AEROSOL-GENERATING ARTICLE HAVING BIODEGRADABLE FILTRATION MATERIAL

Abstract

There is provided an aerosol-generating article (10) comprising an aerosol-generating substrate (12) and a filter (14) in axial alignment with the aerosol-generating substrate (12). The filter (14) comprises at least one segment of filtration material formed of one or more sheets of a fibrous paper-like material. The fibrous paper-like material comprises a combination of hydrophobic fibres and hydrophilic fibres such that the fibrous paper-like material has a water contact angle as measured in accordance with TAPPI/ANSI T 558 om-15 greater than 90 degrees. Further, the fibrous paper material has a biodegradability in aqueous medium as tested in accordance with ISO 14851 (2005) of at least 90 percent of the maximum degradation of a cellulose reference item within 56 days of testing. In addition, the hydrophobic fibres comprise hydrophobic viscose fibres.

Claims

1. An aerosol-generating article comprising: an aerosol-generating substrate; a filter in axial alignment with the aerosol-generating substrate, the filter comprising at least one segment of filtration material formed of one or more sheets of a fibrous paper-like material, wherein the fibrous paper-like material comprises a combination of hydrophobic fibres and hydrophilic fibres such that the fibrous paper-like material has a water contact angle as measured in accordance with TAPPI/ANSI T 558 om-15 greater than 90 degrees and wherein the fibrous paper-like material has a biodegradability in aqueous medium as tested in accordance with ISO 14851 (2005) of at least 70 percent of the degradation of a cellulose reference within 56 days of testing, wherein the hydrophobic fibres comprise hydrophobic viscose fibres.

2. The aerosol-generating article according to claim 1 wherein the fibrous paper-like material has a water contact angle as measured in accordance with TAPPI/ANSI T 558 om-15 of between 95 degrees and 105 degrees.

3. The aerosol-generating article according to claim 1 wherein the fibrous paper-like material has a biodegradability in aqueous medium as tested in accordance with ISO 14851 (2005) of at least 90 percent of the degradation of a cellulose reference within 56 days of testing.

4. The aerosol-generating article according to claim 1 wherein the water absorbency of the fibrous paper-like material is greater than 180 seconds.

5. The aerosol-generating article according to claim 1 wherein the hydrophilic fibres and the hydrophobic fibres represent at least 50 percent of weight of the dry matter of the fibrous paper-like material.

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

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

8. The aerosol-generating article according to claim 1 wherein the hydrophilic fibres comprise plant fibres, softwood fibres, or cellulose fibres.

9. The aerosol-generating article according to claim 1 wherein the fibrous paper-like material has a basis weight of at least 25 grams per square metre.

10. The aerosol-generating article according to claim 1 wherein the segment of filtration material is formed of one or more gathered sheets of the fibrous paper-like material.

11. The aerosol-generating article according to claim 1 wherein the one or more sheets of the fibrous paper-like material are crimped.

12. The aerosol-generating article according to claim 1 wherein the fibrous paper-like material comprises a binding agent selected from the group consisting of polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), polyvinyl acetate (PVA), polyethylene, polypropylene, polyester, cellulose acetate, cellulose ester, alkyl succinic anhydride, a rosin, an acrylic copolymer, a modified starch, an hydrocolloid, and mixtures thereof.

13. A filter segment for use in an aerosol-generating article comprising a filtration material circumscribed by a wrapper, the filtration material comprising a sheet of fibrous paper-like material, wherein the fibrous paper-like material comprises a combination of hydrophobic fibres and hydrophilic fibres, wherein the fibrous paper-like material has a water contact angle greater than 90 degrees angle as measured in accordance with TAPPI/ANSI T 558 om-15 and a biodegradability in aqueous medium as tested in accordance with ISO 14851 (2005) of at least 70 percent of the degradation of a cellulose reference within 56 days of testing, wherein the hydrophobic fibres comprise hydrophobic viscose fibres.

