Filter products with high moment of inertia

Abstract

A filter product for use in consumer products. The consumer products can include tobacco products such as combustible cigarettes and heat-not-burn sticks. The filter product can include a plurality of cellulose acetate fibers having a hollow core portion.

Description

[Technical field]

[0001] The present invention relates to the field of filters, and more particularly to filter products formed from fibers having a hollow core, such filter products being adapted for use in consumer products. [Background technology]

[0002] As will be described in more detail below, various types of consumer products, such as tobacco products, require the use of filters. A typical tobacco product filter, e.g., a cigarette filter, is made from a continuous filament tow band of cellulose acetate-based fibers, commonly referred to as cellulose acetate tow (sometimes referred to herein as "CA tow"). The use of CA tow to make filters is described in various patents, and the CA tow can be plasticized. See, for example, U.S. Pat. No. 2,794,239. Instead of continuous fibers, staple fibers may be used, which are shorter and can aid in the eventual disintegration of the filter. See, for example, U.S. Pat. No. 3,658,626, which discloses the manufacture of staple fiber filter elements directly from continuous filament tow. These staple fibers can also be plasticized.

[0003] CA tow for combustible cigarette filters is typically composed of small filament denier fibers that are intentionally highly crimped and entangled with a solid cross section, as described in U.S. Pat. No. 2,953,838. Such fibers are generally solid cross sections, e.g., (i) "Y" shaped, or (ii) round / circular. In constructing the filter, the crimping of the fibers improves the filter's stiffness and reduces the weight of the tow for a given pressure drop. Converting CA tow into tobacco product filters can be accomplished by a tow conditioning system and a plug maker, as described, for example, in U.S. Pat. No. 3,017,309. The tow conditioning system draws the CA tow from the bale, spreads and displaces the fibers ("blooms"), and delivers the tow to the plug maker, which compresses the tow, wraps it in plug wrap paper, and cuts it into rods of appropriate length. When such plug-type filters are formed, they are generally shaped as rods or cylindrical rods, with the cellulose acetate fibers running through the interior of the rod to form a solid cross section. In some alternative embodiments, the filters are formed as hollow cylinders or tubes, with the cellulose acetate fibers running through only a portion of the interior of the tube to form a hollow cross section. Specifically, such hollow tubes can have an inner diameter and an outer diameter, with a wall thickness extending between the inner and outer diameters. Thus, the cellulose acetate fibers generally run across the wall of the hollow tube (i.e., between the inner and outer diameters).

[0004] Filters are generally understood to be one of the most expensive components of a tobacco product. However, the presence of a filter is necessary to at least partially remove undesirable volatile particles or other particulate material from tobacco smoke and aerosols. As such, a common proposal to reduce the cost of tobacco product filters is to reduce the amount of CA tow or fiber in the filter. Unfortunately, reducing the amount of CA tow or fiber in a filter has previously resulted in undesirable filter properties, especially when using the common Y-shaped fiber. For example, reducing the amount of CA tow or fiber in a filter has been found to result in a filter that is too soft (i.e., low hardness / rigidity), uneven structure formation, and unacceptable visual defects. Similarly, reducing the amount of CA tow or fiber in a filter has been found to result in an unacceptably low pressure drop through the filter during use of the tobacco product.

[0005] Another proposed option for reducing the costs associated with filters is to increase the production speed of the filters to reduce overall downtime and costs, however, due to the high friction characteristics of commonly used fibers (such as Y-shaped fibers), it has been found that increasing production speeds increases maintenance and / or breakdowns of the manufacturing machinery, as well as structural failures of the filters.

[0006] In view of the above, there remains a need in the art for consumer product filters that can be manufactured at low cost and that do not exhibit unacceptable functional or aesthetic properties. More specifically, there is a need in the art for consumer product filters that can be manufactured with fewer fibers and that exhibit appropriate levels of firmness, pressure drop, and manufacturing quality. Summary of the Invention

[0007] One aspect of the present invention relates to a filter product for use in a consumer product. The filter product comprises a plurality of cellulose acetate fibers having a hollow core portion. The fibers have an average diameter of at least 50,000 μm. 4 It has an area moment of inertia of

[0008] Another aspect of the invention relates to a filter product for use in a consumer product. The filter product includes a plurality of cellulose acetate fibers having a hollow core portion. The fibers have a fiber-to-metal coefficient of friction of 0.565 or less.

[0009] Another aspect of the invention relates to a filter product for use in a consumer product. The filter product comprises a plurality of cellulose acetate fibers having a hollow core portion. The fibers have a fiber-to-fiber coefficient of friction of 0.135 or less.

[0010] Another aspect of the invention relates to a consumer product comprising a tobacco and a filter product. The filter product comprises a plurality of cellulose acetate fibers having a hollow core portion.

[0011] Another aspect of the invention relates to a combustible cigarette comprising tobacco and a filter product, The filter product comprises a plurality of cellulose acetate fibers having a hollow core portion.

[0012] Another aspect of the invention relates to a heat-no-burn stick comprising tobacco and a filter product, the filter product comprising a plurality of cellulose acetate fibres having a hollow core portion.

[0013] Another aspect of the invention relates to a filter product for use in a consumer product. The filter product includes a hollow tube formed from a plurality of cellulose acetate fibers having a hollow core portion. The hollow tube has an inner diameter and an outer diameter. The mass of the cellulose acetate within the hollow tube is 495 mg or less, and the hollow tube has a hardness of at least 92.0% (Borgwaldt 3Kg).

[0014] Another aspect of the invention relates to a filter product for use in a consumer product. The filter product includes a hollow tube formed from a plurality of cellulose acetate fibers having a hollow core portion. The hollow tube has an inner diameter and an outer diameter. The mass of the cellulose acetate within the hollow tube is 495 mg or less, and the hollow tube has a hardness of at least 92.2% (Borgwaldt 3Kg).

[0015] Another aspect of the invention relates to a filter product for use in a consumer product. The filter product includes a hollow tube formed from a plurality of cellulose acetate fibers having a hollow core portion. The hollow tube has an inner diameter and an outer diameter. The mass of the cellulose acetate within the hollow tube is 497 mg or less, and the hollow tube has a hardness of at least 92.4% (Borgwaldt 3 Kg).

[0016] Another aspect of the invention relates to a filter product for use in a consumer product, the filter product comprising a tubular rod formed from a plurality of cellulose acetate fibers having a hollow core portion, the mass of the cellulose acetate within the hollow tube being less than or equal to 560 mg, and the hollow tube having a hardness of at least 83.0% (Borgwaldt 3Kg).

[0017] Another aspect of the invention relates to a filter product for use in a consumer product, the filter product comprising a tubular rod formed from a plurality of cellulose acetate fibers having a hollow core portion, the mass of cellulose acetate within the hollow tube being less than or equal to 540 mg, and the hollow tube having a hardness of at least 83.5% (Borgwaldt 3Kg).

[0018] Another aspect of the invention relates to a filter product for use in a consumer product, the filter product comprising a tubular rod formed from a plurality of cellulose acetate fibers having a hollow core portion, the mass of cellulose acetate within the hollow tube being less than or equal to 580 mg, and the hollow tube having a hardness of at least 84.5% (Borgwaldt 3Kg). [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a transverse cross-sectional view of a solid cylindrical rod filter for a tobacco product.

[0020] [Diagram 2] FIG. 2 is a transverse cross-sectional view of a hollow cylindrical tube for a tobacco product.

[0021] [Diagram 3] FIG. 3 is a longitudinal cross-section of a combustion cigarette with a filter product in the form of a solid cylindrical rod filter at the tip of the cigarette.

[0022] [Figure 4] FIG. 4 is a longitudinal cross-sectional view of a combustion cigarette with a filter product having a solid cylindrical rod filter at the tip of the cigarette.

[0023] [Diagram 5] FIG. 5 is a longitudinal cross-section of a combustion cigarette with an alternative filter product having a solid cylindrical rod filter at the end of the cigarette.

[0024] [Figure 6] FIG. 6 is a longitudinal cross-sectional view of a combustion cigarette with a filter product having a hollow cylindrical tube at the tip of the cigarette and a solid cylindrical rod filter disposed between the hollow cylindrical filter and the tobacco portion.

[0025] [Figure 7] FIG. 7 is a longitudinal cross-sectional view of a combustion cigarette with another filter product having a hollow cylindrical hollow tube at the tip of the cigarette and a solid cylindrical hollow rod filter disposed between the hollow cylindrical filter and the tobacco portion.

[0026] [Figure 8]FIG. 8 is a longitudinal cross-sectional view of a heat-and-non-burn stick cigarette with a filter product having a solid cylindrical rod filter at the mouthpiece of the heat-and-non-burn stick cigarette.

[0027] [Figure 9] FIG. 9 is a longitudinal cross-sectional view of a heat-and-burn stick with another filter product having a solid cylindrical rod filter at the mouthpiece of the heat-and-burn stick.

[0028] [Figure 10] FIG. 10 is a longitudinal cross-sectional view of a heat-and-burn stick-type tobacco product having a solid cylindrical rod filter at the mouthpiece of the heat-and-burn stick-type tobacco product and another filter product having a hollow cylindrical tube disposed between the solid cylindrical filter and the tobacco portion.

