Lyocell material, smoking article and method of manufacturing thereof

Abstract

This disclosure relates to lyocell materials, smoking articles including the thereof, and methods for preparing said lyocell materials, wherein the lyocell materials can be prepared from a stock solution comprising a cellulose slurry and N-methylmorpholine-N-oxide (NMMO), wherein the cellulose slurry can have a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight.

Description

Technical Field

[0001] This application is based on and claims priority to Korean Patent Application No. 10-2023-0178048 filed with the Korean Intellectual Property Office on December 8, 2023, and Korean Patent Application No. 10-2024-0178343 filed with the Korean Intellectual Property Office on December 4, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] This disclosure relates to: a lyocell material having good spinnability, appearance, and cigarette filter cutability, as well as monofilament strength suitable for use in cigarette filters; a cigarette filter comprising the lyocell material; and a method for preparing the lyocell material. Background Technology

[0003] To date, cellulose acetate fiber has primarily been used as a material for cigarette filters. Although cellulose acetate is known to be biodegradable, cigarette filters made from it retain their original shape for approximately one to two years after being buried in soil, and require a considerable amount of time to fully biodegrade. As a synthetic plastic, cellulose acetate decomposes into microplastics through physical and photochemical reactions when exposed to the external environment. Microplastics are known to be harmful substances that damage ecosystems.

[0004] Therefore, research is underway across various fields to find chemically unmodified, biodegradable materials for smoking products as alternatives to cellulose acetate. Recently, cigarette filters made from lyocell materials have been investigated; however, there remains a need for lyocell materials suitable for continuous manufacturing processes in cigarette filters. Summary of the Invention

[0005] Technical issues

[0006] The purpose of this disclosure is to provide a lyocell material having good spinnability, appearance, and cigarette filter cutability, as well as monofilament strength suitable for filters used in smoking products; a smoking product comprising the lyocell material; and a method for preparing the lyocell material.

[0007] Technical solution

[0008] According to one aspect, a lyocell material is provided, which is prepared from a dope solution comprising cellulose slurry and N-methylmorpholine-N-oxide (NMMO). The cellulose slurry has a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight.

[0009] Lyocell material may include at least one lyocell monofilament.

[0010] Lyocell multifilament can include at least one Lyocell monofilament.

[0011] According to another aspect, a smoking product containing lyocell material is provided.

[0012] According to another aspect, a method for preparing a lyocell material is provided, the method comprising: spinning a dope solution containing cellulose slurry and N-methylmorpholine-N-oxide (NMMO) through a spinneret; The spinning solution is solidified to obtain Lyocell multifilament; The Lyocell multifilaments are washed and treated with an emulsion; and The multifilaments treated with emulsion are crimped to obtain crimped filament bundles. The cellulose slurry has a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight.

[0013] Beneficial effects

[0014] According to one aspect, by using a slurry with a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight as raw material, lyocell material not only meets the range of monofilament strength suitable for use as a filter tip in smoking products, but also enables the production of cigarette filters with good cutability. Detailed Implementation

[0015] The inventive concept, which will be described more fully below, can have various variations and embodiments, and specific embodiments will be shown and described in more detail in the accompanying drawings. However, the inventive concept should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments should be understood to cover all variations, equivalents, or alternatives included within the scope of the inventive concept.

[0016] The terminology used below is for the purpose of describing particular embodiments only and is not intended to limit the inventive concept.

[0017] As used herein, the singular form is also intended to include the plural form, unless the context clearly indicates otherwise. As used herein, unless otherwise indicated, the terms “comprising,” “including,” or “having” indicate the presence of certain features, figures, steps, operations, components, parts, ingredients, materials, or any combination thereof described in the specification, but do not exclude the presence or addition of one or more other features, figures, steps, operations, components, parts, ingredients, materials, or combinations thereof.

[0018] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms such as those defined in common dictionaries shall be interpreted as having the same meaning as they have in this specification and related art, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0019] In this specification, "smoking articles" can refer to articles capable of generating aerosols, such as cigarettes or cigars. In this respect, smoking articles may include aerosol-generating materials or aerosol-forming matrices. Furthermore, smoking articles may include solid materials based on tobacco raw materials, such as reconstituted tobacco, cut tobacco, or cast tobacco. Additionally, smoking articles may include volatile compounds.

[0020] Unless otherwise defined herein, when the properties of lyocell materials, filters for smoking products, or related components or configurations are affected by temperature, the temperature at which such properties are identified or measured may be room temperature. Without intentional cooling or heating, room temperature may be, for example, 10°C to 35°C, specifically 15°C to 35°C, 20°C to 30°C, or about 25°C.

[0021] In this specification, the term "different" can indicate that entities are different in a qualitative sense. For example, "A and B are different" can mean that although A and B are the same in quantity, A and B are qualitatively distinguishable; or that A and B are different in quantity and are also qualitatively distinguishable. The term "qualitative" can refer to non-quantitative properties. For example, differences in color, shape, texture, structure, or composition can fall under the category of "qualitative" differences.

