Spunbond non-woven fabrics for filter, and method for preparing same

Abstract

The present invention relates to spunbond non-woven fabrics for a filter, and a method for preparing same. According to the present invention, the spunbond non-woven fabrics for a filter, and the method for preparing same are provided, the fabrics having low weight per unit area and high stiffness.

Description

Spunbond nonwoven fabric for filters and method for manufacturing the same

[0001] The present invention relates to a spunbond nonwoven fabric for a filter and a method for manufacturing the same.

[0002]

[0003] A filter is a material or device that creates a pressure difference on both sides of a partition through which a gas or liquid containing another phase passes to separate the other phase from the gas or liquid.

[0004] Nonwoven fabrics are typically used for filters. In particular, spunbond nonwoven fabrics are used in various industrial fields, including filters, due to their high productivity and excellent mechanical properties.

[0005] The performance of nonwoven fabrics for filters can vary depending on several factors that make up the nonwoven fabric. For example, the performance of nonwoven fabrics for filters can vary depending on factors such as the thickness, weight per unit area, and the fineness of the filaments that make up the nonwoven fabric.

[0006] Normally, nonwoven fabrics for filters are required to have high strength and stiffness to withstand the load generated during filtration.

[0007] The strength of nonwoven fabric increases as the weight per unit area and thickness of the nonwoven fabric increase, but this not only increases the cost of the nonwoven fabric but also causes the problem of wasting space in the filter.

[0008] Focusing on filtration efficiency in nonwoven filter fabrics tends to increase pressure loss, leading to reduced air permeability and liquid permeability, and consequently, a shortened service life. Conversely, focusing on air permeability and liquid permeability in nonwoven filter fabrics tends to extend service life, but also decrease filtration efficiency.

[0009] In addition, in the case of a mixed nonwoven fabric in which matrix filaments and binder filaments are separately radiated, there is a limitation in that it is difficult to secure high strength because only the intersection of the binder filaments is fixed.

[0010]

[0011] The present invention provides a spunbond nonwoven fabric for a filter having a low weight per unit area and high strength.

[0012] And, the present invention provides a method for manufacturing the spunbond nonwoven fabric for the filter.

[0013]

[0014] According to one embodiment of the invention,

[0015] Comprising a fiber web including core-in-sheath type filaments,

[0016] The core-in-sheath type long fiber includes a core portion including a first polyester having a melting point of 250°C or higher and a sheath portion including a second polyester having a melting point of 160°C to 235°C,

[0017] The core-in-sheath type long fiber comprises the core portion and the sheath portion in a weight ratio of 65:35 to 85:15,

[0018] The second polyester has an intrinsic viscosity (IV) that is 0.05 dl / g to 0.1 dl / g higher than the first polyester.

[0019] Spunbond nonwoven fabric for filters is provided.

[0020]

[0021] According to another embodiment of the invention,

[0022] A step of obtaining a core-in-sheath type filament including a core portion including the first polyester and a sheath portion including the second polyester by composite spinning a first polyester having a melting point of 250°C or higher and a second polyester having a melting point of 160°C to 235°C;

[0023] A step of forming a fiber web by stacking the core-in-sheath type long fibers on a net conveyor, and

[0024] A step of heat treating the above fiber web under pressure to form a spunbond nonwoven fabric;

[0025] The core-in-sheath type long fiber comprises the core portion and the sheath portion in a weight ratio of 65:35 to 85:15,

[0026] The second polyester has an intrinsic viscosity (IV) that is 0.05 dl / g to 0.1 dl / g higher than the first polyester.

[0027] A method for manufacturing the above spunbond nonwoven fabric for a filter is provided.

[0028]

[0029] Hereinafter, a spunbond nonwoven fabric for a filter and a method for manufacturing the same according to embodiments of the present invention will be described in more detail.

[0030]

[0031]

[0032] Unless explicitly stated otherwise in this specification, terminology is used only to describe specific embodiments and is not intended to limit the invention.

