WO2025141095A1

WO2025141095A1 - Filter comprising a fibrous substrate comprising a base web comprising perforated through-holes

Info

Publication number: WO2025141095A1
Application number: PCT/EP2024/088476
Authority: WO
Inventors: Thomas BLIN; Patrick Guilchet
Original assignee: Swm Holdco Luxembourg
Current assignee: Swm Holdco Luxembourg
Priority date: 2023-12-26
Filing date: 2024-12-24
Publication date: 2025-07-03
Anticipated expiration: 2026-06-26

Abstract

The present invention relates to a filter comprising a fibrous substrate as a filter media comprising a base web comprising perforated through-holes, said filter having satisfactory nicotine retention capacity.

Description

Title: FILTER COMPRISING A FIBROUS SUBSTRATE COMPRISING A BASE WEB COMPRISING PERFORATED THROUGH-HOLES

Technical Field

[0001] The invention relates to the filter comprising a fibrous substrate as filter media, in particular the filter for a smoking or vaping article.

Background Art

[0002] A filter for a smoking or vaping article has a right circular cylindrical shape and generally comprises an outer envelope of plug wrap paper and a filter media located within the outer envelope. The filter for a smoking or vaping article, by virtue of the substrate, makes it possible to prevent the user from inhaling tobacco particles and allows retention of the harmful particulate substances contained in the smoke or the aerosol.

[0003] Conventional filters comprise cellulose acetate tow. Said conventional filters are also known as cellulose acetate filters. The cellulose acetate filters have a nicotine retention capacity such that the user's perception of the filtered smoke is satisfactory. However, the cellulose acetate filters degrade very slowly and have negative impact on the environment. Indeed, the filter is not consumed during the smoking/vaping of a smoking/vaping article and is regularly found in the environment. Cellulose acetate filters thus have a significant environmental impact.

[0004] To limit the environmental impact of cellulose acetate filters, it has been proposed to replace the cellulose acetate tow with a paper substrate. As the paper substrates are biodegradable, the filters comprising a paper substrate degrade rapidly. However, the filters comprising a paper substrate have higher filtration efficiency, in particular higher nicotine retention capacity than cellulose acetate filters. Since the nicotine retention capacity is higher, then the perception of the filtered smoke by the user may not be satisfactory. Accordingly, the user experience provided by the filters comprising a paper substrate is not as satisfactory as the user experience provided by the cellulose acetate filters.

Technical problem

[0005] There is therefore a need for a fibrous substrate which can be used as a filter media and enables the manufacture of a filter for a smoking or vaping article and which has a nicotine retention capacity which tends towards the nicotine retention capacity of a cellulose acetate filter. In other words, there is a need for a fibrous substrate which provides to the user of a smoking or vaping article a satisfactory experience.

[0006] It is thus to the credit of the inventors to have found that it was possible to meet this need by means of a fibrous substrate comprising a base web, said base web comprising perforated through- holes. Summary

[0007] It is proposed a filter comprising a fibrous substrate as a filter media, said fibrous substrate comprising a base web comprising perforated through-holes, characterized in that the density of the perforated through-holes is from 20 perforated through- holes/cm² to 300 perforated through-holes/cm², in particular 30 perforated through-holes/cm² to 200 perforated through-holes/cm², more particularly from 50 perforated through-holes/cm² to 150 perforated through-holes/cm², even more particularly from 90 perforated through-holes/cm² to 110 perforated through-holes/cm².

[0008] Unexpectedly, in comparison to standard paper filter, the nicotine retention capacity of the filter comprising a base web having a density of perforated through-holes in theses ranges is advantageously improved as it tends towards the nicotine retention capacity of cellulose acetate filters. As a consequence, the filter of the invention provides a satisfactory user experience.

[0009] The Inventors noticed that, in comparison to the nicotine retention of a filter made of a conventional fibrous substrate comprising a base web without perforated through-hole, the nicotine retention of a filter made of a fibrous substrate comprising a base web having a density of perforated through-holes lower than 20 perforated through-holes/cm² shifts away from the nicotine retention capacity of cellulose acetate filters.

[0010] The Inventors also noticed that a base web having a density of perforated through-holes higher than 300 perforated through-holes/cm² does not have the mechanical properties enabling the manufacture of a filter.

