DESC:Field of the invention
The present invention relates to a banded substrate which is to be used in various applications including smoking articles (LIP paper), personal care, flavors/fragrances, foods, pharma and the like. The present invention further relates to a method of making the same.
Background of the invention and prior art
A low ignition propensity (LIP) paper is designed to self-extinguish if left unattended. While a smoker is smoking an ignited cigarette, a burning cone of the ignited cigarette needs to be maintained. However, if the ignited cigarette falls onto a combustible object such as a floor may be due to the smoker's carelessness, free combustion of the ignited cigarette may cause burning of the combustible object. Hence in tobacco industry, development of a so-called low ignition propensity paper can hold down the risk of ignition of a combustible object.
Generally, LIP paper is being made using both online and offline coating technologies.
Offline coating defines a process where the coating is applied on the paper separately and the coated paper is used for manufacturing cigarettes. The coating formulation is generally applied in the form of a band at regular distance on the cigarette paper. Alginate is the material which is widely known in off line coating technology for making LIP paper. As this kind of coating is made off-line, flexibility of changing the band width and band position to meet the specific requirement of a segment of cigarettes including taste and smoking perception is limited.
Online coating defines a process where the coating is being applied on the paper while cigarette is being manufactured. Online coating technology generally uses raw materials such as starch and maltodextrin. However, starch is well known for its adhesive property and stickiness which needs to be handled more carefully. If not, it might tend to cause serious issues in terms of machine runnability and associated operational issues. Additionally, it might also interfere with the improper band formation which would result imparting poor smoke characteristics. Yet another challenge in using starch is to be used at lesser quantity because of its inherent stickiness property. In addition to that, starch is associated with “retrogradation” problems meaning, settling of starch molecules which further leads to cake formation which is considered to be a challenge.
Further, starch is unsuitable when it is used in high speed online coating applications. Because starch is sensitive to high shear force, and when operated at such high force, starch molecule tends to break which further leads to change in the viscosity and resulting in serious operational issues.
In this regard, various attempts have been made in the art (WO2015141919, US20150013707) to alter or modify the cigarette wrappers in order to achieve the desired tendency of the cigarette to self-extinguish, control the burn rate or in other words to reduce the ignition propensity characteristics of cigarettes.
US 20070246055 relates to a smoking article includes a smokable rod manufactured using a paper wrapping material having an additive material applied thereto as a pattern. The additive material is applied as coating formulation (e.g., an aqueous coating formulation) incorporating (i) inulin and guar gum, (ii) inulin and a polymeric material such as hydroxypropylcellulose or an alginate, or (ii) guar gum and a polymeric material such as hydroxypropylcellulose.
US ‘055 claims the use of a combination of inulin and other polymer such as guar gum along with other inorganic material and thickeners to develop low solid high viscosity formulation for LIP paper. The formulation preparation also claims requirement of heating and stirring for hours. People skilled in the art of coating knows that uniform coating on high speed online coating machine requires low viscosity and higher solid content; the higher the solid content and optimum the viscosity the better the coating uniformity and faster the drying. The present invention found that a low molecular weight guar gum which can be used to prepare aqueous solution of lower viscosity at very high solid content suitable for uniform coating at higher machine speed. A uniform coated LIP paper is required to make cigarettes which can pass the burning strength test as per the ASTM E 2187-09. ASTM International is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. In which, ASTM E 2187-09 provides guidelines to test the cigarettes burning strength. The burning strength can be defined as the ratio of the cigarettes not burnt to the end but extinguish in the middle among 40 pieces of cigarettes which are placed in a deck of 10 filter paper. It should be at least 75 % to claim the cigarette as fire safe.

