JP2023505462A - Aerosol-generating element with filter having high content of polyhydroxyalkanoate polymer or copolymer - Google Patents

Abstract

An aerosol-generating article (10, 100, 310) is provided for generating an inhalable aerosol upon heating, the aerosol-generating article comprising a rod (12, 114, 312) of an aerosol-generating substrate and a fibrous A filter segment (18, 122, 314) formed from a filtration material, comprising a rod (12, 114, 312) and filter segments disposed in longitudinal alignment, the filter segment (18, 122) , 314) comprises at least about 85 weight percent polyhydroxyalkanoate (PHA) polymer or copolymer based on the total weight of the fibrous filtration material. [Selection drawing] Fig. 3

Description

The present invention relates to filters for aerosol-generating articles and aerosol-generating articles comprising filters. The invention further relates to an aerosol-generating system comprising an aerosol-generating device and one such aerosol-generating article.

Conventional aerosol-generating articles, such as filter cigarettes, typically consist of a cylindrical rod of tobacco cut filler surrounded by a paper wrapper and a rolled tobacco rod (often abutting end-to-end). and axially aligned cylindrical filters. Cylindrical filters typically comprise one or more plugs of fibrous filtration material (such as cellulose acetate tow) surrounded by paper plug wrap. Conventionally, the rolled tobacco rod and filter are joined by a strip of tipping wrapper, usually formed from an opaque paper material, which surrounds the entire length of the filter and adjacent portions of the rolled tobacco rod.

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are also well known in the art. Typically, in such articles the aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-generating substrate or material.

By way of example, aerosol-generating articles have been proposed in which aerosols are generated by electrical heating of an aerosol-generating substrate. Numerous prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which the aerosol is generated by the transfer of heat from one or more electrical heater elements of the aerosol-generating device to the aerosol-generating substrate of the heated aerosol-generating article. As another example, aerosol-generating articles are also known in which aerosol is generated by the transfer of heat from a combustible fuel element or heat source to an aerosol-generating substrate. The combustible fuel element or heat source may be in contact with the aerosol-generating substrate, within the aerosol-generating substrate, around the aerosol-generating substrate, or downstream of the aerosol-generating substrate.

During use of one such aerosol-generating article, the volatile compounds are released from the aerosol-generating substrate by heat transfer, and the volatile compounds are entrained in the air drawn through the aerosol-generating article. As the released compound cools, it condenses to form an aerosol.

Typically, aerosol-generating articles of the type described may include a mouthpiece with filter segments formed from a porous filtration material such as cellulose acetate. In some known aerosol-generating articles, a hollow tubular segment formed from a filtering material such as cellulose acetate is provided at a location between the aerosol-generating substrate and the mouth end of the article to provide structural strength to the article. Give.

After the aerosol-generating article is consumed and disposed of, it is desirable that all components of the article, including filtering material, be destroyed as quickly as possible. However, cellulose acetate and many other commonly used filter materials are not highly biodegradable. However, alternative dispersible or biodegradable materials often fail to provide acceptable filtration efficiencies and smoking experiences for consumers. In addition, many known dispersible and degradable materials are not suitable for use in existing manufacturing processes, and existing methods and equipment require excessively large amounts of effort to make their use commercially viable. will need to be corrected.

Additionally, cellulose acetate has been found to provide relatively high levels of adsorption and entrapment of water from mainstream smoke when used in conventional smoking articles. Therefore, the mainstream smoke delivered to the consumer is significantly reduced in moisture content and may, under certain conditions, be perceived as undesirably "dry". This can adversely affect the overall smoking experience.

Therefore, it would be desirable to provide new and improved aerosol-generating articles that have enhanced biodegradation properties compared to known articles comprising conventional filtration materials such as cellulose acetate. Also, new and improved aerosol-generating articles that provide consumers with an acceptable smoking experience, especially novel ones with the ability to reduce the effects of "dry" smoke often found in articles containing cellulose acetate as a filtration material. It would also be desirable to provide improved aerosol-generating articles.

It would be desirable to provide one such aerosol-generating article in which the withdrawal resistance (RTD) of the filtration material segments can be adjusted to achieve an acceptable RTD for the entire article. Additionally, it would be desirable to provide such aerosol-generating articles that can be effectively manufactured in automated, high-speed manufacturing processes without requiring extensive modification of existing equipment.

The present disclosure relates to aerosol-generating articles for producing an inhalable aerosol upon heating. The aerosol-generating article may comprise a rod of aerosol-generating substrate and a filter segment formed from a fibrous filtration material. The filter segment may be disposed in longitudinal alignment with the rod. The filter segment may comprise at least about 85 weight percent polyhydroxyalkanoate (PHA) polymer or copolymer, based on the total weight of the fibrous filtration material.

Additionally, the present disclosure relates to filters for aerosol-generating articles. The filter may comprise filter segments of filtration material formed from fibrous filtration material. The filter segment may comprise at least about 85 weight percent fibers comprising a polyhydroxyalkanoate PHA polymer or copolymer, based on the total weight of the fibrous filtration material.

Additionally, the present disclosure relates to a system comprising an aerosol-generating device and an aerosol-generating article for use with the aerosol-generating device. The aerosol-generating article may comprise a rod of aerosol-generating substrate and a filter segment formed from a fibrous filtration material. The filter segment may be disposed in longitudinal alignment with the rod. The filter segment may comprise at least about 85 weight percent polyhydroxyalkanoate (PHA) polymer or copolymer, based on the total weight of the fibrous filtration material.

According to the present invention, there is provided an aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising a rod of aerosol-generating substrate and a filter segment formed from a fibrous filtering material. A rod and filter segments disposed in longitudinal alignment, the filter segments comprising at least about 85 weight percent of a PHA polymer or copolymer, based on the total weight of the fibrous filter material.

According to the present invention, there is also provided a filter for an aerosol-generating article, the filter comprising a filter segment formed from a fibrous filtration material, the filter segment comprising, based on the total weight of the fibrous filtration material, at least about 85 weight percent PHA polymer or copolymer.

As used herein, the term "longitudinal" refers to the direction corresponding to the major longitudinal axis of the aerosol-generating article, extending between the upstream and downstream ends of the aerosol-generating article. As used herein, the terms "upstream" and "downstream" describe the relative positions of elements (or portions of elements) of an aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use. do.

The term "aerosol-generating article" is used herein with respect to the present invention to describe an article in which an aerosol-generating substrate is heated to generate an aerosol for delivery to a consumer. As used herein, the term "aerosol-generating substrate" means a substrate capable of releasing a volatile compound upon heating to generate an aerosol.

A conventional cigarette 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 ignites the ends of the cigarette and the resulting combustion produces inhalable smoke. In contrast, in heated aerosol-generating articles, the aerosol is generated by heating a flavor-generating substrate, such as, for example, a tobacco-derived substrate or a substrate containing an aerosol former and a flavorant. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which aerosol is generated by the transfer of heat from a combustible fuel element or heat source to a physically separate aerosol-forming material. and

As briefly mentioned above, in contrast to existing aerosol-generating articles, articles according to the present invention are formed from fibrous filtration material and have an average weight of at least about 85%, based on the total weight of the fibrous filtration material. A filter segment is provided that includes a weight percent PHA polymer or copolymer.