[0011] Further, in contrast to a cellulose acetate filter, the filter of the invention may, by virtue of its composition, degrade very rapidly in the environment. This is particularly advantageous, since the environmental impact of the filter of the invention is smaller than the environmental impact of a cellulose acetate filter.

[0012] According to another aspect, a process is proposed for producing a filter as defined above for a smoking article or a vaping article, comprising the following steps: a) producing a base web by a wetlaid process, an airlaid process, a drylaid process or combinations thereof, in particular by a wetlaid process b) obtaining perforated through-holes in the base web to produce a fibrous substrate, c) forming a filter rod from the fibrous substrate produced in step b), d) wrapping the filter rod with a sheet of plug wrap paper, e) depositing an adhesive line at the junction of the sheet of plug wrap paper to obtain a rod of filtering material, and f) cutting the rod of filtering material to produce the filter.

Description of Embodiments

[0013] It is proposed a filter comprising a fibrous substrate as a filter media, said fibrous substrate comprising a base web comprising perforated through-holes, characterized in that the density of the perforated through-holes is from 20 perforated through- holes/cm² to 300 perforated through-holes/cm², in particular 30 perforated through-holes/cm² to 200 perforated through-holes/cm², more particularly from 50 perforated through-holes/cm² to 150 perforated through-holes/cm² even more particularly from 90 perforated through-holes/cm² to 110 perforated through-holes/cm².

[0014] The term "base web" is used herein to mean a fibrous sheet. According to the present invention, the base web is not obtained by hydroentanglement.

[0015] The base web is conventionally a part of the fibrous substrate that is used as filter media in the filters for smoking or vaping articles. The skilled person thus knows how to obtain the base web having the properties required to produce a filter having the required properties. Moreover, the base web is obtainable by a wetlaid process, an airlaid process, a dry laid process or combinations thereof, in particular by a wetlaid process. Accordingly, the fibrous substrate of the filter of the invention is obtainable by a wetlaid process, an airlaid process, a drylaid process or combinations thereof, in particular by a wetlaid process.

[0016] When the fibrous substrate is viewed from above, each of the perforated through-holes may have any kind of shape. The shape of a perforated through-hole is independent from the shape of another perforated through-hole. For example, the shape of the perforated through-hole may be the shape of a circle, an oval, a triangle, a quadrangle such as a rectangle or a square, a pentagon, a hexagon, a heptagon, an octagon, a nonagon or a decagon, in particular the shape of a circle.

[0017] The perforated through-holes in the base web may be obtained by laser drilling, mechanical punching, perforation wheels, electrostatic perforation, air pressure, ultrasonic perforation or combinations thereof.

[0018] When the fibrous substrate is viewed from above, the perforated through-holes may be distributed homogeneously, i.e. according to a quadrangle pattern (square pattern, rectangle pattern) or triangle pattern (equilateral triangle pattern).

[0019] Typically, the base web may comprise more than 50 wt % of wood fibers, in particular 100 wt % of wood fibers.

[0020] Wood fibers may be hardwood pulp, bleached hardwood pulp, softwood pulp, bleached softwood pulp, softwood fluff pulp, lyocell fibers (cellulose fibers which are ground and dissolved in N-methylmorpholine N-oxide monohydrate for the purpose of obtaining fibers with a cross section of variable shape (round, oval, cross-shaped, circular, lamellar cross section) with calibrated length and mass per unit length, which the person skilled in the art can choose depending on their needs), viscose fibers (fibers obtained by dissolving cellulose by means of modification of its hydroxyl groups by carbon disulfide (CS2) and then precipitating it in the presence of sulfuric acid (H2SO4) for the purpose of obtaining fibers with a cross section of variable shape (round, oval, cross-shaped, circular, lamellar cross section) with calibrated length and mass per unit length, which the person skilled in the art can choose depending on their needs) or mixtures thereof, in particular bleached softwood pulp, softwood pulp, softwood fluff pulp, lyocell fibers, viscose fibers or mixtures thereof, more particularly bleached softwood pulp, softwood pulp, softwood fluff pulp or mixtures thereof. [0021] The base web may further comprise natural fibers such as leaf fibers, fruit fibers, seed fibers, bast fibers, stalk fibers, reed fibers or mixtures thereof, in particular leaf fibers, seed fibers, bast fibers or mixtures thereof, more particularly bast fibers.

[0022] For the purposes of the present application, "bast fiber" denotes a plant fiber contained in the bast of the plants.