[0029] [Figure 11] FIG. 11 is a longitudinal cross-sectional view of a heat-and-burn stick with another filter product having a first hollow cylindrical hollow tube at the mouthpiece of the heat-and-burn stick and a second hollow cylindrical hollow tube disposed between the first hollow cylindrical hollow tube and the tobacco portion.

[0030] [Figure 12] FIG. 12 is a longitudinal cross-sectional view of a heat-and-burn stick-type tobacco product having a solid cylindrical rod filter at the mouthpiece of the heat-and-burn stick-type tobacco product, a first hollow cylindrical tube arranged adjacent to the solid cylindrical rod filter, and a second hollow cylindrical tube arranged between the first hollow cylindrical tube and the tobacco portion.

[0031] [Figure 13] FIG. 13 is a transverse cross-section of a fiber / filament having a closed C-shape.

[0032] [Figure 13A] FIG. 13A is a transverse cross-section of another fiber / filament having a closed C-shape.

[0033] [Figure 13B] FIG. 13B is a transverse cross-section of a fiber / filament that does not have a closed C-shape.

[0034] [Figure 14] FIG. 14 is a transverse cross-section of the fiber / filament of FIG. 13, further illustrating the principal moments of inertia of the fiber / filament.

[0035] [Figure 15] FIG. 15 is a pressure drop capacity curve for three sets of rod filters having various cross-sectional geometries.

[0036] [Figure 16] FIG. 16 is a stiffness capacity curve for three sets of rod filters having various cross-sectional geometries.

[0037] [Figure 17] FIG. 17 is a hardness capability curve for three sets of hollow tubes having various cross-sectional geometries. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Glossary Cigarette - A thin cylinder of finely cut tobacco rolled in paper for smoking by the user.

[0039] Denier per Filament - A textile unit of measurement corresponding to the weight in grams of an individual filament at a length of 9,000 meters.

[0040] Fiber- Single filament.

[0041] Fiber-to-fiber friction coefficient - The ratio of the frictional force resisting the movement of two fiber surfaces in contact to the normal force pressing the two surfaces together.

[0042] Fiber-to-Metal Coefficient of Friction - The ratio of the frictional force resisting the movement of two surfaces in contact, specifically a fiber surface and a metal surface, to the normal force pressing the two surfaces together.

[0043] Filament- A thin, continuous wire-like object.

[0044] Filter Product - a single component or two or more components forming an assembly used individually or in combination with other components to perform primarily a filtration function. It should be noted that although a filter product is used primarily to perform a filtration function, the filter product (or specific components thereof) may perform other functions, such as temperature management or pressure regulation functions.

[0045] Rod Filter - A cylindrical rod formed from multiple fibers.

[0046] Hollow Tube - A hollow tube whose walls are formed by multiple fibers.

[0047] Heated Non-Combustion Stick - A non-combustion, multi-segmented assembly that uses precisely controlled heat to vaporize material, producing an aerosol that can be consumed by the user.

[0048] Moment of Inertia - A property of a cross-sectional shape or area used to predict deflection, bending and stress caused by a load. Moment of inertia is calculated by multiple integrals of the area. Specifically, the principal moments of inertia of an area A lying in the XY plane are calculated by dividing the area A by the center of gravity (μm 4 ) can be calculated.

number

[0049] Total Denier - A textile unit of measurement corresponding to the product of the denier per filament and the number of filaments in a tow or yarn.

[0050] Tow - A band of multiple continuous filaments.

[0051] Yarn- A bundle of filaments.

[0052] The following embodiments of the present invention will be described in more detail with reference to the accompanying drawings. While the drawings illustrate various embodiments of the present invention, such illustrations and descriptions are by way of example only. It is not intended that the principles and scope of the present invention be limited to the specifically described embodiments, but instead by the scope of the following claims.

[0053] As used herein, relative terms such as "first", "second", "top" or "upper", "lower" or "lower" are used for clarity and convenience in understanding the disclosure and accompanying drawings, and do not imply or depend on any particular preference, direction or order unless the context clearly indicates otherwise. As used herein, the terms "about" and "substantially" with respect to a given parameter, characteristic or condition mean that the given parameter, characteristic or condition is met with minor variations, such as within acceptable measurement and / or manufacturing tolerances, and generally include up to a 5% variation of the specified value. For example, the term "about 1.0" includes a range of variation of 0.95 to 1.05. A series of numbers includes an adjective that precedes or follows the number. For example, at least 1, 2, 3 denier per filament ("dpf") includes at least 1 dpf, or at least 2 dpf, or at least 3 dpf. All numbers or percentages relating to amounts of substances in this description are given as percentages by weight (wt.%) unless expressly stated to the contrary or clear from the context.

[0054] The present invention is directed to a filter product for consumer products. The term "consumer product" generally refers to any type of product that is used by an end user (e.g., a consumer) and allows the user to experience (e.g., inhale) an aerosolized substance. Thus, consumer products include tobacco products, botanical products, and the like. Tobacco products include combustible products such as cigarettes, as well as non-combustible products such as heat-not-burn sticks and e-cigarettes. In these tobacco products, the type of tobacco material used is not particularly limited, such as tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco, tobacco substitutes, non-combustible products, and the like, and mixtures thereof. Botanical products can include products configured to produce vaporized plant and / or other non-tobacco biological substances.

[0055] These consumer products may often be provided with filter products in the form of a single filter element and / or a filter assembly. In some instances, the filter products may include a plug formed from a fibrous material. More specifically, the plug may be shaped as a cylindrical rod (referred to herein as a "rod filter"). As shown in FIG. 1, the fibrous material of the rod filter 10 may extend throughout the interior of the rod filter 10 such that the rod filter 10 has a generally solid cross-section. The rod filter 10 may have an outer diameter "d ext For example, in some embodiments, the outer diameter d ext Rod filters 10 having an outer diameter d of more than 7.00 mm can be considered to be of "normal" size. ext A rod filter 10 having an outer diameter d of 6.00 to 7.00 mm can be considered to be of "slim" size. ext Rod filters 10 having a diameter of 5.40 to 5.99 mm can be considered "micro-slim" size.

[0056] In addition to the rod filter 10, certain tobacco products may incorporate a filter product that includes a hollow cylindrical tube (herein referred to as a "hollow tube"). As shown in FIG. 2, the hollow tube 12 has an inner diameter "d int " and the outer perimeter "C ext The inner diameter is generally non-zero, such that hollow tube 12 encloses an open interior space. The walls of the hollow tube extend from the inner surface to the outer surface of the tube and thus have a thickness "T wall The fiber material of the hollow tube 12 generally has a wall thickness T wall As such, hollow tube 12 has a generally hollow cross section. Hollow tube 12 has an outer diameter "C ext The hollow tube 12 may be machined to various sizes, such as 12.0 to 28.00 mm, 14.00 to 26.00 mm, 16.00 to 24.00 mm, and / or 18.00 to 22.00 mm. Further, the hollow tube 12 may have a wall thickness T wall can be 0.2 mm to 1.8 mm, 0.4 mm to 1.6 mm, 0.6 mm to 1.4 mm, and / or 0.8 mm to 1.2 mm. Although Figure 2 shows hollow tube 12 having a generally circular or cylindrical hollow interior space, it should be understood that the hollow interior space may be fabricated into other shapes, such as a triangle, a square, an oval, a moon, a star, a heart, etc.

[0057] The rod filters and hollow tubes 10, 12 can be used as filter products (in association with tobacco products) in various configurations, as shown in Figures 3-11. For example, the rod filter 10 can be used individually as a filter for a tobacco product or as part of a filter assembly (i.e., a filter including multiple components) for a tobacco product. The hollow tube 12 is generally used as part of a filter assembly for a tobacco product. In general, the hollow tube 12 is intended to function as a support element and contribute to the temperature management of the aerosol in heat-not-burn sticks and cigarettes. Nevertheless, the hollow tube 12 may contribute some degree of filtration and pressure drop. In view of the above, it should be understood that the term "filter product" as used herein encompasses individual rod filters 10, individual hollow tubes 12, and assemblies incorporating rod filters 10 and / or hollow tubes 12.

