阅读说明：本技术 具有生物可降解过滤材料的气溶胶生成制品 (Aerosol-generating article with biodegradable filter material ) 是由 T·乔伊柯斯 李平 S·帕帕基里罗 于 2019-12-05 设计创作，主要内容包括：提供了一种气溶胶生成制品(10),其包括气溶胶生成基材(12)和与所述气溶胶生成基材(12)轴向对准的过滤嘴(14)。所述过滤嘴(14)包括由纤维状类纸材料的一个或多个片材形成的至少一个过滤材料段。所述纤维状类纸材料包括疏水性纤维和亲水性纤维的组合,使得所述纤维纸状材料的按照TAPPI/ANSI T 558om-15所测量的水接触角大于90度。进一步地,所述纤维状类纸材料在水性介质中的按照ISO 14851(2005)所测试的生物降解性为纤维素参考物品在56天的测试内的最大降解的至少90％。另外,所述疏水性纤维包括疏水性粘胶纤维。(An aerosol-generating article (10) is provided comprising an aerosol-generating substrate (12) and a filter (14) in axial alignment with the aerosol-generating substrate (12). The filter (14) comprises at least one length of filter material formed from one or more sheets of fibrous paper-like material. The fibrous paper-like material comprises a combination of hydrophobic fibers and hydrophilic fibers such that the fibrous paper-like material has a water contact angle greater than 90 degrees as measured by TAPPI/ANSI T558 om-15. Further, the biodegradability of the fibrous paper-like material in aqueous medium, as tested according to ISO 14851(2005), is at least 90% of the maximum degradation of the cellulose reference article within a 56-day test. Additionally, the hydrophobic fibers include hydrophobic viscose fibers.)

1. An aerosol-generating article, comprising:

an aerosol-generating substrate;

a filter axially aligned with the aerosol-generating substrate, the filter comprising at least one segment of filter material formed from one or more sheets of fibrous paper-like material, wherein the fibrous paper-like material comprises a combination of hydrophobic fibers and hydrophilic fibers such that the fibrous paper-like material has a water contact angle greater than 90 degrees as measured by TAPPI/ANSI T558 om-15, and wherein the biodegradability of the fibrous paper-like material in aqueous media as measured by ISO 14851(2005) is at least 70% of the degradation of a cellulose reference within a 56 day test, wherein the hydrophobic fibers comprise hydrophobic viscose fibers.

2. An aerosol-generating article according to claim 1, wherein the fibrous paper-like material has a water contact angle of between 95 degrees and 105 degrees as measured by TAPPI/ANSI T558 om-15.

3. An aerosol-generating article according to claim 1 or 2, wherein the biodegradability of the fibrous paper-like material in aqueous medium, as tested according to ISO 14851(2005), is at least 90% of the degradation of a cellulose reference within a 56 day test.

4. An aerosol-generating article according to any preceding claim, wherein the fibrous paper-like material has a water absorption of greater than 180 seconds.

5. An aerosol-generating article according to any preceding claim, wherein the hydrophilic fibres and the hydrophobic fibres represent at least 50% by weight of dry matter of the fibrous paper-like material.

6. An aerosol-generating article according to any preceding claim, wherein the ratio of the hydrophobic fibres to the hydrophilic fibres is between 2:3 and 3:2 or between 2:1 and 1: 2.

7. An aerosol-generating article according to claim 6, wherein the ratio of hydrophobic fibres to hydrophilic fibres in the fibrous paper-like material is about 1: 1.

8. An aerosol-generating article according to any preceding claim, wherein the hydrophilic fibres comprise plant fibres, softwood fibres or cellulosic fibres.

9. An aerosol-generating article according to any preceding claim, wherein the fibrous paper-like material has a basis weight of at least 25 grams per square meter.

10. An aerosol-generating article according to any preceding claim, wherein the length of filter material is formed from one or more gathered sheets of the fibrous paper-like material.

11. An aerosol-generating article according to any preceding claim, wherein the one or more sheets of fibrous paper-like material are crimped.

12. An aerosol-generating article according to any preceding claim, wherein the fibrous paper-like material comprises a binder selected from the group consisting of: polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), polyvinyl acetate (PVA), polyethylene, polypropylene, polyesters, cellulose acetate, cellulose esters, alkyl succinic anhydrides, rosin, acrylic copolymers, modified starches, hydrocolloids, and mixtures thereof.

13. A filter segment for use in an aerosol-generating article comprising a filter material defined by a wrapper, the filter material comprising a sheet of fibrous paper material, wherein the fibrous paper-like material comprises a combination of hydrophobic fibres and hydrophilic fibres, wherein the fibrous paper-like material has a water contact angle of greater than 90 degrees as measured by TAPPI/ANSI T558 om-15 and a biodegradability in aqueous media as tested by ISO 14851(2005) of at least 70% of the degradation of a cellulose reference within a 56 day test, wherein the hydrophobic fibres comprise hydrophobic viscose fibres.

Technical Field

The present invention relates to an aerosol-generating article comprising a filter having at least one segment formed from biodegradable filter material.

Background

Conventional aerosol-generating articles such as filter cigarettes typically comprise a cylindrical rod of tobacco cut filler surrounded by a paper wrapper and a cylindrical filter axially aligned with, most often in end-to-end relationship with, the wrapped tobacco rod. Cylindrical filters typically comprise one or more filter segments of fibrous filter material, such as cellulose acetate tow, defined by a paper filter segment wrapper. Conventionally, the wrapped tobacco rod and filter are joined by a band of tipping wrapper, typically made of an opaque paper material which surrounds the entire length of the filter and the adjacent portion of the wrapped tobacco rod.

Many aerosol-generating articles in which tobacco is heated rather than combusted have also been proposed in the art. In heated aerosol-generating articles, an aerosol is generated by heating an aerosol-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, smoking articles in which an aerosol is generated by electrical heating or by transferring heat from a combustible fuel element or heat source to an aerosol-forming substrate. During smoking, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source and become entrained in the air drawn through the smoking article. As the released compound cools, the compound condenses to form an aerosol that is inhaled by the consumer. Many known heated smoking articles include one or more filter segments of fibrous filter material, such as cellulose acetate.

