FIRM FILTER FOR AEROSOL-GENERATING ARTICLE

Abstract

An aerosol-generating article (10) includes an aerosol forming substrate (20) and a filter (30) downstream of the substrate. The filter comprises filter material comprising filaments having a linear density of about 4 denier or greater. The filter has a resistance to draw of less than 130 mmWG. Preferably, the filter has a resistance to draw of 90 mmWG or less. More preferably, the filter has a resistance to draw of 70 mmWG or less. Preferably, the density of the filter material is about 0.12 g/cm.sup.3 or greater.

Claims

1. An aerosol-generating article, comprising: an aerosol forming substrate; and a filter downstream of the aerosol forming substrate, wherein the filter comprises filter material comprising cellulose acetate filaments having a linear density of about 6 denier or greater and a density of 0.19 g/cm.sup.3 or less, wherein the filter has a resistance to draw of less than 130 mmWG.

2. The aerosol-generating article according to claim 1, wherein the filter has a resistance to draw of 90 mmWG or less.

3. The aerosol-generating article according to claim 1, wherein the filter has a resistance to draw of 70 mmWG or less.

4. The aerosol-generating article according to claim 1, wherein the density of the filter material is about 0.12 g/cm.sup.3 or greater.

5. The aerosol-generating article according to claim 1, wherein the density of the filter material is from about 0.12 g/cm.sup.3 to about 0.15 g/cm.sup.3.

6. The aerosol-generating article according to claim 1, wherein the filaments have a linear density of 7 denier or greater.

7. The aerosol-generating article according to claim 1, wherein the filaments have a linear density of about 8 denier.

8. The aerosol-generating article according to claim 1, wherein the filter material further comprising a plasticizer.

9. The aerosol-generating article according to claim 1 wherein the filter comprises a plug wrap disposed about the filter material.

10. The aerosol-generating article according to claim 9, wherein the filter further comprises a hardness enhancing coating on the plug wrap.

11. The aerosol-generating article according to claim 10, wherein the coating comprises polyvinyl alcohol.

12. The aerosol-generating article according to claim 1, wherein the aerosol-generating substrate comprises tobacco.

Description

[0059] Referring now to the drawings, in which some aspects of the present invention are illustrated. It will be understood that other aspects not depicted in the drawings fall within the scope and spirit of the present invention. The schematic drawings are not necessarily to scale. Like numbers used in the figures refer to like components, steps and the like. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labelled with the same number. In addition, the use of different numbers to refer to components in different figures is not intended to indicate that the different numbered components cannot be the same or similar to other numbered components.

[0060] FIG. 1 is a schematic perspective view of an embodiment of a partially unrolled aerosol-generating article 10 having a filter 30. The aerosol-generating article 10, a cigarette in the depicted embodiment, is depicted as partially unrolled merely to illustrate representative components of the article. The aerosol-generating article 10 includes a rod of aerosol-forming substrate 20, such as a tobacco rod, and a filter 30 downstream of the aerosol-forming substrate 20. The filter 30 and the rod 20 are coaxially aligned with the longitudinal axis of the aerosol-generating article 10, which axis is depicted by line A-A. The depicted aerosol-generating article 10 includes a plug wrap 60, cigarette paper 40, and tipping paper 50. The cigarette paper 40 circumscribes at least a portion of the rod 20. Tipping paper 50 or other suitable wrapper circumscribes the plug wrap 60 and a portion of the cigarette paper 40 as is generally known in the art. The filter 30 includes the plug wrap 60 and filter material 32.

[0061] The exemplary embodiments described above are not limiting. Other embodiments consistent with the exemplary embodiments described above will be apparent to those skilled in the art.

[0062] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein.

[0063] As used herein, the singular forms a, an, and the encompass embodiments having plural referents, unless the content clearly dictates otherwise.

[0064] As used herein, or is generally employed in its sense including and/or unless the content clearly dictates otherwise. The term and/or means one or all of the listed elements or a combination of any two or more of the listed elements.