Therefore, in the filter segment of an aerosol-generating article according to the invention, the PHA polymer or copolymer comprises at least 85 weight percent of the fibrous filter material. This means that the remaining portion of the fibrous filtration material may contain materials other than PHA polymers or copolymers. In addition, this includes, for example, plug wrappers around fibrous filtration materials, or inserts such as flow restrictors or additive delivery materials (e.g., frangible capsules) that may be provided at locations within the filter segments. It is meant that other components of the filter segment may comprise materials other than PHA polymers or copolymers.

Fibers containing PHA polymers or copolymers (hereinafter also referred to as PHA fibers) exhibit lower hydrophilicity in aerosol-generating articles according to the present invention compared to fibers of other filtration materials such as cellulose acetate of comparable weight. It has been found that the filter segment has a significantly lower tendency to absorb water/vapor because it has a As a result, water levels in mainstream smoke can be advantageously maintained at higher levels. This directly addresses the "dry smoke" problem often encountered with conventional smoking articles and provides an improved smoking experience for the consumer.

Since PHA fibers have a much higher level of biodegradability compared to fibers of other filtration materials such as cellulose acetate, articles according to the invention have a higher overall biodegradability. At the same time, since PHA fibers are obtained by natural fermentation processes, the aerosol-generating articles according to the invention also provide improved sustainability for the manufacturing process.

By adjusting parameters such as denier per filament, total denier, cross-sectional shape, etc., it is possible to adjust the RTD of the filter segments to the desired range for any given filter length or filter design.

The term "denier per filament" (DPF) corresponds to the weight in grams of a single fiber or filament having a length of 9000 meters. Therefore, the DPF value in the present invention indicates the thickness of each individual PHA fiber within the filter segment. Denier per filament is expressed in units of denier, where 1 denier equals 1 gram per 9000 meters.

Preferably, the total denier of the filtration material comprising PHA fibers is from about 20,000 to about 50,000 or 40,000, more preferably from about 25,000 to about 30,000.

The "total denier" of a filtration material defines the total weight (in grams) of 9000 meters of combined fibers forming the filtration material. Thus, the total denier of a filter segment corresponds to the denier per filament multiplied by the total number of fibers in the filter segment.

Additionally, the overall weight of the filter may be advantageously controlled, which may also contribute to aiding biodegradation of the filter segments and the entire aerosol-generating article.

PHA properties also lead to good filter hardness, which can be further enhanced by surrounding the filter segment with a stiff plugwrap.

An aerosol-generating article according to the present invention comprises a rod of aerosol-generating substrate.

Rods of aerosol-generating substrate may be produced using randomly oriented pieces, strands, or strips of tobacco material. Alternatively, the rod of aerosol-generating substrate may be formed from an assembly of one or more sheets of tobacco material, for example as proposed in WO-A-2012/164009. Alternative rods for aerosol-generating articles formed from strands of homogenized tobacco material have also been proposed, which include particulate tobacco and at least one It may be formed by casting, rolling, calendering, or extruding a mixture containing the aerosol former. Further, the rod of aerosol-generating substrate is a homogenized tobacco material obtained by extruding a mixture comprising particulate tobacco and at least one aerosol former to form a continuous length of homogenized tobacco material. It may be formed from strands of tobacco material.

The rods of the aerosol-generating substrate preferably have an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

The aerosol-generating substrate rod preferably has an outer diameter of at least 5 millimeters. The rod of aerosol-generating substrate may have an outer diameter of about 5 millimeters to about 12 millimeters, such as an outer diameter of about 5 millimeters to about 10 millimeters, or an outer diameter of about 6 millimeters to about 8 millimeters. In one preferred embodiment, the rods of aerosol-generating substrate have an outer diameter of 7.2 millimeters to within 10 percent.

A rod of aerosol-generating substrate may have a length of about 5 millimeters to about 100 mm. The rods of aerosol-generating substrate preferably have a length of at least about 5 millimeters, and more preferably have a length of at least about 7 millimeters. Additionally or alternatively, the rods of aerosol-generating substrate preferably have a length of less than about 80 millimeters, more preferably less than about 65 millimeters, and less than about 50 millimeters. is even more preferred. In particularly preferred embodiments, the rods of aerosol-generating substrate have a length of less than about 35 millimeters, more preferably less than 25 millimeters, and even more preferably less than about 20 millimeters. preferable. In one embodiment, the rod of aerosol-generating substrate may have a length of about 10 millimeters. In one preferred embodiment, the rod of aerosol-generating substrate has a length of about 12 millimeters.

The rod of aerosol-generating substrate preferably has a substantially uniform cross-section along the length of the rod. It is particularly preferred that the rods of the aerosol-generating substrate have a substantially circular cross-section.

In preferred embodiments, the aerosol-generating substrate comprises a collection of one or more homogenized sheets of tobacco material. The one or more sheets of homogenized tobacco material are preferably textured. As used herein, the term "textured sheet" means a sheet that has been crimped, embossed, debossed, perforated, or otherwise deformed. Textured sheets of homogenized tobacco material for use in the present invention may comprise a plurality of spaced apart indentations, protrusions, perforations, or a combination thereof. According to one particularly preferred embodiment of the invention, the rod of aerosol-generating substrate comprises an assembly of crimped sheets of homogenized tobacco material surrounded by a wrapper.

As used herein, the term "crimped sheet" is intended to be synonymous with the term "crinkled sheet" and has a plurality of substantially parallel ridges or corrugations. means sheet. The crimped sheet of homogenized tobacco material preferably has a plurality of ridges or corrugations substantially parallel to the cylindrical axis of the rod according to the invention. This advantageously facilitates assembly of crimped sheets of homogenized tobacco material to form rods. However, it should be appreciated that the crimped sheet of homogenized tobacco material used in the present invention may alternatively or additionally comprise a plurality of barbs arranged at an acute or obtuse angle to the cylindrical axis of the rod. ridges or corrugations that are parallel to each other. In certain embodiments, the sheet of homogenized tobacco material used in the rods of the articles of the present invention may be textured substantially evenly over substantially its entire surface. For example, a crimped sheet of homogenized tobacco material for use in making rods for use in aerosol-generating articles according to the present invention may have a plurality of substantially parallel ridges or corrugations spaced substantially evenly across the width of the sheet. may be provided.

The sheets or webs of homogenized tobacco material used in the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis and have a tobacco content of at least about 60 weight percent on a dry weight basis. More preferably, it has a tobacco content of at least about 70 weight percent on a dry weight basis, and most preferably has a tobacco content of at least about 90 weight percent on a dry weight basis.

A sheet or web of homogenized tobacco material used for an aerosol-generating substrate may contain one or more inherent binders (i.e., tobacco intrinsic binders), one Exogenous binders (ie, tobacco exogenous binders), or combinations thereof. Alternatively or additionally, the sheet of homogenized tobacco material for use in the aerosol-generating substrate may include tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and Other additives may be included including, but not limited to, non-aqueous solvents, and combinations thereof.

Suitable exogenous binders for inclusion in sheets or webs of homogenized tobacco material for use in aerosol-generating substrates are well known in the art and include gums such as guar gum, xanthan gum, gum arabic, locust bean gum, and the like. ), cellulosic binders (e.g., hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, etc.), polysaccharides (e.g., starch, organic acids such as alginic acid, conjugate base salts of organic acids such as sodium alginate, agar, pectin, etc.), and combinations thereof.

