base web.

[0073] Alternatively, the coating can be applied to the side of the base web in discrete regions. In this manner, the base web includes treated regions having the ignition point reduction composition and untreated regions. For example, the ignition point reduction composition can be applied to the surface of the base web in any particular pattern. For example, in one embodiment, the ignition point reduction composition can be applied to the base web in the form of a circumferential band having a width of from about 3 mm to about 20 mm. When applied in a discontinuous manner, the ignition point reduction composition can cover greater than about 40% of the surface area of the side of the base web, such as greater than about 50%, such as greater than about 60%, such as greater than about 70%. When applied in a discontinuous manner, the ignition point reduction composition can cover less than about 90% of the surface area of the side of the base web, such as less than about 80%.

[0074] Generally, the ignition point reduction composition can be applied to the base web in an amount of greater than about 0.5 gsm (dry coating weight). The above amounts are directed to the area of the base web that is coated. For example, the coating can have a basis weight of greater than about 1 gsm (such as greater than about 4 gsm, such as greater than about 6 gsm, such as greater than about 8 gsm) and generally less than about 10 gsm (such as less than about 7 gsm, such as less than about 5 gsm). In one embodiment, the coating has a basis weight of from about 1 gsm to about 5 gsm (when applied to the base web).

[0075] Once coated, the base web or package can have a relatively low permeability within the coated area. For example, the base web can have a permeability of less than about 10 CU, such as less than about 8 CU, such as less than about 6 CU, such as less than about 4 CU, such as less than about 2 CU, such as less than about 1 CU within the coated area. For example, the permeability within the coated area can be from about 0 CU to about 5 CU.

[0076] Within the coated area, the permeability can 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, such as less than about 5 ml / min) and generally greater than about 0 (such as greater than about 0.1 ml / min, such as greater than about 1 ml / min).

[0077] In addition to having a relatively low permeability, the coated area of the base web or package has a relatively low diffusivity. The diffusivity can be measured at room temperature (23 °C). Generally, the coated area of the base web or package has a diffusivity of less than about 0.1 cm / s at 23 °C, such as less than about 0.05 cm / s, such as less than about 0.04 cm / s, such as less than about 0.03 cm / s, such as less than about 0.02 cm / s. The diffusivity of the coated area is zero or generally greater than about 0.0001 cm / s. The diffusivity is measured using a Sodim CO2 Diffusivity Tester.

[0078] A base web coated with a burn-reducing composition as described above can be used alone or in combination with a flame retardant filler that is combined into the base web. However, in some applications, the use of a flame retardant filler can not be desired to achieve the desired non-flammable properties. For example, in one embodiment, a base web manufactured according to the present disclosure can include a continuous coating of a flame retardant composition. The flame retardant composition can include a burn-reducing substance (such as alginate), a cellulosic material (such as colloidal microcrystalline cellulose), or can include a combination of materials. The coating can cover at least about 65% of the surface area of the base web, such as at least about 80% of the surface area of the base web. Within the coated area, the base web can have a permeability of less than about 10 CU, such as less than about 5 CU, such as less than about 1 CU. The diffusivity within the coated area can be less than about 0.04 cm / s. In this embodiment, the base web can be free of any filler particles. Alternatively, a filler can be combined into the base web, such as calcium carbonate particles, magnesium oxide particles, and the like. The filler can be incorporated into the base web in an amount of about 10% to about 25% by weight. In one aspect, the filler can be present in the base web in an amount greater than 16% by weight.

[0079] The paper manufactured according to the present disclosure is well suited for use as a wrapper for a heat, but not burn, stick. As noted above, the paper can be configured such that the paper is non-flammable. When combined into a wrapper, the wrapper can contain a single layer made of paper or can include multiple layers, such as two layers. For example, in one embodiment, the wrapper can include two layers, and the paper of the present disclosure can be an inner layer surrounded by an outer layer. Alternatively, the coated paper can be an outer layer surrounding an inner layer.

[0080] The paper wrapper used in combination with the paper of the present disclosure to form a two layer wrapper can vary depending on the circumstances and desired results. For example, the opposing layer can be made of cellulose fibers and can contain a filler, such as a white filler made of calcium carbonate or magnesium oxide. The paper can also contain a binder, such as carboxymethyl cellulose, guar gum, or a mixture thereof. A fluorescent whitening agent can also be incorporated into the paper.

