KR20140065005A - Filter materials and uses thereof - Google Patents

Abstract

The present invention relates to a filter material comprising cellulose acetate and polylactide in a weight ratio of about 95: 5 to about 75:25, and to a filter (2) or filter element comprising such a filter material. The present invention also relates to a smoking article (1) comprising a filter material, a filter (2) or a filter element.

Description

FIELD MATERIALS AND USES THEREOF FIELD OF THE INVENTION [0001]

The present invention relates to a filter material. More particularly, the present invention relates to a filter material that can be used to filter smoke, such as cigarette smoke, generated by smoking articles. The invention also relates to a filter or filter element comprising a filter material, as well as to a smoking article comprising a filter material, filter or filter element.

Various materials have been proposed as filter materials for cigarette smoke. The cellulose acetate tow is a filter material commonly used in filters for smoking articles, which contributes to selective removal of the particulate phase and selected anti-volatile compounds. However, the cellulose acetate tow can be expensive compared to some other filter materials that can be used. It is also desirable to pursue the use of materials supplied from a sustainable source. Nonetheless, because cellulose acetate is the tow material established for cigarette filters, and because of the consumer acceptability and potentially any regulatory acceptance, any alternative filter material will have similar filtration characteristics and will have similar taste and mouthfeel characteristics To provide filtered smoke.

According to a first aspect of the invention, there is provided a filter material comprising cellulose acetate and polylactide in a weight ratio of about 95: 5 to about 75:25.

In a second aspect of the invention, there is provided a filter or filter element for a smoking article comprising a filter material according to the first aspect.

In a third aspect of the present invention there is provided a smoking article comprising a filter material according to the first aspect or comprising a filter or filter element according to the second aspect.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the embodiments of the invention may be more fully understood, embodiments thereof will now be described by way of illustrative embodiments with reference to the accompanying drawings.

1 is a schematic side view of a smoking article comprising a filter according to embodiments of the present invention.
2 is a schematic cross-sectional view of an arrangement of CA tow and PLA fibers in a filter or filter element according to one embodiment.
Figure 3 is a schematic cross-sectional view of the arrangement of CA tow and PLA fibers in a filter or filter element according to another embodiment.
Figure 4 is a schematic cross-sectional view of an arrangement of CA tow and PLA fibers in a filter or filter element according to a further embodiment.
Figure 5 is a schematic cross-sectional view of an arrangement of CA tow and PLA fibers in a filter or filter element according to yet another alternative embodiment.
Figure 6 is a schematic cross-sectional view of an arrangement of a CA tow and a nonwoven sheet of PLA in a filter or filter element according to one embodiment.
7 is a schematic cross-sectional view of an arrangement of nonwoven sheets of CA tow and PLA in a filter or filter element according to an alternative embodiment.
8 is a schematic cross-sectional view of an arrangement of a CA tow and a nonwoven sheet of PLA in a filter or filter element according to yet another embodiment.
9 is a schematic axial cross-sectional view of a smoking article having a filter comprising a filter material according to another embodiment of the present invention.
Figures 10 to 16 provide graphs showing experimental data from the studies described in the Examples.

In some embodiments, the present invention relates to a combination of cellulose acetate and a polylactide to provide a filter material. The filter material may be suitable for use in a filter or filter element, such as may be suitable for use in smoking articles and / or used in smoking articles.

In some embodiments, the filter material has a weight ratio of about 75:25 to about 95: 5, a weight ratio of about 75:25 to about 90:10, a weight ratio of about 75:25 to about 85:15, Weight ratio of cellulose acetate and PLA.

Experimental data discussed in detail in the examples demonstrate that the filter material of the present invention exhibits excellent filtration characteristics. It has also been found that the properties of filters made from such materials can be tailored to produce the desired smoke yield and filtration efficiency.

