Abstract
The inductively heatable tobacco product for aerosol-generation comprises an aerosol-forming substrate containing a susceptor in the form of a plurality of particles. The aerosol-forming substrate is a crimped tobacco sheet comprising tobacco material, fibers, binder, aerosol-former and the susceptor in the form of the plurality of particles.
Claims
1. An inductively heatable tobacco product for aerosol-generation, the tobacco product comprising: an aerosol-forming substrate containing a susceptor in the form of a plurality of magnetic particles, wherein the aerosol-forming substrate comprises tobacco material, fibers, binder, aerosol-former comprising glycerin, wherein sizes of the magnetic particles of the plurality of magnetic particles are in a range of about 5 micrometer to about 100 micrometer, wherein the plurality of magnetic particles amounts to a range between about 10 weight percent and about 40 weight percent of the tobacco product, and wherein the susceptor has a Curie temperature between 200 degree Celsius and 400 degree Celsius, the Curie temperature being a temperature at which the susceptor undergoes a phase change from a ferromagnetic phase to a paramagnetic phase.
2. The tobacco product according to claim 1, wherein the sizes of the magnetic particles of the plurality of magnetic particles are in a range of about 10 micrometer to about 80 micrometer.
3. The tobacco product according to claim 1, wherein the sizes of the magnetic particles of the plurality of magnetic particles are in a range of about 20 micrometer to about 50 micrometer.
4. The tobacco product according claim 1, wherein the magnetic particles of the plurality of magnetic particles are homogeneously distributed in the aerosol-forming substrate.
5. The tobacco product according to claim 1, wherein the tobacco product has a heat loss of at least 0.008 Joule per kilogram.
6. The tobacco product according to claim 5, wherein the heat loss is more than 0.05 Joule per kilogram.
7. The tobacco product according to claim 5, wherein the heat loss is more than 0.1 Joule per kilogram.
8. The tobacco product according to claim 1, wherein the plurality of magnetic particles amounts to 30 weight percent of the tobacco product.
9. The tobacco product according to claim 1, wherein the plurality of magnetic particles comprises a sintered material.
10. The tobacco product according to claim 1, wherein the plurality of magnetic particles is made of ferrite.
11. The tobacco product according to claim 1, wherein the tobacco material is homogenized tobacco material.
12. The tobacco product according to claim 11, wherein the tobacco material comprises tobacco particles having sizes in a range between 30 micrometer and 250 micrometer.
13. The tobacco product according to claim 1, having the form of a rod with a rod diameter in the range between 3 millimeters to 9 millimeters, and with a rod length in the range between 2 millimeters to 20 millimeters.
Description
(1) The invention is further described with regard to embodiments, which are illustrated by means of the following drawings, wherein
(2) FIG. 1 is a schematic drawing of a tobacco sheet with homogenized tobacco material and susceptor particles;
(3) FIG. 2 shows a temperature simulation of a tobacco plug made of a crimped homogenized tobacco sheet heated by a heating blade;
(4) FIG. 3 shows a temperature simulation of a tobacco plug made of a tobacco sheet according to FIG. 1 with uniform susceptor particle distribution;
(5) FIG. 4 shows a simulated glycerin depletion profile of the tobacco plug according to FIG. 2;
(6) FIG. 5 shows a simulated glycerin depletion profile of the tobacco plug according to FIG. 3;
(7) FIG. 6 shows simulated average temperature curves versus time of a tobacco plug heated with a heating blade and comprising uniform susceptor particle distribution, for example according to FIGS. 2 and 3.
(8) FIG. 1 schematically shows an aerosol-forming substrate in the form of a tobacco sheet 1. The tobacco sheet is made of homogenized tobacco particles 11 and preferably is a cast leaf as defined above and contains susceptor particles 10.
(9) The thickness 12 of the tobacco sheet preferably lies between 0.8 millimeters and 1.5 millimeters, while the size of the susceptor particles preferably lies between 10 micrometers and 80 micrometers. For forming the tobacco product according to the invention, the tobacco sheet 1 is crimped and folded to form a tobacco rod. Such a continuous rod is then cut to the required size for a tobacco plug to be used in combination with an inductive heating device for aerosol generation.
(10) FIG. 2 shows a view onto a simulated temperature distribution of a cross-section of a cylindrical tobacco plug 2 heated by a heating blade 20. The tobacco plug contains an aerosol-forming substrate made of a crimped tobacco sheet containing homogenized tobacco material and glycerin as aerosol former. The crimped tobacco sheet formed to rod shape is wrapped by a wrapper 23, for example paper. In the center of the tobacco plug the rectangular resistively heatable heating blade 20 is inserted for heating the aerosol-forming substrate. In FIG. 2 the temperature distribution has been simulated and is shown for heating the plug such that the core temperature is approximately 370 degrees C. in the center and as low as 80 degrees C. at the perimeter. Temperatures in a proximal region 220 of the blade 20 are as high as about 380 degree Celsius. Temperatures in intermediate 221 and distal, peripheral regions 222 are still as low as about 100-150 degree Celsius. Thus, according to the simulation measurement, intermediate and peripheral regions of the blade heated tobacco plug do not or only to a limited extend take part in aerosol formation—at least if the heating of the blade is limited to not completely burn the tobacco in the proximal region 220.
