Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DEGRADABLE CELLULOSE ACETATE TOW BAND COMPRISING A FILLER
PRIORITY CLAIM
[0001] This application claims priority to U.S. Provisional Application No.
63/116,613, filed
on November 20, 2020, the entire contents and disclosures of which are
incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to tow, tow bands, and
cigarette filters
comprising cellulose acetate and a filler. In particular, the present
invention relates to including a
filler in tow, in a tow band, and in a filter, wherein the filler is selected
to increase the
sustainability and biodegradability of the filter.
BACKGROUND OF THE INVENTION
[0003] Cellulose esters are widely used for many purposes, including as
cellulose acetate tow
in cigarette filters. Although cellulose esters such as cellulose acetate are
biopolymers known to
degrade, the rate of degradation is slower than natural cellulose. For
example, cigarette filters
may take up to 15 years to degrade because cellulose acetate does not degrade
until sufficient
acetyl groups have been removed, allowing for microorganisms to recognize the
material for
degradation. After smoking, the filters are often discarded in the environment
and are one of the
most common forms of man-made litter in the world. An estimated 4.5 trillion
cigarette filters
become litter each year. Due to the degradation time of cellulose acetate and
to the plasticizer
contained in the filter, the litter remains longer than desirable. Although
attempts have been
made to form biodegradable filters comprising cellulose acetate, these
attempts have been
unsuccessful for a variety of reasons, including an undesirable change to the
taste of the cigarette
due to modifications and/or additives and degradation time not being
sufficiently reduced.
Molded articles made of cellulose esters suffer from similar deficiencies.
[0004] US Patent No. 5,084,296, incorporated herein by reference, discloses
a composition
comprises a cellulose acetate or other cellulose ester, and an anatase-type
titanium oxide having
(1) a specific surface area of not less than 30 m2 /g, (2) a primary particle
size of 0.001 to 0.07
um, or (3) a specific surface area of not less than 30 m2 /g and a primary
particle size of 0.001 to
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0.07 tm. For improving the photodegradability and the dispersibility, the
surface of the titanium
oxide may be treated with a phosphoric acid salt or other phosphorus compound,
a polyhydric
alcohol, an amino acid or others. Use of a low-substituted cellulose ester
with an average
substitution degree not exceeding 2.15 insures high biodegradability. The
composition may
further contain a plasticizer and/or an aliphatic polyester, a biodegradation
accelerator (e.g.
organic acids or esters thereof). The degradable cellulose ester composition
is highly
photodegradable and moldable and hence useful for the manufacture of various
articles.
[0005] US Patent No. 8,397,733, incorporated herein by reference, discloses
a degradable
cigarette filter which includes a filter element of a bloomed cellulose
acetate tow and a plug wrap
surrounding the filter element, and a pill dispersed in the tow. The pill
includes a material
adapted to catalyze hydrolysis of the cellulose acetate tow that is
encapsulated with an inner
layer of a water soluble or water permeable material and an outer layer of a
cellulose acetate
having a D.S. in the range of 2.0-2.6.
[0006] US Patent Publication No. 2009/0151738, incorporated herein by
reference, discloses
a degradable cigarette filter that includes a filter element of a bloomed
cellulose acetate tow, a
plug wrap surrounding the filter element, and either a coating or a pill in
contact with the tow.
The coating and/or pill may be composed of a material adapted to catalyze
hydrolysis of the
cellulose acetate tow and a water-soluble matrix material. The material may be
an acid, an acid
salt, a base, and/or a bacterium adapted to generate an acid. The coating may
be applied to the
tow, the plug wrap, or both. The pill may be placed in the filter element.
When water contacts the
water-soluble matrix material, the material adapted to catalyze hydrolysis is
released and
catalyzes the hydrolysis, and subsequent degradation, of the cellulose acetate
tow. The foregoing
is also applicable to articles made of cellulose esters.
[0007] Accordingly, there is a need for the controlled and sustained
release of a material that
will aid the degradation of cellulose esters used in cigarette filters.
SUMMARY OF THE INVENTION
[0008] In some aspects, the present disclosure is directed to a cellulose
acetate tow band, the
tow band comprising: a) cellulose acetate having a degree of substitution (DS)
of greater than
1.3; and b) a filler; wherein the filler has a greater rate of degradation
than the cellulose acetate.
In some aspects, the filler may comprise a monosaccharide, polysaccharide,
polysaccharide ester,
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hydrolyzed polysaccharide, oligosaccharide, or combinations thereof. In some
aspects, the filler
may comprises dextran, a hydrolyzed starch, a modified hydrolyzed starch,
hemp, cellulose, or
combinations thereof. The filler may be present from 0.1 to 99.9 % by weight,
based on the total
weight of the tow band, from 0.1 to 75 % by weight, based on the total weight
of the tow band,
from 0.1 to 50 % by weight, based on the total weight of the tow band, or from
0.1 to 25 % by
weight, based on the total weight of the tow band. The degradation rate of the
filler may be at
least 3 % greater than that of the cellulose acetate, at least 10 % greater
than that of the cellulose
acetate, or at least 15 % greater than that of the cellulose acetate. The tow
band may comprise a
weight ratio of the cellulose acetate to the filler from 1:99 to 99:1, from
1:50 to 50:1, or from
1:25 to 25:1. The tow band may comprise cellulose acetate is an amount from
0.1 to 99.9% by
weight, based on the total weight of the tow band. The cellulose acetate may
have a degree of
substitution from 1.3 to 2.9 or from 2 to 2.9. The tow band may comprise from
0.01 to 25 % by
weight additives, based on the total weight of the tow band.
[0009] In some embodiments, the present disclosure is directed to a
cigarette filter
comprising: a filter element comprising bloomed tow, wherein the bloomed tow
comprises a tow
band. The tow band may comprise: a) cellulose acetate having a degree of
substitution (DS) of
greater than 1.3; and b) a filler; wherein the filler has a greater rate of
degradation than the
cellulose acetate. In some aspects, the filler may comprise a monosaccharide,
polysaccharide,
polysaccharide ester, hydrolyzed polysaccharide, oligosaccharide, or
combinations thereof In
some aspects, the filler may comprises dextran, a hydrolyzed starch, a
modified hydrolyzed
starch, hemp, cellulose, or combinations thereof. The filler may be present
from 0.1 to 99.9 % by
weight, based on the total weight of the tow band, from 0.1 to 75 % by weight,
based on the total
weight of the tow band, from 0.1 to 50 % by weight, based on the total weight
of the tow band,
or from 0.1 to 25 % by weight, based on the total weight of the tow band. The
degradation rate of
the filler may be at least 3 % greater than that of the cellulose acetate, at
least 10 % greater than
that of the cellulose acetate, or at least 15 % greater than that of the
cellulose acetate. The tow
band may comprise a weight ratio of the cellulose acetate to the filler from
1:99 to 99:1, from
1:50 to 50:1, or from 1:25 to 25:1. The tow band may comprise cellulose
acetate is an amount
from 0.1 to 99.9 % by weight, based on the total weight of the tow band. The
cellulose acetate
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may have a degree of substitution from 1.3 to 2.9 or from 2 to 2.9. The tow
band may comprise
from 0.01 to 25 % by weight additives, based on the total weight of the tow
band.