Article published in NCBI entitled “Recent Advances in Cigarette Ignition Propensity Research and Development” mentions the use of guar gum on page 4. The paragraph reads as “Various designs for reducing ignition propensity incorporate in the paper wrapper burn altering chemical additives, which can either accelerate or retard burn rate, such as potassium citrate and other alkali metal salts, metals, or metal oxides [24] or permeability reducing constituents, such as additional paper, cellulose [25,26], or aqueous film-forming solutions (e.g., alginate, starch, tapioca, carrageenan, guar gum, pectin) [27,28], or various other polymers”.
The above Reference 28 discloses a composition suitable for gravure printing which may include polymers consisting of starch, alginate, carrageenan, guar gum, pectin, calcium carbonate, and citrates. It also claims application of the formulation on paper at elevated temperature and subsequently cooling the applied formulation for gelatinization. The patent also claims multiple number of printing of the formulation on the paper to get the desired thickness. People skilled in the art of coating and printing knows that heating of water based formulation for printing and cooling and repeating the steps in successive printing stations to get the desired thickness will not be feasible as these leads to many disadvantages such as change in viscosity of the printing solution, deposition on the rollers and rupturing of the paper.
The present invention is not confined to gravure printing and neither require heating of the formulation nor cooling for gelatinization and thus this prior art is not relevant in this context.
US 4489738 relates to self-extinguishing cigarettes and concerns the use of specific coatings that are applied to the paper wrapper that encloses the cigarette's smoking medium for limiting in a predictable manner the free burning time of the treated cigarette, or controlling the lapsed time prior to self-extinguishment after being lit and left unattended.
This prior art claims the use of film-forming adhesive selected from the group consisting of locust bean gum, pectin, guar gum, and sodium carboxymethyl cellulose and the aqueous film forming composition/formulation has a solid content around 2 %. Since the formulation contains very high volume of water, the prior art also discloses the requirement of air drying followed by oven drying for hours.

The present invention disclose a higher solid and low viscosity guar gum based composition/formulation suitable for high speed online coating application and requires very less time for drying.

However, none of the prior arts addresses the said problems in terms of offering a composition/formulation in making of LIP paper, made suitable for high speed online coating applications.

Objects of the invention
An object of the present invention is to overcome the drawbacks of the prior art.
It is an object of the present invention is to provide a coating composition/formulation to obtain a substrate atleast one banded region having a differentiated permeability and/or diffusivity than that of the non-banded region, made using a suitable, rated speed, online maker machine.
Another object of the present invention is to provide a substrate without altering the texture of the paper and give better aesthetic appeal to the consumable product such as low ignition propensity (LIP) paper for cigarettes/smoking article with or without filters, cigars, cigarillos, roll you won (RYO), smoking articles comprising wrapper, products having flavor inserts and the like.
It is another object of present invention is to provide a formulation for LIP paper with low viscosity and higher solid loading.
Another object of the present invention is to provide a water based formulation for LIP paper with a fast hydrating polymer having a stable viscosity at high solid content.
Yet another object of the present invention is to provide a LIP paper which does not impact any discernible machine runnability.
Yet another objective of the present invention is to manufacture cigarettes on high speed making machine with the coating formulation online.
Yet another objective of the present invention is to manufacture cigarettes with the LIP coating which conforms the burning strength requirement.
Yet another objective of the present invention is to provide a coating which does not alter the smoking characteristics of the smoke.
Yet another objective of the present invention is to manufacture cigarette with online coating for different segments of cigarettes (97 mm, 84 mm, 74 mm, 69 mm, 64 mm and the like).
Yet another objective of the present invention is to manufacture cigarettes of different circumference (e.g. 24.75 mm, 24.5 mm, 20 mm, 18 mm and the like) with LIP paper.
Both the length of filter rod and the length of tobacco column varies based upon the segment it cates to. Commercially available cigarettes have length in the range of 64 mm to 97 mm with a filter rod ranging from 15 mm to 27 mm and having the tobacco column length in between 49 mm and 72 mm.

One objective of the present invention is to manufacture low ignition propensity smoking article having different length and circumference.

Brief Description of Accompanying Drawing:
Figure 1: Schematic illustration of cigarette according to the present invention.
Figure 2: Schematic representation of a cigarette making machine and possible modification to coat the paper at the time of manufacturing cigarettes for the present invention.
Figure 3: Graphical illustration of the evaporation rate of the formulation as mentioned in the example.
Detailed Description of Present Invention
The present invention is related to the development of a formulation/ composition having selective polymers having high glass transition temperature based and a method of applying the formulation/composition on tobacco wrapping paper at the time of manufacturing smoking article. The present invention is also related to development of a smoking article having reduced ignition propensity with the coated paper.