It is desirable that the filter portion disintegrates as quickly as possible after the aerosol-generating article has been drawn in and discarded. Cellulose acetate, the most commonly used filter material, is not biodegradable, so a wide variety of dispersible and degradable materials have been proposed for use as filter materials in aerosol-generating articles.

However, in many instances, such alternative filter materials have been found to not provide acceptable filtration efficiency and smoking experience for consumers. Furthermore, in many cases it has been found that dispersible and degradable materials are not suitable for use in existing manufacturing processes and would require too much modification to existing methods and equipment to make their use commercially viable.

Accordingly, it would be desirable to provide an aerosol-generating article having a filter formed at least in part from a filtration material having improved biodegradability but providing a filtration efficiency comparable to that of cellulose acetate tow. Furthermore, it would be desirable to provide an aerosol-generating article that provides an acceptable sensory experience for the consumer. In addition, it would be desirable to provide aerosol-generating articles that can be readily manufactured using existing high speed techniques and equipment requiring only minimal modifications.

Disclosure of Invention

According to an aspect of the present invention, there is provided an aerosol-generating article comprising: an aerosol-generating substrate; a filter axially aligned with the aerosol-generating substrate, the filter comprising at least one segment of filter material formed from one or more sheets of fibrous paper-like material, wherein the fibrous paper-like material comprises a combination of hydrophobic fibers and hydrophilic fibers such that the fibrous paper-like material has a water contact angle greater than 90 degrees as measured by TAPPI/ANSI T558 om-15, and wherein the biodegradability of the fibrous paper-like material in aqueous media as measured by ISO-14851(2005) is at least 90% of the maximum degradation of a cellulosic reference article under 56 days of testing.

According to another aspect of the invention, there is provided a filter material for an aerosol-generating article, the filter material comprising a sheet of fibrous paper-like material, wherein the fibrous paper-like material comprises a combination of hydrophobic fibres and hydrophilic fibres such that the fibrous paper-like material has a water contact angle, measured according to TAPPI/ANSI T558 om-15, of greater than 90 degrees, and wherein the fibrous paper-like material has a biodegradability in aqueous medium, measured according to ISO 14851(2005), of at least 90% of the maximum degradation of a cellulosic reference article in a 56 day test.

It will be appreciated that any feature described with reference to one aspect of the invention is equally applicable to any other aspect of the invention.

The term "aerosol-generating article" is used herein to denote both articles, i.e. articles in which the aerosol-generating substrate is heated and articles in which the aerosol-generating substrate is combusted, such as conventional cigarettes. As used herein, the term "aerosol-generating substrate" refers to a substrate capable of releasing volatile compounds upon heating to generate an aerosol.

Traditional smoking is lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to be lit and the resulting combustion produces breathable smoke.

In a heated aerosol-generating article, an aerosol is generated by heating a flavour-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles, as well as aerosol-generating articles in which an aerosol is generated by heat transfer from a combustible fuel element or heat source to a physically separate aerosol-forming material. For example, aerosol-generating articles according to the present invention find particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internal heater blade adapted for insertion into a stem of an aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art (for example in european patent application EP 0822670).

As used herein, the term "aerosol-generating device" refers to a device comprising a heater element which interacts with an aerosol-generating substrate of an aerosol-generating article to generate an aerosol. Aerosol-generating articles according to the invention may comprise a combustible carbon heat source for heating the aerosol-generating substrate during use. Aerosol-generating articles of this type are described in the prior art (e.g. in WO 2009/022232). Aerosol-generating articles are also known in which nicotine-containing aerosols are generated from tobacco material, tobacco extracts or other nicotine sources without combustion and in some cases without heating, for example by chemical reaction. During smoking, volatile compounds are released from the aerosol-forming substrate by heat transfer from the fuel element and entrained in air drawn through the aerosol-generating article. As the released compound cools, the compound condenses to form an aerosol that is inhaled by the consumer.

The term "paper-like" is used herein to denote a material in sheet form such as can be manufactured by methods and equipment known in the papermaking art. In the manufacture of one such material, the fibrous starting material is typically uniformly distributed in an aqueous medium to obtain a diluted suspension. To aid in the distribution of the fibers in the aqueous suspension, dispersants may additionally be used. A mat of randomly interwoven fibers was laid down by draining the suspension through a sieve-like screen. Excess water is typically removed from such mats by pressing, optionally with the aid of a suction or heat source. After the drying step, a generally flat and uniform sheet is achieved.

As used herein, the term "hydrophobic" refers to a material or surface that exhibits water-repellent properties. As will be described in more detail below, one useful way to determine this is to measure the water contact angle. The "water contact angle" is the angle through a liquid as conventionally measured when the liquid/vapor interface encounters a solid surface. This angle quantifies the wettability of the solid surface by the liquid substantially as described by the young's equation.

In contrast, the term "hydrophilic" is used in this specification to denote a material or surface that exhibits a strong affinity for water, for example, a material or surface that exhibits a tendency to mix with, dissolve in, or be wetted by water.

The term "hydrophobic fibers" is used to indicate fibers having hydrophobic properties. In the case of fibers, the hydrophobic properties can also be evaluated by a sink test. In one such test, the time required for the fiber to sink into a predetermined amount of water is measured. For viscose fibres without hydrophobic properties, the sinking time is generally less than 5 seconds. For hydrophobic viscose fibres, the sinking time is generally greater than 24 hours.

Hydrophobic viscose fibres are described, for example, in US 2015/0329707. In more detail, US 2015/0329707 discloses hydrophobic viscose fibres as a resulting mixture of generally viscose fibres and a hydrophobic substance selected from the group consisting of: alkyl ketene dimer, alkenyl ketene dimer, alkyl succinic anhydride, alkenyl succinic anhydride, alkyl glutaric anhydride, alkenyl glutaric anhydride, alkyl isocyanate, alkenyl isocyanate, fatty acid anhydride, and mixtures thereof. The hydrophobic substance is present in an amount of about 0.1% by weight based on the viscose to about 13% by weight based on the viscose, and preferably about 1% by weight based on the viscose to about 7.5% by weight based on the viscose. Examples of suitable hydrophobic viscose fibres are from Kelheim Fibers GmbHViscose fibers.

