EP4596765A1

EP4596765A1 - Spinning dope, lyocell material, filters, smoking articles and method for preparing thereof

Info

Publication number: EP4596765A1
Application number: EP24223473.0A
Authority: EP
Inventors: Eun Young Park; Jong Cheol Jeong; Sang Woo Jin; Jeong Hun Lee; Seung Dong SEO; Yeong Nam Hwang; Ki Jin AHN; Kyeng Bae Ma; Jin Chul Yang; John Tae Lee; Min Hee Hwang
Original assignee: Kolon Industries Inc; KT&G Corp
Current assignee: Kolon Industries Inc; KT&G Corp
Priority date: 2023-12-28
Filing date: 2024-12-27
Publication date: 2025-08-06
Also published as: WO2025143824A1; KR20250103538A

Abstract

The present application relates to a lyocell material, a filter for a smoking article including the lyocell material, and a smoking article. The lyocell material and the filter for a smoking article according to the present application may replace a cellulose acetate material and a filter for a smoking article including the same in the art.

Description

Technical Field

The present application relates to a spinning dope, a lyocell material, a filter including the lyocell material, a smoking article, and a method of preparing the lyocell material.

Background Art

Until now, cellulose acetate fibers have been mainly used as tobacco filter materials. Cellulose acetate is known to be a biodegradable material, but filters for a smoking article made of cellulose acetate remain in their original form for 1 to 2 years even after being buried in soil, and a considerable amount of time is required until the filters are completely biodegraded. Considering the amount and toxicity of tobacco products that are discarded and left in the living environment as well as tobacco products that are collected as waste after being used for smoking and then buried in a landfill, there is a need to further improve the biodegradability of filters for a smoking article. Accordingly, lyocell, which is more environmentally friendly, has recently been chosen as a material for replacing cellulose acetate.

Disclosure of Invention

Technical Problem

An object of the present application is to provide a lyocell material capable of replacing cellulose acetate commercialized for a filter for a smoking article.
Another object of the present application is to provide a lyocell material for a filter for a smoking article, of which a preparation process is environmentally friendly and which has excellent biodegradability when discarded.
Another object of the present application is to provide a lyocell material capable of replacing cellulose acetate commercialized for a filter for a smoking article, and/or a spinning dope for preparing a lyocell material for a filter for a smoking article, of which a preparation process is environmentally friendly and which has excellent biodegradability when discarded.
Another object of the present application is to provide a lyocell filter for a smoking article.
Another object of the present application is to provide a smoking article (for example, a cigarette) including a lyocell filter.