The LIP paper for cigarette making with a formulation for high speed online coating application of the present invention has a high speed of 10000 cigarettes per minutes.

The present invention directs that formulation/composition having selective polymers having high glass transition temperature can be coated on cigarette paper as intermittent bands of certain width and cigarettes made with this paper shows reduced ignition propensity.

In fact, the invention also found that addition of composition/formulation having some selected polymers, preferably polymers having high glass transition temperature and more preferably polymers having glass transition temperature above the drying temperature of the paper improves drying efficiency of the coating. Example of polymers that can be used include and not limited to dextrin, maltodextrin, hemicellulose, tamarind seed gum and its derivative and a mixture thereof. Such polymers are commercially procured from Sigma Aldrich.

The present invention also directs that use of inorganic fillers, salts and monohydric alcohols helps to regulate viscosity and rheology of the coating solution.

Example of inorganic fillers which can be used include and not limited to nano-clay, nano-silicate, bentonite, MMT, calcium carbonate, zeolite and a mixture thereof. The present invention directs that these inorganic fillers acts as rheology modifier. A small percentage of the nano clay can increase viscosity significantly. Nano clays are known to reduce permeability and diffusion properties.

Example of monohydric alcohols which can be used include ethanol, iso-propyl alcohol and the like. The invention directs that a mixture of water and alcohol can be used as solvent for the coating formulation. Use of a mixture of water and alcohol is known to improve drying efficiency.

Example of salts which can be used include monovalent or divalent water soluble salts such as potassium chloride, sodium chloride, calcium chloride, or mixture thereof.

The names of the polymers, fillers, alcohol and salts disclose in the present invention are for example only and not limiting the scope of the invention.

Further, the formulation/composition of the present invention and the method also address the drawbacks of the prior art.

Guar gum is a polysaccharide of galactomannan family. It is consisting of mannose backbone whereas a galactose unit is liked to every second mannose unit, forming a short side-branches. Lower viscosity and lower molecular weight guar gum can be manufactured, for example, by enzymatic hydrolysis of the guar gum. Low viscosity guar gum can be manufactured through other processes, such as physical, thermal and chemical treatment. People skilled in the art knows that commercially available guar gum of various viscosity range can be produced by controlling the processing conditions.

The viscosity and the molecular weight of guar gum may vary to suit the coating equipment and the application procedure. However, the viscosity of the guar gum used in the present invention shall have 12 % viscosity in the range of 10-50 cps, molecular weight in between 20,000-50,000 dalton and glass transition temperature not less than 50 °C.
The inventors of the present invention found that guar gum having low viscosity and lower molecular weight alone can be applied as bands on the tobacco wrapping paper and cigarettes made with the paper has lower ignition propensity. The inventors found that when the drying temperature was increased above the glass transition temperature of guar gum for faster drying and higher rate of cigarette manufacturing, the coating composition/formulation turned into a sticky mass which inhibited further drying. The inventors found that inclusion of other polymers which have glass transition above the drying temperature of the coated paper can help to increase drying temperature which on the other hand can help in faster drying and higher rate of cigarette manufacturing.
The inventors have also found that inclusion of other inorganic fillers, water soluble salts and alcohol can assist in formation of uniform film and faster drying.
In a typical example, the preparation of the coating composition/formulation starts with dispersion of nano-clay in mixture of water and ethanol under vigorous agitation. The nano-clay have an aspect ratio not less than 100. The nano-clay may be present from about 0.01 to 2 %, preferably from 0.05 to1 % and more preferably from 0.1to 0.5 %. Ethanol may be present from about 5 to 30 %, preferably from 10 to 25 % and more preferably from 15 to 25 %. Potassium chloride is added once the homogenous has formed. Potassium chloride may be present from 0.5 to 5 %, preferably from 1 to 5 % and more preferably from 1.5 to 3.5 %. A mixture of low viscosity guar gum, maltodextrin and tamarind seed gum is added to the aqueous suspension at moderate agitation speed. The presence of all three are not critical but presence of all three definitely enhancing the performance. The selective polymer having high glass transition temperature comprises low viscosity guar gum, maltodextrin, tamarind seed powder in the ratio of 1:0.1:0.2 to 1:1:5.