Suitable non-tobacco fibers for inclusion in sheets or webs of homogenized tobacco material for use in aerosol-generating substrates are well known in the art and include cellulose fibers, softwood fibers, hardwood fibers, jute fibers, and combinations thereof. include, but are not limited to. Prior to inclusion in sheets of homogenized tobacco material for use in aerosol-generating substrates, the non-tobacco fibers may be treated by any suitable process known in the art, including mechanical pulping, refining, chemical pulping. , bleaching, sulfate pulping, and combinations thereof.

Substrates for heated aerosol-generating articles are typically "aerosol formers," i.e., that facilitate the formation of aerosols during use, and are preferably substantially resistant to thermal decomposition at the temperatures of use of the aerosol-generating article. Contains a compound or mixture of compounds. Examples of suitable aerosol formers include polyhydric alcohols (propylene glycol, triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (glycerol monoacetate, diacetate, or triacetate, etc.), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids such as dimethyl dodecanedioate, dimethyl tetradecanedioate, and the like. Preferred aerosol formers are polyhydric alcohols or mixtures thereof such as propylene glycol, triethylene glycol, 1,3-butanediol, most preferably glycerin.

The aerosol-generating substrate preferably comprises at least 10 weight percent aerosol former, more preferably at least 12 weight percent aerosol former, and more preferably at least about 15 weight percent aerosol former. Alternatively or additionally, the aerosol-generating substrate preferably comprises no more than 30 weight percent aerosol-forming substances, more preferably no more than about 25 weight percent aerosol-forming substances, more preferably no more than about 20 weight percent aerosol-forming substances. Including body. For example, the aerosol-generating substrate comprises from about 10 weight percent to about 30 weight percent aerosol formers, or from about 12 weight percent to about 25 weight percent aerosol formers, or from about 15 weight percent to about 20 weight percent aerosol formers. may include In one particularly preferred embodiment, the aerosol-generating substrate comprises approximately 18 weight percent aerosol formers.

In aerosol-generating articles according to the present invention, the filter segment is formed from a fibrous filtration material and comprises at least 85 weight percent PHA polymer or copolymer based on the total weight of the fibrous filtration material.

PHAs are a family of polyhydroxyesters of 3-, 4-, 5-, and 6-hydroxyalkanoic acids, produced by various bacterial species under nutrient-limiting conditions in the presence of excess carbon, and by bacterial cells. It has been found as individual cytoplasmic inclusion bodies in the Due to their excellent biocompatibility, PHAs have been proposed for use in a wide range of biomedical applications, such as drug delivery systems and tissue engineering scaffolds.

PHA molecules typically consist of 600-35,000 (R)-hydroxy fatty acid monomer units. Depending on the total number of carbon atoms in the PHA monomer, PHA can be classified as short chain length PHA (scl-PHA; 3-5 carbon atoms), medium chain length PHA (mcl-PHA; 6-14 carbon atoms ), or long chain length PHA (lcl-PHA; 15 or more carbon atoms).

The first and most widespread PHA is poly(β-hydroxybutyric acid) (PHB). The next member of the PHA family with pendant ethyl groups is poly(3-hydroxyvaleric acid) or PHV. Having an ethyl group (HV units) instead of the methyl group of PHB gives PHV more flexibility and less crystallinity than PHB.

The PHA-containing fibers provided in the filter segment of aerosol-generating articles according to the invention may be formed of any suitable PHA compound, including PHA polymers or copolymers. Suitable PHA compounds include, but are not limited to, polyhydroxypropionate, polyhydroxyvalerate, polyhydroxybutyrate, polyhydroxyhexanoate, polyhydroxyoctanoate. In one particularly preferred embodiment, the PHA compound is poly(3-hydroxybutyric acid).

In aerosol-generating articles according to the invention, the filter segment preferably comprises at least 85 weight percent PHA polymer or copolymer. While not wishing to be bound by theory, it is understood that higher PHA content within the filter segment is generally associated with improved biodegradability of the filter segment and the overall aerosol-generating article. .

In preferred embodiments, the filter segment comprises at least about 90 weight percent PHA polymer or copolymer. While not wishing to be bound by theory, it is understood that higher PHA content within the filter segment is generally associated with improved biodegradability of the filter segment and the overall aerosol-generating article. .

The filter segment is at least about 91 weight percent PHA polymer or copolymer, or at least about 92 weight percent PHA polymer or copolymer, or at least about 93 weight percent PHA polymer or copolymer, or at least about 94 weight percent PHA polymer or copolymer It is more preferable to include In some particularly preferred embodiments, the filter segment comprises at least about 95 weight percent PHA polymer or copolymer.

The remaining fibers within the PHA filter segment may comprise any suitable material. Suitable fibrous materials will be well known to those skilled in the art. Suitable fibrous materials also include, but are not limited to, polylactic acid (PLA), cellulose acetate.

In some embodiments, the filter segment may contain a portion of cellulose acetate. While not wishing to be bound by theory, it is believed that a certain amount of cellulose acetate in the filter segment not only may facilitate manufacture of the filter segment, but also provide desirable filtration and mechanical properties for the filter segment. It is understood that the

In certain embodiments, the filter segment comprises at least about 5 weight percent cellulose acetate. As an example, the filter segment may comprise at least about 6 weight percent cellulose acetate, or at least about 7 weight percent cellulose acetate, or at least about 8 weight percent cellulose acetate, or at least about 9 weight percent cellulose acetate. In some embodiments, the filter segment comprises at least about 10 weight percent cellulose acetate.

In aerosol-generating articles according to the invention, the filter segment preferably comprises less than about 15 weight percent cellulose acetate.

In some embodiments, the filter segment comprises less than about 5 weight percent cellulose acetate, preferably less than 3 weight percent cellulose acetate, more preferably less than 1 weight percent cellulose acetate, even more preferably 0.1 weight percent Contains less than cellulose acetate. This may advantageously further contribute to improved biodegradability of the filter segment and the overall aerosol-generating article.

Aerosol-generating articles according to the present invention preferably contain no more than about 10 weight percent cellulose acetate measured with respect to the total weight of the aerosol-generating article. More preferably, aerosol-generating articles according to the present invention comprise no more than about 7 weight percent cellulose acetate measured with respect to the overall weight of the aerosol-generating article. Even more preferably, aerosol-generating articles according to the present invention comprise no more than about 5 weight percent cellulose acetate measured with respect to the overall weight of the aerosol-generating article. This is advantageous not only because the filter segments have low or no cellulose acetate content, but also because any other component of the article containing the fibrous filtration material contains little or no cellulose acetate. indicate not to Embodiments of aerosol-generating articles according to the present invention having such low cellulose acetate content exhibit particularly advantageous biodegradability properties.

In some preferred embodiments, aerosol-generating articles according to the present invention comprise no more than about 3 weight percent cellulose acetate measured with respect to the overall weight of the aerosol-generating article. More preferably, aerosol-generating articles according to the present invention contain no more than about 2 weight percent cellulose acetate measured with respect to the overall weight of the aerosol-generating article. Even more preferably, aerosol-generating articles according to the present invention comprise no more than about 1 weight percent cellulose acetate measured with respect to the overall weight of the aerosol-generating article.

In some highly preferred embodiments, aerosol-generating articles according to the present invention are substantially free of cellulose acetate.