Solution to Problem

According to an aspect of the present application, there may be provided a spinning dope, a lyocell material, a filter including the lyocell material, a smoking article, and the like.
The lyocell material may include one or more lyocell multifilaments.
The lyocell multifilament may include one or more lyocell monofilaments.
According to an aspect of the present application, there is provided a spinning dope including cellulose pulp and N-methylmorpholine N-oxide (NMMO) and having a complex viscosity of 10 Pa·s to 200 Pa·s.
According to another aspect of the present application, there may be provided a lyocell material including a lyocell multifilament spun by using the spinning dope.
According to another aspect of the present application, there may be provided a filter for a lyocell smoking article including the lyocell material.
According to another aspect of the present application, there may be provided a smoking article including the lyocell material or the filter.
According to another aspect of the present application, there may be provided a method of preparing the lyocell material, a filter including the same, and a smoking article.
As used herein, the term "smoking article" may refer to an article such as a tobacco (cigarette) or a cigar capable of generating aerosol. In this regard, the smoking article may include an aerosol-generating material or an aerosol-forming substrate. In addition, the smoking article may include a solid material based on a tobacco raw material such as a tobacco leaf, a cut tobacco, or a reconstituted tobacco. In addition, the smoking material may include a volatile compound.
As used herein, the term "crimp" may refer to a weaved, curled, or undulated configuration imparted to materials such as a fiber, a (mono)filament, a multifilament, and/or yarn inherently or through mechanical, thermal, and/or chemical processes. The crimp may be characterized by a periodic deviation from a straight line axis along a length of a material, a fiber, a filament, a multifilament, and/or yarn. In the material, the fiber, the filament, the multifilament, and/or the yarn, one crimp may be defined as one repeating unit of the periodic deviation. The presence of the crimp affects properties such as elasticity, bulk, resilience, and texture of a material and a fabric made of the material.
As used herein, the term "degree of polymerization (DPw)" may refer to the number of monomer units and/or repeating units in a macromolecule, a polymer, or an oligomer molecule. The DPw may be expressed as Mn/M0, wherein Mn is a number average molecular weight of a macromolecule, a polymer, or an oligomer molecule, and M0 is a molecular weight of a monomer or a repeating unit.
As used herein, the term "lyocell multifilament" may refer to a multifilament made of cellulose. In particular, the lyocell multifilament may be a (multi)filament and/or fiber made of cellulose derived or mainly derived from wood pulp. In particular, the lyocell multifilament may be a semi-synthetic (multi)filament and/or fiber.
As used herein, the term "lyocell tow" includes at least one lyocell multifilament or consists of at least one lyocell multifilament.
As used herein, the term "bloomed lyocell material" refers to a lyocell material, a lyocell fiber, and/or a lyocell multifilament that are separated, uncoiled, unspooled, loosened, or unwrapped from an original compressed and/or rolled state.
As used herein, the term "multi-lobal cross section" may refer to a cross-sectional shape that deviates from a standard circular shape. For example, a cross-sectional shape may include a Y-shaped cross section, a rectangular cross section, a star-shaped cross section, a leaf-shaped cross section, a hexagonal cross section, a polygonal cross section, and the like. The multi-lobal cross section may include three or more protrusions, for example, three protrusions. Here, the term "protrusion" may refer to a distinct and extended segment or arm extending outward from a central core or junction point of a monofilament cross section. A multi-lobal cross section including three protrusions may be referred to as a "Y-shaped cross section." Lyocell tow may have a Y-shaped cross section for use in cigarette filters.
In some embodiments, a lyocell multifilament may include one or more monofilaments, and one or more of the monofilaments may have a multi-lobal cross section.
In some embodiments, a lyocell multifilament may include one or more monofilaments, and all of the monofilaments may have a multi-lobal cross section.
As used herein, the term "tensile strength" refers to the maximum tensile force or tension that a filament or fiber may withstand before breaking. The tensile strength is used to measure the mechanical strength of a filament or fiber and is an important parameter for determining durability and reliability. Tensile strength is measured as force per unit area.
As used herein, the term "viscosity" or "complex viscosity" refers to dynamic resistance of a fluid to a change in shape or to movement of neighboring portions relative to one another. Viscosity or complex viscosity is defined as a force multiplied by a time divided by an area. Therefore, the SI unit of the viscosity are N·s/m² or Pa·s. Viscosity may be measured by using various types of viscometers and rheometers. Complex viscosity is a ratio of stress to oscillatory shear stress and is typically measured by using a rheometer.
As used herein, the term "breaking elongation" of a fiber or filament refers to an elongation expressed as a percentage (%) of a length of a fiber or filament increased until the fiber or filament breaks to the original length of the fiber. A ratio is obtained by dividing a difference between a final length of a cut fiber or filament and an original length by the original length, and the ratio is multiplied by 100 to calculate an elongation (%). In general, an elongation of a filament partially reflects a degree of ease by which the filament is stretched. It is known that filaments with a high breaking elongation with respect to breaking strength may be easily stretched even under small loads.
As used herein, the term "draft ratio" refers to an elongation ratio of a spun dope stretched until the spun dope is wound and is expressed as a ratio V_s/V₀ of a winding speed V_s to a discharge linear speed V₀ of a dope spun from a spinneret. In this case, the discharge linear speed V₀ is a speed of the dope spun from a discharge port of a spinneret (unit: length of discharged dope per unit time (for example, unit: m/min)), and the winding speed V_s is a speed at which a fiber or filament formed from the spun dope is wound (for example, unit: m/min).
As used herein, the term "basis weight" refers to mass per unit area of wrapping paper and/or wrapper. The basis weight of wrapping paper and/or wrapper may be determined by measuring the mass and area of the wrapping paper and/or wrapper and dividing the mass of the wrapping paper and/or wrapper by the area.
Unless specifically defined otherwise in the specification, when the properties of lyocell materials, filters for a smoking article, and components or compositions related thereto are affected by a temperature, the temperature at which the properties are confirmed or measured may be room temperature. In this case, the room temperature may be a temperature which is not particularly lowered or raised and may be, for example, in a range of 10°C to 35 °C, in particular, in a range of 15°C to 35 °C or 20 °C to 30 °C, or may be 25 °C.
Hereinafter, the present application is described in more detail.
The present application relates to a lyocell material. The lyocell material may be used in a smoking article, and although not particularly limited, the lyocell material may be used in a filter for a smoking article.
According to an aspect of the present application, there is provided a spinning dope including cellulose pulp and NMMO and having a complex viscosity of 10 Pa·s to 200 Pa·s.
In some embodiments, in the spinning dope, the cellulose pulp may include alpha-cellulose, and a content of the alpha-cellulose may be 85 wt% or more with respect to 100 wt% of the cellulose pulp.
In some embodiments, in the spinning dope, the cellulose pulp may further include hemicellulose, and a content of the hemicellulose may be less than 15 wt% with respect to 100 wt% of the cellulose pulp.
In some embodiments, a DPw of the cellulose pulp in the spinning dope may be in a range of 600 to 1,700. In some embodiments, the DPw refers to the number of repeating units and/or monomers of the cellulose, alpha-cellulose, and/or hemicellulose in the cellulose pulp.
In some embodiments, in the spinning dope, the spinning dope may further include water, and a content of water may be in a range of 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of the total weight of NMMO and water.
In some embodiments, in the spinning dope, complex viscosity may be measured by vibrating the spinning dope at a frequency of 20 rad/s.
In some embodiments, in the spinning dope, the complex viscosity may be measured by using a rotational rheometer.
In some embodiments, in the spinning dope, the complex viscosity may be measured at a temperature of 110 °C to 120 °C.
In addition, according to another aspect of the present application, there is provided a lyocell material including a lyocell multifilament spun by using any one of the above-described spinning dopes.
In some embodiments, in the lyocell material, the lyocell multifilament may be imparted with crimps. A crimp may be provided in crimp providing of a method of preparing a lyocell material, which will be described below.
In some embodiments, in the lyocell material, the lyocell multifilament may include one or more monofilaments, and one or more of the monofilaments may have a multi-lobal cross section.
In some embodiments, in the lyocell material, the monofilaments may not have a circular cross section. For example, all of the monofilaments may not have a circular cross section.
In some embodiments, in the lyocell material, the number of crimps of the lyocell material may be in a range of 3.94 ea/cm to 23.62 ea/cm (10 ea/inch to 60 ea/inch).
In some embodiments, in the lyocell material, the number of crimps of the lyocell material may be in a range of 9.84 ea/cm to 19.69 ea/cm (25 ea/inch to 50 ea/inch).
In some embodiments, in the lyocell material, tensile strength of the monofilament may be in a range of 0.132 N/tex to 0.618 N/tex (1.5 gf/d to 7.0 gf/d).
In some embodiments, in the lyocell material, the tensile strength of the monofilament may be in a range of 0.265 N/tex to 0.530 N/tex (3.0 gf/d to 6.0 gf/d).
In some embodiments, in the lyocell material, a breaking elongation of the monofilament may be in a range of 2.0 % to 10.0 %.
In some embodiments, in the lyocell material, the breaking elongation of the monofilament may be in a range of 3.5 % to 7.5%.
In some embodiments, in the lyocell material, a single fineness of the lyocell multifilament may be in a range of 1.67 dtex to 9.44 dtex (1.5 denier to 8.5 denier).
In some embodiments, the lyocell material may have a total fineness of 1,667 tex to 6,111 tex (15,000 denier to 55,000 denier).
In some embodiments, the lyocell material may be lyocell tow.
In some embodiments, the lyocell material may be used for a filter for a smoking article.
In addition, according to another aspect of the present application, there is provided a filter for a smoking article including any one of the above-described lyocell materials.
In addition, according to another aspect of the present application, there is provided a smoking article including any one of the above-described filters for a smoking article.
In addition, according to another aspect of the present application, there is provided a method of preparing a lyocell material, the method including lyocell dope spinning, coagulation and lyocell multifilament obtainment, washing, emulsion treatment, and crimp providing.
In some embodiments, in the method of preparing a lyocell material, the lyocell dope spinning may be performed by using a spinning dope including cellulose pulp and NMMO, and the spinning dope may have a complex viscosity of 10 Pa·s to 200 Pa·s.
In some embodiments, in the method of preparing a lyocell material, the cellulose pulp may include alpha-cellulose, and a content of the alpha-cellulose may be 85 wt% or more with respect to 100 wt% of the cellulose pulp.
In some embodiments, in the method of preparing a lyocell material, the cellulose pulp may further include hemicellulose, and a content of the hemicellulose may be less than 15 wt% with respect to 100 wt% of the cellulose pulp.
In some embodiments, in the method of preparing a lyocell material, a DPw of the cellulose pulp may be in a range of 600 to 1,700. In some embodiments, the DPw refers to the number of repeating units and/or monomers of the cellulose, alpha-cellulose, and/or hemicellulose in the cellulose pulp.
In some embodiments, in the method of preparing a lyocell material, the spinning dope further includes water, and a content of water may be in a range of 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of the total weight of NMMO and water.
In some embodiments, in the method of preparing a lyocell material, the complex viscosity may be measured by vibrating the spinning dope at a frequency of 20 rad/s.
In some embodiments, in the method of preparing a lyocell material, the spinning dope may be spun through a spinneret, the spinneret may include one or more discharge ports, and an area of the discharge port may be in a range of 0.01 mm² to 0.1 mm².
In some embodiments, in the method of preparing a lyocell material, a spinning speed of the lyocell dope spinning may be in a range of 50 m/min to 500 m/min.
In some embodiments, in the method of preparing a lyocell material, a draft ratio of the lyocell dope spinning may be in a range of 2.5 to 28.
In some embodiments, the spinning dope has a complex viscosity of 10 Pa·s to 200 Pa·s. In some embodiments, a lower limit of the complex viscosity may be 10 Pa·s, 15 Pa·s, 20 Pa·s, 25 Pa·s, 30 Pa·s, 35 Pa·s, 40 Pa·s, 45 Pa·s, 50 Pa·s, 55 Pa·s, 60 Pa·s, 65 Pa·s, 70 Pa·s, 75 Pa·s, 80 Pa·s, 85 Pa·s, 90 Pa·s, 95 Pa·s, 100 Pa·s, 105 Pa·s, 110 Pa·s, 115 Pa·s, 120 Pa·s, 125 Pa·s, 130 Pa·s, 135 Pa·s, 140 Pa·s, 150 Pa·s, 155 Pa·s, 160 Pa·s, 165 Pa·s, 170 Pa·s, 175 Pa·s, 180 Pa·s, 185 Pa·s, 190 Pa·s, or 195 Pa·s. In addition, in some embodiments, an upper limit of the complex viscosity may be 200 Pa·s, 195 Pa·s, 190 Pa·s, 185 Pa·s, 180 Pa·s, 175 Pa·s, 170 Pa·s, 165 Pa·s, 160 Pa·s, 155 Pa·s, 150 Pa·s, 145 Pa·s, 140 Pa·s, 135 Pa·s, 130 Pa·s, 125 Pa·s, 120 Pa·s, 115 Pa·s, 110 Pa·s, 105 Pa·s, 100 Pa·s, 95 Pa·s, 90 Pa·s, 85 Pa·s, 80 Pa·s, 75 Pa·s, 70 Pa·s, 65 Pa·s, 60 Pa·s, 55 Pa·s, 50 Pa·s, 45 Pa·s, 40 Pa·s, 35 Pa·s, 30 Pa·s, 25 Pa·s, 20 Pa·s, or 15 Pa·s.
In some embodiments, the complex viscosity of the spinning dope may be in a range of 10 Pa·s to 200 Pa·s,10 Pa·s to 190 Pa·s, 10 Pa·s to 180 Pa·s, 10 Pa·s to 170 Pa·s, 10 Pa·s to 160 Pa·s, 10 Pa·s to 150 Pa·s, 10 Pa·s to 140 Pa·s, 10 Pa·s to 130 Pa·s, 10 Pa·s to 120 Pa·s, 10 Pa·s to 110 Pa·s, 10 Pa·s to 100 Pa·s, 10 Pa·s to 90 Pa·s, 10 Pa·s to 80 Pa·s, 10 Pa·s to 70 Pa·s, 10 Pa·s to 60 Pa·s, 10 Pa·s to 50 Pa·s, 10 Pa·s to 40 Pa·s, 10 Pa·s to 30 Pa·s, 10 Pa·s to 20 Pa·s, 20 Pa·s to 200 Pa·s, 20 Pa·s to 190 Pa·s, 20 Pa·s to 180 Pa·s, 20 Pa·s to 170 Pa·s, 20 Pa·s to 160 Pa·s, 20 Pa·s to 150 Pa·s, 20 Pa·s to 140 Pa·s, 20 Pa·s to 130 Pa·s, 20 Pa·s to 120 Pa·s, 20 Pa·s to 110 Pa·s, 20 Pa·s to 100 Pa·s, 20 Pa·s to 90 Pa·s, 20 Pa·s to 80 Pa·s, 20 Pa·s to 70 Pa·s, 20 Pa·s to 60 Pa·s, 20 Pa·s to 50 Pa·s, 20 Pa·s to 40 Pa·s, 20 Pa·s to 30 Pa·s, 30 Pa·s to 200 Pa·s, 30 Pa·s to 190 Pa·s, 30 Pa·s to 180 Pa·s, 30 Pa·s to 170 Pa·s, 30 Pa·s to 160 Pa·s, 30 Pa·s to 150 Pa·s, 30 Pa·s to 140 Pa·s, 30 Pa·s to 130 Pa·s, 30 Pa·s to 120 Pa·s, 30 Pa·s to 110 Pa·s, 30 Pa·s to 100 Pa·s, 30 Pa·s to 90 Pa·s, 30 Pa·s to 80 Pa·s, 30 Pa·s to 70 Pa·s, 30 Pa·s to 60 Pa·s, 30 Pa·s to 50 Pa·s, 30 Pa·s to 40 Pa·s, 40 Pa·s to 200 Pa·s, 40 Pa·s to 190 Pa·s, 40 Pa·s to 180 Pa·s, 40 Pa·s to 170 Pa·s, 40 Pa·s to 160 Pa·s, 40 Pa·s to 150 Pa·s, 40 Pa·s to 140 Pa·s, 40 Pa·s to 130 Pa·s, 40 Pa·s to 120 Pa·s, 40 Pa·s to 110 Pa·s, 40 Pa·s to 100 Pa·s, 40 Pa·s to 90 Pa·s, 40 Pa·s to 80 Pa·s, 40 Pa·s to 70 Pa·s, 40 Pa·s to 60 Pa·s, 40 Pa·s to 50 Pa·s, 50 Pa·s to 200 Pa·s, 50 Pa·s to 190 Pa·s, 50 Pa·s to 180 Pa·s, 50 Pa·s to 170 Pa·s, 50 Pa·s to 160 Pa·s, 50 Pa·s to 150 Pa·s, 50 Pa·s to 140 Pa·s, 50 Pa·s to 130 Pa·s, 50 Pa·s to 120 Pa·s, 50 Pa·s to 110 Pa·s, 50 Pa·s to 100 Pa·s, 50 Pa·s to 90 Pa·s, 50 Pa·s to 80 Pa·s, 50 Pa·s to 70 Pa·s, 50 Pa·s to 60 Pa·s, 60 Pa·s to 200 Pa·s, 60 Pa·s to 190 Pa·s, 60 Pa·s to 180 Pa·s, 60 Pa·s to 170 Pa·s, 60 Pa·s to 160 Pa·s, 60 Pa·s to 150 Pa·s, 60 Pa·s to 140 Pa·s, 60 Pa·s to 130 Pa·s, 60 Pa·s to 120 Pa·s, 60 Pa·s to 110 Pa·s, 60 Pa·s to 100 Pa·s, 60 Pa·s to 90 Pa·s, 60 Pa·s to 80 Pa·s, 60 Pa·s to 70 Pa·s, 70 Pa·s to 200 Pa·s, 70 Pa·s to 190 Pa·s, 70 Pa·s to 180 Pa·s, 70 Pa·s to 170 Pa·s, 70 Pa·s to 160 Pa·s, 70 Pa·s to 150 Pa·s, 70 Pa·s to 140 Pa·s, 70 Pa·s to 130 Pa·s, 70 Pa·s to 120 Pa·s, 70 Pa·s to 110 Pa·s, 70 Pa·s to 100 Pa·s, 70 Pa·s to 90 Pa·s, 70 Pa·s to 80 Pa·s, 80 Pa·s to 200 Pa·s, 80 Pa·s to 190 Pa·s, 80 Pa·s to 180 Pa·s, 80 Pa·s to 170 Pa·s, 80 Pa·s to 160 Pa·s, 80 Pa·s to 150 Pa·s, 80 Pa·s to 140 Pa·s, 80 Pa·s to 130 Pa·s, 80 Pa·s to 120 Pa·s, 80 Pa·s to 110 Pa·s, 80 Pa·s to 100 Pa·s, 80 Pa·s to 90 Pa·s, 90 Pa·s to 200 Pa·s, 90 Pa·s to 190 Pa·s, 90 Pa·s to 180 Pa·s, 90 Pa·s to 170 Pa·s, 90 Pa·s to 160 Pa·s, 90 Pa·s to 150 Pa·s, 90 Pa·s to 140 Pa·s, 90 Pa·s to 130 Pa·s, 90 Pa·s to 120 Pa·s, 90 Pa·s to 110 Pa·s, 90 Pa·s to 100 Pa·s, 100 Pa·s to 200 Pa·s, 100 Pa·s to 190 Pa·s, 100 Pa·s to 180 Pa·s, 100 Pa·s to 170 Pa·s, 100 Pa·s to 160 Pa·s, 100 Pa·s to 150 Pa·s, 100 Pa·s to 140 Pa·s, 100 Pa·s to 130 Pa·s, 100 Pa·s to 120 Pa·s, 100 Pa·s to 110 Pa·s, 110 Pa·s to 200 Pa·s, 110 Pa·s to 190 Pa·s, 110 Pa·s to 180 Pa·s, 110 Pa·s to 170 Pa·s, 110 Pa·s to 160 Pa·s, 110 Pa·s to 150 Pa·s, 110 Pa·s to 140 Pa·s, 110 Pa·s to 130 Pa·s, 110 Pa·s to 120 Pa·s, 120 Pa·s to 200 Pa·s, 120 Pa·s to 190 Pa·s, 120 Pa·s to 180 Pa·s, 120 Pa·s to 170 Pa·s, 120 Pa·s to 160 Pa·s, 120 Pa·s to 150 Pa·s, 120 Pa·s to 140 Pa·s, 120 Pa·s to 130 Pa·s, 130 Pa·s to 200 Pa·s, 130 Pa·s to 190 Pa·s, 130 Pa·s to 180 Pa·s, 130 Pa·s to 170 Pa·s, 130 Pa·s to 160 Pa·s, 130 Pa·s to 150 Pa·s, 130 Pa·s to 140 Pa·s, 140 Pa·s to 200 Pa·s, 140 Pa·s to 190 Pa·s, 140 Pa·s to 180 Pa·s, 140 Pa·s to 170 Pa·s, 140 Pa·s to 160 Pa·s, 140 Pa·s to 150 Pa·s, 150 Pa·s to 200 Pa·s, 150 Pa·s to 190 Pa·s, 150 Pa·s to 180 Pa·s, 150 Pa·s to 170 Pa·s, 150 Pa·s to 160 Pa·s, 160 Pa·s to 200 Pa·s, 160 Pa·s to 190 Pa·s, 160 Pa·s to 180 Pa·s, 160 Pa·s to 170 Pa·s, 170 Pa·s to 200 Pa·s, 170 Pa·s to 190 Pa·s, 170 Pa·s to 180 Pa·s, 180 Pa·s to 200 Pa·s, 180 Pa·s to 190 Pa·s, or 190 Pa·s to 200 Pa·s.
The complex viscosity of the spinning dope may be adjusted within the above-described range, and thus the spinning dope may have physical properties desirable in preparing a lyocell multifilament. In particular, since the complex viscosity satisfies the above-described range, a monofilament prepared from the spinning dope may have good orientation. As a result, entanglement between monofilaments may be suppressed during spinning, and uniform spinning of the monofilaments may be continuously performed. In addition, since entanglement between monofilaments is suppressed, a lyocell multifilament including the monofilament may be expected to have uniform physical properties in a width direction and a length direction.
On the other hand, when the spinning dope has a complex viscosity of less than 10 Pa·s, the spinning dope may have flowability that is unsuitable for spinning. As a result, the orientation of the monofilament may not be uniform, and the breakage of the monofilament may occur.
In particular, when the spinning dope has a complex viscosity of less than 10 Pa·s, a weak thread or a flying thread may be prepared from the spinning dope. The weak thread refers to a filament of which mechanical properties are deteriorated due to insufficient strength and/or elongation. The flying thread refers to a filament that, when discharged from a spinneret, may break or fly without being put into a coagulating tank.
In some examples, when a weak thread is generated in a content of 5 wt% or more in one spinneret, spinnability is evaluated to be poor.
In addition, when the spinning dope has a complex viscosity exceeding 200 Pa·s, strong viscosity may limit the preparation of monofilaments having a small fineness. Furthermore, a discharge port included in a spinneret may be closed by the spinning dope. As a result, continuous preparation of a lyocell material may be fundamentally impossible.
In particular, when the spinning dope has a complex viscosity exceeding 200 Pa·s, the spinning dope may not be smoothly discharged from a discharge port and may be discharged in the form of a drip from the discharge port. As a result, the preparation of a filament from the spinning dope may be limited.
In some embodiments, when a drip is generated in a content of 5 wt% or more in one spinneret, spinnability is evaluated to be poor.
Meanwhile, by using a spinning dope that satisfies certain complex viscosity, a range of a draft ratio in spinning may be further widened. In particular, the draft ratio may be in a range of 2.5 to 28. Since the range of the draft ratio is widened, the properties of a monofilament prepared from the spinning dope may be adjusted in a wider range. In particular, by using the spinning dope, a fineness of a monofilament may be adjusted in a wider range. For example, through the spinning dope, a single fineness of a lyocell material may be implemented at 2.22 dtex (2.0 d) or less.
In addition, a monofilament prepared from the spinning dope may have good orientation, thereby providing a lyocell material having a small single fineness as well as increased tensile strength and/or breaking elongation.
In addition, since the lyocell material satisfies a small single fineness, increased tensile strength, and/or an increased breaking elongation as described above, a filter for a smoking article including the same may provide an increased specific surface area and increased mechanical properties. As a result, a smoking article including the filter for a smoking article may provide a user with high quality in use and may provide improved filtering performance.