Cellulose acetate

Cellulose acetate (CA) is an organic ester used in many industrial applications in the form of films and fibers. CA is derived from cellulose using an acetylation process, its main properties being its hardness, excellent impact resistance, high gloss, transparency, pleasing texture, low static electricity and resistance to hydrocarbons. CA has been reported to be potentially biodegradable. The biodegradation rate of CA can depend on its acetyl-group substitution degree (DS). As the DS of the CA decreases, the rate of biodegradation increases. A CA having a DS of less than 2.1 is considered biodegradable whereas a CA having a DS of greater than 2.1 is only poor or slow biodegradable.

Cellulose acetate (CA) used in filter materials for inclusion in smoking articles often has a degree of substitution (DS) of about 2.5. This relatively high DS means that the CA is poorly biodegradable, but such a DS is chosen because it makes the CA soluble in a solvent such as acetone. The solvent solubility of CA makes it possible to process the material in a useful manner, such as solvent film casting and solvent fiber spinning, which is a process used to form fibers of the cellulose acetate tow commonly used in filters of smoking articles.

CAs used in smoking article filters can be treated with plasticizers. This includes applying a plasticizer (generally in liquid form) to the surface of the CA fiber by, for example, spraying a liquid plasticizer onto the CA tow. The plasticizer acts to bind adjacent fibers to each other at their contacts, thereby imparting sufficient hardness to the filter rod to make and use the cigarette. Thus, the materials added to the CA in this manner are generally referred to as plasticizers, but they actually act as binders or curing agents rather than plasticizers. Suitable plasticizers for this purpose include triacetin (glycerine triacetate), TEC (triethyl citrate) and PEG 400 (low molecular weight polyethylene glycols). The plasticized cellulose acetate tow is also known to improve the selective removal of some semi-volatile compounds found in smoking (e.g., phenol, o-cresol, p-cresol and m-cresol). For this effect, it is considered essential that the plasticizer be present on the surface of the CA fiber.

Because of the fiber-bonding effect of the plasticizer, the CA filter typically contains less than 10% by weight, often less than 7% by weight of plasticizer. It has been found that the inclusion of larger amounts of plasticizer has a detrimental effect on the cellulose acetate tow resulting in the formation of pores.

CAs of the type discussed above may be used in the present invention. The cellulose acetate may be in the form of fiber, for example, in the form of a fiber tow. In some embodiments, cellulose acetate having a degree of substitution of from about 2.1 to about 2.5, or about 2.5, may be used.

In some embodiments, the CAs included in the filter material may be modified to provide or enhance beneficial properties of the filtered smoke, such as biodegradability, filtration and / or taste characteristics.

For example, a cellulose acetate tow can be made from a composition comprising a combination of a CA and a plasticizer, wherein the plasticizer is incorporated and retained within the structure of the CA. The blend can be formed by solvent blending, wherein CA and the plasticizer are soluble in acetone or other suitable solvent, the blend composition is formed from solution, and includes intimate blends of CA and a plasticizer. Alternatively, the CA and the plasticizer may be melt blended.

In another example, the cellulose acetate tow can be prepared from a composition comprising a combination of cellulose acetate (which may be a CA blended with a plasticizer) and a water soluble polymer, and such blends are optionally commercialized. In some embodiments, such compositions may be water-dispersible and / or biodegradable. Suitable water soluble polymers include polyvinyl alcohol (PVOH), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methyl cellulose (MC) and ethyl cellulose (HEMA), xanthan and pullulan, or combinations thereof. Suitable compatibilizers include graft copolymers such as PLA-grafted water-soluble polymers and include reactive compatibilizers such as maleic anhydride-grafted polylactide (MA-g-PLA).

Polylactide

Poly (lactic acid) or polylactide (PLA) are biodegradable and biocompatible polymers. It is derived from renewable resources (eg corn, wheat or rice), which is biodegradable, recyclable, and compatible. In addition, PLA exhibits excellent processability. It can be processed by injection molding, film extrusion, blow molding, thermoforming, fiber spinning, and film forming.