The term "cellulosic fibers" is used herein to identify bleached or unbleached cellulosic plant fibers obtained by chemical, mechanical or thermomechanical pulping processes, such as softwood fibers, wood pulp, or pulp of annual plants such as, for example, flax or tobacco. Further, the term "cellulosic fiber" may refer to mixtures of two or more of these bleached or unbleached cellulosic plant fibers.

As used herein, the term "longitudinal" refers to a direction corresponding to a major longitudinal axis of an aerosol-generating article extending between an upstream end and a downstream end of the aerosol-generating article. During use, air is drawn through the aerosol-generating article in the longitudinal direction. The term "transverse" refers to a direction perpendicular to the longitudinal axis.

Any reference to a "cross-section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross-section, unless otherwise specified. As used herein, the term "length" refers to the dimension of a component in the longitudinal direction, and the term "width" refers to the dimension of a component in the transverse direction. The term "maximum width" refers to the largest cross-sectional dimension of a component. For example, in the case of a segment with a circular cross section, the maximum width corresponds to the diameter of a circle.

The term "width" when used with respect to a strand or rod that is cut or shredded from a sheet material refers to the smaller dimension of the strand or rod when laid flat, regardless of the spatial orientation of the strand or rod within the aerosol-generating article. The term "length" when used with respect to a rod or rod formed from sheet material refers to the larger dimension of the rod or rod when laid flat, regardless of the spatial orientation of the rod or rod within the aerosol-generating article.

As used herein, the terms "upstream" and "downstream" describe the relative position of segments or elements, or portions of segments or elements, of an aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

An aerosol-generating article according to the present invention comprises an aerosol-generating substrate and a filter in axial alignment with the aerosol-generating substrate. The filter is typically arranged downstream of the aerosol-generating substrate. The filter comprises at least one length of filter material formed from one or more sheets of fibrous paper-like material.

In contrast to existing aerosol-generating articles, the fibrous paper-like material according to the present invention comprises a combination of hydrophobic fibers and hydrophilic fibers such that the fibrous paper-like material has a water contact angle greater than 90 degrees as measured by TAPPI/ANSI T558 om-15. In practice, the ratio of hydrophobic fibers to hydrophilic fibers in the fibrous paper-like material is advantageously balanced such that the sheet of fibrous paper-like material behaves as an overall hydrophobic material, while at the same time maintaining a sufficient amount of hydrophilic fibers to make it possible to form a sheet in a papermaking process.

Further, the biodegradability of the fibrous paper-like material in aqueous medium, as tested according to ISO-14851(2005), is at least 90% of the maximum degradation of the cellulose reference article within a 56-day test. By using biodegradable fibers for the hydrophobic element and the hydrophilic element of the fibrous paper-like material, a high level of biodegradability can be advantageously achieved.

In practice, the filter segments of aerosol-generating articles according to the invention provide a similar balance of hydrophobicity and hydrophilicity as found in the case of conventional cellulose acetate filter segments, but with the advantage of significantly improved biodegradability. The inclusion of hydrophilic fibers enables the formation of paper-like web materials using techniques traditionally used for papermaking, while at the same time the addition of hydrophobic fibers results in the provision of an overall hydrophobic sheet such that properties similar to those of conventional (non-biodegradable) cellulose acetate materials are ultimately obtained. The presence of hydrophobic and hydrophilic fibers in the material can be determined by paper photomicrograph analysis, which is well known in the art. In the sheet of fibrous paper-like material, hydrophilic fibers and hydrophobic fibers represent at least 50%, at least 60%, at least 70% or at least 80% by weight of the dry matter of the fibrous paper-like material.

Thus, the overall sensory experience provided by the filter segment of an aerosol-generating article according to the invention is effectively comparable to that of a conventional cellulose acetate tow filter segment, but with significantly improved environmental impact.

The manufacture of aerosol-generating articles according to the present invention does not require any significant modification to existing equipment and processes. The sheet material can be readily manufactured using conventional paper making techniques and can be formed into filter rods using existing filter making equipment, which makes the use of the material commercially viable. The diagonal process is particularly preferred for forming sheet materials because it facilitates the formation of highly porous and lofty web structures.

As briefly described above, in the aerosol-generating substrate according to the invention, the filter comprises at least one segment of filter material formed from one or more sheets of fibrous paper-like material, wherein the fibrous paper-like material comprises a combination of hydrophobic and hydrophilic fibres. By adjusting the type and amount of hydrophobic fibers incorporated into the fibrous paper-like material, the hydrophobic properties of the material can be controlled.

The hydrophobicity of the fibrous paper-like material is determined according to the test described in TAPPI/ANSI T558 om-15 and can range from near zero degrees to near 180 degrees as a result presented by contact angle measured in degrees. In more detail, a specified deposition parameter is used to apply a specified volume of water droplets to the surface of the fibrous paper-like material according to the test described in TAPPI/ANSI T558 om-15. After deposition, images of the droplets in contact with the sheet are captured by a camera at specified time intervals. The water contact angle, i.e. the angle formed by the sheet of fibrous paper-like material and the tangent to the surface of the water droplet in contact with the sheet, is determined by image analysis techniques on the captured image. The water contact angle, rate of change of contact angle, change in drop height and diameter at a given time can also be analyzed and can provide additional information about the material being tested.

According to the invention, the fibrous paper-like material has a water contact angle of more than 90 degrees. Thus, the sheet of fibrous paper-like material effectively behaves as an overall hydrophobic material.

Preferably, the fibrous paper-like material has a water contact angle greater than 95 degrees. More preferably, the fibrous paper-like material has a water contact angle of greater than 100 degrees.

Additionally, or alternatively, the fibrous paper-like material has a water contact angle of less than 110 degrees. In a preferred embodiment, the fibrous paper-like material has a water contact angle of 80 to 120 degrees. More preferably, the fibrous paper-like material has a water contact angle of 95 to 110 degrees.

In contrast, conventional cellulose acetate and paper (cellulose) sheets all have water contact angles of less than about 40 degrees. In other words, they all behave as bulk hydrophilic materials.

