Paper or nonwoven filter media with plug wrap paper comprising a fibrous substrate

Abstract

The present disclosure relates to a plug wrap paper for use in a smoking or vaping article.

Description

PAPER OR NONWOVEN FILTER MEDIA WITH PLUG WRAP PAPER COMPRISING A FIBROUS SUBSTRATETechnical Field

[0001] The present disclosure relates to a filter advantageously used in a smoking article. The filter comprising a filter media and a plug wrap paper.Backg ound Art

[0002] A smoking or a vaping article can comprise a filter having a right circular cylindrical shape. A common filter can comprise at least two parts: one filter media and one plug wrap paper. The plug wrap paper is the outer envelope of the filter, and the filter media is located within this outer envelope. The filter 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 produced by the smoking or vaping article, such as tar.

[0003] The filter media of a smoking or vaping article can be made from acetate cellulose. Acetate cellulose filters are known to be a good compromise between production price and customer’s experience. In particular, filters comprising filter media made from acetate cellulose exhibit good hardness, good tar retention and satisfactory pressure drop.

[0004] The huge environmental impact caused by waste of tobacco products with filters containing acetate cellulose, discarded directly into the environment, needs to be reduced. Directive (EU) 2019 / 904 of the European parliament and of the council of 5 June 2019 on the reduction of the impact of certain plastic products on the environment has been voted to tackle plastic pollution and marine litter to accelerate the transition to a circular and resource-efficient plastics economy. Specific rules and targets apply to certain areas, including acetate cellulose filters of smoking articles.

[0005] For this reason, research has been carried out to find new filter media that comply with the aforementioned European directive as for example filter media made of paper substrate. As the paper substrates are biodegradable, the filters comprising a paper substrate filter media can degrade rapidly.

[0006] When an acetate cellulose filter media of a certain volume is replaced by a paper filter media having an equivalent volume, the hardness of the filter decreases, the pressure drop through the paper filter media decreases, and channeling effect may occur. Also, paper filter media has higher retention rate that acetate cellulose.

[0007] To avoid channeling effect, to increase the pressure drop through the paper filter media and the hardness of the filter, some have suggested stuffing the filter with a large quantity of paper filter media. However, such a solution leads to a more expensive filter since it uses more filter media and since paper filter media are generally more expensive than cellulose acetate filter media. It can also result in a filter having too high retention rate.Summary

[0008] The inventors have discovered a filter that improves the situation, taking into account all the problems raised above.

[0009] According to a first aspect of the present invention, there is provided a filter comprising at least one filter media and at least one plug wrap paper,wherein the plug wrap paper is the outer envelope of the filter and the filter media is located within this outer envelope,wherein the plug wrap paper comprises a fibrous substrate, and the thickness of the plug wrap paper is from 50 pm to 250 pm, and wherein the filter media is chosen among a paper substrate, a nonwoven substrate or a combination thereof.

[0010] The filter according to the invention is free of cellulose acetate and may thus comply with the EU directive 2019 / 904.

[0011] Advantageously the filter of the present invention can also be provided at lower cost and is satisfactory to the users since it has satisfactory hardness, pressure drop, while avoiding channeling effect.

[0012] Nevertheless, the Inventors are of the opinion that these advantageous achievements result from the combination of the density and the thickness of the plug wrap paper. Indeed, without wishing to be bound by any theory, the Inventors are of the opinion that:this lower internal volume enables to obtain a satisfactory pressure drop with a lower amount of filter media, and thus a lower cost, due to an optimized compression of the filter media in said internal volume, andthis optimized compression avoid channeling effect in the filter of the present invention.

[0013] The term "hardness" used throughout this specification denotes the resistance to deform. Hardness is generally expressed as a percentage. The percentage is for example the fraction between the diameter of a filter before applying a load compared with the same diameter whilst applying load F.