[0010] In
some embodiments, the present disclosure is directed to a method for forming a
cigarette filter, the method comprising: a) providing a cellulose acetate tow
band comprising
cellulose acetate and a filler; b) blooming the tow band; and c) forming the
bloomed tow band
into a filter rod. In some aspects, the tow band is formed by: a) combining
cellulose acetate and
the filler with a solvent to form a dope; b) solvent-spinning the dope to form
a plurality of tow
filaments; and c) combining the plurality of tow filaments to form the tow
band. In some aspects,
the tow band is formed by: a) combining cellulose acetate and the filler to
form a flake; b)
combining the flake with a solvent to form a dope; c) solvent-spinning the
dope to form a
plurality of tow filaments; and d) combining the plurality of tow filaments to
form the tow band.
The tow band may comprise: a) cellulose acetate having a degree of
substitution (DS) of greater
than 1.3; and b) a filler; wherein the filler has a greater rate of
degradation than the cellulose
acetate. In some aspects, the filler may comprise a monosaccharide,
polysaccharide,
polysaccharide ester, hydrolyzed polysaccharide, oligosaccharide, or
combinations thereof In
some aspects, the filler may comprises dextran, a hydrolyzed starch, a
modified hydrolyzed
starch, hemp, cellulose, or combinations thereof. The filler may be present
from 0.1 to 99.9 % by
weight, based on the total weight of the tow band, from 0.1 to 75 % by weight,
based on the total
weight of the tow band, from 0.1 to 50 % by weight, based on the total weight
of the tow band,
or from 0.1 to 25 % by weight, based on the total weight of the tow band. The
degradation rate of
the filler may be at least 3 % greater than that of the cellulose acetate, at
least 10 % greater than
that of the cellulose acetate, or at least 15 % greater than that of the
cellulose acetate. The tow
band may comprise a weight ratio of the cellulose acetate to the filler from
1:99 to 99:1, from
1:50 to 50:1, or from 1:25 to 25:1. The tow band may comprise cellulose
acetate is an amount
from 0.1 to 99.9 % by weight, based on the total weight of the tow band. The
cellulose acetate
may have a degree of substitution from 1.3 to 2.9 or from 2 to 2.9. The tow
band may comprise
from 0.01 to 25 % by weight additives, based on the total weight of the tow
band.
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DETAILED DESCRIPTION OF THE INVENTION
Introduction
[0011] The present disclosure is directed to forming tow, tow bands, and
cigarette filters
using the comprising the combination of a cellulose ester (e.g., cellulose
acetate) and a filler. The
cellulose ester may have a degree of substitution of greater than 1.3 and the
filler may be selected
to have a greater rate of degradation than the cellulose ester. In some
aspects, the filler may be a
monosaccharide, polysaccharide, or combinations thereof In further aspects,
the filler may
comprise dextran, a hydrolyzed starch, a modified hydrolyzed starch,
cellulose, or combinations
thereof. The filler may be present from 0.1 to 99.9 % by weight of the tow,
depending on the
desired degradation, filler, and mechanism for degradation. In some aspects,
the filler is present
from 0.1 to 75 % by weight of the tow, e.g., from 0.1 to 50 % by weight, from
0.1 to 20 % by
weight, and all values in between. The degradation rate of the filler may be
at least 3 % greater
than that of the cellulose acetate, e.g., at least 5 % greater, at least 7 %
greater, at least 10 %
greater, at least 15 % greater, or at least 20 % greater.
[0012] The present disclosure is also directed to methods of forming the
tow, tow bands, and
cigarette filters. In some aspects, the filler may be combined with the
cellulose ester (e.g.,
cellulose acetate) to form a dope, which is then solvent-spun to form the tow.
Depending on the
filler, the filler may be added after the dope is formed, such as during fiber
formation. Once the
fibers are formed (tow), the fibers are combined to form a tow band. The tow
band may then be
subjected to additional treatments, packaged, and eventually formed into
filter rods for use in
cigarette filters.
[0013] The basic mechanism of cellulose ester degradation is dependent on
the degree of
substitution ("DS") of the cellulose ester. DS of cellulose ester refers to
the degree of substitution
and may be measured, for example for cellulose acetate, by ASTM 871-96 (2010).
When the
cellulose acetate has a DS of greater than 1.3, cellulose acetate is not
degraded by naturally
occurring enzymes or bacteria due to the acetate moieties present. To replace
the acetate moieties
with hydroxyl moieties, and thereby reduce the DS, the cellulose acetate is
hydrolyzed.
Hydrolysis of the acetyl moieties is also referred to as deacetylation. The
degradable cigarette
filters described herein typically have a DS of greater than 1.3, often in the
range of 2.0 to 2.6,
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but up to as high as 2.9 and accordingly, are not degraded by naturally
occurring enzymes or
bacteria due to the acetate moieties present.
[0014] Without being bound by theory, it is believed that by incorporating
a filler having a
greater degradation rate than that of the cellulose ester, the degradation of
the tow, tow band, and
cigarette filter may be accelerated. The selection of the filler is made to
balance the
improvements in degradation with the filtration performance. For example, the
filler may be
selected to have a small enough domain to avoid being filtered out. Some
fillers, such as starch,
glucose, or dextran, as described further herein, may serve as a food source
for a variety of
microbials. Such fillers would allow for the microbial growth to be
established directly on the
tow, tow band, or cigarette filter, leading to accelerated degradation.
Combinations of different
fillers may be used to take advantage of different properties and performance
of the filers. For
example, dextran may be included to improve degradation while hemp or short
continuous fibers
may be included to improve other mechanical properties.
Cellulose Ester
[0015] As described herein, the present disclosure relates to tow, tow
bands, and cigarette
filters including a filler, along with a cellulose ester, e.g., cellulose
acetate. The filler is included
with the cellulose ester, preferably prior to tow formation, in order to
enhance the degradation
rate of the cellulose ester. Cellulose acetate, as used herein, refers to
cellulose diacetate, though
the filler and methods described herein may be used for other types of
cellulose esters, including
cellulose triacetate, cellulose propionate, cellulose acetate-propionate,
cellulose butyrate,
cellulose acetate-butyrate, cellulose propionate-butyrate, cellulose nitrate,
cellulose sulfate,
cellulose phthalate and combinations thereof
[0016] Cellulose esters may be prepared by known processes, including those
disclosed in
U.S. Patent No. 2,740,775 and in U.S. Publication No. 2013/0096297, the
entireties of which are
incorporated herein by reference. Typically, acetylated cellulose is prepared
by reacting cellulose
with an acetylating agent in the presence of a suitable acidic catalyst and
then de-esterifying.