[0033] As used herein, the singular forms also include the plural forms unless the context clearly dictates otherwise.

[0034] As used herein, the term "including" means specifying a particular characteristic, region, integer, step, operation, element and / or component, but does not exclude the presence or addition of other particular characteristics, regions, integers, steps, operations, elements, components and / or groups.

[0035] In this specification, a “core-in-sheath type filament” means a filament having a shape consisting of a core portion and a sheath portion surrounding the outer surface of the core portion, and in which the core portion and the sheath portion contain polymers of the same or different compositions.

[0036] In this specification, terms including ordinal numbers, such as "first" and "second," are used to distinguish one component from another and are not limited by the ordinal numbers. For example, within the scope of the present invention, the first component may also be referred to as the second component, and similarly, the second component may be referred to as the first component.

[0037] As used herein, "denier" is a unit of fineness based on the mass (grams) per 9000 meters of fiber length. For example, 1 denier can be expressed as 1 g / 9000 m, or 0.11 mg / m, or 0.11 tex.

[0038] As used herein, "room temperature" means a temperature in the range of 15°C to 30°C. Specifically, within the temperature range, room temperature may be 15°C or higher, or 16°C or higher, or 17°C or higher, or 18°C ​​or higher, or 19°C or higher, or 20°C or higher; and 30°C or lower, or 29°C or lower, or 28°C or lower, or 27°C or lower, or 26°C or lower.

[0039] And, in this specification, unless specifically defined otherwise, the temperature at which measurement or evaluation of numerical characteristics is performed may be the above-mentioned room temperature.

[0040]

[0041] According to one embodiment of the invention,

[0042] Comprising a fiber web including core-in-sheath type filaments,

[0043] The core-in-sheath type long fiber includes a core portion including a first polyester having a melting point of 250°C or higher and a sheath portion including a second polyester having a melting point of 160°C to 235°C,

[0044] The core-in-sheath type long fiber comprises the core portion and the sheath portion in a weight ratio of 65:35 to 85:15,

[0045] The second polyester has an intrinsic viscosity (IV) that is 0.05 dl / g to 0.1 dl / g higher than the first polyester.

[0046] Spunbond nonwoven fabric for filters is provided.

[0047]

[0048] In general, the strength of nonwoven fabric increases as the weight per unit area and thickness of the nonwoven fabric increase, but this not only increases the cost of the nonwoven fabric but also wastes space in the filter.

[0049] As a result of the research of the present inventors, it was confirmed that a spunbond nonwoven fabric satisfying the configurations as described above has a low weight per unit area and high stiffness, and thus can be suitably used as a filter medium and filter support, etc. The spunbond nonwoven fabric for filters has excellent stiffness as well as air permeability and quality index, and thus can contribute to improving filter performance in various fields.

[0050] The above spunbond nonwoven fabric can be preferably used as a filter medium and filter support in air purification systems and air conditioning (HVAC) systems.

[0051]

[0052] In one embodiment, the spunbond nonwoven fabric for the filter comprises a fibrous web comprising core-in-sheath type long fibers.

[0053] The core-in-sheath type long fiber has a form consisting of a core portion and a sheath portion that surrounds the outer surface of the core portion, and the core portion and the sheath portion may contain polymers having the same or different compositions.

[0054] Preferably, in order to secure the mechanical properties of the core-in-sheath type long fiber, the core portion may be made of a polyester having a relatively high melting point. In addition, in order to provide sufficient bonding and fixation to the fiber web including the core-in-sheath type long fiber, the sheath portion may be made of a polyester having a relatively low melting point.

[0055] Specifically, the core-in-cis type long fiber includes a core portion including a first polyester having a melting point of 250°C or higher and a sheath portion including a second polyester having a melting point of 160°C to 235°C.

[0056]

[0057] It is preferable that the above first polyester has a melting point of 250°C or higher, or from 250°C to 265°C, or from 250°C to 260°C, or from 255°C to 260°C.