In some embodiments, the filter segment further comprises at least about 5 weight percent of at least one biodegradable polymer, wherein the biodegradable polymer is starch, polybutylene succinate (PBS), polybutyrate adipate terephthalate (PBAT ), thermoplastic starch and thermoplastic starch blends (TPS), polycaprolactone (PCL), polyglycolide (PGA), polyvinyl alcohol (PVOH/PVA), viscose, regenerated cellulose, polysaccharides, degree of substitution (DS) of 2 less than .1 selected from the group consisting of cellulose acetate, polyamides, protein-based biopolymers, chitosan-chitin-based biopolymers, and combinations thereof. The inventors have found that the inclusion of one or more of these components in the blend forming the fibrous material of the filter segment further contributes to enhanced biodegradability of the filter segment and of the overall aerosol-generating article. found to do.

Additionally, while it has previously been found to be technically difficult to produce PHA-containing filaments or fibers using existing techniques and equipment, the inventors have surprisingly found that PHA We have found that it is possible to produce filaments or fibers that incorporate high levels of PHA as this makes it easier to form filaments by spinning techniques when combined in a blend of the following.

In preferred embodiments, the filter segment comprises at least about 10 weight percent of one such additional biodegradable polymer. More preferably, the filter segment comprises at least about 11 weight percent, or at least 12 weight percent, or at least 13 weight percent, or at least 14 weight percent of the additional biodegradable polymer. Even more preferably, the filter segment comprises at least about 15 weight percent of one such additional biodegradable polymer.

In particularly preferred embodiments, the at least one biodegradable polymer is one or more of PBAT, PCL, PBS. Without wishing to be bound by theory, the inventors believe that the use of one or more of these selected biodegradable polymers improves the mechanical properties, thermal properties, and morphology of the polymer mixture. It was found that it contributes to the improvement of scientific characteristics. In particular, the combined use of PBAT and PBS has been found to provide a particularly well-balanced mechanical properties, particularly in terms of tensile strength and elongation.

In some embodiments, the fibrous filtration material comprises at least about 3 weight percent plasticizer selected from triacetin, triethylene glycol diacetate (TEGDA), ethylene vinyl acetate, polyvinyl alcohol, starch, or combinations thereof. include.

In some embodiments, the fibrous filtration material also further comprises a water-based adhesive. This has the effect of structurally reinforcing the structure of the hollow tube segment. By way of example, compounds such as starch glue, methylcellulose, or polyvinyl acetate may be used for this purpose.

The fibrous filtration material from which the filter segments are formed preferably comprises a plurality of fibers comprising a PHA polymer or copolymer and having a denier per filament of at least about 1. More preferably, the fibrous filtration material from which the filter segments are formed comprises a plurality of fibers comprising a PHA polymer or copolymer and having a denier per filament of at least about 2. Even more preferably, the fibrous filtration material from which the filter segments are formed comprises a plurality of fibers comprising a PHA polymer or copolymer and having a denier per filament of at least about 3.2.

In a preferred embodiment, the fibrous filtration material from which the filter segments are formed comprises a plurality of fibers comprising a PHA polymer or copolymer and having a denier per filament of about 10 or less. More preferably, the fibrous filtration material from which the filter segments are formed comprises a plurality of fibers comprising a PHA polymer or copolymer and having a denier per filament of about 7.5 or less. Even more preferably, the fibrous filtration material from which the filter segments are formed comprises a plurality of fibers comprising a PHA polymer or copolymer and having a denier per filament of about 5 or less.

In some embodiments, the fibrous filtration material from which the filter segments are formed comprises a PHA polymer or copolymer and from about 1 to about 10, more preferably from about 2 to about 10, even more preferably about 3. comprising a plurality of fibers having a denier per filament of from 2 to about 10; In other embodiments, the fibrous filtration material from which the filter segments are formed comprises a PHA polymer or copolymer and a It preferably comprises a plurality of fibers having a denier per filament of from about 3.2 to about 7.5. In a further embodiment, the fibrous filtration material from which the filter segments are formed comprises a PHA polymer or copolymer and has about 1 to about 5, more preferably about 2 to about 5, even more preferably about 3. It comprises a plurality of fibers having a denier per filament of 2 to about 5.

Without wishing to be bound by theory, the inventors have found that a relatively low RTD is obtained when the filter segment is formed of PHA fibers with a relatively low DPF of 1.5-3.2. , which may be desirable for certain filter designs. One such low range DPF also advantageously reduces the overall weight of the filter segment, which further improves the biodegradability of the aerosol-generating article.

The cross-sectional shape of the PHA fibers may be varied, for example, to control the external surface area of the fibers within the filter. By controlling the external surface area of the PHA fibers, the total surface area of the PHA fibers exposed to mainstream smoke as it passes through the filter segment may also be controlled. This results in some control over the filtration properties of the PHA fibers, such as the amount of water adsorbed by the fibers.

Preferably, the total external surface area of the PHA fibers in the filter segment is from about 0.15 square meters/gram to about 0.55 square meters/gram (additional subranges).

The PHA fibers may have a substantially round cross-section. In such embodiments, the total external surface area of the PHA fibers within the filter segment is preferably from about 0.15 square meters/gram to about 0.30 square meters/gram.

The PHA fibers may have a Y-shaped cross-section. In such embodiments, the total external surface area of the PHA fibers within the filter segments is preferably from about 0.25 square meters/gram to about 0.55 square meters/gram.

The PHA filter segment of an aerosol-generating article according to the invention may be adapted to provide a desired level of resistance to withdrawal (RTD). Advantageously, the PHA fibers can be arranged to provide a relatively high RTD to the PHA filter segment. Accordingly, PHA filter segments are particularly suitable for use in filters of combustible smoking articles where relatively high RTDs are typically desired. Alternatively, PHA filter segments may be particularly suitable in aerosol-generating articles where relatively short mouthpieces or filters are preferred because they can still provide acceptable RTDs.

In aerosol-generating articles according to the present invention, the RTD of the PHA filter segments for 27 millimeter filter segments is preferably at least about 25 millimeters _H2O . More preferably, the RTD of the PHA filter segment for a 27 millimeter filter segment is at least about 50 millimeters _H2O , and more preferably at least about 100 millimeters _H2O . Even more preferably, in aerosol-generating articles according to the present invention, the RTD of the PHA filter segment for a 27 millimeter filter segment is at least about 150 millimeters _H2O , more preferably at least about 180 millimeters _H2O . preferable. The RTD of the PHA filter segments for 27 millimeter filter segments is preferably no greater than about 300 millimeters _H2O , more preferably no greater than about 250 millimeters _H2O . For example, the RTD of the PHA filter segment for a 27 millimeter filter segment is from about 25 millimeters _H2O to about 300 millimeters _H2O , or from about 50 millimeters _H2O to about 300 millimeters _H2O , or from about 100 millimeters H2O. from about 150 millimeters _H2O to about 250 millimeters _H2O , or from about 180 millimeters _H2O to about 250 _{millimeters H2O ,} or from about 200 millimeters _H2O. may

In aerosol-generating articles according to the present invention, the RTD of the PHA filter segment (based on the length of the PHA filter segment within the article) is preferably at least about 25 millimeters _H2O . More preferably, the RTD of the PHA filter segment is at least about 50 millimeters _H2O , more preferably at least about 100 millimeters _H2O . Even more preferably, in aerosol-generating articles according to the present invention, the RTD of the PHA filter segment is at least about 150 millimeters _H2O , more preferably at least about 180 millimeters _H2O . The RTD of the PHA filter segment (based on the length of the PHA filter segment within the article) is preferably no greater than about 300 millimeters _H2O , more preferably no greater than 250 millimeters _H2O . For example, the RTD of the PHA filter segment is from about 25 millimeters _H2O to about 300 millimeters _H2O , or from about 50 millimeters _H2O to about 300 millimeters _H2O , or from about 100 millimeters _H2O to about 250 millimeters H2O. ₂ O, or from about 150 millimeters H ₂ O to about 250 millimeters H ₂ O, or from about 180 millimeters H ₂ O to about 250 millimeters H ₂ O, or approximately 200 millimeters H ₂ O.

