Core-sheath type composite fiber, non-woven fabric, and article

Abstract

Disclosed are a core-sheath type composite fiber, a non-woven fabric, and an article. The disclosed core-sheath type composite fiber comprises: a core part containing a first polypropylene-based polymer having a melting point (Tm1) of 145-165°C, as measured according to ASTM D3418; and a sheath part containing a second polypropylene-based polymer having a melting point (Tm2) of 120-140°C, as measured according to ASTM D3418.

Description

Core-type composite fibers, nonwoven fabrics and articles

[0001] Disclosed are core-type composite fibers, nonwoven fabrics, and articles. More specifically, core-type composite fibers, nonwoven fabrics, and articles having excellent strength and breathability are disclosed.

[0002] Nonwoven fabrics are used for a variety of purposes, including industrial applications such as medical, protective clothing and masks, and sanitary products such as diapers and sanitary pads.

[0003] Furthermore, nonwoven fabrics are typically manufactured and used in multilayer structures, with two or more layers bonded together. For most applications, superior strength is required. Therefore, many researchers are focusing on developing multilayer nonwoven fabrics with superior strength.

[0004] In addition, in pursuit of weight reduction of existing nonwoven fabrics in line with recent trends, there were limitations in the process and equipment in maintaining the properties of existing nonwoven fabrics or further improving the properties of nonwoven fabrics.

[0005] Meanwhile, since the air-through nonwoven fabric is a nonwoven fabric composed of hard, high-denier fibers with high bonding strength and excellent bending rigidity characteristics, there are limitations in replacing the air-through nonwoven fabric with a conventional spunbond nonwoven fabric.

[0006] One embodiment of the present invention provides a core-type composite fiber having excellent strength and breathability.

[0007] Another embodiment of the present invention provides a nonwoven fabric comprising the above-described core-type composite fiber.

[0008] Another embodiment of the present invention provides an article comprising the nonwoven fabric.

[0009] One aspect of the present invention is:

[0010] A core comprising a first polypropylene polymer having a melting point (Tm1) of 145 to 165°C as measured according to ASTM D3418; and

[0011] A core-sheath composite fiber is provided, which includes a first portion comprising a second polypropylene polymer having a melting point (Tm2) of 120 to 140°C as measured according to ASTM D3418.

[0012] The first polypropylene polymer may have a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 32 to 70 g / 10 min as measured according to ASTM D1238, and the second polypropylene polymer may have a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 10 to 27 g / 10 min as measured according to ASTM D1238.

[0013] The weight ratio of the above-mentioned superficial portion to the above-mentioned deep portion may be 1 to 5:9 to 5.

[0014] Another aspect of the present invention is:

[0015] A nonwoven fabric including the above-mentioned core-type composite fiber is provided.

[0016] The above nonwoven fabric is measured according to NWSP 90.1 (KS K 9073-7), and may have a strength per basis weight (Cantilever) expressed by the following mathematical formula 1 of 1.0 mm / gsm or more in the MD direction or 0.7 mm / gsm or more in the CD direction:

[0017] [Mathematical Formula 1]

[0018] Strength per basis weight (mm / gsm) = Strength (mm) / basis weight (gsm).

[0019] The above nonwoven fabric is measured according to NWSP 90.1 (KS K 9073-7), and the cantilever per unit thickness, expressed by the following mathematical formula 2, may be 150 to 300 in the MD direction or 100 to 250 in the CD direction:

[0020] [Equation 2]

[0021] Strength per unit thickness = Strength (mm) / Unit thickness (mm).

[0022] The above nonwoven fabric is measured according to NWSP 110.4 (Strip Tensile), and the sum of the MD direction elastic modulus per basis weight and the CD direction elastic modulus per basis weight, expressed by the following mathematical formula 3, may be 0.09 N·% / (5 cm·gsm) or more:

[0023] [Equation 3]

[0024] Elastic modulus per basis weight = Elastic modulus (N·% / 5cm) / basic weight (gsm),

[0025] In the above mathematical expression 3, the elastic modulus is expressed by the following mathematical expression 4:

[0026] [Equation 4]

[0027] Elastic modulus = tensile strength (N / 5cm) / tensile elongation (%).