[0022] In this specification, the term "crimp" can refer to a wavy, crimped, or undulating configuration inherent in or imparted by mechanical, thermal, and / or chemical processes to materials such as fibers, filaments, multifilaments, or yarns. A crimp can be characterized by a periodic deviation along the length of the material, fiber, filament, multifilament, and / or yarn relative to a linear axis. A crimp in a material, fiber, filament, multifilament, and / or yarn can be defined as a repeating unit of the periodic deviation. The presence of crimp affects the properties of the material and textiles made from it, such as elasticity, bulk, resilience, and texture.

[0023] In this specification, the term "degree of polymerization" (DP) can refer to the number of monomer units and / or repeating units in a macromolecule, polymer, or oligomer molecule. DP can be represented as M. n / M0, where M n It is the number-average molecular weight of a macromolecule, polymer, or oligomer, and M0 is the molecular weight of a monomer or repeating unit.

[0024] The following description will provide a more detailed account of lyocell materials according to exemplary embodiments, smoking articles containing lyocell materials, and methods for manufacturing lyocell materials.

[0025] [Lyocell Material]

[0026] In this disclosure, the term "lyocell material" refers to a monofilament material or an aggregate of monofilaments (multifilaments) obtained by spinning, coagulating, and drying a stock solution obtained by dissolving cellulose slurry in an N-methylmorpholine-N-oxide (NMMO) solution. It should be understood in the art that, as used herein, the term "lyocell material" is different from "cellulose acetate material".

[0027] According to one aspect, the lyocell material can be prepared from a stock solution comprising a cellulose slurry and N-methylmorpholine-N-oxide (NMMO), wherein the cellulose slurry has a CED viscosity of 4.0 to 11.0 and, based on the total weight of the cellulose slurry, contains less than 5% by weight hemicellulose, 1 ppm to less than 30 ppm by weight of Fe, and 1 ppm to less than 100 ppm by weight of Si.

[0028] CED viscosity was measured according to TAPPI standard T230 om-94.

[0029] Hemicellulose content was measured according to KS M 7044:2016.

[0030] Inorganic components (e.g., Fe and Si) in the slurry were measured using ICP-OES (PerkinElmer Avio-550).

[0031] Based on 100% by weight of the total weight of all cellulose in the pulp and / or relative to the total weight of the cellulose pulp, the α-cellulose content of the cellulose pulp can be from 85% by weight to 97% by weight.

[0032] Based on 100% by weight of the total weight of all cellulose in the pulp and / or relative to the total weight of the cellulose pulp, the hemicellulose content of the cellulose pulp can be more than 1% by weight and less than 5% by weight.

[0033] By using cellulose pulp with a specific 0.5% CED viscosity, hemicellulose content, and inorganic matter content as raw material, the final Lyocell material can exhibit improved processability and operability.

[0034] Spinability can be improved by adjusting the CED viscosity of the cellulose slurry used as the raw material for lyocell to between 4.0 and 11.0. If the CED viscosity is below 4.0, filament breakage may occur repeatedly during the spinning of the lyocell solution through a spinneret, leading to deterioration of spinning processability and making continuous filament production difficult. If the viscosity exceeds 11.0, excessively high pressure may be required to extrude the spinning solution, or the spinneret nozzle may become clogged.

[0035] Stable and continuous production of lyocell filaments can be achieved by adjusting the hemicellulose content of the raw cellulose pulp used in lyocell material to less than 5% by weight. If the hemicellulose content is above 5% by weight, not only will spinneret contamination caused by hemicellulose released from the NMMO solvent become a problem, but the increased hemicellulose content in the lyocell material will also lead to a decrease in filament strength, potentially making it unsuitable for use as a filter in smoking products. Furthermore, from an NMMO recycling perspective, removing the hemicellulose released from the NMMO solvent may be necessary, which would increase the cost and burden of the NMMO recycling / regeneration system.

[0036] By controlling the Fe content in the cellulose pulp of lyocell material to less than 30 ppm by weight, the decomposition reaction of the pulp caused by NMMO can be accelerated, thereby preventing discoloration of the filaments and a decrease in filament tenacity caused by NMMO discoloration. If the Fe content in the cellulose pulp is above 30 ppm by weight, the filament tenacity decreases, resulting in poor dicing properties when used in cigarette filter manufacturing, making it difficult to apply to filter manufacturing processes.

[0037] By controlling the Si content of the cellulose pulp used as a raw material for lyocell to less than 100 ppm by weight, discoloration of the filaments caused by NMMO discoloration and a decrease in filament specific strength can be prevented. If the Si content in the cellulose pulp is above 100 ppm by weight, the filament specific strength decreases, resulting in poor dicing properties when forming cigarette filters, making them difficult to apply in filter manufacturing processes.

[0038] Conventionally, lyocell staple fibers are typically manufactured using slurries with a hemicellulose content of 5% by weight or more, resulting in relatively low filament strength. However, the lyocell material of one embodiment of this disclosure can achieve sufficient monofilament strength for use in cigarette filters by employing a slurry with less than 5% by weight of hemicellulose. On the other hand, simply reducing the hemicellulose content is insufficient to achieve the filament cutability required for cigarette filters. The inventors of this invention have discovered that by controlling the content of Fe and Si, which exist in trace amounts as inorganic components in the slurry, the reduction in filament specific strength can be suppressed, thereby improving cutability during the cigarette filter manufacturing process. Based on this understanding, the inventors have completed the lyocell material of this disclosure.

