Field of the Invention:
The present invention relates generally to a biodegradable filter material/composition
useful for the purpose of air and smoke filtration. Particularly, there is provided a natural
polymer(s) based cigarette filter material/composition.
The filter material/composition advantageously possesses higher filtration efficiency and
self degradation efficiency.
Background and the prior art:
Cigarette smoking has been known to be practiced for thousands of years and there has
been a lot of concern about the hazardous effects of smoking that arises due to several
types of particles that are present in the smoke generated during smoking. These particles
are proven to be a potential cause for numerous diseases including fatal cancers,
respiratory malfunctions, immune system disorders and a lot more. In an attempt to trap
these harmful particles "filters" were introduced that would improve the quality of smoke
produced due to smoking. With the advent of science and modem technologies a galore
of new techniques has been implemented for the development of such filters.
A cigarette filter has the purpose of reducing the amount of smoke, tar and fine
particles inhaled during the combustion of a cigarette. Filters also reduce the harshness of
the smoke and keep tobacco flakes out of the smoker's mouth.
Cigarette filters are specifically designed to absorb vapors and to accumulate particulate
smoke components. Filters also prevent tobacco from entering a smoker's mouth and
provide a mouthpiece that will not collapse as the cigarette is smoked. Filters vary in
filtration efficiency, depending on whether the cigarette is to be "light" or regular.
One of the conventional filters used now a day is the cellulose acetate filter. Irrespective
of its popularity, it has been found that these filters are not very efficient in trapping all
harmful particles. The raw material for the manufacture of these cigarette filters
is cellulose. The cellulose is acetylated, dissolved and spun as continuous synthetic fibers
arranged into a bundle called tow, which is further plasticized, shaped, and cut to length
to act as a filter. Cellulose acetate is biodegradable only in certain chemical forms, such
as in the acetic acid ester form of cellulose. In most forms, the biodegradability of
cellulose acetate remains relatively low. Further, the biodegradation character of cellulose
acetate is most often dependent on the degree of substitution, or the number of acetyl
groups per glucose unit of the cellulose acetate molecular structure. For example, if the
degree of substitution of cellulose acetate is decreased, the biodegradation rate of
cellulose acetate is increased. These filters possess potential environmental threat as they
consume a lot of time to degrade (time ranges between 1-10 years) under natural
conditions. Also, cellulose acetate is quite expensive which poses a major constraint in
the practical use of same in the filter material.
The non-degradable litter generated by these filters is a worrisome issue, as they also
possess toxic effects (Register KM. 2000, Cigarette Butts as Litter, Underwater
Naturalist, Bulletin of the American Littoral Society Volume 25). These filters even can
prove more hazardous as they can deliver added toxic components in the mainstream
smoke and can have adverse effects rather than proving beneficial (Bradford H. 2011,
The intractable cigarette filter problem, Tob. Control, doi: 10.1136/tc.2010.040113).
Different techniques have been used that involve coating of different materials over the
cellulose fibers, while some make use of material property or affinity in order to trap
these harmful properties (Taniguchi et al. 2011, Cigarette filter material and cigarette
material, US Patent No. 7,942,154 B2).
In other attempts, holes have been made through the filters in order to reduce the tar
delivered through the smoke as it leads to increased ventilation (L T Kozlowski, R J
O'Connor, G A Giovino, C A Whetzel, J Pauly, and K M Cummings. 2006, Maximum
yields might improve public health- if filter vents were banned: a lesson from the history
of vented filters, Tob Control, doi: 10.1136/tc.2006.016501), but even this technique has
also not shown adequate efficiency. Even though a number of companies did adopt the
ventilated filters, but research revealed that these filters do not provide any better results
with respect to filter properties (L T Kozlowski, R J O'Connor. 2002, Cigarette filter
ventilation is a defective design because of misleading taste, bigger puffs and blocked
vents, Tob Control, doi: 10.1136/tc.ll.suppl_l.i40).