[0017] The cellulose may be sourced from a variety of materials, including
cotton linters, a
softwood or from a hardwood. Softwood is a generic term typically used in
reference to wood
from conifers (i.e., needle-bearing trees from the order Pinales). Softwood-
producing trees
include pine, spruce, cedar, fir, larch, douglas-fir, hemlock, cypress,
redwood and yew.
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Conversely, the term hardwood is typically used in reference to wood from
broad-leaved or
angiosperm trees. The terms "softwood" and "hardwood" do not necessarily
describe the actual
hardness of the wood. While, on average, hardwood is of higher density and
hardness than
softwood, there is considerable variation in actual wood hardness in both
groups, and some
softwood trees can actually produce wood that is harder than wood from
hardwood trees. One
feature separating hardwoods from softwoods is the presence of pores, or
vessels, in hardwood
trees, which are absent in softwood trees. On a microscopic level, softwood
contains two types of
cells, longitudinal wood fibers (or tracheids) and transverse ray cells. In
softwood, water
transport within the tree is via the tracheids rather than the pores of
hardwoods. In some aspects,
a hardwood cellulose is preferred for acetylating.
[0018] Acylating agents can include both carboxylic acid anhydrides (or
simply anhydrides)
and carboxylic acid halides, particularly carboxylic acid chlorides (or simply
acid chlorides).
Suitable acid chlorides can include, for example, acetyl chloride, propionyl
chloride, butyryl
chloride, benzoyl chloride and like acid chlorides. Suitable anhydrides can
include, for example,
acetic anhydride, propionic anhydride, butyric anhydride, benzoic anhydride
and like anhydrides.
Mixtures of these anhydrides or other acylating agents can also be used in
order to introduce
differing acyl groups to the cellulose. Mixed anhydrides such as, for example,
acetic propionic
anhydride, acetic butyric anhydride and the like can also be used for this
purpose in some
embodiments.
[0019] In most cases, the cellulose is exhaustively acetylated with the
acetylating agent to
produce a derivatized cellulose having a high degree of substitution (DS)
value, such as from 2.4
to 3, along with some additional hydroxyl group substitution (e.g., sulfate
esters) in some cases.
Exhaustively acetylating the cellulose refers to an acetylation reaction that
is driven toward
completion such that as many hydroxyl groups as possible in cellulose undergo
an acetylation
reaction.
[0020] Suitable acidic catalysts for promoting the acetylation of cellulose
often contain
sulfuric acid or a mixture of sulfuric acid and at least one other acid. Other
acidic catalysts not
containing sulfuric acid can similarly be used to promote the acetylation
reaction. In the case of
sulfuric acid, at least some of the hydroxyl groups in the cellulose can
become initially
functionalized as sulfate esters during the acetylation reaction. Once
exhaustively acetylated, the
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cellulose is then subjected to a controlled partial de-esterification step,
generally in the presence
of a de-esterification agent, also referred to as a controlled partial
hydrolysis step.
[0021] De-esterification, as used herein, refers to a chemical reaction
during which one or
more of the ester groups of the intermediate cellulosic ester are cleaved from
the cellulose
acetate and replaced with a hydroxyl group, resulting in a cellulose acetate
product having a
(second) DS of less than 3. "De-esterifying agent," as used herein, refers to
a chemical agent
capable of reacting with one or more of the ester groups of the cellulose
acetate to form hydroxyl
groups on the intermediate cellulosic ester. Suitable de-esterifying agents
include low molecular
weight alcohols, such as methanol, ethanol, isopropyl alcohol, pentanol, R-OH,
wherein R is Cl
to C20 alkyl group, and mixtures thereof. Water and a mixture of water and
methanol may also
be used as the de-esterifying agent. Typically, most of these sulfate esters
are cleaved during the
controlled partial hydrolysis used to reduce the amount of acetyl
substitution. The reduced
degree of substitution may range from 0.5 to 3.0, e.g., from 1.3 to 3, from
1.3 to 2.9, from 1.5 to
2.9 or from 2 to 2.6. For purposes of this disclosure, the degree of
substitution is typically from
1.3 to 2.9 since below 1.3, natural degradation may occur. The degree of
substitution may be
selected based on the at least one organic solvent to be used in the binder
composition. For
example, when acetone is used as the organic solvent, the degree of
substitution may range from
2.2 to 2.65. As used herein, "degradation" may refer to any degradation
mechanism and rate,
including photo chemical degradation, biodegradation, or any form of
degradation. When
comparing degradation of cellulose acetate to the filler, the comparison may
be based on the
same degradation mechanism so as to compare like rates.
[0022] The number average molecular weight of the cellulose ester may range
from 30,000
amu to 100,000 amu, e.g., from 50,000 amu to 80,000 amu and may have a
polydispersity from
1.5 to 2.5, e.g., from 1.75 to 2.25 or from 1.8 to 2.2. All molecular weight
recited herein, unless
otherwise specified, are number average molecular weights. The molecular
weight may be
selected based on the desired hardness of the final tow or filter rod.
Although greater molecular
weight leads to increased hardness, greater molecular weight also increases
viscosity. The
cellulose ester may be provided in powder or flake form.
[0023] In some aspects, blends of different molecular weight cellulose
ester flake or powder
may be used. Accordingly, a blend of high molecular weight cellulose ester,
e.g., a cellulose
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ester having a molecular weight above 60,000 amu, may be blended with a low
molecular weight
cellulose ester, e.g., a cellulose ester having a molecular weight below
60,000 amu. The ratio of
high molecular weight cellulose ester to low molecular weight cellulose ester
may vary but may
generally range from 1:10 to 10:1; e.g., from 1:5 to 5:1 or from 1:3 to 3:1.
Blends of different
cellulose esters may also be used and may include two, three, four, or more
different cellulose
esters in varied ratios. In some aspects, one cellulose ester may be present
in a majority while
other cellulose esters are present in smaller amounts.
Cellulose Ester Fibers, Tow, and Tow Bales
[0024] There are a number of methods of forming fibers from cellulose
esters (e.g., cellulose
acetate) which may be employed to form the tow of the present disclosure. In
some
embodiments, to form fibers from cellulose ester, a dope is formed by
dissolving the cellulose
ester flake or powder in a solvent to form a dope solution. The dope solution
is typically a highly
viscous solution. The solvent of the dope solution may be selected from the
group consisting of
water, acetone, methylethyl ketone, methylene chloride, dioxane, dimethyl
formamide, methanol,
ethanol, glacial acetic acid, supercritical carbon dioxide, any suitable
solvent capable of
dissolving the aforementioned polymers, and combinations thereof. In some
aspects, the solvent
is acetone or a combination of acetone and up to 5 wt.% water. The dope is
then filtered and
deaerated prior to being spun to form fibers, referred to as solvent-spinning.