[0028] The above nonwoven fabric may be a spunbond nonwoven fabric.

[0029] The above nonwoven fabric may be composed of two or more layers.

[0030] Another aspect of the present invention is:

[0031] An article including the above nonwoven fabric is provided.

[0032] The above article may include a support for a filter or a filter.

[0033] A nonwoven fabric and an article comprising the same according to one embodiment of the present invention have the advantages of excellent strength and breathability.

[0034] Figure 1 is a cross-sectional view of a core-type composite fiber constituting a nonwoven fabric according to one embodiment of the present invention.

[0035] Figure 2 is a cross-sectional view of a side-by-side composite fiber constituting a nonwoven fabric according to Comparative Examples 11 to 12.

[0036] Hereinafter, a core-type composite fiber according to one embodiment of the present invention will be described in detail.

[0037] In this specification, "NWSP" is an abbreviation for "Nonwovens Standard Procedures" and provides methods for testing the structure and performance of nonwovens and related materials.

[0038] Also, in this specification, gsm, the unit of “basic weight”, is g / m 2 is an abbreviation for .

[0039] A core-type composite fiber according to one embodiment of the present invention includes a core and a sheath.

[0040] The core may include a first polypropylene polymer having a melting point (Tm1) of 145 to 165°C as measured according to ASTM D3418.

[0041] The above first polypropylene polymer may have a melt flow rate (MFR: measurement temperature 230°C, load 2.16 kg) of 32 to 70 g / 10 min measured according to ASTM D1238.

[0042] The above-mentioned first polymer may include a second polypropylene polymer having a melting point (Tm2) of 120 to 140°C as measured according to ASTM D3418.

[0043] The above second polypropylene polymer may have a melt flow rate (MFR: measurement temperature 230°C, load 2.16 kg) of 10 to 27 g / 10 min measured according to ASTM D1238.

[0044] The first propylene polymer and the second propylene polymer may each independently include a propylene homopolymer, a propylene-ethylene random copolymer, an elastomeric random copolymer in which ethylene is copolymerized with polypropylene, a propylene-ethylene-butylene terpolymer, or a combination thereof.

[0045] Specifically, at least one of the first propylene-based polymer and the second propylene-based polymer may include a homopolymer of propylene; a copolymer comprising propylene as a main structural unit component and one or more of α-olefins having 2 to 20 carbon atoms, for example, 2 to 8 carbon atoms, such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene; or a combination thereof.

[0046] The above propylene polymer can be produced using a highly stereoregular polymerization catalyst.

[0047] The above-mentioned high stereoregularity polymerization catalyst may include a catalyst of a diester component, a catalyst of a succinate component, a metallocene catalyst, or a combination thereof.

[0048] The weight ratio of the above-mentioned superficial portion to the above-mentioned deep portion may be 1 to 5:9 to 5.

[0049] When the melting rate of the core, the melting point of the core, the melting rate of the sheath, the melting point of the sheath, and the weight ratio of the sheath to the core are each within the above ranges, a core-sheath composite fiber capable of providing a nonwoven fabric having excellent strength, air permeability, cantilever, and elasticity can be obtained.

[0050] The first polypropylene polymer and the second polypropylene polymer may be manufactured using a highly stereoregular polymerization catalyst.

[0051] The above-mentioned high stereoregularity polymerization catalyst may include a catalyst of a diester component, a catalyst of a succinate component, a metallocene catalyst, or a combination thereof.

[0052] Figure 1 is a cross-sectional view of a core-type composite fiber (100) constituting a nonwoven fabric according to one embodiment of the present invention.

[0053] Referring to FIG. 1, the core-type composite fiber (100) includes a core (110) and a sheath (120) configured to surround the core.

[0054] Another aspect of the present invention provides a nonwoven fabric comprising the above-described core-type composite fiber.

[0055] The above nonwoven fabric is measured according to NWSP 90.1 (KS K 9073-7), and may have a strength per basis weight (Cantilever) expressed by the following mathematical formula 1 of 1.0 mm / gsm or more in the MD direction or 0.7 mm / gsm or more in the CD direction:

[0056] [Mathematical Formula 1]

[0057] Strength per basis weight (mm / gsm) = Strength (mm) / basis weight (gsm).