[0058] For example, the first polyester may be at least one compound selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polytetrafluoroethylene, and copolymers thereof that meet the melting point range.

[0059]

[0060] It is preferable that the second polyester has a melting point of 160°C to 235°C, or 180°C to 235°C, or 180°C to 230°C, or 200°C to 230°C.

[0061] For example, the second polyester may be at least one compound selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polytetrafluoroethylene, and copolymers thereof that meet the melting point range.

[0062] As another example, the second polyester may be a copolyester or polyamide-based resin that satisfies the melting point range. The copolyester may be a polyester copolymerized with adipic acid, isophthalic acid, and neopentyl glycol. The polyamide-based resin may be at least one selected from the group consisting of nylon 6, nylon 66, nylon 46, nylon 11, nylon 12, nylon 610, nylon 612, and a copolymer of nylon 6 / 66.

[0063]

[0064] In one embodiment, the second polyester preferably has an intrinsic viscosity (IV) that is 0.05 dl / g to 0.1 dl / g higher than that of the first polyester. Here, the intrinsic viscosity of the polyester is a value measured at room temperature.

[0065] In order to ensure that the effect according to the above implementation example can be sufficiently expressed, the second polyester preferably has an intrinsic viscosity that is at least 0.05 dl / g higher than that of the first polyester. However, if the difference in intrinsic viscosity between the first and second polyesters becomes too large, it may become difficult to manufacture the core-in-sheath type long fiber through melt spinning, and the mechanical properties of the long fiber may deteriorate. Therefore, it is preferable that the second polyester has an intrinsic viscosity that is higher than that of the first polyester, but the difference is 0.1 dl / g or less.

[0066] Specifically, the second polyester has a higher intrinsic viscosity than the first polyester, but the difference may be 0.05 dl / g or more, or 0.05 dl / g to 0.1 dl / g, or 0.06 dl / g to 0.1 dl / g, or 0.06 dl / g to 0.09 dl / g.

[0067]

[0068] In one embodiment, the first polyester may have an intrinsic viscosity of 0.65 dl / g to 0.75 dl / g, or 0.65 dl / g to 0.74 dl / g, or 0.65 dl / g to 0.73 dl / g, or 0.65 dl / g to 0.72 dl / g.

[0069] And, the second polyester may have an intrinsic viscosity of 0.70 dl / g to 0.85 dl / g, or 0.70 dl / g to 0.84 dl / g, or 0.70 dl / g to 0.83 dl / g, or 0.70 dl / g to 0.82 dl / g, or 0.70 dl / g to 0.80 dl / g, or 0.70 dl / g to 0.75 dl / g while satisfying the above-described intrinsic viscosity condition compared to the first polyester.

[0070] As a non-limiting example, the intrinsic viscosity of the above polyesters can be adjusted to a required range depending on the conditions of the solid-state polymerization reaction to obtain the polyester.

[0071]

[0072] According to one embodiment, the core-in-cis type long fiber preferably comprises the core portion and the cis portion in a weight ratio of 65:35 to 85:15.

[0073] In order to provide sufficient bonding strength to the fiber web including the core-in-sheath type filaments while enabling the effects according to the above-described embodiment to be realized, the sheath portion is preferably 15 wt% or more based on the weight of the core portion and the sheath portion. However, if the content of the sheath portion is too high, the spinnability of the filaments may deteriorate, and the content of the core portion may relatively decrease, thereby deteriorating the mechanical properties of the filaments. Therefore, the sheath portion is preferably 35 wt% or less, or 30 wt% or less, or 25 wt% or less based on the weight of the core portion and the sheath portion.

[0074] Specifically, in the core-in-sheath type long fiber, the weight ratio of the core portion and the sheath portion may be 65:35 to 85:15, or 70:30 to 85:15, or 75:25 to 85:15.

