JP7802775B2 - Degradable cellulose acetate tow bands containing fillers - Google Patents

Description

CLAIM OF PRIORITY This application claims priority to U.S. Provisional Patent Application No. 63/116,613, filed November 20, 2020, the entire contents and disclosure of which are incorporated herein by reference.

The present invention generally relates to tow, tow bands, and cigarette filters comprising cellulose acetate and a filler. Specifically, the present invention relates to fillers contained in the tow, tow bands, and filters, which are selected to enhance the durability and biodegradability of the filters.

Cellulose esters are widely used for many purposes, including as cellulose acetate tow in cigarette filters. Cellulose esters, such as cellulose acetate, are biopolymers known to degrade, but at a slower rate than natural cellulose. For example, cigarette filters can take up to 15 years to decompose because cellulose acetate does not decompose until enough acetyl groups are removed to allow microorganisms to recognize the material for degradation. After smoking, filters are often discarded in the environment and are one of the most common forms of human-caused waste worldwide. An estimated 4.5 trillion cigarette filters are littered each year. Due to the degradation time of cellulose acetate and the plasticizers contained in the filters, litter remains longer than desired. Attempts have been made to create biodegradable filters containing cellulose acetate, but these attempts have been unsuccessful for a variety of reasons, including undesirable changes in cigarette taste due to modifications and/or additives, and insufficient degradation times. Molded articles composed of cellulose esters suffer from similar deficiencies.

U.S. Patent No. 5,084,296, incorporated herein by reference, discloses a composition comprising cellulose acetate or other cellulose ester and anatase titanium dioxide having (1) a specific surface area of 30 m2/g or greater, (2) a primary particle size of 0.001 to 0.07 μm, or (3) a specific surface area of 30 m2/g or greater and a primary particle size of 0.001 to 0.07 μm. To improve photodegradability and dispersibility, the surface of the titanium dioxide can be treated with phosphate or other phosphorus compounds, polyhydric alcohols, amino acids, etc. The use of low-substituted cellulose esters with an average degree of substitution not exceeding 2.15 ensures high biodegradability. The composition may further contain a plasticizer and/or an aliphatic polyester, and a biodegradation promoter (e.g., an organic acid or its ester). Degradable cellulose ester compositions are highly photodegradable and moldable, making them useful for the production of various articles.

U.S. Patent No. 8,397,733, incorporated herein by reference, discloses a degradable cigarette filter comprising a bloomed cellulose acetate tow filter element, a plug wrap surrounding the filter element, and pills dispersed in the tow. The pills comprise a material configured to catalyze the hydrolysis of the cellulose acetate tow encapsulated by an inner layer of a water-soluble or water-permeable material and an outer layer of cellulose acetate having a degree of substitution (D.S.) in the range of 2.0 to 2.6.

U.S. Patent Application Publication No. 2009/0151738, incorporated herein by reference, discloses a degradable cigarette filter comprising a filter element of opened cellulose acetate tow, plug wrap surrounding the filter element, and either a coating or pills in contact with the tow. The coating and/or pills can be composed of a material configured to catalyze the hydrolysis of the cellulose acetate tow and water-soluble matrix material. This material can be an acid, an acid salt, a base, and/or a bacterium configured to produce an acid. The coating can be applied to the tow, the plug wrap, or both. The pills can be encased in the filter element. When water contacts the water-soluble matrix material, the material configured to catalyze the hydrolysis is released, catalyzing the hydrolysis and subsequent degradation of the cellulose acetate tow. The above is also applicable to articles composed of cellulose esters.

Therefore, there is a need for controlled and sustained release of materials that aid in the degradation of cellulose esters used in cigarette filters.

In some embodiments, the present disclosure is directed to a cellulose acetate tow band, the tow band comprising: a) cellulose acetate having a degree of substitution (DS) greater than 1.3; and b) a filler, wherein the filler has a greater degradation rate than cellulose acetate. In some embodiments, the filler may include a monosaccharide, a polysaccharide, a polysaccharide ester, a hydrolyzed polysaccharide, an oligosaccharide, or a combination thereof. In some embodiments, the filler may include dextran, hydrolyzed starch, modified hydrolyzed starch, hemp, cellulose, or a combination thereof. The filler may be present in an amount of 0.1 to 99.9 wt.% based on the total weight of the tow band, 0.1 to 75 wt.% based on the total weight of the tow band, 0.1 to 50 wt.% based on the total weight of the tow band, or 0.1 to 25 wt.% based on the total weight of the tow band. The filler's degradation rate may be at least 3% greater than that of cellulose acetate, at least 10% greater than that of cellulose acetate, or at least 15% greater than that of cellulose acetate. The tow band may contain a weight ratio of cellulose acetate to filler of 1:99 to 99:1, 1:50 to 50:1, or 1:25 to 25:1. The tow band may contain cellulose acetate in an amount of 0.1 to 99.9 wt.% based on the total weight of the tow band. The cellulose acetate may have a degree of substitution of 1.3 to 2.9, or 2 to 2.9. The tow band may contain 0.01 to 25 weight percent of the additive, based on the total weight of the tow band.

In some embodiments, the present disclosure is directed to a cigarette filter including a filter element comprising opened tow, wherein the opened tow includes a tow band. The tow band may include: a) cellulose acetate having a degree of substitution (DS) greater than 1.3; and b) a filler; wherein the filler has a greater degradation rate than cellulose acetate. In some embodiments, the filler may include a monosaccharide, a polysaccharide, a polysaccharide ester, a hydrolyzed polysaccharide, an oligosaccharide, or a combination thereof. In some embodiments, the filler may include dextran, hydrolyzed starch, modified and hydrolyzed starch, hemp, cellulose, or a combination thereof. The filler may be present in an amount of 0.1 to 99.9 wt.% based on the total weight of the tow band, 0.1 to 75 wt.% based on the total weight of the tow band, 0.1 to 50 wt.% based on the total weight of the tow band, or 0.1 to 25 wt.% based on the total weight of the tow band. The filler's degradation rate may be at least 3% greater than that of cellulose acetate, at least 10% greater than that of cellulose acetate, or at least 15% greater than that of cellulose acetate. The tow band may contain a weight ratio of cellulose acetate to filler of 1:99 to 99:1, 1:50 to 50:1, or 1:25 to 25:1. The tow band may contain cellulose acetate in an amount of 0.1 to 99.9 wt.% based on the total weight of the tow band. The cellulose acetate may have a degree of substitution of 1.3 to 2.9, or 2 to 2.9. The tow band may contain 0.01 to 25 weight percent of the additive, based on the total weight of the tow band.