[0058] More specifically, Figures 3-7 show several configurations of a combustion cigarette. A combustion cigarette is a tobacco product that includes tobacco material that is aerosolized by burning the tobacco material to generate smoke. Figure 3 shows a combustion cigarette with tobacco material 14 (e.g., a tobacco column) at the right end and a filter product in the form of a rod filter 10 to the left of (and adjacent to) the tobacco material 14. The rod filter 10 can thus be at the tip of the cigarette, such that a user can place the rod filter 10 in the user's mouth to inhale tobacco smoke from the tobacco product. Figure 4 shows a combustion cigarette with tobacco material 14 at the right end and a filter product including an auxiliary product 16 to the left of (and adjacent to) the tobacco material 14 and a rod filter 10 to the left of (and adjacent to) the auxiliary product 16. The term auxiliary product 16 referred to herein can include various materials that may be used auxiliaryally within a tobacco product, such as activated carbon filters, flavorants / capsules, colored filters, etc. 5 shows a combustion cigarette with a filter product including tobacco material 14 at the right end, an auxiliary product 16 to the left of (and adjacent to) the tobacco material 14, an empty space 18 (e.g., hollow portion) to the left of (and adjacent to) the auxiliary product 16, and a rod filter 10 to the left of (and adjacent to) the empty space 16. FIG. 6 shows a combustion cigarette with a filter product including tobacco material 14 at the right end, a rod filter 10 to the left of (and adjacent to) the tobacco material 14, and a hollow tube 12 to the left of (and adjacent to) the rod filter 10. Thus, the hollow tube 12 can be at the tip of the cigarette, allowing a user to place the hollow tube 12 in the user's mouth and inhale tobacco smoke through the tobacco product.Finally, FIG. 7 shows a combustion cigarette with a filter product including tobacco material 14 at the right end, an auxiliary product 16 to the left of (and adjacent to) the tobacco material 14, a rod filter 10 to the left of (and adjacent to) the auxiliary product 16, and a hollow tube 12 to the left of (and adjacent to) the rod filter 10.

[0059] In addition, Figures 8-12 show multiple configurations of the heat-not-burn stick. The heat-not-burn stick is a tobacco product that includes tobacco material that is vaporized by heating the tobacco material to generate vapor with an electronic heating element. Figure 8 shows a heat-not-burn stick with a filter product that includes tobacco material 14 (e.g., tobacco column) at the right end, an empty space 18 (e.g., hollow portion) to the left of (and adjacent to) the tobacco material 14, and a rod filter 10 to the left of (and adjacent to) the empty space 18. Thus, the rod filter 10 can be at the mouth of the heat-not-burn stick, so that a user can place the rod filter 10 in the user's mouth to inhale tobacco smoke from the tobacco product. 9 is a heat-not-burn stick with a filter product including a tobacco material 14 (e.g., a tobacco column) on the right end, an auxiliary filter 20 (e.g., a polylactic acid filter) on the left side of the tobacco material 14 (and adjacent to the tobacco material 14), an empty space 18 (e.g., a hollow portion) on the left side of the auxiliary filter 20 (and adjacent to the auxiliary filter 20), and a rod filter 10 on the left side of the empty space 18 (and adjacent to the empty space 18). FIG. 10 is a heat-not-burn stick with a filter product including a tobacco material 14 (e.g., a tobacco column) on the right end, a hollow tube 12 on the left side of the tobacco material 14 (and adjacent to the tobacco material 14), an auxiliary filter 20 (e.g., a polylactic acid filter) on the left side of the hollow tube 12 (and adjacent to the hollow tube 12), and a rod filter 10 on the left side of the second filter 20 (and adjacent to the second filter 20). FIG. 11 illustrates a heat-and-burn stick with a filter product including tobacco material 14 (e.g., a tobacco column) at the right end, a first hollow tube 12 to the left of (and adjacent to) the tobacco material 14, an auxiliary product 16 to the left of (and adjacent to) the first hollow tube 12, an auxiliary filter 20 (e.g., a polylactic acid filter) to the left of (and adjacent to) the auxiliary product 16, and a second hollow tube 12 to the left of (and adjacent to) the second filter 20.Thus, the second hollow tube 12 can be at the mouth of the heat-not-burn stick, so that the user can place the second hollow tube 12 in the user's mouth to inhale tobacco smoke from the tobacco product. Finally, FIG. 12 shows a heat-not-burn stick with a filter product including a tobacco material 14 (e.g., tobacco column) at the right end, a first hollow tube 12 to the left of (and adjacent to) the tobacco material 14, a second hollow tube 12 to the left of (and adjacent to) the first hollow tube 12, and a rod filter 10 to the left of (and adjacent to) the second hollow tube 12. In particular, the first and second hollow tubes 12 of the heat-not-burn stick shown in FIG. 12 have similar (or the same) circumferences C. ext but with different inner diameters d int and / or wall thickness T wall may have the following structure:

[0060] Various configurations of filter products have been shown and described above (and in the figures). However, it should be understood that embodiments of the present invention contemplate the use of additional configurations of rod filters and hollow tubes 10, 12 (and other materials) for use in various types of consumer products, such as tobacco products. Thus, as used herein, the term tobacco products is not limited to those expressly described or shown in the figures.

[0061] The rod filters and hollow tubes 10, 12 of the present embodiments may be formed from fibers or filaments of polymeric material. "Fibers" may be either filaments or staple. Although "filaments" are referred to herein, because fibers are filaments and staple fibers are cut from filaments, any reference to filaments in the articles may be supported interchangeably with "fibers" or "staples." Thus, the articles described herein may include either single filament fibers or staple fibers, or both.

[0062] The polymeric material used for the fiber is not particularly limited.The fiber can be selected from, for example, cellulose ester, natural cellulose, regenerated cellulose and synthetic polymer.Non-limiting examples of cellulose ester include organic acid ester such as cellulose acetate (e.g., cellulose diacetate and cellulose triacetate), cellulose butyrate and cellulose propionate, inorganic acid ester such as cellulose nitrate, cellulose sulfate and cellulose phosphate, mixed acid ester such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate and cellulose nitrate acetate, and cellulose ester derivative such as polycaprolactone grafted cellulose acetate. Non-limiting examples of natural cellulose include natural cellulose obtained (prepared) from wood filaments such as wood pulp from softwoods and hardwoods, linters and other raw cotton, seed hair filaments such as bombax cotton and kapok, bast filaments typically from hemp, flax, jute, ramie, paper mulberry and paper bush, leaf filaments such as Manila hemp (abaca) and New Zealand flax. Examples of regenerated cellulose include, but are not limited to, viscose rayon, cuprammonium rayon, fortisan and nitrate rayon. Non-limiting examples of synthetic polymers include polyolefins such as polyethylene and polypropylene, polyvinyl alcohol, polyesters such as polyethylene terephthalate, and polyamides. The different materials can be used alone or in combination. The filaments are preferably selected from acrylic, modacrylic, aramid, nylon, polyester, polypropylene, rayon, polyacrylonitrile, polyethylene, PTFE or cellulose acetate. In one embodiment, the filaments comprise cellulose acetate, which includes cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose propionate butyrate, and cellulose acetate phthalate.Other polymers that can be used include starch acetate, acrylonitrile, vinyl chloride, vinyl esters, vinyl ethers, any derivatives thereof, any copolymers thereof, and any combinations thereof. Fibers from such polymeric materials can be produced by conventional techniques such as solution spinning, melt spinning, and meltblowing.

[0063] Particularly preferred embodiments of the present invention include rod filters and hollow tubes 10, 12 comprising cellulose ester fibers of cellulose acetate. One aspect of the present invention includes rod filters and hollow tubes 10, 12 each formed from cellulose ester fibers having a substantially C-shaped cross-sectional shape. Such fibers can be produced by dry or wet spinning methods, such as by extruding a cellulose ester solution through a spinneret. With reference to FIG. 13, a fiber 30 is shown having a closed "C" shaped cross-sectional configuration prepared by extruding a cellulose acetate dope or solution through the orifices of a spinneret. As used throughout, a fiber or filament exhibiting a closed C shape has a "C" shaped cross-section having a first proximal end 35 and a second proximal end 40 and a hollow core 50. More specifically, a "closed C-shaped" fiber or filament means a fiber or filament having a "C" shaped cross-section having a first proximal end and a second proximal end, and satisfying at least one of conditions A(i) or A(ii) and at least one of conditions B(i) or B(ii). A. At least a portion of the first proximal end is either: i. oriented toward at least a portion of the second proximal end; or ii. contacting a portion of the second proximal end. B. The first proximal end and the second proximal end are either: i. a gap or separation between a first proximal end and a second proximal end of the "C" shape defines a channel having a lateral distance D1, where the channel leads from an outer surface of the filament to a hollow core, the hollow core being defined by an inner surface of the filament and having a diameter D2, where D2 / D1>1; or ii. at least a portion of the first proximal end does not contact at least a portion of the opposing second proximal end thereby forming a channel.

[0064] As shown in FIG. 13, fiber 30 is in the shape of a “C” having a first proximal end 35 and a second proximal end 40, and satisfies at least one of condition A(i) or A(ii) and at least one of condition B(i) or B(ii). A. At least a portion of first proximal end 35 is either: A. i. oriented toward at least a portion of the second proximal end 40; or ii. contacting a portion of the second proximal end 40; as shown, no contact. B. First proximal end 35 and second proximal end 40 are either: i. a gap or separation between the first and second proximal ends 35, 40 of the "C" shape defines a channel having a lateral distance D1, where the channel leads from the outer surface 55a of the fiber 30 to a hollow core 50, where the hollow core 50 is defined by an inner surface 55b of the fiber and has a diameter D2, where D2 / D1>1; or ii. no channel or passage is formed resulting from at least a portion of the first proximal end 35 contacting at least a portion of the opposing second proximal end 40, as shown, in which case the proximal ends do not contact one another.