[0075]

[0076] According to one embodiment, the core-in-sheath type long fiber preferably has a fineness of 2 denier to 5 denier.

[0077] In order to maintain the core-in-sheath shape during the spinning process of the filament and to ensure an appropriate level of air permeability in the nonwoven fabric, the long fiber preferably has a fineness of 2 denier or more. However, in order to prevent deterioration of spinnability and operability, such as pack leakage, the long fiber preferably has a fineness of 5 denier or less.

[0078] Specifically, the core-in-sheath type long fiber may have a fineness of 2.0 denier to 5.0 denier, or 2.5 denier to 5.0 denier, or 2.5 denier to 4.5 denier, or 2.5 denier to 4.0 denier, or 2.5 denier to 3.5 denier.

[0079]

[0080] In one embodiment, the spunbond nonwoven fabric has a density of 0.30 g / cm 3 0.38 g / cm 3 It is desirable to have an apparent density of .

[0081] The apparent density of the above spunbond nonwoven fabric is calculated by the following equation.

[0082] *Apparent density (g / cm) 3 ) = Weight per unit area (g / m 2 ) / Thickness (mm) / 1000

[0083] In order to ensure that the spunbond nonwoven fabric has an appropriate level of mechanical properties and density, the spunbond nonwoven fabric has a density of 0.30 g / cm 3 It is desirable to have an apparent density of 0.38 g / cm. However, if the apparent density is excessively high, the pressure loss may increase, which may lower the air permeability and shorten the service life. Therefore, the spunbond nonwoven fabric should have an apparent density of 0.38 g / cm. 3 It is desirable to have an apparent density below.

[0084] Specifically, the spunbond nonwoven fabric has a density of 0.30 g / cm 3 0.38 g / cm 3 , or 0.32 g / cm 3 0.38 g / cm 3 , or 0.32 g / cm 3 0.36 g / cm 3 It can have an apparent density of .

[0085]

[0086] The above spunbond nonwoven fabric can have high strength and air permeability while having a low weight per unit area by satisfying the above-described characteristics.

[0087]

[0088] In one embodiment, the spunbond nonwoven fabric has a density of 130 g / m 2 170 g / m 2It has a weight per unit area of ​​.

[0089] In order to ensure that an appropriate level of mechanical properties can be secured, the weight per unit area of ​​the spunbond nonwoven fabric is 130 g / m 2 It is desirable that the strength of the nonwoven fabric be higher as the weight per unit area and thickness of the nonwoven fabric increase, but this not only increases the cost of the nonwoven fabric but also causes a problem of wasted space in the filter. Therefore, the weight per unit area of ​​the spunbond nonwoven fabric is 170 g / m 2 The following is desirable.

[0090] Specifically, the spunbond nonwoven fabric has a density of 130 g / m 2 170 g / m 2 , or 130 g / m 2 160 g / m 2 , or 130 g / m 2 150 g / m 2 , or 135 g / m 2 150 g / m 2 , or 135 g / m 2 145 g / m 2 It can have a weight per unit area of ​​.

[0091]

[0092] In one embodiment, the spunbond nonwoven fabric has a stiffness of at least 1000 mgf. The spunbond nonwoven fabric may have a stiffness of at least 1000 mgf in at least one of the longitudinal and transverse directions.

[0093] To ensure filter performance, the spunbond nonwoven fabric preferably has a stiffness of 1000 mgf or higher. However, if the stiffness is too high, the quality index of the spunbond nonwoven fabric may deteriorate. Therefore, the spunbond nonwoven fabric preferably has a stiffness of 1300 mgf or lower.

[0094] Specifically, the spunbond nonwoven fabric may have a strength of 1000 mgf or more, or 1000 to 1300 mgf, or 1010 to 1300 mgf, or 1010 to 1250 mgf.

