DESC:FIELD OF THE INVENTION
The present invention relates to a method for producing aerosol-generating substrates containing reconstituted tobacco material and also to an aerosol-generating article containing substrates.

BACKGROUND OF THE INVENTION
Conventional cigarettes comprise a rod made of tobacco material (tobacco rod) with a wrapping made of cigarette paper. A cylindrical filter (plug) made of cellulose acetate with a wrapping made of filter paper (plug wrap) is placed on one end of the tobacco rod. The tobacco material, i.e. the substrate is made of natural leaf tobacco, in particular by conditioning, stemming/stripping, drying, mixing, saucing (casing), flavouring and cutting. Frequently, up to 25% reconstituted tobacco or other tobacco substitute is mixed into the tobacco material produced in this manner. Reconstituted tobacco is a pliant, homogeneous, paper-like sheet, which is produced in a process known from paper production of finely ground and rebundled raw tobacco or from clean fabrication waste also treated in this manner.
Alternatives like aerosol generating devices for delivery of nicotine such as electronic vaping devices and e-cigarettes have been introduced in the recent past. Even though these devices pose lesser health risks, they often fail to provide the desired consumer satisfaction. One possible reason can be their inability to deliver the desired tobacco taste/flavour to the consumer as compared to a conventional cigarette. Some of the existing electronic and/or carbon heat not burn products heat tobacco substrate to generate aerosol for meeting consumer requirements.
EP2844088 B1 discloses a smoking article with a tobacco substrate and its preparation process comprising steps of (a) combining tobacco with a gelling agent and a solvent to form a tobacco gel; (b) removing the solvent from the tobacco gel to form a tobacco substrate disposing the same in a molding element; (c) providing a plurality of elongate members through a length of the tobacco gel; wherein the tobacco substrate comprises a plurality of open channels that extend through a length of the tobacco substrate in the form of a rod element, (d) enclosing the tobacco rod in a wrapper to form a continuous wrapped (enclosed) rod and (e) cutting the continuous wrapped rod into individual rod portions. Such substrate has a tobacco density of about 150 mg/cm3 or less and a hardness of 60% or greater.
EP 3,075,266 discloses a method for producing aerosol-generating articles comprising the following steps: (a) making a sheet of reconstituted tobacco material, (b) cutting the sheet into shreds, (c) adding a tacky flavour to the tobacco material, (d) producing a continuous tobacco rod comprising shreds, enclosing the tobacco rod in a wrapper to form a continuous wrapped (enclosed) rod and cutting the continuous wrapped rod into individual rod portions. It discloses a packing density of 150 mg/cc to about 400 mg/cc.
WO2012164009 discloses rods comprising a gathered sheet of homogenised tobacco material for use in smoking articles, smoking articles comprising such rods and methods for forming such rods. Such sheets have average densities of about 430 mg/cm3.
US-A-4,000,748 discloses a process and apparatus for shredding a sheet of reconstituted tobacco into strips and crimping the resultant strips in a substantially simultaneous operation. The sheet of tobacco material is moved between a pair of rotating and intermeshing stacks of disks which shred the sheet into a plurality of strips about 0.65 to 1.55 mm in width. The forward motion of the resultant strips is retarded by engagement with facing surfaces of neighbouring disks causing a buckling of the strips into a crimped configuration. The crimped strips are reported to provide an increase in fill value.
US-A-4,889, 143 discloses cigarette rods having a plurality of substantially longitudinally extending strands provided from shredded sheet-like reconstituted tobacco material which are contained in a circumscribing wrapping material. Strips of sheet-like reconstituted tobacco material are shredded into a plurality of strands which are gathered into a rod-like shape and circumscribed by a paper wrap in order to form a continuous rod. The continuous rod is then severed at regular intervals to provide a plurality of rods of the desired length. The width of the strands is about 8 mm.
Cutting the sheet into strips of such less width of about 0.8 mm results in increasing the fill value and puts a limitation on the packing density. Packing at higher density will result in higher pressure drop of the rod. However, it has been found that higher widths of cut strips reduced pressure drop of the rod when packed at higher densities.
Unlike combustion in a conventional cigarette, these heat not burn products only releases nicotine and flavours without burning/consuming the tobacco rod. Heating a conventional cigarette rod at temperatures of around 350 to 450 0C will not provide the same deliveries as that by a conventional process of combustion. To deliver nicotine similar to that of a conventional cigarette from this material, obtained using conventional cutting process, the length of the tobacco rod has to be more than 20 mm which creates problems of disposal post consumption Thus, there remains a need for a process which would provide substrates and rods thereof having higher packing density yet having desirable end quality and draw effort.

OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to provide a process for preparation of a tobacco rod comprising an aerosol generating substrate, which involves the tobacco sheet being fed to the maker.
It is another object of the present invention to provide a process for preparation of an aerosol generating substrate involving said sheets being cut into strips of a width of at least 1.0 mm, followed by passing through a set of creasing rollers and collating such rolled strips to form the tobacco rod.
It is another object of the present invention to provide an aerosol generating substrate having a circumference of around 20.0 - 25.0 mm and a packing density ranging from about 450 mg/cc to 700 mg/cc.
It is yet another object of the present invention to provide an aerosol generating device comprising the said aerosol generating substrate.

SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
Accordingly in one aspect of the present invention there is provided a process for preparation of the tobacco rods comprising aerosol generating substrate, the process comprising the steps of:
Step 1: unwinding the recon sheet from recon bobbin

Step 2: passing the sheet through a set of creasing rollers to cut the sheet in form of strips

Step 3: collating the strips using a converging come to form a tobacco rodAccording to another aspect there is provided an aerosol generating substrate produced by the process as described herein above.
According to a further aspect there is provided an aerosol generating device comprising aerosol generating substrate produced by the process as described above.
Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

Brief Description of Accompanying Drawings
The features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are therefore not to be considered limiting of its scope the disclosure will be described with additional specificity and detail through use of the accompanying drawings.