[0065] In one embodiment, or in combination with any of the preceding embodiments, the channel opens into an annulus having a diameter D2 greater than the minimum channel diameter D1. The channel distance D1 is taken as the minimum distance within the channel defined by the gap between the first proximal end 35 and the second proximal end 40 of the C-shaped fiber 30, and the diameter D2 is taken as the maximum diameter within the hollow core 50. The ratio of D2 / D1 in the same units is greater than 1:1, or at least 1.1:1, or at least 1.2:1, or at least 1.3:1, or at least 1.4:1, or at least 1.5:1, or at least 1.6:1, or at least 1.7:1, or at least 1.8:1, or at least 1.9:1, or at least 2:1, or at least 2.1:1, or at least 2.3:1, or at least 2.5:1, or at least 2.8:1, or at least 3:1, or at least 3.5:1, or at least 4:1, or at least 4.5:1, or at least 5:1, or at least 5.5:1, or at least 6:1.

[0066] With reference to FIG. 13A, the depiction and definition of the proximal end of the C-cross-sectional shape is more specifically defined. The fiber 60 includes an outer periphery 55a forming an outer arc and an inner periphery 55b forming an inner arc surrounding and forming the hollow core 50. The C-shaped filament has proximal ends 35 and 40 having imaginary planes "x" and "y" extending along the proximal ends 35 and 40, respectively. In determining whether the filament 30 is a closed C as defined herein, the orientation of the proximal ends 35 and 40 is determined. Thus, with continued reference to FIG. 13A, the orientation of the end 35 is the direction of an imaginary line (e.g., line 35a or 35b) that extends perpendicularly away from the portion of the plane x that extends along the proximal end 35. Similarly, the orientation of the end 40 is the direction of an imaginary line (e.g., line 40a or 40b) that extends perpendicularly away from the plane y of the proximal end 70.

[0067] Lines 35a or 35b can be drawn anywhere along and perpendicular to the portion of plane x extending along the proximal end 35, and fiber 60 will be in a closed C-shape if any line perpendicular to the portion of plane x extending along the proximal end 35 intersects with a portion of the opposite plane y extending along the proximal end 40, even if some lines do not intersect with a portion of the opposite plane x extending along the proximal end 40. Similarly, lines 40a or 40b can be drawn anywhere along and perpendicular to the portion of plane y extending along the proximal end 40, and fiber 60 will be in a closed C-shape if any line perpendicular to the portion of plane y extending along the proximal end 40 intersects with a portion of the opposite plane x extending along the proximal end 35, even if some lines do not intersect with a portion of the opposite plane x extending along the proximal end 35. As shown, this configuration in FIG. 13A results in a closed C-shaped fiber 60 due to the orientation of proximal end 35 toward proximal end 40, as shown by imaginary line of orientation 35a intersecting with plane y of proximal end 40, while imaginary line 35b does not intersect. Similarly, this configuration in FIG. 13A results in a closed C-shaped filament due to the orientation of proximal end 40 toward proximal end 35, as shown by imaginary line of orientation 40a intersecting with plane x of proximal end 35, while imaginary line 40b does not intersect. Any one of these conditions satisfies the requirement that at least one of the proximal ends is oriented toward the other proximal end.

[0068] First proximal end 35 and second proximal end 40 can be spaced apart by a distance of less than 1.0 radian, or less than 0.8 radians, or less than 0.5 radians, or less than 0.3 radians, or less than 0.1 radians, and still be characterized as a closed C-configuration, and in each instance can be non-contacting or at least 0.01 radians, or at least 0.05 radians, apart. In addition to the closed C-shape configurations described above in Figures 13 and 13A, it should be understood that a fiber can be considered to have a closed C-shape when one of the proximal ends (e.g., end 35 or end 40) is in contact with a portion of the other proximal end (e.g., the other of end 35 or end 40).

[0069] Conversely, Figure 13B illustrates fiber 70 that is not considered to be in a closed C-shape. In Figure 2B, the orientation of proximal end 35 is not toward proximal end 40 because an imaginary line perpendicular to and aligned with plane x of proximal end 35 cannot intersect with proximal end 40 along plane y, as shown by lines 35a or 35b. Similarly, proximal end 40 is not toward proximal end 35, as shown by imaginary orientation lines 40a and 40b not intersecting with proximal end 35 along plane x.

[0070] Referring again to FIG. 13, the core 50 of the fiber 30 is hollow, giving the fiber 30 a hollow cross section. As used herein, the term "hollow core" is not limited to a perfect circle, or a circle with a completely closed circumference. In particular, a fiber includes a "hollow core" when it includes an outer circumference (e.g., circumference 55a) and an inner circumference (e.g., circumference 55b), where the inner circumference at least partially encloses an empty interior space. For example, the hollow core can be oval, square, triangular, or other regular or irregular / distorted shape. Furthermore, the proximal ends 35 and 40 may be touching or in contact, or may be spaced apart from one another. In some embodiments, or in combination with other described embodiments, the hollow core 50 can have a diameter in a maximum dimension that is greater than the maximum distance between the proximal ends 35 and 40.

[0071] The following description illustrates a method for producing fibers (e.g., closed C fibers) that can be used in the rod filters and / or hollow tubes 10, 12. A spinning dope containing cellulose acetate and a solvent can be prepared and dry spun under conditions known to those skilled in the art. The temperature of the spinning solution can be increased and maintained by passing it through a heated candle filter. Generally, the temperature of the candle filter does not exceed the boiling point of the solvent, e.g., acetone, used in the spinning solution under the given process conditions.

[0072] In the spinneret, the solvent dope can be extruded through multiple holes to form continuous cellulose acetate fibers. The fibers can be collected to form bundles of hundreds or thousands of individual fibers. Each of these bundles or bands can contain at least 100, 150, 200, 250, 300, 350, or 400, and / or up to 1000, 900, 850, 800, 750, or 700 fibers. The spinneret can be operated at any speed suitable to produce fibers and bundles having the desired size and shape.

[0073] The spinning dope composition includes a suitable amount of cellulose acetate and a solvent. As used herein, the term "cellulose acetate tow", "acetate tow" or "acetate tow band" refers to a continuous crimped filament band comprising cellulose acetate fibers. As used herein, the term "cellulose acetate" refers to an acetate ester of cellulose in which hydrogens in the hydroxyl groups of the cellulose glucose units are replaced with acetyl groups by an acetylation reaction. The cellulose acetate has a degree of substitution in the range of 2.2 to less than 3. As used herein, the term "degree of substitution" or "DS" refers to the average number of acyl substituents per hydroglucose ring of the cellulose polymer, with a maximum degree of substitution of 3.0. In some embodiments, suitable cellulose acetate has a degree of substitution less than 3 acetyl groups per glucose unit, preferably in the range of 2.2 to 2.8, or in the range of 2.4 to 2.7, on average. In some cases, at least 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99 percent of the cellulose acetate has a DS greater than 2.2 or 2.25. In some cases, at least 90 percent of the cellulose acetate can have a DS greater than 2.2, 2.25, 2.3, or 2.35. Typically, the acetyl groups can account for at least 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 percent, and / or up to 99, 95, 90, 85, 80, 75, or 70 percent of the total acyl substituents.

[0074] The amount of cellulose acetate in the spinning dope composition can be 22wt%-32wt%, or more than 22wt%-32wt%, or more than 24wt%-32wt%, or 26-30wt% and 28-30wt%, based on the total weight of the dope solution. The amount of solvent present in the dope composition is 65wt%-78wt%, preferably 68wt%-71wt%, based on the total weight of the dope solution. The inherent viscosity of the cellulose acetate in the spinning solution can be 1.35-1.60 or 1.45-1.58.

[0075] The solids content of the spinning solution (i.e., added solids) is generally between 22 and 32 wt%. The higher the solids content, the less solvent needs to be recovered, but much above 32 weight percent, the viscosity of the spinning solution may become too high to be successfully extruded through the small spinneret holes. At solids contents below 22 weight percent, it becomes difficult to control the flow rate of the dope solution through the spinneret, excess solvent must be evaporated from the fibers, consistent fiber shape is difficult to control, and acetone recovery is high. In addition, spinning solutions with lower solids content tend to cause the fibers to adhere to the outer surface of the metal surface of the spinneret as they are spun into fibers, making it difficult to pull the filaments into a bundle or tow band.

[0076] The spinning dope solution may also contain a small amount of a matting agent such as TiO2, a small amount of water, and a small amount of a plasticizer. The dope solution according to the present invention generally has a small amount of titanium dioxide and a small amount of water added. The amount of TiO2 in the entire spinning solution is generally less than 1 wt%, or 0.5 wt% or less, or 0.3 wt% or less, or no TiO2 is added. A small amount of TiO2 can be added to increase the whiteness of the resulting filter. Too much TiO2 can clog the fine spinneret holes.

[0077] When present, the amount of the matting agent, plasticizer, and water can be 5 wt% or less each, or 5 wt% or less in total. In one embodiment, the remainder of the spin dope solution, excluding the water, matting agent, cellulose acetate, and plasticizer, is a solvent such as acetone. In one embodiment, or in combination with any of the previous embodiments, the amount of acetone is at least 60 wt%, or at least 70 wt%, or at least 80 wt%, or at least 90 wt%, or at least 95 wt%, or at least 98 wt%, or 100 wt%, based on the weight of all solvents other than water. The amount of other solvents with evaporation rate profiles different from acetone should be minimized because they will affect the shape of the fiber under the process conditions described above.

