Filter comprising smooth paper for smoking or electronic smoking articles

Abstract

The present invention relates to a paper substrate having a smooth surface, suitable for use in filters for smoking or electronic smoking articles.

Description

Technical Field

[0001] The present invention provides a smooth paper substrate which can be used as a filter for smoking articles or electronic cigarette articles. Prior art

[0002] The filter for smoking articles or electronic cigarette articles is in the shape of a right cylinder, and generally comprises an outer envelope of plug-wrapped paper and a substrate located inside the outer envelope. The filter for smoking articles or electronic cigarette articles can prevent users from inhaling tobacco particles and intercept harmful particulate matter contained in smoke or aerosol, such as tar, by means of the substrate.

[0003] Conventional filters are made of cellulose acetate. The nicotine retention capacity of these conventional filters makes the user's perception of the filtered smoke satisfactory. In addition, the filtered smoke produced by these conventional filters has good organoleptic properties. However, conventional filters degrade very slowly, do not disperse quickly in water, and produce microplastics that accumulate and enter the food chain. This is particularly harmful because the filters are not consumed during the puffing / vaping of smoking articles or electronic cigarette articles, but are often present in the environment. Therefore, conventional filters have a significant impact on the environment.

[0004] In order to limit the impact of conventional filters on the environment, it has been proposed to replace cellulose acetate with paper substrates obtained by a wet-laid web process. Since these paper substrates are biodegradable, they can degrade quickly. However, the retention capacity of filters comprising paper substrates for aerosol particle phases, especially nicotine particle phases, is greater than the retention capacity of conventional filters for particle phases. Therefore, the user's perception of smoke filtered by filters comprising paper substrates may be unsatisfactory. For example, smoke filtered by filters comprising paper substrates may have a very light taste. Therefore, compared with filters made of cellulose acetate, the user experience provided by these paper substrates is not satisfactory.

[0005] Technical issues

[0006] Therefore, there is a need for a filter including a paper substrate whose nicotine retention capacity is closer to the retention capacity of a filter including a cellulose acetate substrate, or even at the same order of magnitude as the retention capacity of a filter including a cellulose acetate substrate, so as to provide a satisfactory user experience.

[0007] The inventors' contribution therefore lies in the discovery that this need can be met by using a smooth paper substrate.

[0008] Overview

[0009] According to one aspect, the present invention provides a paper substrate comprising two sides, wherein the smoothness of one of the two sides, in particular both sides, is greater than or equal to 20s, in particular 20s to 600s, very particularly 30s to 500s, more particularly 40s to 400s, even more particularly 50s to 300s.

[0010] In the filter, the paper substrate of the present invention is used as a filter material. Advantageously, the filtering performance of the filter comprising the paper substrate of the present invention is better than the filtering performance of the filter comprising a conventional paper substrate. In fact, the difference between the nicotine retention capacity of the filter comprising the paper substrate of the present invention and the nicotine retention capacity of a cellulose acetate filter is less than the difference between the nicotine retention capacity of a filter comprising a conventional filter paper substrate and the nicotine retention capacity of a cellulose acetate filter.

[0011] Therefore, the user's perception of smoke filtered by a filter including the paper substrate of the present invention is more satisfactory than the user's perception of smoke filtered by a filter including a conventional paper substrate.

[0012] Without wishing to be bound by any theory, the inventors believe that the filtration performance of a filter comprising a paper substrate of the present invention is better than the filtration performance of a filter comprising a conventional paper substrate because the smoothness of one of the two surfaces, in particular both surfaces, of the paper substrate of the present invention is greater than the smoothness of both surfaces of the conventional paper substrate.

[0013] The smoothness of a paper substrate indicates the number of fibers standing upright or semi-standing upright on the surface of the paper substrate. The inventors adopted a method opposite to the conventional method and obtained unexpected results by increasing the smoothness of one side, especially both sides, of the two sides of the paper substrate of the present invention, i.e., reducing the number of fibers standing upright or semi-standing upright on the surface of the paper substrate of the present invention.

[0014] This is because, in order not to negatively affect the filtering performance of the filter due to the reduction of the air permeability of the paper substrate, the paper substrate of the filter is usually obtained from unrefined fibers, so the smoothness of the surface of the traditional paper substrate is relatively low, that is, less than 10s.