In some embodiments, the present disclosure is directed to a method for forming a cigarette filter, the method including the steps of: a) providing a cellulose acetate tow band including cellulose acetate and a filler; b) opening the tow band; and c) forming the opened tow band into a filter rod. In some aspects, the tow band is formed by the steps of: a) combining the 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) bundling the plurality of tow filaments to form the tow band. In some aspects, the tow band is formed by the steps of: a) combining the cellulose acetate and the filler with a solvent to form flakes; b) combining the flakes with a solvent to form a dope; c) solvent-spinning the dope to form a plurality of tow filaments; and d) bundling the plurality of tow filaments to form the tow band. The tow band may comprise: a) cellulose acetate having a degree of substitution (DS) greater than 1.3; and b) a filler, wherein the filler has a greater degradation rate than cellulose acetate. In some embodiments, the filler may comprise a monosaccharide, a polysaccharide, a polysaccharide ester, a hydrolyzed polysaccharide, an oligosaccharide, or a combination thereof. In some embodiments, the filler may comprise dextran, hydrolyzed starch, modified hydrolyzed starch, hemp, cellulose, or a combination thereof. The filler may be present in an amount of 0.1 to 99.9 wt.% based on the total weight of the tow band, 0.1 to 75 wt.% based on the total weight of the tow band, 0.1 to 50 wt.% based on the total weight of the tow band, or 0.1 to 25 wt.% based on the total weight of the tow band. The filler may have a degradation rate at least 3% greater than that of cellulose acetate, at least 10% greater than that of cellulose acetate, or at least 15% greater than that of cellulose acetate. The tow band may contain a weight ratio of cellulose acetate to filler of 1:99 to 99:1, 1:50 to 50:1, or 1:25 to 25:1. The tow band may contain cellulose acetate in an amount of 0.1 to 99.9 wt. % based on the total weight of the tow band. The cellulose acetate may have a degree of substitution of 1.3 to 2.9, or 2 to 2.9. The tow band may contain 0.01 to 25 wt. % of additives based on the total weight of the tow band.

Introduction The present disclosure is directed to forming tow, tow bands, and cigarette filters using a combination of a cellulose ester (e.g., cellulose acetate) and a filler. The cellulose ester may have a degree of substitution greater than 1.3, and the filler may be selected to have a greater degradation rate than the cellulose ester. In some embodiments, the filler may be a monosaccharide, a polysaccharide, or a combination thereof. In further embodiments, the filler may include dextran, hydrolyzed starch, modified hydrolyzed starch, cellulose, or a combination thereof. The filler may be present in an amount of 0.1 to 99.9% by weight of the tow, depending on the desired degradation, filler, and mechanism for degradation. In some embodiments, the filler is present in an amount of 0.1 to 75% by weight of the tow, e.g., 0.1 to 50% by weight, 0.1 to 20% by weight, including all values in between. The degradation rate of the filler may be at least 3% greater than that of cellulose acetate, such as at least 5% greater, at least 7% greater, at least 10% greater, at least 15% greater, or at least 20% greater.

The present disclosure is also directed to methods for forming tows, tow bands, and cigarette filters. In some embodiments, the filler may be combined with a cellulose ester (e.g., cellulose acetate) to form a dope, which is then solvent-spun to form a tow. Depending on the filler, the filler may be added after the dope is formed, for example, while the fibers are being formed. Once the fibers are formed (the tow), the fibers are bundled to form a tow band. The tow band may then undergo additional processing, packaging, and ultimately be formed into a filter rod for use in a cigarette filter.

The basic mechanism of cellulose ester degradation depends on the degree of substitution ("DS") of the cellulose ester. The DS of a cellulose ester refers to its degree of substitution; for example, for cellulose acetate, it can be measured according to ASTM 871-96 (2010). If the cellulose acetate has a DS greater than 1.3, the cellulose acetate will not be degraded by naturally occurring enzymes or bacteria due to the presence of acetate moieties. Replacing the acetate moieties with hydroxyl moieties reduces the DS, causing the cellulose acetate to undergo hydrolysis. Hydrolysis of the acetyl moieties is also known as deacetylation. The degradable cigarette filters described herein typically have a DS greater than 1.3, often in the range of 2.0 to 2.6, but at most 2.9, and therefore will not be degraded by naturally occurring enzymes or bacteria due to the presence of acetate moieties.

Without being bound by theory, it is believed that the incorporation of a filler with a degradation rate greater than that of the cellulose ester can accelerate the degradation of the tow, tow band, and cigarette filter. The filler can be selected to balance improved degradation with filtration performance. For example, the filler can be selected to form small enough domains to prevent filter out. Some fillers, such as starch, glucose, or dextran, can serve as a food source for various microorganisms. Such fillers would allow the microorganisms to grow and colonize directly on the tow, tow band, or cigarette filter, accelerating degradation. The use of various fillers in combination can take advantage of their various properties and performance capabilities. For example, the addition of dextran improves degradation, while the addition of hemp or continuous short fiber improves other mechanical properties.

As described herein, the present disclosure relates to tow, tow bands, and cigarette filters that contain a filler together with a cellulose ester, such as cellulose acetate. The filler is preferably included with the cellulose ester prior to the formation of the tow in order to increase the decomposition rate of the cellulose ester. As used herein, cellulose acetate refers to cellulose diacetate, but the fillers and methods described herein can be used with 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.

Cellulose esters can be prepared by known processes, including those disclosed in U.S. Pat. No. 2,740,775 and U.S. Patent Application Publication No. 2013/0096297, both of which are incorporated herein by reference in their entireties. Typically, acetylated cellulose is prepared by reacting cellulose with an acetylating agent in the presence of a suitable acidic catalyst, followed by deesterification.