The low viscosity guar gum and tamarind seed powder are present in the composition/formulation in the ratio of 1:1 to 1:0.1.

The low viscosity guar gum and maltodextrin are present in the composition/formulation in the ratio of 1:0.2 to 1: 4.

The selective polymers having high glass transition temperature is combined with the filler materials selected from the group comprising bentonite, montmorillonite, precipitated calcium carbonate and the like in the ratio of 1:0.01 to 1:0.25.

The selective polymer having high glass transition temperature is combined with the monohydric and dihydric water soluble salts, selected from the group comprising sodium chloride, potassium chloride, calcium chloride di hydrate and the like in the ratio of 1:0.05 to 1:0.25.

The selective polymer having high glass transition temperature is combined atleast one non aqueous solvent selected from ethanol, iso-propyl alcohol and the like in the ratio of 1:0.1 to 1:0.25.

In the coating formulation, the low viscosity guar gum having 12 % viscosity in the range of 10 to 50 cps may present from about 5 to 60%, preferably from 10 to 40 % and more preferably from 10 to 30 %. The low viscosity guar gum used may have glass transition temperature not less than 50 °C, preferably not less than 65 °C and more preferably not less than 75 °C.
In the coating formulation, maltodextrin having dextrose equivalent not more than 10, preferably not more than 5 and more preferably not more than 3 may be present as an ingredient. The maltodextrin used in the present invention may have glass transition temperature not less than 100 °C, preferably not less than 150°C and more preferably not less than 200 °C. For example, the maltodextrin used in one of the formulation has dextrose equivalent 2 and glass transition temperature around 210 °C. Maltodextrin may be used from about 5 to 60 %, preferably from 7.5 to 50 % and more preferably from 10 to 30%.
In this formulation, tamarind seed gum having 5 % solution viscosity from about 10 to 50 cps at 25 °C may be present as another ingredient. The tamarind seed gum used in the present invention may have glass transition temperature not less than 120 °C, preferably not less than 150°C and more preferably not less than 200°C. The tamarind seed gum may be used in the present invention from about 2 to 30 %, preferably from 3.5 to 20 % and more preferably from 5 to 15 %.
The amount of solid content in the formulation may range from 25-45% with viscosity which is workable in the coating system, not more than 3000 cps. Solid content can be defined as the (Total weight of the solid component) / (Total weight of the formulation).
The present invention is also related to the process of converting any tobacco wrapping paper of any porosity into a paper which reduced ignition propensity of the smoking article made with the paper. The process comprises steps of:
(a) supplying a base web to form a substrate for smoking article with atleast one band;
(b) applying a coating composition/formulation onto the substrate using a coating machine selected from direct rotogravure coating machine, off set rotogravure coating machine, flexo machine and the like and dried before it enters the maker machine;
wherein said banded region having a differentiated permeability/diffusivity than that of the non-banded region;
distance between the said bands having atleast 2-10 mm each;
each of the said band having 2-10 mm of width.
The present invention is also related to application of the low viscosity guar gum based formulation/composition on the tobacco wrapping paper as discrete area at the time of manufacturing the smoking article.

The present invention is also related to a method of application of the formulation/composition on the wrapping paper and manufacturing smoking article with it. In accordance with the present invention, the low viscosity guar gum based formulation is applied on the tobacco wrapping paper as discrete areas at the time of manufacturing the smoking article. The present invention found that the low viscosity guar gum based formulation and the method of coating and drying of the formulation at the time of manufacturing the smoking article can manufacture smoking article without any defects, at the rated speed of the manufacturing machine and the smoking article made with the formulation and the method shows low ignition propensity behavior when tested as per the standard.

For the purpose of ease of explanation, the present invention will be discussed in regards to cigarette and not to limit the spirit and scope of the present invention to cigarette only. Any other form and design of smoking article will fall under the sprit and scope of the present invention.