In the aerosol-generating article according to the invention, biodegradable fibers are used to form both the hydrophobic and hydrophilic portions of the fibers of the paper-like material. As briefly described above, the biodegradability of the fibrous paper-like material in aqueous medium is at least 90% of the maximum degradation of the cellulose reference article within a 56 day test.

The aqueous biodegradability properties of fibrous paper-like materials are determined according to the test described in the determination of the final aerobic biodegradability of plastic materials in ISO 14851 aqueous medium-method for measuring oxygen demand in closed respirators (2005). The test material is brought into a liquid medium which is essentially free of other organic carbon sources and which is doped with a chemically defined composition of the microorganisms. During aerobic biodegradation of organic material in an aqueous medium, oxygen is consumed and carbon is converted to gaseous mineral carbon in the form of carbon dioxide. A portion of the organic material is taken up for cell growth. The KOH solution is used to capture the released carbon dioxide and the pressure drop induced thereby is directly related to the oxygen consumed, thus providing an indirect measure of the biodegradation of the test material. The amount of biodegradation based on oxygen consumption is expressed as the ratio of biochemical oxygen demand (BOD, corrected for control) to theoretical oxygen demand (ThOD) or Chemical Oxygen Demand (COD) of the test material. Biodegradation based on carbon dioxide production was calculated as the percentage of solid carbon of the test material that had been converted to gaseous mineral carbon in the form of carbon dioxide.

According to european standard EN 14987 plastic-wastewater treatment plant disposal capacity assessment-final acceptance test protocol and specifications (2006), a material can be said to be biodegradable only if the percentage of biodegradation adds up to at least 90% or 90% of the maximum degradation of a suitable reference article within a 56 day test. In practice, the amount of biodegradation determined for a test material is compared to the amount of biodegradation determined for a cellulose reference article having specified properties.

At the start of the experiment, the reactor was filled with the same amount of mineral medium and a predetermined amount of microbial source (inoculum) to obtain a test medium with the indicated concentration of suspended solids per liter. The cellulose reference article and test material were added to the reactor and the reactor was incubated in the dark at a controlled ambient room temperature for at least 28 days. During the incubation period, oxygen consumption was continuously recorded, however the amount of carbon dioxide produced and captured in the KOH solution was determined by a three-titration method at regular intervals. The test material can be considered biodegradable if the conditions set out above are met.

Preferably, the biodegradability of the fibrous paper-like material in the soil medium, as tested according to IS 17556(2012), IS at least 80% of the maximum degradation of the cellulose reference article within a 120-day test. More preferably, the biodegradability of the fibrous paper-like material in the soil medium, as tested according to IS 17556(2012), IS at least 80% of the maximum degradation of the cellulose reference article within a 90-day test. Even more preferably, the biodegradability of the fibrous paper-like material in the soil medium, as tested according to IS 17556(2012), IS at least 80% of the maximum degradation of the cellulose reference article within a 60 day test.

The aqueous biodegradability properties of fibrous paper-like materials are determined according to ISO 17556 by measuring the amount of oxygen demand or carbon dioxide released in a respirator to determine the final aerobic biodegradability in soil (2012). The test material was mixed with soil and incubated in the dark at ambient room temperature. During biodegradation by microbial activity, a mixture of gas, mainly carbon dioxide and water, is produced. Carbon dioxide is captured in KOH solution and is periodically determined by titration, which allows one to determine cumulative carbon dioxide production. The percent biodegradation can be calculated as the percent of solid carbon of the test material that has been converted to gaseous carbon in the form of carbon dioxide.

In view of the realizationThe biodegradable soil qualification marking of (a), after both the test material and the reference item have reached a plateau, the percentage of biodegradation of the test material needs to add up to at least 90% or 90% of the maximum degradation of the suitable reference item. In practice, at the end of the test lasting 120 days, the amount of biodegradation determined for the test material is compared with that of the test articleThe measured amounts of biodegradation of reference articles of cellulose having the specified properties are compared. The test material can be considered biodegradable if the conditions set out above are met.

In contrast, the biodegradation of conventional cellulose acetate sheet materials in aqueous media is about 20% to 25% of the maximum degradation of the cellulose reference article. On the other hand, cellulose-based materials, such as paper wrappers and tipping papers, commonly used to make filters and other components of aerosol-generating materials, can biodegrade in aqueous media to 90% or more of the maximum degradation of the reference article.

Other properties of the sheet material can also be advantageously controlled by adjusting the ratio of hydrophilic fibers to hydrophobic fibers in the fibrous paper-like material. In general, the presence of hydrophilic fibers is desirable because it aids in forming a sheet of fibrous material in the papermaking process.

Preferably, the fibrous paper material has a water absorption of at least 180 seconds as measured by TAPPI T432 cm-09.

Water-absorbing substrate the water absorption of the fibrous paper-like material of the filter according to the invention was determined according to the test described in TAPPI T432 cm-09. This test procedure determines the time required for an unsized and absorbent paper-like material to completely absorb a specified amount of water. For this purpose, ten samples of fibrous paper-like material, each sample being about 100X100 mm, were conditioned and tested under a controlled atmosphere. The test sample is placed on a horizontal support and a predetermined amount of distilled or deionized water is allowed to flow onto the test sample for a given period of time. A timer is started as soon as the water contacts the sample and the time required to completely absorb the water is measured, as indicated visually by the disappearance of the shiny or shiny areas from the wet spots. The test was repeated for all ten samples and the average absorption time in seconds was taken as the water absorption of the test material.

In contrast, the 100% cellulose paper has a water absorbency of 2 seconds or less as measured by TAPPI T432 cm-09. The water absorption measured as TAPPI T432 cm-09 of cellulose acetate of the type conventionally used in filters for aerosol-generating articles is typically 180 seconds or more. The fibrous paper-like material may comprise from about 10% to about 90% hydrophilic fibers on a dry weight basis and from about 90% to about 10% hydrophobic fibers on a dry weight basis. The hydrophilic fibers and hydrophobic fibers, when taken as a whole, may represent at least 50% of the fibrous paper-like material on a dry weight basis.

Preferably, the fibrous paper-like material comprises at least 40 wt% hydrophobic fibers on a dry weight basis, with the remainder being hydrophilic fibers. More preferably, the fibrous paper-like material comprises at least 45 wt% hydrophobic fibers on a dry weight basis. Even more preferably, the fibrous paper-like material comprises at least 50 wt% hydrophobic fibers on a dry weight basis.