The dope may be
spun in a spinner comprising one or more cabinets, each cabinet comprising a
spinneret. The
spinneret comprises holes that affect the rate at which the solvent evaporates
from the fibers.
[0025] The filler described herein may be added to the dope and is limited
by having a
degradation rate that is greater than that of the cellulose ester. The
degradation rate of the
cellulose ester is dependent on the degree of substitution as well as the
environment that the
cellulose ester is exposed to for degradation. Exemplary fillers include
monosaccharides (e.g.,
glucose, sucrose, lactose, fructose, galactose, ribose, xylose, etc.),
polysaccharides (e.g.,
polysaccharide ester, hydrolyzed polysaccharide, oligosaccharide, starches,
cellulose, including
alpha-cellulose, hemicellulose, hyaluronic, alginate, guar gums, chitin, and
chondroitin, modified
starches, hydrolyzed starches, hemp seed polysaccharide, etc.) As described
herein, the filler
may be selected so that it may be included in the dope, i.e., has a small
enough domain that it
will not be filtered out. This size may be dependent on the size of the
spinneret holes. Exemplary
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fillers to be included in the dope include monosaccharides, polysaccharides,
polysaccharide
ester, hydrolyzed polysaccharide, oligosaccharide, or combinations thereof.
[0026] The solvent may be included in the dope in an amount from 60 to 90 %
by weight,
e.g., from 60 to 85 % by weight, from 60 to 80 % by weight, from 60 to 75 % by
weight, from 60
to 70 % by weight, from 60 to 65 % by weight, from 65 to 90 % by weight, from
70 to 90 % by
weight, from 75 to 90 % by weight, from 80 to 90% by weight, or from 85 to 90
% by weight.
All values in between are also contemplated and included.
[0027] The filler may be included in the dope in an amount sufficient to
achieve the desired
improvement in degradation rate of the tow, tow band, or cigarette filter
while balancing the
desired properties of the tow, tow band, or cigarette filter. For example, the
filler may be present
from 0.1 to 39% by weight of the dope, e.g., from 0.1 to 35 % by weight, from
0.1 to 30% by
weight, from 0.1 to 25 % by weight, from 0.1 to 20 % by weight by weight, from
0.1 to 15 % by
weight, from 0.1 to 10 % by weight, from 0.1 to 7.5 % by weight, or from 0.1
to 5 % by weight.
In further aspects, the lower limit of the filler may be at least 0.5 % by
weight, at least 0.75 % by
weight, at least 1 % by weight, at least 2 % by weight, or at least 3 % by
weight. All other values
and ranges in between the above cited values are also included and
contemplated.
[0028] The cellulose acetate may be included in the dope in an amount
sufficient to retain the
desired properties of the tow, tow band, or cigarette filter, e.g., filtration
of the cigarette filter.
For example, the cellulose acetate may be present from 0.1 to 39.9 % by weight
of the dope, e.g.,
from 0.1 to 37.5 % by weight, from 0.1 to 35 % by weight, from 0.1 to 30% by
weight, from 0.1
to 25 % by weight by weight, from 0.1 to 20 % by weight, from 0.1 to 15 % by
weight, from 0.1
to 10% by weight, from 0.1 to 7.5 % by weight, or from 0.1 to 5 % by weight.
In further aspects,
the lower limit of the cellulose acetate may be at least 0.5 % by weight, at
least 0.75 % by
weight, at least 1 % by weight, at least 2 % by weight, at least 3 % by
weight, at least 5 % by
weight, at least 10 % by weight, at least 15 % by weight, at least 20 % by
weight, at least 25 %
by weight, at least 30 % by weight, at least 35 % by weight, at least 37.5 %,
at least 39 %, or at
least 39.5 %. All other values and ranges in between the above cited values
are also included and
contemplated.
[0029] Pigments may also be added to the dope. The dope may comprise, for
example, from
to 40 wt.% cellulose acetate, from 0.1 to 35 % filler, and from 60 to 90 wt.%
solvent.
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Pigments, when added, may be present from 0.1 to 5 wt.%, e.g., from 0.1 to 4
wt.%, from 0.1 to
3 wt.% from 0.1 to 2 wt.%, from 0.5 to 5 wt.%, from 0.5 to 4 wt.%, from 0.5 to
3 wt.%, from 0.5
to 2 wt.%, from 1 to 5 wt.%, from 1 to 4 wt.%, from 1 to 3 wt.% or from 1 to 2
wt.%. The
pigment added to the dope is not particularly limited, and any conventional
pigment may be
used. Examples of common, suitable pigments include calcium carbonate,
diatomaceous earth,
magnesium oxide, zinc oxide, and barium sulfate.
[0030] Generally, the production of a bale of tow bands may involve
spinning fibers from the
dope, forming a tow containing the fibers, forming a tow band from the fibers,
crimping the tow
band, and baling the crimped tow band. Within said production, optional steps
may include, but
are not limited to, warming the fibers after spinning, applying a finish or
additive to the fibers
and/or tow band prior to crimping, and conditioning the crimped tow band. The
parameters of at
least these steps are important for producing desirable bales.
[0031] In some aspects, if the filler has too large of a domain to be
included in the dope, the
filler may be included at a later point in the process, such as any of the
steps described above.
Specifically, the filler may be added to the cellulose acetate flake.
[0032] It should be noted that bales may vary in size and shape as needed
for further
processing. In some embodiments, bales may have dimensions ranging from 30
inches (76 cm)
to 60 inches (152 cm) in height, 46 inches (117 cm) to 56 inches (142 cm) in
length, and 35
inches (89 cm) to 45 inches (114 cm) in width. In some embodiments, bales may
range in weight
from 900 pounds (408 kg) to 2100 pounds (953 kg). In some embodiments, bales
may have a
density greater than 300 kg/m3 (18.8 lb/ft3).
Fibers
[0033] The structure of the cellulose acetate fibers for use in the present
disclosure is not
particularly limited, and various known fiber structures may be employed. For
example, the tow
band may utilize fibers having a broad range of denier per filament (dpf). In
some embodiments,
the tow band has from 1 to 30 dpf, e.g., from 2 to 28 dpf, from 3 to 25 dpf,
from 4 to 22 dpf,
from 5 to 30 dpf, from 5 to 28 dpf, from 5 to 25 dpf, from 5 to 22 dpf, from
10 to 30 dpf, from 10
to 28 dpf, from 10 to 25 dpf, from 10 to 22 dpf, from 15 to 30 dpf, from 15 to
28 dpf, from 15 to
25 dpf, from 15 to 22 dpf, from 20 to 30 dpf, from 20 to 28 dpf, from 20 to 25
dpf, or from 20 to
22 dpf.