For the purpose of understanding, the present invention has illustrated a log ignition propensity cigarette in Figure-1. The low ignition propensity cigarette (1) includes a tobacco rod section (2) where the cut tobacco is wrapped with a wrapping paper and a filter rod section (3). The tobacco rod and the filter rod are attached with the help of a tipping paper. Cigarettes without the filter rod are also available. Commercially available cigarettes have different tobacco rod length and filter rod length. The paper wrapping the cut tobacco may have different permeability. For example, commercially available cigarettes having tobacco rod length of 57 mm have paper permeability around 40 CU whereas cigarettes having tobacco rod length of 54 mm have paper permeability around 80 CU. The low ignition propensity cigarette according to the present invention has two identical coated areas (4,5) separated by untreated areas. The permeability and gas diffusion coefficient of the coated areas are lower than the untreated areas. The coating, in the present invention is done as discrete bands. In the present invention, the discrete bands are defined as treated areas across the circumference of the tobacco rod.

The width of the band can be different based upon many factors including the permeability and gas diffusion coefficient of the untreated paper, the density and the circumference of the tobacco rod. It is known that if the density of the tobacco is less, the energy required to burn any combustible surface by the lit tobacco will be less. Also, if the permeability of the untreated wrapping paper is very low, the rate of burning the tobacco may be low and the heat energy generated during burning the tobacco might not be sufficient enough to combust any substance if the lit cigarette is placed on any combustible surface. Moreover, it will be disadvantageous if the lit cigarette extinguishes in the hand of the smoker at the time of not actively puffing due to very low permeability and coefficient of gas diffusion. The width of the band can be from 2 mm to about 10 mm.

The length of the untreated area and the distance between the treated area is generally designed in such a way that the untreated area shall not dissipate enough heat energy to burn a substance. In most of the commercially available low ignition propensity cigarettes, the spacing between the bands is 20 mm and the length of the untreated area from burning end (6) and filter end (7) varies depending upon the position of the bands on the tobacco rod.

It is understandable that thickness of the coated area will vary based upon the permeability of the untreated paper. In general, higher thickness of the coating is required if the untreated paper has higher permeability and the vice versa.

Figure-2 illustrates the commercially available cigarette manufacturing machine and the schematically illustrating a possible modification of the machine to make it suitable the present invention.

In general, any cigarette manufacturing machine comprises and tobacco rod formation area (1) and a filter attachment area. The tobacco rod formation area has a source of cut tobacco and a wrapping paper supply section. The wrapping paper passes through a series of rollers and guides which maintains the tension and position it requires. In a typical scenario, the cut tobacco is wrapped by the wrapping paper and an adhesive supply section applies adhesive on the seam of the paper. A heating arrangement dries the adhesive and the tobacco rod is formed. In the present invention, an off-set rotogravure coating applicator (2) and a plurality of heating system (3,4) are installed to coat the wrapping paper at the time of manufacturing cigarettes. The off-set rotogravure coating applicator has a coating material reservoir (5) and a plurality of rollers. the pick-up roller (6) picks up the coating material from the reservoir and transfers to the transfer roller (7). The transfer roller transfers the coating patches to the wrapping paper (8). A compression roller (9) presses the paper on the transfer roller for uniform transfer of the coating material on paper. The heaters dry the wrapping paper. An attachment to twist the paper to bring the coated side facing the cut tobacco can be installed, if required.

EXAMPLES:

Example 1: Design of low ignition propensity cigarettes

Table-1illustrates a harmonized design of the low ignition propensity cigarettes across different segments of cigarette available commercially. The design is to explain the invention and is not to limit the scope of the invention. Other design of the cigarettes harmonizing across the segments are also possible.

Table-1: Design of low ignition propensity cigarettes for different segments:

Length, mm
(1) Rod length, mm
(2) Plug length, mm
(3) Segments (in mm) as per Figure-1
7 5 8 4 6
84 27 57 12 5 19 5 16
74 15 59 12 5 21 5 16
69 15 54 12 5 16 5 16
64 15 49 12 5 11 5 16