[0039] Furthermore, from a smoker's perspective, cigarette filters are typically preferred to be white for aesthetic reasons; therefore, conventional lyocell manufacturing processes have been designed to pass the filaments through a whitening stage. However, the inventors have discovered that controlling the Fe and Si content in the slurry can suppress discoloration caused by NMMO, thereby enabling the desired appearance (i.e., color) of cigarette filters to be produced. Based on this understanding, the inventors have completed the lyocell material disclosed herein.

[0040] Unbound by theory, by using cellulose slurries with specific CED viscosity, hemicellulose content, and Fe and Si content as raw material cellulose slurries, Lyocell materials can achieve an appearance and monofilament strength suitable for cigarette filters while preventing a decrease in filament strength, and also possess the cutability required for cigarette filter manufacturing processes.

[0041] According to one embodiment, the hemicellulose content of the cellulose pulp can be 4% by weight or less, based on the total weight of the cellulose pulp. For example, the hemicellulose content of the cellulose pulp can be 3.9% by weight or less, 3.8% by weight or less, or 3.7% by weight or less. Although it is possible to make cellulose pulp hemicellulose-free, in practice, refining cellulose pulp to be hemicellulose-free involves complex steps and high costs, and is therefore generally not desirable.

[0042] According to one embodiment, the cellulose slurry may include various inorganic substances introduced during the extraction process. For example, the cellulose slurry may include inorganic substances such as iron (Fe), copper (Cu), and silicon (Si). Conventional lyocell studies have investigated the strength of lyocell multifilaments in relation to the hemicellulose content of the cellulose slurry, but the control of the inorganic substance content has not been studied.

[0043] According to one embodiment, the inorganic content of cellulose pulp can be controlled by contacting the pulp with a dilute acid solution, such as sulfurous acid, hydrochloric acid, or sulfuric acid solution, to form and remove inorganic salts; however, this disclosure is not limited thereto.

[0044] According to one embodiment, the cellulose pulp may contain 1 ppm to 20 ppm of Fe by weight relative to the total weight of the cellulose pulp. For example, the cellulose pulp may contain 1 ppm to 19 ppm, 1 ppm to 18 ppm, 1 ppm to 17 ppm, 1 ppm to 16 ppm, 1 ppm to 15 ppm, 1 ppm to 14 ppm, 1 ppm to 13 ppm, 1 ppm to 12 ppm, 1 ppm to 11 ppm, 1 ppm to 10 ppm, 1 ppm to 9 ppm, 1 ppm to 8 ppm, 1 ppm to 7 ppm, 1 ppm to 6 ppm, 1 ppm to 5 ppm, 1 ppm to 4 ppm, 1 ppm to 3 ppm, or 1 ppm to 2 ppm of Fe by weight.

[0045] According to one embodiment, the cellulose pulp may contain 1 ppm to 100 ppm of Si by weight relative to the total weight of the cellulose pulp. For example, the cellulose pulp may contain 1 ppm to 90 ppm, 1 ppm to 80 ppm, 1 ppm to 70 ppm, 1 ppm to 60 ppm, 1 ppm to 50 ppm, 1 ppm to 40 ppm, 1 ppm to 30 ppm, 1 ppm to 20 ppm, or 1 ppm to 10 ppm of Si by weight, but is not limited to these ranges, and any lower and upper limits of the above values ​​may be combined to form a suitable range.

[0046] According to one embodiment, the cellulose pulp may contain 1 ppm to 10 ppm of Fe and 1 ppm to 90 ppm of Si by weight, relative to the total weight of the cellulose pulp. For example, the cellulose pulp may contain 1 ppm to less than 5 ppm of Fe and 5 ppm to 80 ppm of Si by weight.

[0047] According to one embodiment, the degree of polymerization of the cellulose slurry can be from 600 to 1,700. In some embodiments, the degree of polymerization may refer to the number of repeating units and / or monomer units in the cellulose and / or hemicellulose contained in the cellulose slurry.

[0048] According to one embodiment, the lyocell material may comprise more than one lyocell monofilament, and each of these monofilaments may have a strength of 0.265 N / tex to 0.706 N / tex (3 g / d to 8 g / d). For example, the strength of the monofilament may be 0.274 N / tex to 0.698 N / tex (3.1 g / d to 7.9 g / d), 0.283 N / tex to 0.689 N / tex (3.2 g / d to 7.8 g / d), 0.291 N / tex to 0.680 N / tex (3.3 g / d to 7.7 g / d), 0.300 N / tex to 0.671 N / tex (3.4 g / d to 7.6 g / d), or 0.309 N / tex to 0.662 N / tex (3.5 g / d to 7.5 g / d). In this specification, the term "strength" refers to the strength and / or specific strength of a textile.

[0049] Strength can be measured by the following method: After pre-drying the multifilament sample at 110°C for 2 hours, allow the sample to stand under the standard conditions described in KS K0901 for at least 24 hours to reach moisture equilibrium. Then separate the monofilament sample from the multifilament. Perform tensile strength testing on the separated monofilament sample using a low-speed elongation tensile tester (Instron) at a tensile speed of 60 mm / min.