The polylactide (PLA) used in the present invention can be produced by various synthetic methods, such as ring-opening polymerization of lactide or direct condensation polymerization from lactic acid. Any PLA grade may be selected for use in the present invention, and the molecular weight of the PLA may vary depending upon the desired properties and applications. In some embodiments, poly (L-lactide) (PLLA) may be desirable due to its determination beneficial for the production of fibers.

The filter material of the present invention may include various forms of PLA, including, for example, fiber form, fiber tow form, and / or one or more nonwoven sheet material form. The PLA may be present in one or more types of filter materials.

PLA  fiber

When the PLA is provided in a fiber form, the polylactide fiber may consist essentially of a polylactide in one embodiment.

The fibers may be prepared from PLA in a variety of ways, including, for example, solvent spinning processes or melt extrusion processes.

In some embodiments, the filter material has a weight ratio of about 75:25 to about 95: 5, a weight ratio of about 75:25 to about 90:10, a weight ratio of about 75:25 to about 85:15, Weight cellulose acetate fibers and PLA fibers.

PLA  Sheet

In some embodiments of the present invention, the PLA filter material may be in the form of a nonwoven sheet. The nonwoven sheet material can be used as a filter material, for example, in smoking articles in the form of a crimped sheet or a gathered sheet.

The nonwoven material is broadly defined as a bonded sheet or web structure by entangling the fibers or filaments mechanically, thermally, or chemically, or by a combination of two or more thereof. They tend to be flat-type porous sheets made directly from discrete fibers. They are not made by weaving or knitting, and do not require the fibers to be converted to yarns.

Thus, in one embodiment, the filter material according to the present invention may comprise a CA tow and at least one PLA nonwoven sheet. Both materials can be arranged to ensure that the resulting plug of filter material exhibits sufficient hardness and structural integrity to allow it to be incorporated into a smoking article using conventional high speed manufacturing machinery .

The sheet material may have certain drawbacks when used as the sole type of filter material. In order to achieve the desired structural stiffness when constructing a filter element from a nonwoven sheet material, the filter material must be packed very tightly, which means that this filter element has properties that are significantly different from those made with fiber tow . They exhibit greater resistance to the flow of smoke, resulting in higher pressure drops than conventional cellulose acetate tow filters, which makes the user more difficult to suck from smoking articles. Perhaps more significantly, it has been found that the smoke aspirated through such filter material has different taste characteristics as compared to the smoke being drawn through a conventional cellulose acetate filter material. Above all, the filter element comprising the nonwoven sheet material or paper as the filter material has been found to exhibit significantly less selective removal of the particulate phase and the selected semi-volatile compound than conventional cellulose acetate tow filter material.

In one embodiment in which the nonwoven PLA sheet material is included in the filter material, the sheet material comprises one or more plasticizers including PEG and / or triacetin and / or TEC. For example, the sheet material may comprise PEG, and either or both of triacetin and TEC. In one embodiment, the polyethylene glycol may be liquid at room temperature, such as PEG 400. In another embodiment, the polyethylene glycol may include high molecular weight polyethylene glycols, such as polyethylene glycols which are solid at room temperature. Such polyethylene glycols include PEG 600 or higher, preferably PEG 1000 or higher. These particular polyethylene glycols are attractive because they are solid or semi-solid at room temperature and their addition will not interfere with the structural integrity of the nonwoven sheet material. Additives that are liquid at room temperature may adversely affect the structural integrity and strength of the filter element in some situations where the filter material is a nonwoven sheet material, for example, they may soften the nonwoven material. For this reason, there may be a limit to the amount of such additives that can be included while still maintaining the stiffness and strength required for the sheet material.

Indeed, rather than weakening the nonwoven sheet filter material, the use of high molecular weight polyethylene glycols can actually increase the structural integrity and stiffness of the filter material. This provides additional flexibility when forming a filter or filter element with respect to the amount of filter material needed to achieve the desired hardness and stiffness. This will also enable the manufacturer to adjust the pressure drop of the filter element. This will enable the filter or filter element to be configured to have characteristics very similar to those of a typical CA filter element.