Further, cigarettes were made with coating the formulation on 80 CU paper as per the below design:
Cigarette length: 84 mm
Tobacco rod length: 57 mm
Tobacco rod circumference: 24.75 mm
Plug length: 27 mm
Number of bands: 2
Band width: 5 mm
Band position: 24 mm from burning end; 12 mm from plug end.
Density: 247-253
Ventilation: 15 %
Example 2: Composition and viscosity of the coating formulation
Table-2 discloses examples of the coating formulations and viscosities of these coating formulation.
Table-2: Composition and viscosity of the coating formulation.
Formulation Ingredients Viscosity
(cps)
Guar gum Maltodextrin Tamarind seed gum Nano-clay Potassium chloride Ethanol Water
A 57.5 0 00 00 00 00 70 1431
B 70 00 00 00 7 7 70 2249
C 20 25 9 0.4 00 20 70 1450
Table-2 shows that even though formulation “A” and ‘C’ have different solid content but their viscosities are almost same.
Example 3: Method of making LIP paper

The following example illustrate the making of LIP paper step by step.
Step-1: Making of the coating formulation and feeding in the coating assembly.
Step-2: Running the coating assembly to ensure uniform film formation on the pick-up and transfer roller.
Step-3: Press the running paper on the transfer roller through pneumatic system to transfer the coating bands from transfer roller to the paper.
Step-4: Pass the coated paper through different drying system to dry the paper before it enters the tobacco rod formation area.
Example 4: Effect of low molecular weight guar gum.
Table 3
Guar gum Viscosity range Remark
Low viscosity 10 % viscosity 20-100 cps Run well on the coating machine. Formulation has higher solid content. Dries faster.
Medium viscosity 1 % viscosity 500-1000 cps Could not make formulation with higher solid content. The coating takes longer time to dry. Coating with multiple defects.
High viscosity 1 % viscosity 5000-8000 cps Could not run with such high viscosity.

Example 5: Effect of solid content and viscosity in the formulation.
Table 4
Solid content (%) 20 min viscosity 24 Hrs. viscosity Remark
25% 125 cps 140 cps Higher penetration. Paper rapturing, defects, too long drying time.
35% 286 cps 358 cps Higher penetration. Paper rapturing, defects, too long drying time.
40% 587 cps 720 cps Working well.
45% 1431 cps 1500 cps Working well
50% 4795 cps 4950 cps Coating is not uniform, observed flacking of coating material post drying.

Example 6: Comparison of LIP paper comprising starch/other polymers (non-working) with guar gum (working example)
Starch having an inherent property of retro-gradation. The lower the viscosity of starch, the higher the chances of retro-gradation. Starch also has a shear thinning property. At higher operating speed it breaks the starch molecules resulting non-reversible change in viscosity which in return changes the coating performance. This limits use of starch alone in coating.
Table 5
Formulation Viscosity (cps)
20 rpm 100 rpm 400 rpm 600 rpm 1000 rpm 1200 rpm 1400 rpm
Guar gum based 2270 1098 875 814 754 746 741
Starch based 2505 1150 751 432 311 145 85

Example 7: Viscosity (cps) of coating composition over time
Table-6 discloses change in viscosity of the formulations over time. Table-6 directs that the polymers used in this formulation develops optimum viscosity faster and the viscosity does not increase significantly over time. This indicates that unlike starch based coating solution mentioned in the prior art which suffers retro gradation, guar gum based coating formulation has stable viscosity over time and does not suffer retro gradation.
People in the known of coating technology knows that change in viscosity is highly disadvantageous in high speed coating application.
Table-6: Viscosity (cps) of coating composition over time:
Formulation Viscosity (cps)
20 min 2 Hrs. 4 Hrs. 24 Hrs.
A 1431 1495 1503 1504
B 2249 2267 2300 2302
C 1450 1455 1488 1510
It is generally observed that the viscosity of the coating solution decreases with increase in shear rate and the behavior of the coating solution at the applied shear rate effects the coating operation for example, if the viscosity is very low the coating solution can penetrate more and weaken the wet web strength which may result into snapping of the paper and longer duration of drying time. On the other hand, if the viscosity of the coating solution is more, formation of uniform film formation would be difficult. Table-7 shows that behavior of the formulation of the present invention at different shear rate.
Example 8: Rheological characteristics of the coating composition
Table-7:
Formulation Viscosity (cps)
20 rpm 100 rpm 400 rpm 600 rpm 1000 rpm 1200 rpm 1400 rpm
A 1450 700 560 522 481 476 472
B 2270 1098 875 814 754 746 741
C 1450 1082 874 788 653 625 611
The inventors of the present invention have disclosed the use of 8-12 UP rollers to make cigarette at the rated speed of the machine. The invention directs that in the disclosed coating assembly, the incident of paper snapping is more and the drying is not complete at the rates speed if the viscosity of the coating solution at that shear rate is below 100 cps. The invention also directs that the chances of non-uniform coating formation and is more if the viscosity of the coating formulation at that shear rate is higher than 1000 cps. The invention directs that good quality coated paper can be produced at the rates speed of the machine if the viscosity of the coating formulation at that shear rate is in between 150 and 950 cps, more preferably in between 300 and 800 cps and more preferable in between 400 and 700 cps.
The present invention also directs the drying performance of different coating formulation on 80 CU cigarette paper. The result of Figure-3 indicates that the rate of evaporation is highest in Formulation-C which might be liked to higher glass transition temperature of the polymeric ingredients.
Permeability and gas diffusion coefficient of these cigarette papers with and without coating with are measured and disclosed in Table-8.
Table-8: Permeability and coefficient of gas diffusion:

Paper details Permeability (average) Coefficient of diffusion
Uncoated 80 CU 1.62
Coated with Formulation-A 15.3 0.11
Coated with Formulation-B 9.7 0.23
Coated with Formulation-C 12.9 0.16
The result directs that coating can substantially reduce both permeability and coefficient of gas diffusion of the paper. The extent of decrease of the permeability and coefficient of diffusivity might be controlled by altering coating thickness on the paper.
Example 9: Data regarding maintaining texture of paper.
LIP paper made with low solid content in the prior art experiences higher water loss during drying which results into shrinkage of the paper and change in the texture of the paper post drying. On the other hand, the formulation of the present invention has higher solid content i.e. lower water content hence does not shrink much and does not change the texture of the paper post drying.
Example 10: Data regarding machine run-ability.
The machine runnability was compared with Formulation-A and Formulation-C as illustrated in Table-9. We found that with only guar gum, the drying was slow and we could achieve drying rate which is equivalent to production of cigarettes at the rate of 5500 /min. On the other hand, formulation-c which is a mixture of guar gum and other increments could dry faster and can produce cigarette at a speed of 10000 per minutes without any defects.
Table 9
Formulation Ingredients Maximum runnability
(cig/min)
Guar gum Maltodextrin Tamarind seed gum Nano-clay Potassium chloride Ethanol Water
A 57.5 0 00 00 00 00 70 5500/min
C 20 25 9 0.4 00 20 70 10000/min

Example 11: Burning behavior of coated and uncoated cigarette
The burning behavior of the cigarettes are tested and the result is disclosed in Table-10. The burning strength of the cigarettes is measured according to the method explained in ASTM E 2187-04. To explain the method briefly, a sample size of 40 cigarettes is used and the ratio of the cigarettes extinguish in between and the full length burn denotes the burning strength of the cigarettes. The higher the burning strength of the cigarettes the higher the chance of self-extinguishment of the cigarettes if left unattended on a combustible surface. Free air self-extinguishment (FASE) is also checked for the samples. Free air self-extinguishment (FASE) refers to the number of cigarettes extinguish when the cigarette is burnt in a static burning state. Study said that the higher the FASE, the more the chance of extinguishing the cigarette in the smoldering state which might result in discomfort to the smoker.
Table-10:
Paper details Sample size Extinguishing on holder Extinguishing at band Full length burn Burning strength FASE
Uncoated 40 0 NA 40 0 % 0 %
Coated with Formulation-A 40 0 32 8 80 % 0 %
Coated with Formulation-B 40 0 33 7 82.5 % 0%
Coated with Formulation-C 40 0 37 3 92.5 % 0%
Table-10 directs that cigarette made with these formulation shows burning strength above 80 %. The table also directs that the coating does not change the FASE value of the cigarettes thus might not extinguish during smoldering.
Cigarettes made with the coated and uncoated paper were subjected to cigarette quality checking and smoke sensory evaluation. Cigarette quality checking was aimed to find whether a smoker can identify the position of the band on the tobacco rod. A trained smoke panelist was used for both cigarette quality check and sensory evaluation. The test concluded that both the uncoated and coated cigarettes looks identical in terms of physical appearance.
The smoke sensory evaluation was done considering irritation of the smoke, aftertaste, flavor amplitude and overall acceptability as the key parameters.
Example 12: Criticality of ratio
The ratio of low viscosity guar gum to other components are critical as any deviation from the range would result into a coating formulation having different viscosity, rheological and drying rate which in turn may result into coating defects and processing difficulties.
For example, if the ethanol content in the formulation is higher, it could result into sedimentation of solids from the formulation.
Table 11
Formulation Ingredients Maximum runnability
(cig/min)
Guar gum Maltodextrin Tamarind seed gum Nano-clay Potassium chloride Ethanol Water
N 20 25 9 0.4 00 40 70 No uniform coating film formation happened