[0095]

[0096] In one embodiment, the spunbond nonwoven fabric has a 30 cm according to the standard test method of ASTM D737-18 (2023). 3 / cm 2 / sec or more. Specifically, the spunbond nonwoven fabric has an air permeability of 30 cm 3 / cm 2 / sec or more, or 30 to 85 cm 3 / cm 2 / sec, or 40 to 85 cm 3 / cm 2 / sec, or 50 to 85 cm 3 / cm 2 / sec, or 60 to 85 cm 3 / cm 2 / sec, or 65 to 85 cm 3 / cm 2 / sec, or 67 to 80 cm 3 / cm 2 / sec can have an air permeability of .

[0097]

[0098] As a non-limiting example, the spunbond nonwoven fabric may have a density of 135±5 g / m 2 Tensile strength of 1000 to 1300 mgf, or 1050 to 1300 mgf, or 1050 to 1250 mgf, under weight per unit area; and 30 to 85 cm 3 / cm 2 / sec, or 40 to 85 cm 3 / cm 2 / sec, or 50 to 85 cm 3 / cm 2 / sec, or 60 to 85 cm 3 / cm 2 / sec, or 65 to 85 cm 3 / cm 2 / sec air permeability.

[0099]

[0100]

[0101] According to another embodiment of the invention,

[0102] A step of obtaining a core-in-sheath type filament including a core portion including the first polyester and a sheath portion including the second polyester by composite spinning a first polyester having a melting point of 250°C or higher and a second polyester having a melting point of 160°C to 235°C;

[0103] A step of forming a fiber web by stacking the core-in-sheath type long fibers on a net conveyor, and

[0104] A step of heat treating the above fiber web under pressure to form a spunbond nonwoven fabric;

[0105] The core-in-sheath type long fiber comprises the core portion and the sheath portion in a weight ratio of 65:35 to 85:15,

[0106] The second polyester has an intrinsic viscosity (IV) that is 0.05 dl / g to 0.1 dl / g higher than the first polyester.

[0107] A method for manufacturing the above spunbond nonwoven fabric for a filter is provided.

[0108]

[0109] According to one embodiment, the spunbond nonwoven fabric for the filter can be manufactured by a method of forming a fiber web including the core-in-sheath type long fiber by melt-spinning a first polyester and a second polyester and heat-treating the same under pressure.

[0110]

[0111] In the above manufacturing method, the respective properties of the first polyester, the second polyester, and the core-in-sheath type long fiber are as described above.

[0112]

[0113] In one embodiment, the first polyester and the second polyester can be independently melted and compositely radiated through a core-in-cis type spinneret to form the core-in-cis type long fiber.

[0114] In the above radiation process, it is preferable that the weight ratio of the core part including the first polyester and the sheath part including the second polyester is adjusted to 65:35 to 85:15.

[0115]

[0116] In the above spinning process, the spinning speed and tension can be controlled so that the core-in-sheath type long fiber can have a fineness of 2 denier to 5 denier.

[0117] For example, the step of obtaining the core-in-sheath type long fiber is preferably performed at a spinning speed of 4000 m / min to 6000 m / min, or 4500 m / min to 6000 m / min, or 4500 m / min to 5500 m / min. In order to form filaments with an appropriate degree of crystallinity, the spinning speed is preferably 4000 m / min or more, or 4500 m / min or more. However, if the spinning speed is excessive, filament entanglement may occur during the spinning process, which may lower the uniformity of the nonwoven fabric. Therefore, the spinning speed is preferably 6000 m / min or less, or 5500 m / min or less.

[0118]

[0119] The above core-in-sheath type long fibers are laminated on a continuously moving net conveyor by conventional opening methods such as electrostatic charging, collision plate, and air current diffusion to form a fiber web.

[0120]

[0121] Next, a step of heat treating the fiber web under pressure to form a spunbond nonwoven fabric is performed.