In aerosol-generating articles according to the present invention, the RTD of the PHA filter segment (based on the length of the PHA filter segment within the article) is preferably at least about 3020 millimeters _H2O . More preferably, the RTD of the PHA filter segment is at least about 22 millimeters _H2O , more preferably at least about 25 millimeters _H2O . Even more preferably, in aerosol-generating articles according to the present invention, the RTD of the PHA filter segment is at least about 28 millimeters _H2O , more preferably at least about 30 millimeters _H2O . The RTD of the PHA filter segment (based on the length of the PHA filter segment within the article) is preferably no greater than about 45 millimeters _H2O , more preferably no greater than 40 millimeters _H2O . For example, the RTD of the PHA filter segment is from about 20 millimeters _H2O to about 45 millimeters H2O, or from about 22 millimeters _H2O to about 45 millimeters _H2O , or from about 25 millimeters _{H2O to} about 40 millimeters H2O. ₂ O, or from about 28 millimeters H ₂ O to about 40 millimeters H ₂ O, or from about 30 millimeters H ₂ O to about 40 millimeters H ₂ O, or from about 37 millimeters H ₂ O.

"Pull out resistance" refers to the static pressure difference between the two ends of the sample as it is traversed by the air stream under steady conditions with a volumetric flow rate of 17.5 milliliters/second at the output end. The RTD of a sample can be measured using the method described in ISO Standard 6565:2002.

Filter segments of aerosol-generating articles according to the present invention may have a lower RTD compared to cellulose acetate fiber filter segments, which may be desirable for certain applications. For example, a lower RTD may be advantageous if a lower filtration efficiency is desired or if a longer filter is preferred.

The filter segment of the aerosol-generating article according to the invention has additionally been found to provide good stability at RTD, meaning that high variability in RTD can be advantageously avoided. For example, in twenty samples of aerosol-generating articles according to the invention, there will typically be a standard deviation from the target RTD of 2-10 percent, more preferably 2-5 percent.

The fibers comprising the PHA polymer or copolymer of the filter segment are preferably crimped.

In some embodiments, the filter segment may include one or more additives to reduce specific constituents in mainstream smoke. As an example, the filter segment preferably contains additives for the reduction of phenol and phenol derivatives. Suitable additives will be well known to those skilled in the art. Suitable additives also include, but are not limited to, polyethylene glycol (PEG), triacetin, triethyl citrate, cellulose acetate flakes, or combinations thereof.

Preferably, the filter segment comprises from about 3 weight percent to about 15 weight percent additive, more preferably from about 5 weight percent to 9 weight percent additive.

In certain preferred embodiments of the invention, the PHA filter segment comprises polyethylene glycol such as PEG400.

The combination of PHA with additives (such as PEG) for the reduction of phenolic compounds from mainstream smoke has been found to be particularly effective. PHA fibers generally provide good filtration efficiency for undesirable smoke constituents, but are less effective at removing phenolic compounds. By incorporating compounds that specifically reduce the level of phenolic compounds in mainstream smoke, it is possible to further optimize the filtration capacity of the filter segments of aerosol-generating articles according to the invention. This results in improved sensory properties of the aerosol delivered to the consumer.

In particularly preferred embodiments, the filter segment further comprises at least about 5 weight percent polyethylene glycol, based on the total weight of the filtration material. The filter segments preferably contain no more than 10 weight percent polyethylene glycol, based on the total weight of the filtering material.

In another preferred embodiment of the invention the PHA filter segment further comprises a mixture of cellulose acetate and triacetin. Preferably, the mixture comprises at least 90 weight percent triacetin and up to 10 weight percent cellulose acetate. The mixture may be formed by adding cellulose acetate flakes to triacetin to form a solution. The solution may then be sprayed onto the PHA fibers within the PHA filter segment. This combination has been found to advantageously replicate the combined effect of triacetin and cellulose acetate fibers in conventional cigarette filters.

As noted above, due to the lower affinity of PHA fibers for water, PHA fibers have been found to absorb less water from mainstream smoke than comparable amounts of cellulose acetate fibers. As demonstrated in the examples below, the amount of water absorbed by PHA filter segments is significantly lower than the amount of water absorbed by equivalent filter segments formed from equivalent weights of cellulose acetate fibers.

For example, when exposed to liquid water, the filter segments of the aerosol-generating articles of the present invention absorb less than half the amount of water absorbed under the same conditions by comparable filter segments formed from cellulose acetate fibers. preferably not.

The reduced absorption of water by the PHA fibers of the filter segments of the present invention compared to cellulose acetate results in higher levels of water in the mainstream smoke delivered from the aerosol-generating article during use.

For example, the amount of water in mainstream smoke collected during smoking of a combustible smoking article comprising a filter according to the present invention using PHA fibers under ISO conditions is comparable to that of filter segments of cellulose acetate tow under the same conditions. is at least 10 percent higher, preferably at least 15 percent higher than the amount of water in mainstream smoke collected during smoking of a comparable combustible smoking article having.

Therefore, an aerosol-generating article with a filter that includes a PHA filter segment can deliver mainstream smoke with higher moisture levels, which is more sensorially acceptable to consumers. In particular, the "dry smoke" effect that may be experienced during smoking of aerosol-generating articles using conventional cellulose acetate filters can be advantageously reduced.

Fibers containing PHA polymers or copolymers of filter segments may be manufactured by one of several techniques including melt spinning, gel spinning, and electrospinning. Fibers comprising PHA polymers or copolymers of filter segments in aerosol-generating articles according to the present invention are preferably manufactured by melt spinning. Melt spinning is often considered the most economical spinning process compared to solution spinning, as there is no need to recover or evaporate the solvent. Furthermore, spinning speeds using melt spinning are generally quite high, which is advantageous in terms of overall productivity and manufacturing efficiency.

In this process, a viscous melt of a polymer or polymer blend is forced through a spinneret containing numerous holes into a chamber where a blast of cold air or gas is directed onto the surface of the filaments emanating from the spinneret. be directed. When air hits the filament, it solidifies and is collected, such as on a take-up wheel. The melt spinning process is advantageously characterized by a defined filament cross-sectional geometry and yields a wide variety of finenesses and filament counts. By increasing the number of spinneret openings, high spinning capacities can be achieved that are difficult to match with other spinning processes.

In some embodiments, filter segments may typically have a length of at least about 4 millimeters. Preferably, the length of the filter segment is at least about 5 millimeters. More preferably, the length of the filter segment is at least about 7 millimeters. Even more preferably, the length of the filter segment is at least about 10 millimeters.

In such embodiments, the filter segment may typically have a length of about 30 millimeters or less. Preferably, the length of the filter segment is about 27 millimeters or less. More preferably, the length of the filter segment is about 25 millimeters or less. Even more preferably, the length of the filter segment is about 20 millimeters or less.