[Multi-lobal cross section]

One or more of lyocell monofilaments included in a lyocell material of the present application may have a multi-lobal cross section. The term "multi-lobal" may mean that a shape of an outline of a cross section is not circular, and the term "cross section" may be a cross section obtained by cutting a lyocell monofilament in a direction virtually or actually perpendicular to a longitudinal direction of a filament.
An outline of the multi-lobal cross section may touch each of a virtual first circle and a virtual second circle. In addition, the virtual second circle may be depicted inside the virtual first circle, and/or the virtual second circle may be placed inside the virtual first circle. The "virtual first circle" may also be referred to as a "virtual circumscribed circle" and/or a "circumscribed circle," and/or the "virtual second circle" may also be referred to as a "virtual inscribed circle" and/or a "inscribed circle."
The virtual first circle may be a circle with the smallest area value among circles drawn to completely encompass one cross section of a monofilament. The virtual second circle may be a circle with the largest area value among circles drawn inside a cross section of a monofilament.
When a circumscribed circle encompassing a across section of a monofilament may be drawn, the virtual first circle may be the circumscribed circle. When an inscribed circle may be drawn inside a cross section of a monofilament, the virtual second circle may be the inscribed circle.
The multi-lobal cross section may have a shape including a plurality of protrusions and may be, for example, a Y-shaped cross section including three protrusions. It may be understood that the plurality of protrusions are formed as an integral type with the virtual second circle as a central portion and have a shape of which an end touches the virtual first circle. The terms described herein have the same meanings as described above.
A modified ratio of a monofilament may be defined by Equation 1 below. $Modified ratio = r 1 / r 2$
Here, r1 is a radius of the virtual first circle, and r2 is a radius of the virtual second circle.
For example, the radius of the virtual first circle may be in a range of 4 µm to 40 µm, the radius of the virtual second circle may be in a range of 2 µm to 14 µm, and the modified ratio may be in a range of 1.01 to 10.
In addition, a space occupancy ratio of a monofilament may be defined by Equation 2. $Space occupancy ratio = (S 1 / S 2) \times 100 (%)$
Here, S1 is an area of the virtual first circle, and S2 is a cross-sectional area of a monofilament included in a lyocell fiber.
For example, a space occupancy ratio of a monofilament having a multi-lobal cross section may be in a range of about 120 % to about 600 %.
In some embodiments, in a lyocell material, a lyocell multifilament may include one or more monofilaments, and one or more of the monofilaments may have a multi-lobal cross section.
In some embodiments, in the lyocell material, the monofilaments may not have a circular cross section. In some embodiments, all of the monofilaments may not have a circular cross section. In some embodiments, all of the monofilaments may have a circular cross section.

[Fineness]

A lyocell material of the present application may include a lyocell multifilament, and the lyocell multifilament may have a fineness suitable for preparing a filter for a smoking article and securing a function thereof.
For example, a single fineness of a filament constituting the lyocell multifilament may be in a range of 1.67 dtex to 9.44 dtex (1.5 denier to 8.5 denier). In this case, a single fineness of a filament may refer to a fineness of a single monofilament separated from a multifilament.
In particular, the single fineness of the filament may be 8.89 dtex (8.0 denier) or less, 7.78 dtex (7.0 denier) or less, 7.22 dtex (6.5 denier) or less, 6.67 dtex (6.0 denier) or less, 6.11 dtex (5.5 denier) or less, 5.56 dtex (5.0 denier) or less, 5.00 dtex (4.5 denier) or less, 3.89 dtex (3.5 denier) or less, 3.33 dtex (3.0 denier) or less, 2.78 dtex (2.5 denier) or less, or 2.22 dtex (2.0 denier) or less. A lower limit of the single fineness of the filament may be, in particular, 2.22 dtex (2.0 denier) or more, 2.78 dtex (2.5 denier) or more, 3.33 dtex (3.0 denier) or more, 3.89 dtex (3.5 denier) or more, 4.44 dtex (4.0 denier) or more, 5.00 dtex (4.5 denier) or more, 5.56 dtex (5.0 denier) or more, 6.11 dtex (5.5 denier) or more, 6.67 dtex (6.0 denier) or more, 7.22 dtex (6.5 denier) or more, or 7.78 dtex (7.0 denier) or more. Satisfying the above range may be more advantageous in securing stable physical properties (for example, implementing hardness or draw resistance) and processability of a filter for a smoking article.
In an example, the lyocell multifilament may have a total fineness of 1,667 to 6,111 tex (15,000 to 55,000 denier). For example, a lower limit of the total fineness may be, for example, 1,778 tex (16,000 denier) or more, 1,833 tex (16,500 denier) or more, 1,889 tex (17,000 denier) or more, 1,944 tex (17,500 denier) or more, 2,000 tex (18,000 denier) or more, 2,056 tex (18,500 denier) or more, 2,111 tex (19,000 denier) or more, 2,167 tex (19,500 denier) or more, 2,222 tex (20,000 denier) or more, 2,278 tex (20,500 denier) or more, 2,333 tex (21,000 denier) or more, 2,389 tex (21,500 denier) or more, 2,444 tex (22,000 denier) or more, 2,500 tex (22,500 denier) or more, 2,556 tex (23,000 denier) or more, 2,611 tex (23,500 denier) or more, 2,667 tex (24,000 denier) or more, 2,722 tex (24,500 denier) or more, 2,778 tex (25,000 denier) or more, 2,833 tex (25,500 denier) or more, 2,889 tex (26,000 denier) or more, 2,944 tex (26,500 denier) or more, 3,000 tex (27,000 denier) or more, 3,056 tex (27,500 denier) or more, 3,111 tex (28,000 denier) or more, 3,167 tex (28,500 denier) or more, 3,222 tex (29,000 denier) or more, 3,287 tex (29,500 denier) or more, 3,333 tex (30,000 denier) or more, 3,389 tex (30,500 denier) or more, 3,444 tex (31,000 denier) or more, 3,500 tex (31,500 denier) or more, 3,556 tex (32,000 denier) or more, 3,611 tex (32,500 denier) or more, 3,667 tex (33,000 denier) or more, 3,722 tex (33,500 denier) or more, 3,778 tex (34,000 denier) or more, 3,833 tex (34,500 denier) or more, 3,889 tex (35,000 denier) or more, 3,944 tex (35,500 denier) or more, 4,000 tex (36,000 denier) or more, 4,056 tex (36,500 denier) or more, 4,111 tex (37,000 denier) or more, 4,167 tex (37,500 denier) or more, 4,222 tex (38,000 denier) or more, 4,278 tex (38,500 denier) or more, 4,333 tex (39,000 denier) or more, 4,389 tex (39,500 denier) or more, 4,444 tex (40,000 denier) or more, 4,500 tex (40,500 denier) or more, 4,556 tex (41,000 denier) or more, 4,611 tex (41,500 denier) or more, 4,667 tex (42,000 denier) or more, 4,722 tex (42,500 denier) or more, 4,778 tex (43,000 denier) or more, 4,833 tex (43,500 denier) or more, 4,889 tex (44,000 denier) or more, 4,944 tex (44,500 denier) or more, 5,000 tex (45,000 denier) or more, 5,056 tex (45,500 denier) or more, 5,111 tex (46,000 denier) or more, 5,167 tex (46,500 denier) or more, 5,222 tex (47,000 denier) or more, 5,278 tex (47,500 denier) or more, 5,333 tex (48,000 denier) or more, 5,389 tex (48,500 denier) or more, 5,444 tex (49,000 denier) or more, 5,500 tex (49,500 denier) or more, 5,556 tex (50,000 denier) or more, 5,611 tex (50,500 denier) or more, 5,667 tex (51,000 denier) or more, 5,722 tex (51,500 denier) or more, 5,778 tex (52,000 denier) or more, 5,833 tex (52,500 denier) or more, 5,889 tex (53,000 denier) or more, 5,944 tex (53,500 denier) or more, 6,000 tex (54,000 denier) or more, or 6,056 tex (54,500 denier) or more. An upper limit of the total fineness may be, in particular, 6,056 tex (54,500 denier) or less, 6,000 tex (54,000 denier) or less, 5,944 tex (53,500 denier) or less, 5,889 tex (53,000 denier) or less, 5,833 tex (52,500 denier) or less, 5,778 tex (52,000 denier) or less, 5,722 tex (51,500 denier) or less, 5,667 tex (51,000 denier) or less, 5,611 tex (50,500 denier) or less, 5,556 tex (50,000 denier) or less, 5,500 tex (49,500 denier) or less, 5,444 tex (49,000 denier) or less, 5,389 tex (48,500 denier) or less, 5,333 tex (48,000 denier) or less, 5,278 tex (47,500 denier) or less, 5,222 tex (47,000 denier) or less, 5,167 tex (46,500 denier) or less, 5,111 tex (46,000 denier) or less, 5,056 tex (45,500 denier) or less, 5,000 tex (45,000 denier) or less, 4,944 tex (44,500 denier) or less, 4,889 tex (44,000 denier) or less, 4,833 tex (43,500 denier) or less, 4,778 tex (43,000 denier) or less, 4,722 tex (42,500 denier) or less, 4,667 tex (42,000 denier) or less, 4,611 tex (41,500 denier) or less, 4,556 tex (41,000 denier) or less, 4,500 tex (40,500 denier) or less, 4,444 tex (40,000 denier) or less, 4,389 tex (39,500 denier) or less, 4,333 tex (39,000 denier) or less, 4,278 tex (38,500 denier) or less, 4,222 tex (38,000 denier) or less, 4,167 tex (37,500 denier) or less, 4,111 tex (37,000 denier) or less, 4,056 tex (36,500 denier) or less, 4,000 tex (36,000 denier) or less, 3,944 tex (35,500 denier) or less, 3,889 tex (35,000 denier) or less, 3,833 tex (34,500 denier) or less, 3,778 tex (34,000 denier) or less, 3,722 tex (33,500 denier) or less, 3,667 tex (33,000 denier) or less, 3,611 tex (32,500 denier) or less, 3,556 tex (32,000 denier) or less, 3,500 tex (31,500 denier) or less, 3,444 tex (31,000 denier) or less, 3,389 tex (30,500 denier) or less, 3,333 tex (30,000 denier) or less, 3,278 tex (29,500 denier) or less, 3,222 tex (29,000 denier) or less, 3,167 tex (28,500 denier) or less, 3,111 tex (28,000 denier) or less, 3,056 tex (27,500 denier) or less, 3,000 tex (27,000 denier) or less, 2,944 tex (26,500 denier) or less, 2,889 tex (26,000 denier) or less, 2,833 tex (25,500 denier) or less, 2,778 tex (25,000 denier) or less, 2,722 tex (24,500 denier) or less, 2,667 tex (24,000 denier) or less, 2,611 tex (23,500 denier) or less, 2,556 tex (23,000 denier) or less, 2,500 tex (22,500 denier) or less, 2,444 tex (22,000 denier) or less, 2,389 tex (21,500 denier) or less, 2,333 tex (21,000 denier) or less, 2,278 tex (20,500 denier) or less, 2,222 tex (20,000 denier) or less, 2,167 tex (19,500 denier) or less, 2,111 tex (19,000 denier) or less, 2,056 tex (18,500 denier) or less, 2,000 tex (18,000 denier) or less, 1,944 tex (17,500 denier) or less, 1,889 tex (17,000 denier) or less, 1,833 tex (16,500 denier) or less, 1,778 tex (16,000 denier) or less, or 1,722 tex (15,500 denier) or less. When the total fineness is out of the above range, the preparation processability of a filter for a smoking article may not be good (continuous process is not possible due to cutting), and when an amount of tow filling filter paper during preparation of a filter for a smoking article is too small or too large, it may be difficult to secure sufficient filter physical properties (for example, hardness or draw resistance).
A method of measuring a fineness is not particularly limited, but for example, a lyocell material to be measured, for example, a 2 m sample of lyocell tow, is taken, left, and stabilized in a room with a constant temperature and humidity at a temperature of 20 °C and a humidity of 65 % for 24 hours. One end of the stabilized lyocell tow is fixed, and a 2 kg weight is attached to the other end thereof. The tow stretched due to a load thereof is maintained (stabilized) for 5 seconds and then cut into 90 cm length to obtain a sample and measure a weight of the sample (total fineness). A fineness is converted to a denier scale and calculated as a measured weight×10,000 according to a denier conversion method. A single fineness of a monofilament in the sample is calculated by dividing the total fineness of the sample by the number of strands of monofilaments in the sample.
A total fineness of the lyocell multifilament may be determined according to the single fineness of the monofilament and the number of crimps. In the present application, a single fineness and the number of crimps may be controlled, and the total fineness of tow suitable for preparing a filter for a smoking article and securing a function thereof may be secured.

[Number of crimps]

In an example, a lyocell multifilament may have 3.94 to 19.69 crimps per centimeter (10 to 50 crimps per inch). For example, the number of the crimps may be 5.91 ea/cm (15 ea/inch) or more, 7.87 ea/cm (20 ea/inch) or more, 9.84 ea/cm (25 ea/inch) or more, 11.81 ea/cm (30 ea/inch) or more, 13.78 ea/cm (35 ea/inch) or more, 15.75 ea/cm (40 ea/inch) or more, or 17.72 ea/cm (45 ea/inch) or more, and an upper limit thereof may be, for example, 17.72 ea/cm (45 ea/inch) or less, 15.75 ea/cm (40 ea/inch) or less, 13.78 ea/cm (35 ea/inch) or less, 11.81 ea/cm (30 ea/inch) or less, or 9.84 ea/cm (25 ea/inch) or less. The number of crimps and the uniformity thereof may be controlled through pressure and temperature conditions or the like related to crimping which will be described below.
Although not particularly limited, the number of crimps may be measured by using, for example, a single fiber property evaluation device (for example, Favimat). In particular, a sample of a prepared lyocell material (for example, lyocell tow) may be left and stabilized for 24 hours under conditions of a temperature of 20±2 °C and a humidity of 65±4 %. A specimen may be taken from the stabilized sample such that the crimp is not damaged. The taken specimen may be mounted on a dedicated jig with a length (gauge length) of 10 mm to 30 mm. An initial load during measurement may be 0.05 g/d, and crimp sensitivity may be 0.01 mm. The number of crimps may be measured under the above-described conditions (that is, a temperature of 20±2 °C and a humidity of 65±4 %).
Although not particularly limited, a lyocell material prepared to satisfy the single fineness, the total fineness, and/or the number of crimps described above may be used in a smoking article.