[0050] Lyocell material, when possessing monofilament strength within the aforementioned range, can be readily processed into cigarette filters. If the monofilament strength is below 0.265 N / tex (3 g / d), the resulting cigarette filter is prone to collapse when bitten by a smoker, making it unsuitable for use as a filter. If the monofilament strength exceeds 0.706 N / tex (8 g / d), the high tensile strength during cigarette filter manufacturing hinders filter cutting, resulting in poor cut surfaces.

[0051] According to one embodiment, lyocell material can be curled. As will be described in more detail below in the manufacturing process of lyocell material, lyocell material can be curled by a curling process, and thus possesses the draw resistance and filtration capacity required when used as a cigarette filter material. Furthermore, the degree of fiber opening during filter manufacturing is improved, which is beneficial for continuous filter production.

[0052] According to one embodiment, the lyocell material can have 25.4 to 127 curls per centimeter (10 to 50 curls per inch).

[0053] According to one embodiment, the lyocell material can be in the form of lyocell tow. A lyocell tow refers to a ribbon-like aggregate of lyocell multifilaments, which is used as feed material in the manufacturing process of cigarette filters.

[0054] According to one embodiment, the lyocell tow can have an irregular cross-section. "Irregular cross-section" can refer to any cross-sectional shape that deviates from a standard circular shape. For example, the cross-sectional shape can be Y-shaped, rectangular, star-shaped, leaf-shaped, or hexagonal, or have other polygonal cross-sections. From the perspective of application to cigarette filters, the lyocell tow can preferably have a Y-shaped cross-section.

[0055] According to one embodiment, the total fineness of the lyocell tow can be from 1.67 g / m to 6.11 g / m (15,000 to 55,000 denier).

[0056] According to one embodiment, lyocell tow can be used to manufacture filters for smoking products.

[0057] [Preparation methods for Lyocell materials]

[0058] According to one aspect, a method for preparing a lyocell material includes: spinning a dope solution containing cellulose slurry and N-methylmorpholine-N-oxide (NMMO) through a spinneret; coagulating the spun dope solution to obtain lyocell multifilaments; washing the lyocell multifilaments and treating them with an emulsion; and crimping the emulsion-treated multifilaments to obtain crimped filament bundles, wherein the cellulose slurry has a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight. The CED viscosity is measured according to TAPPI standard T230 om-94.

[0059] The preparation method of lyocell material according to one embodiment will be described in more detail below.

[0060] <(a) Lyocell solution spinning process>

[0061] Lyocell spinning dopes can be prepared by dissolving cellulose slurry in an N-methylmorpholine-N-oxide (NMMO) solution having the above-mentioned CED viscosity of 4.0 to 11.0 and containing less than 5% by weight hemicellulose, at least 1 ppm and less than 30 ppm by weight of Fe, and at least 1 ppm and less than 100 ppm by weight of Si, based on the total weight of the cellulose slurry.

[0062] According to one embodiment, the content of cellulose slurry in the spinning solution can be from 5% to 15% by weight, based on 100% by weight of the total weight of the spinning solution. If the content of cellulose slurry is too low, it may be difficult to achieve the characteristics of lyocell fiber; on the other hand, if the content exceeds the above range, it may be difficult to dissolve the slurry in a solvent. In view of the above, the content of cellulose slurry in the spinning solution can be 6% or more by weight, 7% or more by weight, 8% or more by weight, 9% or more by weight, or 10% or more by weight, and its upper limit can be, for example, 14% or less by weight, 13% or less by weight, 12% or less by weight, 11% or less by weight, 10% or less by weight, or 9% or less by weight.

[0063] According to one embodiment, the spinning solution may include an aqueous solution of N-methylmorpholine-N-oxide (NMMO). Taking into account factors such as the degree of cellulose solubility and process temperature, the aqueous solution may, for example, include 80 to 95 parts by weight of N-methylmorpholine-N-oxide and 5 to 20 parts by weight of water.

[0064] According to one embodiment, the α-cellulose content of cellulose or cellulose pulp may be from 85% to 97% by weight relative to 100% by weight of total cellulose.

[0065] According to one embodiment, the hemicellulose content of cellulose or cellulose pulp can be 1% by weight and less than 5% by weight relative to 100% by weight of total cellulose. By adjusting the hemicellulose content to the above range, stable physical properties (e.g., mechanical properties such as tensile strength or elongation) and processability of lyocell materials can be more easily achieved.

[0066] In the spinning process, there are no particular restrictions on the shape of the spinneret used to discharge the spinning solution. For example, an annular spinneret can be used.

[0067] The nozzle temperature of the spinneret can be appropriately selected by those skilled in the art, taking into account the concentration of the spinning solution and the desired properties of the filament. For example, spinning can be carried out at a temperature of 100°C to 120°C or 100°C to 110°C.

[0068] The spinning solution discharged through the spinneret can undergo the coagulation process described below.