Numerous smoke filters have been developed for reducing the amount of nicotine, and
especially tar, present in cigarette smoke introduced into human organism. They may be
filters containing additives (e.g. active carbon, charcoal), promoting ventilation or
heating, or filters suitable for dispersing smoke. Such are described e.g. in US patents
Nos. 3,958,579; 3,882,877; 3,762,422. Their common drawback is that the air resistance
is significantly increased by the filter and thus their smoking is rather difficult.
WO200002561] discloses a cigarette filter which comprises a reagent essentially
containing at! east one reactive functional group covalently bonded to a non-volatile
inorganic substrate. Said reagent contains functional groups like 3-aminopropylsilyl
groups which can chemically remove the gaseous component of a smoke stream such as
aldehyde component. The filtering agent used in this Invention is synthetic and so does
not degrade easily.
On the similar lines, US 3882878 discloses a cigarette filter which comprises cellulose
acetate fibers along with a plasticizer agent in an amount of 3 to 10% by weight based
on the cellulose acetate fibers. The plasticizer could be a diacetate, dipropionate or
dibutyrate ester of 1,3-butylene glycol.
US 5622190 discloses a smoking filter which comprises a first filter plug having a central
core of a gathered corrugated web material and a peripheral layer of a cellulose acetate
tow filter material surrounding the central core.
US 20120103352 relates to a cigarette filter for selectively and efficiently removing a
phenol compound. The filter comprises a cellulose ester tow and a cellulose acetate
particle dispersed in the cellulose ester tow and the cellulose acetate particle has the
particle size not less than 90% by weight of the cellulose acetate particle passing through
a sieve having an aperture size of 1.7 mm but fail to pass through a sieve having an
aperture size of 0.10 mm.
Thus, in the current state of the art, cellular acetate based filter material is being
dominantly used for the preparation of filter material for the purpose of air and smoke
filtration. However, cellular acetate fibers suffer from the shortcomings of having poor
degradability characteristic and therefore it causes harm to the environment. The high
cost of cellular acetate poses a great concern to search for an economical alternative
suitable to be used in the smoke filters.
Therefore, there is a need of a natural polymer based filtering material which possess
high filtration efficiency, quick self degradation capacity and is environment friendly &
cost effective.
Objects of the Invention:
An object of the present invention is to provide a biodegradable polymer(s) based
filtering composition usefiil for filtering smoke or other chemical particles.
An object of the present invention is to provide a biodegradable polymer(s) based
filtering composition having an enhanced particle filtration efficiency as compared to the
cellulose acetate based filter material.
An object of the present invention is to provide a biodegradable polymer(s) based
filtering composition having about 100% degradability.
An object of the present invention is to provide a biodegradable polymer(s) based
filtering composition which has fast self disintegration capacity.
An object of the present invention is to provide a biodegradable polymer(s) based
filtering composition which helps in achieving the desired pressure drop while smoking.
An object of the present invention is to provide an economical biodegradable polymer(s)
based filtering composition.
These and other advantages of the present invention will become readily apparent from
the following detailed description taken in conjunction with the accompanying drawings.
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.
In order to achieve said object, the present invention provides a biodegradable filter
material/composition useful for air and smoke filtration. The filter material/composition
comprises a macroporous polymeric material wherein said polymeric material comprises
a first polysaccharide present in a range varying fi-om 2% to 6%(w/v) per 10.35 ml, a
second polysaccharide present in an approximate amount of 0.5% (w/v) per 10.35 ml, a
first cross linking agent present in a range varying from 1% to 5% (w/v) per 10.35 ml and
a second cross linking agent present in a range varying from 0.055% to 0.55% per
10.35ml of said filter material.
In another aspect of the Invention, there is provided a process for the production of a
biodegradable filter material useful for air and smoke filtration, said process comprising
steps:
a) Dissolving about 350 to 450 mg of a first polysaccharide in 4ml deionized
water followed by heating at a temperature range of SO'^C to 100*^C
for about 30 to 45 minutes to yield solution (A);
b) Dissolving about 35 to 75 mg of a second polysaccharide in 5ml deionized
water followed by heating at temperature range of 50V to 60*^0
for about 30 minutes to an hour to yield solution (B);
c) Mixing solution (A) with solution (B) followed by homogenization at a
temperature range of 5(fC to 60°C for about 30 minutes to an hour;
d) Maintaining the temperature of the solution resulting from step (c) to
about 45 to 50*^C and adding about 250 to 500 i^l of first cross linking
agent followed by the vigorous stirring of the solution for about 10 to 30
seconds.
e) Adding about 1ml of second cross linking agent to the solution resulting
from step (d) followed by the vigorous stirring of the solution for about 10
to 30 seconds to result into said biodegradable filtration material.