[0015] Furthermore, in contrast to cellulose acetate filters, the paper substrate of the invention, due to its composition, can degrade very quickly in the environment. This is particularly advantageous since the environmental impact of a filter comprising a paper substrate according to the invention is less than that of a cellulose acetate filter.

[0016] According to another aspect, the present invention provides a method for producing the paper substrate of the present invention, comprising the following steps:

[0017] a) producing a matte paper substrate by a wet-laid process,

[0018] b) subjecting the matte paper substrate produced in step a) to a smoothing treatment to produce a paper substrate,

[0019] Therein, the smoothing step b) is carried out by calendering, flint polishing or a combination thereof, in particular by calendering.

[0020] Implementation Description

[0021] According to one aspect, the present invention provides a paper substrate comprising two sides, wherein the smoothness of one of the two sides, in particular both sides, is greater than or equal to 20s, in particular 20s to 600s, very particularly 30s to 500s, more particularly 40s to 400s, even more particularly 50s to 300s.

[0022] For the purposes of this application, "paper substrate" refers to a sheet consisting of cellulose fibers obtained by a wet-laid process and comprising two faces, namely the front side and the back side. Substrates obtained by a dry-laid process or an air-laid process do not belong to paper substrates within the meaning of this application.

[0023] For the purposes of the present invention, "smoothness" refers to the time (in seconds) required to draw a certain amount of air at atmospheric pressure between the face of a paper substrate test sample and the annular plane under defined contact conditions at a defined pressure difference. The higher the smoothness of a face of a paper substrate, the smoother the face of the paper substrate. The smoothness of one or both faces of a paper substrate can be determined via the ISO 5627:1995 standard.

[0024] The cellulosic fibres of the paper substrate present in the paper substrate of the present invention may be selected from hardwood pulp, bleached hardwood pulp, softwood pulp, bleached softwood pulp, softwood fluff pulp, hemp fibre, Indian hemp fibre, jute fibre, kenaffibre fibre, kudzu fibre, coin vine fibre, flax fibre, okra fibre, nettle fibre, papyrus fibre, ramie fibre, sisal fibre, esparto fibre cellulose fibres), lyocell fibres (cellulose fibres ground and dissolved in N-methylmorpholine N-oxide monohydrate in order to obtain fibres with variable cross-sectional shapes (circular, oval, cross, annular, lamellar cross-section) and with calibrated length and mass per unit length (which can be selected by a person skilled in the art as required)), viscose fibres (fibres obtained by dissolving cellulose by modifying the hydroxyl groups of cellulose with carbon disulfide (CS2) and then precipitating it in the presence of sulfuric acid (H2SO4), with variable cross-sectional shapes (circular, oval, cross, annular, lamellar cross-section) and with calibrated length and mass per unit length, which can be selected by a person skilled in the art as required), and mixtures thereof, in particular hardwood pulp, softwood pulp and mixtures thereof, more in particular softwood pulp.

[0025] The average length of the cellulose fibers of the paper substrate may be from 1 mm to 3.5 mm, in particular from 1.5 mm to 3 mm, more in particular from 2 mm to 2.7 mm.

[0026] The average length of cellulose fibers can be measured via the ISO 16065-2:2014 method.

[0027] The air permeability of the paper substrate of the present invention can be 0.5 cm 3 ·min -1 cm -2 Up to 2000cm 3 ·min -1 cm -2 , especially 10cm 3 ·min -1 cm -2 Up to 1000cm 3 ·min -1 cm -2 , especially 50cm 3 ·min -1 cm -2 Up to 700cm 3 ·min -1 cm -2 , more particularly greater than 50 cm 3 ·min -1 cm -2 And less than 500cm 3 ·min -1 cm -2 .

[0028] The air permeability of the paper substrate of the present invention depends on the air permeability of the matte paper substrate used to produce the paper substrate of the present invention.

[0029] Therefore, in some cases, the air permeability of the paper substrate of the present invention can be 700 cm 3 ·min -1 cm -2 Up to 1500cm 3 ·min -1 cm -2 .

[0030] Advantageously, the nicotine retention capacity of a paper substrate having an air permeability in the above range is even closer to that of a cellulose acetate filter than filters including conventional paper substrates.

[0031] For the purpose of this application, "air permeability" refers to the average air flow rate per unit surface area of ​​the paper substrate of the present invention under specific conditions, at unit pressure difference and per unit time. The air permeability is measured according to ISO 2965:2009 standard.