In addition, the selective removal of the semi-volatile compounds provided by the addition of PEG to the filter material is proportional to the amount of PEG contained. The flexibility of adding a larger amount of PEG, including high molecular weight PEG, means that the ability of the filter material to selectively remove anti-volatile compounds can be adjusted to the desired level.

In one embodiment of the present invention, the PEG is included on the nonwoven sheet material or on the nonwoven sheet material in an amount of up to 30 wt%, preferably up to 20 wt%, more preferably 5 to 10 wt% of the sheet . These values are determined by comparing the dry weight of the PEG-free sheet to the weight of the sheet containing the PEG additive.

The addition of TEC and / or triacetin has a different effect on the nonwoven sheet material. Surprisingly, it has been found that these additives have a beneficial effect on the taste and aroma of the smoke being drawn through the filter element. A common review of non-CA filter materials is that they tend to adversely affect the smoke taste. Triacetin and TEC have different effects on taste characteristics of smokers, and both additives can be added in different amounts to produce the desired smoke taste profile.

In conventional cellulose acetate tows used in filter materials, the amount of triacetin or TEC that may be included is limited by the effect these additives have on binding the fibers of the fiber material, wherein the amount of triacetin in excess of about 7% Thereby causing pores to be formed in the cellulose acetate material. In contrast, the amount of TEC and triacetin that can be included in the nonwoven sheet material or on the nonwoven sheet material is not very limited. In fact, when PEG, which is solid at room temperature, is also added, the effect of these liquid additives which make the sheet material uneven is minimized and can be up to 20% by weight or up to 30% by weight A sheet material in an amount of about 12% by weight may be preferred. These values are determined by comparing the dry weight of the sheet material with no additive to the weight of the sheet material including the additive.

Further additives including tobacco extract, glycerin, menthol, carbon fibers, and carbon particles and the like may be introduced into the nonwoven sheet material or onto the nonwoven sheet material. Such additives may be introduced into the sheet material during their manufacture or may be applied to the material after manufacture is complete.

In certain embodiments, the filter material may comprise a nonwoven sheet material having a thickness of greater than about 0.05 mm, preferably from about 0.06 mm to about 0.08 mm. The nonwoven PLA filter material may have a basis weight of from about 15 g / m ² to about 60 g / m ² , preferably from about 20 g / m ² to about 45 g / m ² .

Nonwoven PLA sheets can be made by any known process. For example, a spunbond sheet is produced by forming a web from extruded and spun filaments and then joining the fibers. During the web lamination process, the fibers can be separated by air jet or electrostatic. Bonding can be performed by imparting strength and integrity to the web and applying a heated roll or hot needles to partially melt the polymer and fuse adjacent fibers together. Spunlacing is another process that uses high-speed jets of water to strike the web with fibers tied together.

Filters and Filters Element

The filter element and filter according to the invention comprise a filter material according to the first aspect of the invention. Such filter elements and filters may be introduced into the smoking article.

Thus, the filter element and the filter according to the present invention can have a weight ratio of about 75:25 to about 95: 5, a weight ratio of about 75:25 to about 90:10, a weight ratio of about 75:25 to about 85:15, : ≪ / RTI > 20 by weight of cellulose acetate and PLA.

The cellulose acetate may be in the form of a tow. The PLA may be in fiber form, fiber tow form and / or one or more non-woven sheet material form.

1, for purposes of illustration, a smoking article 1 according to an exemplary embodiment of the present invention includes a filter 2 and a smokable material, such as a cylindrical rod 3 of cigarette, The cylindrical rod 3 of the smokable material is aligned with the filter 2 such that one end thereof is adjacent to the end of the filter 2. The filter 2 is wrapped with a plug wrap (not shown), and the smokable material rod 3 is bonded to the filter 2 by a tipping paper (not shown) in a conventional manner. The filter 2 is substantially cylindrical and has a mouth end 4 and a smokable material end 5. The filter 2 comprises a plug of filter material according to the invention comprising cellulose acetate fibers 6 and polylactide.