[0081] Once the wrapper according to the present disclosure is combined into a heat, but not burn, stick, the heat, but not burn, stick can be tested for flammability. For example, the heat, but not burn, stick can be tested according to the "burn test" as follows.

[0082] To test for flammability, two groups of 20 heat, but not burn, sticks can be placed in a Borgwaldt RM20 suite machine and tested according to static conditions. The heat, but not burn, sticks are placed in a horizontal position in the smoking machine described above and then ignited using a hot wire coil. After the heat, but not burn, stick is ignited, no puff is administered and the heat, but not burn, stick is allowed to burn (or extinguish) under static conditions. After 15 seconds, a photograph of the burning area is taken. The burning area is marked on the photograph or digital image. Photographs are then taken after one minute, two minutes, and three minutes. The marks corresponding to the burning line after 15 seconds are placed on the photographs taken after one minute, two minutes, and three minutes, respectively. After three minutes, if the burning line has crossed the area marked previously, the heat, but not burn, stick and wrapper are classified as flammable paper. If the originally drawn burning line has not changed within three minutes, the heat, but not burn, stick and wrapper are classified as non-flammable.

[0083] The heat, but not burn, sticks that combine the coated paper of the present disclosure can self-extinguish prior to the three minute time interval according to the burn test. For example, when tested using the test described above, the heat, but not burn, sticks manufactured according to the present disclosure can self-extinguish in less than two minutes, such as less than one minute.

[0084] In one aspect, the heat-not-burn sticks can be tested according to ISO 3308:2012 smoking regime conditions. To test combustibility, two sets of 20 heat-not-burn sticks can be placed into a Borgwaldt RM20 suite machine for testing. The smoking machine puffs at a draw volume of 35 mL ± 0.3, with a 2 second puff duration. The puff frequency is once every 60 seconds, without blocking the ventilation. The heat-not-burn sticks are inserted into the stick holder of the machine and lit with the first puff. If the second puff does not re-ignite the heat-not-burn stick is considered non-combustible.

[0085] Another test is performed according to ISO 20778:2018 smoking regime conditions, with a puff volume of 55 mL ± 0.6, and a puff frequency of once every 30 seconds. The puff duration is 2 seconds, without blocking the ventilation. Heat-not-burn sticks made according to the present disclosure can be considered non-combustible in each of the above tests.

[0086] The present disclosure can be better understood with reference to the following examples.

[0087] First Example

[0088] Various different tobacco wrappers were made and combined into heat-not-burn sticks. Some of the heat-not-burn sticks included a tobacco wrapper with a single layer. In other samples, the tobacco wrapper was a two-layer structure.

[0089] In this example, the aerosol generating material contained within the heat-not-burn sticks was a commercially available tobacco material. For samples containing a single layer wrapper, the tobacco material was paper reconstituted tobacco. The cut filler was slit into small leaves and then wrapped with a single layer wrapper. The sticks had a diameter of 5.2 mm and did not contain a filter. For samples containing a double layer wrapper, crimped cast leaf was used. The heat-not-burn sticks had a diameter of 7.3 mm and included a filter. The overwrap used was a conventional overwrap for heat-not-burn sticks.

[0090] In the two-layer wrapper samples, the inner layer is described in the table below.

[0091] The following papers were tested according to the burn test as described above. The following results were obtained:

[0092]

[0093]

[0094] Figure 4 and Figure 5 are graphical representations of the burn test performed on each of the samples described above.

[0095] Second Example

[0096] Paper No. 9 and No. 10 above were used to produce heat-not-burn sticks in single and double pack configurations. The heat-not-burn sticks were then tested according to the same procedure as in Example 1 above (static conditions). The heat-not-burn sticks were also tested according to ISO test 3308, with the smoking machine set to draw for two seconds (35 mL) per minute. Two heat-not-burn sticks were tested each time. The following results were obtained.

[0097]

[0098] (n / n): number of sticks in category (combustible or non-combustible) / number of sticks evaluated

[0099] As shown above, the paper manufactured according to the present disclosure showed non-combustible properties when tested according to static conditions. When tested according to dynamic conditions, Paper No. 9 still showed strong non-combustible properties.

[0100] These and other modifications and variations to the present application can be practiced by persons of ordinary skill in the art having the benefit of this disclosure without departing from the spirit and scope of the present application, which is defined by the following claims. Furthermore, aspects of the various embodiments can be interchanged either in whole or in part. Moreover, it should be appreciated that the descriptions set forth herein are by way of example and not intended to limit the present application, as described in the appended claims.