[0122] The above step is a step of heat-bonding the long fibers forming the fiber web to obtain a spunbond nonwoven fabric. The heat treatment can be performed at a temperature of 100°C to 200°C. For example, a spunbond nonwoven fabric with appropriate smoothness and thickness is obtained by passing the fiber web through a roller heated to about 200°C. Conventional devices such as a calendar roller, a smooth roller, and an embossing roller can be used in the above step. The roller is heated to a temperature capable of melting the sheath portion of the core-in-sheath type long fiber to an extent that it can be bonded.

[0123]

[0124] According to the present invention, a spunbond nonwoven fabric for a filter having a low weight per unit area and high strength and a method for manufacturing the same are provided.

[0125]

[0126] Hereinafter, preferred embodiments are presented to aid understanding of the invention. However, the following examples are intended only to illustrate the invention and are not intended to limit the invention to these embodiments.

[0127]

[0128] Example 1

[0129] Polyethylene terephthalate (PET; first polyester) having an intrinsic viscosity of 0.65 dl / g and a melting point of 255°C and copolyester (Co-PET; second polyester) having an intrinsic viscosity of 0.73 dl / g and a melting point of 230°C were each melted using a continuous extruder at 280°C.

[0130] The melts of the first and second polyesters were continuously spun through a spinneret equipped with a core-in-sheath type spinneret, thereby continuously obtaining core-in-sheath type filaments having a core portion made of the first polyester and a sheath portion made of the second polyester. At this time, the weight ratio of the core portion and the sheath portion was adjusted to be 85:15. After the filaments spun through the spinneret were solidified with cooling air, they were drawn at a spinning speed of 5000 m / min using a high-pressure air drawing device, thereby obtaining filaments having a fineness of 2.9 denier.

[0131] The obtained filaments were laminated on a continuously moving net conveyor to form a fiber web. The fiber web was passed through a smooth roller and an embossing roller maintained at 200°C and 35 N / mm to produce a spunbond nonwoven fabric.

[0132]

[0133] Example 2

[0134] A spunbond nonwoven fabric was manufactured using the same method as Example 1, except that the discharge amount was adjusted so that the weight ratio of the core portion and the sheath portion was 80:20.

[0135]

[0136] Example 3

[0137] A spunbond nonwoven fabric was manufactured using the same method as Example 1, except that the discharge amount was adjusted so that the weight ratio of the core portion and the sheath portion was 75:25.

[0138]

[0139] Example 4

[0140] A spunbond nonwoven fabric was manufactured in the same manner as in Example 1, except that a copolymerized polyester (Co-PET) having an intrinsic viscosity of 0.71 dl / g and a melting point of 230°C was used as the second polyester.

[0141]

[0142] Comparative Example 1

[0143] Polyethylene terephthalate (PET; first polyester) having an intrinsic viscosity of 0.65 dl / g and a melting point of 255°C and copolyester (Co-PET; second polyester) having an intrinsic viscosity of 0.73 dl / g and a melting point of 230°C were each melted using a continuous extruder at 280°C.

[0144] The melts of the first and second polyesters were spun through a nozzle having a circular cross-sectional discharge hole to form first and second polyester filaments each having a fineness of 2.9 denier.

[0145] The first polyester filament and the second polyester filament were mixed in a weight ratio of 80:20 and laminated on a continuously moving net conveyor to form a fiber web.

[0146] The above fiber web was passed through a smooth roller and an embossing roller maintained at 200°C and 35 N / mm to produce a spunbond nonwoven fabric.

[0147]

[0148] Comparative Example 2

[0149] The same method as Example 1 was used, except that the discharge amount was adjusted so that the weight ratio of the core part and the sheath part was 60:40.

[0150]

[0151] Comparative Example 3

[0152] A spunbond nonwoven fabric was manufactured using the same method as Example 1, except that the discharge amount was adjusted so that the weight ratio of the core portion and the sheath portion was 90:10.

[0153]

[0154] Comparative Example 4

[0155] The same method as Example 3 was performed, except that a copolymerized polyester (Co-PET) having an intrinsic viscosity of 0.60 dl / g and a melting point of 230°C was used as the second polyester.