[0058] In addition, the nonwoven fabric may have a cantilever strength per unit thickness of 150 to 300 in the MD direction or 100 to 250 in the CD direction, as measured according to NWSP 90.1 (KS K 9073-7) and expressed by the following mathematical formula 2:

[0059] [Equation 2]

[0060] Strength per unit thickness = Strength (mm) / Unit thickness (mm).

[0061] In addition, the nonwoven fabric may have a sum of the modulus of elasticity in the MD direction per basis weight and the modulus of elasticity in the CD direction per basis weight, as measured according to NWSP 110.4 (Strip Tensile), expressed by the following mathematical formula 3, of 0.09 N·% / (5 cm·gsm) or more:

[0062] [Equation 3]

[0063] Elastic modulus per basis weight = Elastic modulus (N·% / 5cm) / basic weight (gsm),

[0064] In the above mathematical expression 3, the elastic modulus is expressed by the following mathematical expression 4:

[0065] [Equation 4]

[0066] Elastic modulus = tensile strength (N / 5cm) / tensile elongation (%).

[0067] The above nonwoven fabric may be a spunbond nonwoven fabric.

[0068] The above nonwoven fabric may be composed of two or more layers. For example, the above nonwoven fabric may be a nonwoven laminate.

[0069] The fineness of the above nonwoven fabric may be 4 denier or more.

[0070] The basic weight of the above nonwoven fabric is 15 to 100 g / m 2 , for example, 7~30 g / m 2 It could be.

[0071] The above-mentioned core-type composite fiber may further include additives as needed, in addition to the first polypropylene-based polymer and the second polypropylene-based polymer, within a range that does not impair the purpose of the present invention. The additives may include known softeners, heat stabilizers, weather stabilizers, various stabilizers, antistatic agents, antiblocking agents, anticlouding agents, fillers, dyes, pigments, natural oils, synthetic oils, waxes, or combinations thereof.

[0072] The above softener may include an erucamide-based softener, a wax emulsion, a reactive softener, a silicone-based softener, a surfactant, an ester compound, an ethylene bis stearamide-based softener, an ethylene-propylene random copolymer, an ethylene-butene-propylene copolymer, or a combination thereof.

[0073] Additionally, the above-mentioned softener can be used in the form of a master batch chip manufactured by melt-mixing it with a polymer such as polypropylene.

[0074] In addition, the content of the softener (i.e., the softener component excluding the polymer in the master batch chip) may be 0.1 to 30 parts by weight with respect to 100 parts by weight of the nonwoven fabric.

[0075] The above stabilizers include anti-aging agents such as 2,6-di-t-butyl-4-methylphenol (BHT); phenolic antioxidants such as tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate]methane, β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid alkyl ester, and 2,2'-oxamidobis[ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate; fatty acid metal salts such as zinc stearate, calcium stearate, and calcium 1,2-hydroxystearate; polyhydric alcohol fatty acid esters such as glycerin monostearate, glycerin distearate, pentaerythritol monostearate, pentaerythritol distearate, and pentaerythritol tristearate; or a combination thereof.

[0076] The filler may include silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, talc, clay, mica, asbestos, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder, molybdenum sulfide, or a combination thereof.

[0077] The above-described propylene polymer and the additives used as needed can be mixed using a known method.

[0078] Hereinafter, a method for manufacturing a nonwoven fabric according to one embodiment of the present invention will be described in detail.

[0079] A method for manufacturing a nonwoven fabric according to one embodiment of the present invention includes a step (S10) of melting a core-forming polymer and a sheath-forming polymer using separate extruders to form a core-forming melt and a sheath-forming melt, a step (S20) of discharging each of the melts through a spinneret having a composite spinning nozzle configured to form a desired fiber structure and discharging the melt to emit composite fibers, a step (S30) of cooling and drawing the released composite fibers, and a step (S40) of collecting the cooled and drawn composite fibers on a collecting belt and depositing them at a predetermined thickness to form a nonwoven fabric.

[0080] In the above step (10), one or more additives may be added to at least one of the polymer for forming the core and the polymer for forming the first layer.