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[0034] The fibers for use in the present disclosure may have any suitable
cross-sectional
shape, including, but not limited to, circular, substantially circular,
crenulated, ovular,
substantially ovular, polygonal, substantially polygonal, dog-bone, "Y," "X,"
"K," "C," multi-
lobe, and any hybrid thereof. As used herein, the term "multi-lobe" refers to
a cross-sectional
shape having a point (not necessarily in the center of the cross-section) from
which at least two
lobes extend (not necessarily evenly spaced or evenly sized).
[0035] As noted above, fibers for use in the present disclosure may be
produced by any
method known to one skilled in the art. As noted, in some embodiments, fibers
may be produced
by spinning a dope through a spinneret. As used herein, the term "dope" refers
to a cellulose
acetate solution and/or suspension from which fibers are produced. In some
embodiments, a
dope may comprise cellulose acetate, filler, and solvents. In some
embodiments, a dope for use
in conjunction with the present disclosure may comprise cellulose acetate,
filler, solvents, and
additives. In some embodiments, the cellulose acetate may be at a
concentration in the dope
ranging from 10 to 40 wt. percent (e.g., from 20 to 30 wt.%, from 25 to 40
wt.%, from 25 to 30
wt.%), and the solvent may be at a concentration from 60 to 90 wt.% (e.g., 60
to 80 wt.%, 70 to
80 wt.%, 80 to 90 wt.%). The filler and additives may make up the remainder of
the dope. In
some embodiments, the dope may be heated to a temperature ranging from 40 C
to 100 C (e.g.,
from 45 C to 95 C, from 50 C to 90 C, from 55 C to 85 C, from 60 C to
80 C).
[0036] Suitable solvents may include, but not be limited to, water,
acetone, methylethyl
ketone, methylene chloride, dioxane, dimethyl formamide, methanol, ethanol,
glacial acetic acid,
supercritical CO2, any suitable solvent capable of dissolving the
aforementioned polymers, or
any combination thereof. By way of nonlimiting example, a solvent for
cellulose acetate may be
an acetone/methanol mixture. In some embodiments, to produce very high dpf
values of the
present disclosure, increased solvent levels compared with amounts for typical
dpf values (e.g., 2
to 8 dpf) may be used. For example in some embodiments, to produce very high
dpf tow, solvent
amounts may be from 5 to 30 wt. % greater when compared with solvent amounts
for typical dpf
tow. Additional solvent amounts may, in some cases, present challenges to the
processing of the
fibers.
[0037] Some embodiments of the present disclosure may involve treating
fibers to achieve
surface functionality on the fibers. In some embodiments, fibers may comprise
a surface
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functionality including, but not limited to, biodegradability sites (e.g.,
defect sites to increase
surface area to enhance biodegradability), chemical handles (e.g., carboxylic
acid groups for
subsequent functionalization), active particle binding sites (e.g., sulfide
sites binding gold
particles or chelating groups for binding iron oxide particles), sulfur
moieties, or any
combination thereof One skilled in the art should understand the plurality of
methods and
mechanisms to achieve surface functionalities. Some embodiments may involve
dipping,
spraying, ionizing, functionalizing, acidizing, hydrolyzing, exposing to a
plasma, exposing to an
ionized gas, or any combination thereof to achieve surface functionalities.
Suitable chemicals to
impart a surface functionality may be any chemical or collection of chemicals
capable of reacting
with cellulose acetate including, but not limited to, acids (e.g., sulfuric
acid, nitric acid, acetic
acid, hydrofluoric acid, hydrochloric acid, and the like), reducing agents
(e.g., LiA1H4, NaBH4,
H2/Pt, and the like), Grignard reagents (e.g., CH3MgBr, and the like), trans-
esterification
reagent, amines (e.g., R¨NH3 like CH3NH3), or any combination thereof Exposure
to plasmas
and/or ionized gases may react with the surface, produce defects in the
surface, or any
combination thereof Said defects may increase the surface area of the fibers
which may yield
higher loading and/or higher filtration efficacy in the final filter products.
[0038] Some embodiments of the present disclosure may involve applying a
finish to the
fibers. Suitable finishes may include, but not be limited to, at least one of
the following: oils
(e.g., mineral oils or liquid petroleum derivatives), water, additives, or any
combination thereof.
Examples of suitable mineral oils may include, but not be limited to, water
white (i.e., clear)
mineral oil having a viscosity of 80-95 SUS (Sabolt Universal Seconds)
measured at 38 C (100
F.). Examples of suitable emulsifiers may include, but not be limited to,
sorbitan monolaurate,
e.g., SPAN 20 (available from Croda, Wilmington, Del.), poly(ethylene oxide)
sorbitan
monolaurate, e.g., TWEEN 20 (available from Croda, Wilmington, Del.). The
water may be
de-mineralized water, de-ionized water, or otherwise appropriately filtered
and treated water.
The lubricant or finish may be applied by spraying or wiping. Generally, the
lubricant or finish is
added to the fiber prior to forming the fibers into tow.
[0039] In some embodiments of the present disclosure, finish may be applied
as a neat finish
or as a finish emulsion in water. As used herein, the term "neat finish"
refers to a finish
formulation without the addition of excess water. It should be noted that
finish formulations may
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comprise water. In some embodiments, finish may be applied neat followed by
applying water
separately.
[0040] In some embodiments of the present disclosure, a finished emulsion
may comprise
less than 98% water, less than 95%, less than 92%, or less than 85%. In some
embodiments, it
may be advantageous in later steps to have fibers having a lower weight
percentage of moisture
(e.g., 5% to 25% w/w of the tow band), of which water is a contributor. The
water content of the
finished emulsion may be at least one parameter that may assist in achieving
said weight
percentage of moisture in the fibers. Therefore, in some embodiments, a
finished emulsion may
comprise less than 92% water, less than 85% water, or less than 75% water.
Tow
[0041] Once the dope is formed and solvent-spun, the solvent is evaporated
and the dope is
spun and extruded to form a plurality of extruded fibers, referred to as tow.
[0042] The filler may be included in the tow in an amount sufficient to
achieve the desired
improvement in degradation rate of the tow, tow band, or cigarette filter
while balancing the
desired properties of the tow, tow band, or cigarette filter. For example, the
filler may be present
from 0.1 to 99 % by weight of the tow, e.g., from 0.1 to 95 % by weight, from
0.1 to 90 % by
weight, from 0.1 to 85 % by weight, from 0.1 to 80 % by weight by weight, from
0.1 to 75 % by
weight, from 0.1 to 70 % by weight, from 0.1 to 65 % by weight, from 0.1 to 60
% by weight,
from 0.1 to 55 % by weight, from 0.1 to 50% by weight, from 0.1 to 45 % by
weight, from 0.1
to 40% by weight, from 0.1 to 35 % by weight, from 0.1 to 30% by weight, from
0.1 to 25 % by
weight, from 0.1 to 20% by weight, from 0.1 to 15 % by weight, from 0.1 to 10%
by weight, or
from 0.1 to 5 % by weight. In further aspects, the lower limit of the filler
may be at least 0.5 %
by weight, at least 0.75 % by weight, at least 1 % by weight, at least 2 % by
weight, or at least 3
% by weight. All other values and ranges in between the above cited values are
also included and
contemplated.