[0078] In one embodiment, or in combination with any of the previous embodiments, the spinning dope solution contains 4.5 wt% or less, or 4 wt% or less, or 3 wt% or less, or 2 wt% or less, or 1 wt% or less, or 0.5 wt% or less of plasticizer based on the total weight of cellulose acetate and plasticizer in the dope, or based on the weight of the spinning dope solution, or based on the total weight of cellulose acetate and plasticizer in the fiber, or based on the weight of the fiber, or no plasticizer is added to the solution, or no plasticizer is present in the solution. If a plasticizer is used, it can be a compound rather than a polymer and can have a molecular weight of 400 g / mole or less, or 300 g / mole or less, or 250 g / mole or less. The fibers as they exit the spinneret may or may not contain the same percentage of plasticizer, and any process for producing fibers may include dry spinning without adding plasticizer to the dope solution, or if added, within the limits described.

[0079] The amount of water present in the spinning solution of the present invention is generally less than 5 wt%, or 3 wt% or less, or 1-2 wt% or less, based on the weight of the dope solution or fiber. If the amount of water is significantly greater than 3 wt%, the drying time of the resulting fiber tends to be slow, but if the amount of water is significantly less than about 1 wt%, acetone is difficult to obtain because it is recycled from the water by distillation and the surrounding air is moist.

[0080] In certain embodiments, the fibers used in the rods and / or hollow tubes 10, 12 may be spun through "D" shaped spinneret holes. Such fibers are generally extruded in a longitudinally aligned state and can ultimately be processed into filament or staple fibers of any suitable size. For example, each fiber (filament or staple) can have a linear dpf (weight in g per 9000 m of filament length, dpf) of at least 0.5, or greater than 0.5, or at least any of 0.8, 1, 1.5, 2, 2.5, 3, 4, or 5 dpf. Additionally or alternatively, the dpf is equal to or less than any of 200, 100, 75, 50, 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4.5, 4, 3.5, 3, or 2.75 dpf. Examples of suitable dpf ranges include 0.8-30, 1.8-20, or 1-25, or 1.5-20, or 1.5-15, or 1-less than 4, or 4-30. In some particular embodiments, the fibers used in the rod filter 10 can have a dpf of 1.8-20. For example, the fibers of the rod filter 10 used in a combustible cigarette can have a dpf of 1.8-8.0 dpf, while the fibers of the rod filter 10 used in a heat-not-burn stick can have a dpf of 8.0-20.0. The fibers of the hollow tube 12 (e.g., for a heat-not-burn stick) can have a dpf of 3.4-8.0.

[0081] The fibers, including filaments and staple fibers, are desirably monofilaments. In one embodiment, the fibers comprise at least 80 wt%, or at least 90 wt%, or at least 95 wt%, or at least 97 wt%, or 100 wt% cellulose acetate polymer, based on the weight of all polymers in the fiber excluding plasticizers. In one embodiment, the fibers are not bicomponent fibers or the result of processing bicomponent fibers. The size of the individual filaments is not particularly limited. Size can be expressed as an effective diameter, and in one embodiment, the effective diameter of the filaments and staple fibers can be in the range of, for example, 0.1 μm to 1000 μm, 1 μm to 500 μm, 1 μm to 100 μm, 1 μm to 30 μm, 10 μm to 1000 μm, 10 μm to 500 μm, 10 μm to 100 μm, or 10 μm to 30 μm.

[0082] The fibers can be processed into bundles or tow bands in which multiple filaments are disposed adjacent to one another along their length and the filaments are not twisted or intertwined, or into yarns in which multiple filaments are disposed adjacent to one another along their length and the filaments are twisted or intertwined. The tow bands of fibers are often processed to effectively crimp the filaments, and depending on the end use, they can be cut into staple fibers or processed as a continuous band. As used herein, the term "staple fibers" refers to filaments cut from a filament yarn or tow band, typically having an individual length of less than 150 mm, or less than 120 mm, or 100 mm or less, or 80 mm or less, or 65 mm or less, or 60 mm or less, or 55 mm or less. In some embodiments, the staple fibers can be cut to a length of at least 1, 1.5, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17, 20, 22, 25, 27, 30, 32, or 35 mm, and no more than 130 mm, or no more than 120 mm, or no more than 100 mm, or no more than 80 mm, or no more than 65 mm. Any suitable type of cutting device can be used that can cut the filaments to the desired length without excessively damaging the fiber. Examples of cutting devices include, but are not limited to, rotary cutters, guillotines, stretch-breaking devices, reciprocating blades, and combinations thereof. Once cut, the staple fibers can be packaged or bagged or wrapped for subsequent transportation, storage, and / or use. The cut length of the staple fibers can be measured according to ASTM D-5103.

[0083] In accordance with the present invention, fiber bands (i.e., tow bands) having 5 to 500,000 individual fibers can be assembled. Alternatively, the tow bands can be assembled with 10 to 50,000, 10 to 40,000, 10 to 30,000, 10 to 20,000, 10 to 10,000, 10 to 1000, 100 to 50,000, 100 to 40,000, 100 to 30,000, 100 to 20,000, 100 to 10,000, 100 to 1000, 200 to 50,000, 200 to 40,000, 200 to 30,000, 200 to 20,000, 200 to 10,000, 200 to 1000 , 1000-50,000, 1000-40,000, 1000-30,000, 1000-20,000, 1000-10,000, 5000-50,000, 5000-40,000, 5000-30,000, 5000-20,000, 5000-10,000, 10,000-50,000, 10,000-40,000, 10,000-30,000, or 10,000-20,000 fibers of the present invention. Nevertheless, the tow band can have a total denier of 1,000 to 500,000, 2,000 to 250,000, 5,000 to 100,000, 10,000 to 75,000, 15,000 to 50,000, 20,000 to 40,000, and / or 25,000 to 30,000. In certain embodiments, the filter tow weight, i.e., the weight of the filaments only, is greater than 1.7 mg / mm, or greater than 2.0 mg / mm, or between 2.2 and 2.5 mg / mm.

[0084] The fibers processed into the tow band can then pass through a crimping zone where a patterned wavy shape is imparted to at least some, or substantially all, of the individual fibers of the tow. The crimping zone can include at least one crimping device for mechanically crimping the fibers. After crimping, the tow band can be dried in a drying zone to reduce the moisture and / or solvent content of the fibers of the tow band. The fibers in the form of the tow band can then be fed to a baler and compressed into a bale of tow fibers.

[0085] The rod filter and hollow tube 10, 12 can be formed from the tow band using a conventional automated tobacco rod making machine. Exemplary tobacco rod making machines are of the type commercially available from Molins PLC or Hauni-Werke Korber & Co. KG. For example, tobacco rod making machines of the type known as MkX (available from Molins PLC) or PROTOS (available from Hauni-Werke Korber & Co. KG) can be used. More specifically, the rod filter 10 can be formed by drawing the tow band from the bale and passing the tow band through a blooming device. Specifically, compressed air can be sprayed onto the tow band while applying a pulling force to the tow band to "bloom" the tow band and adjust the width of the tow band as needed.

[0086] After the tow band is sufficiently bloomed, it can be sprayed with a plasticizer such as triacetin. The tow band can then be compressed and processed into a cylindrical rod filter 10 in a cylindrical feed jet device. In some cases, a wrapper can be wrapped around the outer circumference of the cylindrical tow band. The cylindrical tow band (possibly including the wrapper) can then be cut into individual rod filters 10. In this manner, a plurality of rod filters 10 can be produced. The hollow tube 12 can be formed in essentially the same manner as the rod filter 12 described above, but can include a mandrel in the cylindrical feed jet device. In this manner, as the tow band is fed and compressed in the feed jet device, the tow band is formed around the mandrel to form the shape of a hollow tube.

[0087] If desired, "unwrapped" filters can also be produced. Such segments are produced using techniques of the type generally set forth herein. However, instead of using a wrapper around the longitudinal periphery of the filter material, a somewhat stiffer rod can be provided, for example, by applying steam to a molded mixed fiber bundle. Technology for commercially producing unwrapped filter rods is owned by Essentra Ltd. of Milton Keyes, UK.

[0088] Filters utilizing the fibers (e.g., closed C-shaped fibers) described herein can include one or more particulate additives, which are not particularly limited and are additives typically used in filters for smoking articles. The additives can be powder (particle size 50-150 μm) or granular (particle size 150-1000 μm). Examples of suitable particulate additives include flavoring or adsorbing agents such as menthol solutions, activated carbon / charcoal, zeolites, ion exchange resins, magnesium silicates such as sepiolite, silica gel, alumina, molecular sieves, carbonaceous polymer resins and diatomaceous earth, or combinations thereof. Other additives such as humectants or colorants can also be used. According to a particular embodiment, the particulate additive includes or is charcoal / activated carbon.