In such embodiments, the filter segment length is preferably from about 5 millimeters to about 30 millimeters, more preferably from about 10 millimeters to about 30 millimeters, even more preferably from about 15 millimeters to about 30 millimeters, most preferably about 20 millimeters. millimeters to about 30 millimeters. Alternatively, in such embodiments, the filter segment length may be from about 4 millimeters to about 27 millimeters, preferably from about 5 millimeters to about 27 millimeters, more preferably from about 10 millimeters to about 27 millimeters, even more preferably from about 15 millimeters to about 27 millimeters, and most preferably from about 20 millimeters to about 27 millimeters. As yet another alternative, in such embodiments, the length of the filter segment may be from about 4 millimeters to about 25 millimeters, preferably from about 5 millimeters to about 25 millimeters, more preferably from about 10 millimeters to about 25 millimeters. About 25 millimeters, even more preferably from about 15 millimeters to about 30 millimeters, and most preferably from about 20 millimeters to about 25 millimeters.

The filter segment preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The filter segments preferably have an outer diameter of at least 5 millimeters. The filter segment may have an outer diameter of about 5 millimeters to about 12 millimeters, such as about 5 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters. In one preferred embodiment, the filter segments have an outer diameter within 10 percent of 7.2 millimeters.

Preferably, in aerosol-generating articles according to the invention, the filter segments have an average radial hardness of at least 80 percent, more preferably at least 85 percent. Thus, the filter segment can provide a desired level of filter hardness comparable to that provided by conventional cellulose acetate tow filters. If desired, the aerosol-generating article according to the present invention can be enhanced by surrounding the filter segment with a stiff plugwrap, such as a plugwrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm. The radial stiffness of the filter segments may be further increased.

式中、Ｄ_Sは元の（押圧されていない）直径であり、またＤ_dは設定継続時間の間、設定された負荷を加えた後の押圧された直径である。材料が硬いほど硬度は１００％に近づく。 As used herein, the term "radial stiffness" refers to the resistance to compression in a direction transverse to the longitudinal axis of the filter segment. The radial hardness of the aerosol-generating article around the filter is measured by applying a load across the article at the location of the filter in a direction transverse to the longitudinal axis of the article and the average compressed diameter of the article ( may be determined by measuring the mean value). Radial hardness is given by:

where D _S is the original (unpressed) diameter and D _d is the pressed diameter after applying a set load for a set duration. Harder materials approach 100% hardness.

To determine the hardness of a portion of an aerosol-generating article (such as a filter segment), the aerosol-generating article should be aligned in a plane and parallel, and the same portion of each aerosol-generating article to be tested is held for a set duration. , should receive the set load. This test was carried out using the well-known DD60A Densimeter instrument (manufactured and marketed by Heinr Borgwaldt GmbH, Germany) fitted with a measurement head for aerosol-generating articles such as cigarettes and Comes with a container.

Loading is applied using two load-applying cylindrical rods that extend across the diameter of all the aerosol-generating articles at once. The standard test method for this instrument should be such that 20 contact points between the aerosol-generating article and the load-applying cylindrical rod are produced. In some cases, the filters tested are sufficient so that only 10 aerosol-generating articles are required to form 20 contact points with each smoking article contacting both loading rods. (because they are long enough to extend between both rods). In other cases, if the filter is too short to accomplish this, 20 aerosol-generating articles should be used to create 20 contact points, as discussed further below. The aerosol-generating article is in contact with only one of the load application rods.

Two additional fixed cylindrical rods are positioned below the aerosol-generating article to support the aerosol-generating article and to counteract the load applied by each of the load-applying cylindrical rods.

For standard operating procedures for such devices, a total load of 2 kg is applied for 20 seconds. After 20 seconds have elapsed (and with the load still applied to the smoking article), the depression on the load-applying cylindrical rod is determined and then used to calculate the hardness from the above equation. The temperature is kept within the region of 22°C ± 2°C. The test described above is called the DD60A test. The standard method of measuring filter hardness is when the aerosol-generating article has not yet been consumed. Additional information regarding average radial hardness measurements can be found, for example, in US Published Patent Application Publication No. 2016/0128378.

In some embodiments, the filter segment described above is the only segment formed from the filtering material that forms the mouth end filter of the aerosol-generating article. In other embodiments, the aerosol-generating article may comprise one or more additional filter segments formed from a filtration material, upstream or downstream of the filter segment comprising the PHA polymer or copolymer as described above. may be provided downstream. For example, a filter segment comprising a PHA polymer or copolymer is combined with one or more axially aligned filter plugs formed from a fibrous filtration material that may or may not contain PHA-containing fibers. good too. Alternatively or additionally, a filter segment comprising a PHA polymer or copolymer may be combined with one or more tubular elements, such as tubular elements formed from fibrous filtration material or cardboard tubes. Alternatively or additionally, a PHA filter segment may be combined with an aerosol cooling element.

The filter segment of an aerosol-generating article according to the invention may optionally contain a flavorant. Flavoring agents can be incorporated using a variety of different means, which will be well known to those skilled in the art. For example, flavorants may be incorporated in the form of capsules that may be provided within the filter segment of the aerosol-generating article comprising the PHA polymer or copolymer, or within additional filter segments.

The filter segment of an aerosol-generating article according to the invention is surrounded by an outer wrapper (e.g., tipping wrapper) that surrounds the filter segment, the downstream end of the aerosol-generating substrate, and any additional components that may be provided therebetween. preferably. The tipping wrapper may comprise removable tipping wrapper portions as described in WO-A-2017/162838. This allows at least a portion of the tipping wrapper to be removed prior to disposal of the aerosol-generating article. Removal of the tipping wrapper exposes the underlying filter segments and thus may advantageously speed the biodegradation of the filter material.

In some embodiments, aerosol-generating articles according to the present invention may further comprise one or more additional elements typically assembled with the rod of aerosol-generating substrate within the same wrapper. Examples of such additional elements include support elements adapted to enhance the structural strength of the aerosol-generating article, cooling elements adapted to favor cooling of the aerosol before it reaches the filter segment, and the like. is mentioned.

For example, in one preferred embodiment, the aerosol-generating article comprises a rod of aerosol-generating substrate, a support element immediately downstream of the support element, and an aerosol downstream of the support element in a linear, continuous arrangement. A cooling element and an outer wrapper enclosing the rod, the support element and the aerosol cooling element. Rods, support elements and aerosol cooling elements are provided in a linear arrangement and upstream of the filter segments as described above. In one particularly preferred embodiment, the rods, support elements and aerosol cooling elements are provided in a linear arrangement and immediately upstream of the filter segments as described above.

For example, the support element may be provided in the form of a tubular element of fibrous filtration material. A fibrous filter material may include cellulose acetate. In preferred embodiments, the fibrous filter comprises a polyhydroxyalkanoate (PHA) polymer or copolymer.

In another preferred embodiment of the invention, the aerosol-generating article comprises, in a linear continuous arrangement, an aerosol-generating substrate, a transfer element, an aerosol-cooling element, a spacer element, and filter segments as described above. Prepare.

In certain preferred embodiments of the invention, the aerosol-generating article further comprises a combustible heat source at the upstream end of the aerosol-generating article in contact with the upstream end of the aerosol-generating substrate. For example, the aerosol-generating article may include a carbonaceous heat source at the upstream end to heat the aerosol-generating substrate to generate an aerosol during use. Suitable carbonaceous heat sources will be well known to those skilled in the art.