Cellulose can be sourced from a variety of materials, including cotton linters, softwoods, or hardwoods. Softwood is a generic term typically used to refer to wood from conifers (i.e., needle-bearing trees from the Pinaceae family). Trees that produce softwood include pine, spruce, cedar, fir, larch, Douglas-fir, hemlock, cypress, sequoia, and yew. Conversely, the term hardwood is typically used to refer to wood from broadleaf or angiosperm trees. The terms "softwood" and "hardwood" do not necessarily describe the wood's actual hardness. While hardwoods, on average, are denser and harder than softwoods, there is considerable variation in the actual wood hardness of both groups, and some softwood trees can actually produce wood that is harder than wood from hardwood trees. One characteristic that distinguishes hardwood from softwood is the presence of pores or tubes in hardwood trees, which are absent in softwood trees. At the microscopic level, softwoods contain two types of cells: longitudinal wood fibers (or tracheids) and transverse rays. In softwoods, water transport within the wood occurs through the tracheids, unlike the pores in hardwoods. In some embodiments, hardwood cellulose is preferred for acetylation.

Acylating agents include carboxylic acid anhydrides (or simply anhydrides) and carboxylic acid halides, particularly carboxylic acid chlorides (or simply acid chlorides). Suitable acid chlorides include, for example, acetyl chloride, propionyl chloride, butyryl chloride, benzoyl chloride, and similar acid chlorides. Suitable anhydrides include, for example, acetic anhydride, propionic anhydride, butyric anhydride, benzoic anhydride, and similar anhydrides. Mixtures of these anhydrides or other acylating agents can also be used to introduce various acyl groups into cellulose. For example, mixed anhydrides such as acetic propionic anhydride and acetic butyric anhydride can also be used for this purpose in some embodiments.

In most cases, cellulose is exhaustively acetylated with an acetylating agent to produce derivatized cellulose with a high degree of substitution (DS) of 2.4 to 3, optionally with some additional hydroxyl group substitution (e.g., sulfate esters). Exhaustively acetylating cellulose means that the acetylation reaction is driven to completion so that as many hydroxyl groups in the cellulose as possible undergo the acetylation reaction.

Suitable acid catalysts for promoting the acetylation of cellulose often contain sulfuric acid or a mixture of sulfuric acid and at least one other acid. Other acid catalysts that do not contain sulfuric acid can also be used to promote the acetylation reaction. In the case of sulfuric acid, at least some of the hydroxyl groups in the cellulose can be first functionalized as sulfate esters during the acetylation reaction. Once thoroughly acetylated, the cellulose then undergoes a controlled partial deesterification step, generally in the presence of a deesterifying agent. This is called a controlled partial hydrolysis step.

Deesterification, as used herein, refers to a chemical reaction in which one or more of the ester groups of an intermediate cellulose ester are sequestered from the cellulose acetate and replaced with a hydroxyl group, resulting in a cellulose acetate product having a (second) DS of less than 3. As used herein, "deesterifying agent" refers to a chemical agent capable of reacting with one or more of the ester groups of the cellulose acetate to form hydroxyl groups in the intermediate cellulose ester. Suitable deesterifying agents include low molecular weight alcohols, such as methanol, ethanol, isopropyl alcohol, pentanol, R—OH (where R is a C1-C20 alkyl group), and mixtures thereof. Water and mixtures of water and methanol can also be used as deesterifying agents. Typically, most of these sulfate esters are separated during the controlled partial hydrolysis used to reduce the amount of acetyl substitution. The degree of substitution reduced can range from 0.5 to 3.0, e.g., 1.3 to 3, 1.3 to 2.9, 1.5 to 2.9, or 2 to 2.6. For purposes of this disclosure, the degree of substitution is typically 1.3 to 2.9, as natural degradation can occur below 1.3. The degree of substitution can be selected based on the at least one organic solvent used in the binder composition. For example, if acetone is used as the organic solvent, the degree of substitution can range from 2.2 to 2.65. As used herein, the term "degradation" refers to various degradation mechanisms and rates, including photochemical degradation, biodegradation, or various forms of degradation. When comparing the degradation of cellulose acetate to a filler, the rates can be compared similarly, since the comparison is based on the same degradation mechanism.

The number average molecular weight of the cellulose ester can range from 30,000 amu to 100,000 amu, e.g., from 50,000 amu to 80,000 amu, and can have a polydispersity of 1.5 to 2.5, e.g., from 1.75 to 2.25 or from 1.8 to 2.2. Unless otherwise specified, all molecular weights stated herein are number average molecular weights. The molecular weight can be selected based on the desired hardness of the final tow or filter rod. Higher molecular weights lead to increased hardness, but higher molecular weights also increase viscosity. The cellulose ester can be provided in powder or flake form.

In some embodiments, mixtures of cellulose ester flakes or powders of different molecular weights may be used. Thus, a blend of high molecular weight cellulose esters, e.g., cellulose esters having a molecular weight greater than 60,000 amu, may be blended with low molecular weight cellulose esters, e.g., cellulose esters having a molecular weight less than 60,000 amu. The ratio of high molecular weight cellulose ester to low molecular weight cellulose ester may vary, but generally ranges from 1:10 to 10:1, e.g., 1:5 to 5:1 or 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 various ratios. In some embodiments, one cellulose ester may be present in a majority amount, while other cellulose esters are present in smaller amounts.

Cellulose Ester Fibers, Tows, and Tow Bales There are several methods for forming fibers from cellulose esters (e.g., cellulose acetate) that can be utilized to form the tows of the present disclosure. In some embodiments, to form fibers from cellulose esters, a dope is formed by dissolving cellulose ester flakes or powder in a solvent to form a dope solution. The dope solution is typically a highly viscous solution. The solvent for the dope solution can be selected from the group consisting of water, acetone, methyl ethyl ketone, methylene chloride, dioxane, dimethylformamide, methanol, ethanol, glacial acetic acid, supercritical carbon dioxide, any suitable solvent capable of dissolving the polymer, and combinations thereof. In some embodiments, the solvent is acetone or a combination of acetone and up to 5% water by weight. The dope is then filtered, degassed, and then spun to form fibers (referred to as solvent-spinning). The dope can be spun in a spinner containing one or more cabinets, each cabinet containing a spinneret. The spinneret is equipped with holes that affect the rate at which the solvent evaporates from the fibers.