In another aspect of the Invention, there is provided a process of fabricating an object
comprising above said biodegradable filter material. The process of fabricating an object
comprises following steps:
a) Pouring the filter material/composition into a moulding object followed by
the treatment in a liquid cryostat at a temperature ranging from -15 to -20°C
for a period ranging from 5 to 10 hours;
b) Freeze drying the moulds resulting from step (a) for a period of about 16
hours.
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 the accompanying drawings:
The above and other aspects, features, and advantages of certain exemplary embodiments
of the present invention will be more apparent from the following description taken in
conjunction with the accompanying drawings in which:
Figure 1: Representation of Un-encapsulated 1(a), Encapsulated 1(b) MPM and MPM
fitted within a cigarette 1 (c), respectively.
Figure 2: SEM images of MPM filters.
Figure 3: FTIR representation of MPM
Figure 4. Graphical representation of particle analysis of MPM vs. cellulose acetate.
Figure 5: Elemental analysis of MPM
Figure 6: Stress vs. Strain curve of MPM.
Persons skilled in the art will appreciate that elements in the figures are illustrated for
simplicity and clarity and may have not been drawn to scale. For example, the
dimensions of some of the elements in the figure may be exaggerated relative to other
elements to help to improve understanding of various exemplary embodiments of the
present disclosure.
Detailed description of the invention:
The following description is of exemplary embodiments only and is not intended to limit
the scope, applicability or configuration of the invention in any way. Rather, the
following description provides a convenient illustration for implementing exemplary
embodiments of the invention. Various changes to the described embodiments may be
made in the function and arrangement of the elements described without departing fi-om
the scope of the invention.
Accordingly, the invention provides a biodegradable filter material appropriate to be used
as air and smoke filter. The filter material comprises advantageous characteristic of
having complete and quick degradability. The filter material also possess a surprising
feature of having high filtration efficiency as compared to a cellulose acetate based filter
material.
Particularly, the Invention provides a highly efficient cigarette smoke filter
material/composition by making use of specific Macroporous Polymeric Materials
(MPM). Generally, MPM are highly porous and are interconnected structures, which are
formed by crosslinking of different polymer(s) by using a crosslinker agent. The pore
8
morphology of these polymeric material is beneficial in providing the desired pressure
drop and also facilitates the efficient trapping of harmful tar particles that originate from
cigarette smoking.
Particularly, the selection of natural polymers is responsible for achieving the higher
capture efficiency of toxic components from smoke. The filter material comprises
optimized concentration of these macroporous polymer which were further evaluated by
a series of tests in order to investigate their potential as cigarette smoke filters.
The term "starch" as used herein refers to a naturally abundant nutrient carbohydrate,
(C6H10O5)n, found chiefly in the seeds, fruits, tubers, roots, and stem pith of plants,
notably in com, potatoes, wheat, and rice, and varying widely in appearance according to
source but commonly prepared as a white amorphous tasteless powder.
As used herein, the term "smoking article" includes smokeable products such as
cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded
tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-bum products.
Detailed Process:
Synthesis of macroporous polymeric materials (MPM) as smoke filters:
The biodegradable filter material/composition comprises macroporous polymeric
material. The macroporous polymeric material essentially comprises combination of
polysaccharide(s) and cross linking agent(s) in a synergistic manner which results into
increased filtration efficiency and high self degradation capacity of the resulting filter
material/composition.
The macroporous polymeric material comprises following components:
a) A first polysaccharide(s) present in a range varying from 2% to 6% (w/v) per 10.35 ml,
b) A second polysaccharide(s) present in an approximate amount of 0.5% (w/v) per 10.35
ml.
c) A first cross linking agent(s) present in a range varying from 1% to 5% (w/v) per 10.35
ml
d) A second cross linking agent(s) present in a range varying from 0.055% to 0.55% per
10.35ml of said filter material/composition.