The ratio of hydrophobic to hydrophilic fibers in the fibrous paper-like material can be adjusted to control the hydrophobicity of the sheet or sheets forming the filter. Preferably, the ratio of hydrophobic to hydrophilic fibers in the filter is between about 2:3 and 3: 2. In a particularly preferred embodiment, the ratio of hydrophobic fibers to hydrophilic fibers in the filter is about 1:1, with about 50% hydrophobic fibers and 50% hydrophilic fibers.

The hydrophilic fibers preferably comprise cellulosic fibers. More preferably, the hydrophilic fibers are comprised of cellulose fibers. Suitable alternative hydrophilic fibers include cotton, wool, hydrophilic viscose. Further suitable alternative hydrophilic fibers will be known to the skilled person. As examples, hardwood (eucalyptus, birch, beech), softwood (pine, fir) and non-tree (bamboo) sources can be used. Chemical processes and bleaching can be used to process the wood chips into pulp grade sheet. The fibers may then be formed by processing and dissolving the pulp sheet into a dope and by spinning the dope into fibers. The output of one such process can be in the form of staple fibers (cut and baled) or in the form of filament yarns.

In some embodiments, the hydrophilic fibers comprise refined cellulose fibers. The shepper-Riegler degree (SR degree) of the refined cellulose fiber may be generally 9 to 90 degrees SR, preferably 10 to 40 degrees SR, more preferably 15 to 25 degrees SR. Refined cellulose fibers having SR degrees within the ranges set forth above may advantageously help impart improved tensile strength to the sheet of fibrous paper-like material. SR degree is measured according to ISO 5267-1 (month 7 2000).

Typically the hydrophobic fibres have a diameter of from 0.015 to 0.045 mm, preferably from 0.02 to 0.04 mm.

Typically, the length of the hydrophilic fibers is less than 20 millimeters, preferably from 1 millimeter to 12 millimeters, and even more preferably from 2 millimeters to 5 millimeters. Fibers having lengths within these ranges advantageously make it easier to make sheets of fibrous paper-like material.

The hydrophobic fibers preferably comprise hydrophobic viscose fibers. More preferably, the hydrophobic fibers are comprised of hydrophobic viscose fibers. Suitable alternative hydrophobic fibers will be known to the skilled person and may include polyester fibers and acrylic fibers.

In a particularly preferred embodiment, the fibrous paper-like material is formed from a mixture comprising 50% cellulose fibres and 50% hydrophobic viscose fibres.

Preferably, the titer of the hydrophobic fibers is 0.5dtex to 40 dtex. More preferably, the hydrophobic fibers have a titer of 1dtex to 6 dtex. Even more preferably, the hydrophobic fibers have a titer of 1.7dtex to 3.3 dtex. Additionally, or alternatively, the hydrophobic fibers preferably have a denier of less than about 5 dtex. More preferably, the hydrophobic fibers have a denier of less than about 3 dtex.

Typically, the length of the hydrophobic fibers is less than 20 millimeters, preferably from 1 millimeter to 12 millimeters, and even more preferably from 2 millimeters to 5 millimeters. Fibers having lengths within these ranges advantageously make it easier to make sheets of fibrous paper-like material.

The basis weight of the fibrous paper-like material may be from about 15 grams per square meter to about 60 grams per square meter. In a preferred embodiment, the fibrous paper-like material has a basis weight of at least about 20 grams per square meter. Even more preferably, the fibrous paper-like material has a basis weight of at least 25 grams per square meter. Additionally, or alternatively, the basis weight of the fibrous paper-like material is preferably less than about 50 grams per square meter. More preferably, the fibrous paper-like material has a basis weight of less than about 40 grams per square meter. In particularly preferred embodiments, the sheet basis weight of the fibrous paper-like material is from about 20 grams per square meter to about 50 grams per square meter, more preferably from about 25 grams per square meter to about 40 grams per square meter.

The sheet of fibrous paper-like material may have a thickness of about 0.025 mm to about 0.2 mm. In a preferred embodiment, the sheet of fibrous paper-like material has a thickness of at least about 0.05 mm, more preferably at least 0.07 mm. Additionally, or alternatively, the sheet of fibrous paper-like material preferably has a thickness of less than 0.175 mm, more preferably less than about 0.16 mm. In a particularly preferred embodiment, the sheet of fibrous paper-like material has a thickness of from about 0.05 mm to about 0.175 mm, more preferably from about 0.07 mm to about 0.16 mm.

The sheet of fibrous paper-like material may have a porosity of about 1000 CORESTA units to about 50000 CORESTA units. In a preferred embodiment, the sheet of fibrous paper-like material has a porosity of at least about 5000 CORESTA units, more preferably at least 10000 CORESTA units. In addition, or as an alternative, the porosity of the sheet of fibrous paper-like material is preferably less than 40000 CORESTA units, more preferably less than 35000 CORESTA units. In a particularly preferred embodiment, the sheet of fibrous paper-like material preferably has a porosity of from about 5000 CORESTA units to about 40000 CORESTA units, more preferably from about 10000 CORESTA units to about 35000 CORESTA units. The porosity of the sheet was measured according to IS 2965: 2009.

The sheet of fibrous paper-like material may typically have a tensile strength MD (in the machine direction) of at least about 1500cN/30 mm. Preferably, the sheet of fibrous paper-like material has a tensile strength MD of at least about 2000cN/30 mm, more preferably at least about 2510cN/30 mm. In addition, or as an alternative, the sheet of fibrous paper-like material preferably has a tensile strength MD of less than 3500cN/30 mm, more preferably less than about 3200cN/30 mm. In a particularly preferred embodiment, the sheet of fibrous paper-like material has a tensile strength MD of from about 2000cN/30 mm to about 3500cN/30 mm, more preferably from about 2510cN/30 mm to about 3200cN/30 mm.