[Tensile strength]

In some embodiments, in a lyocell material, tensile strength of a monofilament may be in a range of 0.177 N/tex to 0.706 N/tex (2.0 gf/d to 8.0 gf/d). For example, an upper limit of the tensile strength of the monofilament may be 0.662 N/tex (7.5 gf/d), 0.618 N/tex (7.0 gf/d), 0.574 N/tex (6.5 gf/d), 0.530 N/tex (6.0 gf/d), 0.485 N/tex (5.5 gf/d), 0.441 N/tex (5.0 gf/d), 0.397 N/tex (4.5 gf/d), 0.353 N/tex (4.0 gf/d), 0.309 N/tex (3.5 gf/d), 0.265 N/tex (3.0 gf/d), 0.221 N/tex (2.5 gf/d), or 0.177 N/tex (2.0 gf/d), and a lower limit of the tensile strength of the monofilament may be 0.221 N/tex (2.5 gf/d), 0.265 N/tex (3.0 gf/d), 0.309 N/tex (3.5 gf/d), 0.353 N/tex (4.0 gf/d), 0.397 N/tex (4.5 gf/d), 0.441 N/tex (5.0 gf/d), 0.485 N/tex (5.5 gf/d), 0.530 N/tex (6.0 gf/d), 0.574 N/tex (6.5gf/d), 0.618 N/tex (7.0gf/d), or 0.662 N/tex (7.5 gf/d).
Tensile strength of the lyocell material may be measured through a tensile tester. Although not particularly limited, a low-speed extension type tensile tester (for example, a low-speed extension type tensile tester manufactured by Instron) may be considered as a tensile tester. For evaluation of tensile strength, a sample (for example, a monofilament) may be taken from the lyocell material. The sample may be stretched at a constant tension speed by the tensile tester. For example, the tension speed may be 100 mm/min, 90 mm/min, 80 mm/min, 70 mm/min, 60 mm/min, 50 mm/min, 40 mm/min, or 30 mm/min.
In addition, the lyocell material and/or monofilament may be stabilized under constant temperature and humidity conditions prior to measurement of tensile strength. For example, a constant temperature condition may be a temperature of 20±2 °C, and a constant humidity condition may be a humidity of 65±4 %RH. In addition, stabilization may be performed for 24 hours or more.
Although not particularly limited, a lyocell material prepared to satisfy the tensile strength described above may be used in a smoking article.

[Breaking elongation]

In some embodiments, in a lyocell material, a breaking elongation of a monofilament may be in a range of 2.0 % to 10.0 %. For example, an upper limit of the breaking elongation of the monofilament may be 9.5 %, 9.0 %, 8.5 %, 8.0 %, 7.5 %, 7.0 %, 6.5 %, 6.0 %, 5.5 %, 5.0 %, 4.5 %, 4.0 %, 3.5 %, or 3.0 %, and a lower limit of the breaking elongation may be 2.5 %, 3.0 %, 3.5 %, 4.0 %, 4.5 %, or 5.0 %.
A breaking elongation of the lyocell material may be measured through a tensile tester. Although not particularly limited, a low-speed extension type tensile tester (for example, a low-speed extension type tensile tester manufactured by Instron) may be considered as a tensile tester. For evaluation of a breaking elongation, a sample (for example, a monofilament) may be taken from the lyocell material. The sample may be stretched at a constant tension speed by the tensile tester. For example, the tension speed may be 100 mm/min, 90 mm/min, 80 mm/min, 70 mm/min, 60 mm/min, 50 mm/min, 40 mm/min, or 30 mm/min.
In addition, the lyocell material and/or monofilament may be stabilized under constant temperature and humidity conditions prior to measurement of a breaking elongation. For example, a constant temperature condition may be a temperature of 20±2 °C, and a constant humidity condition may be a humidity of 65±4 %RH. In addition, stabilization may be performed for 24 hours or more.
Although not particularly limited, a lyocell material prepared to satisfy the breaking elongation described above may be used in a smoking article.

[Binder]

In a non-limiting example, the lyocell material may further include a binder. The binder may be present, for example, on a surface of the lyocell multifilament or between the lyocell multifilaments (or the monofilaments). The binder may further increase the hardness of a filter for a smoking article, thereby preventing problems such as filter jamming during a process of preparing a filter or a process of preparing a smoking article (for example, a tobacco).
Types of available binders are not particularly limited, and any known binder may be used at a level that does not impede the purpose of the disclosure. For example, a binder capable of providing sufficient compatibility with an emulsion used in the present application, improving the hardness of a filter, and providing excellent bonding strength may be used.
In a non-limiting example, the binder may include a polyester-based binder, a cellulose-based binder, and/or a vinyl-based binder.
Although not particularly limited, as the polyester-based binder, a polyester binder including at least one selected from alkylene, arylene, and heteroarylene having 5 to 12 carbon atoms may be used.
Examples of the cellulose-based binder may include hydroxypropyl methyl cellulose (HPMC), ethyl cellulose (EC), methyl cellulose (MC), and/or carboxymethyl cellulose (CMC), but one or more embodiments are not limited thereto.
In some embodiments, the cellulose-based binder is selected from the group consisting of HPMC, EC, MC, CMC, and a combination thereof.
Examples of the vinyl-based binder may include polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and/or ethylene vinyl acetate (EVAc), but one or more embodiments are not limited thereto.
In some embodiments, the vinyl-based binder is selected from the group consisting of PVP, PVA, EVAc, and a combination thereof.
A method of applying the binder to a lyocell material (for example, coating) will be described below.

[Emulsion]

The lyocell material may include a lyocell multifilament, and an emulsion applied onto the lyocell multifilament. The emulsion may include: (a) an esterified product of a fatty acid having 16 or more carbon atoms and aliphatic monohydric alcohol; and (b) an esterified product of sorbitan and a fatty acid having 16 or more carbon atoms. The emulsion may be applied onto some or all of monofilaments or multifilaments constituting the lyocell material. In addition, the emulsion may permeate between filaments.
The emulsion including at least components (a) and (b) may have hydrophobicity. As a result, the lyocell material treated with the emulsion has excellent spreading properties.
In a specific example of the present application, the lyocell material may include a certain content of the emulsion. In this case, the content of the emulsion may refer to OPU (wt%) which will be described below. "OPU" may refer to "oil pick up ratio." In some embodiments, the lyocell material may include the emulsion in a content of 0.1 wt% or more with respect to 100 wt% of the total weight of the lyocell material. In particular, with respect to 100 wt% of the total weight of the lyocell material, the content of the emulsion may be 0.5 wt% or more, 1.0 wt% or more, 1.5 wt% or more, 2.0 wt% or more, 2.5 wt% or more, or 3.0 wt% or more, in particular, 3.5 wt% or more, 4.0 wt% or more, 4.2 wt% or more, 4.5 wt% or more, 5.0 wt% or more, 5.5 wt% or more, 6.0 wt% or more, 6.5 wt% or more, 7.0 wt% or more, 7.5 wt% or more, 8.0 wt% or more, 8.5 wt% or more, 9.0 wt% or more, or 9.5 wt% or more. An upper limit of the content of the emulsion may be, for example, 20.0 wt% or less, 18.0 wt% or less, 17.0 wt% or less, 16.0 wt% or less, 15.0 wt% or less, 14.5 wt% or less, 14.0 wt% or less, 13.5 wt% or less, 13.0 wt% or less, 12.5 wt% or less, 12.0 wt% or less, 11.5 wt% or less, 11.0 wt% or less, 10.5 wt% or less, 10 wt% or less, 9.5 wt% or less, 9.0 wt% or less, 8.5 wt% or less, 8.0 wt% or less, 7.8 wt% or less, or 7.6 wt% or less with respect to 100 wt% of the total weight of the lyocell material.
As a method of measuring the content (OPU) of the emulsion, for example, an extrusion method may be used. For example, a sample (for example, in a content of 2 g to 5 g, in particular, about 2.5 g) is collected (in this case, a weight of the collected sample is referred to as a sample weight), and the sample is put into a syringe-shaped container. A material of the above container is not particularly limited, but may be a stainless steel (SUS) material. Next, a solvent (for example, methanol) is put into the container into which the sample is put (an amount of the input solvent may be 10 ml or less (for example, about 8 ml)). When the solvent is added to the sample, a dropping method may be used, and a dropping speed may be uniformly adjusted. As described above, the solvent put into the container is allowed to drop on a plate from one end of the syringe-shaped container. In this case, the plate is pre-weighed (a measured weight is referred to as plate weight A), and the plate is installed such that the solvent dropped on the plate is removed away (that is, evaporated) at a temperature of 120 °C to 130 °C (for example, 125 °C). The above-described solvent addition and solvent dropping are performed three times, and pressure (for example, 98 kgf/cm² (10 kgf/cm²) or less, 49 N/cm² (5 kgf/cm²) or less, or 18 N/cm² to 39 N/cm² (2 kgf/cm² to 4 kgf/cm²)) is applied to the sample by using a syringe-shaped container to press the sample once. Thus, the solvent and emulsion present in the sample are sufficiently extruded. The sample is squeezed out by applying pressure until no solvent comes out. Afterwards, the plate is stored in a desiccator for 5 minutes to 10 minutes, and a weight (plate weight B) of the plate containing the sample is measured. Then, a content of the emulsion is calculated according to a formula below. Content of emulsion by extrusion (OPU, % or wt%) = {(plate weight B-plate weight A)/(sample weight)} × 100
In addition, a lyocell material that is used as a reference for the content of the emulsion may be a lyocell multifilament treated with an emulsion. For example, the lyocell material may be a lyocell multifilament to which primary emulsion treatment (to be described below) has been applied, a lyocell multifilament to which primary emulsion treatment and secondary emulsion treatment (to be described below) have been applied, or a lyocell multifilament treated with the above-described emulsion and also treated with a binder to be described below. In addition, the lyocell multifilament treated with the emulsion and/or the binder may be imparted with crimps.
In relation to the emulsion of the present application, component (a) may be a compound that may function as a type of lubricant or oil and may be a component that is harmless to the human body enough to be used in food. Component (a) may provide lubricity to fibers put into a crimp machine. When the lubricity is not sufficient, lyocells may clump together and may not escape the crimp machine, and when the lubricity is too high, there may be a problem in that a crimp is not formed properly. In consideration of such functions, a content of component (a) may be controlled as described below.
Regarding component (a), types of fatty acids having 16 or more carbon atoms forming the esterified product are not particularly limited. Fatty acids having 16 or more carbon atoms may be used as long as the fatty acids may provide esterified products that may be harmless to the human body enough to be used in food.
For example, saturated fatty acids and/or unsaturated fatty acids may be used as fatty acids having one or more 16 carbon atoms.
Examples of the saturated fatty acids may include a palmitic acid (hexadecanoic acid, CH₃(CH₂)₁₄COOH), a margaric acid (heptadecanoic acid, CH₃(CH₂)₁₅COOH), a stearic acid (octadecanoic acid, CH₃(CH₂)₁₆COOH), a nonadecylic acid (nonadecanoic acid, CH₃(CH₂)₁₇COOH), or an arachidic acid (eicosanoic acid, CH₃(CH₂)₁₈COOH). However, types of available saturated fatty acids are not limited thereto.
Examples of the unsaturated fatty acids may include a palmitoleic acid (CH₃(CH₂)sCH=CH(CH₂)₇COOH), an oleic acid (CH₃(CH₂)₇CH=CH(CH₂)₇COOH), a linoleic acid (C₁₈H₃₂O₂), or an arachidonic acid (C₂₀H₃₂O₂). However, types of available unsaturated fatty acids are not limited thereto.
In some embodiments, the fatty acid is selected from the group consisting of a palmitic acid, a margaric acid, a stearic acid, a nonadecylic acid, an arachidic acid, a palmitoleic acid, an oleic acid, a linoleic acid, and an arachidonic acid.
An upper limit of a carbon number of the fatty acid having 16 or more carbon atoms is not particularly limited, but may be, for example, 40 or less, 36 or less, 32 or less, 28 or less, 24 or less, or 20 or less.
Regarding component (a), types of aliphatic monohydric alcohols forming the ester compound are also not particularly limited. Aliphatic monohydric alcohols may be used as long as the aliphatic monohydric alcohols may provide esterified products that may be harmless to the human body enough to be used in foods.
For example, component (a) may be saturated aliphatic alcohol or unsaturated aliphatic alcohol, which may have a linear or branched form.
For example, the carbon number of the aliphatic monohydric alcohol may be in a range of 1 to 40. In particular, the carbon number of the aliphatic monohydric alcohol may be, for example, 4 or more, 8 or more, 12 or more, 16 or more, or 20 or more.
Examples of the aliphatic monohydric alcohol may include methanol, ethanol, butanol, lauryl alcohol, isotridecanol, or stearyl alcohol, but one or more embodiments are not limited thereto.
In some embodiments, the aliphatic monohydric alcohol is selected from the group consisting of methanol, ethanol, butanol, lauryl alcohol, isotridecanol, and stearyl alcohol.
In some embodiments, an esterified product of isotridecanol and a stearic acid (for example, isotridecyl stearate) may be used as component (a). However, types of available component (a) are not limited thereto.
As will be described below, a content of component (a) included in the emulsion may be adjusted in consideration of the function of the emulsion or the function of component (a).
Component (b), that is, esterified product of sorbitan and a fatty acid having 16 or more carbon atoms, is a compound that may function as a type of emulsifier and may be a component harmless to the human body enough to be used in food.
Since component (b) has both hydrophilicity and hydrophobicity due to polyhydric alcohol (that is, sorbitan), component (b) enables component (a), which provides lubricity to the fiber, to be well dispersed in water, which will be described below. In addition, components (a) and (b) used together not only may increase the dispersibility of the emulsion as described above, but also may lower a melting point, thereby ensuring the use/handling and stability of the emulsion. In consideration of such functions, a content of component (b) may be controlled as described below.
Regarding component (b), types of fatty acids having 16 or more carbon atoms forming the esterified product are not particularly limited. Fatty acids having 16 or more carbon atoms may be used as long as the fatty acids may provide esterified products that may be harmless to the human body enough to be used in food.
For example, saturated fatty acids and/or unsaturated fatty acids may be used as fatty acids having one or more 16 carbon atoms.
Examples of the saturated fatty acids may include a palmitic acid (hexadecanoic acid, CH₃(CH₂)₁₄COOH), a margaric acid (heptadecanoic acid, CH₃(CH₂)₁₅COOH), a stearic acid (octadecanoic acid, CH₃(CH₂)₁₆COOH), a nonadecylic acid (nonadecanoic acid, CH₃(CH₂)₁₇COOH), or an arachidic acid (eicosanoic acid, CH₃(CH₂)₁₈COOH). However, types of available saturated fatty acids are not limited thereto.
Examples of the unsaturated fatty acids may include a palmitoleic acid (CH₃(CH₂)sCH=CH(CH₂)₇COOH), an oleic acid (CH₃(CH₂)₇CH=CH(CH₂)₇COOH), a linoleic acid (C₁₈H₃₂O₂), or an arachidonic acid (C₂₀H₃₂O₂). However, types of available unsaturated fatty acids are not limited thereto.
In some embodiments, the fatty acid is selected from the group consisting of a palmitic acid, a margaric acid, a stearic acid, a nonadecylic acid, an arachidic acid, a palmitoleic acid, an oleic acid, a linoleic acid, and an arachidonic acid.
An upper limit of a carbon number of the fatty acid having 16 or more carbon atoms is not particularly limited, but may be, for example, 40 or less, 36 or less, 32 or less, 28 or less, 24 or less, or 20 or less.
In a specific example of the present application, an esterified product of sorbitan and an oleic acid (for example, sorbitan monooleate) may be used as component (b). However, types of available component (b) are not limited thereto.
A content of component (b) may be adjusted in consideration of the function of component (b) and the function of the emulsion as described above.
For example, the emulsion may include (b) an esterified product of sorbitan and a fatty acid having 16 or more carbon atoms in a content of 20 parts by weight to 60 parts by weight with respect to 100 parts by weight of (a) an esterified product of a fatty acid having 16 or more carbon atoms and aliphatic monohydric alcohol.
In particular, the emulsion of the present application may include component (b) in a content of 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, 40 parts by weight or more, 45 parts by weight or more, or 50 parts by weight or more with respect to 100 parts by weight of component (a). An upper limit of the content of component (b) with respect to 100 parts by weight of component (a) may be, for example, 55 parts by weight or less, 50 parts by weight or less, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, or 25 parts by weight or less. When the above range of the content is satisfied, a surface of a lyocell multifilament or lyocell tow treated with an emulsion may have hydrophobicity.
In an example, the emulsion may include (a) the esterified product of the fatty acid having 16 or more carbon atoms and aliphatic monohydric alcohol in a content of 40 wt% to 80 wt% with respect to 100 wt% of the total weight of the emulsion. In particular, the content of component (a) may be 45 wt% or more, 50 wt% or more, 55 wt% or more, 60 wt% or more, or 65 wt% or more, 70 wt% or more, or 75 wt% or more with respect to 100 wt% of the total weight of the emulsion. An upper limit of the content of component (a) may be, for example, 75 wt% or less, 70 wt% or less, 65 wt% or less, 60 wt% or less, 55 wt% or less, 50 wt% or less, or 45 wt% or less.
In an example, the emulsion may include an excess amount of component (a).
In an example, the emulsion may include (b) the esterified product of sorbitan and the fatty acid having 16 or more carbon atoms in a content of 15 wt% to 55 wt% with respect to 100 wt% of the total weight of the emulsion. In particular, the content of component (b) may be 20 wt% or more, 25 wt% or more, 30 wt% or more, 35 wt% or more, 40 wt% or more, 45 wt% or more, or 50 wt% or more with respect to 100 wt% of the total weight of the emulsion. An upper limit of the content of component (b) may be, for example, 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, or 25 wt% or less.
In an example, the emulsion may further include water. A small amount of water may assist in emulsifying.
A content of water is not particularly limited, but water may be included in the remaining content excluding the total content of components (a) and (b) with respect to 100 wt% of the total weight of the emulsion. The content of water in the emulsion (that is, the remaining content excluding the total content of the remaining components excluding water) may be, for example, 10 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, 2 wt% or less, or 1 wt% or less. A lower limit of the content of water may be, for example, 0 wt% or more, 0.1 wt% or more, 0.5 wt% or more, or 1 wt% or more.