Description

[0097] The invention will now be further described with reference to the following Examples and the accompanying Figures, wherein:

[0098] FIG. 1 is a schematic side cross-sectional view of an aerosol-generating article in accordance with the invention; and

[0099] FIG. 2 is a graph showing the results of biodegradation tests carried out on samples of the fibrous paper-like material for use in an aerosol-generating article in accordance with the invention, as explained in the Examples below.

[0100] An embodiment of an aerosol-generating article 10 in accordance with the invention is illustrated in FIG. 1. The aerosol-generating article 10 comprises a rod 12 of an aerosol-generating substrate and a mouthpiece filter 14 in axial alignment with the aerosol-generating substrate. The filter 14 is arranged downstream from the aerosol-generating substrate 12.

[0101] The filter 14 comprises a segment of filtration material formed of one or more sheets of a fibrous paper-like material in accordance with the invention prepared as will be described in more detail below. In more detail, in the segment of filtration material the one or more sheets of fibrous paper-like material are gathered and extend along substantially the entire length of the segment and across substantially the entire transverse cross-sectional area of the segment.

[0102] In addition, the aerosol-generating article 10 comprises a hollow cellulose acetate tube 16 and a spacer element 18 arranged between the rod 12 and the filter 14, such that all four elements are arranged sequentially and in coaxial alignment. All four elements are circumscribed by a same wrapper 20 to form the aerosol-generating article.

[0103] The rod of aerosol-generating substrate 12 has a length of approximately 12 millimetres and a diameter of approximately 7 millimetres. The rod 12 is cylindrical in shape and has a substantially circular cross-section. The filter 14 is substantially cylindrical in shape and has a substantially circular cross-section, has a length of approximately 7 millimetres and a diameter of approximately 7 millimetres.

EXAMPLE 1

[0104] Several examples of the fibrous paper-like material of the invention were made at laboratory scale and tested by industry standard techniques. The hydrophobic fibres were DANUFIL OLEA® viscose fibres manufactured by Kelheim Fibres GmbH. These fibres have a titre of 1.7 dtex (1.53 den) to 3.3 dtex (2.97 den), and a length of 5 millimetres. Various types of hydrophilic fibres were used, such as bleached or unbleached softwood fibres, or bleached cellulose fibres all having a SR degree of 15 degrees SR. To make the fibrous paper-like material, both types of fibres were mixed with water to obtain a slurry. The aqueous slurry thus formed was then deposited onto a porous forming surface of an inclined wire paper machine to form a wet paper. The wet paper was then dried at a temperature between 80 degrees Celsius and 100 degrees Celsius.

[0105] The composition and characteristics of five samples are shown below.

TABLE-US-00001 Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Hydrophobic 50 percent, 1.7 60 percent, 3.3 50 percent, 1.7 50 percent, 1.7 49.9 percent, 1.7 fibres (percent by dry weight, dtex) Hydrophilic 50 percent 40 percent 50 percent 50 percent 49.9 percent fibres (percent Bleached Bleached Unbleached Bleached Bleached by dry weight, softwood softwood softwood softwood cellulose type) fibres fibres fibres fibres fibres Basis weight 36 37 37 26 26 (grams per square metre) Porosity 18700 21500 11000 24600 16900 (CORESTA) Tensile 3110 2690 3200 2500 2830 strength MD (cN/30 millimetres) Tensile 1600 1075 1200 990 1120 strength CD (cN/30 millimetres) Capillarity Rise 0 0 0 0 0 (millimetres/10 minutes) Water drop >180 >180 >180 >180 >180 (sec) TAPPPI-T432 Water contact 94 116 103 84 Not measured angle (degrees)

[0106] Sample 5 contained, in addition, 0.15 percent by dry weight of alkyl ketene dimer, a sizing agent.

[0107] The Capillarity Rise of the paper sheet is measured in accordance with ISO 8787:1986.

[0108] The Water drop value corresponds to the time necessary for a drop of water to be absorbed by a sheet of the fibrous paper-like material as measured by TAPPI T432 of 1964.

[0109] For comparison, a fibrous paper-like material containing 100 percent by weight unrefined softwood fibres was similarly made and tested. This control paper exhibited a Capillarity Rise value of 96 millimetres/10 minutes and a water drop value of less than 2 seconds.

