Festooned bale of nonwoven substrate

Abstract

The present invention relates to a filter comprising, as filter media, a nonwoven substrate adapted to be folded in festooned bales.

Description

DescriptionTitle: Festooned bale of nonwoven substrateTechnical field

[0001] A subject of the invention is a filter comprising, as filter media, a nonwoven substrate adapted to be folded in festooned bales. In particular, this filter can be used as filter for a smoking or vaping article.Prior art

[0002] A smoking or a vaping article commonly comprises a filter having a right circular cylindrical shape. A common filter comprises 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] Filter media of a smoking or vaping article is generally made from cellulose acetate tow. Cellulose acetate filters are known to be a good compromise between production price and customer’s experience. In particular, filters comprising filter media made with cellulose acetate tow exhibit good hardness, good nicotine retention and satisfactory taste.

[0004] The huge environmental impact caused by waste of tobacco products with filters containing cellulose acetate, 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 cellulose acetate filters of smoking article.

[0005] For this reason, many studies have been carried out to find filter media alternatives that comply with the aforementioned European directive as for examplefilter media made of paper substrate or nonwoven substrate. As paper substrates and nonwoven substrates can be made with natural fibers, the filters comprising these substrates have lower environmental impact.

[0006] Paper substrate is delivered in bobbins of several thousands of meters which allow filter manufacturers to operate at high speed with an acceptable number of bobbins changes. Nonwoven substrate being less dense than paper substrate, the length of nonwoven substrate on a single bobbin is much shorter, i.e. hundred meters. Shorter bobbin length requires very frequent bobbin changes. The increase of the frequency of bobbin changes causes a reduction of efficiency in the filters manufacturing process. Additionally due to low density of nonwoven substrate, the thickness of nonwoven near the core of the bobbin could be different from the one on the external layer of the bobbin, which increases the unwanted variability of filter pressure drop.Technical problem

[0007] There is therefore a need to optimize the process to manufacture compliant filters comprising nonwoven substrate.

[0008] It is thus to the credit of the inventors to have found that it was possible to meet this need by means of a filter comprising a nonwoven substrate with a specific elongation and spring-back distance.Summary

[0009] It is proposed a filter comprising a nonwoven substrate as filter media, said nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99%, in particular from 80% to 98%, more particularly from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 1 % to 30%, in particular from 2% to 20%, more particularly from 5% to 18% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it has an elongation from 4.5% to 40%, in particular from 6% to 40%, more particularly from 8% to 30%, even more particularly from 10% to 20%.

[0010] More particularly, it is proposed a filter comprising a nonwoven substrate as filter media, said nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99%, in particular from 80% to 98%, more particularly from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 1 % to 30%, in particular from 2% to 20%, more particularly from 5% to 18% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it presents a spring-back distance bigger than or equal to 0.6 cm, in particular from 0.8 cm to 1 .5 cm, more particularly from 1 cm to 1 .2 cm, and it has an elongation from 6% to 40%, in particular from 8% to 30%, more particularly from 10% to 20%.

[0011] Advantageously, the nonwoven substrate of the filter of the invention can be folded in festooned bales.

[0012] Since the length of nonwoven substrate in a festooned bale is greater than the length of the same nonwoven substrate in a bobbin, then the process to manufacture the filters of the invention is optimized since the frequency of the replacement of festooned bales is reduced in comparison to the replacement of bobbins.

[0013] Moreover, in contradiction to bobbins, the thickness of nonwoven substrate in a festooned bale does not significantly vary. Therefore, the pressure drop of different filters of the invention does not significantly vary.

[0014] Without wishing to be bound by any theory, the inventors are of the opinion that the nonwoven substrate of the filter of the invention can be folded in festooned bales and then involved in the manufacturing process of the filter of the present invention thanks to its elongation, in particular thanks to the combination of its spring-back distance and its elongation. Indeed, such elongation, in particular such combination enables the nonwoven substrate of the filter of the invention:- to resist to the tear forces involved in the festooning process and so, to limit the broke of said nonwoven substrate. Tear forces are important for festooning process because in some cases the distance between the end of slitting line of thenonwoven substrate and the bale could be more than 15 meters;- to recover its original properties while being unfolded on filter making lines even though it was previously folded in festooned bales; and- to resist to the forces involved in the manufacturing process of filters comprising said nonwoven substrate.