[0043] The cellulose acetate may be included in the tow in an amount
sufficient to retain the
desired properties of the tow, tow band, or cigarette filter, e.g., filtration
of the cigarette filter.
For example, the cellulose acetate may be present from 0.1 to 99 % by weight
of the tow, e.g.,
from 0.1 to 95 % by weight, from 0.1 to 90 % by weight, from 0.1 to 85 % by
weight, from 0.1
to 80 % by weight by weight, from 0.1 to 75 % by weight, from 0.1 to 70 % by
weight, from 0.1
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to 65 % by weight, from 0.1 to 60% by weight, from 0.1 to 55 % by weight, from
0.1 to 50% by
weight, from 0.1 to 45 % by weight, from 0.1 to 40% by weight, from 0.1 to 35
% by weight,
from 0.1 to 30% by weight, from 0.1 to 25 % by weight, from 0.1 to 20% by
weight, from 0.1
to 15 % by weight, from 0.1 to 10% by weight, or from 0.1 to 5 % by weight. In
further aspects,
the lower limit of the cellulose acetate may be at least 0.5 % by weight, at
least 0.75 % by
weight, at least 1 % by weight, at least 2 % by weight, at least 3 % by
weight, at least 5 % by
weight, at least 10 % by weight, at least 15 % by weight, at least 20 % by
weight, at least 25 %
by weight, at least 30 % by weight, at least 35 % by weight, at least 40 % by
weight, at least 45
% by weight, at least 50 % by weight, or greater. All other values and ranges
in between the
above cited values are also included and contemplated. Furthermore, the above
included ranges
for the tow also apply to the tow band and filter rod incorporated into a
cigarette filter.
[0044] The weight ratio of the cellulose acetate to the filler in the dope,
tow, tow band, filter
rod, and cigarette filter may also vary, including from 1:99 to 99:1, e.g.,
from 1:75 to 75:1, from
1:50 to 50:1, from 1:25 to 25:1, from 1:10 to 10:1, from 1:5 to 5:1, from 1:3
to 3:1, from 1:2 to
2:1, or approximately 1:1. In some embodiments, the cellulose acetate is
present in a greater
weight ratio than the filler, e.g., at least 1.5:1, at least 2:1, at least
3:1, at least 5:1, at least 10:1,
at least 15:1, at least 20:1, at least 25:5, or at least 50:1, including all
ranges in between.
[0045] The tow, tow band, filter rod, and cigarette filter may also
comprise additives. The
additives may be present in an amount from 0.01 to 25 % by weight, e.g., from
0.01 to 20 % by
weight, from 0.1 to 20% by weight, from 0.1 to 15 % by weight, from 0.1 to 10%
by weight, or
from 0.1 to 5 % by weight. In further aspects, the lower limit of the
cellulose acetate may be at
least 0.5 % by weight, at least 0.75 % by weight, at least 1 % by weight, at
least 2 % by weight,
at least 3 % by weight, at least 5 % by weight, at least 10 % by weight, at
least 15 % by weight,
at least 20 % by weight, at least 25 % by weight, at least 30 % by weight, at
least 35 % by
weight, at least 40 % by weight, at least 45 % by weight, at least 50 % by
weight, or greater. All
other values and ranges in between the above cited values are also included
and contemplated.
[0046] Once the tow is formed, it may be combined to form a tow band which
comprises a
plurality of tow filaments. In some embodiments, the tow band is from 10,000
to 100,000 total
denier, e.g., from 15,000 to 100,000, from 20,000 to 100,000, from 25,000 to
100,000, from
30,000 to 100,000, from 10,000 to 90,000, from 15,000 to 90,000, from 20,000
to 90,000, from
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25,000 to 90,000, from 30,000 to 90,000, from 10,000 to 90,000, from 15,000 to
90,000, from
20,000 to 90,000, from 25,000 to 90,000, from 30,000 to 90,000, from 10,000 to
80,000, from
15,000 to 80,000, from 20,000 to 80,000, from 25,000 to 80,000, from 30,000 to
80,000, from
10,000 to 70,000, from 15,000 to 70,000, from 20,000 to 70,000, from 25,000 to
70,000, from
30,000 to 70,000, from 10,000 to 60,000, from 15,000 to 60,000, from 20,000 to
60,000, from
25,000 to 60,000, or from 30,000 to 60,000. In terms of upper limits, the tow
band may be less
than 100,000 total denier, e.g., less than 90,000, less than 80,000, less than
70,000, or less than
60,000. In terms of lower limits, the tow band may be greater than 10,000
total denier, e.g.,
greater than 15,000, greater than 20,000, greater than 25,000, or greater than
30,000.
[0047] In some embodiments, the tow can have a breaking strength between
3.5 kg and 25
kg, e.g. from 3.5 kg to 22.5 kg, from 3.5 kg to 20 kg, from 3.5 kg to 17.5 kg,
from 3.5 kg to 15
kg, from 4 kg to 25 kg, from 4 kg to 22.5 kg, from 4 kg to 20 kg, from 4 kg to
17.5 kg, from 4 kg
to 15 kg, from 4.5 kg to 25 kg, from 4.5 kg to 22.5 kg, from 4.5 kg to 20 kg,
from 4.5 kg to 17.5
kg, from 4.5 kg to 15 kg, from 5 kg to 25 kg, from 5 kg to 22.5 kg, from 5 kg
to 20 kg, from 5 kg
to 17.5 kg, or from 5 kg to 15 kg. In terms of upper limits, the tow may have
a breaking strength
of less than 25 kg, e.g., less than 22.5 kg, less than 20 kg, less than 17.5
kg, or less than 15 kg. In
terms of lower limits, the tow may have a breaking strength of greater than
3.5 kg, e.g. greater
than 4 kg, greater than 4.5 kg, or greater than 5 kg.