The first polysaccharide is selected from a group comprising of naturally occurring
starch, hydroxyalkylated starch, starch esters, oxidized starch, plasticized starch,
hydrolyzed starch, gelatinized starch, grafted starch, crosslinked starch, transglycosylated
starch or like. However, in a preferable embodiment, the first polysaccharide comprises a
naturally occurring starch.
While, the second polysaccharide component is selected from a group comprising of guar
gum, xanthan gum, locust bean gum, carrageenan, gelatin, chitosan, agarose. In another
preferred embodiment, guar gum is utilized as the second polysaccharide component.
The first cross linking agent is Glyoxal with about 25% concentration while the second
cross linking agent is preferably CaO with about 0.02 M concentration. However, any
other chemical agent with similar characteristics as of Glyoxal might also be utilized for
this purpose and the Invention is further not restricted to use CaO as the source of
calcium and the second cross linking agent in the proposed filter material, instead any
other calcium source can also be used for the same purpose. CaO is mainly used as a
crosslinking agent, but it may be possible that it can act as an absorbent too.
The size of starch and guar gum ranges between 500nm-20micron. Further, the Starch
has been derived from potato and majorly comprises of amylodextrin only.
The current polymeric concentration is the optimized concentration. However, it is
always possible to change the %composition but it will have a direct effect on the bulk
properties of the material like average pore size, flow property, mechanical property.
Said filter has the surprising effect of achieving about 28.5% higher particle filtration
efficiency as compared to the conventional cellulose acetate. The data is well
substantiated by the henceforth defined experimental results. Figure 4 shows the
10
graphical representation of the smoke particle capturing efficiency. The filter material
also possess 100% degradability. The degradation study shows that the filter material is
reduced to half its original dimension after 24 hours and there is almost complete
degradability of the filters in less than a week. The details of the study is discussed in the
henceforth mentioned experimental results.
Another aspect of the Invention provides a process for the production of above said
biodegradable filter material. The process essentially comprises following steps:
a) Dissolving about 350 to 450 mg of a first polysaccharide in 4rhl deionized
water followed by heating at a temperature range of 80°C to 100°C
for about 30 to 45 minutes to yield solution (A);
b) Dissolving about 35 to 75 mg of a second polysaccharide in 5ml deionized
water followed by heating at temperature range of 50*^C to 60°C
for about 30 minutes to an hour to yield solution (B);
c) Mixing solution (A) with solution (B) followed by homogenization at a
temperature range of 50''C to 60°C for about 30 minutes to an hour;
d) Maintaining the temperature of the solution resulting fi-om step (c) to
about 45 to 50*'C and adding about 250 to 500 i^l of first cross linking
agent followed by the vigorous stirring of the solution for about 10 to 30
seconds.
e) Adding about 1ml of second cross linking agent to the solution resulting
fi-om step (d) followed by the vigorous stirring of the solution for about 10
to 30 seconds to result into said biodegradable filtration material.
Detailed process for the production of filter material:
Experimental Details:
For achieving the above said biodegradable filter material, firstly a starch solution is
made by dissolving approximately 350 to 450 mg of the starch in 4 ml de-ionized water
to make the solution (A). The solution (A) is heated at about 80 to 100°C for about 30 to
11
45 minutes in a circulated water bath with frequent stirring until solution becomes clear.
The clear solution of the mixture shows complete dissolution of starch molecules.
Further, solution (B) is prepared by mixing about 35 to 75 mg guar gum in 5 ml deionized
water and then the solution is heated at 50 to 60°C for about 30 minutes to an
hour to solubilize the guar gum and for ensuring that the viscosity of the resulting
solution is substantially reduced and remains constant.
The prepared starch solution i.e. solution (A) and the guar gum solution i.e. solution (B)
is mixed and placed on a magnetic stirrer with mild stirring in order to homogenize the
resulting solution.