[0015] Moreover, festooned bales made of the nonwoven substrate of the filter of the present invention are easily transportable, do not require complex unwind devices and can be used on the machines manufacturing the filter comprising cellulose acetate tow.

[0016] Advantageously, the filter of the invention is adapted to be used as a filter for a smoking or vaping article.

[0017] According to another aspect, a smoking or a vaping article comprising the filter of the present invention is proposed.

[0018] According to another aspect, a nonwoven substrate is proposed, said nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99%, in particular from 80% to 98%, more particularly from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 1 % to 30%, in particular from 2% to 20%, more particularly from 5% to 18% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it has an elongation from 4.5% to 40%, in particular from 6% to 40%, more particularly from 8% to 30%, even more particularly from 10% to 20%.

[0019] According to another aspect, a nonwoven substrate is proposed, said nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99%, in particular from 80% to 98%, more particularly from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 1 % to 30%, in particular from 2% to 20%, more particularly from 5% to 18% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it presents a spring-back distance bigger than or equal to 0.6 cm, in particular from 0.8 cm to 1 .5 cm, more particularly from 1 cm to 1 .2 cm, andit has an elongation from 6% to 40%, in particular from 8% to 30%, more particularly from 10% to 20%.

[0020] According to another aspect, a festooned bale made of the nonwoven substrate of the invention is proposed.

[0021] According to another aspect, a process is proposed for producing the filter, in particular the filter for a smoking or vaping article, of the present invention as defined above, said process comprising the following steps: a) forming a rod of nonwoven substrate from a festooned bale made of a nonwoven substrate, b) wrapping the rod of nonwoven substrate with a sheet of plug wrap paper, c) depositing an adhesive line and joining the sheet of plug wrap paper to obtain a rod of filtering material, and d) cutting the rod of filtering material to produce the filter.

[0022] According to another aspect, a process is proposed for producing the nonwoven substrate of the invention as defined above comprising the following steps: i) producing a web from natural fibers by an airlaid process or a drylaid process, in particular an airlaid process, ii) introducing the binder into the web, and iii) drying the web resulting from step ii) to obtain the nonwoven substrate.

[0023] According to another aspect, a process is proposed for producing the festooned bale of the present invention as defined above, said process comprising the following step: a’) festooning the nonwoven substrate of the present invention to produce the festooned bale.Brief description of drawing

[0024] Figure 1 illustrates the measurement of the spring-back distance D.Detailed description of the invention

[0025] It is proposed a filter comprising a nonwoven substrate as filter media, said nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99%, in particular from 80% to 98%, more particularly from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 1 % to 30%, in particular from 2% to 20%, more particularly from 5% to 18% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it has an elongation from 4.5% to 40%, in particular 6% to 40%, more particularly from 8% to 30%, even more particularly from 10% to 20%.

[0026] It is now referred to Figure 1 .

[0027] More particularly, it is proposed a filter comprising a nonwoven substrate as filter media, said nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99%, in particular from 80% to 98%, more particularly from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 1 % to 30%, in particular from 2% to 20%, more particularly from 5% to 18% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it presents a spring-back distance D bigger than or equal to 0.6 cm, in particular from 0.8 cm to 1 .5 cm, more particularly from 1 cm to 1 .2 cm, and it has an elongation from 6% to 40%, in particular from 8% to 30%, more particularly from 10% to 20%.

[0028] For the purposes of the present application, “filter” denotes a component that is designed to reduce the amounts of particles and harmful substances, such as tar, that are inhaled by the user of smoking or vaping article. The filter is thus intended to trap and retain particulate matter while allowing the smoke or the aerosol produced by the smoking or vaping article to pass through for inhalation. Typically, the filter has a right circular cylindrical shape and comprises an outer envelope of plug wrap paper and a nonwoven substrate, as filter media, located within this outer envelope.

[0029] For the purposes of the present invention, “spring-back distance” D refers to a measure of the ability of the nonwoven substrate to return to its unfolded state when released after the folding.