(11) This is also illustrated in FIG. 4. Therein, glycerin depletion of the tobacco plug according to FIG. 2 is shown. It can be seen that glycerin is entirely depleted in the proximal region 220 after five minutes of heating. No depletion has taken place in the peripheral regions 222, while the intermediate region 221 is partly depleted. Due to the rectangular cross-sectional shape of the heating blade, peripheral regions 222 with no depletion are limited to the parts of the plug, which are arranged next to the long sides of the blade 20. The proximal region 220 is arranged directly adjacent to the heating blade 20 and extends to maximal about ⅓ of the radius to each long side of the blade 20.
(12) FIG. 3 shows a view onto a simulated temperature distribution of a cross-section of an inductively heated cylindrical tobacco plug 3. The tobacco plug is made of a crimped tobacco sheet containing susceptor particles as described in FIG. 1. In the tobacco plug used for the temperature simulation 90 milligram FP 350 ferrite particles having an average size of 50 micrometers are evenly distributed in cast leaf made of a slurry of tobacco particles, fibers, binder and glycerin as aerosol former.
(13) The crimped tobacco sheet formed to rod shape is wrapped by a wrapper 13, for example paper. The susceptor particles are homogeneously distributed over the tobacco plug (not shown). The plug is heated via the inductively heated susceptor particles. In FIG. 3 the temperature distribution has been simulated and is shown for heating the plug with a more uniform temperature expected based on the homogeneously distributed susceptor particles within the plug. A temperatures in a central region 110 is about 300 degree Celsius. This circular central region 110 is rather large and extends to about half the radius of the tobacco plug. Temperatures in a narrow annular intermediate region 111 are about 250 degree Celsius and the temperatures of circumferentially arranged peripheral region 112 are about 200 degree Celsius. Thus, according to the simulation measurement, glycerin evaporates rather homogeneously and over the entire or substantially entire area of the tobacco plug. Glycerin is also evaporated from intermediate 111 and peripheral regions 112 of the tobacco plug. Thus, all areas of the tobacco plug are used for aerosol formation, even by maximal heating temperatures well below the ones known from centrally and resistively heated tobacco plugs.
(14) Glycerin depletion of the tobacco plug of FIG. 3 is illustrated in FIG. 5. It can be seen that glycerin is not yet entirely depleted, not even after five minutes of heating in the central region 110. However, some depletion has already taken place in the intermediate region 111 and to a lesser extent in the peripheral region 112.
(15) Temperature and glycerin depletion simulation of the plugs according to FIGS. 2 and 3 but heated for only about one minute and 1.5 minutes show the same relative temperature behavior. After 1 minute the tobacco plug according to the invention has already achieved a temperature of between about 150 and 200 degree Celsius over the central and intermediate region. Glycerin depletion has not yet commenced. After 1.5 minutes the temperatures have increased in inner peripheral region to about 200 degree Celsius to up to about 280 degrees Celsius in the central region. Temperatures as low as 150 degree Celsius are only present in the outer peripheral region 112. Thus, a glycerin depletion takes place over a large area of the tobacco plug already one to two minutes after starting to heat the tobacco plug.
(16) In contrast to the tobacco plug with susceptor particles according to the invention, a temperature distribution of the tobacco plug according to FIG. 2 with heating blade is almost identical to the one shown in FIG. 2 already after 1.5 minutes of heating. After 1.5 minutes of heating, the proximal region 220 has temperatures already as high as 380 degree Celsius and temperatures as low as about 100 degree Celsius in the intermediate and peripheral regions. After 1 minute of heating only a very small proximal region around the heating blade 20 is heated to about 200 degree Celsius. The remaining regions have slightly elevated temperatures or are still at room temperature.
(17) In FIG. 6 the average temperature T in the tobacco plug volume of the plug according to FIG. 1 and FIG. 3 versus time t is depicted. Line 35 indicates the temperature curve of the tobacco plug with susceptor particles according to the invention and line 25 indicates the temperature curve of the tobacco plug heated with heating blade. Maximum heating temperature of the heating blade was limited to 360 degree Celsius, while a Curie temperature of the susceptor in the tobacco plug according to the invention was between 350 and 400 degree Celsius. It can be seen that in the plug with the homogeneously distributed particles the average temperature rises much faster and slowly approaches a maximum average temperature of about 250 degree Celsius. The average temperature of the blade heated tobacco plug takes a bit longer to raise. The maximum average temperature in the blade heated plug lies at around 220 degree Celsius. No higher average temperatures may be reached due to the peripheral regions not being heated by the heating blade.