The fillers described herein can be added to the dope, with the limitation that they have a degradation rate greater than that of the cellulose ester. The degradation rate of the cellulose ester depends on the degree of substitution and the environment to which the cellulose ester is exposed to degradation. Examples of fillers include monosaccharides (e.g., glucose, sucrose, lactose, fructose, galactose, ribose, xylose, etc.), polysaccharides (e.g., polysaccharide esters, hydrolyzed polysaccharides, oligosaccharides, starch, alpha-cellulose, cellulose including hemicellulose, hyaluronic acid, alginate, guar gum, chitin, and chondroitin, modified starch, hydrolyzed starch, hemp seed polysaccharides, etc.). As described herein, the fillers are selected so that they can be contained within the dope, i.e., as small enough domains to prevent filtration. This size may depend on the size of the spinneret holes. Examples of fillers present in the dope include monosaccharides, polysaccharides, polysaccharide esters, hydrolyzed polysaccharides, oligosaccharides, or combinations thereof.

The solvent can be included in the dope in an amount of 60-90% by weight, e.g., 60-85% by weight, 60-80% by weight, 60-75% by weight, 60-70% by weight, 60-65% by weight, 65-90% by weight, 70-90% by weight, 75-90% by weight, 80-90% by weight, or 85-90% by weight. All values in between are contemplated and included therein.

The filler can be included in the dope in an amount sufficient to achieve the desired improvement in the decomposition 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 can be present in an amount of 0.1 to 39% by weight of the dope, e.g., 0.1 to 35% by weight, 0.1 to 30% by weight, 0.1 to 25% by weight, 0.1 to 20% by weight, 0.1 to 15% by weight, 0.1 to 10% by weight, 0.1 to 7.5% by weight, or 0.1 to 5% by weight. In further embodiments, the lower limit of the filler is 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 between the above-cited values are also included and contemplated.

Cellulose acetate may be included in the dope in an amount sufficient to maintain the desired properties of the tow, tow band, or cigarette filter, such as the filterability of the cigarette filter. For example, the cellulose acetate may be present in an amount of 0.1 to 39.9% by weight of the dope, e.g., 0.1 to 37.5% by weight, 0.1 to 35% by weight, 0.1 to 30% by weight, 0.1 to 25% by weight, 0.1 to 20% by weight, 0.1 to 15% by weight, 0.1 to 10% by weight, 0.1 to 7.5% by weight, or 0.1 to 5% by weight. In further embodiments, the lower limit of cellulose acetate may be at least 0.5 wt%, at least 0.75 wt%, at least 1 wt%, at least 2 wt%, at least 3 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 37.5%, at least 39%, or at least 39.5%. All other values and ranges between the above-cited values are also included and contemplated.

A pigment may be added to the dope. The dope may contain, for example, 5 to 40% by weight of cellulose acetate, 0.1 to 35% by weight of a filler, and 60 to 90% by weight of a solvent. When added, the pigment may be present at 0.1 to 5% by weight, e.g., 0.1 to 4% by weight, 0.1 to 3% by weight, 0.1 to 2% by weight, 0.5 to 5% by weight, 0.5 to 4% by weight, 0.5 to 3% by weight, 0.5 to 2% by weight, 1 to 5% by weight, 1 to 4% by weight, 1 to 3% by weight, or 1 to 2% by weight. 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.

Generally, the production of a tow band bale can include spinning fibers from a 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 this production, optional steps can include, but are not limited to, warming the fibers after spinning, finishing or applying additives to the fibers and/or tow band before crimping, and conditioning the crimped tow band. The parameters of at least these steps are important to producing the desired bale.

In some embodiments, if the filler has too many domains in the dope, the filler is included later in the process, such as in one of the steps previously mentioned. Specifically, the filler may be added to the cellulose acetate flakes.

It should be noted that bales can vary in size and shape as needed for further processing. In some embodiments, bales can 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 can weigh from 900 pounds (408 kg) to 2100 pounds (953 kg). In some embodiments, bales can have a density greater than 300 kg/m³ (18.8 lb/ft³).

The structure of the cellulose acetate fiber used in the present disclosure is not particularly limited, and various known fiber structures can be utilized. For example, the tow band can utilize fibers having a wide range of denier per filament (dpf). In some embodiments, the tow band can have a denier per filament (dpf) of 1 to 30, e.g., 2 to 28, 3 to 25, 4 to 22, 5 to 30, 5 to 28, 5 to 25, 5 to 22, 10 to 30, 10 to 28, 10 to 25, 10 to 22, 15 to 30, 15 to 28, 15 to 25, 15 to 22, 20 to 30, 20 to 28, 20 to 25, or 20 to 22.

Fibers used in the present disclosure may have any suitable cross-sectional shape, including, but not limited to, circular, substantially circular, sawtooth, elliptical, substantially elliptical, polygonal, substantially polygonal, dogbone, "Y", "X", "K", "C", multi-lobal, and any combination thereof. As used herein, the term "multi-lobal" means a cross-sectional shape having a point (including, but not limited to, at the center of the cross-sectional view) from which at least two lobes (including, but not limited to, uniformly spaced or uniformly sized) extend.

As noted above, the fibers used in the present disclosure may be produced by any method known to those skilled in the art. As indicated, in some embodiments, fibers may be produced by spinning a dope through a spinneret. As used herein, the term "dope" refers to the cellulose acetate solution and/or suspension from which fibers are produced. In some embodiments, the dope may include cellulose acetate, a filler, and a solvent. In some embodiments, a dope for use in connection with the present disclosure may include cellulose acetate, a filler, a solvent, and an additive. In some embodiments, the cellulose acetate may be present in a concentration in the dope ranging from 10 to 40% by weight (e.g., 20 to 30% by weight, 25 to 40% by weight, 25 to 30% by weight), and the solvent may be present in a concentration of 60 to 90% by weight (e.g., 60 to 80% by weight, 70 to 80% by weight, 80 to 90% by weight). Fillers and additives may make up the remainder of the dope. In some embodiments, the dope can be heated to a temperature in the range of 40°C to 100°C (e.g., 45°C to 95°C, 50°C to 90°C, 55°C to 85°C, 60°C to 80°C).

Suitable solvents include, but are not limited to, water, acetone, methyl ethyl ketone, methylene chloride, dioxane, dimethylformamide, methanol, ethanol, glacial acetic acid, supercritical CO2, and any suitable solvent or combination thereof capable of dissolving the polymer. As a non-limiting example, a solvent for cellulose acetate can be an acetone/methanol mixture. In some embodiments, to produce the very high dpf values of the present disclosure, increased solvent levels can be used compared to amounts for typical dpf values (e.g., 2-8 dpf). For example, in some embodiments, to produce very high dpf tows, the amount of solvent can be 5-30% by weight greater when compared to the amount of solvent for a typical dpf tow. The additional solvent amount can, in some cases, pose challenges to fiber processing.