[Spinning dope]

According to an example, there is provided a spinning dope including cellulose pulp and NMMO and having a complex viscosity of 10 Pa·s to 200 Pa·s.
In particular, a lower limit of the complex viscosity may be 20 Pa·s or more, 30 Pa·s or more, 40 Pa·s or more, 50 Pa·s or more, 60 Pa·s or more, 70 Pa·s or more, 80 Pa·s or more, 90 Pa·s or more, 100 Pa·s or more, 110 Pa·s or more, 120 Pa·s or more, 130 Pa·s or more, 140 Pa·s or more, 150 Pa·s or more, 160 Pa·s or more, 170 Pa·s or more, 180 Pa·s or more, or 190 Pa·s or more, and an upper limit of the complex viscosity may be 190 Pa·s or less, 180 Pa·s or less, 170 Pa·s or less, 160 Pa·s or less, 150 Pa·s or less, 140 Pa·s or less, 130 Pa·s or less, 120 Pa·s or less, 110 Pa·s or less, 100 Pa·s or less, 90 Pa·s or less, 80 Pa·s or less, 70 Pa·s or less, 60 Pa·s or less, 50 Pa·s or less, 40 Pa·s or less, 30 Pa·s or less, or 20 Pa·s or less.
When the spinning dope has a complex viscosity of less than 10 Pa·s, the spinning dope may have flowability that is unsuitable for spinning. As a result, an orientation of a monofilament may not be uniform, and a breakage of the monofilament may occur during spinning.
On the other hand, when the spinning dope has a complex viscosity exceeding 200 Pa·s, strong viscosity may limit the preparation of monofilaments having a small fineness. Furthermore, a discharge port included in a spinneret may be closed by the spinning dope. As a result, continuous preparation of a lyocell material may be fundamentally impossible.
For example, complex viscosity may be measured by vibrating the spinning dope at a frequency of 0.1 rad/s to 500 rad/s. In particular, the complex viscosity of the spinning dope may be measured by vibrating the spinning dope at a frequency of 20 rad/s.
In some embodiments, in the spinning dope, the complex viscosity may be measured by using a rotational rheometer. For example, a cone-plate type rheometer meter may be used. In addition, although not particularly limited, the complex viscosity may be measured at a temperature of 110 °C to 120 °C.
In an example, a content of cellulose in the spinning dope may be in a range of 5 wt% to 15 wt% with respect to 100 wt% of the total weight of the spinning dope. When the content of cellulose is too low, it is difficult to implement the properties of a lyocell fiber, and when the content exceeds the above range, it is difficult to dissolve cellulose in a solvent. In consideration of the difficulties, the content of cellulose in the spinning dope may be 6 wt% or more, 7 wt% or more, 8 wt% or more, 9 wt% or more, or 10 wt% or more with respect to 100 wt% of the total weight of the spinning dope, and an upper limit thereof may be, for example, 14 wt% or less, 13 wt% or less, 12 wt% or less, 11 wt% or less, 10 wt% or less, or 9 wt% or less, with respect to 100 wt% of the total weight of the spinning dope. The term "cellulose" may refer to "lyocell cellulose."
In some embodiments, the spinning dope may further include water. Accordingly, the spinning dope may include an aqueous solution of NMMO. The aqueous solution may include, for example, NMMO in a content of 80 parts by weight to 95 wt% and water in a content of 5 parts by weight to 20 parts by weight in consideration of a degree of dissolution of cellulose and a process temperature.
For example, the cellulose or cellulose pulp may include alpha-cellulose in a content of about 85 wt% to about 97 wt% with respect to 100 wt% of the total weight of the cellulose and/or cellulose pulp.
For example, the cellulose or cellulose pulp may include hemicellulose in a content of 1 wt% to 15 wt% with respect to 100 wt% of the total weight of the cellulose and/or cellulose pulp. By adjusting the content of the hemicellulose within the above range, the stable physical properties (for example, hardness or draw resistance implementation) and processability of a lyocell material may be more easily secured.
In addition, in some embodiments, a DPw of the cellulose may be in a range of 600 to 1,700. In some embodiments, the DPw refers to the number of repeating units and/or monomers of the cellulose, alpha-cellulose, and/or hemicellulose in the cellulose pulp.
Although not particularly limited, in order to prepare a spinning dope having a complex viscosity of 10 Pa·s to 200 Pa·s, cellulose pulp and a solvent of NMMO may be premixed, and/or a spinning dope may be extruded. Through premixing, the solubility of the cellulose pulp may be increased, and the uniformity of the spinning dope may be improved. By extruding the spinning dope, the spinning dope may be pressed and/or stirred, and the complex viscosity of the spinning dope may be adjusted and specified.
By using the spinning dope as described above, a lyocell multifilament satisfying a certain fineness, certain tensile strength, and/or a certain breaking elongation may be spun.

[Method of preparing lyocell material]

The present application relates to a method of preparing a lyocell material. Through the method, a lyocell material may be prepared and used in a smoking article.
In particular, the method of preparing a lyocell material includes: lyocell dope spinning; coagulation and multifilament obtainment; washing; emulsion treatment; and crimp imparting. In addition, the method of preparing a lyocell material may further include: binder treatment; and other operations. In some embodiments, the operations are performed in this stated order.
The emulsion treatment may be performed before the crimp imparting, after the crimp imparting, or before and after the crimp imparting.
Emulsion treatments may each independently be performed, for example, by spraying an emulsion with the above-described composition onto a lyocell multifilament or immersing the lyocell multifilament in the emulsion. As described above, the emulsion treatment may be performed such that a content of an emulsion (for example, OPU (wt%)) in a lyocell material satisfies a certain range.
The crimp imparting may be performed, for example, by applying steam and/or pressure to the lyocell multifilament.
The method of preparing a lyocell material according to a specific embodiment of the present application, including the emulsion treatment and the crimp imparting, will be described in more detail below. The method of the present application may be performed by including one or more of operations described below.

<Lyocell dope spinning (a)>

A corresponding operation is an operation of spinning a lyocell multifilament by using the spinning dope described above.
The spinning dope may be premixed prior to spinning. Additional devices may be used to premix the spinning dope. For example, the spinning dope may be premixed by a side feeder. The spinning dope may be premixed in the side feeder for a retention time of 1 s to 3 s.
In addition, a temperature inside the side feeder may be maintained constant. For example, the temperature inside the side feeder may be maintained at a temperature of 80 °C to 100 °C.
The spinning dope may be extruded by an extruder prior to spinning. The complex viscosity of the spinning dope may be adjusted and specified by pressing and/or stirring the spinning dope through the extruder.
In addition, a temperature inside the extruder may be maintained constant. For example, the temperature inside the extruder may be maintained at a temperature of 80 °C to 100 °C.
Spinning is performed by discharging the spinning dope through a spinneret. For example, a cross-sectional shape of a lyocell monofilament spun from the spinning dope may be adjusted according to a cross-sectional shape of a discharge port formed in the spinneret. As a type of a spinneret for discharging the spinning dope, for example, a spinneret including a discharge port with a multi-lobal cross section, may be used.
A nozzle temperature of the spinneret, in particular, a spinning temperature thereof, may be appropriately selected by a person skilled in the art. Considering that the viscosity of the spinning dope may vary according to the spinning temperature, and thus discharging may not be performed well, the spinning temperature may be, for example, in a range of 100 °C to 120 °C or 100 °C to 110 °C.
In some embodiments, the spinning may be performed under spinning conditions in which a fineness of a filament is controlled to be in a range of 1.67 dtex to 9.44 dtex (1.5 denier to 8.5 denier). For example, one or more spinning conditions of a discharge amount and a spinning speed of the spinning dope may be appropriately controlled so that a single fineness of a filament included in a lyocell material may satisfy a range of 1.67 dtex to 9.44 dtex (1.5 denier to 8.5 denier). In this case, a single fineness of a filament may refer to a fineness of a single monofilament separated from a multifilament.
In particular, the single fineness of the filament may be, for example, 8.33 dtex (7.5 denier) or less, 7.78 dtex (7.0 denier) or less, 7.22 dtex (6.5 denier) or less, 6.67 dtex (6.0 denier) or less, 6.11 dtex (5.5 denier) or less, 5.56 dtex (5.0 denier) or less, 5.00 dtex (4.5 denier) or less, 3.89 dtex (3.5 denier) or less, 3.33 dtex (3.0 denier) or less, 2.78 dtex (2.5 denier) or less, or 2.22 dtex (2.0 denier) or less. A lower limit of the single fineness of the filament may be, for example, 2.22 dtex (2.0 denier) or more, 2.78 dtex (2.5 denier) or more, 3.33 dtex (3.0 denier) or more, 3.89 dtex (3.5 denier) or more, 4.44 dtex (4.0 denier) or more, 5.00 dtex (4.5 denier) or more, 5.56 dtex (5.0 denier) or more, 6.11 dtex (5.5 denier) or more, 6.67 dtex (6.0 denier) or more, 7.22 dtex (6.5 denier) or more, or 7.78 dtex (7.0 denier) or more. Satisfying the above range may be more advantageous in implementing stable draw resistance and securing processability of a filter for a smoking article.
In particular, by adjusting the complex viscosity of the spinning dope, the single fineness of the filament may satisfy the above-described range. In particular, since the complex viscosity of the spinning dope satisfies a range of 10 Pa·s to 200 Pa·s, an orientation of the spinning dope and processability of the spinning may be secured simultaneously.