[0032] For example, the grammage of the paper substrate may be 10 g / m 2 Up to 60g / m 2 , especially 15g / m 2 Up to 55g / m 2 , more particularly 20 g / m 2 Up to 50g / m 2 .

[0033] These grammage ranges are the grammage ranges of conventional paper substrates. Therefore, those skilled in the art should know how to easily obtain the paper substrate of the present invention having such grammage.

[0034] Furthermore, these grammage ranges allow the paper substrate of the present invention to be easily adapted to different filters.

[0035] ISO 536:2012 standard can be used to determine the grammage of paper substrates. Prior to measurement, the substrates are conditioned for at least 16 hours at 23°C and 50% relative humidity.

[0036] The paper substrate of the invention can be shaped, in particular it can be crimped, folded or rolled. Such shaping allows the properties of the paper substrate to be modified, thereby modifying the properties of the filter comprising the paper substrate. For example, crimping can allow the density of the paper substrate to be modified, thereby increasing or decreasing the pressure drop of the filter comprising the paper substrate of the invention without changing the weight of the filter. In this way, shaping the paper substrate by known processes such as crimping allows the paper substrate to be easily adapted to different filters.

[0037] The paper substrate of the present invention can be used in filters due to its properties.

[0038] According to another aspect, the present invention relates to a filter, in particular a filter for a smoking article or an electronic smoking article, comprising the paper substrate of the invention as defined above.

[0039] In filters, the paper substrate of the present invention is used as a filter material.

[0040] For the purposes of this application, "smoking article" refers to an article comprising tobacco, any other plant intended to be smoked, or a mixture thereof. For example, a smoking article may be a machine-made cigarette, a hand-rolled cigarette, or a homemade cigarette.

[0041] Typically, the filter for smoking articles is in the shape of a right cylinder and comprises an outer wrapper of plugging paper for smoking articles, especially cigarettes, and the paper substrate of the invention as defined above located within the outer wrapper.

[0042] For the purposes of this application, an "electronic smoking article" is an article comprising tobacco, any other plant or mixture thereof intended to be vaped, which is intended to be inserted into a device that heats the tobacco, plant or mixture thereof without burning the tobacco, plant or mixture, and is capable of delivering an aerosol to the user. For example, the electronic smoking article may be a tobacco stick.

[0043] Typically, the filter for electronic smoking articles is in the shape of a right cylinder, and comprises an outer wrapper of plug-in paper for electronic smoking articles, especially a tobacco rod, and the paper substrate of the present invention defined above located inside the outer wrapper.

[0044] According to another aspect, the invention also relates to a smoking article comprising the filter defined above.

[0045] According to another aspect, the invention also relates to an electronic smoking article comprising the filter defined above.

[0046] The invention also relates to the use of the paper substrate defined above in a filter, in particular in a filter for a smoking article or in a filter for an electronic smoking article.

[0047] The present invention also relates to a process for producing the paper substrate of the invention as defined above, comprising the following steps:

[0048] a) producing a matte paper substrate by a wet-laid process,

[0049] b) subjecting the matte paper substrate produced in step a) to a smoothing treatment to produce a paper substrate,

[0050] Therein, the smoothing step b) is carried out by calendering, flint polishing or a combination thereof, in particular by calendering.

[0051] The wet-laid process for producing paper substrate is a conventional process known to those skilled in the art. Those skilled in the art should know how to adjust the parameters of the process to produce paper substrate.

[0052] For example, the calendering of the smoothing step b) can be carried out using a soft calender, a hard calender, a friction calender, a super calender, a bright calender, a hot calender, a cold calender or a combination thereof.

[0053] The smoothing step b) does not change the grammage of the paper substrate.

[0054] Calendering may depend on calender parameters. Typically, these parameters may be the coating material of the calender rolls, the diameter of the calender rolls, the normal force per unit length applied by the calender rolls to the matte paper substrate, the number of contact lines of the calender rolls with the matte paper substrate, the rotation speed of the calender rolls, the temperature of the calender rolls, and combinations thereof.

[0055] Between step a) and step b), the matte paper substrate may be subjected to a wetting step to obtain a wet paper substrate, which is then used in step b).

[0056] This wetting step is particularly suitable for step b) which is carried out by calendering.