[0069] <(b) Processes for solidification and obtaining multifilament>

[0070] The spinning solution discharged from the spinneret can solidify to obtain Lyocell multifilament.

[0071] Coagulation can be achieved by contacting the spinning solution with air and / or a coagulating solution.

[0072] According to one embodiment, coagulation may include: a primary coagulation process of supplying cooling air to the spinning solution; and a secondary coagulation process of immersing the primary coagulated spinning solution in a coagulation liquid for coagulation.

[0073] The primary solidification process can be carried out in the space between the spinneret and the solidification bath (air gap region). In the air gap region, cooling air can be supplied from the inside of the spinneret to the outside, but is not limited to this; cooling air can also be supplied from the outside to the inside or simultaneously in both directions. Alternatively, the primary solidification process can be performed by appropriately referring to air quenching methods known to those skilled in the art.

[0074] According to one embodiment, the upper limit of the temperature of the cooling air used in a single solidification process can be, for example, below 15°C. For example, the cooling air can be air with a temperature below 14°C, below 13°C, below 12°C, below 11°C, or below 10°C. If the temperature exceeds this range, the spinning solution may not be able to solidify sufficiently by air, and the processability associated with spinning will deteriorate.

[0075] The lower limit of the cooling air temperature can be determined by considering spinning processability and / or the cross-sectional uniformity of the filament. For example, if the cooling air temperature is below 4°C, the spinneret surface will cool, resulting in irregular filament surfaces and deteriorating spinning processability. Therefore, the cooling air temperature can be above 5°C, 6°C, 7°C, 8°C, or 9°C.

[0076] The supply of cooling air can be adjusted to take into account adequate solidification, spinning processability, and its impact on filament properties. For example, the cooling air can be supplied at 70 Nm. 3 / h to 400 Nm 3 An airflow rate of / h is supplied to the extruded spinning solution. More specifically, the airflow rate can be 100 Nm. 3 / h or more, 150 Nm 3 / h or more, 200 Nm 3 / h or above, or 250 Nm 3 / h or higher, and the upper limit of the airflow rate can be, for example, 350 Nm 3 / h or less, 300 Nm 3 / h or less, 250 Nm 3 / h or less, 200Nm 3 / h or less, or 150 Nm 3 / h and below.

[0077] After this primary coagulation, the cooled spinning solution can be supplied to a coagulation tank or coagulation bath containing a coagulating solution (secondary coagulation). For suitable coagulation, the temperature of the coagulating solution can be, for example, below 30°C or below 25°C. Alternatively, the temperature of the coagulating solution can be at least 10°C, at least 15°C, or at least 20°C. Maintaining this temperature allows for a suitable coagulation rate.

[0078] There are no particular limitations on the type of coagulant used for the secondary coagulation as described above. For example, the coagulant may include more than one of water and N-methylmorpholine-N-oxide (NMMO).

[0079] According to one embodiment, when the coagulant contains water and NMMO, the coagulant may contain 60% to 90% by weight of water and 10% to 40% by weight of NMMO, based on 100% by weight of the total weight of the coagulant. Alternatively, the coagulant may contain 70% to 80% by weight of water and 20% to 30% by weight of NMMO. The concentration of this coagulant can be controlled using a concentration control device to maintain stability during the manufacturing process.

[0080] <(c) Washing Process>

[0081] A washing process can be performed on the multifilaments obtained after the spinning solution has solidified. Through the washing process, the residual NMMO and / or other impurities in the filaments can be controlled to the desired level.

[0082] There are no particular restrictions on the washing method. For example, washing can be performed by using take-up rollers to introduce each solidified lyocell multifilament into the washing bath. Alternatively, washing can be performed by spraying washing liquid onto the multifilament as it is conveyed via the take-up rollers to the next process.

[0083] There are no particular limitations on the composition of the detergent. For example, the detergent may include water and may further include other known additives.

[0084] In addition, considering the reuse after washing, the washing liquid can be adjusted to a temperature of up to 100°C.

[0085] <(d) Emulsion Treatment Process>

[0086] After washing the multifilament yarn, an emulsion treatment process can be performed to apply an emulsion to its surface. By applying the emulsion to the multifilament yarn, friction on the filaments during the subsequent crimping process can be reduced, thus ensuring smooth crimping. The emulsion treatment process can be performed once, or more than twice as needed. If the emulsion treatment is performed more than twice, the process can be referred to in chronological order as a single emulsion treatment, a double emulsion treatment, etc.

[0087] Without particular limitations, emulsion treatment can be performed by immersing each lyocell multifilament in a bath filled with emulsion until each filament is completely submerged. Alternatively, emulsion treatment can be performed by spraying an emulsion solution onto the multifilament as it is being conveyed to the next step via take-up rollers.

[0088] Following the emulsion treatment as described above, in order to ensure that the amount of emulsion applied to each Lyocell multifilament is uniform, a further process may be performed in which rollers (etc.) positioned before and / or after the emulsion treatment extrude the emulsion from the surface of the Lyocell multifilament.

[0089] After this emulsion treatment, drying can be performed before the curling process.

[0090] <(e) Curling process>

[0091] The crimping process can be a method of obtaining crimped multifilaments, preferably crimped yarns, by applying pressure to emulsion-treated multifilaments using steam and / or pressure rollers. The crimping process can be referred to as the crimping step.