<Coagulation and multifilament obtainment (b)>

In a corresponding operation, the spun spinning dope may be coagulated, and a lyocell multifilament may be obtained.
For the coagulation, a method in which the spinning dope comes into contact with air and/or a coagulating solution may be used.
In an example, the coagulation may include: primary coagulation of supplying cooling air to a spun lyocell dope; and secondary coagulation of adding a primarily coagulated spinning dope to a coagulating solution to coagulate the spinning dope.
According to such a coagulation method, the lyocell dope discharged through the spinneret may be primarily coagulated in a space (air gap section) between the spinneret and a coagulation tank. For example, cooling air may be supplied to the air gap section from an air cooling part positioned inside the spinneret in a direction from the inside to the outside of the spinneret. In addition, primary coagulation may be achieved through a known so-called air quenching method or means in the related field.
In an example, an upper limit of a temperature of the cooling air used in the primary coagulation may be, for example, 15 °C or less. In particular, the cooling air may be air with a temperature of 14 °C or less, 13 °C or less, 12 °C or less, 11 °C or less, or 10 °C or less. When the above temperature is exceeded, the spinning dope may not be sufficiently coagulated by air, and spinning-related processability may not be good.
A lower limit of the temperature of the cooling air may be determined in consideration of spinning processability and/or cross-sectional uniformity of a filament. For example, when the temperature of the cooling air is less than 4 °C, a surface of the spinneret may cool, a surface of the filament may become non-uniform, and the spinning processability may also deteriorate. In consideration of this, the cooling air may have a temperature of 5 °C or more, 6 °C or more, 7 °C or more, 8 °C or more, or 9 °C or more.
A degree by which the cooling air is supplied may be adjusted in consideration of sufficient coagulation, spinning processability, and an influence on the physical properties of the filament. For example, the cooling air may be supplied to the discharged spinning dope at an air flow rate of 70 Nm³/h to 400 Nm³/h. In particular, the air flow rate may be 100 Nm³/h or more, 150 Nm³/h or more, 200 Nm³/h or more, or 250 Nm³/h or more, and an upper limit thereof may be, for example, 350 Nm³/h or less, 300 Nm³/h or less, 250 Nm³/h or less, 200 Nm³/h or less, or 150 Nm³/h or less.
After the primary coagulation as described above, the cooled spinning dope may be supplied to a coagulation tank or bath containing a coagulating solution (secondary coagulation). For proper coagulation, a temperature of the coagulating solution may be, for example, 30 °C or less or 25 °C or less. The temperature of the coagulating solution may be 10 °C or more, 15 °C or more, or 20 °C or more. When the above temperature is maintained, a coagulation speed may be appropriately maintained.
A type of a coagulating solution for the secondary coagulation as described above is not particularly limited. For example, the coagulating solution may include at least one selected from water and NMMO.
Although not particularly limited, when the coagulating solution includes water and NMMO, with respect to 100 wt% of the total weight of the coagulating solution, a content of water in the coagulating solution may be in a range of 60 wt% to 90 wt%, and a content of NMMO may be in a range of 10 wt% to 40 wt%. Alternatively, the coagulating solution may include water in a content of about 70 wt% to about 80 wt% and NMMO in a content of about 20 wt% to about 30 wt% with respect to 100 wt% of the total weight of the coagulating solution. By using sensors or the like, a concentration of the coagulating solution may be controlled to be maintained during a preparation process.

<Washing (c)>

If necessary, the washing may be performed on a lyocell multifilament after the above-described coagulation and multifilament obtainment. Through such washing, NMMO and/or other impurities remaining in the filament may be removed.
A method of performing washing is not particularly limited. For example, washing may be performed by introducing a coagulated lyocell multifilament into a washing tank by using a traction roller. Alternatively, the washing may be performed by spraying a washing solution while moving to a subsequent operation by a traction roller.
Components of the washing solution are not particularly limited. For example, the washing solution may include water and may further include known other additives.
In addition, in consideration of reuse after washing, the washing solution may be used by adjusting a temperature thereof to 100 °C or less.

<Emulsion treatment (d)>

If required, an operation of treating the lyocell multifilament with an emulsion may be performed. The operation may be an operation of applying an emulsion with the above-described components onto a surface of the filament. Friction applied to the filament may be reduced through emulsion treatment, and a crimp may be formed well in the crimp imparting which will be described below. When the emulsion treatment is performed twice or more as described below, the emulsion treatment may be referred to as primary emulsion treatment and secondary emulsion treatment according to the order.
Although not particularly limited, the emulsion treatment may be performed by immersing the lyocell multifilament in a bath filled with an emulsion such that the lyocell multifilament is completely immersed in the emulsion. Alternatively, the emulsion treatment may be performed by spraying the emulsion while moving to a subsequent operation by a traction roller.
In order to ensure that an amount of the emulsion applied onto the lyocell multifilament is constant after the emulsion treatment as described above, a process in which rolls or the like positioned before and/or after the emulsion treatment squeeze out an emulsion of a surface of the lyocell multifilament may be additionally performed.
In an example, the emulsion treatment may be performed such that a content (OPU (wt%)) of the emulsion is 1.0 wt% or more with respect to 100 wt% of a lyocell multifilament which has been at least treated with an emulsion. In this case, the lyocell multifilament which has been at least treated with the emulsion, for example, the lyocell material, may be a lyocell multifilament to which primary emulsion treatment has been applied, a lyocell multifilament to which primary emulsion treatment and secondary emulsion treatment (see the description below) have been applied, or a lyocell multifilament to which the emulsion treatment as described above and a binder described below have been applied together. In addition, the lyocell multifilament treated with the emulsion and/or the binder as described above may be imparted with crimps.
In particular, in the lyocell multifilament which has been at least treated with the emulsion, a content of the emulsion may be 0.5 wt% or more, 1.0 wt% or more, 1.5 wt% or more, 2.0 wt% or more, 2.5 wt% or more, or 3.0 wt% or more, in particular, 3.5 wt% or more, 4.0 wt% or more, 4.2 wt% or more, 4.5 wt% or more, 5.0 wt% or more, 5.5 wt% or more, 6.0 wt% or more, 6.5 wt% or more, 7.0 wt% or more, 7.5 wt% or more, 8.0 wt% or more, 8.5 wt% or more, 9.0 wt% or more, or 9.5 wt% or more with respect to 100 wt% of the total weight of the lyocell multifilament which has been at least treated with the emulsion. An upper limit of the content of the emulsion may be, for example, 20.0 wt% or less, 18.0 wt% or less, 17.0 wt% or less, 16.0 wt% or less, 15.0 wt% or less, 14.5 wt% or less, 14.0 wt% or less, 13.5 wt% or less, 13.0 wt% or less, 12.5 wt% or less, 12.0 wt% or less, 11.5 wt% or less, 11.0 wt% or less, 10.5 wt% or less, 10 wt% or less, 9.5 wt% or less, 9.0 wt% or less, 8.5 wt% or less, 8.0 wt% or less, 7.8 wt% or less, or 7.6 wt% or less with respect to 100 wt% of the total weight of the lyocell multifilament which has been at least treated with the emulsion. In this case, the above content may refer to a dry weight after a solvent (for example, water) or liquid component that may be included in the emulsion has evaporated.
When the lyocell multifilament is treated with the emulsion with the above-described composition within the above range of the content, the hydrophilic properties of the lyocell material may be supplemented.
In some cases, the emulsion may be dried after the emulsion treatment as described above.
In a specific example of the present application, one or more of the above-described operations may be controlled such that a single fineness of the filament constituting the lyocell multifilament may be in a range of 1.67 dtex to 9.44 dtex (1.5 denier to 8.5 denier). The single fineness of the filament may refer to a fineness of a single monofilament separated from a multifilament.
The single fineness of the filament may be, in particular, 8.33 dtex (7.5 denier) or less, 7.78 dtex (7.0 denier) or less, 7.22 dtex (6.5 denier) or less, 6.67 dtex (6.0 denier) or less, 6.11 dtex (5.5 denier) or less, 5.56 dtex (5.0 denier) or less, 5.00 dtex (4.5 denier) or less, 3.89 dtex (3.5 denier) or less, 3.33 dtex (3.0 denier) or less, 2.78 dtex (2.5 denier) or less, or 2.22 dtex (2.0 denier) or less. A lower limit of the single fineness of the filament may be, in particular, 2.22 dtex (2.0 denier) or more, 2.78 dtex (2.5 denier) or more, 3.33 dtex (3.0 denier) or more, 3.89 dtex (3.5 denier) or more, 4.44 dtex (4.0 denier) or more, 5.00 dtex (4.5 denier) or more, 5.56 dtex (5.0 denier) or more, 6.11 dtex (5.5 denier) or more, 6.67 dtex (6.0 denier) or more, 7.22 dtex (6.5 denier) or more, or 7.78 dtex (7.0 denier) or more. Satisfying the above range may be more advantageous in implementing stable draw resistance and securing processability of a filter for a smoking article.
Although not particularly limited, an operation controlled to secure the above range of the single fineness may be the above-described spinning. Alternatively, the above-described spinning, coagulation, washing, and emulsion treatment may all be controlled to secure the above ranges of the single fineness.