[0030] The spring-back distance D can be measured as follows:Spring-back distance D is measured at 22°C and 60%HR on a nonwoven substrate sample having a width of 31 mm and a length of from 290 to 300 mm. The nonwoven substrate sample is conditioned during 24 hours at 22°C and 60%HR before measurements. The nonwoven substrate sample is placed on a horizontal support H, then folded at 180° to create a two-layer nonwoven substrate, both layers LS1 , LS2 of this two-layer nonwoven substrate having the same surface. Then, for 60 seconds, a 51 g weight having a parallelepiped shape with a height of 11 mm and a base of 31 mm x 19 mm is placed on the fold F. The biggest vertical distance between the two layers is then measured after 30 minutes of recovery as the spring- back distance D.

[0031] For the purposes of the present application, “elongation” refers to the percentage increase in length that the nonwoven substrate can undergo before it reaches its breaking point.

[0032] The elongation can be measured according to ISO 1924-2:2008.

[0033] For the purposes of the present application, "binder" denotes a compound having properties enabling consolidation of the nonwoven substrate.

[0034] Typically, the binder may have a glass transition temperature (Tg) higher than or equal to -20°C, in particular from -20°C to 45°C, more particularly from -15°C to 36°C, even more particularly from -10°C to 20°C.

[0035] Unexpectedly, a binder having a Tg in such ranges enables the nonwoven substrate of the filter of the present invention to present the requested elongation, in particular the requested combination of spring-back distance D and elongation so that the nonwoven substrate of the filter of the invention can be folded in festooned bales.

[0036] Without wishing to be bound by any theory, the inventors are of the opinion that the crystallinity of a binder having a glass transition temperature in these rangesis low enough to enable the nonwoven substrate of the filter of the invention to have the elongation, in particular the requested combination of the spring-back distance D and the elongation, adapted to be folded, without cracking, in festooned bales.

[0037] Typically, the binder can be chosen from starch, copolymers and polymers comprising ethylene, vinyl acetate, butadiene, styrene, vinyl chloride, acrylic esters, urethanes, and mixtures thereof, in particular from starch, copolymers and polymers comprising ethylene, vinyl acetate, more particularly from starch and copolymers of ethylene and vinyl acetate.

[0038] According to one particular embodiment, the binder has a glass transition temperature higher than or equal to -20°C and is a copolymer of ethylene and vinyl acetate or starch.

[0039] According to one particular embodiment, the binder has a glass transition temperature from -10°C to 20°C and is a copolymer of ethylene and vinyl acetate.

[0040] The copolymer of ethylene and vinyl acetate is also known as ethylene-vinyl acetate (EVA) and poly(ethylene-vinyl acetate) (PEVA).

[0041] For the purposes of the present application, "nonwoven substrate" denotes a manufactured sheet consisting of a web or ply of directionally or randomly oriented fibers bonded together by friction and / or cohesion and / or adhesion.

[0042] For the purposes of the present application, the term "natural fiber" denotes a fiber of natural origin which has optionally undergone a chemical treatment, a physical treatment, or both, in order to improve the physical characteristics thereof.

[0043] For example, the natural fibers can be chosen from wood fibers, leaf fibers, fruit fibers, seed fibers, bast fibers, stalk fibers, reed fibers, and mixtures thereof, in particular from wood fibers, leaf fibers, seed fibers, bast fibers, and mixtures thereof, more particularly from wood fibers, bast fibers and mixtures thereof.

[0044] Examples of wood fibers which may be present in the nonwoven substrate of the filter of the invention can be hardwood pulp, bleached hardwood pulp, softwood pulp, bleached softwood pulp, softwood fluff pulp, bleached 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 across 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 its precipitation 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), and mixtures thereof, in particular hardwood pulp, softwood pulp, softwood fluff pulp, lyocell fibers, viscose fibers, and mixtures thereof, more particularly softwood pulp, softwood fluff pulp, lyocell fibers, and mixtures thereof.

[0045] For the purposes of the present application, "bast fiber" denotes a plant fiber contained in the bast of the plants.

[0046] As bast fiber, mention may be made of 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, and mixtures thereof, in particular hemp fiber, flax fiber, and a mixture thereof, more particularly flax fiber.

[0047] Typically, the bast fibers may have undergone prior treatment. Thus, the bast fibers may be cottonized bast fibers, individualized bast fibers, bast fibers which have undergone retting, bleached bast fibers, and mixtures thereof, in particular cottonized bast fibers, individualized bast fibers and a mixture thereof.