[0092] By crimping, each lyocell multifilament can be given a wave shape, and the fiber can acquire a fluffy property. Crimping can be performed using known crimping devices, including stuffer boxes and / or steam boxes.

[0093] According to one embodiment, the crimping process can be performed by first supplying steam to each lyocell multifilament to preheat and swell it, and then pressing each lyocell multifilament with pressure rollers to form crimps on the lyocell multifilament. In this case, a steam box can be used for steam supply, and such a steam box can be located upstream of the crimping device. In the crimping process, the steam supply can be omitted if necessary.

[0094] According to one embodiment, the crimping process can be performed by supplying steam while applying pressure to the lyocell multifilament with pressure rollers.

[0095] According to one embodiment, a crimping process can be performed by pressing each lyocell multifilament with a pressure roller to form crimps in each lyocell multifilament. Furthermore, steam supply may not be required before pressing, during pressing, or both before and during pressing.

[0096] According to one embodiment, in the crimping process, a doctor blade can be used to apply a predetermined pressure to each lyocell multifilament. The doctor blade helps control the residence time of the filaments loaded into the crimping machine's packing box, thereby helping to adjust the number of crimps. This doctor blade can be positioned, for example, in the travel path of each lyocell multifilament discharged from the pressing point after being pressed by the aforementioned rollers.

[0097] According to one embodiment, the curling process can be performed in a temperature range of 120°C to 250°C. If the temperature is too low, the shape stability of the curl may deteriorate; if the temperature is too high, the concentration of oil components in the packing box may increase, making curl formation difficult.

[0098] The lyocell material disclosed herein can be obtained by the above-described method for preparing lyocell materials.

[0099] The lyocell material disclosed herein can be a material that can be obtained by the above-described method for preparing lyocell materials.

[0100] [Smoking products]

[0101] The aforementioned lyocell material may be included in smoking articles. Smoking articles may be aerosol-generating articles. Aerosol-generating articles may include aerosol-generating materials or aerosol-forming matrices.

[0102] For example, lyocell materials can be included in combustible cigarettes or heat-not-burn cigarettes, and heat-not-burn cigarettes can be used with aerosol generating devices.

[0103] For example, when used as a heated non-combustible smoking article, the smoking article can be inserted separately into the aerosol generating device. Here, the aerosol generating device may include a receiving tank for accommodating the aerosol generating article, and may further include a heater for heating the aerosol generating article to generate aerosol, a controller for the overall operation of the aerosol generating device, a battery for providing power for the operation of the aerosol generating device, and a sensor for detecting that the aerosol generating article has been inserted into the aerosol generating device.

[0104] A smoking article may include a tobacco medium, a filter for the smoking article, and a wrapping paper, wherein the filter for the smoking article may be located at one end of the tobacco medium, for example, at the rear or front end. The tobacco medium and the filter for the smoking article may each include a single segment, or may independently include multiple segments.

[0105] The tobacco medium may include tobacco material, and the tobacco material may include nicotine. Additionally, the tobacco medium may further include excipients.

[0106] Excipients may include binders, fillers, and other additives. For example, the tobacco medium contained in the tobacco medium section may be manufactured in the form of particles containing tobacco materials and excipients.

[0107] For example, to maintain the consistent shape, strength, and quality of the tobacco media, additional filler material may be included. Lyocell material, for instance, may be included in the tobacco media. Additionally, lyocell material can be used as a filler.

[0108] Packaging paper can be further divided into cigarette paper for packaging the tobacco media, filter paper for wrapping the filter tip, and tipping wrapper for connecting the tobacco media and the filter tip.

[0109] [Filters for smoking products]

[0110] Lyocell material can be used in filters for smoking products. The lyocell material can be lyocell tow. In one embodiment, the lyocell tow can be crimped.

[0111] For example, this application relates to a filter tip for a smoking product. The filter tip for a smoking product may include a lyocell material, and the lyocell material may be the same as described above. Additionally, the filter tip for a smoking product may include lyocell tow, and the lyocell tow may be the same as described above.

[0112] In one embodiment, the filter tip for a smoking article may further comprise wrapping paper (which may be referred to as winding paper, filter paper, or filter wrapping paper). For example, the wrapping paper may wrap the aforementioned lyocell fiber bundle and may be a porous or non-porous paper that maintains the shape of the filter tip (e.g., cylindrical).

[0113] In one embodiment, the filter tip for a smoking product may have a predetermined shape and size.

[0114] In one embodiment, the filter tip can have a rod-like shape. For example, a filter tip for a smoking article can have a shape similar to a cylinder. Although filters for smoking articles can be manufactured in shapes other than cylindrical, a cylindrical shape is advantageous for including the largest volume of lyocell material within the filter tip space.

[0115] In one embodiment, the filter tip may have a length, for example, from 10 mm to 50 mm. For example, the lower limit of the length of the filter tip may be 15 mm or more, 20 mm or more, 25 mm or more, 30 mm or more, 35 mm or more, 40 mm or more, or 45 mm or more, and the upper limit may be less than 45 mm, less than 40 mm, less than 35 mm, less than 30 mm, less than 25 mm, less than 20 mm, or less than 15 mm.