[0089] In view of the above, embodiments of the present invention include improved filter products for tobacco products. Such filter products, such as rod filters and hollow tubes 10, 12, can provide improved capabilities such as increased hardness, reduced friction, reduced pressure drop, and the like. More specifically, embodiments of the present invention can include filter products for use with tobacco products. Such filter products can be rod filters 10 or hollow tubes 12, as described above. Specifically, the filter products can include a plurality of fibers. In some embodiments, the fibers can be cellulose acetate fibers. Such fibers can include a hollow core portion. In some embodiments, the fibers can have a closed C-shaped cross section.

[0090] Embodiments can provide for such above-mentioned filter products (e.g., rod filters and / or hollow tubes 10, 12) to be included in various types of tobacco products, such as combustible cigarettes and heat-not-burn sticks. Specifically, embodiments include tobacco products (e.g., combustible cigarettes and / or heat-not-burn sticks) that include tobacco and filter products, where the filter products include a plurality of cellulose acetate fibers having a hollow core portion. In some embodiments, the fibers can include fibers having a closed C-shaped cross section.

[0091] To increase stiffness, individual fibers included in the filter product can have improved moment of inertia values ​​compared to fibers in previously manufactured filter products. Such improved moment of inertia values ​​can be obtained by fibers with hollow cross sections, such as fibers with closed C-section shapes. More specifically, the moment of inertia of a fiber reflects how the area of ​​the fiber's cross section is distributed relative to a particular axis. The more mass of the fiber that is away from the axis, the greater the moment of inertia. The greater the moment of inertia, the greater the resistance to bending of the cross section. In other words, the greater the moment of inertia of a given fiber, the greater the stiffness of the fiber. Because fibers with hollow cross sections, such as closed C-fibers, have much of their constituent material located away from the longitudinal axis (such as the bending axis of the fiber), they have a significantly increased moment of inertia, and therefore improved bending stiffness or rigidity, compared to solid cross section fibers (such as fibers with Y-shaped or circular cross sections).

[0092] In view of the above, an embodiment of the present invention provides a filter product according to the present invention, the fibers within which the filter product according to the present invention is, on average, at least 50,000 μm 4 , at least 60,000 μm 4 , at least 70,000 μm 4 , at least 75,000 μm 4 , at least 80,000 μm 4 , at least 90,000 μm 4 , 100,000μm 4 , at least 110,000 μm 4, at least 120,000 μm 4 , at least 130,000 μm 4 , or at least 135,000 μm 4 , or at least 140,000 μm 4 , and / or 50,000 μm 4 ~140,000μm 4 , 60,000μm 4 ~140,000μm 4 , 70,000μm 4 ~140,000μm 4 , 80,000μm 4 ~140,000μm 4 , 90,000μm 4 ~140,000μm 4 , 100,000μm 4 ~140,000μm 4 , 110,000μm 4 ~140,000μm 4 , 120,000μm 4 ~140,000μm 4 , 130,000μm 4 ~140,000μm 4 , 50,000μm 4 ~100,000μm 4 , 60,000μm 4 ~100,000μm 4 , 70,000μm 4 ~100,000μm 4 , 80,000μm 4 ~100,000μm 4 , 90,000μm 4 ~100,000μm 4 , 80,000μm 4 ~120,000μm 4 , 90,000μm 4 ~120,000μm 4 , 100,000μm 4 ~120,000μm 4 , or 110,000 μm 4 ~120,000μm 4In certain embodiments, one or more fibers included in each of the filter products of the present invention have an area moment of inertia of at least 75,000 μm 4 , at least 80,000 μm 4 , at least 90,000 μm 4 , at least 100,000 μm 4 , at least 110,000 μm 4 , at least 120,000 μm 4 , at least 130,000 μm 4 , at least 135,000 μm 4 , at least 140,000 μm 4 , or at least 145,000 μm 4 It can have a maximum area moment of inertia of .

[0093] For a given fiber, the area moment of inertia value can be obtained by first determining the principal moments of inertia at the center of gravity of the cross-sectional area of ​​the fiber (i.e., "lx" and "ly" shown for fiber 30 shown in FIG. 14). The following formula can then be applied:

number

[0094] To reduce friction, the fibers included in the filter product can have improved coefficient of friction values ​​over fibers of previously manufactured filter products. Such improved coefficient of friction values ​​can be obtained by fibers having a generally round or circular outer surface (e.g., outer surface 55b), such as in the case of fibers having a closed C-shaped cross-section shape. More specifically, the round or circular outer surface reduces the contact area, especially for fibers having a Y-shaped cross-section, and reduces friction between other fibers and / or other materials, such as metal parts (e.g., mandrels) of a filter making machine. In any case, embodiments provide for the fibers in the filter products of the present invention to have a fiber-to-fiber coefficient of friction value of 0.150 or less, 0.145 or less, 0.140 or less, 0.135 or less, 0.130 or less, or 0.129 or less, or 0.125 or less, and / or between 0.125 and 0.150, 0.130 and 0.145, 0.130 and 0.140, or 0.130 and 0.135. Embodiments provide for the fibers in the filter products of the present invention to have a fiber-to-metal coefficient of friction value of 0.568 or less, 0.565 or less, 0.560 or less, 0.555 or less, 0.550 or less, 0.545 or less, 0.542 or less, or 0.540 or less, and / or between 0.540 and 0.560, between 0.540 and 0.555, between 0.540 and 0.540, or between 0.540 and 0.545.

[0095] This reduced coefficient of friction value indicates that cellulose acetate tow made from filaments having a closed C-shaped cross section can be processed faster than tows made from filaments having other cross-sectional shapes (e.g., round / circular and / or Y-shaped cross-sections). Specifically, it has been found that cellulose acetate tows formed from filaments having a closed C-shaped cross section can be processed into filter products about 30% faster than cellulose acetate tows formed from filaments having a Y-shaped cross section and about 13% faster than cellulose acetate tows formed from filaments having a round / circular cross section.

[0096] In some embodiments, the filter products of the present invention can include cylindrical rods, such as rod filter 10, which have a generally solid cross-section. The cylindrical rod filters are formed from a plurality of fibers (e.g., cellulose acetate fibers), which include a hollow core portion. Thus, the fibers can have a closed C-shaped cross-section. In any case, the cylindrical rod filters can have a mass of 560 mg or less and a hardness of at least 83.0%. Such hardness values ​​are determined using a Borgwaldt testing device with a mass of 3 Kg, as described in more detail in the Examples section below. In certain embodiments, a cylindrical rod filter having a mass of 560 mg or less can have a hardness of at least 82.8%, at least 82.9%, at least 83.1%, at least 83.2%, at least 83.3%, at least 83.4%, at least 83.5%, at least 83.6%, at least 83.7%, at least 83.8%, at least 83.9%, or at least 84.0% and / or 82.8-84.0%, 82.9-83.8%, or 83.0-83.6%. Further, in some embodiments, the cylindrical rod filter can have a hardness value of at least 83.0%, and the mass of cellulose acetate in the rod filter can be 555 mg or less, 550 mg or less, 545 mg or less, 540 mg or less, 535 mg or less, 530 mg or less, 525 mg or less, or 520 mg or less, and / or 520 to 560 mg, 530 to 560 mg, 540 to 560 mg, and / or 550 to 560 mg.

[0097] In a further specific embodiment, the cellulose acetate in the cylindrical rod filter of the present invention can have a mass of 540 mg or less, and the rod filter has a hardness of at least 83.5%, at least 83.6%, at least 83.7%, at least 83.8%, at least 83.9%, or at least 84.0%, and / or 83.5-84.0%, 83.6-83.9%, or 83.7-83.8%. In yet another embodiment, the cellulose acetate in the cylindrical rod filter of the present invention can have a mass of 580 mg or less, and the rod filter has a hardness of at least 84.5%, at least 84.6%, at least 84.7%, at least 84.8%, at least 84.9%, or at least 85.0%, and / or 84.5-85.0%, 84.6-84.9%, or 84.7-84.8%.

[0098] In some embodiments, the cylindrical rod filter has an outer diameter d ext In such an embodiment, the normal size cylindrical rod filter may have a hardness value of 81.0 to 84.0%. In another embodiment, the normal size cylindrical rod filter may have an outer diameter d ext In such an embodiment, the slim size cylindrical rod filter may have a hardness value of 75.0 to 82.0%. In a further embodiment, the cylindrical rod filter may have an outer diameter d ext In such an embodiment, the slim size cylindrical rod filter may have a hardness value of 72.0 to 77.0%.

[0099] In some embodiments, the filter product of the present invention may include a cylindrical rod, such as rod filter 10, which has a generally solid cross section. The cylindrical rod filter is formed from a plurality of fibers (e.g., cellulose acetate fibers), which include a hollow core portion. Thus, the fibers may have a closed C-shaped cross section. In any event, in some particular embodiments, the cylindrical rod filter may have a mass of 520-600 mg of cellulose acetate. Furthermore, when such particular cylindrical rod filter is used in a tobacco product, such cylindrical rod filter may be configured to experience a pressure drop of 115 mmWG or less. In certain embodiments, a cylindrical rod filter having a mass of 520-600 mg of cellulose acetate may be configured to experience a pressure drop of 110 mmWG or less, or 105 mmWG or less, and / or 105-115 mmWG, 105-110 mmWG, or 110-115 mmWG. Further, in some embodiments, the cylindrical rod filter can experience a pressure drop of 115 mmWG or less when the mass of cellulose acetate in the filter is between 530 and 590 mg, between 540 and 580 mg, between 550 and 570 mg, and / or about 560 mg.