The temperature of the magnetic stirring unit is maintained at 50 to 60°C and the process
is continued for about 30 minutes to an hour. After the polymer solution is homogenized,
the temperature of the stirring imit is reduced to about 45 to 50*^0. As the resulting
solution temperature reaches to about 45 to 50°C, thereafter about 250 to 500 |j.l of first
cross linking agent like glyoxal (25%) is fiirther added to the final solution of solution
(A) and solution (B).
The resulting mixture is then vigorously stirred for about 10 to 30 second and then about
1 ml of 0.02 M of second cross linking agent like CaO is immediately added to the
resulting solution followed by fast stirring for another 10 to 30 seconds. The CaO
solution was prepared by weighing 11.2 mg CaO and mixing it in 10 ml of water. From
this stock, 1 ml CaO has been used for the experiments. The stirring is done mechanically
using a vortexer in a speed of about 100-500 rpm. A magnetic stirrer or an agitator can
also be used at similar speeds.
Resultantly, a total volume of 10.35 ml is produced by mixing all the ingredients which
gives starch concentration of about 4% (w/v) and the guar-gum concentration of about
0.5% (w/v).
12
After the cross linkers are mixed thoroughly, the reaction mixture is immediately poured
into plastic moulds in the form of four syringes of 9 mm internal diameter and 2.5 ml
volume. The syringes are then placed into a liquid cryostat maintained at -20 °C and
allowed to freeze completely for a period of 5 to 6 hour. Here, the freezing temperature
may range between -15 to -20 °C while freezing time can also range between 5-10 hours.
The moulds are then placed in a freeze-dryer for a period of 16 hour until they are
completely dry and when there is no ice.crystals present. The samples are further kept at
room temperature for sometime before they can be used.
Experimental Results:
1. Scanning Electron Microscopy (SEM):
SEM analysis was performed by cutting the samples into circular discs of 8 mm diameter
and 2 mm height. It was ensured that the samples were completely dry. The samples were
gold coated using the Cressington sputter coater at a current of 40 mA for a period of 90
seconds. After coating the samples, the samples were placed in a desiccator until they
were examined in order to keep them moisture free.
Figure 2 (a, b) represents the control with no smoke. Figure 2 (c, d) represents trapped
particles when smoke was passed through MPM at 25 °C and 60% relative humidity. It is
evident from the images, that the harmful tar particles and other hydrocarbons have been
trapped within the pores of the MPM with high efficiency. On comparing the surfaces of
the control and test samples it can be noticed that the control samples have a smoother
surface as compared with the rough surface of the test samples. This is because a lot of
harmful tar particles have been trapped incase of the test samples that makes their surface
look rough.
2. FT-IR Spectroscopy;
Figure 3 shows Fourier transform infrared spectroscopy (FTIR) representation of MPM.
The peak indicated by the arrow at 1108 reveals the dissolution of the aldehyde of
13
Glyoxal in Hydroxyl group of Starch to form a hemiacetal by nucleophilic substitution.
This peak ensures cross-linking of starch with glyoxal.
3. Particle Analysis; Comparison between MPM and Cellulose Acetate:
Particle analysis was performed on the scanning mobility particle size machine at 25°C
and 60% relative humidity. The filters i.e. the MPM and cellulose acetate filter were
fitted within 69mm cigarettes and the cigarettes were placed in the test end of the
equipment in order to quantify the number of particles that emanated from the cigarette
smoke through both the filters. It was observed that the MPM performed atleast 10^ times
better than the conventional cellulose acetate filters when average number of particles
was calculated as shown in Figure 4 which shows the graphical representation of the
particle analysis of MPM vs. cellulose acetate. The X-axis represents the diameter of the
particles in the cigarette smoke and Y-axis represents the number of particles on the
logarithmic scale. The higher filtration efficiency of the filter material is the
advantageous feature of the present Invention.