[0116] In one embodiment, the filter tip having the above-mentioned length may have a circular cross-section, and the circumference of the circular cross-section may be from 10 mm to 40 mm. For example, the lower limit of the circumference of the filter tip may be 15 mm or more, 20 mm or more, 25 mm or more, 30 mm or more, or 35 mm or more, and the upper limit may be less than 35 mm, less than 30 mm, less than 25 mm, less than 20 mm, or less than 15 mm.

[0117] In one embodiment, a filter for a smoking article may include lyocell tow and filter wrapping paper. The description of the lyocell tow and filter wrapping paper is the same as described above and is therefore omitted.

[0118] The wrapping paper can wrap the aforementioned lyocell fiber bundles and can be porous or non-porous paper that maintains the shape of the filter tip (e.g., cylindrical).

[0119] In one implementation, when using porous packaging paper, the packaging paper can have a porosity of 10 CU to 50,000 CU (Coresta Units). A Coresta Unit can be defined as the number of centimeters of material passing through it under a pressure difference of 1 kPa. 2 The volumetric airflow velocity (cm) of the substrate sample (i.e., porous packaging paper) 3 ·min -1 ).

[0120] In one embodiment, the basis weight of the packaging paper may be 15 g / cm³. 2 Up to 60 g / cm 2 .

[0121] In one embodiment, the weight of the rod-shaped filter tip can be 50 mg or more.

[0122] The description of other smoking products using filters or materials contained therein is the same as described above, and therefore omitted.

[0123] The present disclosure is described in more detail with reference to the following preparation examples, embodiments, and comparative examples. However, the embodiments are provided merely to illustrate the present disclosure, and the scope of the disclosure is not limited thereto.

[0124] Preparation Example

[0125] A spinning solution with a concentration of 11 wt% was prepared by mixing cellulose slurry with an NMMO / H2O solvent containing 0.01 wt% propyl gallate. The viscosity, hemicellulose content, Fe content, and Si content of this cellulose slurry, measured by the CED (copper ethylenediamine diamine) solution method, are shown in Table 1 below. Next, the spinning solution was spun while maintaining a spinning temperature of 110°C at the spinning nozzle, appropriately controlling the discharge rate and spinning speed.

[0126] The spinning solution on the filament exiting the spinning nozzle passes through the air gap region and is then fed into a coagulation bath containing a coagulation solution (75 wt% water and 25 wt% NMMO at 25°C). In this process, cooling air in the air gap region provides a temperature of 8°C and 200 Nm³ / h. 3 An airflow rate of / h is used to solidify the spinning solution in one step. Additionally, sensors and refractometers are used to continuously monitor the concentration of the solidified solution.

[0127] The solidified lyocell filaments are then washed. Specifically, the filaments are fed into take-up rollers and residual NMMO is removed by a washing solution sprayed in a washing device. The washed filaments are then immersed in a bath with a predetermined emulsion concentration.

[0128] The filaments immersed in the bath are then passed through a nip roll installed at the bath outlet and fed into a crimping machine for crimping. The crimping machine is adjusted to impart an appropriate number of crimps to the filaments, and crimped filament bundles are produced through this crimping machine.

[0129] [Table 1]

[0130] [Evaluation Method]

[0131] (1) 0.5% CED (cP) - Measured according to TAPPI standard T230 om-94. Specifically, take 0.25 g of slurry sample and dissolve it in 25 mL of 0.5% CED solution, then measure it using a viscometer at 25 ± 0.1 °C. Measure the flow time and substitute it into the following formula to calculate the viscosity value.

[0132] V = C × t × d

[0133] (V: Viscosity of the solution (cPs); C: Viscometer constant; t: Flow time; d: Density of the solution)

[0134] (2) Hemicellulose content - measured according to KS M 7044:2016.

[0135] α-cellulose: a carbohydrate insoluble in 17.5% NaOH aqueous solution at 20°C.

[0136] β-cellulose: The substance precipitated during the acidification of the extracted precipitate.

[0137] γ-cellulose: A substance that dissolves in alkali and does not precipitate upon acidification.

[0138] β-cellulose and γ-cellulose are collectively referred to as "hemicellulose".

[0139] Measurement of α-cellulose content

[0140] Place 5 g of dried slurry sample in a 300 mL covered beaker and let it stand alone in a 20°C water bath for 30 minutes. Moisten the sample evenly with two 50 mL portions of 17.5% NaOH aqueous solution at 20°C and let it stand. After complete dissolution, filter the sample under reduced pressure using a pump, and wash repeatedly by adding distilled water and applying vacuum filtration. Obtain the dry weight of the residual fibers.

[0141] α-cellulose content (%) = (dry weight of residual fiber / weight of sample) × 100

[0142] Measurement of hemicellulose content

[0143] Hemicellulose content (%) = 100 - α-cellulose content (%)

[0144] (3) Fe (ppm) and Si (ppm) content by weight - Inorganic components in the slurry were measured using ICP-OES (Avio-550, from PerkinElmer).