[0023] The bast fiber may be abaca fiber, hemp fiber, Indian hemp fiber, jute fiber, kenaf fiber, kudzu fiber, coin vine fiber, flax fiber, okra fiber, nettle fiber, papyrus fiber, ramie fiber, sisal fiber, esparto fiber or mixtures thereof, in particular hemp fiber, flax fiber, sisal fiber or mixtures thereof, more particularly flax fiber, sisal fiber, or mixtures thereof.

[0024] For the purposes of the present application, "seed fiber" denotes a fiber obtained from seeds of a plant. The seed fiber may be cotton fiber, kapok fiber, luffa fiber, milkweed fiber or mixtures thereof.

[0025] Prior to the formation of the perforated through-holes, the base web can be impregnated, calendared, coated, sprayed, embossed or combinations thereof.

[0026] The air permeability of the fibrous substrate may be from 1000 CU to 35000 CORESTA Unit (CU), in particular from 5000 CU to 30000 CU, more particularly from 6000 CU to 9000 CU.

[0027] Advantageously, the filter of the present invention comprising a fibrous substrate with an air permeability within these ranges of value has better nicotine retention capacity than the standard paper filters.

[0028] The air permeability of the fibrous substrate can be determined by ISO 2965:2009. The fibrous substrate can be conditioned for at least 30 min at 23°C and 50% humidity before the measurement.

[0029] The standard ISO 536:2012 can be used to determine the basis weight of the fibrous substrate. The fibrous substrate can be conditioned for at least 30 min at 23°C and 50% humidity before the measurement.

[0030] The standard ISO 534:2011 can be used to determine the thickness of fibrous substrate. The measurements were performed on one layer. The fibrous substrate can be conditioned for at least 30 min at 23°C and 50% humidity before the measurement.

[0031] The skilled person knows how to adapt the basis weight and the thickness of the fibrous substrate to reach the required density.

[0032] For instance, the basis weight of the fibrous substrate may be lower than 55 g.rrr², in particular from 12 g.rrr² to 45 g.nr², more particularly from 35 g.nr² to 40 g.nr².

[0033] The thickness of the fibrous substrate may be of from 35 pm to 110 pm, in particular from 80 pm to 100 pm, more particularly from 85 pm to 95 pm.

[0034] The fibrous substrate may further comprise additives commonly used in filter for a smoking or vaping article. [0035] In some circumstances, the fibrous substrate comprises a base web that may have :

- a density of perforated through-holes of from 90 perforated through-holes/cm² to 1 10 perforated through-holes/cm²,

- an air permeability of from 6000 CU to 9000 CU,

- a basis weight of from 35 g.rrr² to 40 g.rrr²,

- a thickness of from 85 pm to 95 pm, and

- when said fibrous substrate is viewed from above the through-holes may have the shape of a circle.

[0036] The fibrous substrate of the filter of the invention can be shaped; in particular, it can be crimped, embossed, folded, compressed or combinations thereof. This shaping can make it possible to modify the properties of the fibrous substrate and therefore the properties of the filter of the invention. For example, through crimping, it is possible, without changing the weight of the filter, to modify the density of the fibrous substrate so as to modify the pressure drop of the filter of the invention, thereby modifying also the pressure drop of a smoking article or vaping article comprising the filter.

[0037] The filter of the present invention may be a filter for a smoking article or a vaping article.

[0038] For the purposes of the present application, “smoking article” denotes an article comprising tobacco and/or any other plant intended to be smoked. For example, the smoking article may be a machine-manufactured cigarette, a roll-your-own cigarette or a make-your-own cigarette.

[0039] Typically, the filter for a smoking article has a right circular cylindrical shape and comprises an outer envelope of plug wrap paper for a smoking article, in particular for a cigarette, and the fibrous substrate as defined above located within the outer envelope.

[0040] For the purposes of the present application, “vaping article” denotes an article comprising tobacco and/or any other plant intended to be vaped, which is intended to be inserted into a device which heats the tobacco and/or the plant without burning said tobacco/plant and which enables delivery of an aerosol to a user. For example, the vaping article can be a tobacco stick.

[0041] Typically, the filter for a vaping article has a right circular cylindrical shape and comprises an outer envelope of plug wrap paper for a vaping article, in particular for a tobacco stick, and the fibrous substrate as defined above located within the outer envelope.