[0156]

[0157] Comparative Example 5

[0158] A spunbond nonwoven fabric was manufactured in the same manner as in Example 3, except that a copolymerized polyester (Co-PET) having an intrinsic viscosity of 0.67 dl / g and a melting point of 230°C was used as the second polyester.

[0159]

[0160] 1st polyester 2nd polyester filament nonwoven fabric IV (dl / g) T m (℃)IV(dl / g)T m (℃) Fineness (De) Weight specific gravity (g / m) 2 ) Density (g / cm) 3 ) Example 10.652550.732302.985:151350.34 Example 20.652550.732302.980:201350.34 Example 30.652550.732302.975:251350.34 Example 40.652550.712302.985:151350.34 Comparative Example 10.652550.732302.980:201350.34 Comparative Example 20.652550.732302.960:40--Comparative Example 30.652550.732302.990:101350.34 Comparative Example 40.652550.602302.975:25--Comparative Example 50.652550.672302.975:251350.34

[0161]

[0162] Exam example

[0163] (1) Intrinsic viscosity

[0164] 2.0±0.0001 g of the polyester sample used in the above examples and comparative examples was weighed and placed in an Erlenmeyer flask with a stopper, and 25 ml of an organic solvent (ortho-chlorophenol) was added thereto. The flask was placed in a dissolution bath (100°C) and stirred for 1 hour to dissolve the sample in the organic solvent, and then cooled in a constant temperature bath (25±0.5°C) for 20 minutes.

[0165] 7.5 ml of the sample solution was taken from the flask above, placed in a viscometer (CANNON CAV; manufactured by Cannon Instrument; Compliance with ASTM D445 / 446), and the intrinsic viscosity of the sample was measured after incubation at 25±0.5℃ for 20 minutes.

[0166]

[0167] (2) Lecture (mgf)

[0168] Specimens (1 inch x 2.5 inches) of spunbond nonwoven fabrics according to the above examples and comparative examples were prepared. The stiffness (mgf) of the specimens in the longitudinal (MD) direction was measured using a stiffness tester (Gurley type stiffness tester, 4171D) according to the standard test method of JIS L 1913:2010.

[0169]

[0170] (3) Air permeability (cm) 3 / cm 2 / sec)

[0171] The air permeability of spunbond nonwoven fabrics was measured under a pressure of 125 Pa using an air permeability meter (FX 3300 LabAir IV, TEXTEST INSTRUMENTS) according to the standard test method of ASTM D737-18 (2023).

[0172]

[0173] (4) Evaluation of operability and quality

[0174] If defects occur on the nonwoven fabric due to clumping, cutting, or dropping of filaments during the manufacturing process of spunbond nonwoven fabric, the workability and quality are evaluated as ‘poor.’

[0175]

[0176] Strength (mgf)Air permeability (cm) 3 / cm 2 / sec)Operability and quality Example 1106776Good Example 2115672Good Example 3124569Good Example 4102279Good Comparative Example 171165Good Comparative Example 2--Poor Comparative Example 391871Good Comparative Example 4--Poor Comparative Example 596474Poor

[0177]

[0178] Referring to Tables 1 and 2 above, the spunbond nonwoven fabrics of the examples have a strength of 1022 mgf or more and a modulus of 69 cm while having a weight per unit area and an apparent density equivalent to those of the comparative examples. 3 / cm 2 It showed an air permeability of more than / sec, and was confirmed to have good operability and quality.

[0179] The spunbond nonwoven fabric of Comparative Example 1 used raw materials having the same composition as Example 2, but it was confirmed that it exhibited significantly lower stiffness and lower air permeability than Example 2 because the first and second polyester filaments were applied in a mixed form.

[0180] In Comparative Example 2, as the content of the second polyester was too high, cooling and stretching could not be performed properly during the spinning process, and ultimately, a nonwoven fabric could not be manufactured.