[0048] For the purposes of the present application, "seed fiber" denotes a fiber obtained from seeds of a plant. Examples of seed fibers can be cotton fiber, kapok fiber, luffa fiber, milkweed fiber, and mixtures thereof, in particular kapok fiber.

[0049] According to one particular embodiment, the natural fibers are chosen from softwood pulp, softwood fluff pulp, flax fiber, lyocell fiber and mixtures thereof, in particular softwood fluff pulp, flax fiber, lyocell fiber and mixtures thereof, more particularly softwood fluff pulp, or cottonized flax fibers.

[0050] The natural fibers may have a length of from 1 mm to 10 mm, in particular from 1 .5 mm to 8 mm, very particularly from 2 mm to 5 mm.

[0051] An airlaid process is particularly suitable for these sizes of natural fibers. Thus, the nonwoven substrate of the filter of the invention can be obtained by an airlaid process.

[0052] The natural fibers may have a length of from 10 mm to 150 mm, in particular from 15 mm to 100 mm, very particularly from 20 mm to 60 mm.

[0053] A drylaid process is particularly suitable for these sizes of natural fibers. Thus, the nonwoven substrate of the filter of the invention can be obtained by a drylaid process.

[0054] The length of the natural fibers can be measured by microscopic measurement using a projection microscope by means of the necessary magnification.

[0055] The natural fibers may also be cut so as to have a length within the ranges mentioned above. Conventional cutting techniques which can be used are guillotine cutting of natural fibers, grinding of the natural fibers with or without a system for removing excessively short and excessively long fibers of air cyclone or screen type.

[0056] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, and the elongation is from 4.5% to 16%.

[0057] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, the elongation is from 4.5% to 16%, and the binder has a Tg higher than or equal to -20°C

[0058] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, the elongation is from 4.5% to 16%, and the binder has a Tg from -10°C to 20°C.

[0059] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, the elongation is from 4.5% to 16%, the natural fibers are softwood fluff pulp, cottonized flax fibers, lyocell fibers, or mixtures thereof, and the binder has a Tg higher than or equal to -20°C.

[0060] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, the elongation is from 4.5% to 16%, the natural fibers are softwood fluff pulp, cottonized flax fibers, lyocell fibers, or mixtures thereof, and the binder is a copolymer of ethylene and vinyl acetate having a Tg from -10°C to 20°C.

[0061] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in whichthe natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, the elongation is from 4.5% to 16%, the natural fibers are softwood fluff pulp, cottonized flax fibers, lyocell fibers, or mixtures thereof, and the binder is starch and has a Tg higher than or equal to -20°C.

[0062] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, the spring-back distance D is from 1 cm to 1 .2 cm, and the elongation is from 10% to 16%.

[0063] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate, the spring-back distance D is from 1 cm to 1 .2 cm the elongation is from 10% to 16%, and the binder has a Tg from -10°C to 20°C.

[0064] According to one particular embodiment, the nonwoven substrate of the filter of the invention comprises natural fibers and a binder, in which the natural fibers represent from 82% to 95% by weight of solids of said nonwoven substrate, the binder represents from 5% to 18% by weight of solids of said nonwoven substrate,the spring-back distance D is from 1 cm to 1 .2 cm, the elongation is from 10% to 16%, the natural fibers are softwood fluff pulp, cottonized flax fibers, lyocell fibers, or mixtures thereof, and the binder is a copolymer of ethylene and vinyl acetate having a Tg from -10°C to 20°C.

[0065] The filter of the present invention may be a filter for a smoking or vaping article.

[0066] 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.

[0067] 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 nonwoven substrate of the filter of the invention as defined above located within the outer envelope.

[0068] 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.

[0069] 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 nonwoven substrate of the filter of the invention as defined above located within the outer envelope.

[0070] According to another aspect, the present invention also relates to a smoking article comprising the filter of the present invention as defined above.

[0071] According to another aspect, the present invention also relates to a vaping article comprising the filter of the present invention as defined above.

[0072] According to another aspect, the present invention relates to a nonwoven substrate.

[0073] This nonwoven substrate is as defined above in relation with the filter of the present invention.