[0100] In additional embodiments, the filter product of the present invention can include hollow cylindrical tubes, such as hollow tube 12, each of which has an inner diameter and an outer diameter that presents a hollow cross section. The hollow tubes are formed from a plurality of fibers (e.g., cellulose acetate fibers), the fibers including a hollow core portion. Thus, the fibers can have a closed C-shaped cross section. In any event, the cylindrical hollow tubes have a mass of 495 mg or less and a hardness of at least 92.0%. Such hardness values ​​are determined using a Borgwaldt testing device with a mass of 3 Kg, as described in more detail in the Examples section below. In certain embodiments, cylindrical hollow tubes having a mass of 495 mg or less can have a hardness of at least 92.1%, at least 92.2%, at least 92.3%, at least 92.4%, or at least 92.5%, and / or 92.0-92.5%, 92.1-92.4%, or 92.2-92.3%. Further, in some embodiments, the cylindrical hollow tube can have a hardness value of at least 92.0% and a mass of cellulose acetate in the hollow tube is 492 mg or less, 490 mg or less, 487 mg or less, 485 mg or less, 483 mg or less, or 481 mg or less, and / or 481-495 mg, 481-490 mg, 481-487 mg, and / or 481-485 mg. In some additional embodiments, the cylindrical hollow tube has a hardness value of at least 92.0%, at least 92.1%, at least 92.2%, at least 92.3%, at least 92.4%, or at least 92.5% and a mass of 497 mg or less.

[0101] In some embodiments, hollow tubes can have hardness values ​​as described above in various sizes. For example, in some embodiments, a hollow tube (having a mass of 495 mg or less and a hardness of at least 92.0%) has an outer diameter d ext In some embodiments, the hollow tube (having a mass of 495 mg or less and a hardness of at least 92.0%) has a wall thickness T wall (The outer diameter of eachext From inner diameter d int The distance from the tip to the tip (distance from the tip to the tip) can be 0.6 to 1.4 mm, 0.8 to 1.2 mm, or about 1.0 mm. EXAMPLES

[0102] Example 1 A plurality of cellulose acetate filaments having a dpf of about 6.7 were formed. Such filaments were formed by extruding a cellulose acetate dope solution through a spinneret orifice as previously described. The resulting filaments were processed into crimped tow bands containing 10-15 fibers. A first sample of cellulose acetate filaments, EX1-C, was cast into epoxy resin under tension and cut / polished to expose the cross-sectional area of ​​the filament. The filaments of the EX1-C sample had a closed C-shaped cross-section. A second sample of cellulose acetate filaments, EX1-R, was cast into epoxy resin under tension and cut / polished to expose the cross-sectional area of ​​the filament. The filaments of the EX1-R sample had a solid round / circular cross-section.

[0103] To determine the moment of inertia of the filaments, the EX1-C and EX1-R samples were photographed under an optical microscope with high contrast. The images were imported into Solidworks software, and the cross-sectional shape of the filaments was outlined. The software then calculated the cross-sectional area of ​​each filament and the principal moments of inertia (i.e., lx and ly) of each region at the center of gravity of the filament. The moment of inertia of the resulting filaments was determined based on the algorithm described above. The filaments of the EX1-C group, which have a hollow closed C-shaped cross section, had an average moment of inertia value of 74,297 μm 4 and at least one filament has a maximum moment of inertia value of 141,566 μm 4 In contrast, the filaments of the EX1-R group, which have a solid round / circular cross section, had an average moment of inertia value of 49,754 μm 4and at least one filament has a maximum moment of inertia value of 74,323 μm 4 Thus, the filaments having a closed C-shaped cross section had significantly higher moment of inertia values ​​than the filaments having a round / circular cross section. The moment of inertia value is generally understood to be an indication of the ability of a filament to resist bending or flexing. In particular, the higher the moment of inertia, the stiffer or stiffer the filament. Thus, the filaments having a closed C-shaped cross section were determined to be significantly stiffer (less likely to bend) than the filaments having a round / circular cross section. Such increased stiffness can be beneficial in the construction of filters to produce filters having a preferred level of stiffness, as described further below.

[0104] Example 2 Ten bobbins of multifilament yarn were produced at zero twist level. More specifically, a first yarn of cellulose acetate filaments, EX2-C, was formed, such filaments had a closed C-shaped cross section. A second yarn of cellulose acetate filaments, EX2-R, was formed, such filaments had a solid round / circular cross section. A third yarn of cellulose acetate filaments, EX2-Y, was formed, such filaments had a solid Y-shaped cross section. All yarns were formed with the same composition (i.e., cellulose acetate filament composition, lubricant content, denier, and entanglement). The yarn-to-yarn friction coefficient and yarn-to-metal pin friction coefficient were measured with a Lawson-Hemphill CTTE friction test device. The yarn-to-yarn measurements were performed according to ASTM D3412, Standard Test Method for Yarn-to-Yarn Friction Coefficient, and the yarn-to-metal measurements were performed according to ASTM D3108, Standard Test Method for Yarn-to-Solid Material Friction Coefficient.

[0105] The EX2-C yarn formed from filaments having a closed C-shaped cross section was found to have a fiber-to-metal coefficient of friction of 0.542 and a fiber-to-fiber coefficient of friction of 0.129. The EX2-R yarn formed from filaments having a solid round / circular cross section had a fiber-to-metal coefficient of friction of 0.419 and a fiber-to-fiber coefficient of friction of 0.136. The EX2-Y yarn formed from filaments having a solid Y-shaped cross section had a fiber-to-metal coefficient of friction of 0.569 and a fiber-to-fiber coefficient of friction of 0.152. Thus, the EX2-C yarn was shown to have (i) a lower fiber-to-metal coefficient of friction value than the EX2-Y yarn and (ii) a lower fiber-to-fiber coefficient of friction value than both the EX2-R and EX2-Y yarns. This reduced coefficient of friction value indicates that cellulose acetate tow made from filaments having a closed C-shaped cross-section can be processed (e.g., to form filter products for tobacco products) at higher speeds than tow made from filaments of other cross-sectional shapes (e.g., round / circular and / or Y-shaped cross-section filaments).

[0106] Example 3 A Hauni KDF-AF4 filter manufacturing device was used to make three sets of 30 filters, EX3-C, EX3-R and EX3-C. Each filter included a solid cylindrical rod filter, such as rod filter 10 described above in the detailed description. The filters were made from cellulose acetate tow having a total denier of about 26,800, with the filaments of the tow having a dpf of about 6.7. Each filter was made to a length of 120 mm, a circumference of 24.4 mm and a plug wrap thickness of 0.037 mm. The first filter set, EX3-C, was made from cellulose acetate tow containing filaments with a closed C-shaped cross section. The second filter set, EX3-R, was made from cellulose acetate tow containing filaments with a solid round / circular cross section. The third filter set, EX3-Y, was made from cellulose acetate tow containing filaments with a Y-shaped cross section. The three sets of filters were tested using the Coresta standard method for determining the pressure drop capacity curve of the filter. Such a capacity curve comprises a bivariate plot showing pressure drop values ​​for a given filter weight.

[0107] To obtain the pressure drop capacity curves, filters in each set were manufactured with the maximum possible tow mass / weight (i.e., maximum capacity) and the minimum possible mass / weight (minimum capacity). The maximum capacity point was defined as the point at which the plug maker's garniture would not accept additional tow. Any attempt to increase the tow mass / weight beyond this point would result in roll wrap, failure of the rod seam seal, or excessive variation in filter characteristics. The minimum capacity point was defined as feeding the garniture with the minimum possible tow mass / weight while still maintaining an acceptable filter in terms of no wrinkles and very slight end recession (approximately 1.0 mm). Filters of intermediate mass / weight (halfway between the minimum and maximum) were also manufactured. Filters manufactured at these three conditions (maximum, minimum, intermediate mass / weight) were tested for pressure drop as described above and a curve was plotted through the measured pressure drop values ​​to generate the pressure drop capacity curve. This curve is plotted graphically in Figure 15.

[0108] As shown, filters containing closed C-shaped filaments (i.e., EX3-C) exhibited significantly reduced pressure drop when compared to filters containing round / circular filaments (i.e., EX3-R) or Y-shaped filaments (i.e., EX3-Y). For example, a filter containing closed C-shaped filaments (i.e., EX3-C) with a mass of 560 mg exhibited a pressure drop of 105 mmWG. In contrast, a filter containing Y-shaped filaments (i.e., EX3-Y) exhibited a significantly higher pressure drop of 150 mmWG. It is noted that the pressure drop value of the filter containing round / circular filaments (i.e., EX3-R) was not achieved at a mass / weight as low as 560 mg. Thus, it was shown that filters containing closed C-shaped filaments (i.e., EX3-C) can achieve favorably low pressure drop values ​​across the mass / weight range when compared to filters containing different shaped filaments such as Y-shaped filaments (i.e., EX3-Y) and round / circular filaments (i.e., EX3-R).