[0048] In some embodiments of the present disclosure, a tow band may
comprise more than
one type of fiber. In some embodiments, the more than one type of fiber may
vary based on dpf,
cross-sectional shape, composition, treatment prior to forming the tow band,
or any combination
thereof. Examples of suitable additional fibers may include, but are not
limited to, carbon fibers,
activated carbon fibers, natural fibers, synthetic fibers, or any combination
thereof Further
examples include some cellulose acetate tow that includes filler and some
cellulose acetate tow
that does not include filler. The weight ratio of tow including filler to tow
excluding filler may
range from 1:99 to 99:1, e.g., from 1:75 to 75:1, from 1:50 to 50:1, from 1:25
to 25:1, from 1:10
to 10:1, from 1:5 to 5:1, from 1:3 to 3:1, from 1:2 to 2:1, or approximately
1:1. In some
embodiments, the cellulose acetate is present in a greater weight ratio than
the filler, e.g., at least
1.5:1, at least 2:1, at least 3:1, at least 5:1, at least 10:1, at least 15:1,
at least 20:1, at least 25:5,
or at least 50:1, including all ranges in between. It is also contemplated
that different types of
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filler may be included in different tow, which is ultimately combined to form
a tow band. For
example, some tow filaments may include a monosaccharide while other tow
filaments may
include a different filler, such as a polysaccharide or a starch.
Additionally, the tow may include
filler that is integral to the tow, e.g., added to the flake, powder, or dope,
and filler that is added
at a later part of the manufacturing process, such as a cellulose or certain
starches.
[0049] Some embodiments of the present disclosure may include crimping the
tow band to
form a crimped tow band. Crimping the tow band may involve using any suitable
crimping
technique known to those skilled in the art. These techniques may include a
variety of
apparatuses including, but not limited to, a stuffer box or a gear.
Nonlimiting examples of
crimping apparatuses and the mechanisms by which they work can be found in
U.S. Pat. Nos.
7,610,852 and 7,585,441, the entire contents and disclosures of which are
incorporated herein by
reference. Suitable stuffer box crimpers may have smooth crimper nip rolls,
threaded or grooved
crimper nip rolls, textured crimper nip rolls, upper flaps, lower flaps, or
any combination thereof.
[0050] The configuration of the crimp may play a role in the processability
of the final bale.
Examples of crimp configurations may include, but not be limited to, lateral,
vertical, some
degree between lateral and vertical, random, or any combination thereof As
used herein, the
term "lateral" when describing crimp orientation refers to crimp or fiber
bends in the plane of the
tow band. As used herein, the term "vertical" when describing a crimp
orientation refers to crimp
projecting outside of the plane of the tow band and perpendicular to the plane
of the tow band. It
should be noted that the terms lateral and vertical refer to general overall
crimp orientation and
may have deviation from said configuration by +/¨ 30 degrees.
[0051] In some embodiments of the present disclosure, a crimped tow band
may comprise
fibers with a first crimp configuration and fibers with a second crimp
configuration.
[0052] In some embodiments of the present disclosure, a crimped tow band
may comprise
fibers with at least a vertical crimp configuration near the edges and fibers
with at least a lateral
crimp configuration near the center. In some embodiments, a crimped tow band
may comprise
fibers with a vertical crimp configuration near the edges and fibers with a
lateral crimp
configuration near the center.
[0053] The configuration of the crimp may be important for the
processability of the final
bale in subsequent processing steps, e.g., a lateral crimp configuration may
provide better
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cohesion of fibers than a vertical crimp configuration unless further steps
are taken to enhance
cohesion. Methods for crimping tow bands with a substantially later crimp
configuration are
disclosed, for example, in U.S. Pub. No. 2013/0115452 and U.S. Pub. No.
2015/0128964, each
of which is incorporated herein in its entirety.
[0054] In some embodiments of the present disclosure, the fibers may be
adhered to each
other to provide better processability of the final bale. While adhesion
additives may be used in
conjunction with any crimp configuration, it may be advantageous to use
adhesion additives with
a vertical crimp configuration. In some embodiments, adhering may involve
adhesion additives
on and/or in the fibers. Examples of such adhesion additives may include, but
not be limited to,
binders, adhesives, resins, tackifiers, or any combination thereof It should
be noted that any
additive described herein, or otherwise, capable of adhering two fibers
together may be used,
which may include, but not be limited to, active particles, active compounds,
ionic resins,
zeolites, nanoparticles, ceramic particles, softening agents, plasticizers,
pigments, dyes,
flavorants, aromas, controlled release vesicles, surface modification agents,
lubricating agents,
emulsifiers, vitamins, peroxides, biocides, antifungals, antimicrobials,
antistatic agents, flame
retardants, antifoaming agents, degradation agents, conductivity modifying
agents, stabilizing
agents, or any combination thereof. Some embodiments of the present disclosure
may involve
adding adhesive additives to the fibers (in, on, or both) by incorporating the
adhesive additives
into the dope, incorporating the adhesive additives into the finish, applying
the adhesive
additives to the fibers (before, after, and/or during forming the tow band),
applying the adhesive
additives to the tow band (before, after, and/or during crimping), or any
combination thereof.
[0055] Adhesive additives may be included in and/or on the fibers at a
concentration
sufficient to adhere the fibers together at a plurality of contact points to
provide better
processability of the final bale. The concentration of adhesive additives to
use may depend on the
type of adhesive additive and the strength of adhesion the adhesive additive
provides. In some
embodiments, the concentration of adhesive additive may range from a lower
limit of 0.01%,
0.05%, 0.1%, or 0.25% to an upper limit of 5%, 2.5%, 1%, or 0.5% by weight of
the tow band in
the final bale. It should be noted that for additives that are used for more
than adhesion, the
concentration in the tow band in the final bale may be higher, e.g., 25% or
less.
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[0056] Further, some embodiments of the present disclosure may involve
heating the fibers
before, after, and/or during crimping. While said heating may be used in
conjunction with any
crimp configuration, it may be advantageous to use said heating with a
vertical crimp
configuration. Said heating may involve exposing the fibers of the tow band to
steam,
aerosolized compounds (e.g., plasticizers), liquids, heated fluids, direct
heat sources, indirect
heat sources, irradiation sources that causes additives in the fibers (e.g.,
nanoparticles) to
produce heat, or any combination thereof.
[0057] Some embodiments of the present disclosure may include conditioning
the crimped
tow band. Conditioning may be used to achieve a crimped tow band having a
residual acetone
content of 0.5% or less w/w of the crimped tow band. Conditioning may be used
to achieve a
crimped tow band having a residual water content of 8% or less w/w of the
crimped tow band.