Claims

1. A non-combustible packaging material for a heated but non-burning rod, comprising: A base web comprising cellulose fibers in combination with flame-retardant filler, the base web having a first side and an opposite second side, the flame-retardant filler comprising silicate particles, the silicate particles being greater than 16% and less than 24% by weight of the base web; as well as A coating disposed on the first side of the base web, the coating comprising a flash point lowering composition, the coating forming an oxygen barrier.

2. The packaging as claimed in claim 1, wherein, The silicate particles are uncoated.

3. The packaging as claimed in claim 1, wherein, The average particle size of the silicate particles is 0.1 micrometers to 30 micrometers.

4. The packaging as claimed in claim 1, wherein, The inherent permeability of the base web is 0 CU to 50 CU, and the basis weight is 12 gsm to 100 gsm.

5. The packaging as claimed in claim 1, wherein, The coating of the ignition point lowering composition is continuous, the first side of the base web has a surface area, and wherein the coating covers more than 80% of the surface area of ​​the first side of the base web.

6. The packaging as claimed in claim 1, wherein, The coating of the ignition point lowering composition is discontinuous, and the first side of the base web includes a pattern of coated and uncoated areas.

7. The packaging as claimed in claim 1, wherein, The coating has a basis weight of 0.5 gsm to 10 gsm in the area where the coating is applied.

8. The packaging as claimed in claim 1, wherein, The ignition point lowering composition comprises microcrystalline cellulose, alginate, starch, or a mixture thereof.

9. The packaging as claimed in claim 1, wherein, The ignition point lowering composition comprises an ignition point lowering substance in combination with a viscosity modifier.

10. The packaging as claimed in claim 9, wherein, The viscosity modifier includes carboxymethyl cellulose.

11. The packaging as claimed in claim 1, wherein, The packaging material is a single-layer packaging material.

12. The packaging as claimed in claim 1, wherein, The packaging material comprises multiple layers, and the base web comprises one of the layers.

13. A non-combustible packaging material for a heated but non-burning rod, comprising: Outer packaging containing cellulose fibers; as well as An inner packaging comprising a base web comprising cellulose fibers combined with a flame-retardant filler comprising silicate particles, the silicate particles comprising more than 27% and less than 38% by weight of the base web.

14. The packaging as claimed in claim 13, wherein, The average particle size of the silicate particles is 0.1 micrometers to 30 micrometers.

15. The packaging as claimed in claim 13, wherein, The base web has a basis weight of 20 gsm to 50 gsm.

16. The packaging as claimed in claim 13, wherein, The base web is uncoated.

17. A non-combustible packaging material for a heated but non-burning rod, comprising: A base web comprising cellulose fibers, the base web having a first side and an opposing second side; as well as A continuous coating disposed on a first side of the base web, the coating comprising a flash point lowering composition comprising a polymeric material, the base web having a permeability of less than 5 CU and a diffusion rate of less than 0.04 cm / s at the location where the flash point lowering composition is coated, the first side of the base web having a surface area, and wherein the flash point lowering composition covers more than 40% of the surface area of ​​the first side of the base web, the coating forming an oxygen barrier.

18. The packaging as claimed in claim 17, wherein, The flash point lowering composition comprises alginate, starch, or a mixture thereof.

19. The packaging as claimed in claim 17, wherein, The ignition point lowering composition covers more than 40% of the surface area of ​​the first side of the base web.

20. The packaging as claimed in claim 17, wherein, The coating has a basis weight of 0.5 gsm to 10 gsm in the area where the coating is applied.

21. The packaging as claimed in claim 17, wherein, The base web also contains 10% to 25% filler particles by weight.

22. The packaging as claimed in claim 21, wherein, The filler particles include calcium carbonate particles or magnesium oxide particles.

23. The packaging as claimed in claim 17, wherein, The base web does not contain any filler particles.

24. The packaging as claimed in claim 17, wherein, The packaging material is a single-layer packaging material.

25. The packaging as claimed in claim 17, wherein, The packaging material comprises multiple layers, and the base web comprises one of the layers.

26. The packaging as claimed in claim 17, wherein, The polymer material is a cellulose material.

27. A heating but non-burning rod, comprising: Aerosol generating material column; as well as The non-flammable packaging as claimed in claim 1, wherein the non-flammable packaging generates a column of material around the aerosol.

28. The heated but non-combustible rod as claimed in claim 27, wherein, The aerosol-generating material includes tobacco.

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