[0042] The filter of the invention can have a density lower than 220 g/cm³, in particular from 170 g/cm³ and 200 g/cm³, more particularly from 195 g/cm³ to 210 g/cm³.

[0043] Typically, the density of the filter is measured after manufacture of the filters, by dividing the mass of the filter by its volume. For a filter having a right circular cylindrical shape, the volume of the filter (Vfiiter) is calculated by the following formula: Vfiiter = TT*L*r², in which r denotes the radius of the filter and L denotes the length of the filter.

[0044] The density of the filter of the invention is lower than the density of the standard paper filters.

Without wishing to be bound to any theory, the inventors are of the opinion that the low density of the filter of the invention, advantageously, may allow less interception of nicotine by the fibers of the fibrous substrate thereby increasing the amount of nicotine delivered to the user.

[0045] The filter of the invention can comprise:

- an outer envelope of plug wrap paper for a filter for a smoking or vaping article, and

- the fibrous substrate within the outer envelope.

[0046] The filter of the invention can have a right circular cylindrical shape.

[0047] According to another aspect, the present invention also relates to a smoking article comprising a filter as defined above.

[0048] According to another aspect, the present invention also relates to a vaping article comprising a filter as defined above.

[0049] The present invention also relates to a process for producing a filter as defined above for a smoking article or a vaping article, comprising the following steps: a) producing a base web by a wetlaid process, an airlaid process, a drylaid process or combinations thereof, in particular by a wetlaid process b) obtaining the perforated through-holes in the base web to produce a fibrous substrate, c) forming a filter rod from the fibrous substrate produced in step b), d) wrapping the filter rod with a sheet of plug wrap paper, e) depositing an adhesive line at the junction of the sheet of plug wrap paper to obtain a rod of filtering material, and f) cutting the rod of filtering material to produce the filter.

[0050] The fibrous substrate and the base web are as defined above.

[0051] The wetlaid, airlaid and drylaid processes are conventional processes known to the skilled person. The skilled person knows how to adapt the parameters of these processes to produce the base web during step a).

[0052] Step b) of obtaining perforated through-holes in the base web may be performed by laser drilling, mechanical punching, perforation wheels, electrostatic perforation, air pressure or ultrasonic perforation.

[0053] These processes to perforate through-holes and obtain the perforated through-holes are well known by the skilled person. Accordingly, the skilled person knows how to adapt the parameters of these processes to produce the fibrous substrate.

[0054] The fibrous substrate produced in step b) can be shaped.

[0055] Therefore, the process may comprise, between step b) and step c), a step of shaping the fibrous substrate by slitting, crimping, embossing, folding, compression or combination thereof.

[0056] Slitting the fibrous substrate may be useful to modify the pressure drop of the filter.

[0057] Steps c) to e) are steps well known to the skilled person. The skilled person knows how to adapt the parameters of these processes to produce the filter of the invention. Examples

[0058] Example 1 : Fibrous substrate manufacturing

[0059] A base web was produced with bleached softwood fibers by a wetlaid process.

[0060] This base web is cut into four pieces and through-holes were perforated in three of these four base webs by mechanical punching process to produce three fibrous substrates.

[0061] The properties of the remaining base web and of three fibrous substrates are presented in Table 1 .

[0062] [Table 1]

[0063] Example 2: Filter manufacturing

[0064] Filters for a smoking article were manufactured with a nonporous plug wrap paper having a basis weight of 23.5 g/m² as an outer envelope and the fibrous substrate of Example 1.1 having a perforated through-hole density of 100 perforated through-holes/cm² by a standard method for manufacturing filters by crimping (referred as filter 100 through-holes/cm² in Table 2 and 3 below).

[0065] A filter for a smoking article was manufactured with a nonporous plug wrap paper having a basis weight of 23.5 g/m² as an outer envelope and the fibrous substrate of Comparative Example 1 having a perforated through-hole density of 11 perforated through-holes/cm² by a standard method for manufacturing filters by crimping (referred as filter 11 through-holes/cm² in Table 2 and 3 below).

[0066] A filter for a smoking article was manufactured with a nonporous plug wrap paper having a basis weight of 23.5 g/m² as an outer envelope and the remaining base web of Example 1 by a standard method for manufacturing filters by crimping (referred as Comparative paper filter in Tables 2 and 3 below).