The plug of filter material preferably has a size and shape suitable to match the size and shape of the rod of the smokable material which should be attached to the final smoking article.

Although the illustrated smoking article 1 comprises a filter 2 having a single filter element or segment comprising a combination of cellulose acetate and a water-soluble polymer as described herein, other arrangements are possible. For example, the filter 2 may comprise multiple segments, for example, two, three or more segments, and some or all of the segments include the filter material according to the present invention.

A number of different filter arrangements for smoking articles are contemplated, including composite filters, which may have different filtration capabilities and / or different materials such as different filter materials and additives such as adsorbents and flavorants, And a plurality of individual filter elements or sections. The term "flavoring agent " as used herein refers to a material that can be used to form the flavor or aroma desired in the product if local regulations permit.

Where the filter material comprises PLA in the form of fibers, the CA tow and PLA fibers may be provided in the form of a homogeneous mixture, and such PLA fibers are dispersed throughout the fibers of the CA tow.

In an alternative embodiment, the PLA fibers are arranged in a tow, and the filter material comprises at least one PLA tow zone and at least one CA tow zone. Some possible arrangements of such zones are shown in Figures 2-5.

2, the filter plug 10 is comprised of a PLA tow 12 arranged as a central core surrounded by an outer layer of CA tow 11, Is surrounded by a wrap (14). In an alternative embodiment (not shown in the figures), the central core is composed of CA tow and the surrounding material is a PLA tow composed of PLA fibers.

In another embodiment, as shown in Figures 3 and 4, the PLA tow is provided in multiple regions. In Figure 3, the PLA tow 12 is provided as multiple zones surrounded by the CA tow. These zones are shown to have a circular cross-section, although other shapes may be used. The number, size and shape of the zones may vary. The region may extend longitudinally along the entire length of the filter plug, or just along a portion thereof. In FIG. 4, the PLA tow 12 is provided in a radially extended zone, and the CA tow 11 is located between these zones.

5, the PLA tow includes a tow layer 12 embedded within the CA tow 11 such that the layer of PLA tow 12 wrapped around the longitudinal axis of the filter is arranged in a spiral arrangement. . The PLA tow layer can be introduced into the filter plug in other ways.

According to some embodiments, the filter material comprises PLA in the form of a nonwoven sheet material in combination with CA tow. Several possible arrangements for this combination of PLA sheet and CA tow are shown in Figures 6-8.

6, the filter plug 10 is composed of a PLA sheet 13 packed to form a central core, and such a PLA sheet 13 is formed by a Surrounded by outer layers. The zones are shown to have a circular cross-section, although other shapes may be used. In an alternative embodiment, as shown in FIG. 7, the central core is comprised of CA tow 11, and the enclosed material is formed from one or more PLA sheets 13.

Alternative arrangements of sheet material and tow are also contemplated. For example, as shown in FIG. 8, the PLA sheet material 13 wrapped around the longitudinal axis of the filter may be arranged in a spiral arrangement. CA tow 11 is disposed between the laps of sheet material 13, which may be comprised of one or more sheets.

As a further example, as shown in FIG. 9, in the filter material of the present invention, the PLA and CA are arranged "in line" within the filter. In the figure, the filter 2 is comprised of segments of two sections in the form of a tow, a nonwoven sheet, or a combination thereof, one comprising a CA tow 21 and the other comprising a PLA 22. A portion of the adjacent smokable material rod 3 is also shown. The CA tow can be positioned adjacent to the rod of the smokable material with the PLA at the inlet-end of the filter, as shown in Fig. In alternative embodiments, this position may be reversed. The length of the segment of the section is different in the figure to reflect the ratio of CA to PLA of 95: 5 to 75:25.

However, in some embodiments, both the PLA and the CA of the filter material according to the present invention are provided in the same section or segment of the filter or filter element.

It is possible to fabricate a filter or filter element from a filter material as described herein using conventional processes, techniques and devices.