[0081] In the above step (S20), the temperature of the spinneret can be maintained at 230 to 250°C. If the temperature of the spinneret is within the above range in the above step (S20), good process stability (spinnability) can be obtained in the nonwoven fabric manufacturing process.

[0082] The above step (S30) may be a step of cooling the composite fiber released in the above step (S20) by cooling air and also applying tension by drawing air to give it a predetermined fineness.

[0083] In addition, the method for manufacturing the nonwoven fabric may further include a step (S50) of imparting mechanical properties to the nonwoven fabric formed in the step (S40).

[0084] The above step (S50) can be performed by a method using a needle punch, water jet, ultrasonic wave, etc. as a bridging process, an embossing process using a heated embossing roll, or a method of heat-sealing by high-temperature ventilation.

[0085] Hereinafter, an article according to one embodiment of the present invention will be described in detail.

[0086] An article according to one embodiment of the present invention comprises the nonwoven fabric described above.

[0087] The above article may include a support for a filter or a filter, but the present invention is not limited thereto.

[0088] Hereinafter, the present invention will be described in more detail through examples. These examples are intended to explain the present invention more specifically, and the scope of the present invention is not limited to these examples.

[0089] Example 1: Preparation of core-type composite fibers and nonwoven fabrics

[0090] A nonwoven fabric composed of a core-type composite fiber (100) having the structure of Fig. 1 was manufactured by the following method. Specifically, 70 parts by weight of a first polypropylene-based polymer for core-forming (i.e., a first propylene homopolymer) having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured according to ASTM D1238 and 30 parts by weight of a second polypropylene-based polymer for sheath-forming (i.e., a second propylene homopolymer) having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured according to ASTM D1238 were each melted using separate extruders to form a core-forming melt and a sheath-forming melt. Thereafter, each of the above melts was extruded through a spinneret having a composite spinning nozzle. Thereafter, each of the ejected melts was cooled by cooling air and tension was applied by drawing air to obtain a predetermined fineness. Thereafter, the cooled and drawn core-shaped composite fibers were collected on a collecting belt and deposited to a predetermined thickness to form a nonwoven fabric. Thereafter, mechanical properties were imparted to the formed nonwoven fabric by embossing using a heated embossing roll. As a result, a nonwoven fabric was obtained.

[0091] Example 2: Preparation of core-type composite fibers and nonwoven fabrics

[0092] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 32 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238.

[0093] Example 3: Preparation of core-type composite fibers and nonwoven fabrics

[0094] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 70 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238.

[0095] Example 4: Preparation of core-type composite fibers and nonwoven fabrics

[0096] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 145°C, as measured according to ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured according to ASTM D1238.

[0097] Example 5: Preparation of core-type composite fibers and nonwoven fabrics

[0098] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 165°C, as measured according to ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured according to ASTM D1238.

[0099] Example 6: Preparation of core-type composite fibers and nonwoven fabrics

[0100] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 10 g / 10 min and a melting point (Tm) of 130°C, as measured in accordance with ASTM D1238, was used instead of the second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C, as measured in accordance with ASTM D1238, was used.

[0101] Example 7: Preparation of core-type composite fibers and nonwoven fabrics

[0102] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 27 g / 10 min as measured in accordance with ASTM D1238 and a melting point (Tm) of 130°C was used instead of the second polypropylene polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min as measured in accordance with ASTM D1238 and a melting point (Tm) of 130°C.

[0103] Example 8: Preparation of core-type composite fibers and nonwoven fabrics

[0104] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 120°C, as measured according to ASTM D1238, was used instead of the second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C, as measured according to ASTM D1238, was used.

[0105] Example 9: Preparation of core-type composite fibers and nonwoven fabrics

[0106] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 140°C, as measured according to ASTM D1238, was used instead of the second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C, as measured according to ASTM D1238, was used.

[0107] Example 10: Preparation of core-type composite fibers and nonwoven fabrics

[0108] Instead of using 30 parts by weight of a first polypropylene polymer for core formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured in accordance with ASTM D1238 and 70 parts by weight of a second polypropylene polymer for sheath formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured in accordance with ASTM D1238, 90 parts by weight of a first polypropylene polymer for core formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured in accordance with ASTM D1238 and 70 parts by weight of a second polypropylene polymer for sheath formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured in accordance with ASTM D1238, A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that 10 parts by weight of a second polypropylene polymer for forming a core having a melting point (Tm) of 130°C, a measured temperature of 230°C, a load of 2.16 kg, and a melting point (Tm) of 18.5 g / 10 min was used.