[0074] The present invention also relates to a festooned bale made of a nonwoven substrate as defined above in relation with the filter of the present invention.

[0075] Festooned bale is a type of package commonly used in the packaging of paper substrate, such as nonwoven substrate. Specifically, a continuous ribbon of the nonwoven substrate is laid down in a back-and-forth manner, then compressed into the festooned bale, said festooned bale being for example packaged in a cubic package.

[0076] The present invention also relates to a process for producing the filter, in particular the filter for a smoking or vaping article, of the present invention as defined above, said process comprising the following steps: a) forming a rod of nonwoven substrate from a festooned bale made of a nonwoven substrate, b) wrapping the rod of nonwoven substrate with a sheet of plug wrap paper, c) depositing an adhesive line and joining the sheet of plug wrap paper to obtain a rod of filtering material, d) cutting the rod of filtering material to produce the filter.

[0077] The festooned bale is as described above in relation to the festooned bale of the present invention. The nonwoven substrate is as described above in relation to the filter of the present invention

[0078] This process is advantageously easy to implement since all the steps b) to d) are well-known by the skilled person and the festooned bale does not require to modify step a) which is also well-known by the skilled person. Accordingly, the skilled person will easily know how to adapt the parameters of said steps to produce the filter.

[0079] The present invention also relates to a process for producing a nonwoven substrate as defined above comprising the following steps:i) producing a web from natural fibers by an airlaid process or a drylaid process, in particular an airlaid process, ii) introducing the binder into the web, and iii) drying the web resulting from step ii) to obtain the nonwoven substrate.

[0080] The nonwoven substrate, the natural fibers and the binder are as described above in relation to the filter and the nonwoven substrate of the present invention.

[0081] The airlaid process and the drylaid process are two different conventional routes known to the person skilled in the art to produce a web. The person skilled in the art will know how to adapt the parameters of the airlaid process or the drylaid process to produce the nonwoven substrate of the invention.

[0082] During the step ii), an aqueous dispersion of the binder may be introduced into the web. This introduction may for example be carried out by impregnation, such as impregnation with a size press, by spraying, such as spraying using a spray, by surface application, such as surface application by coating or by printing, in particular by spraying using a spray. Advantageously, the spraying may be performed on both faces of the web.

[0083] The aqueous dispersion of the binder can be obtained by any technique known to the person skilled in the art. The person skilled in the art will know how to adapt the concentration of binder in the aqueous dispersion to obtain the desired content of binder in the nonwoven substrate obtained in step iii).

[0084] Drying step iii) can, for example, be carried out by a drying device, such as a tunnel through which air passes or an infrared ramp.

[0085] This drying step iii) can be carried out at a temperature of between 75°C and 220°C, in particular between 90°C and 220°C, more particularly between 180°C and 210°C. A temperature within these ranges advantageously makes it possible to minimize the duration of this drying step iii) while at the same time minimizing the deterioration of the natural fibers of the nonwoven substrate, thus optimizing the process of the invention.

[0086] Advantageously, the combination of the introduction step ii) and of the drying step iii) makes it possible to improve the cohesion of the natural fibers and hence to consolidate the structure of the nonwoven substrate of the filter of the invention.

[0087] The natural fibers used in production step i) can be a mixture of natural fibers. This mixture of natural fibers can be obtained before production step i).

[0088] The process of the invention can comprise, before production step i), a step i1 ) of cutting the natural fibers to obtain natural fibers having a length within the ranges mentioned above.

[0089] Cutting step i1 ) can be carried out by conventional techniques such as guillotine cutting, grinding of the natural fibers with or without a system for removing excessively short and excessively long fibers of air cyclone or screen type.

[0090] The process may also comprise, between production step i) and introduction step ii), a step ii1 ) of compacting and / or embossing the web to obtain a compacted and / or embossed web, this compacted and / or embossed web then undergoing introduction step ii).

[0091] This compacting step ii1 ) can make it possible to reduce the thickness of the web in order to reach the targeted density of the nonwoven substrate.

[0092] Optionally, the nonwoven substrate obtained at step iii) may be calendered.

[0093] The nonwoven substrate obtained at step iii) may be involved in step a) of the process for producing the filter of the present invention.