Some filter elements may exhibit a pressure drop of more than about 40 mm water at an air flow rate of 17.5 cm ³ / s per 0.1 g of filter material. They may also exhibit filtration efficiencies for particulate matter of mainstream tobacco smoke of less than about 15% per 0.1 gram of filter material.

In one embodiment, the filter material comprising CA tow and PLA may be the only filter material in the filter element or filter.

In another embodiment, the filter element comprising CA tow and PLA may be a part of a larger filter. In other words, the filter element may be a part of a composite or multi-component filter. The filter elements of the composite filter may be arranged in the longitudinal direction of each other with the end of each filter element adjacent to the next element. The composite filter may have 2, 3, 4 or more different or separate sections.

The composite or multi-component filter may comprise one or more filter elements according to the invention. Where there is more than one filter element according to the invention in a composite filter, suitably the filter elements may be positioned vertically next to each other or separated by another filter element.

Where the filter element is used as a composite filter, one or more other sections of the composite filter may comprise a biodegradable filter material, such as a crepe, crimping or gathering paper material. The one or more other sections may optionally comprise one or more additives, such as an adsorbent or flavoring material.

In yet another alternative embodiment, the composite filter may comprise a section forming a cavity containing the granular material.

In addition, the pressure drop and / or mechanical filtration efficiency of the filter plug section may be selected to achieve the desired smoking mechanics and filtration characteristics that may be required for the particular product design desired.

In a composite filter arrangement, the pressure drop of the filter plug / section may vary.

The filter element and / or a portion of the composite filter comprising such a filter element may comprise a catalyst. Advantageously, the catalyst promotes the conversion of carbon monoxide (CO) to carbon dioxide (CO ₂ ) over the vapor of smoke. It is highly desirable that the catalyst is highly selective for carbon monoxide. Preferably, the catalyst can be one of the group consisting of transition metal oxide, silica, alumina, zeolite, impregnated carbon, for example, carbon impregnated with metal.

In some embodiments, a portion of the tobacco-rod end of the filter may comprise a cavity containing an adsorbent and / or catalyst, or alternatively may comprise a smoke filtering material having an adsorbent and / or catalyst dispersed therein can do. Advantageously, the adsorbent can retain at least a portion of the vapor phase of the smoke.

Smoking article

The smoking article of the present invention comprises the filter material according to the first aspect of the present invention. The filter material may be in the form of a filter element or filter according to the invention attached to a rod comprising a filterable material (e.g., a cigarette). The smoking article may be a cigarette.

As used herein, the term "smoking articles" refers to tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not- Depending on whether or not it is possible to smoke, products such as cigarettes, cigars and cigarillos are included.

Thus, the smoking article may comprise a weight ratio of about 75:25 to about 95: 5, a weight ratio of about 75:25 to about 90:10, a weight ratio of about 75:25 to about 85:15, or a weight ratio of about 80:20 ≪ / RTI > acetate and PLA.

The cellulose acetate may be in the form of a tow. The PLA may be in fiber form, fiber tow form and / or one or more non-woven sheet material form.

The filter element and / or the filter comprising such a filter element may be attached to the wrapped rod of the smokable filter material by a conventional tipping overwrap to form a smoking article. The tipping overlap may be a ventilated or non-tilted overlap.

The filterable filter material may be a tobacco material or a tobacco substitute material. Preferably, the smokable material is a tobacco material. Suitably, the tobacco material comprises at least one of a stem, a lamina, and a tobacco dust. The tobacco material may include one or more of the following forms: Virginia or flue-cured tobacco, Burley tobacco, Oriental tobacco, . According to some embodiments, the smokable material comprises a combination of tobacco materials. For example, the smokable material may include 10-80% Virginia cigarette, 10-60% verrill cigarette, 0-20% orient cigarette, 0-20% regenerated cigarette and 0-30% bulge cigarette have.

In some embodiments, the filter material according to the present invention and / or the smoking material of the smoking article comprising the filter or filter element according to the invention may comprise or consist of cut tobacco, It may be a fried tobacco. The smoking material may comprise a recycled tobacco or tobacco substitute material.