,CLAIMS:1. A substrate comprising;
atleast one banded region having a differentiated permeability and/or diffusivity than that of the non-banded region;
wherein said band is cast on the substrate at a pre-defined interval, made using a suitable, rated speed, online maker machine.
2. The substrate as claimed in claim 1, a substrate is a low ignition propensity paper for smoking articles such as cigars, cigarettes with or without filters, cigarillos, beedis, roll-your-own (RYO), sheet of paper, wrapper, flavor inserts, low smell smoke (LSS) type of smoking articles and the like.

3. The substrate as claimed in claim 2, wherein said pre-defined intervals of atleast one band is cast at 15 mm away from the burning end of the smoking article and the other band is cast at 10 mm away from the filter portion of the smoking article.

4. A coating composition to cast a band on substrate comprising;
a. atleast one selective polymers having high glass transition temperature;
b. atleast one filler material;
c. atleast one monohydric and dihydric water soluble salt;
d. atleast one non-aqueous solvent; and
e. optionally flavor compounds;
such that said composition casts band on the substrate at pre-defined intervals.
5. The coating composition as claimed in claim 4, wherein said selective polymer having high glass transition temperature is selected from guar gum, tamarind seed powder, maltodextrin and combinations thereof.

6. The coating composition as claimed in claim 5 wherein said selective polymer having high glass transition temperature comprises low viscosity guar gum and tamarind seed powder in the ratio of 1:1 to 1:0.1.

7. The coating composition as claimed in claim 5, wherein said selective polymer having high glass transition temperature comprises low viscosity guar gum and maltodextrin in the ratio of 1:0.2 to 1: 4.

8. The coating composition as claimed in claim 5, wherein said selective polymer having high glass transition temperature comprises low viscosity guar gum, maltodextrin, tamarind seed powder in the ratio of 1:0.1:0.2 to 1:1:5.

9. The coating composition as claimed in claim 5, wherein said selective polymers having high glass transition temperature is combined with the filler materials selected from the group comprising bentonite, montmorillonite, precipitated calcium carbonate and the like in the ratio of 1:0.01 to 1:0.25.

10. The coating composition as claimed in claim 4, wherein said selective polymer having high glass transition temperature is combined with the monohydric and dihydric water soluble salts, selected from the group comprising sodium chloride, potassium chloride, calcium chloride di hydrate and the like in the ratio of 1:0.05 to 1:0.25.

11. The coating composition as claimed in claim 4, wherein said selective polymer having high glass transition temperature is combined atleast one non aqueous solvent selected from ethanol, iso-propyl alcohol and the like in the ratio of 1:0.1 to 1:0.25.

12. A method of making a substrate, comprising:
a. supplying a base web to form a substrate with atleast one band;
b. applying a coating composition onto the substrate using a coating machine selected from direct rotogravure coating machine, off set rotogravure coating machine, flexo machine and the like and dried before it enters the maker machine;
wherein said banded region having a differentiated permeability/diffusivity than that of the non-banded region;
distance between the said bands having atleast 2-10 mm each;
each of the said band having 2-10 mm of width.
13. The method as claimed in claim 11, wherein said maker machine is smoking article making machine, paper making machine and the like.

14. The method as claimed in claim 11, wherein said maker is operated at a speed equivalent to linear length of 570 meters per minute.

15. The method as claimed in claim 11, wherein the method of making a substrate with banded regions, is suitable for a making any desired smoking article having different length and circumference.