The sheet of fibrous paper-like material may typically have a tensile strength CD (in the cross-machine direction) of at least about 100cN/30 mm. Preferably, the sheet of fibrous paper-like material has a tensile strength CD of at least about 500cN/30 mm, more preferably at least about 900cN/30 mm. In addition, or as an alternative, the sheet of fibrous paper-like material preferably has a tensile strength CD of less than 2000cN/30 mm, more preferably less than about 1750cN/30 mm. In a particularly preferred embodiment, the sheet of fibrous paper-like material has a tensile strength CD of from about 500cN/30 mm to about 2000cN/30 mm, more preferably from about 900cN/30 mm to about 1750cN/30 mm.

Tensile strength was measured according to ISO 1924-2 (month 12 2008), with the following exceptions: speeds of 10 mm/min (in MD) and 30 mm/min (in CD) instead of 20 mm/min; the width of the test specimen was 30 mm instead of 15 mm.

In some embodiments, the fibrous paper-like material includes an additive selected from the group consisting of sizing agents, humectants, selective filters, and mixtures thereof.

The sizing agent may be one of an alkyl ketene dimer, an alkenyl succinic anhydride, rosin, and mixtures thereof. The sizing agent may advantageously improve the hydrophobicity, surface strength and printability of the sheet of fibrous paper-like material.

The humectant may be a polyether, such as a polyalkylene glycol having an average molecular weight of at least about 500 g/mole. Other examples of suitable humectants include monopropylene glycol, sorbitol, glycerin, triacetin, and mixtures thereof.

The selective filtering agent may be an amino acid or an amino acid salt, in particular a basic amino acid or a basic amino acid salt, or a combination thereof.

Typically, the fibrous paper-like material comprises less than 45% by dry weight of additives. Preferably, the fibrous paper-like material comprises less than about 30% by weight of additives. The additive may advantageously accelerate the biodegradation kinetics of the fibrous paper-like material.

In some embodiments, the fibrous paper-like material includes a binder. The binding agent may be selected from the group consisting of: polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), polyvinyl acetate (PVA), polyethylene, polypropylene, polyesters, cellulose acetate, cellulose esters, alkyl succinic anhydrides, rosin, acrylic copolymers such as styrene acrylic copolymers, modified starches, hydrocolloids such as gelatin, and mixtures thereof.

In one embodiment, the binder may be in the form of fibers. One such binding agent may be selected from the group consisting of: polyvinyl alcohol (PVOH) fibers, polyvinyl acetate (PVA) fibers, polyethylene fibers, polypropylene fibers, polyester fibers, cellulose acetate fibers, nylon, cellulose ester fibers, and mixtures thereof.

Typically, the fibrous paper-like material may comprise 20% or less binder by dry weight. In a preferred embodiment, the fibrous paper-like material comprises from about 5% by dry weight to 15% by dry weight of the binder.

It has been found that embodiments of the fibrous paper-like material of the present invention that include a binder exhibit improved tensile strength (in both MD and CD). This advantageously further contributes to an improved processability of the fibrous paper-like material of the invention. In addition, the fibrous paper-like material of the present invention generally has a smoother finish, which can result in a reduction in friction.

In a particularly preferred embodiment, the sheet of paper-like fibrous material comprises 37% by dry weight to 39% by dry weight of refined cellulose fibers as hydrophilic fibers, 37% by dry weight to 39% by dry weight of hydrophobic viscose fibers, 7% by dry weight to 8% by dry weight of sizing agent and 15% by dry weight to 18% by dry weight of humectant.

In another particularly preferred embodiment, the sheet of paper-like fibrous material comprises 27% by dry weight to 29% by dry weight of refined cellulose fibers as hydrophilic fibers, 27% by dry weight to 29% by dry weight of hydrophobic viscose fibers, 15% by dry weight to 25% by dry weight of binding agent, 7% by dry weight to 8% by dry weight of sizing agent and 15% by dry weight to 18% by dry weight of humectant.

Conventional paper making processes and equipment can be used to produce sheets of fibrous paper-like material for use in filters for aerosol-generating articles according to the invention from a combination of hydrophobic and hydrophilic fibres as set out above. Thus, the fibers can be brought into an aqueous suspension or slurry that can be converted into paper-like sheets on, for example, a fourdrinier paper machine. The wet sheet of fibrous paper-like material for use in the present invention can be made on a diagonal, flat or cylindrical machine or by other means of papermaking. Preferably a diagonal machine is used. The wet sheet thus formed is then dried to obtain a sheet of fibrous paper-like material.

The drying operation may be typically performed at a temperature of about 60 degrees celsius to about 175 degrees celsius, preferably about 70 degrees celsius to about 150 degrees celsius, even more preferably about 80 degrees celsius to 130 degrees celsius.

If the sheet of paper-like fibrous material contains one or more of the above-mentioned additives, the additives may be added to the aqueous suspension or slurry in the same step of mixing the hydrophobic and hydrophilic fibers with water or after the fiber-containing suspension or slurry has been formed. Alternatively, one or more additives may be added to, for example, the formed wet-type paper sheet prior to the drying operation. In another alternative process, one or more additives may be added to the paper-like sheet after the drying operation has been completed.

Typically, the sizing agent is added to the wet paper using bath sizing, using a sizing press, by sputtering, by using a smoothing press, by using a gate roll sizing press, using calendar sizing, by blade coating, and the like. When a sizing press is used to apply the sizing agent, the newly formed wet paper can be passed through rollers that press the sizing agent into the paper sheet and optionally remove excess additives or sizing agents.

There may be certain advantages to using a sizing press to apply the sizing. For example, sizing agents can make wet paper more hydrophobic or can improve surface strength or water resistance or both. Therefore, the wet paper may be more easily dewatered.

Any suitable technique may be used to apply the humectant to the paper. For example, the wetting agent may be applied by a size press, sputtering, knife coating, meyer rod coating, dusting, transfer roll coater, or by any suitable printing process. Suitable printing processes include offset printing, gravure printing, and the like. In one embodiment, the humectant may cover substantially 100% of the surface area of one or both sides of the sheet of paper-like fibrous material.