[0014] The term “pressure drop” used throughout this specification refers to the difference in pressure between the air entering the article and the air exiting it during inhalation. This parameter is a measure of the airflow resistance within the smoking or vaping device, which affects the ease of draw and user experience. The pressure drop is typically quantified in accordance with the standard ISO 6565:2002. The unit of measurement for pressure drop is usually millimetres water gauge (mmWG), pascals (Pa) or inches of water (inH2O).

[0015] The term “channeling effect” used throughout this specification refers to a phenomenon resulting from the use of filters comprising filter media made from a paper substrate, a nonwoven substrate or a combination thereof. These filter media, typically made of biodegradable materials like paper, tend to develop irregularities in their perforations. Though purely visual, this effect may mislead users into believing their filter might function less effectively.

[0016] According to a second aspect of the present invention, there is provided a plug wrap paper comprising a fibrous substrate, whereinthe density of the plug wrap paper is below 600 mg / cm3, in particular from 200 mg / cm3to 500 mg / cm3, more particularly from 250 mg / cm3to 450 mg / cm3and,the thickness of the plug wrap paper is from 50 pm to 250 pm, in particular from 55 pm to 240 pm, more particularly from 60 pm to 230 pm.

[0017] According to a third aspect of the present invention, there is provided a process to produce a filter according to the first aspect of the present invention, comprising the following steps:wrapping a filter media chosen among a paper substrate, a nonwoven substrate or a combination thereof with a sheet of a plug wrap paper according to the present disclosure, bonding, for instance by depositing an adhesive line, a junction of the sheet of plug wrap paper to obtain a filter rod, andcutting the filter rod to produce at least one filter.

[0018] The process according to the present invention enables to produce efficiently the filter of the present invention.

[0019] According to a fourth aspect of the present invention, there is provided a process to produce a plug wrap paper according to the second aspect of the present invention.Description of figuresFig. 1

[0020] [Fig. 1] is a perspective view of a filter according to one aspect of the present invention. Description of embodiments

[0021] Reference is now made to Figure 1.

[0022] It is proposed a filter 10 comprising at least one filter media 20 and at least one plug wrap paper 30, wherein the plug wrap paper 30 is the outer envelope of the filter 10 and the filter media 20 is located within this outer envelope,wherein the plug wrap paper 30 comprises a fibrous substrate,wherein the thickness E of the plug wrap paper 30 is from 50 pm to 250 pm, in particular from 55 pm to 240 pm, more particularly from 60 pm to 230 pm, andwherein the filter media 20 is chosen among a paper substrate, a nonwoven substrate or a combination thereof.

[0023] The standard ISO 534:2011 can be used to determine the plug wrap thickness paper 30. The measurements can be performed on one layer. The plug wrap paper 30 can be conditioned for at least 30 min at 23°C and 50% humidity before the measurement and then measured the thickness at a predetermined pressure.

[0024] The standard ISO 536:2012 can be used to determine the basis weight of the plug wrap paper 30. The plug wrap paper 30 can be conditioned for at least 30 min at 23°C and 50% humidity before the measurement.

[0025] Typically, the plug wrap paper 30 may have- a basis weight from 20 g / m2to 90 g / m2, and preferably from 30 g / m2to 80 g / m2, - a thickness E between 60 pm and 250 pm, preferably from 130 pm to 240 pm.

[0026] The density of the plug wrap paper 30 can be below 600 mg / cm3, in particular from 200 mg / cm3to 500 mg / cm3, more particularly from 250 mg / cm3to 450 mg / cm3. It is for example calculated by dividing its basis weight by its thickness E. Preferably, the basis weight and the thickness of the plug wrap paper 30 are measured after manufacture of the plug wrap paper.

[0027] The density and thickness of the plug wrap paper of the present invention can enable the internal volume of the outer envelope of the filter of the present invention to be lower than the internal volume of the outer envelope of common filter.