Example

Experiments were conducted to study and illustrate the use of the filter chemistries of the combination of nonwoven PLA, cellulose acetate (CA) tow and nonwoven PLA, and of the different filter modified versions of the smoke chemistry and of the three filter plasticizers.

Nonwoven PLA was produced using a spunbond process. The basis weight of the sheet is 30 gsm and the thickness is 180 m.

1. Filter Manufacturing

The nonwoven PLA was converted to a filter rod using a paper filter process for pure nonwoven PLA and a combined material filter (CMF) filter process in the case of a filter made from a combination of nonwoven PLA and CA.

Table 1 shows the characteristics of a 132 mm filter rod (without plasticizer) made from nonwoven PLA:

Table 1

* Filtrona hardness measurement

Figure 10 shows the change in pressure drop (PD) as a function of sheet width. The filter rod length was 132 mm. Figure 11 shows the relationship between pressure drop and load weight. The filter rod length was 132 mm. "Corrected PD" means that the pressure drop is calculated for a circumference of 24.30 mm when the initial filter circumference is slightly different from 24.30 mm.

The result shows a linear relationship between the pressure drop and the weight of the filter rod. A comparison between the capability curve of the nonwoven PLA (FIG. 11) and the CAT's capacity curve (not shown herein) indicates that the weight of the filter rod at the same pressure drop is much higher in the case of nonwoven PLA. The weight of a filter rod (132 mm) made from a conventional CA tow is 807 mg.

The characteristics of the filter rod (132 mm length) made using various plasticizers are summarized in Table 2 (TA = triacetin, PEG = poly (ethylene glycol) and TEC = triethyl citrate). The filter rod was made from a nonwoven PLA web having a width of 250 mm. The hardness results indicate that none of the additives used acts as a binder. The filter rod hardness decreases as the amount of additive used increases (see Table 2).

Table 2

* Filtrona hardness measurement.

The characteristics of the filter (132 mm length) fabricated by combining nonwoven PLA and CA tow are summarized in Table 3. The filters were made using a combined material filter (CMF) process. The plasticizer used was triacetin (TA).

Table 3

* Filtrona hardness measurement.

2. Cigarette  Produce

The cigarettes were assembled using the filters mentioned in Tables 1 to 3 without any large processing problems. A conventional CA tow was used as a CA control.

3 Smoke Chemistry

3.1. Filtration efficiency

To evaluate the filtration efficiency of the new filters and controls, the cigarettes were smoked under ISO regulations in the ventilated vent area. Table 4 summarizes the effect of pressure drop on the smoke yield of cigarettes with different pressure drop PLA filters (without additive) and CA control.

Table 4

Table 5 shows the smoke yield of a cigarette having a PLA filter containing different additives compared to a conventional CA control. The additives were triacetin (TA), poly (ethylene glycol) (PEG) and triethyl citrate (TEC).

Table 5

Figure 12 shows the filtration efficiency results for PLA filters (with no plasticizer) at different pressure drops. The results show that the efficiency of the PLA filter in the case of NFDPM is similar to the CA control at about 71 mm WG PD.

Figure 13 shows the filtration efficiency in the presence of different additives using a conventional CA as a control. The results show that the nature of the additive has a small effect on the NFDPM filtration efficiency. Water filtration efficiency was significantly influenced by PEG and TEC compared to TA. One possible explanation is that the presence of such an additive can affect the hydrophilicity of PLA. The additives used do not show any significant effect on the nicotine filtration efficiency.

The smoke yield and filtration efficiency for the case of the filter made using the combined material filter (CMF) process are shown in Table 6 and Fig. 14, respectively. The filter composition is expressed as a percentage of CA / PLA (w / w). The results show that the NFDPM filtration efficiency is higher when the filter composition (CA / PLA) is 47/53 and much higher when the composition (CA / PLA) is 75/25. However, it should be noted that the pressure drop of the CMF filter and the filter weight (Table 3) are higher than the CA control (420 mm WG, 810 mg for 132 mm filter rod). (Filter characteristics are reported in Table 3).