Some embodiments of the present disclosure may include treating the fibers to achieve surface functionality on the fibers. In some embodiments, the fibers may include surface functionality including, but not limited to, biodegradable sites (e.g., defect sites that increase surface area to enhance biodegradability), chemical handles (e.g., carboxylic acid groups for subsequent functionalization), active particle binding sites (e.g., sulfide sites for binding gold particles or chelating groups for binding iron oxide particles), sulfur moieties, or any combination thereof. Those skilled in the art should appreciate multiple methods and mechanisms for achieving surface functionality. Some embodiments may include immersion, spraying, ionization, functionalization, acidification, hydrolysis, exposure to plasma, exposure to ionized gas, or any combination thereof to achieve surface functionality. Suitable chemicals for imparting surface functionality can 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, etc.), reducing agents (e.g., LiAlH4, NaBH4, H2/Pt, etc.), Grignard reagents (e.g., CH3MgBr, etc.), transesterification agents, amines (e.g., R-NH3 such as CH3NH3), or any combination thereof. Exposure to plasma and/or ionized gases can react with the surface, create surface defects, or any combination thereof. The defects can increase the surface area of the fiber, resulting in higher loadings and/or higher filtration effectiveness in the final filter product.

Some embodiments of the present disclosure may require the application of a finish to the fibers. Suitable finishes may include, but are not limited to, at least one of oil (e.g., mineral oil or liquid petroleum derivatives), water, additives, or any combination thereof. Examples of suitable mineral oils may include, but are not limited to, water-white (i.e., clear) mineral oils having a viscosity of 80 to 95 SUS (Sabolt Universal Seconds) measured at 38°C (100°F). Examples of suitable emulsifiers may include, but are not limited to, sorbitan monolaurate, such as SPAN® 20 (available from Croda, Wilmington, Del.), poly(ethylene oxide) sorbitan monolaurate, such as TWEEN® 20 (available from Croda, Wilmington, Del.). Water may be demineralized water, deionized water, or water that has been otherwise appropriately filtered and treated. The lubricant or finish may be applied by spraying or wiping. Generally, the lubricant or finish is added to the fibers before they are formed into a tow.

In some embodiments of the present disclosure, the finish may be applied as a neat finish or as a finishing emulsion in water. As used herein, the term "neat finish" refers to a finishing formulation that does not include the addition of excessive amounts of water. Note that the finishing formulation may include water. In some embodiments, the finish may be applied neat, followed by a separate application of water.

In some embodiments of the present disclosure, the finished emulsion may contain less than 98%, less than 95%, less than 92%, or less than 85% water. In some embodiments, having fibers with a lower weight percentage moisture (e.g., 5% to 25% w/w of the tow band) where water is a factor may be advantageous in later steps. The moisture content of the finished emulsion may be at least one parameter that can assist in achieving the weight percentage of moisture in the fibers. Thus, in some embodiments, the finished emulsion may contain less than 92% water, less than 85% water, or less than 75% water.

Once the tow dope is formed and solvent-spun, the solvent is evaporated and the dope is spun and extruded to form a plurality of extruded fibers (called a tow).

The filler can be included in the tow in an amount sufficient to achieve the desired improvement in the decomposition rate of the tow, tow band, or cigarette filter, while balancing the desired properties in the tow, tow band, or cigarette filter. For example, the filler may be present in an amount of 0.1 to 99 wt% of the tow, e.g., 0.1 to 95 wt%, 0.1 to 90 wt%, 0.1 to 85 wt%, 0.1 to 80 wt%, 0.1 to 75 wt%, 0.1 to 70 wt%, 0.1 to 65 wt%, 0.1 to 60 wt%, 0.1 to 55 wt%, 0.1 to 50 wt%, 0.1 to 45 wt%, 0.1 to 40 wt%, 0.1 to 35 wt%, 0.1 to 30 wt%, 0.1 to 25 wt%, 0.1 to 20 wt%, 0.1 to 15 wt%, 0.1 to 10 wt%, or 0.1 to 5 wt%. In further embodiments, the filler lower limit is at least 0.5 wt%, at least 0.75 wt%, at least 1 wt%, at least 2 wt%, or at least 3 wt%. All other values and ranges between the above-quoted values are also included and contemplated.

Cellulose acetate may be present in the tow in an amount sufficient to maintain desired properties of the tow, tow band, or cigarette filter, such as the filterability of the cigarette filter. For example, the cellulose acetate may be present in an amount of 0.1 to 99% by weight of the tow, e.g., 0.1 to 95% by weight, 0.1 to 90% by weight, 0.1 to 85% by weight, 0.1 to 80% by weight, 0.1 to 75% by weight, 0.1 to 70% by weight, 0.1 to 65% by weight, 0.1 to 60% by weight, 0.1 to 55% by weight, 0.1 to 50% by weight, 0.1 to 45% by weight, 0.1 to 40% by weight, 0.1 to 35% by weight, 0.1 to 30% by weight, 0.1 to 25% by weight, 0.1 to 20% by weight, 0.1 to 15% by weight, 0.1 to 10% by weight, or 0.1 to 5% by weight. In further embodiments, the lower limit of cellulose acetate may be at least 0.5 wt%, at least 0.75 wt%, at least 1 wt%, at least 2 wt%, at least 3 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, or at least 50 wt%, or more. All other values and ranges between the above-cited values are also included and contemplated. Furthermore, the ranges for tow set forth above also apply to the tow band and filter rod incorporated into the cigarette filter.

The weight ratio of cellulose acetate to filler in the dope, tow, tow band, filter rod, and cigarette filter can vary, for example, 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 weight ratio greater than the filler, for example, 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).

The tow, tow band, filter rod, and cigarette filter may further include additives. These additives may be present in an amount of 0.01 to 25% by weight, e.g., 0.01 to 20% by weight, 0.1 to 20% by weight, 0.1 to 15% by weight, 0.1 to 10% by weight, or 0.1 to 5% by weight. In further embodiments, 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, or at least 50% by weight, or more. All other values and ranges between the above-cited values are also included and contemplated.