[0109] Additionally, groups of 10 filter rods from each of the three sets of filters, EX3-C, EX3-R, and EX3-C, were tested using a Borgwaldt H37 testing device to determine the filter hardness values. Specifically, a 3 Kg load was applied to each filter to compress the filter. The load was then released. The original and final outer diameters d ext Measure the final outer diameter and the original outer diameter d ext The hardness value for each filter was determined as a ratio of hardness to filter weight. To obtain a filter hardness capacity curve, hardness values ​​for the three filter conditions (maximum, minimum and intermediate mass / weight) were obtained as described above. A curve was plotted through the measured hardness values ​​to generate a hardness capacity curve, which is plotted graphically in FIG. 16. Such a capacity curve comprises a bivariate plot showing hardness values ​​for a given filter weight.

[0110] As shown, filters containing closed C-shaped filaments (i.e., EX3-C) exhibited increased stiffness across a significant portion of the filter mass range when compared to filters containing round / circular filaments (i.e., EX3-R) or Y-shaped filaments (i.e., EX3-Y). For example, at a mass of 560 mg, filters containing closed C-shaped filaments (i.e., EX3-C) exhibited a stiffness value of 84%. In contrast, filters containing Y-shaped filaments (i.e., EX3-Y) exhibited a significantly lower stiffness value of 82.7. It is noted that the stiffness value of the filters containing round / circular filaments (i.e., EX3-R) was not achievable at a mass / weight as low as 560 mg. Thus, it was shown that filters containing closed C-shaped filaments (i.e., EX3-C) can achieve acceptable hardness values ​​using less tow than filters containing filaments of different shapes (e.g., Y-shaped filaments (i.e., EX3-Y) and round / circular filaments (i.e., EX3-R)).

[0111] Example 4 Hauni NWT KDF-2ER and NWT KDF-M filter manufacturing devices were used to form three sets of ten filter products, EX4-C, EX4-R and EX4-C. Each filter product included a hollow cylindrical hollow tube, such as hollow tube 12 described above in the detailed description. The hollow tubes were made from cellulose acetate tow having a total denier of about 26,800, and the hollow tubes had a dpf of about 6.7. Each hollow tube had a length of 96.1 mm and an outer diameter d ext 7.1mm, wall thickness T wall The tubes were formed with a diameter of 1.05 mm and a triacetin content of 100 mg. The first set of hollow tubes, EX4-C, were formed from cellulose acetate tow containing filaments with a closed C-shaped cross section. The second set of hollow tubes, EX4-R, were formed from cellulose acetate tow containing filaments with a solid round / circular cross section. The third set of hollow tubes, EX4-Y, were formed from cellulose acetate tow containing filaments with a solid Y-shaped cross section.

[0112] Three sets of filter products EX4-C, EX4-R and EX4-C were tested using a Borgwaldt H37 testing device to determine the hardness value of the hollow tubes. Specifically, a load of 3Kg was applied to each hollow tube to compress the tubes. The load was then released. The original and final outer diameters d ext Measure the final outer diameter and the original outer diameter d ext The hardness value for each hollow tube was determined as the ratio of hardness to mass / weight. To obtain a hollow tube hardness capacity curve, hardness values ​​were obtained for the three filter conditions (maximum, minimum and intermediate mass / weight) described above in Example 3. A curve was plotted through the measured hardness values ​​to generate a hardness capacity curve. This curve is plotted graphically in FIG. 17. Such a capacity curve comprises a bivariate plot showing hardness values ​​for a given hollow tube weight.

[0113] As shown, hollow tubes containing closed C-shaped filaments (i.e., EX4-C) exhibited increased hardness across the entire mass / weight range when compared to hollow tubes containing round / circular filaments (i.e., EX4-R) or Y-shaped filaments (i.e., EX4-Y). For example, it is understood that a hardness value of 92% is generally considered a standard hardness value for hollow cylindrical hollow tubes. The hollow tube containing closed C-shaped filaments (i.e., EX4-C) was shown to achieve such a hardness value of 92% with a mass of only 481 mg. In contrast, the hollow tube containing Y-shaped filaments (i.e., EX4-Y) was not able to achieve a hardness value of 92% until it reached a mass / weight of 497 mg. Similarly, the hollow tube containing round / circular filaments (i.e., EX4-R) was not able to achieve a hardness value of 92% until it reached a mass / weight of 520 mg. Thus, it has been shown that hollow tubes containing closed C-shaped filaments (i.e., EX4-C) can achieve acceptable hardness values ​​using less tow material than hollow tubes containing different shaped filaments, such as Y-shaped filaments (i.e., EX4-Y) and round / circular filaments (i.e., EX4-R).

[0114] Although the present invention has been disclosed in conjunction with the description of certain embodiments, including those currently believed to be preferred embodiments, the detailed description is intended to be illustrative and should not be understood as limiting the scope of the disclosure. As will be appreciated by those skilled in the art, the present invention includes embodiments other than those specifically described herein. Modifications and variations of the described embodiments may be made without departing from the spirit and scope of the present invention.

[0115] Furthermore, it is understood that any range, value, or property recited for any single component of this disclosure can be used interchangeably with any range, value, or property recited for any other component of this disclosure, where compatible, to form embodiments having the stated values ​​for each component, as set forth throughout this specification. For example, polymer layers containing any of the recited ranges for residual hydroxyl content, as well as any of the recited ranges for plasticizer content, can be suitably formed to form many unrecited combinations within the scope of the present invention.

Claims

1. 1. A filter product for use in a consumer product, said filter product comprising: comprising a plurality of cellulose acetate fibers; the fiber comprises a hollow core portion; The fibers have an average diameter of at least 50,000 μm ４ A filter product having an area moment of inertia of

2. 2. The filter product of claim 1, wherein the cellulose acetate has a degree of substitution (DS) of 2.2 to 2.

8.

3. 3. The filter product of claim 1 or 2, wherein each of said fibers has a closed C-shaped cross-section.

4. A fiber has a closed C-shaped cross-section if the cross-section exhibits a proximal first end and a proximal second end and satisfies at least one of conditions A(i) or A(ii) and at least one of conditions B(i) or B(ii): A. At least a portion of the first proximal end comprises: i. oriented toward at least a portion of the second proximal end; or ii. contacting a portion of the second proximal end; and B. the first proximal end and the second proximal end i. forming a channel defined by a gap or separation between a first proximal end and a second proximal end of a "C" shape, the channel having a lateral distance D1, the channel leading from an outer surface of the filament to a hollow core, the hollow core being defined by an inner surface of the filament and having a diameter D2, where D2 / D1>1; or ii. at least a portion of the first proximal end does not contact at least a portion of the opposing second proximal end to form a channel; 4. The filter product according to claim 3, wherein

5. The filter product of any one of claims 1 to 4, wherein the consumer product is a tobacco product.

6. 6. The filter product of claim 5, wherein the tobacco product is a combustible cigarette.

7. 7. The filter product of claim 6, wherein each of said fibers has a denier per filament (dpf) of 1.8 to 20.

0.

8. 8. The filter product of claim 7, wherein said filter product is formed from a tow of fibers, said tow having a total denier of 20,000 to 40,000.

9. 6. The filter product of claim 5, wherein the tobacco product is a heat-not-burn stick.

10. 10. The filter product of claim 9, wherein each of said fibers has a denier per filament (dpf) of 8.0 to 20.

0.

11. 10. The filter product of claim 9, wherein each of said fibers has a denier per filament (dpf) of 3.4 to 8.

0.

12. 10. The filter product of claim 9, wherein the filter product is formed from a tow of fibers, the tow having a total denier of 20,000 to 40,000.

13. The filter product of any one of claims 1 to 6 or 9, wherein the filter product comprises a cylindrical rod having a solid cross section.

14. The filter product of any one of claims 1 to 6 or 9, wherein the filter product comprises a cylindrical tube having an inner diameter and an outer diameter defining a hollow cross section.

15. The filter product of any one of claims 1 to 6, 9, 13 or 14, further comprising a plasticizer.

16. 16. The filter product of claim 15, wherein the plasticizer is triacetin.

17. The fibers have an average area moment of inertia of at least 60,000 μm ４ , at least 70,000 μm ４ , and / or at least 75,000 μm ４ or having a fiber-to-metal coefficient of friction of 0.565 or less; or a fiber-to-fiber coefficient of friction of 0.135 or less.

18. The filter product of any one of claims 1 to 4, wherein the consumer product is a botanical product.

19. 1. A filter product for use in a consumer ingredient, said filter product comprising: comprising a plurality of cellulose acetate fibers; the fiber comprises a hollow core portion; The fibers have a fiber-to-metal coefficient of friction of 0.565 or less.

20. 1. Consumer products, including tobacco and filter products, comprising: The filter product comprises a plurality of cellulose acetate fibers having a hollow core portion, and the consumer product is a heat-not-burn stick or a combustible cigarette.

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