[0181] It was confirmed that the spunbond nonwoven fabric of Comparative Example 3 had lower strength and air permeability than the examples due to the content of the second polyester being too low.

[0182] In Comparative Example 4, since a second polyester having an inherent viscosity that was too low was applied, a phenomenon of bending of the filaments during the spinning process was observed, the quality was poor due to drops, and the pressure of the spinning pack was not sufficiently secured, so filaments of a uniform shape could not be formed, and ultimately, a nonwoven fabric could not be manufactured.

[0183] In Comparative Example 5, a spunbond nonwoven fabric could be manufactured, but a warping phenomenon was observed during the spinning process, and the pressure of the spinning pack was not sufficiently secured, so filaments of a uniform shape could not be formed.

[0184]

[0185] Although the present invention has been described above through limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. Comprising a fiber web including core-in-sheath type filaments, The core-in-cis type long fiber comprises a core portion including a first polyester having a melting point of 250° C. or higher and a sheath portion including a second polyester having a melting point of 160° C. to 235° C. The core-in-sheath type long fiber comprises the core portion and the sheath portion in a weight ratio of 65:35 to 85:15, The second polyester has an intrinsic viscosity (IV) that is 0.05 dl / g to 0.1 dl / g higher than that of the first polyester. Spunbond nonwoven fabric for filters.

2. In paragraph 1, The above first polyester has an inherent viscosity of 0.65 dl / g to 0.75 dl / g, The second polyester has an inherent viscosity of 0.70 dl / g to 0.85 dl / g. Spunbond nonwoven fabric for filters.

3. In paragraph 1, A spunbond nonwoven fabric for a filter, wherein the core-in-sheath type long fibers have a fineness of 2 to 5 denier.

4. In paragraph 1, The above spunbond nonwoven fabric is 0.30 g / cm 3 0.38 g / cm 3 A spunbond nonwoven fabric for filters having an apparent density of 100.

5. In paragraph 1, The above spunbond nonwoven fabric is 130 g / m 2 170 g / m 2 A spunbond nonwoven fabric for filters, having a weight per unit area of:

6. In paragraph 1, The above spunbond nonwoven fabric is a spunbond nonwoven fabric for filters having a stiffness of 1000 mgf or more.

7. In paragraph 1, The above spunbond nonwoven fabric is 30 cm in length according to the standard test method of ASTM D737-18 (2023). 3 / cm 2 A spunbond nonwoven fabric for filters having an air permeability of more than / sec.

8. In paragraph 1, The above spunbond nonwoven fabric is 135±5 g / m 2 Tensile strength of 1000 to 1300 mgf per unit area and tensile strength of 30 to 85 cm 3 / cm 2 A spunbond nonwoven fabric having an air permeability of / sec. A step of obtaining a core-in-sheath type filament including a core portion including the first polyester and a sheath portion including the second polyester by composite spinning of a first polyester having a melting point of 9.250° C. or higher and a second polyester having a melting point of 160° C. to 235° C., A step of forming a fiber web by laminating the core-in-sheath type long fibers on a net conveyor, and Comprising a step of heat treating the above fiber web under pressure to form a spunbond nonwoven fabric; The core-in-sheath type long fiber comprises the core portion and the sheath portion in a weight ratio of 65:35 to 85:15, The second polyester has an intrinsic viscosity (IV) that is 0.05 dl / g to 0.1 dl / g higher than that of the first polyester. A method for manufacturing a spunbond nonwoven fabric for a filter according to claim 1.

10. In paragraph 9, A method for producing a spunbond nonwoven fabric for a filter, wherein the step of obtaining the core-in-sheath type long fiber is performed at a spinning speed of 4000 m / min to 6000 m / min.

11. In paragraph 9, A method for producing a spunbond nonwoven fabric for a filter, wherein the above heat treatment is performed at a temperature of 100°C to 200°C.