Once the tow is formed, it is bundled to form a tow band, which includes multiple tow filaments. In some embodiments, the tow band has a total denier of 10,000 to 100,000, e.g., 15,000 to 100,000, 20,000 to 100,000, 25,000 to 100,000, 30,000 to 100,000, 10,000 to 90,000, 15,000 to 90,000, 20,000 to 90,000, 25,000 to 90,000, 30,000 to 90,000, 10,000 to 90,000, 15,000 to 90,000, 20,000 to 90,000, 25,000 to 90,000 0, 30,000 to 90,000, 10,000 to 80,000, 15,000 to 80,000, 20,000 to 80,000, 25,000 to 80,000, 30,000 to 80,000, 10,000 to 70,000, 15,000 to 70,000, 20,000 to 70,000, 25,000 to 70,000, 30,000 to 70,000, 10,000 to 60,000, 15,000 to 60,000, 20,000 to 60,000, 25,000 to 60,000 or 30,000 to 60,000. On the upper limit, the tow band can be less than 100,000 total denier, for example, less than 90,000, less than 80,000, less than 70,000, or less than 60,000. On the lower limit, the tow band can be greater than 10,000 total denier, for example, greater than 15,000, greater than 20,000, greater than 25,000, or greater than 30,000.

In some embodiments, the tow can have a breaking strength of 3.5 kg to 25 kg, e.g., 3.5 kg to 22.5 kg, 3.5 kg to 20 kg, 3.5 kg to 17.5 kg, 3.5 kg to 15 kg, 4 kg to 25 kg, 4 kg to 22.5 kg, 4 kg to 20 kg, 4 kg to 17.5 kg, 4 kg to 15 kg, 4.5 kg to 25 kg, 4.5 kg to 22.5 kg, 4.5 kg to 20 kg, 4.5 kg to 17.5 kg, 4.5 kg to 15 kg, 5 kg to 25 kg, 5 kg to 22.5 kg, 5 kg to 20 kg, 5 kg to 17.5 kg, or 5 kg to 15 kg. In terms of the upper limit, the tow can 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 the lower limit, the tow may have a breaking strength greater than 3.5 kg, e.g., greater than 4 kg, greater than 4.5 kg, or greater than 5 kg.

In some embodiments of the present disclosure, the tow band may include two or more types of fibers. In some embodiments, the two or more types of fibers may vary based on dpf, cross-sectional shape, composition, processing prior to forming the tow band, or any combination thereof. Examples of suitable additional fibers include, but are not limited to, carbon fiber, activated carbon fiber, natural fiber, synthetic fiber, or any combination thereof. Further examples include some cellulose acetate tows containing fillers and some cellulose acetate tows without fillers. The weight ratio of tows with fillers to tows without fillers may range from 1:99 to 99:1, e.g., 1:75 to 75:1, 1:50 to 50:1, 1:25 to 25:1, 1:10 to 10:1, 1:5 to 5:1, 1:3 to 3:1, 1:2 to 2:1, or approximately 1:1. In some embodiments, the cellulose acetate is present in a weight ratio greater 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 therebetween). It is contemplated that different tows may contain different types of fillers, ultimately combined to form a single tow band. For example, some tow filaments may contain monosaccharides, while other tow filaments may contain different fillers, such as polysaccharides or starches. Additionally, the tow may contain fillers integral to the tow, e.g., added to the flake, powder, or dope, as well as fillers added later in the manufacturing process, such as cellulose or certain starches.

Some embodiments of the present disclosure may include crimping the tow band to form a crimped tow band. Crimping the tow band may include using any suitable crimping technique known to those skilled in the art. These techniques may include various devices, including, but not limited to, stuffer boxes or gears. Non-limiting examples of crimping devices and the mechanisms by which they operate can be found in U.S. Patent Nos. 7,610,852 and 7,585,441, the entire contents and disclosures of which are incorporated herein by reference. A suitable stuffer box crimper may have smooth or grooved crimper nip rolls, textured crimper nip rolls, top flaps, bottom flaps, or any combination thereof.

The crimp configuration can play a role in the processability of the final bale. Examples of crimp configurations may include, but are not limited to, horizontal, vertical, some degree between horizontal and vertical, random, or any combination thereof. As used herein, the term "horizontal" when describing a crimp configuration means a crimp or fiber bending in the plane of the tow band. As used herein, the term "vertical" when describing a crimp configuration means a crimp that protrudes outside the plane of the tow band and is perpendicular to the plane of the tow band. Note that the terms horizontal and vertical refer to the general overall crimp configuration and may have deviations from said configurations up to +/- 30 degrees.

In some embodiments of the present disclosure, the crimped tow band may include fibers having a first crimp configuration and fibers having a second crimp configuration.

In some embodiments of the present disclosure, the crimped tow band may include fibers having at least a vertical crimp configuration near the ends and fibers having at least a vertical crimp configuration near the center. In some embodiments, the crimped tow band may include fibers having at least a horizontal crimp configuration near the ends and fibers having a horizontal crimp configuration near the center.

The crimp configuration can be important with respect to the processability of the final bale in subsequent processing steps; for example, a horizontal crimp configuration may provide better fiber bonding than a vertical crimp configuration unless additional steps are taken to enhance bonding. Methods for crimping tow bands having substantially the latter crimp configuration are disclosed, for example, in U.S. Patent Application Publication Nos. 2013/0115452 and 2015/0128964, each of which is incorporated herein in its entirety.

In some embodiments of the present disclosure, fibers may be bonded to one another to provide better processability of the final bale. While adhesive additives may be used with either crimp configuration, using an adhesive additive with a vertical crimp configuration may be advantageous. In some embodiments, the adhesion may include an adhesive additive on and/or in the fiber. Examples of such adhesive additives may include, but are not limited to, binders, adhesives, resins, tackifiers, or any combination thereof. Note that any additive described herein or others capable of bonding two fibers together may be used, including, but not limited to, active particles, active compounds, ionic resins, zeolites, nanoparticles, ceramic particles, softeners, plasticizers, pigments, dyes, fragrances, fragrances, controlled-release vesicles, surface modifiers, lubricants, emulsifiers, vitamins, peroxides, biocides, antifungals, antibiotics, antistatic agents, flame retardants, antifoaming agents, decomposition agents, conductivity modifiers, stabilizers, or any combination thereof. Some embodiments of the present disclosure may include 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 formation of the tow band), applying the adhesive additives to the tow band (before, after, and/or during crimping), or any combination thereof.