[0094] According to an embodiment, the invention relates to a process for producing the festooned bale as defined above, said process comprising the following step: a’) festooning the nonwoven substrate of the invention to produce the festooned bale.

[0095] This process for producing a festooned bale is advantageously easy to implement since the step a’) is well-known by the skilled person.

[0096] This process for producing a festooned bale can be implemented between the process for producing a nonwoven substrate of the present invention and the process for producing a filter of the present invention.Examples

[0097] Example 1 : Manufacture of nonwoven substrates

[0098] Comparative Example: Nonwoven substrate prepared by airlaid technology and comprising 85% by weight of dry matter of nonwoven substrate of softwood fluff pulp and 15% by weight of dry matter of nonwoven substrate of starch.

[0099] The softwood fluff pulp was defibrated into individual fibers and deposited on a forming fabric aerodynamically to obtain a web. A solution comprising 7% by weight of dry matter of starch (Stabilys A053 manufactured by Roquette) is sprayed on both sides of the web. The sprayed web is then dried by hot air oven at a temperature of 200°C.

[0100] The properties of the nonwoven substrate are presented in Table 1 below.

[0101] Example 1.1: Nonwoven substrate prepared by airlaid technology and comprising 83% by weight of dry matter of nonwoven substrate of softwood fluff pulp and 17% by weight of dry matter of nonwoven substrate of a binder being a copolymer of ethylene and vinyl acetate.

[0102] The softwood fluff pulp was defibrated into individual fibers and deposited on a forming fabric aerodynamically to obtain a web. A solution comprising 15% by weight of dry matter of a copolymer of ethylene and vinyl acetate (Vinnapas 192 manufactured by Wacker) is sprayed on both sides of the web. The sprayed web is then dried by hot air oven at a temperature of 180°C.

[0103] The properties of the nonwoven substrate are presented in Table 1 below.

[0104] Example 1.2: Nonwoven substrate prepared by airlaid technology and comprising 85% by weight of dry matter of nonwoven substrate of softwood fluff pulp and 15% by weight of dry matter of nonwoven substrate of a binder being a copolymer of ethylene and vinyl acetate.

[0105] The softwood fluff pulp was defibrated into individual fibers and deposited on a forming fabric aerodynamically to obtain a web. A solution comprising a copolymer of ethylene and vinyl acetate is sprayed on both sides of the web. The sprayed web is then dried by hot air oven at a temperature of around 190°C.

[0106] The properties of the nonwoven substrate are presented in Table 1 below.

[0107] Example 1.3: Nonwoven substrate prepared by drylaid technology and comprising 91 % by weight of cottonized flax fibers and lyocell fibers mixture (90% cottonized flax / 10% lyocell by weight of the fiber mixture) and 9% by weight of a binder being a copolymer of ethylene and vinyl acetate.

[0108] The cottonized linen fibers (VERVAEKE FIBER NV, 22 mm in length) and the lyocell fibers (1.7 dtex I 38 mm in length from Lenzing) were mixed and parallelized with a front card and then deposited on forming fabric. A solution comprising 4% by weight of dry matter of a copolymer of ethylene and vinyl acetate (©Vinamul Elite 15 made by Celanese) is sprayed on both sides of the web. The sprayed web is then dried in a hot air oven at a temperature between 100°C and 120°C.

[0109] The properties of the nonwoven substrate are presented in Table 1 below.

[0110] Example 1.4: Nonwoven substrate prepared by airlaid technology and comprising 89% by weight of dry matter of nonwoven substrate of softwood fluff pulp and 11 % by weight of dry matter of nonwoven substrate of starch.

[0111] The softwood fluff pulp was defibrated into individual fibers and deposited on a forming fabric aerodynamically to obtain a web. A solution comprising 7% by weight of dry matter of starch (Perfectafilm B2115 manufactured by Avebe) is sprayed on both sides of the web. The sprayed web is then dried by hot air oven at a temperature of 200°C.

[0112] The properties of the nonwoven substrate are presented in Table 1 below.

[0113] Example 2: Properties of the substrates manufactured in example 1.

[0114] Spring-back distance D measurements were performed on the substrates by the method described above, at 22°C and 60%HR. Substrates were conditioned during 24 hours at 22°C and 60%HR before measurements. The results of spring- back distance D measurements are presented in Table 1 below.

