Method of processing tobacco fines into a non-continuous tobacco material
A method of processing tobacco fines into a non-continuous tobacco material, the method including providing a pre-sized tobacco stem material that has a Dp90 particle size of less than 3 mm and a Dp50 particle size of less than 2 mm. The method also includes combining the pre-sized tobacco stem material with tobacco fines to provide a tobacco initial material, and processing the initial material by setting the initial material to a predefined increased moisture content, subjecting the initial material to an increase in temperature and subjecting the initial material an increased pressure in order to bind the tobacco fines to the tobacco stem material. There is also provided a non-continuous tobacco material produced by the method, a component for a delivery system including non-continuous tobacco material produced by the method, a product and a smoking article including the component.
1 . A method of processing tobacco fines into a non-continuous tobacco material, the method comprising:
providing a pre-sized tobacco stem material that has a Dp90 particle size of less than 3 mm and a Dp50 particle size of less than 2 mm;
combining the pre-sized tobacco stem material with tobacco fines to provide a tobacco initial material; and,
processing the initial material by setting the initial material to a predefined increased moisture content, subjecting the initial material to an increase in temperature and subjecting the initial material an increased pressure in order to bind the tobacco fines to the tobacco stem material;
feeding the processed tobacco material through a shearing gap such that the processed tobacco is defibrated by expansion, wherein the shearing gap is arranged between shearing surfaces, wherein a rotatable shearing member comprises one of the shearing surfaces, wherein the shearing member comprises a plurality of grooves, and wherein the grooves each have a maximum width of at most 2 mm.
2 . A method according to claim 1 , wherein the pre-sized stem material has a Dp90 particle size of less than 2.9 mm and, optionally, less than 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1 or 2 mm.
3 . A method according to claim 1 , wherein the pre-sized stem material has a Dp50 particle size of less than 1.9 mm and, optionally, less than 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1 or 1 mm.
4 . A method according to claim 1 , wherein the initial material further comprises winnowings.
5 . A method according to claim 1 , wherein the tobacco fines have a particle size smaller than 1 mm and, optionally, smaller than 0.5 mm.
6 . A method according to claim 1 , wherein the tobacco fines are bound to the pre-sized tobacco stem material mechanically, without using any externally applied binding agents.
7 . A method according to claim 1 , wherein the step of processing the initial material comprises conveying the initial material through a conveyor which builds up a mechanical pressure.
8 . A method according to claim 7 , wherein the conveyor comprises an extruder.
9 . A method according to claim 7 , wherein the conveyer is operated at a throughput of greater than 100 kg/hr.
10 . A method according to claim 1 , comprising pre-conditioning the stem material and/or winnowings to one or more of the following parameters: Temperature: 80-147 [deg.] C; Moisture: in the range of 6-14% OV by mass; and, Pressure (gas over-pressure): 0-8 bar.
11 . A method according to claim 1 , wherein processing the initial material comprises setting the initial material to a moisture content in the range 10 to 50% OV (oven volatiles) by mass.
12 . A method according to claim 1 , wherein processing the initial material comprises heating the initial material to a temperature in the range of 60 to 180° C.
13 . A method according to claim 1 , wherein processing the initial material comprises pressurising the initial material to a pressure in the range 10 to 200 bar.
14 . A method according to claim 1 , wherein the non-continuous tobacco material is a fibrous and/or granular material.
15 . A method according to claim 1 , wherein the tobacco initial material comprises in at least 30% pre-sized tobacco stem material (by mass).
16 . A method according to claim 1 , comprising exposing the processed tobacco material to a drop in pressure resulting in flash evaporation.
17 . A method according to claim 1 , wherein the shearing gap has a width in the range of 10 to 2000 microns.
18 . A method according to claim 1 , wherein the shearing member comprises at least 80 grooves.
19 . A method according to claim 18 , wherein the grooves each have a maximum width of at most 1.5 or 1 mm.
20 . A method according to claim 1 , comprising rotating the shearing member at an angular velocity of at least 10 rpm.
21 . A method according to claim 1 , wherein the non-continuous tobacco material has an average fiber diameter of less than 0.9 mm.
22 . A method according to claim 1 , wherein the non-continuous tobacco material has a density index in the range of 350 to 600 kg/m 3 .