The adhesive additive may be included in and/or on the fibers at a concentration sufficient to bond the fibers together at multiple contact points to provide better processability of the final bale. The concentration of adhesive additive used may depend on the type of adhesive additive and the strength of the bond it 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 of the final bale. Note that for additives used for more than adhesion, the concentration in the tow band of the final bale may be higher, e.g., up to 25%.

Additionally, some embodiments of the present disclosure may include heating the fibers before, after, and/or during crimping. While the heating may be used in combination with any crimp configuration, it may be advantageous to use the heating in conjunction with a vertical crimp configuration. The heating may involve exposing the fibers of the tow band to steam, an aerosolized compound (e.g., a plasticizer), a liquid, a heated fluid, a direct heat source, an indirect heat source, an irradiation source that generates heat in additives (e.g., nanoparticles) in the fibers, or any combination thereof.

Some embodiments of the present disclosure may include conditioning the crimped tow band. Conditioning may be used to produce a crimped tow band having a residual acetone content of 0.5% w/w or less. Conditioning may be used to achieve a crimped tow band having a residual moisture content of 8% w/w or less. Conditioning may involve exposing the fibers of the crimped tow band to steam, an aerosolized compound (e.g., a plasticizer), a liquid, a heated fluid, a direct heat source, an indirect heat source, an irradiation source that generates heat in additives (e.g., nanoparticles) in the fibers, or any combination thereof.

UCE is the amount of work required to uncrimp a fiber. UCE, as reported below, is sampled before bailing, i.e., after drying and before bailing. UCE, as used herein, is measured as follows: (20 minutes prior to conventional calibration) on a warmed-up Instron tensile tester (Model 1130, crosshead gear - Gear #R1940-1 and R940-2, Instron Series IX - Version 6 data acquisition and analysis software, Instron 50 Kg maximum capacity load cell, Instron top roller assembly, 1 inch x 4 inch x 1/8 inch thick high grade Buna-N 70 Shore Using a 100-mm durometer rubber grip face, an approximately 76 cm long pre-conditioned tow sample (pre-conditioned for 24 hours at 22°C ± 2°C and 60% ± 2% relative humidity) is looped over the center of the top roller, spread evenly across it, and pre-tensioned by gently pulling to 100 g ± 2 g (per display), and each end of the sample is secured in the lower grip (at the highest available pressure not exceeding the manufacturer's recommendation) to produce a 50 cm gauge length (measured from the top of the rubber grip), then tested to break at a crosshead speed of 30 cm/min. This test is repeated until three acceptable tests are obtained, and the average of the three data points from these tests is reported. The energy (E) limit is 0.220 kg to 10.0 kg. The displacement (D) has a preset point of 10.0 kg. UCE is calculated by the following formula: UCE (gcm/cm) = (E*1000)/((D*2)+500). Breaking strength can be calculated using the same test and the following formula: BS = L, where L is the load (kg) at maximum load. In certain embodiments of the present disclosure, the UCE value (gcm/cm) can range from 190 to 400, for example, from 200 to 300, for example, 290. In certain embodiments of the present disclosure, the breaking strength can range from 3.5 kg to 25 kg, for example, from 4 kg to 20 kg, from 4.5 kg to 15 kg, or from 5 kg to 12 kg.

Cigarette Filters Degradable cigarette filters generally include a filter element (i.e., a filter plug) made of opened cellulose acetate tow containing a filler, and a plug wrap encasing the filter element. The cellulose acetate tow is delivered as a bale to a filter manufacturer. The tow is then opened, i.e., bloomed, in a rod-making facility to form a filter rod and, ultimately, a cigarette filter. Various properties are desirable in cigarette filters, including firmness, pressure drop, pressure drop variability, unpackability, fly, and unclamping energy. The fillers described herein, and the amounts used, may be selected to balance these properties with the degradability of the cigarette filter.

Embodiment [Embodiment 1]
A cellulose acetate tow band, comprising: a) a cellulose acetate having a degree of substitution (DS) greater than 1.3; and b) a filler; wherein the filler has a greater decomposition rate than the cellulose acetate.

[Embodiment 2]
The tow band of claim 1, wherein the filler comprises a monosaccharide, a polysaccharide, an ester of a polysaccharide, a hydrolyzed polysaccharide, an oligosaccharide, or a combination thereof.

[Embodiment 3]
The tow band of claim 1 or 2, wherein the filler comprises dextran, hydrolyzed starch, modified and hydrolyzed starch, hemp, cellulose, or a combination thereof.

[Embodiment 4]
The tow band according to any one of claims 1 to 3, wherein the filler is present in an amount of 0.1 to 99.9 wt%, based on the total weight of the tow band.

[Embodiment 5]
The tow band according to any one of claims 1 to 4, wherein the filler is present in an amount of 0.1 to 75 wt%, based on the total weight of the tow band.

[Embodiment 6]
The tow band according to any one of claims 1 to 5, wherein the filler is present in an amount of 0.1 to 50 wt%, based on the total weight of the tow band.

[Embodiment 7]
7. The tow band according to any one of claims 1 to 6, wherein the filler is present in an amount of 0.1 to 25 wt%, based on the total weight of the tow band.

[Embodiment 8]
The tow band according to any one of claims 1 to 7, wherein the decomposition rate of the filler is at least 3% higher than that of the cellulose acetate.

[Embodiment 9]
The tow band according to any one of claims 1 to 8, wherein the decomposition rate of the filler is at least 10% higher than that of the cellulose acetate.

[Embodiment 10]
The tow band according to any one of claims 1 to 9, wherein the decomposition rate of the filler is at least 15% higher than that of the cellulose acetate.

[Embodiment 11]
11. The tow band of any one of claims 1 to 10, wherein the tow band comprises a weight ratio of the cellulose acetate to the filler of 1:99 to 99:1.

[Embodiment 12]
12. The tow band of any one of claims 1 to 11, wherein the tow band comprises a weight ratio of the cellulose acetate to the filler of 1:50 to 50:1.

[Embodiment 13]
13. The tow band of any one of claims 1 to 12, wherein the tow band comprises a weight ratio of the cellulose acetate to the filler of 1:25 to 25:1.

[Embodiment 14]
The tow band according to any one of claims 1 to 13, wherein the tow band comprises cellulose acetate in an amount of 0.1 to 99.9 wt%, based on the total weight of the tow band.

[Embodiment 15]
15. The tow band according to any one of claims 1 to 14, wherein the cellulose acetate has a degree of substitution of 2 to 2.9.