In one embodiment, the humectant can be printed on one or both sides of the sheet of paper-like fibrous material. Thus, the humectant serves to coat the paper while still maintaining the benefits. As an example, the humectant may be applied to one surface of the sheet of paper-like fibrous material so as to cover 10% to 100% of the surface area of the sheet of paper-like fibrous material, preferably 20% to 90% of the surface area of the sheet of paper-like fibrous material, more preferably 40% to 60% of the surface area of the sheet of paper-like fibrous material. In an alternative embodiment, or in addition, to increase the reaction area, the humectant can be distributed in the thickness of the sheet of paper-like fibrous material.

The selective filtering agent may, for example, be combined with the sizing agent or wetting agent and applied simultaneously therewith.

As will be explained in more detail below, the drying operation may be followed by another step of shaping the dried sheet by one or more of gathering, curling, embossing, creping. Preferably, the length of filter material is formed from one or more gathered sheets of fibrous paper-like material. More preferably, the gathered sheet or sheets of fibrous paper-like material in the length of filter material is/are defined by a wrapper, such as a conventional (paper) filter plug segment wrapper.

As used herein, the term "gathered" means that the sheet of fibrous paper-like material is crimped, folded, or otherwise compressed or shrunk substantially transverse to the cylindrical axis of the filter segment.

The gathered sheet of fibrous paper-like material preferably extends along substantially the entire length of the filter segment and across substantially the entire transverse cross-sectional area of the filter segment.

Filter segments formed from one or more gathered sheets of fibrous paper-like material according to the present invention may advantageously exhibit a significantly lower weight standard deviation. The weight of a filter segment formed from one or more gathered sheets and having a particular length is determined by the density, width and thickness of the sheets of fibrous paper-like material gathered to form the filter segment. The weight of such filter segments can thus be adjusted by controlling the density and size of the sheets of fibrous paper-like material. This advantageously reduces weight inconsistencies between filter segments according to the invention of the same size and as such results in a reduced rejection rate for filter segments having weights outside the selected acceptance range.

Further, filter segments formed from one or more gathered sheets of fibrous paper-like material according to the present disclosure may advantageously exhibit a more uniform density than conventional filter segments.

In a preferred embodiment, a filter segment according to the present invention is formed from one or more gathered textured sheets of fibrous paper-like material defined by a wrapper. The use of a textured sheet of fibrous paper-like material may advantageously facilitate the gathering of the sheet of fibrous paper-like material to form a filter segment according to the invention.

As used herein, the term "textured sheet" means a sheet that has been curled, embossed, gravure, perforated, or otherwise deformed. The textured sheet of fibrous paper-like material for use in the present invention may comprise a plurality of spaced apart indentations, protrusions, perforations or a combination thereof. In the context of the present invention, the term "crimped sheet" is intended to be synonymous with the term "corrugated sheet" and denotes a sheet having a plurality of substantially parallel ridges or corrugations.

Preferably, the crimped sheet of fibrous paper-like material has a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the filter segment and aerosol-generating article according to the invention. This advantageously promotes the gathering of the crimped sheets of fibrous paper-like material to form the filter segments. However, it will be appreciated that the crimped sheet of fibrous paper-like material for use in the present invention may alternatively or additionally have a plurality of substantially parallel ridges or corrugations disposed at acute or obtuse angles to the cylindrical axis of the filter segment.

In certain embodiments, the sheet of fibrous paper-like material for use in the present invention may be textured substantially uniformly over substantially its entire surface. For example, a crimped sheet of fibrous paper-like material for use in the present invention may comprise a plurality of substantially parallel ridges or corrugations that are substantially evenly spaced across the width of the sheet.

As an alternative to forming segments of filter material by gathering one or more sheets of fibrous paper-like material as described above, filter segments for use in aerosol-generating articles according to the invention may be formed from shreds or strands obtained by performing a cutting or shredding operation on sheets of fibrous paper-like material. As an example, a sheet of fibrous paper-like material comprising a combination of fibers as set out above may be cut into shreds or slivers having a predetermined width. The shreds or strips may additionally be cut to a predetermined length, such as, for example, about 10 mm to 15 mm. The shreds or slivers may be defined by a wrapper, such as a wrapper of (paper) filter plug segment wrapping, to form segments of filter material in a process similar to that used to form rods of shredded filler for conventional cigarettes.

Filters for use in aerosol-generating articles according to the invention may typically have a filtration efficiency of from about 45% to about 60%. Preferably, a filter for use in an aerosol-generating article according to the invention has a filtration efficiency of from about 50% to about 55%. The filtration efficiency was in accordance with IS 04387: 2000-04-01 (third edition) -cigarette-was measured using a routine analytical smoking machine to determine the total dry particulate matter free of nicotine. Filters for use in aerosol-generating articles according to the invention may comprise one or more filter elements or segments formed from the fibrous paper-like material described above.

In addition, or as an alternative, a filter element for use in an aerosol-generating article according to the invention may comprise one or more segments formed from alternative filter materials.

In some embodiments, the aerosol-generating substrate may be in the form of a rod of randomly oriented shreds, rods or sticks of tobacco material defined by a paper wrapper, as in a conventional cigarette. The filter segments or elements may be attached to the rod by means of a tipping paper.

In other embodiments, the aerosol-generating substrate may be in the form of a gathered sheet of homogenised tobacco material. Rods of this type have been described in international patent application WO-A-2012/164009 and are particularly suitable for heated aerosol-generating articles. Another alternative is known from international patent application WO-A-2011/101164 which discloses rods for heated aerosol-generating articles formed from strands of homogenized tobacco material, which rods may be formed by casting, rolling, calendering or extruding A mixture comprising particulate tobacco and at least one aerosol former to form A sheet of homogenized tobacco material.

The aerosol-generating article according to the invention preferably comprises one or more elements in addition to the rod and filter of the aerosol-generating substrate, wherein the rod, filter and one or more elements are assembled within a substrate wrapper. For example, aerosol-generating articles according to the present invention may further comprise at least one of: a mouthpiece, an aerosol-cooling element and a support element, such as a hollow cellulose acetate tube. For example, in one preferred embodiment, an aerosol-generating article comprises a rod of aerosol-generating substrate as described above, a support element located immediately downstream of the aerosol-generating substrate, an aerosol-cooling element located downstream of the support element, and an outer wrapper defining the rod, the support element and the aerosol-cooling element, arranged in linear order.