[0028] The skilled person knows how to adapt the basis weight and the thickness E of the plug wrap paper 30 to reach satisfactory density of the plug wrap paper 30.

[0029] For instance, the basis weight of the plug wrap paper 30 may be around 23 g / m2, 32 g / m2, 62 g / m2or 78 g / m2.

[0030] For instance, the thickness of the plug wrap paper 30 may be around 61 pm, 114 pm, 148 pm or 202 pm.

[0031] Typically, the permeability of the plug wrap paper 30 may be from 2000 Coresta Unit (CU) to 20 000 Coresta Unit (CU), in particular from 3 000 to 15 000 CU, more particularly from 3500 to 10 000 CU.

[0032] The standard ISO 2965:2009 can be used to determine the permeability of the plug wrap paper 30. The plug wrap paper 30 can be conditioned for at least 30 min at 23°C and 50% humidity before the measurement.

[0033] The fibrous substrate of the plug wrap paper 30 may be obtainable by a wetlaid process, in particular by a wetlaid process involving a machine with an inclined wire part.

[0034] For the purposes of the present application, the term “fibrous substrate” denotes a base web made of fibers.

[0035] The fibers of the fibrous substrate may preferably be chosen from wood fibers, leaf fibers, fruit fibers, seed fibers, bast fibers, stalk fibers, reed fibers or mixtures thereof, in particular wood fibers.

[0036] Typically, the fibrous substrate may comprise more than 50 wt % of wood fibers, in particular 100 wt % of wood fibers.

[0037] 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 inN-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.

[0038] The fibrous substrate 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.

[0039] For the purposes of the present application, "bast fiber" denotes a plant fiber contained in the bast of the plants. 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.

[0040] 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.

[0041] In addition, the fibrous substrate 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 basis weight of the fibrous substrate, to adapt the density of the fibrous substrate so as to, for instance, 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.

[0042] The filter 10 of the present invention is not limited to a single plug wrap paper. For example, the filter media may be wrapped by two or more plug wrap papers. Also, the filter may comprise two or more plugs of filter media. The two or more plugs have the same filter media or different filter media, the combination of which possibly leading to an improved property of the filter.

[0043] The filter media 20 of the filter 10 of the present invention is chosen among a paper substrate, a nonwoven substrate or a combination thereof.

[0044] For the purposes of the present application, "paper substrate" denotes a sheet consisting of cellulosic fibers obtained by a wetlaid process.

[0045] For the purposes of the present application, "nonwoven substrate" denotes a manufactured sheet consisting of a web or ply of directionally or randomly oriented cellulosic fibers bonded togetherby a binder. The airlaid process and the drylaid process are particularly suitable to produce the nonwoven substrate. Thus, the nonwoven substrate of the filter media 20 can be obtained by an airlaid process or a drylaid process.

[0046] The fibers of the paper substrate and of the nonwoven substrate are as defined above in relation with the fibers of the fibrous substrate of the plug wrap paper 30.

[0047] For the purposes of the present application, "binder" denotes a compound having properties enabling consolidation of the nonwoven substrate. For example, the binder can be a natural polymer, a synthetic polymer or copolymer or a mixture thereof.

[0048] The natural polymer can be a polysaccharide, a cellulose derivative, or a mixture thereof. The polysaccharide which can be used as binder can be a polysaccharide or a polysaccharide derivative. For example, starch, dextrin, arabic gum or a mixture thereof can be used as binder, in particular starch.

[0049] For example, the cellulose derivative can be ethyl cellulose, methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, an alkali metal salt of carboxymethyl cellulose, or a mixture thereof, in particular carboxymethyl cellulose. As alkali metal of the carboxymethyl cellulose salt, mention may be made of potassium, sodium, and magnesium.