4. Pressure Drop:
Comparison between MPM and Cellulose Acetate:
To analyze the back pressure of the filters, filters of different lengths were placed in the
test column of a pressure drop (Cerulean PD Express) machine in such a way that the
samples were completely sealed and it was ensured that no air could pass through the
sides. The flow rate from the air compressor was kept constant at 15 1/min and the
pressure maintained during the test was 60 psi. Different pressure drop readings were
taken as shown in table 1 above. Back pressure analysis revealed no significant difference
in pressure drop of cigarettes fitted with MPM vs. the conventional filter. In real use also
when cigarettes fitted with MPM were given to people for smoking, no difference in
pressure drop was observed by any person as compared to normal cellulose acetate filter
fitted cigarettes. This was observed randomly for all age group and gender for more than
14
100 numbers. The below table demonstrates the comparison of pressure drop values in
cellulose acetate filter vs. MPM filters.
FJiter Type
A
B
C
D
Cellulose Acetate
(Uu-Eiicapsulated)
Cellulose Acetate
(Encapsulated)
MPM
(Un-Eucapsulated)
MPM
(Encapsulated)
Filter Length
(III mm)
15
27
15
27
15
27
15
27
PresMire Drop
(In mmVVg)
37,8
51.3
Oiiiy Filter
53.1
63.7
Filter With
Cigarette
84.7*
94. r*
65.2
91.6
Only Filter
69.7
94.5
Filter With
Cigarette
94,2'
110.3"
*nie leiiath of the cigarette is 69 mm. * *The leusth of the cigarette is 88 mm.
5. Energy Dispersive X-Ray Analysis (EDAX)- Elemental Analysis
The elemental analysis was performed on equal cross section area for both control and
test filter samples. Results indicated about enhanced Carbon and Oxygen peaks incase of
the MPM samples with smoke confirming the presence of harmful tar and other
hydrocarbon particles. Figure 5 shows the elemental analysis of MPM. The EDAX
analysis was performed on both control MPM SEimples with no smoke and test MPM
15
samples that were subjected to cigarette smoke as shown in Fig. 5(a) and 5(b),
respectively.
6. Compressive Strength:
The compressive strength of the filter material was calculated on the Bose Electroforce
mechanical testing machine. The ratio of height and the diameter were kept same (8mm)
for all MPM samples. The compressive strength calculated from the graph was
approximately 84+15 kPa. After the yield point, the filter material exhibited brittle
characteristics and fractures were observed after 50% deformation. Figure 6 shows Stress
vs. Strain curve of MPM. The X-axis represents Strain and Y-axis represents Stress
experienced by the MPM filters during the mechanical testing. From these results, it can
be concluded that the MPM possess enough strength in order to be used as cigarette
filters and shows desired stability as filter.
7. Degradation Study
It was observed that MPM degraded at a remarkable rate and after 24hour it had reduced
to half its original dimension while no significant change was observed in the cellulose
acetate filters with and without smoke. Almost complete degradation of MPM filters has
been observed within less than one week in natural and wet environment. In natural and
dry environment, the filter material of MPM filters was quite stable. However, the same
was not observed in the conventional filters of cellulose acetate, which may take years for
complete degradation. This quick and 100% degradability of the filter material is the
advantageous feature of the present Invention.
Figure 7 shows the degradation study of MPM and Cellulose acetate Filter. Figure 7 (a,
b) represent the degradation rate of the two materials at two time intervals, T= 0 hour and
T= 24 hour. The filter length and diameter was kept the same in both MPM and Cellulose
acetated filter (15mm). From these results, it can be concluded that the MPM possess
enough strength in order to be used as cigarette fihers and shows desired stability as
filter.
16
The samples were placed in soil in order to see the degradation behavior under natural
conditions. The test samples represent smoke subjected MPM and Cellulose Acetate
filters, while the control included no smoke.
In another aspect of the Invention, there is provided a process of fabricating an object
comprising above said biodegradable filter material.
The process comprises following steps:
a) pouring said filter material into a moulding object followed by the treatment in a
liquid cryostat at about -15 to -20 °C for a period ranging from 5 to 10 hours;
b) Freeze drying the moulds resulting from step (a) for a period of 16 hours.
The aforesaid object is preferably a smoking article but not restricted to the same. The
smoking article includes any smokeable products such as cigarettes, cigars and cigarillos.
The freeze drying method used for the production of smokeable article helps
in achieving the chaimeled pores and high pore volume (as supported by SEM images)
which resultantly enables minimal resistance to the flow of smoke. Figure 1 shows
representation of Un-encapsulated 1(a), Encapsulated 1(b) MPM and MPM fitted within
a cigarette 1(c) respectively.