Drawings

The invention will now be further described with reference to the following examples and the accompanying drawings, in which:

figure 1 is a schematic cross-sectional side view of an aerosol-generating article according to the present invention; and

figure 2 is a graph showing the results of biodegradation tests performed on samples of fibrous paper-like material for use in aerosol-generating articles according to the invention, as illustrated in the following examples.

Detailed Description

An embodiment of an aerosol-generating article 10 according to the present invention is illustrated in figure 1. The aerosol-generating article 10 comprises a rod 12 of an aerosol-generating substrate and a mouthpiece filter 14 in axial alignment with the aerosol-generating substrate. The filter 14 is arranged downstream of the aerosol-generating substrate 12.

The filter 14 comprises a length of filter material formed from one or more sheets of fibrous paper-like material in accordance with the present invention prepared as will be described in more detail below. In more detail, one or more sheets of fibrous paper-like material are gathered and extend along substantially the entire length of the segment and across substantially the entire transverse cross-sectional area of the segment in the length of filter material.

In addition, the aerosol-generating article 10 comprises a hollow cellulose acetate tube 16 and a spacer element 18 arranged between the rod 12 and the filter 14 such that all four elements are arranged sequentially and coaxially aligned. All four elements are defined by the same wrapper 20 to form the aerosol-generating article.

The rod 12 of aerosol-generating substrate is about 12 mm in length and about 7mm in diameter. The rod 12 is cylindrical and has a substantially circular cross-section. The filter 14 is substantially cylindrical in shape and has a substantially circular cross-section, having a length of about 7mm and a diameter of about 7 mm.

Example 1

Several embodiments of the fibrous paper-like material of the present invention were made at laboratory scale and tested by industry standard techniques. The hydrophobic fiber is DANUFIL manufactured by Kelheim Fibers GmbHViscose fibers. These fibers had a titer of 1.7dtex (1.53den) to 3.3dtex (2.97den) and a length of 5 mm. Various types of hydrophilic fibers are used, such as bleached or unbleached softwood fibers or bleached cellulose fibers having an SR degree of 15 degrees overall. To make a fibrous paper-like material, both types of fibers are mixed with water to obtain a slurry. The aqueous slurry thus formed was then deposited onto the foraminous forming surface of a diagonal papermaking machine to form a wet paper. The wet paper is then dried at a temperature between 80 degrees celsius and 100 degrees celsius.

The composition and properties of the five samples are shown below.

In addition, sample 5 contained 0.15% by dry weight of alkyl ketene dimer, the sizing agent.

The capillary rise of the paper sheet is measured according to ISO 8787: 1986.

The water drop value corresponds to the time necessary for one drop of water to be absorbed by the fibrous paper-like material as measured by TAPPI T432 in 1964.

For comparison, a fibrous paper-like material containing 100% by weight of unrefined softwood fibers was similarly made and tested. This control paper exhibited a capillary rise of 96 mm/10 min and a water drop of less than 2 seconds.

Example 2

Filter elements made of fibrous paper-like material were subjected to an aqueous biodegradation test. The standard methodology described in ISO 14851-determination of the final aerobic biodegradability of plastic materials in aqueous media is followed. The test measures the biodegradation of the test article caused by conditioned sludge under laboratory conditions. In more detail, the test material is brought into a liquid medium which is essentially free of other organic carbon sources and is doped with a chemically defined composition of the microorganism. During aerobic biodegradation of organic materials in aqueous media, oxygen is consumed and carbon is convertedIs carbon dioxide. By absorbing CO at regular intervals₂By titration of KOH solution to determine CO produced₂The amount of (c). Based on CO₂Yield biodegradation was calculated as the amount of test compound that had been reduced to the form of CO₂Of gaseous mineral C.

Two test articles and one reference standard were tested. The cellulose reference standard is microcrystalline cellulose powder suitable for thin layer chromatography (Avicel, FMC). Test article 1 was a smoking cigarette butt comprising tipping paper and a 26gsm fibrous paper-like filter material of the present invention made from 50% by dry weight bleached softwood fibers and 50% by dry weight Danufil Olea viscose fibers at a length of 1.7dtex (1.53den) and 5 mm. This material was found to have a contact angle in article 1 of greater than 95 degrees. The test article 2 was a smoking cigarette butt comprising the same type of tipping paper and conventional non-woven cellulose acetate as the filter material. The contact angle of the cellulose acetate in the article 2 was 90 degrees. Both article 1 and article 2 have similar lengths (27mm) and similar diameters (7.7 mm). Both articles were cut into small pieces less than 2 mm in size at the start of the test.

The test is performed three times. At the start of the test, each of the 12 reactors was filled with the same amount of mineral medium and inoculum to obtain a concentration of approximately 30 milligrams suspended solids per liter of test medium. The reference item and the test item are added directly to the reactor. A set of 3 blanks was also included. The source of the microorganisms (inoculum) is a mixture of activated sludge obtained from different wastewater treatment plants. The reactor was stirred and incubated at constant temperature (21 degrees c ± 1 degree c) in the dark for a period of 56 days.

After 14, 28, 42 and 56 days, the CO captured in the KOH solution during the test was measured₂To determine the extent of biodegradation. See fig. 2.

Table 1 shows the results after 56 days. ThCO of reference and test articles at the end of the test₂(% organic carbon content based on sample and theoretical CO input₂Yield), net CO₂Yield and percent biodegradation.

The biodegradation pattern of the article 2 comprising the fibrous paper-like material is similar to that of a reference standard cellulose. After 14 days, a biodegradation of 59.5% was reached. From then on the biodegradation rate has slowed down. Absolute biodegradation of 78.0% ± 3.1% was measured after 28 days. At the end of the test (56 days), the steady state of biodegradation reached a level of 82.7% ± 3.0%. On a relative basis, 94.2% biodegradation was calculated compared to a reference standard.

In contrast, biodegradation of the cellulose acetate-containing article 1 started almost immediately at a moderate rate, but tended to level off from day 14 onwards. After 56 days, an absolute biodegradation of 29.8% ± 1.5% was measured, or 33.9% on a relative basis compared to a pure cellulose reference standard.

From these results, it can be concluded that the test article 1 comprising the fibrous paper-like material of the invention achieved a 90% biodegradability requirement within a 56 day test.