[0145] (4) Spinning processability - Spinning performance is rated as good or poor based on the uniformity of discharge pressure, the occurrence of filament breakage in the multifilament extruded from the spinneret, and the presence of contamination on the spinneret. Ratings O, △, and X are evaluated according to the following criteria.

[0146] O: The discharge pressure is uniform, no filament breakage occurs in the spinneret, there is no contamination on the spinneret, and stable long-term production is possible.

[0147] △: The discharge pressure is uniform, but filament breakage occasionally occurs in the spinneret. During long-term production, contaminants accumulate in the spinneret.

[0148] X: Severe fluctuations in discharge pressure, or breakage of filaments in the extruded multifilaments, making production impossible.

[0149] (5) Appearance - Visually inspect the appearance of the produced samples and classify them as good or bad.

[0150] Good: The sample is nearly white.

[0151] Defective: The sample is yellowish or reddish.

[0152] (6) Monofilament Strength - The multifilament samples obtained after emulsion treatment were pre-dried at 110°C for 2 hours to reduce the moisture content to below the process moisture level, and then placed under the standard conditions of KS K 0901 for at least 24 hours to achieve moisture equilibrium. Afterward, monofilament samples were separated from the multifilament samples. The tensile strength of the separated monofilament samples was tested using a low-speed elongation tensile tester (Instron) at a tensile speed of 60 mm / min.

[0153] (7) Cigarette filter cut quality - To evaluate the quality of cut quality, cigarette rods are manufactured and their cut sections are visually observed and classified as good or bad.

[0154] Good: The cut cross-section of the filter rod is smooth.

[0155] Defects: The cut cross-section of the filter rod is not smooth, and the fibers are clumped together or protrude.

[0156] [Table 2] Evaluation results: O - Good; △ - Average; X - Poor As shown in Table 2, when the cellulose slurry has a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight, the samples exhibit good spinning processability, good appearance, and good cigarette cutting properties while providing a monofilament strength of 3 g / d to 7 g / d (sufficient for use as a filter tip in smoking products). Furthermore, through Comparative Examples 1 to 5, it was confirmed that if any one of the CED viscosity, hemicellulose content, Fe content, or Si content is not met, the lyocell material will not be suitable for manufacturing filters for smoking products.

[0157] While preferred embodiments of this disclosure have been described with reference to the accompanying drawings and examples, these are merely exemplary, and those skilled in the art will understand that various modifications and other equivalent embodiments can be made. Therefore, the scope of protection of this disclosure should be determined by the appended claims.

Claims

1. A lyocell material prepared from a stock solution, said stock solution comprising cellulose slurry and N-methylmorpholine-N-oxide (NMMO), in, The cellulose slurry has a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight.

2. The lyocell material as described in claim 1, in, The cellulose slurry has a hemicellulose content of less than 4% by weight.

3. The lyocell material as described in claim 1, in, The cellulose pulp contains 1 ppm to 20 ppm of iron (Fe) by weight.

4. The lyocell material as described in claim 1, in, The cellulose pulp contains 1 ppm to 90 ppm of silicon (Si) by weight.

5. The lyocell material as described in claim 1, in, The degree of polymerization of the cellulose slurry is between 600 and 1,700.

6. The lyocell material as described in claim 1, in, The lyocell material comprises at least one lyocell monofilament. The strength of the lyocell monofilament is 3 g / d to 8 g / d.

7. The lyocell material as described in claim 1, in, The Lyocell material is curled.

8. The lyocell material as described in claim 7, in, The Lyocell material has 10 to 50 curls per inch.

9. The lyocell material as described in claim 1, in, The lyocell material is lyocell filament bundle.

10. The lyocell material as described in claim 9, in, The lyocell bundle has an irregular cross-section.

11. The lyocell material as described in claim 9, in, The total fineness of the lyocell bundle is between 15,000 and 55,000 denier.

12. The lyocell material as described in claim 1, in, The Lyocell material is used in the filter tip of smoking products.

13. A smoking article comprising the lyocell material as described in claim 1.

14. A method for preparing a lyocell material, the method comprising: Spinning is performed on a dope solution containing cellulose slurry and N-methylmorpholine-N-oxide (NMMO) through a spinneret; The spinning solution is solidified to obtain Lyocell multifilament; The Lyocell multifilament is washed and treated with an emulsion; as well as The multifilaments treated with emulsion are crimped to obtain crimped filament bundles. The cellulose slurry has a CED viscosity of 4.0 to 11.0, a hemicellulose content of less than 5% by weight, an Fe content of at least 1 ppm and less than 30 ppm by weight, and a Si content of at least 1 ppm and less than 100 ppm by weight.

15. The method for preparing lyocell material as described in claim 14, in, The cellulose slurry has a hemicellulose content of less than 4% by weight.

16. The method for preparing lyocell material as described in claim 14, in, The cellulose slurry contains 1 ppm to 20 ppm of Fe by weight.

17. The method for preparing lyocell material as described in claim 14, in, The cellulose slurry contains 1 ppm to 90 ppm of Si by weight.

18. The method for preparing lyocell material as described in claim 14, in, The degree of polymerization of the cellulose slurry is between 600 and 1,700.

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