The present invention will be explained fiirther with reference to non-limiting
embodiments of the invention.
In an embodiment of the present invention, there is provided a filter material which is
more readily degradable than filter elements comprising a conventional cellulose acetate
filter material.
In another embodiment of the present invention, there is provided a filter material which
exhibits good filtration efficiency.
17
In another embodiment of the present invention, there is provided a filter material which
comprises macroporous polymeric material along with additives like mint, clove oil,
apple water etc. for facilitating better taste and better smoking experience.
In another embodiment of the present invention, there is provided a smoking article
comprising aforesaid filter material attached to the rod of smokeable material. The
smoking article may be a cigarette. The smokeable filler material may be tobacco
material or a tobacco substitute material. Preferably the smokeable material is a tobacco
material. Suitably the tobacco material comprises one or more of stem, lamina, and
tobacco dust.
The invention will now be explained with the help of following examples. However, the
scope of the invention should not be limited to these examples as the person skilled in the
art can easily vary the proportion of the ingredients and combinations.
Example 1:
About 370mg of the starch was dissolved in 4ml de-ionized water followed by heating at
90°C for about 40 minutes. Further 50 mg of the guar gum was dissolved in 5ml deionized
water and heated at 55*^0 for about 50 minutes and finally the starch solution and
guar gum solution was mixed at the temperature of 60°C. Thereafter, 290 nl of glyoxal
was added to the resulting solution followed by vigorous stirring of the solution for about
20 seconds. Further after, 1ml of calcium oxide is added followed by the vigorous stirring
of the solution for about 30 seconds to result into said biodegradable filtration material.
Example 2:
The smoke filter was fitted at the back of a number of cigarettes manually and many
regular smokers (around 100 nos.) were made to smoke and they hardly could notice any
difference in back pressure or taste of the cigarette smoke. Some smokers reported
lightness in the smoke taste.
18
Example 3:
After the filters were synthesized, the filters were cut into desired length. The filters were
manually fitted at the back of a number of cigarettes. The test samples were then placed
into the test inlet of a particle analyzer. After the machine was set to "tesf mode, the
cigarette was lit using a lighter and the machine simulated real smoking conditions. All
the particles emanating from the smoke and passing the filter barrier were counted
electronically by the machine until whole cigarette was used up. The result was compared
with that of the conventional cellulose filter by plotting a graph. The result revealed
better performance of the newly designed filter material.
Example 4:
In order to measure the back pressure of the synthesized filters, filters of different lengths
were cut. Some of the filters were even covered with paper in order to ensure that no air
could pass through the sides while some were fitted in the cigarettes. Every type of
sample was then placed in the test area of a cerulean PD express machine. The machine
was connected with a compressor as a source of air. The flow rate and pressure were
strictly controlled and monitored constantly. Incase of each sample, the machine was
turned on and the respective reading was carefiilly noted down. The procedure was
followed until all samples were tested.
ADVANTAGES OF THE INVENTION:
1. The biodegradable filter material has better particle(s) trapping efficiency (as
substantiated by the particle and elemental analysis)
2. The biodegradable filter material has enhanced particle filtration efficiency as
compared to the cellulose acetate based filter material.
3. The biodegradable filter material has about 100% degradability in a short time.
4. The biodegradable filter material has fast self disintegration capacity.
5. The biodegradable filter material has accurate mechanical strength to be used as a
cigarette filter.
6. The filtering material/ composition is economical.
19

We claim:
1) A biodegradable filter material useful for air and smoke filtration, said filter
material comprises a macroporous polymeric material wherein said polymeric
material comprises a first polysaccharide present in a range varying from 2% to
6% (w/v) per 10.35 ml, a second polysaccharide present in an approximate
amount of 0.5% (w/v) per 10.35 ml, a first cross linking agent present in a range
varying from 1% to 5% (w/v) per 10.35 ml and a second cross linking agent
present in a range varying from 0.055% to 0.55% per 10.35ml of said filter
material.