Conditioning may involve exposing the fibers of the crimped tow band to steam,
aerosolized
compounds (e.g., plasticizers), liquids, heated fluids, direct heat sources,
indirect heat sources,
irradiation sources that causes additives in the fibers (e.g., nanoparticles)
to produce heat, or any
combination thereof
[0058] UCE is the amount of work required to uncrimp a fiber. UCE, as
reported hereinafter,
is sampled prior to baling, i.e., post-drying and pre-baling. UCE, as used
herein, is measured as
follows: using a warmed up (20 minutes before conventional calibration)
Instron tensile tester
(Model 1130, crosshead gears¨Gear gs R1940-1 and R940-2, Instron Series IX-
Version 6 data
acquisition & analysis software, Instron 50 Kg maximum capacity load cell,
Instron top roller
assembly, 1" x4"x1/4" thick high grade Buna-N 70 Shore A durometer rubber grip
faces), a
preconditioned tow sample (preconditioned for 24 hours at 22 C 2 C and
Relative humidity at
60% 2%) of about 76 cm in length is looped over and spread evenly across the
center of the top
roller, pre-tensioned by gently pulling to 100 g 2 g (per readout display),
and each end of the
sample is clamped (at the highest available pressure, but not exceeding the
manufacturers
recommendations) in the lower grips to effect a 50 cm gauge length (gauge
length measured
from top of the robber grips), and then tested, until break, at a crosshead
speed of 30 cm/minute.
This test is repeated until three acceptable tests are obtained and the
average of the three data
points from these tests is reported. Energy (E) limits are between 0.220 kg
and 10.0 kg.
Displacement (D) has a preset point of 10.0 kg. UCE is calculated by the
formula: UCE
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(gcm/cm)=(E*1000)/((D*2)+500). Breaking strength can be calculated using the
same test and
the following equation BS = L (where L is the load at max load (kg)). In
certain embodiments of
the disclosure, UCE values (in gcm/cm) can range from 190 to 400, e.g., 200 to
300, e.g., 290. In
certain embodiments of the disclosure breaking strength can range from between
3.5 kg and 25
kg, e.g. 4 kg to 20 kg, 4.5 kg to 15 kg, or 5 kg to 12 kg.
Cigarette Filter
[0059] A degradable cigarette filter generally includes a filter element
(or filter plug) made
of a bloomed cellulose acetate tow comprising the filler and a plug wrap
surrounding the filter
element. Cellulose acetate tow may be delivered to a filter producer as a
bale. The tow is then
opened or "bloomed" in rodmaking equipment in order to form the filter rod and
eventual
cigarette filter. Various properties are desirable for a cigarette filter,
including firmness, pressure
drop, pressure drop variability, openability, fly, and uncramping energy. The
filler described
herein, as well as the amount used, may be chosen to balance these properties
with degradability
of the cigarette filter.
Embodiments
[0060] Embodiment 1: A cellulose acetate tow band, the tow band comprising:
a) cellulose
acetate having a degree of substitution (DS) of greater than 1.3; and b) a
filler; wherein the filler
has a greater rate of degradation than the cellulose acetate.
[0061] Embodiment 2: The tow band according to Embodiment 1, wherein the
filler
comprises a monosaccharide, polysaccharide, polysaccharide ester, hydrolyzed
polysaccharide,
oligosaccharide, or combinations thereof
[0062] Embodiment 3: The tow band according to Embodiment 1 or 2, wherein
the filler
comprises dextran, a hydrolyzed starch, a modified hydrolyzed starch, hemp,
cellulose, or
combinations thereof.
[0063] Embodiment 4: The tow band according to any of Embodiments 1-3,
wherein the
filler is present from 0.1 to 99.9 % by weight, based on the total weight of
the tow band.
[0064] Embodiment 5: The tow band according to any of Embodiments 1-4,
wherein the
filler is present from 0.1 to 75 % by weight, based on the total weight of the
tow band.
[0065] Embodiment 6: The tow band according to any of Embodiments 1-5,
wherein the
filler is present from 0.1 to 50 % by weight, based on the total weight of the
tow band.
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[0066] Embodiment 7: The tow band according to any of Embodiments 1-6,
wherein the
filler is present from 0.1 to 25 % by weight, based on the total weight of the
tow band.
[0067] Embodiment 8: The tow band according to any of Embodiments 1-7,
wherein the
degradation rate of the filler is at least 3 % greater than that of the
cellulose acetate.
[0068] Embodiment 9: The tow band according to any of Embodiments 1-8,
wherein the
degradation rate of the filler is at least 10 % greater than that of the
cellulose acetate.
[0069] Embodiment 10: The tow band according to any of Embodiments 1-9,
wherein the
degradation rate of the filler is at least 15 % greater than that of the
cellulose acetate.
[0070] Embodiment 11: The tow band according to any of Embodiments 1-10,
wherein the
tow band comprises a weight ratio of the cellulose acetate to the filler from
1:99 to 99:1.
[0071] Embodiment 12: The tow band according to any of Embodiments 1-11,
wherein the
tow band comprises a weight ratio of the cellulose acetate to the filler from
1:50 to 50:1.
[0072] Embodiment 13: The tow band according to any of Embodiments 1-12,
wherein the
tow band comprises a weight ratio of the cellulose acetate to the filler from
1:25 to 25:1.
[0073] Embodiment 14: The tow band according to any of Embodiments 1-13,
wherein the
tow band comprises cellulose acetate is an amount from 0.1 to 99.9 % by
weight, based on the
total weight of the tow band.
[0074] Embodiment 15: The tow band according to any of Embodiments 1-14,
wherein the
cellulose acetate has a degree of substitution from 2 to 2.9.
[0075] Embodiment 16: The tow band according to any of Embodiments 1-15,
wherein the
tow band comprises from 0.01 to 25 % by weight additives, based on the total
weight of the tow
band.
[0076] Embodiment 17: A cigarette filter comprising: a filter element
comprising bloomed
tow, wherein the bloomed tow comprises the tow band according to any of
Embodiments 1-16.
[0077] Embodiment 18: A method for forming the cigarette filter of
Embodiment 17, the
method comprising a)
providing the cellulose acetate tow band; b) blooming the tow
band; and c) forming the bloomed tow band into a filter rod.
[0078] Embodiment 19: The method of Embodiment 18, wherein the tow band is
formed by:
a) combining cellulose acetate and the filler with a solvent to form a dope;
b) solvent-spinning
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WO 2022/109253 PCT/US2021/060066
the dope to form a plurality of tow filaments; and c) combining the plurality
of tow filaments to
form the tow band.
[0079] Embodiment 20: The method of Embodiment 18, wherein the tow band is
formed by:
a) combining cellulose acetate and the filler to form a flake; b) combining
the flake with a
solvent to form a dope; c) solvent-spinning the dope to form a plurality of
tow filaments; and d)
combining the plurality of tow filaments to form the tow band.
[0080] While the invention has been described in detail, modifications
within the spirit and
scope of the invention will be readily apparent to those of skill in the art.
It should be understood
that aspects of the invention and portions of various embodiments and various
features recited
above and/or in the appended claims may be combined or interchanged either in
whole or in part.
In the foregoing descriptions of the various embodiments, those embodiments
which refer to
another embodiment may be appropriately combined with other embodiments as
will be
appreciated by one of ordinary skill in the art. Furthermore, those of
ordinary skill in the art will
appreciate that the foregoing description is by way of example only, and is
not intended to limit
the invention.
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