Figure 1 shows the working principal of tobacco sheet unwinding and feeding system.
Figure 2 shows the device with peripheral heating source.
Figure 3 shows the device with a core heating source.

DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the scope of the invention as defined by the appended claims and their equivalents.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, steps or components but does not preclude the presence or addition of one or more other features, steps, components or groups thereof.
As used herein, the term 'rod' is used to denote a generally cylindrical element of substantially circular, oval or elliptical cross-section.
As used herein, the term 'sheet' denotes a laminar element having a width and length substantially greater than the thickness thereof.
As used herein, the term 'strip' denotes a longitudinal element having a length substantially greater than the width and thickness thereof.
As used herein, the term 'length' denotes the dimension in the direction of the cylindrical axis of rods according to the invention.
As used herein, the term 'width' denotes a dimension in a direction substantially perpendicular to the cylindrical axis of rods according to the invention.
As used herein, the term 'reconstituted tobacco material' denotes a pliant, homogeneous, paper-like sheet, which is produced in a process known from paper production of finely ground and rebundled raw tobacco or from clean fabrication waste also treated in this manner.

As used herein, the terms 'upstream' and 'downstream' are used to describe the relative positions of components, or portions of components, of smoking articles comprising rods according to the invention in relation to the direction of air drawn through the smoking articles during use thereof.
The present invention relates to a process for preparation of an aerosol generating substrate involving online creasing the reconstituted tobacco sheet to form cut strips and collating strips to form tobacco rod at extremely high densities.
The conventional process of preparing such substrates involved the tobacco being cut during primary processing and fed to maker in form of cut strands, followed by lifting using suction mechanism and transferred onto cigarette paper for rod formation. It suffered from the disadvantages of degradation of tobacco and random alignment of strands in the final rod.
The present process for preparation of the tobacco rods comprising aerosol generating substrate, the process comprising the steps of:
Step 1: unwinding the recon sheet from recon bobbin

Step 2: passing the sheet through a set of creasing rollers to cut the sheet in form of strips

Step 3: collating the strips using a converging come to form a tobacco rod
In the present invention the width of the strips varies from 1.0 mm to 40.0 mm depending on the width of the base sheet.
The Process of manufacturing is as follows:

The process involves by unwinding the tobacco sheets and passing it through the dancing roller system for tensioning and further there is a provision for heating the sheets before entering into creasing process. Throughout the process, the tobacco sheet shall be maintained at a requisite moisture level, ranging between 10-12%. Heating the sheets is an optional parameter. In case heating is required to maintain the moisture levels, it shall pass through the heating provision which is maintained at a temperature levels ranging between 80-120 deg C. As shown in Fig 1, the said sheet enters through the creasing/cutting rollers wherein the sheets are longitudinally cut and further enters for the rod making process, which is well known in the art.
The present inventors found that the cutting the reconstituted tobacco sheet into strips during the preparation process ensures almost 100% longitudinal alignment of strands in the final rod, enabling packing at very high densities without impacting draw effort and thus making it useful for heat not burn products is unique to the invention. It also ensures that the resultant rods on heating can deliver similar levels of nicotine as that of a conventional cigarette but with a shorter length.
The tobacco rods prepared by the present process have a circumference of around 20.0 - 25.0 mm and thus achieve extremely high filling densities or packing density, ranging from about 450 mg/cc to 700 mg/cc. As the conventional process involves preparing tobacco rods with a packing density achieved up to 450 mg/cc and beyond the said density values, this may increase/impact the pressure drop. Whereas, the present invention contemplates the density starting from 450 mg/cc and extends upto 700 mg/cc, preferably 650 mg/cc offers a desired aerosol generation, sensorial etc. and beyond the said values, it may affect the pressure drop.
In an embodiment of the present invention provides an aerosol generating devices comprising aerosol generating substrate prepared by the present process. Aerosol-generating device typically interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate forms a part of an aerosol-generating article, for example part of a smoking article. An aerosol-generating device may be a smoking device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is directly inhalable. It comprises an electric heating source, which is typically located upstream to the aerosol-generating substrate.
,CLAIMS:1. A process for preparation of an aerosol generating substrate for an aerosol generating article, the process comprising the steps of:
Step 1: unwinding the recon sheet from recon bobbin;

Step 2: passing the sheet through a set of creasing rollers to cut the sheet in form of strips;

Step 3: collating the strips using a converging come to form a tobacco rod,
wherein said substrate for an aerosol generating article further comprises a width ranging from 1 mm to 40 mm, higher pack densities ranging from about 450 mg/cc to 700 mg/cc, having a circumference ranging from 20.0 to 25.0 mm.

2. Process as claimed in claim 1, wherein the tobacco strips having width ranging from 1 mm to 40 mm so as to facilitate the longitudinal alignment of strands, enabling packing at very high densities.
3. Process as claimed in any of the preceding claims wherein the tobacco rods produced having a circumference ranging from 20.0 to 25.0 mm.
4. Process as claimed in any of the preceding claims wherein the tobacco rods produced having packing density ranging from 450 mg/cc to 700 mg/cc.
5. An aerosol generating substrate produced by the process as claimed in claims 1 to 4.
6. An aerosol generating device comprising an aerosol generating substrate as claimed in claim 5.
7. A substrate for an aerosol generating article, said substrate further characterized by reconstituted tobacco strips,
having a width ranging from 1 mm to 40 mm;
higher pack densities, ranging from about 450 mg/cc to 700 mg/cc,
having a circumference ranging from 20.0 to 25.0 mm.