The invention will now be further described with reference to the figures.

FIG. 1 shows a schematic longitudinal cross-section of an aerosol-generating article according to a first embodiment of the invention for use in an aerosol-generating device with a heater element. FIG. 2 shows a schematic longitudinal cross-sectional view of an aerosol-generating article according to a second embodiment of the invention with an integrated heat source. Figure 3 shows a schematic longitudinal cross-sectional view of an aerosol-generating article according to a third embodiment of the invention. FIG. 4 shows a schematic longitudinal cross-sectional view of an aerosol-generating system comprising an electrically-operated aerosol-generating device and the aerosol-generating article shown in FIG.

The aerosol-generating article 10 shown in FIG. 1 comprises a rod of aerosol-generating substrate 12 , a support element 14 provided as a hollow tubular element, a cooling element 16 and a mouth end filter segment 18 . These four elements are arranged in continuous and coaxial alignment and surrounded by substrate wrapper 20 to form aerosol-generating article 10 . Aerosol-generating article 10 has a mouth end 22 and a distal end 24 located at the opposite end of the article to mouth end 22 . The aerosol-generating article 10 shown in FIG. 1 is particularly suitable for use in an electrically operated aerosol-generating device that includes a heater for heating the rod of aerosol-generating substrate.

In use, air is drawn through the aerosol-generating article from the distal end 24 to the mouth end 22 by the user. The distal end 24 of the aerosol-generating article may also be described as the upstream end of the aerosol-generating article 10 and the mouth end 22 of the aerosol-generating article 10 may also be described as the downstream end of the aerosol-generating article 10. There is Elements of the aerosol-generating article 10 located between the mouth end 22 and the distal end 24 can be described as being upstream of the mouth end 22, or alternatively downstream of the distal end 24. It can be described that there is

Aerosol-generating substrate 24 is located at the farthest distal or upstream end of aerosol-generating article 10 . In the embodiment illustrated in FIG. 1, the aerosol-generating substrate 12 comprises an assembly of crimped, homogenized sheets of tobacco material surrounded by a wrapper. The crimped sheet of homogenized tobacco material contains glycerin as an aerosol former.

The support element 14 is positioned immediately downstream of the aerosol-generating substrate 12 and abuts the aerosol-generating substrate 12 . In the embodiment shown in Figure 1, the support element is a hollow tube formed of fibrous filtration material. The support element 14 positions the aerosol-generating substrate 12 at the farthest distal end 24 of the aerosol-generating article 10 so that it can be penetrated by the heating element of the aerosol-generating device. In practice, the support element 14 is driven downstream within the aerosol-generating article 10 toward the aerosol-cooling element 16 as the aerosol-generating device heating element is inserted into the aerosol-generating substrate 12 . work to prevent Support element 14 also acts as a spacer to separate aerosol-cooling element 16 of aerosol-generating article 10 from aerosol-generating substrate 12 .

An aerosol cooling element 16 is positioned immediately downstream of support element 14 and abuts support element 14 . In use, volatiles emitted from the aerosol-generating substrate 12 pass along the aerosol-cooling element 16 toward the mouth end 22 of the aerosol-generating article 10 . Volatiles may cool within the aerosol cooling element 16 to form an aerosol that is inhaled by the user. In the embodiment illustrated in FIG. 1 the aerosol cooling element comprises a tubular element 20 . A collection of crimped sheets of polylactic acid define a plurality of longitudinal channels extending along the length of the aerosol cooling element 40 .

A filter segment 18 is located immediately downstream of the aerosol cooling element 16 and abuts the aerosol cooling element 16 . In the embodiment illustrated in FIG. 1, filter segment 18 is a single cylinder of fibrous filtration material formed from a plurality of PHA fibers having a denier per filament of approximately 3 and a total denier of approximately 27,000. Equipped with a plug. The PHA fibers have a round cross-sectional shape and are substantially longitudinally aligned with each other along the length of the filter segment. The exposed surface area of PHA fibers corresponds to about 0.16 square meters/gram. PHA fibers are formed and crimped by a melt spinning process. More specifically, the fiber contains about 85 weight percent PHA polymer or copolymer combined with 15 weight percent PBAT and PBS blend, with a 1:1 ratio of PBAT to PBS. The plug of fibrous filtration material is surrounded by a plug wrap (not shown).

Aerosol-generating article 100 shown in FIG. These elements are arranged in continuous and coaxial alignment and surrounded by a substrate wrapper to form the aerosol-generating article 100 .

Combustible heat source 112 comprises a substantially circular cylindrical body of carbonaceous material having a length of approximately ten millimeters. Combustible heat source 112 is a blind heat source. In other words, combustible heat source 112 does not have any air channels extending therethrough.

A rod of aerosol-generating substrate 114 is disposed at the proximal end of combustible heat source 112 . Aerosol-generating substrate 114 comprises a substantially circular cylindrical plug 124 of tobacco material surrounded by filter plug wrap 126 .

A non-combustible, substantially air-impermeable first barrier 128 is disposed between the proximal end of combustible heat source 112 and the distal end of aerosol-generating substrate 114 . The first barrier 128 comprises a disk of aluminum foil. First barrier 128 also provides a thermally conductive member between combustible heat source 112 and aerosol-generating substrate 114 to conduct heat from the proximal surface of combustible heat source 112 to the distal surface of aerosol-generating substrate 114 . Form.

Thermally conductive element 130 surrounds a proximal portion of combustible heat source 112 and a distal portion of aerosol-forming substrate 114 . Thermally conductive element 130 comprises a tube of aluminum foil. Thermally conductive element 130 is in direct contact with the proximal portion of combustible heat source 112 and filter plug wrap 126 of aerosol-generating substrate 114 .

Mouthpiece filter 122 comprises a single cylindrical plug 126 of fibrous filtration material formed from a plurality of PHA fibers having a denier per filament of approximately 3 and a total denier of approximately 27,000. The PHA fibers have a round cross-sectional shape and are substantially longitudinally aligned with each other along the length of the filter segment. The exposed surface area of PHA fibers corresponds to about 0.16 square meters/gram. PHA fibers are formed and crimped by a melt spinning process. The plug of fibrous filtration material is surrounded by a plug wrap (not shown).

The aerosol-generating article 310 shown in FIG. 3 is a combustible smoking article comprising an aerosol-generating substrate 312 and a filter 314 disposed in coaxial alignment with one another. Aerosol-generating substrate 312 comprises a tobacco rod surrounded by an outer wrapper (not shown). A tipping wrapper 316 surrounds both the filter 314 and the end portion of the aerosol-generating substrate 312 and attaches the filter 314 to the aerosol-generating substrate 312 .

Filter 314 comprises a single cylindrical plug 318 of fibrous filtration material formed from PHA fibers having a denier per filament of approximately 3 and a total denier of approximately 27,000. The PHA fibers have a round cross-sectional shape and are substantially longitudinally aligned with each other along the length of the filter segment. The exposed surface area of PHA fibers corresponds to about 0.16 square meters/gram. PHA fibers are formed and crimped by a melt spinning process. The plug of fibrous filtration material is surrounded by a plug wrap (not shown).