<Crimp imparting (e)>

The crimp imparting is an operation of applying pressure to a lyocell multifilament treated with an emulsion through steam and/or a press roller to obtain a crimped multifilament, for example, crimped tow. The crimp imparting may be referred to as crimping. As used herein, the terms "treated with emulsion" and "emulsified" may be used interchangeably.
Through crimping, waves may be provided to the lyocell multifilament, and fibers may have bulky properties. The crimping may be performed by using known crimp machines, such as a stuffer box and/or a steam box, and available crimp machines are not particularly limited as long as the crimp machines are devices capable of applying one or more of pressures which will be described below.
In an example, the crimp imparting may be performed by first supplying steam to the lyocell multifilament to preheat and swell the lyocell multifilament, and then pressing the lyocell multifilament with a press roller to form wrinkles in the lyocell multifilament. In this case, a steam box may be used to supply steam, and the steam box may be positioned in front of the crimp machine.
In an example, the crimp imparting may be performed in such a manner that pressing of the lyocell multifilament by the press roller and applying of steam are simultaneously performed.
In an example, the crimp imparting may be performed in such a manner that steam is supplied to the lyocell multifilament to preheat and swell the lyocell multifilament, and then pressing of the lyocell multifilament by the press roller and applying of steam are simultaneously performed.
In an example, the crimp imparting may be performed by applying steam with a pressure of 0.98 N/cm² to 19.61 N/cm² (0.1 kgf/cm² to 2.0 kgf/cm²) to the lyocell multifilament before the lyocell multifilament is put into the crimp machine (in particular, the press roller).
For example, steam with a pressure of 1.96 N/cm² (0.2 kgf/cm²) or more, 2.94 N/cm² (0.3 kgf/cm²) or more, 3.92 N/cm² (0.4 kgf/cm²) or more, 4.90 N/cm² (0.5 kgf/cm²) or more, or 5.88 N/cm² (0.6 kgf/cm²) or more may be supplied by the steam box. In addition, steam with a pressure of 14.71 N/cm² (1.5 kgf/cm²) or less, 13.73 N/cm² (1.4 kgf/cm²) or less, 12.75 N/cm² (1.3 kgf/cm²) or less, 11.77 N/cm² (1.2 kgf/cm²) or less, 10.79 N/cm² (1.1 kgf/cm²) or less, or 9.81 N/cm² (1.0 kgf/cm²) or less may be supplied. When the amount or pressure of supplied steam is less than the above range, a crimp may not be formed smoothly. When the above range is exceeded, since the flexibility of the filament is increased, excessive crimp may be provided to the filament in the crimp machine, and thus the filament may not pass through the crimp machine.
In an example, the crimp imparting may be performed by pressing the lyocell multifilament with a press roller to form wrinkles in the lyocell multifilament. In addition, steam may not be supplied prior to pressing, steam may not be supplied simultaneously with pressing, or steam may not be supplied prior to pressing and simultaneously with pressing.
In an example, the crimp imparting may be performed by applying a pressure of 14.71 N/cm² to 39.23 N/cm² (1.5 kgf/cm² to 4.0 kgf/cm²) to the lyocell multifilament put into the crimp machine by using a press roller.
For example, a pressure of 15.69 N/cm² (1.6 kgf/cm²) or more, 16.67 N/cm² (1.7 kgf/cm²) or more, 17.65 N/cm² (1.8 kgf/cm²) or more, 18.63 N/cm² (1.9 kgf/cm²) or more, 19.61 N/cm² (2.0 kgf/cm²) or more, 20.60 N/cm² (2.1 kgf/cm²) or more, 21.58 N/cm² (2.2 kgf/cm²) or more, 22.56 N/cm² (2.3 kgf/cm²) or more, 23.54 N/cm² (2.4 kgf/cm²) or more, or 24.52 N/cm² (2.5 kgf/cm²) or more may be applied to the lyocell multifilament through the press roller. In addition, a pressure of 38.25 N/cm² (3.9 kgf/cm²) or less, 37.27 N/cm² (3.8 kgf/cm²) or less, 36.29 N/cm² (3.7 kgf/cm²) or less, 35.31 N/cm² (3.6 kgf/cm²) or less, 34.33 N/cm² (3.5 kgf/cm²) or less, 33.35 N/cm² (3.4 kgf/cm²) or less, 32.37 N/cm² (3.3 kgf/cm²) or less, 31.39 N/cm² (3.2 kgf/cm²) or less, 30.41 N/cm² (3.1 kgf/cm²) or less, 29.42 N/cm² (3.0 kgf/cm²) or less, 28.44 N/cm² (2.9 kgf/cm²) or less, 27.46 N/cm² (2.8 kgf/cm²) or less, 26.48 N/cm² (2.7 kgf/cm²) or less, 25.50 N/cm² (2.6 kgf/cm²) or less, or 24.52 N/cm² (2.5 kgf/cm²) or less may be applied through the press roller.
When the pressure of the press roller is less than the above range, the desired number of crimps may not be formed sufficiently. When the pressure of the press roller exceeds the above range, a pressing force may be too strong, and thus the filament may not be smoothly put into the crimp machine or may not pass through the crimp machine (for example, the stuffer box). Wrinkles may be formed in the lyocell multifilament by the press roller that provides the pressure.
In an example, by using an upper plate, a pressure of 0.12 kgf/cm² to 2 kgf/cm² may be applied to the lyocell multifilament. In addition, the upper plate may apply pressure to the lyocell multifilament when the lyocell multifilament has passed through the press roller or while the lyocell multifilament is passing through the press roller.
For example, the pressure applied by the upper plate may be 1.96 N/cm² (0.2 kgf/cm²) or more, 2.94 N/cm² (0.3 kgf/cm²) or more, 3.92 N/cm² (0.4 kgf/cm²) or more, or 4.90 N/cm² (0.5 kgf/cm²) or more. In addition, a pressure of 14.71 N/cm² (1.5 kgf/cm²) or less, 13.73 N/cm² (1.4 kgf/cm²) or less, 12.75 N/cm² (1.3 kgf/cm²) or less, 11.77 N/cm² (1.2 kgf/cm²) or less, 10.79 N/cm² (1.1 kgf/cm²) or less, or 9.81 N/cm² (1.0 kgf/cm²) or less may be applied by the upper plate.
Furthermore, when the pressure of the upper plate, which vertically moves to impart uniform crimps after the lyocell multifilament passes through the press roller, is less than 0.98 N/cm² (0.1 kgf/cm²), since the upper plate may not be fixed due to a pressure inside the crimp machine (for example, the stuffer box), while tow remains in the crimp machine for a long time, the continuity of a process may not be maintained. When the pressure of the upper plate exceeds 2 kgf/cm², since steam inside the crimp machine may not be smoothly discharged, a shape of a crimp may be irregular.
In an example, in the crimp imparting, a doctor blade that applies a certain pressure to the lyocell multifilament may be applied. The doctor blade may adjust a residence time of a filament put into the crimp machine, thereby contributing to the adjustment of the number of crimps. The doctor blade may be positioned, for example, on a movement path of the lyocell multifilament that is pressed by the above-described press roller and then discharged from a roller pressing point.
In an example, the crimp imparting may be performed by applying a pressure of 0.98 N/cm² to 19.61 N/cm² (0.1 kgf/cm² to 2.0 kgf/cm²) to the lyocell multifilament, which has passed between the press rollers of the crimp machine, by using the doctor blade.
For example, the pressure applied by the doctor blade may be 1.96 N/cm² (0.2 kgf/cm²) or more, 2.94 N/cm² (0.3 kgf/cm²) or more, 3.92 N/cm² (0.4 kgf/cm²) or more, or 4.90 N/cm² (0.5 kgf/cm²) or more. In addition, a pressure of 14.71 N/cm² (1.5 kgf/cm²) or less, 13.73 N/cm² (1.4 kgf/cm²) or less, 12.75 N/cm² (1.3 kgf/cm²) or less, 11.77 N/cm² (1.2 kgf/cm²) or less, 10.79 N/cm² (1.1 kgf/cm²) or less, or 9.81 N/cm² (1.0 kgf/cm²) or less may be applied by the doctor blade.
In an example, the crimp imparting may be performed at a temperature ranging from 120 °C to 250 °C. When the temperature is too low, the effect of stabilizing the shape of the crimp may not be good, and when the temperature is too high, a concentration of fat and oil inside the crimp machine (for example, the stuffer box) may be increased, which may make it difficult to form the crimp. Therefore, in consideration of the above-described pressure of the steam or the like, a temperature may be appropriately controlled in a range of 130 °C or more, 140 °C or more, or 150°C or higher, and 200 °C or less, 180 °C or less, or 160 °C or less.

<Binder treatment (f)>

In an example, the method may further include an operation of treating the lyocell multifilament treated with the emulsion or the lyocell multifilament obtained through the crimp imparting with a binder.
When a filter for a smoking article is prepared by using the lyocell material (for example, lyocell tow), a binder may be additionally used. The binder may increase the hardness of a filter for a smoking article including a lyocell material, thereby preventing problems such as filter jamming during a process of preparing a filter or a process of preparing a tobacco.
A method of coating a lyocell material with a binder is not particularly limited. For example, binder treatment may be performed by immersing the lyocell multifilament in a bath filled with a binder and/or a binder solution such that the lyocell multifilament is completely immersed in the binder. Alternatively, binder coating may be performed on the lyocell multifilament by spraying and/or injecting the binder and/or the binder solution through a nozzle. Types and components of available binders are as described above, and thus descriptions thereof are omitted.
In an example, the binder and/or the binder solution may further include a solvent in addition to components described above. Examples of the solvent may include water, ethanol, propylene glycol, and/or glycerin, but one or more embodiments are not limited thereto. When the binder and/or the binder solution includes a solvent, a content of the solvent may be, for example, in a range of about 20 wt% to about 80 wt% or about 40 wt% to about 60 wt% with respect to 100 wt% of the total weight of the binder and/or the binder solution.
Such binder treatment may be performed at a level that may achieve the purpose of the above-described binder treatment. For example, the binder treatment may be performed such that a content of the binder satisfies 20 wt% or less, for example, a range of 8 wt% 0 15 wt%, with respect to 100 wt% of a lyocell multifilament treated with an emulsion and a binder. In this case, the above content may refer to a dry weight after a solvent or liquid component that may be included in the binder has evaporated.
After the binder is applied onto the lyocell multifilament, the binder may be dried. A drying temperature is not particularly limited, but, for example, drying may be performed at room temperature (about 10 °C to about 35 °C).

<Other operations (g)>

After the crimp imparting, appropriate post-treatment may be additionally performed.
In an example, secondary emulsion treatment (g1) may be additionally performed. Through the secondary emulsion treatment, flexibility may be further provided to tow. The secondary emulsion treatment may be performed in the same manner as or in accordance with the emulsion treatment (d) described above.
In particular, the secondary emulsion treatment may be performed by treating lyocell tow, which has undergone a process using a crimp machine, with an emulsion. The secondary emulsion treatment may function advantageously in various processes performed during the preparation of a filter for a smoking article. For example, the secondary emulsion treatment may allow fibers and filters to spread well even in air during a spreading process and also may restrict fibers from being cut during a stretching process.
The secondary emulsion treatment as described above may be performed before or after the binder treatment. Alternatively, the secondary emulsion treatment may be performed irrespective of whether the binder treatment is performed.
Even in a case in which the secondary emulsion treatment as described above is performed, a secondary emulsion treatment process may be performed such that a content or an OPU content of an emulsion in a material satisfies the range described above.
In an example, drying treatment (g2) may be additionally performed. Drying may be performed, for example, at a temperature in a range of 100 °C to 130 °C. A drying treatment manner or method is not particularly limited, and known technologies may be used. For example, the drying may be performed by applying hot air to tow, allowing the tow to pass through a temperature-controlled room, or leaving the tow for a certain period of time.
A lyocell material according to the disclosure may be obtained through the above-described method of preparing a lyocell material.
The lyocell material according to the disclosure may be a material obtainable through the above-described method of preparing a lyocell material.

[Smoking article]

Although not particularly limited, a lyocell material prepared through the method may be included in a smoking article. The smoking article may be an aerosol-generating article. The aerosol-generating article may include an aerosol-generating material or an aerosol-forming substrate.
For example, the lyocell material may be included in a combustion-type cigarette. As another example, the lyocell material may be included in a heated cigarette, and the heated cigarette may be used together with an aerosol generating device.
For example, when used as a heated smoking article, the smoking article may be separately inserted into an aerosol generating device. Here, the aerosol generating device may include an accommodation groove in which an aerosol-generating article may be accommodated, and in addition, may include a heater for heating the aerosol-generating article to generate aerosol, a control unit for controlling the overall operation of the aerosol generating device, a battery for providing power used for operating the aerosol generating device, and a detector for recognizing that the aerosol-generating article has been inserted into the aerosol generating device.
The smoking article may include a tobacco medium portion, a filter for a smoking article, and a wrapper, wherein the filter for a smoking article may be positioned at one end portion of the tobacco medium portion, for example, a rear end portion or a front end portion. The tobacco medium portion and the filter for a smoking article may each include a single segment or may each independently include a plurality of segments.
The tobacco medium portion may include a tobacco material, and the tobacco material may include nicotine. In addition, the tobacco medium may additionally include one or more excipients.
The excipients may include a binder, a filler, and other additives. For example, the tobacco medium included in the tobacco medium portion may be prepared in the form of granules including a tobacco material, an excipient, and the like.
For example, a filler may be additionally included to constantly maintain the shape, strength, and mass of the tobacco medium portion. For example, the lyocell material may be included in the tobacco medium portion. In addition, the lyocell material may be used as a filler.
The wrapper may be subdivided into cigarette paper for wrapping the tobacco medium portion, filter wrapping paper for wrapping the filter, and a tipping wrapper for coupling the tobacco medium portion and the filter.

[Filter for smoking article]

A lyocell material may be used in a filter for a smoking article. The lyocell material may be lyocell tow. In an example, the lyocell tow includes a lyocell multifilament imparted with crimps.
For example, the present application relates to a filter for a smoking article. The filter for a smoking article may include a lyocell material, and the lyocell material may be identical to that described above. In addition, the filter for a smoking article may include lyocell tow, and the lyocell tow may be identical to that described above.
In addition, the lyocell material may include an emulsion in a content of 0.1 wt% or more with respect to 100 wt% of the total weight of the lyocell material. In addition, an emulsion component and a content according to the specific example of the present application are as described above.
In an example, a single fineness of a filament constituting the lyocell multifilament may be in a range of 1.67 dtex to 9.44 dtex (1.5 denier to 8.5 denier). A specific numerical value is as described above.
In an example, the lyocell multifilament imparted with crimps may be a lyocell material having a total fineness of 1,667 tex to 6,111 tex (15,000 denier to 55,000 denier), and for example, the lyocell material may be lyocell tow. A specific numerical value is as described above.
In an example, the lyocell multifilament imparted with crimps may have 3.94 to 19.69 crimps per centimeter (10 to 50 crimps per inch). A specific numerical value is as described above.
In an example, the filter for a smoking article may further include a binder on a surface of the lyocell multifilament imparted with crimps or between the lyocell multifilaments imparted with crimps. The binder may increase the hardness of a filter for a smoking article prepared from tow, thereby preventing problems such as filter jamming during a process of preparing a filter or a process of preparing a tobacco. Types, components, and contents of available binders are as described above.
In an example, the filter for a smoking article may further include wrapping paper (which may be referred to as wrapper paper, filter paper, or filter wrapping paper). For example, the wrapping paper may be porous paper or non-porous paper that may wrap the above-described lyocell tow and may maintain a filter shape (for example, a cylinder or circular column).
In a specific embodiment of the present application, the filter for a smoking article may have a certain shape and a certain size.
For example, the filter may have a rod shape. In particular, the filter for a smoking article may have a shape such as a cylinder.
In addition, the filter may have a length of, for example, 10 nm to 50 mm. In particular, the length of the filter may have a lower limit of 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 an upper limit of 45 mm or less, 40 mm or less, 35 mm or less, 30 mm or less, 25 mm or less, 20 mm or less, or 15 mm or less.
In a specific example of the present application, the filter having the length may have a circular cross section, and a circumference of the circular cross section may be in a range of 10 mm to 40 mm. For example, the circumference of the filter may have a lower limit of 15 mm or more, 20 mm or more, 25 mm or more, 30 mm or more, or 35 mm or more, and an upper limit of 35 mm or less, 30 mm or less, 25 mm or less, 20 mm or less, or 15 mm or less.
In an example, the filter for a smoking article may include lyocell tow and filter wrapping paper. The lyocell tow and the filter wrapping paper are as described above, and thus descriptions thereof are omitted.
The wrapping paper may be porous paper or non-porous paper that may wrap the above-described lyocell tow and may maintain a filter shape (for example, a cylinder or circular column).
In an example, when porous wrapping paper is used, the wrapping paper may have a porosity of 10 coresta unit (CU) to 50,000 CU. A coresta unit may be defined as a volume flow rate (cm³min^-1) of air passing through a 1 cm² substrate sample (that is, porous wrapping paper) at a pressure difference of 1 kPa. In particular, a lower limit of the porosity of the wrapping paper may be, for example, 1,000 CU or more, 5,000 CU or more, 10,000 CU or more, 15,000 CU or more, 20,.000 CU or more, 25,000 CU or more, 30,000 CU or more, 35,000 CU or more, 40,000 CU or more, or 45,000 CU or more, and an upper limit thereof may be, for example, 45,000 CU or less, 40,000 CU or less, 35,000 CU or less, 30,000 CU or less, 25,000 CU or less, or 20,000 CU or less. In a specific example of the present application, the wrapping paper may have a porosity in a range of 22,000 CU to 26,000 CU or 23,000 CU to 25,000 CU.
In an example, a basis weight of the wrapping paper may be in a range of 15 g/cm² to 60 g/cm². In particular, a lower limit of the basis weight of the wrapping paper may be, for example, 20 g/cm² or more, 25 g/cm² or more, 30 g/cm² or more, 35 g/cm² or more, 40 g/cm² or more, 45 g/cm² or more, 50 g/cm² or more, or 55 g/cm² or more, and an upper limit thereof may be, for example, 55 g/cm² or less, 50 g/cm² or less, 45 g/cm² or less, 40 g/cm² or less, 35 g/cm² or less, 30 g/cm² or less, 25 g/cm² or less, or 20 g/cm² or less. In a specific example of the present application, the wrapping paper may have a basis weight of 16 g/cm² or more, 17 g/cm² or more, 18 g/cm² or more, 19 g/cm² or more, 20 g/cm² or more, or 21 g/cm² or more, and 25 g/cm² or less, 24 g/cm² or less, 23 g/cm² or less, 22 g/cm² or less, or 21 g/cm² or less.
Although not particularly limited, a weight of a filter having a rod shape may be 50 mg or more. In particular, the weight of the filter may have, for example, a lower limit of 100 mg or more, 150 mg or more, or 200 mg or more, and an upper limit of 500 mg or less, 450 mg or less, 400 mg or less, 350 mg or less, 300 mg or less, 250 mg or less, or 200 mg or less.
Other filters for a smoking article and materials included therein are as described above, and thus descriptions thereof are omitted.