[Embodiment 16]
16. The tow band of any one of claims 1 to 15, wherein the tow band comprises 0.01 to 25 wt. % of an additive, based on the total weight of the tow band.

[Embodiment 17]
A cigarette filter comprising a filter element including an opened tow, wherein the opened tow comprises the tow band according to any one of claims 1 to 16.

[Embodiment 18]
A method for forming a cigarette filter according to claim 17, comprising: a) providing a tow band of the cellulose acetate; b) opening the tow band; and c) forming the opened tow band into a filter rod.

[Embodiment 19]
19. The method of claim 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 the dope to form a plurality of tow filaments; and c) bundling the plurality of tow filaments to form a tow band.

[Embodiment 20]
19. The method of claim 18, wherein the tow band is formed by: a) combining cellulose acetate and the filler to form flakes; b) combining the flakes with a solvent to form a dope; c) solvent-spinning the dope to form a plurality of tow filaments; and d) bundling the plurality of tow filaments to form a tow band.

Although the present invention has been described in detail, modifications within the spirit and scope of the present invention will be readily apparent to those skilled in the art. It should be understood that the aspects of the present invention and portions and various features of the various embodiments recited above and/or in the appended claims may be combined or interchanged in whole or in part. In the above description of various embodiments, those embodiments that refer to other embodiments may be appropriately combined with other embodiments recognized by those skilled in the art. Furthermore, those skilled in the art will recognize that the above description is by way of example only and is not intended to limit the present invention.
The claims as filed are as follows:
[Claim 1]
A cellulose acetate tow band, comprising:
a) cellulose acetate having a degree of substitution (DS) greater than 1.3; and b) a filler, said filler having a greater decomposition rate than cellulose acetate;
a cellulose acetate tow band comprising:
[Claim 2]
The tow band of claim 1 , wherein the filler comprises a monosaccharide, a polysaccharide, an ester of a polysaccharide, a hydrolyzed polysaccharide, an oligosaccharide, or a combination thereof.
[Claim 3]
The tow band of claim 1 or 2, wherein the filler comprises dextran, hydrolyzed starch, modified and hydrolyzed starch, hemp, cellulose, or a combination thereof.
[Claim 4]
The tow band according to any one of claims 1 to 3, wherein the filler is present in an amount of 0.1 to 99.9 wt%, 0.1 to 75 wt%, 0.1 to 50 wt%, or 0.1 to 25 wt%, based on the total weight of the tow band.
[Claim 5]
The tow band according to any one of claims 1 to 4, wherein the decomposition rate of the filler is at least 3% higher than that of the cellulose acetate.
[Claim 6]
A tow band according to any one of claims 1 to 5, wherein the decomposition rate of the filler is at least 10% higher than that of the cellulose acetate, or at least 15% higher than that of the cellulose acetate.
[Claim 7]
The tow band according to any one of claims 1 to 6, wherein the tow band comprises the cellulose acetate to the filler in a weight ratio of 1:99 to 99:1, 1:50 to 50:1, or 1:25 to 25:1.
[Claim 8]
The tow band according to any one of claims 1 to 7, wherein the tow band contains cellulose acetate in an amount of 0.1 to 99.9 wt%, based on the total weight of the tow band.
[Claim 9]
The tow band according to any one of claims 1 to 8, wherein the cellulose acetate has a degree of substitution of 1.3 to 2.9, or 2 to 2.9.
[Claim 10]
The tow band according to any one of claims 1 to 9, wherein the tow band comprises 0.01 to 25 wt.% of an additive, based on the total weight of the tow band.
[Claim 11]
A cigarette filter comprising a filter element including an opened tow, wherein the opened tow comprises the tow band according to any one of claims 1 to 10.
[Claim 12]
12. A method for forming the cigarette filter of claim 11, said method comprising:
a) providing a cellulose acetate tow band;
b) opening the tow band; and c) forming the opened tow band into a filter rod.
A method comprising:
[Claim 13]
The tow band is
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) bundling the plurality of tow filaments to form a tow band.
The method of claim 12 , wherein the compound is formed by:
[Claim 14]
The tow band is
a) combining cellulose acetate and the filler to form flakes;
b) combining the flakes with a solvent to form a dope;
c) solvent-spinning the dope to form a plurality of tow filaments; and d) bundling the plurality of tow filaments to form the tow band.
The method of claim 12 , wherein the compound is formed by:

Claims (10)

A cellulose acetate tow band, comprising:
a) cellulose acetate having a degree of substitution (DS) of acetic acid greater than 1.3;
b) a filler comprising galactose, ribose, xylose, an oligosaccharide, cellulose, hemicellulose, hyaluronic acid, alginate, guar gum, chitin, chondroitin, hemp seed polysaccharide, or a combination thereof , said filler having a greater degradation rate than said cellulose acetate and present in an amount of 0.1 to 15% by weight of said tow band ; and
plasticizer
a cellulose acetate tow band comprising: The tow band of claim 1 , wherein the decomposition rate of the filler is at least 3% higher than that of the cellulose acetate. A tow band according to any one of claims 1 to 2 , wherein the decomposition rate of the filler is at least 10% higher than that of the cellulose acetate. The tow band according to any one of claims 1 to 3 , wherein the tow band comprises the cellulose acetate to the filler in a weight ratio of 1:99 to 99:1 . The tow band according to any one of claims 1 to 4 , wherein the tow band contains cellulose acetate in an amount of 0.1 to 99.9 wt%, based on the total weight of the tow band. The tow band according to any one of claims 1 to 5 , wherein the cellulose acetate has a degree of acetic acid substitution of 1.3 to 2.9 . A cigarette filter comprising a filter element including an opened tow, wherein the opened tow comprises the tow band according to any one of claims 1 to 6 . 8. A method for forming the cigarette filter of claim 7 , said method comprising:
a) providing a cellulose acetate tow band;
b) opening the tow band; and c) forming the opened tow band into a filter rod.
A method comprising: The tow band is
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) bundling the plurality of tow filaments to form a tow band.
The method of claim 8 , wherein the compound is formed by The tow band is
a) combining cellulose acetate and the filler to form flakes;
b) combining the flakes with a solvent to form a dope;
c) solvent-spinning the dope to form a plurality of tow filaments; and d) bundling the plurality of tow filaments to form the tow band.
The method of claim 8 , wherein the compound is formed by