EXAMPLE 2

[0110] Filter elements made of fibrous paper-like material were subjected to an aqueous biodegradation test. The standard methodology described in ISO 14851—Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium was followed. The test determines the biodegradation of a test item under laboratory conditions caused by a conditioned sludge. In more detail, the test material is brought into a chemically defined liquid medium, essentially free of other organic carbon sources, and spiked with micro-organisms. During the aerobic biodegradation of organic materials in an aqueous medium, oxygen is consumed and carbon is converted to carbon dioxide. At regular intervals the amount of CO.sub.2 produced is determined by titration of the KOH solution which absorbs CO.sub.2. The biodegradation based on CO.sub.2 production is calculated as the percentage of solid carbon of the test compound which has been converted to gaseous, mineral C in the form of CO.sub.2.

[0111] Two test items and one reference standard were tested. The cellulose reference standard is microcrystalline cellulose powder which is suitable for thin layer chromatography (Avicel, FMC). Test item 1 was a smoked cigarette butt comprising tipping paper and a 26 gsm fibrous paper-like filtration material of the invention made of 50 percent by dry weight bleached softwood fibres and 50 percent by dry weight Danufil Olea viscose fibres at 1.7 dtex (1.53 den) and 5 millimetres length. The contact angle of this material in item 1 was found to be greater than 95 degrees. Test item 2 was a smoked cigarette butt comprising the same type of tipping paper and conventional non-woven cellulose acetate as the filtration material. The contact angle of the cellulose acetate in item 2 was 90 degrees. Both items 1 and 2 had similar length (27 mm) and similar diameter (7.7 mm). Both were cut into small pieces of less than 2 millimetres in size at the start of the test.

[0112] The test was performed in triplicate. At the start of the test, each one of 12 reactors was filled with the same amount of mineral medium and inoculum to obtain a test medium with a concentration of approximately 30 milligrams suspended solids/litre. The reference and test items were added directly to the reactors. One set of 3 blank controls were also included. The source of micro-organisms (inoculum) was a mixture of activated sludge, obtained from different wastewater treatment plants. The reactors were stirred and incubated at a constant temperature (21 degrees Celsius ±1 degree Celsius) in the dark for a period of 56 days.

[0113] After 14, 28, 42 and 56 days the biodegradation was determined by measuring the amount of CO.sub.2 that had been captured in the KOH solution during the test. See FIG. 2.

[0114] Table 1 shows the results after 56 days. ThCO.sub.2 (=theoretical CO.sub.2 production based on the % organic carbon and input of the sample), net CO.sub.2 production and biodegradation percentage of reference and test items at the end of the test.

TABLE-US-00002 Average bio- Relative bio- Experimental ThCO.sub.2 NetCO.sub.2 degradation Standard degradation series (mg) (mg) (percent) deviation (percent) Cellulose 38.3 33.6 87.8 2.8 100 reference standard Items 1 39.3 32.5 82.7 3.0 94.2 26gsm fibrous paper-like material Items 2 41.3 12.3 29.8 1.5 33.9 Cellulose acetate tow

[0115] The biodegradation pattern of item 2 comprising the fibrous paper-like material was similar to that of the reference standard cellulose. After 14 days, a biodegradation of 59.5% was reached. From then on the biodegradation rate started to slow down. After 28 days an absolute biodegradation of 78.0 percent ±3.1 percent was measured. At the end of the test (56 days) a plateau in biodegradation was reached at a level of 82.7 percent ±3.0 percent. On a relative basis, compared to the reference standard, a biodegradation percentage of 94.2 percent was calculated.

[0116] In comparison, the biodegradation of cellulose acetate-containing item 1 started almost immediately at a moderate rate, but levelled off from 14 days onwards. After 56 days, an absolute biodegradation of 29.8 percent ±1.5 percent was measured, or 33.9 percent on a relative basis compared to the pure cellulose reference standard.

[0117] From these results, it can be concluded that test item 1 comprising the fibrous paper-like material of the invention fulfilled the 90 percent biodegradability requirement within 56 days of testing.