FIG. 4 shows a portion of an electrically operated aerosol-generating system 200 that utilizes a heater blade 210 for heating the rods of the aerosol-generating substrate 12 of the aerosol-generating article 10 shown in FIG. A heater blade 210 is mounted within an aerosol-generating article chamber within the housing of an electrically operated aerosol-generating device 212 . The aerosol-generating device 212 defines a plurality of air holes 214 for allowing air to flow to the aerosol-generating article 10, as illustrated by the arrows in FIG. Aerosol generator 212 includes a power supply and electronics, which are not shown in FIG.

Comparative Example [Incorporate discussion of Test 1 and Test 2 from IDR? ]
PHA filter segments according to the present invention were prepared from PHA fibers with the parameters shown in Table 1 below. PHA fibers were formed using a melt spinning process, after which the fibers were crimped and formed into filter segments using standard filter making equipment. For comparison purposes, conventional cellulose acetate (CA) tow filter segments were prepared with similar values of denier per filament (dpf) and total denier.

In a first test, the water absorption upon exposure to water of PHA filter segments according to the invention and CA filter segments were compared. For each filter segment, the plug wrap was removed and the filter segment was attached to the probe of a force tensiometer (KRUSS force tensiometer, model K100). The filter segment is moved down towards the water container by the probe and automatically stops when the filter segment contacts the water. The filter segment is left in contact with water for 300 seconds to allow the filter material to absorb the water, then the filter segment is weighed to determine the amount of water absorbed during the test period. This test was repeated three times for each of the PHA and CA filter segments and the average water absorption was calculated as shown in Table 2 below.

The amount of water absorbed by the PHA filter segments according to the invention during the test was therefore less than 40 percent of the amount of water absorbed by the CA filter segments. This test therefore demonstrates the significantly reduced water affinity of the PHA filter segments according to the invention compared to conventional CA filter segments.

In a second test, the water absorption upon exposure to moisture of PHA filter segments according to the present invention and CA filter segments were compared. For each filter segment, the plug wrap was removed and the fibers forming the filter segment were placed in a petri dish and exposed to air at 22 degrees Celsius and 50 percent relative humidity for 70 hours. This was done on a Vapor Sorption Analyzer (ProUmid SPSx-1μ). For each filter segment, the fiber is weighed at the beginning of the test and the change in weight over time due to absorption of water vapor by the fiber is determined. For each of the PHA filter segment and the CA filter segment, a percent sample mass difference (% dm) value, which expresses the increase in sample weight as a percentage of the original weight, was calculated. The %dm values for each of the samples at the end of the 70 hour test are shown in Table 3 below.

The results demonstrate that the amount of water vapor absorbed by the cellulose acetate fibers during the 70 hour test was over 50 times greater than the amount of water vapor absorbed by the PHA fibers. The PHA fibers absorbed very little water vapor during the test. This further demonstrates the significantly reduced water affinity of the PHA filter segments according to the present invention compared to conventional CA filter segments.

In a third test, the absorption of water from mainstream smoke by PHA filter segments according to the invention and conventional CA filter segments was compared. A conventional smoking article was prepared as described above with reference to FIG. 3 using a combustible tobacco rod and a single segment of filter material forming the filter for each of the filter segments. Each of the smoking articles is then smoked in a cigarette smoking machine under ISO conditions as set forth in ISO 3308:2000 (35 ml smoke volume, 2 second smoke duration every 60 seconds) and the resulting A smoke analysis was performed. For each of the filter segments, the amount of water in mainstream smoke collected during the smoking test was measured, as shown in Table 4.

This indicates that, when smoked under comparable conditions, smoking articles incorporating PHA filter segments produce mainstream smoke with a moisture content approximately 20 percent higher than that of mainstream smoke from smoking articles containing CA filter segments. demonstrate that This demonstrates that PHA filter segments do not absorb less water from mainstream smoke than CA filter segments, thereby reducing the potential problem of dry smoke as described above.

Claims (15)

An aerosol-generating article for producing an inhalable aerosol upon heating, comprising:
a rod of aerosol-generating substrate, said aerosol-generating substrate comprising at least 10 weight percent aerosol former;
a filter segment formed from a fibrous filtration material, the filter segment disposed in longitudinal alignment with the rod;
An aerosol-generating article, wherein said filter segment comprises at least about 85 weight percent polyhydroxyalkanoate (PHA) polymer or copolymer, based on the total weight of said fibrous filtration material. 3. The aerosol-generating article of claim 1, wherein the filter segment comprises at least about 90 weight percent polyhydroxyalkanoate (PHA) polymer or copolymer, based on the total weight of the fibrous filtration material. 3. The aerosol-generating article of claim 1 or claim 2, wherein the filter segment comprises at least about 95 weight percent polyhydroxyalkanoate (PHA) polymer or copolymer, based on the total weight of the fibrous filtration material. The filter segment further comprises at least about 5 weight percent, based on the total weight of the fibrous filtration material, of at least one biodegradable polymer, wherein the biodegradable polymer is starch, polybutylene succinate (PBS), polybutylene. Late adipate terephthalate (PBAT), thermoplastic starch and thermoplastic starch blends (TPS), polycaprolactone (PCL), polyglycolide (PGA), polyvinyl alcohol (PVOH/PVA), viscose, regenerated cellulose, polysaccharides, degree of substitution 4. Selected from the group consisting of cellulose acetate, polyamides, protein-based biopolymers, chitosan-chitin-based biopolymers, and combinations thereof with (DS) less than 2.1. The aerosol-generating article according to . 5. The aerosol-generating article of claim 4, wherein said filter segment comprises at least about 10 weight percent of said at least one biodegradable polymer, based on the total weight of said fibrous filtration material. 6. The aerosol-generating article of claim 4 or claim 5, wherein the filter segment comprises no more than about 15 weight percent of the at least one biodegradable polymer, based on the total weight of the fibrous filtration material. The aerosol-generating article of any one of claims 4-6, wherein the at least one biodegradable polymer is one or more of PBAT, PCL, and PBS. 8. The fibrous filtration material of any one of claims 1-7, wherein the fibrous filtration material comprises a plurality of fibers comprising a polyhydroxyalkanoate (PHA) polymer or copolymer and having a denier per filament of from about 1 to about 10. The aerosol-generating article described. 9. The fibrous filtration material of any one of claims 1-8, wherein the fibrous filtration material comprises a plurality of fibers comprising a polyhydroxyalkanoate (PHA) polymer or copolymer and having a denier per filament of from about 3.2 to about 5. 10. The aerosol-generating article described in Section 1. 10. The aerosol-generating article of any of claims 1-9, wherein the RTD of the filter segment is from about 35 millimeters _H2O to about 55 millimeters _H2O . 11. The aerosol-generating article of any of claims 1-10, wherein the RTD of the filter segment is from about 40 millimeters _H2O to about 50 millimeters _H2O . The aerosol-generating article of any one of claims 1-11, wherein the fibrous filtration material comprises crimped fibers comprising a polyhydroxyalkanoate (PHA) polymer or copolymer. The aerosol-generating article of any one of claims 1-12, wherein the length of the filter segment is from about 4 millimeters to about 27 millimeters. The aerosol-generating article of any one of claims 1-13, wherein the filter segment diameter is from about 5 millimeters to about 12 millimeters. A filter for an aerosol-generating article, said filter comprising a filter segment formed from a fibrous filtration material, said filter segment comprising at least about 85 weight percent, based on the total weight of said fibrous filtration material. A filter comprising fibers, wherein the fibers comprise a polyhydroxyalkanoate (PHA) polymer or copolymer.

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