Table 6

3.2. Filtration selectivity

To evaluate the filtration selectivity of the different filters, the cigarettes were smoked under ISO regulations in the vented vent, and Hoffmann analytes were measured under the same conditions for all cigarettes. Only phenolic compounds were considered in this study.

Table 7 summarizes the effect of different additives in the PLA filter on phenolic compound yield. (Filter characteristics are reported in Table 2).

Table 7

Figure 15 shows the effect of additives on the filtration of selected phenols using a pure nonwoven PLA filter as a control. The results are normalized to tar and are expressed as percentage differences from the CA control. The results clearly show that cresol and phenol are reduced in the case of phenol when using TEC, in particular as compared to PLA filters without additives. PLA filters have specific selectivity for catechol, hydroquinone, and resorcinol and do not appear to be significantly different from CA controls. Since these compounds are found on particulates, these results are consistent with particulate filtration theory.

In the case of CMF, the results show that the combination of PLA and CA shows increased filtration selectivity over 100% PLA filters, and the best results for phenol selectivity are obtained for filters with a CA / PLA composition of 75/25 lost. Table 8 shows phenol transfer using a combined material filter (CMF) compared to 100% PLA and a conventional CA control. The filter composition is expressed as a percentage of CA / PLA (w / w). (Filtration characteristics are reported in Table 3).

Table 8

Figure 16 shows the effect of filter composition on filtration selectivity. The results are normalized to tar and expressed as a percentage difference from the CA control. CA control is used as a reference.

As described above, the nonwoven PLA can be processed into a cigarette filter using a paper filter process, and a combination of nonwoven PLA and CA tow can also be combined to form a filter material.

The capacity curve indicates that a wide range of filters can be manufactured with different pressure drops depending on the width of the material. The weight of the filter made of nonwoven PLA is higher than that produced from CA tow at the same pressure drop. The additives TA, PEG and TEC do not act as binders to cure the nonwoven PLA in the filter. However, TA, PEG, TEC can be used as additives in PLA filters to improve the filtration selectivity to phenol.

The combination of nonwoven PLA and CA tow provided some advantages over PLA filters, such as increased hardness of the filter and increased selective filtration of phenol.

It will be appreciated that any feature of the invention discussed herein may be used with any other feature to eliminate any doubt. In particular, certain features in the claims may be used with any other feature of the claims.

The embodiments described above are configured to comply with applicable laws and / or regulations, such as, by way of non-limiting example, regulations relating to flavors, additives, emissions, and / or ingredients.

Many other variations and modifications that fall within the scope of the following claims will be apparent to those skilled in the art.

Claims (11)

A filter material comprising a cellulose acetate and a polylactide in a weight ratio of about 95: 5 to about 75:25. The filter material of claim 1, wherein the cellulose acetate tow and the polylactide are present in a weight ratio of about 80:20. 3. The filter material according to claim 1 or 2, wherein the cellulose acetate comprises a cellulose acetate tow. 4. The filter material according to any one of claims 1 to 3, wherein the polylactide comprises a fiber polylactide tow. The filter material according to any one of claims 1 to 4, wherein the polylactide comprises at least one nonwoven polylactide sheet. 6. The filter material according to any one of claims 1 to 5, wherein the cellulose acetate tow comprises a plasticizer. 7. The filter material according to any one of claims 1 to 6, wherein the polylactide comprises a plasticizer. The filter material according to claim 6 or 7, wherein the plasticizer is selected from the group consisting of triacetin, triethyl citrate, polyethylene glycol. 9. Filter material according to any one of claims 1 to 8, wherein the amount of plasticizer contained in the filter material is 0 to 20% by weight of the filter material. A filter or filter element for a smoking article comprising the filter material of any one of claims 1 to 9. A smoking article comprising the filter material of any one of claims 1 to 9 or comprising the filter or filter element of claim 10.

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