[0050] The synthetic polymer or copolymer can, for example, be a latex, a polyvinyl alcohol, an ethylene-vinyl alcohol, a polyvinyl acetate, a polyvinyl chloride, a styrene-butadiene, a polybutadiene, polyacrylics, an ethylene-vinyl acetate, or a mixture thereof, in particular ethyl-vinyl alcohol, polyvinyl acetate, polyvinyl alcohol or a mixture thereof.

[0051] For the purposes of the present application, “latex” refers to a binder resulting from an emulsion of polymer microparticles in water. The polymer microparticles are present as such in the nonwoven substrate of the present invention.

[0052] Typically, the latex may have a glass transition temperature (Tg) from -20°C to 45°C, in particular -15°C to 36°C, more particularly from -10°C to 20°C.

[0053] Typically, the latex can be chosen from copolymers and polymers comprising ethylene, vinyl acetate, butadiene, styrene, vinyl chloride, acrylic esters, urethanes, and mixtures thereof, in particular from copolymers and polymers comprising ethylene, vinyl acetate, more particularly from copolymers of ethylene and vinyl acetate.

[0054] According to one particular embodiment, the latex has a glass transition temperature from -10°C to 20°C and is a copolymer of ethylene and vinyl acetate.

[0055] The copolymer of ethylene and vinyl acetate is also known as ethylene-vinyl acetate (EVA) and poly(ethylene-vinyl acetate) (PEVA).

[0056] The nonwoven substrate preferably comprises cellulosic fibers and a binder, the cellulosic fibers may represent from 70% to 99%, in particular from 80% to 98%, more particularly from 85% to 98% by weight of solids of said nonwoven substrate, the binder may represent from 1% to 30%,in particular from 2% to 20%, more particularly from 2% to 15% by weight of solids of said nonwoven substrate.

[0057] The basis weight of the filter media can be from 20 g / m2to 75 g / m2, in particular from 23 g / m2to 70 g / m2, more particularly from 25 g / m2to 60 g / m2.

[0058] The standard ISO 536:2012 can be used to determine the basis weight of the paper substrate and of the nonwoven substrate. The substrate is conditioned for at least 16 hours at 23°C and 50% relative humidity before the measurement.

[0059] The thickness of the nonwoven substrate or paper substrate of the filter media may be from 200 pm to 2000 pm, in particular from 250 pm to 2 000 pm, more particularly from 300 pm to 1 500 pm, for instance 500 pm.

[0060] To measure the thickness of the nonwoven substrate, it is possible to use a dead-weight micrometer comprising a 25 cm2measuring head with two planar, parallel and circular pressure surfaces. During the measurement, the nonwoven substrate is placed between the two pressure surfaces for 10 seconds. The pressure exerted between the pressure surfaces during the measurement of the thickness can be 100 kPa. The substrate is conditioned for at least 16 hours at 23°C and 50% relative humidity before the measurement.

[0061] The filter media can have a density from 7 mg / cm3to 120 mg / cm3, in particular from 7 to 80 mg / cm3, more particularly from 8 mg / cm3to 70 mg / cm3, even more particularly from 10 mg / cm3to 60 mg / cm3.

[0062] Typically, the density of the filter media is calculated by dividing its basis weight by its thickness.

[0063] The paper substrate and the nonwoven substrate can be shaped, in particular it can be crimped, folded or rolled up. This shaping can make it possible to modify the properties of the paper substrate and therefore the properties of the filter media comprising it. For example, crimping can make it possible to modify the density of the paper substrate and thus to increase or reduce the pressure drop of the filter media comprising the paper substrate without changing the weight of the filter media. In this way, the shaping of the paper substrate by known processes such as crimping renders it easily adaptable to different filters.

[0064] Alternatively, the nonwoven substrate may not be crimped before the formation of the filter media.

[0065] Advantageously, the filter 10 has a standard outer diameter Df, preferably from 5 mm to 10 mm, preferably from 6 to 8 mm, for instance the outer diameter Df of the filter 10 is about 7,8 mm.