[Method of preparing filter for smoking article]

For example, the present application relates to a method of preparing a filter for a smoking article. The method may be a method of preparing a filter for a lyocell smoking article as described above and may be a method including the above-described method of preparing a lyocell material.
Regarding the method of preparing a filter for a smoking article, the remaining processes excluding preparing of a filter are the same as processes described in the lyocell material described above, and thus descriptions thereof are omitted. In addition, descriptions overlapping the above descriptions are also omitted.
The preparing of the filter may be appropriately performed by a person skilled in the art according to a known method. For example, the filter may be prepared by forming wrapping paper filled with a lyocell material into a rod shape. Alternatively, the filter may be prepared by cutting filter paper filled with a lyocell material with a rod shape into an appropriate length. The wrapping paper is as described above.
Although not particularly limited, before the filter paper is filled with the lyocell material, the lyocell material may be further subjected to opening or plasticizer treatment. A surface area of the lyocell material may be increased by opening the lyocell material. For example, the lyocell material may be opened by applying an external force in a length direction, a width direction, and/or a thickness direction.
For example, the lyocell material used in preparing a filter for a smoking article may be lyocell tow.
Although not particularly limited, the filter for a smoking article may additionally include known cellulose acetate multifilaments at a level that does not impede the purpose of the disclosure. The cellulose acetate multifilament may be mixed with a lyocell multifilament. The cellulose acetate multifilament may be included in a segment distinguished from a segment including the lyocell multifilament.

Advantageous Effects of Invention

According to the present application, there may be provided a lyocell material for a smoking article filter, which is capable of replacing commercialized cellulose acetate (CA), and a filter for a smoking article including the same. In particular, there are provided a spinning dope having adjusted complex viscosity and a lyocell material having good orientation and spinnability using the same.

Mode for the Invention

Hereinafter, the operations and effects of the disclosure will be described in more detail through specific examples of the disclosure. However, this is presented as an example of the disclosure, and the scope of the disclosure is not limited thereby.
A lyocell material was prepared through processes as described in Preparation Example below. Conditions not specifically described are within the scope of the above description.

[Preparation Example]

Cellulose pulp having an alpha-cellulose content of 93.9 % and a DPw of 820 was put into a side feeder, and NMMO/H₂O solvent having a propyl gallate content of 0.01 wt% was added to perform premixing. A temperature of the side feeder was maintained at 90 °C, and a premixing residence time of the cellulose pulp and the solvent was adjusted within 1 second. Thus, a dope was prepared by appropriately mixing the cellulose pulp and the solvent, and the dope was put into an extruder. A temperature of the extruder was set in a range of 90 °C to 100 °C to operate the extruder, and a spinning dope having a complex viscosity of 14.6 Pa·s (@20rad/s) was prepared.
After that, a spinning temperature was maintained at 110 °C, a discharge amount and a spinning speed were appropriately adjusted, and the spinning dope was spun from a spinning nozzle. The spinning speed was 230 m/min, and a draft ratio of spinning was 16.2.
A spinning dope with a filament phase discharged from the spinning nozzle was supplied to a coagulating solution (a coagulating solution having a concentration of 75 wt% water and 25 wt% NMMO and a temperature of about 25 °C) in a coagulating tank through an air gap section. In this case, cooling air in the air gap section primarily solidifies the spinning dope at a temperature of 9.5 °C and an air flow rate of 200 Nm³/h. In addition, the concentration of the coagulating solution was continuously monitored by using a sensor and a refractometer.
A coagulated lyocell filament was washed. In particular, the filament was introduced into a traction roller, and NMMO remaining in the filament was removed by using a washing solution sprayed from a washing device. Then, the washed filament was immersed inside a bath designed to have a certain emulsion concentration.
The filament was treated at a pressure of 19.61 N/cm² (2 kgf/cm²) by using a nip roll installed in a bath discharge portion and put into a crimp machine to provide wrinkles. In particular, a pressure of a press roller was set to 24.52 N/cm² (2.5 kgf/cm²), and a pressure of a doctor blade was set to 4.90 N/cm² (0.5 kgf/cm²) to prepare tow.
In order to prevent static electricity and provide flexibility to the prepared tow, secondary emulsion treatment was performed, and immediately after treatment, a tow product, which was dried while passing through a continuous drying device set at a temperature of 120 °C, was obtained.
The prepared tow has a single fineness of 1.67 dtex to 9.44 dtex (1.5 denier to 8.5 denier), a total fineness of 3,333 tex to 5,000 tex (30,000 denier to 45,000 denier), and the number of crimps of 5.91 ea/cm to 15.75 ea/cm (15 ea/inch to 40 ea/inch).

[Examples]

Example 1

A lyocell material of Example 1 was prepared according to Preparation Example.

Examples 2 to 15

Lyocell materials were prepared according to Preparation Example, and complex viscosity of a spinning dope and spinning conditions were as shown in Table 1 below.

Comparative Examples 1 to 5

Lyocell materials were prepared according to Preparation Example, and complex viscosity of a spinning dope and spinning conditions were as shown in Table 1 below.
In the case of Comparative Examples 1 to 3, the continuous and uniform production of a lyocell multifilament was limited due to the entanglement and breakage of the lyocell monofilament during spinning.

In Comparative Example 4 and Comparative Example 5, a discharge port formed in a spinneret was partially closed by a spinning dope. As a result, the continuous spinning of the lyocell multifilament was limited.

[Table 1]

		Complex viscosity of spinning dope (Pa·s@20rad/s)	Spinning temperature (°C)	Draft ratio	Temperature of cooling air (°C)
	1	15.6	110	16.2	9.5
	2	15.6	110	8.3	9.5
	3	15.6	110	12.2	9.5
	4	15.6	110	2.5	9.5
	5	69.4	113	23.3	9.0
	6	69.4	113	14.0	9.0
	7	69.4	113	8.9	9.0
	8	69.4	113	5.3	9.0
Examples	9	105.7	115	25.1	9.0
	10	105.7	115	15.0	9.0
	11	105.7	115	9.6	9.0
	12	105.7	115	5.6	9.0
	13	175.9	118	24.7	9.0
	14	175.9	118	12.6	9.0
	15	175.9	118	7.4	9.0
Comparative Examples	1	9.5	110	16.2	9.0
	2	9.5	105	8.3	9.0
	3	9.5	100	2.3	9.0
	4	203.5	120	29.1	9.0
	5	203.5	125	2.3	9.0

Referring to Comparative Examples 1 to 3 in Table 1, it is confirmed that the entanglement and breakage of the monofilament during a spinning process are caused by the low complex viscosity of the spinning dope, in particular, a complex viscosity of less than 10 Pa·s.
In addition, referring to Comparative Example 4 and Comparative Example 5 in Table 1, it is confirmed that the closing of a discharge port during a spinning process is caused by the excessive complex viscosity of the spinning dope, in particular, a complex viscosity exceeding 200 Pa·s.

<Experiment 1: Evaluation of tensile strength and breaking elongation of lyocell material>

The tensile strength and breaking elongation of a monofilament of the lyocell material according to each of Examples and Comparative Examples were measured by using a low-speed extension type tensile tester manufactured by Instron. In particular, a tension speed was 60 mm/min. Prior to measurement, a specimen taken from the lyocell material was pre-dried at a temperature of 110 °C for 2 hours and left for 24 hours or more in a standard environment according to KS K 0901.

In Examples 1 to 15, the lyocell material was continuously prepared without the entanglement or breakage of the monofilament. On the other hand, in the case of Comparative Examples 1 to 3, a flying thread was generated in a content of 5 wt% or more, and thus spinnability was evaluated to be poor. In addition, in the case of Comparative Example 4 and Comparative Example 5, a drip was generated in a content of 5 wt% or more, and thus spinnability was evaluated to be poor. As a result, the preparation of the lyocell material was limited from Comparative Examples 1 to 5.

[Table 2]

		Spinnability	Single fineness (dtex (d))	Tensile strength of monofilament (N/tex (gf/d))	Breaking elongation of monofilament (%)
	1	Good	1.96 (1.76)	0.450 (5.10)	7.30
	2	Good	3.84 (3.46)	0.371 (4.20)	5.20
	3	Good	3.27 (2.94)	0.380 (4.30)	6.10
	4	Good	8.92 (8.03)	0.290 (3.28)	5.44
	5	Good	1.98 (1.78)	0.335 (3.80)	6.90
	6	Good	3.49 (3.14)	0.371 (4.20)	7.10
	7	Good	5.20 (4.68)	0.309 (3.50)	6.50
Examples	8	Good	8.73 (7.86)	0.353 (4.00)	7.00
	9	Good	1.99 (1.79)	0.347 (3.93)	7.33
	10	Good	3.32 (2.99)	0.323 (3.66)	7.28
	11	Good	5.18 (4.66)	0.363 (4.11)	5.27
	12	Good	8.86 (7.97)	0.365 (4.14)	5.59
	13	Good	2.70 (2.43)	0.330 (3.74)	6.52
	14	Good	5.31 (4.78)	0.366 (4.15)	5.70
	15	Good	9.02 (8.12)	0.496 (5.62)	3.90
Comparative Examples	1	Poor	-	-	-
	2	Poor	-	-	-
	3	Poor	-	-	-
	4	Poor	-	-	-
	5	Poor	-	-	-

Referring to Examples 1, 5, 9, and 13 of Table 2, it is confirmed that the lyocell materials according to Examples include a monofilament with a fineness, and also each monofilament has excellent tensile strength and breaking elongation. For example, it is confirmed that the lyocell material of Example 1 has a fineness of 1.96 dtex (1.76 d), and the tensile strength and breaking elongation thereof have high values of 0.450 N/tex (5.10 gf/d) and 7.30 %, respectively.
In addition, referring to Examples 1 to 15, the lyocell materials according to the Examples may provide a fineness of a monofilament in a wide range, and as a result, a wide range of choices for the lyocell material may be provided in a process of preparing a filter for a smoking article including the lyocell material.

Claims

A spinning dope comprising cellulose pulp and N-methylmorpholine N-oxide (NMMO),
wherein the spinning dope has a complex viscosity of 10 Pa·s to 200 Pa·s.
The spinning dope of claim 1, wherein the cellulose pulp comprises alpha-cellulose,
wherein a content of the alpha-cellulose in the cellulose pulp is 85 wt% or more with respect to 100 wt% of the cellulose pulp.
The spinning dope of claim 2, wherein the cellulose pulp further comprises hemicellulose,
wherein a content of the hemicellulose in the cellulose pulp is less than 15 wt% with respect to 100 wt% of the cellulose pulp.
The spinning dope of claim 1, wherein:
a degree of polymerization (DPw) of the cellulose pulp is in a range of 600 to 1,700;

the spinning dope further comprises water, wherein a content of the water in the spinning dope is in a range of 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of a total weight of the NMMO and the water; and/or

the complex viscosity is measured by vibrating the spinning dope at a frequency of 20 rad/s.
A lyocell material comprising a lyocell multifilament spun by using the spinning dope of any one of claims 1 to 4.
The lyocell material of claim 5, wherein the lyocell multifilament is imparted with crimps.
The lyocell material of claim 6, wherein the number of the crimps is in a range of 10 ea/inch to 60 ea/inch.
The lyocell material of claim 5, wherein the lyocell multifilament has a tensile strength of 1.5 gf/d to 7.0 gf/d, a breaking elongation of 2.0 % to 10.0 %, and/or a single fineness of 1.5 denier to 8.5 denier.
The lyocell material of claim 5, wherein the lyocell material has a total fineness of 15,000 denier to 55,000 denier and/or is lyocell tow
The lyocell material of claim 5, wherein the lyocell material is used for a filter for a smoking article.
A filter for a smoking article, comprising the lyocell material of any one of claims 5 to 10.
A smoking article comprising the filter for a smoking article of claim 11.
A method of preparing a lyocell material, the method comprising:
lyocell dope spinning;

coagulation and lyocell multifilament obtainment;

washing;

emulsion treatment; and

crimp imparting,

wherein the lyocell dope spinning is performed by using a spinning dope including cellulose pulp and N-methylmorpholine N-oxide (NMMO), and

the spinning dope has a complex viscosity of 10 Pa·s to 200 Pa·s.
The method of claim 13, wherein the cellulose pulp comprises alpha-cellulose,
wherein a content of the alpha-cellulose in the cellulose pulp is 85 wt% or more with respect to 100 wt% of the cellulose pulp.
The method of claim 13, wherein the spinning dope further comprises water,
wherein a content of the water in the spinning dope is in a range of 5 parts by weight to 20 parts by weight with respect to 100 parts by weight of a total weight of the NMMO and the water.