[0067] The properties of these three filters were compared with the properties of a commercial cellulose acetate filter from Marlboro Red France™.

[0068] The characteristics of the filters are given in Table 2 below. [0069] Table 2 demonstrates that the filter according to the invention has a lower filter density than the comparative paper filter.

[0070] [Table 2]

[0071] Example 3: Manufacture and characterization of cigarettes

[0072] Cigarettes were prepared using the filters rods described in Example 2. The filters were cut to 21 mm length. To form the cigarettes, the rods of tobacco were assembled with the cut filters using nonporous 35 g/m² tipping paper. A commercial “American blend” tobacco was used to form the rods of tobacco. The cigarettes were prepared with a pressure drop similar to that of the commercial cigarette. The ventilation of the cigarettes was blocked.

[0073] The cigarettes prepared were smoked on a Borgwaldt RM20 smoking machine in accordance with the standard ISO 3308:2000. The cigarette pressure drop (cigarette PD in Table 3 below) was measured in accordance with the standard ISO 6565:2002.

[0074] The nicotine content in the smoke was measured in accordance with the standard ISO 10315:2000. Table 3 presents the difference between the content of nicotine in the smoke produced by the cigarettes with the commercial cellulose acetate filter and the content of nicotine in the smoke produced by the cigarettes with the filter 100 perforated through-holes/cm², and the cigarette with the filter 11 perforated through-holes/cm² or the comparative paper filter. These differences are noted Delta nicotine in Table 3 below.

[0075] Table 3 demonstrates that, with an equivalent pressure drop, the difference between the content of nicotine in the smoke produced by the cigarettes with the filter 100 perforated through- holes/cm² according to the invention and the content of nicotine in the smoke produced by the cigarettes with the commercial cellulose acetate filter is lower than the difference between the content of nicotine in the smoke produced by the cigarettes with the filters not according to the invention and the content of nicotine in the smoke produced by the cigarettes with the commercial cellulose acetate filter.

[0076] Accordingly, the filter of the present invention provides to the user a more satisfactory experience than the comparative paper filter.

[0077] [Table 3]

Claims

[Claim 1] A filter comprising a fibrous substrate as a filter media, said fibrous substrate comprising a base web comprising perforated through-holes, characterized in that the density of the perforated through-holes is from 20 perforated through- holes/cm² to 300 perforated through-holes/cm².

[Claim 2] Filter according to Claim 1 , wherein, when the fibrous substrate is viewed from above, each of the through-holes has a shape of a circle, an oval, a triangle, a quadrangle, a pentagon, a hexagon, a heptagon, an octagon, a nonagon or a decagon.

[Claim 3] Filter according to Claim 1 or Claim 2, wherein, when the fibrous substrate is viewed from above, the perforated through-holes are distributed homogeneously.

[Claim 4] Filter according to anyone of Claims 1 to 3, wherein the fibrous substrate has an air permeability from 1000 CU to 35000 CU.

[Claim 5] Filter according to any one of Claims 1 to 4, wherein the fibrous substrate has a basis weight lower than 55 g.rrr².

[Claim 6] Filter according to any one of Claims 1 to 5, wherein the fibrous substrate has a thickness of from 35 pm to 110 pm.

[Claim 7] Filter according to any one of Claims 1 to 6, wherein the fibrous substrate is obtainable by a wetlaid process, an airlaid process, a dry laid process or combinations thereof.

[Claim 8] Filter according to any one of Claims 1 to 7 for a smoking article or a vaping article.

[Claim 9] Smoking article comprising a filter as defined in Claim 8.

[Claim 10] Vaping article comprising a filter as defined in Claim 8.

[Claim 11] Process to produce a filter for a smoking article or a vaping article as defined in Claim 8, comprising the following steps: a) producing a base web by a wetlaid process, an airlaid process, a drylaid process or combinations thereof, b) obtaining perforated through-holes in the base web to produce a fibrous substrate, c) forming a filter rod from the fibrous substrate produced in step b), d) wrapping the filter rod with a sheet of plug wrap paper, e) depositing an adhesive line at the junction of the sheet of plug wrap paper to obtain a rod of filtering material, and f) cutting the rod of filtering material to produce the filter.

[Claim 12] Process according to claim 11 , wherein step b) is performed by laser drilling, mechanical punching, perforation wheels, electrostatic perforation, air pressure or ultrasonic perforation.