[0066] The outer diameter Df of the filter 10 is the diameter Dm of the filter media 20 plus twice the thickness of the plug wrap paper E.

[0067] The length L of the filter 10, measured in a direction substantially parallel to the longitudinal axis of the filter 10, may have any suitable value. However, it may be convenient for the filter’s length L to be substantially the same as in conventional smoking articles or vaping articles. The length Ldesignates the total length of the filter 10, including the plug of filter media. That is, if the filter 10 comprises one or more plug of filter media, the length is the total length of all the plug of filter media. If the filter 10 comprises only one filter media, the length is the length of only the plug of filter media.

[0068] Preferably, the filter 10 has a length L from about 15 mm to 40 mm. Even more preferably, the filter 10 has a length L from about 18 mm to about 27 mm. In one embodiment, the filter 10 has a length L of about 27 mm. In another embodiment, the filter 10 has a length L of about 21 mm.

[0069] The present invention is also directed to a smoking article comprising a filter 10 according to the first aspect of the invention. The present invention is also directed to a vaping article comprising a filter 10 according to the first aspect of the invention.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] The invention is also directed to a plug wrap paper comprising a fibrous substrate, wherein the density of the plug wrap paper is below 600 mg / cm3, in particular from 200 mg / cm3to 500 mg / cm3, more particularly from 250 mg / cm3to 450 mg / cm3and,the thickness of the plug wrap paper is from 50 to 250 pm, preferably from 55 to 240 pm, even more preferably from 60 to 230 pm, for instance from 110 pm to 250 pm, or from 130 pm to 240 pm, or from 120 pm to 230 pm.

[0075] The plug wrap paper according to the invention is as defined above in relation to the filter according to the invention.

[0076] The invention is also directed to a process to produce the filter 10 as defined above, advantageously for a smoking article or a vaping article, comprising the following steps:wrapping a filter media 20 chosen among a paper substrate, a nonwoven substrate or a combination thereof with a sheet of plug wrap paper 30 comprising a fibrous substrate as defined above,depositing an adhesive line at the junction of the sheet of plug wrap paper 30 to obtain a filter rod, andcutting the filter rod to produce the filter 10.

[0077] The process to produce the filter 10 as defined above may also comprise, prior to the step described above, the following steps:producing a base web by a wetlaid process, an airlaid process, a drylaid process or combinations thereof,forming a filter media 20 from the base web,

[0078] The filter media 20 and the plug wrap paper 30 involved in this process to produce the filter 10 are as defined above in relation with the filter 10 of the present invention.

[0079] 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).

[0080] The filter media 20 formed in the process defined above has preferably a right circular cylindrical shape.

[0081] The filter media 20 formed in the process defined above can be shaped. Therefore, the process may comprise, another step of shaping the filter media 20 by crimping, embossing, folding, compression or combination thereof to obtain a shaped filter media, said filter media being involved into step of wrapping the filter media 20 with a sheet of plug wrap paper 30 comprising a fibrous substrate.

[0082] Shaping the paper substrate may be useful to modify the pressure drop of the filter media.

[0083] The plug wrap paper may advantageously be produced by a process comprising the following steps:producing a fibrous substrate by a wetlaid processs, in particular a wetlaid processs involving a machine with an inclined wire part,cutting the fibrous substrate to produce the plug wrap paper.

[0084] The wetlaid process, in particular a wetlaid process involving a machine with an inclined wire part is a conventional process known to the skilled person. The skilled person knows how to adapt the parameters of this process to produce the fibrous substrate.

[0085] The invention is also directed to process to produce the plug wrap paper 30 of the present invention as defined above comprising the following steps:producing a fibrous substrate by a wetlaid processs, in particular a wetlaid processs involving a machine with an inclined wire part,cutting the fibrous substrate to produce the plug wrap paper.Example

[0086] Filters of 108 mm length were manufactured.