[0115] The elongation measurements were performed on the substrates according to ISO 1924-2:2008 method, adapted to be performed with 30 mm width specimensat 10 mm / min elongation gradient (speed of jaw separation). The results of elongation measurements are presented in Table 1 below.

[0116] Festooned bales were manufactured from the substrates. As evidenced in Table 1 , it is not possible to produce festooned bale with the nonwoven substrate of the comparative example, whereas it is possible to produce festooned bale with the nonwoven substrates of examples 1.1 , 1.2, 1.3 and 1 .4.

[0117] It is thus shown that the high elongation, in particular the combination of the high elongation and the high spring-back distance D of the substrates of examples1.1 , 1.2, 1.3 and 1 .4 according to the invention enables the production of festooned bales with good runnability on the festooning line.

[0118] In contradiction, no festooned bale can be produced from the substrate of the comparative example which does not present the high elongation, in particular does not present the combination of the high elongation and the high spring-back distance D.

[0119] Filter manufacturing tests were performed with festooned bales made from the substrates of examples 1.1 , 1.2, 1.3 and 1.4 according to the invention. Filters can be made from the festooned bales made from the substrates of examples 1.1 ,1 .2, 1 .3 and 1 .4 according to the invention with good runnability on the filter making line.0120] Table 1

Claims

Claims

1. A filter comprising a nonwoven substrate as filter media, said nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99 by weight of solids of said nonwoven substrate, the binder represents from 1 % to 30% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it has an elongation from 4.5% to 40%.

2. The filter according to claim 1 , wherein said nonwoven substrate presents a spring-back distance (D) bigger than or equal to 0.6 cm.

3. The filter according to claim 1 or claim 2, wherein the glass transition temperature of the binder is higher than or equal to -20°C.

4. The filter according to any one of claims 1 to 3, wherein the binder is chosen from copolymers and polymers comprising ethylene, vinyl acetate, butadiene, styrene, vinyl chloride, acrylic esters, urethanes, and mixtures thereof.

5. The filter according to claim 4, wherein the binder has a glass transition temperature from -10°C to 20°C and is a copolymer of ethylene and vinyl acetate.

6. The filter according to any one of claim 1 to 5 wherein the natural fibers are chosen from wood fibers, leaf fibers, fruit fibers, seed fibers, bast fibers, stalk fibers, reed fibers, and mixtures thereof.

7. The filter according to claim 6 wherein the wood fibers are chosen from hardwood pulp, bleached hardwood pulp, softwood pulp, bleached softwood pulp, softwood fluff pulp, bleached softwood fluff pulp, lyocell fibers, viscose fibers, and mixtures thereof.

8. The filter according to any one of claim 1 to 7 for a smoking or vaping article.

9. Smoking article comprising a filter as defined in claim 8.

10. Vaping article comprising a filter as defined in claim 8.

11. A nonwoven substrate comprising natural fibers and a binder, in which the natural fibers represent from 70% to 99 by weight of solids of said nonwovensubstrate, the binder represents from 1 % to 30% by weight of solids of said nonwoven substrate, said nonwoven substrate being characterized in that it has an elongation from 4.5% to 40%.

12. The nonwoven substrate according to claim 11 presenting a spring-back distance (D) bigger than or equal to 0.6 cm.

13. A festooned bale made of a nonwoven substrate as defined in claim 11 or claim 12.

14. Process for producing a filter as defined in any one of claims 1 to 8 comprising the following steps: a) forming a rod of nonwoven substrate from a festooned bale made of a nonwoven substrate, b) wrapping the rod of nonwoven substrate with a sheet of plug wrap paper, c) depositing an adhesive line and joining the sheet of plug wrap paper to obtain a rod of filtering material, and d) cutting the rod of filtering material to produce the filter.

15. Process for producing a nonwoven substrate as defined in claim 11 or claim 12 comprising the following steps: i) producing a web from natural fibers by an airlaid process or a drylaid process, ii) introducing the binder into the web, and iii) drying the web resulting from step ii) to obtain the nonwoven substrate.

16. Process for producing a festooned bale as defined in claim 13, said process comprising the following step: a’) festooning a nonwoven substrate as defined in claim 11 or claim 12 to produce the festooned bale.

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