[0065] As used herein, have, having, include, including, comprise, comprising or the like are used in their open-ended sense, and generally mean including, but not limited to. It will be understood that consisting essentially of, consisting of, and the like are subsumed in comprising, and the like.

[0066] The words preferred and preferably refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, including the claims.

EXAMPLES

[0067] Presented below is a non-limiting example illustrating selection of filter material weight, plasticizer weight percent, and filament linear density, and plug wrap properties that resulted in enhanced filter hardness. Nineteen filters were made with cellulose acetate tow (y-shaped fibers) having different filament linear densities and different amount of plasticizer (triacetin). The resulting filter material was wrapped with plug wraps having different weight bases and thicknesses. The resulting filters had a diameter of 7.71 mm and a length of 126 mm. The materials used in making some of the nineteen filters are presented below in Table 1.

TABLE-US-00001 TABLE 1 Components of tested filters Sample Number 1 2 4 5 12 13 15 Triacetin % 7 7 7 10 7 10 10 Linear wt 3 3.4 3.4 3.4 8 8 8 of filament (denier) Thickness 148 148 100 100 100 100 100 of paper Weight basis 61 61 78 78 78 78 78 of paper

[0068] The average radial hardness of the 126 mm long filter rods was determined as described in U.S. Published Patent Application Publication Number 2016/0128378. The RTD of the 126 mm long filter rods was measured according to ISO Standard 6565:2002. The stiffness of the plug wrap was measured according to ISO 2493-1:2010 and ISO 2493-2:2011. For some filters, the weight of the filter material and plasticizer was determined, as well as the density of the weighed material (based on the diameter of 7.71 mm). The results are presented in Table 2 below.

TABLE-US-00002 TABLE 2 Properties of filters Sample Number 1 2 4 5 12 13 15 Tow + plasticizer weight (mg) 706.2 728.1 Density (g/cm3) 0.119 0.123 paper stiffness - MD - 15 10 135 135 323 323 323 323 323 mm (mN .Math. mm) paper stiffness - CD - 15 10 75 75 165 165 165 165 165 mm (mN .Math. mm) Radial hardness percent 92.200 94.650 95.413 95.827 95.963 96.460 97.373 RTD (mmWG) 340 330 360 369 206 206 255 (100 hardness) RTD 2652 1765.5 1651.3 1539.8 831.6 729.2 669.9 [(100 hardness) RTD]/mm 21.0 14.0 13.1 12.2 6.6 5.8 5.3

[0069] As shown in Table 1 and Table 2, increasing the basis weight and thickness of the plug wrap tended to increase the stiffness of the plug wrap and hardness of the filter. Increasing the linear density of the filament tended to increase radial hardness. Increasing the weight percent of plasticizer also tended to increase the radial hardness.

[0070] To observe the effect of increasing the linear density on increased average radial hardness, compare, for example, sample number 1 to sample number 2, and sample numbers 4 and 5 to sample numbers 12 and 13, respectively.

[0071] Increasing the linear density of the filament and the weight percent of plasticizer tended to increase the weight and density of the filter, which correlated directly with radial hardness.

[0072] Note that the RTD is tested on filter rods having a length of 126 mm, which may be longer than those that may be used in some aerosol-generating articles. For purposes of illustration, filter 15 had an RTD of 255 mmWG, which is an RTD per mm of about 2.02, which would be expected to result in a RTD of about 42.5 mmWG for a filter having a length of 21 mm. Thus, a 21 mm long filter for filter 15 would be expected to have an average radial hardness of 97.607% (as length should not substantially affect radial hardness), while having a low RTD of about 42.5 mmWG.

[0073] A filter having such a high hardness and such low RTD is particularly desirable.

[0074] Thus, methods, systems, apparatuses, assemblies and articles for filters having enhanced hardness are described. Various modifications and variations of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are apparent to those skilled in the mechanical arts, chemical arts, and aerosol-generating article manufacturing or related fields are intended to be within the scope of the following claims.