[0057] Advantageously, this wetting step makes it possible to improve the smoothness of one or more of the faces of the paper substrate obtained by the process of the invention. Example

[0058] Example 1: Production of the paper substrate of the present invention

[0059] In all examples, the smoothness was measured according to ISO 5627:1995 using a "Bekk Smoothness Tester" from Messmer Büchel.

[0060] Air permeability is measured according to ISO 2965:2009 standard.

[0061] Example 1.1: Weight 36 g / m 2 Paper substrate

[0062] The wet-laid web process produced a 36 g / m 2 A rough paper substrate comprising softwood pulp fibers having an average length of 2.65 mm.

[0063] The matte paper substrate was divided into three parts.

[0064] The first portion of the matte paper substrate was cold calendered using a laboratory soft calender (Perkins laboratory calender) by applying a nominal force per unit length of 263 N / mm. Three passes through the calender were performed using this nominal force per unit length.

[0065] The weight before and after calendering is 36g / m 2 The physical parameters of the paper substrate are shown in Table 1.

[0066] Example 1.2: Weight 36 g / m 2 Paper substrate

[0067] The second portion of the matte paper substrate of Example 1.1 was hot calendered using an industrial hard calender. One pass through the calender was performed. The nominal force per unit length was adjusted to obtain a paper substrate with the physical parameters shown in Table 1.

[0068] After calendering, the weight is 36g / m 2 The physical parameters of the paper substrate are shown in Table 1.

[0069] Example 1.3: Weight 36 g / m 2 Paper substrate

[0070] The third portion of the matte paper substrate of Example 1.1 was first wet treated and then hot calendered using an Andritz laboratory soft calender at 250° C. by applying a nominal force per unit length of 300 N / mm. This nominal force per unit length was used twice through the calender.

[0071] The weight after calendering is 36g / m 2 The physical parameters of the paper substrate are shown in Table 1.

[0072] Example 1.4: Weight 36 g / m 2 Paper substrate

[0073] The wet-laid web process produced a 36 g / m 2 A rough paper substrate comprising softwood pulp fibers having an average length of 2.65 mm.

[0074] The matte paper substrate was then hot calendered using an industrial hard calender. The calender was repeated twice. The nominal force per unit length was adjusted to obtain a paper substrate with the physical parameters shown in Table 1.

[0075] The weight before and after calendering is 36g / m 2 The physical parameters of the paper substrate are shown in Table 1.

[0076] Example 1.5: Weight 50g / m 2 Paper substrate

[0077] The wet-laid web process produced a 50 g / m 2 A rough paper substrate comprising softwood pulp fibers having an average length of 2.65 mm.

[0078] The matte paper substrate was then cold calendered using a laboratory soft calender (Perkins laboratory calender) by applying a nominal force per unit length of 263 N / mm. Three passes through the calender were performed using this nominal force per unit length.

[0079] The weight before and after calendering is 50g / m 2 The physical parameters of the paper substrate are shown in Table 1 below.

[0080] Example 2: Nicotine retention test of a filter comprising the paper substrate of Example 1 and a commercial cellulose acetate filter

[0081] Filters for smoking articles were made by standard methods of making filters using the paper substrate of Example 1. A plug of filter material was wrapped with non-porous plug wrap.

[0082] All filters have the same volume but different weights. This difference is related to calendering, which reduces the filling power of the paper substrate of the present invention. In order to produce filters and cigarettes with the same order of magnitude of pressure drop, more paper substrate of the present invention must be used, which increases the weight of the filter.

[0083] Cigarettes were prepared using the above filters. To form the cigarettes, tobacco rods were assembled with the filters using tipping paper. Commercial "American blend" tobacco was used to form the tobacco rods. The cigarettes were not ventilated.

[0084] The prepared cigarettes were smoked on a Borgwaldt RM20 smoking machine according to ISO 3308:2000. The pressure drop ("PD" in Table 2) was measured according to ISO 6565:2002.

[0085] The filter retention rate is calculated according to the following formula:

[0086]

[0087] in

[0088] CNWF is the amount of nicotine in the smoke (in mg) without a filter, and

[0089] CNAF is the amount of nicotine in the smoke after it has been filtered through the filter (in mg).

[0090] The filter's delivery rate refers to the amount of nicotine in the smoke after it is filtered.

[0091] The nicotine content in the smoke after filtering is determined as follows:

[0092] According to ISO 10315:2000, the nicotine content of smoke produced by 10 smoked cigarettes is measured. This nicotine content is then divided by 10 to calculate the nicotine content of smoke produced by one smoked cigarette.