[0087] The filter media is a nonwoven material, more particularly an airlaid nonwoven material having th e following characteristics: 1mm (thickness) and 50 g / m2(basis weight). The nonwoven substrate was crimped with a 0.45mm crimping depth.

[0088] To form the filter rods, two plug wraps paper manufactured by a wetlaid process were used with the prope rties contained in the following table 1 where S1 is a plug wrap paper according to the present invention and S2 is a comparative plug wrap paper.

[0089] [Table 1]

[0090] Manufactured 108 mm filter comprising either S1 or S2 plug wrap paper as described above were characterized. The filter ‘with S1 ’ comprises the filter media as defined above, wrapped withinthe plug wrap paper S1. The filter ‘with S2’ comprises the filter media as defined above, wrapped within the plug wrap paper S2. Results are within the following table 2.

[0091] [Table 2]

[0092] The results from the examples demonstrate that using the plug wrap paper S1 , which has a higher thickness, results in a higher filter pressure drop compared to the plug wrap paper S2, despite both having the same quantity of nonwoven substrate and filter diameter. Specifically, the filter pressure drop for S1 is increased by 70 mmWG, which corresponds to a 32% increase over S2. Thisindicates that the increased thickness of the plug wrap paper S1 effectively reduces the available filter area, thereby enhancing the pressure drop for the same amount of nonwoven substrate.

Claims

Claims

1. A filter (10) comprising at least one filter media (20) and at least one plug wrap paper (30), wherein the plug wrap paper (30) is the outer envelope of the filter (10) and the filter media (20) is located within this outer envelope,wherein the plug wrap paper (30) comprises a fibrous substrate, and the thickness of the plug wrap paper (30) is from 50 pm to 250 pm, andwherein the filter media (20) is chosen among a paper substrate, a nonwoven substrate or a combination thereof.

2. The filter according to claim 1 , wherein the density of the plug wrap paper is below 600 mg / cm3.

3. The filter according to claims 1 or 2, wherein the fibrous substrate of the plug wrap paper (30) has a basis weight between 20 g / m2to 90 g / m2.

4. The filter according to anyone of claims 1 to 3, wherein the permeability of the fibrous substrate of the plug wrap paper (30) is from 2 000 to 20000 CORESTA Unit (CU).

5. The filter according to any one of claims 1 to 4, wherein the fibers of the fibrous substrate of the plug wrap paper (30) are chosen from wood fibers, leaf fibers, fruit fibers, seed fibers, bast fibers, stalk fibers, reed fibers or mixtures thereof.

6. The filter according to any one of claims 1 to 5, wherein the filter has an outer diameter Df from 5 mm to 10 mm.

7. Smoking article comprising a filter (10) as defined in any one of claim 1 to claim 6.

8. Vaping article comprising a filter (10) as defined in any one of claim 1 to claim 6.

9. A plug wrap paper (30) comprising a fibrous substrate, wherein- the density of the plug wrap paper is below 600 mg / cm3, and- the thickness of the plug wrap paper is from 50 pm to 250 pm.

10. The plug wrap paper (30) according to claim 9, wherein the fibrous substrate of the plug wrap paper (30) has a basis weight between 20 g / m2to 90 g / m2.

11. The plug wrap paper according to claims 9 or 10, wherein the permeability of the fibrous substrate of the plug wrap paper (30) is from 2 000 to 20000 CORESTA Unit (CU).

12. Process to produce a filter (10) according to any one of claims 1 to 6 comprising the following steps:wrapping a filter media chosen among a paper substrate, a nonwoven substrate or a combination thereof with a sheet of a plug wrap paper according to any one of claims 9 to 11 , bonding a junction of the sheet of plug wrap paper to obtain a filter rod, andcutting the filter rod to produce at least one filter.

13. Process to produce a plug wrap paper according to anyone of claims 9 to 11 , the process comprising the following steps:producing a fibrous substrate by a wetlaid processs,cutting the fibrous substrate to produce the plug wrap paper.

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