2) The biodegradable filter material as claimed in claim 1, wherein the particle
filtration efficiency of said filter material is increased by about 28.5% as
compared to cellulose acetate filter.
3) The biodegradable filter material as claimed in claim 1, wherein said filter
material degrades to half its dimension material after 24 hours.
4) The biodegradable filter material as claimed in claim 1, wherein said first
polysaccharide is selected from a group comprising of naturally occurring starch,
hydroxyalkylated starch, starch esters, oxidized starch, plasticized starch,
hydrolyzed starch, gelatinized starch, grafted starch, crosslinked starch,
transglycosylated starch or like.
5) The biodegradable filter material as claimed in claim 1, wherein said second
polysaccharide component is selected fi-om a group comprising of guar gum,
xanthem gum, locust bean gum, carrageenan, gelatin, chitosan, agarose.
6) The biodegradable filter material as claimed in claim 1, wherein said first cross
linking agent is glyoxal.
7) The biodegradable filter material as claimed in claim 6, wherein said glyoxal has
concentration of about 25%.
8) The biodegradable filter material as claimed in claim 1, wherein said second cross
linking agent is CaO.
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9) The biodegradable filter material as claimed in claim 8, wherein said CaO has
about 0.02 M concentration.
10) The biodegradable filter material as claimed in claim 1, wherein the size of said
first polysaccharide and second polysaccharide ranges from 500nm to 20 micron.
11) A process for the production of a biodegradable filter material useful for air and
smoke filtration, said process comprising steps:
a) Dissolving about 350 to 450 mg of a first polysaccharide in 4ml deionized
water followed by heating at a temperature range of 80*^0 to 100°C
for about 30 to 45 minutes to yield solution (A);
b) Dissolving about 35 to 75 mg of a second polysaccharide in 5ml deionized
water followed by heating at temperature range of 50°C to 60'^C
for about 30 minutes to an hour to yield solution (B);
c) Mixing solution (A) with solution (B) followed by homogenization at a
temperature range of 50''C to 60*'C for about 30 minutes to an hour;
d) Maintaining the temperature of the solution resulting from step (c) to
about 45 to 50^C and adding about 250 to 500 p.\ of first cross linking
agent followed by the vigorous stirring of the solution for about 10 to 30
seconds.
e) Adding about 1ml of second cross linking agent to the solution resulting
from step (d) followed by the vigorous stirring of the solution for about 10
to 30 seconds to result into said biodegradable filtration material.
12) The process as claimed in claim 11, wherein said first polysaccharide is selected
from a group comprising of naturally occurring starch, hydroxyalkylated starch,
starch esters, oxidized starch, plasticized starch, hydrolyzed starch, gelatinized
starch, grafted starch, crosslinked starch, transglycosylated starch or like.
13) The process as claimed in claim 11, wherein said second polysaccharide
component is selected from a group comprising of guar gum, xanthan gum, locust
bean gum, carrageenan, gelatin, chitosan, agarose.
14) The process as claimed in claim 11, wherein said first cross linking agent is
glyoxal.
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15) The process as claimed in claim 14, wherein said glyoxal has concentration of
about 25%.
16) The process as claimed in claim 11, wherein said second cross linking agent is
CaO.
17) The process as claimed in claim 11, wherein said CaO has about 0.02 M
concentration.
18) The process as claimed in claim 17, wherein the concentration of said CaO ranges
from 0.055% to 0.55%.
19) The process as claimed in claim 11, wherein the size of the first polysaccharide
and second polysaccharide ranges from 500nm to 20micron.
20) The process as claimed in claim 11, wherein the particle filtration efficiency of
said biodegradable filter material is increased by about 28.5% as compared to
cellulose acetate filter.
21) The process as claimed in claim 11, wherein said biodegradable filter material is
degraded to half its dimension material after 24 hours.
22) A process of fabricating an object comprising biodegradable filter material
claimed in claim 1, wherein said process comprising steps of:
a) Pouring said filter material into a moulding object followed by the
treatment in a liquid cryostat at a temperature ranging from -15 to -20°C for
a period ranging from 5 to 10 hours;
b) Freeze drying the moulds resulting from step (a) for a period of about 16
hours.