[0093] This measurement is performed three times, ie using 30 cigarettes, to calculate the nicotine content in the smoke produced by three smoked cigarettes.

[0094] The nicotine content of the smoke after the filter is the average of the nicotine content of the smoke produced by 3 calculated cigarettes smoked.

[0095] In the absence of a filter, the nicotine content of the smoke is determined as follows:

[0096] Tobacco rods identical to those used to make cigarettes were smoked on a Borgwaldt RM20 smoking machine according to ISO 3308:2000. The tobacco rods were smoked the same number of times as cigarettes.

[0097] The nicotine content of the smoke produced by 10 smoked tobacco rods was measured according to ISO 10315:2000. This nicotine content was then divided by 10 to calculate the nicotine content of the smoke produced by one smoked tobacco rod.

[0098] This measurement was carried out three times, ie using 30 tobacco rods, in order to calculate the nicotine content of the smoke produced by three individually smoked tobacco rods.

[0099] The nicotine content of the smoke without filter is the average of 3 calculated nicotine contents of the smoke from one smoking tobacco rod.

[0100] The retention and delivery rates of each filter including the paper substrate of Example 1 were compared to the retention rates of commercial cellulose acetate filters.

[0101] Table 2 shows the "delta retention" and "delta delivery" of the filter including the paper substrate of Example 1.

[0102] The "delta retention" value is the difference between the retention of a filter comprising the paper substrate of Example 1 and the retention of a commercial cellulose acetate filter.

[0103] The "delta delivery rate" value is calculated according to the following formula:

[0104]

[0105] in

[0106] CNAF1 is the nicotine content (in mg) in smoke after filtering through a filter comprising the paper substrate of Example 1, and

[0107] CNACAF is the nicotine content (in mg) in smoke after filtering through a commercial cellulose acetate filter.

[0108] The aspiration results are shown in Table 2 below.

[0109] As shown in Table 2, for the same gram weight:

[0110] The nicotine retention of commercial cellulose acetate filters is closer to the nicotine retention of filters comprising the paper substrate of the present invention than the nicotine retention of filters comprising a matte paper substrate, and

[0111] The nicotine delivery rate of commercial cellulose acetate filters is closer to the nicotine delivery rate of filters comprising the paper substrate of the present invention than the nicotine delivery rate of filters comprising a matte paper substrate.

[0112]

[0113]

Claims

1. A paper substrate comprising two sides, wherein the smoothness of one of the two sides is greater than or equal to 20s.

2. The paper substrate according to claim 1, wherein the smoothness of both surfaces is greater than or equal to 20s.

3. The paper substrate according to claim 1 or 2, having an air permeability of 0.5 cm 3 ·min -1 cm -2 Up to 2000cm 3 ·min -1 cm -2 .

4. The paper substrate according to any one of claims 1 to 3, having a grammage of 10 g / m 2 Up to 60g / m 2 .

5. The paper substrate according to any one of claims 1 to 4, wherein the cellulose fibers of the paper substrate are selected from the group consisting of hardwood pulp, bleached hardwood pulp, softwood pulp, bleached softwood pulp, softwood fluff pulp, hemp fiber, Indian hemp fiber, jute fiber, kenaf fiber, kudzu fiber, money vine fiber, flax fiber, okra fiber, nettle fiber, papyrus fiber, ramie fiber, sisal fiber, needle grass fiber, lyocell fiber, viscose fiber and mixtures thereof.

6. The paper substrate according to any one of claims 1 to 5, wherein the length of the cellulose fibers of the paper substrate is from 1 mm to 3.5 mm.

7. A filter comprising the paper substrate defined in any one of claims 1 to 6 as a filter material.

8. A smoking article comprising a filter as defined in claim 7.

9. An electronic smoking article comprising the filter defined in claim 7.

10. A method for producing a paper substrate as defined in any one of claims 1 to 6, comprising the steps of: a) producing a matte paper substrate by a wet-laid process, b) subjecting the matte paper substrate produced in step a) to a smoothing treatment to produce the paper substrate, Therein, the smoothing step b) is carried out by calendering, flint polishing and combinations thereof.

11. The method according to claim 10, wherein the calendering of the smoothing step b) can be carried out using a soft calender, a hard calender, a friction calender, a super calender, a bright calender, a hot calender, a cold calender or a combination thereof.

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