[0109] Example 11: Preparation of core-type composite fibers and nonwoven fabrics

[0110] Instead of using 30 parts by weight of a first polypropylene-based polymer for core formation having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured according to ASTM D1238 and 70 parts by weight of a second polypropylene-based polymer for sheath formation having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured according to ASTM D1238, 50 parts by weight of a first polypropylene-based polymer for core formation having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured according to ASTM D1238 and 70 parts by weight of a second polypropylene-based polymer for sheath formation having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured according to ASTM D1238, A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that 50 parts by weight of a second polypropylene polymer for forming a core having a melting point (Tm) of 130°C, a measured temperature of 230°C, a load of 2.16 kg, and a melting point (Tm) of 18.5 g / 10 min was used.

[0111] Comparative Example 1: Production of core-type composite fibers and nonwoven fabrics

[0112] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 28 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238.

[0113] Comparative Example 2: Production of core-type composite fibers and nonwoven fabrics

[0114] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 74 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured in accordance with ASTM D1238.

[0115] Comparative Example 3: Manufacturing of core-type composite fibers and nonwoven fabrics

[0116] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 140°C, as measured according to ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured according to ASTM D1238.

[0117] Comparative Example 4: Manufacturing of core-type composite fibers and nonwoven fabrics

[0118] A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that a core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 170°C, as measured according to ASTM D1238, was used instead of the core-forming first polypropylene polymer having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C, as measured according to ASTM D1238.

[0119] Comparative Example 5: Production of core-type composite fibers and nonwoven fabrics

[0120] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 7 g / 10 min and a melting point (Tm) of 130°C, as measured in accordance with ASTM D1238, was used instead of the second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C, as measured in accordance with ASTM D1238.

[0121] Comparative Example 6: Manufacturing of core-type composite fibers and nonwoven fabrics

[0122] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 30 g / 10 min as measured in accordance with ASTM D1238 and a melting point (Tm) of 130°C was used instead of the second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min as measured in accordance with ASTM D1238 and a melting point (Tm) of 130°C was used.

[0123] Comparative Example 7: Production of core-type composite fibers and nonwoven fabrics

[0124] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 115°C, as measured in accordance with ASTM D1238, was used instead of the second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C, as measured in accordance with ASTM D1238, was used.

[0125] Comparative Example 8: Manufacturing of core-type composite fibers and nonwoven fabrics

[0126] A core-type composite fiber and a nonwoven fabric were manufactured in the same manner as in Example 1, except that a second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 145°C, as measured according to ASTM D1238, was used instead of the second polypropylene-based polymer for forming a sheath having a melt flow rate (MFR: measured at 230°C, load 2.16 kg, as measured according to ASTM D1238) of 18.5 g / 10 min and a melting point (Tm) of 130°C, as measured according to ASTM D1238, was used.

[0127] Comparative Example 9: Manufacturing of core-type composite fibers and nonwoven fabrics

[0128] Instead of using 30 parts by weight of a first polypropylene-based polymer for core formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured according to ASTM D1238 and 70 parts by weight of a second polypropylene-based polymer for sheath formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured according to ASTM D1238, 95 parts by weight of a first polypropylene-based polymer for core formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured according to ASTM D1238 and 70 parts by weight of a second polypropylene-based polymer for sheath formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured according to ASTM D1238, A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that 5 parts by weight of a second polypropylene polymer for forming a core having a melting point (Tm) of 130°C, a measured temperature of 230°C, a load of 2.16 kg, and a melting point (Tm) of 18.5 g / 10 min was used.

[0129] Comparative Example 10: Manufacturing of core-type composite fibers and nonwoven fabrics

[0130] Instead of using 30 parts by weight of a first polypropylene-based polymer for core formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured in accordance with ASTM D1238 and 70 parts by weight of a second polypropylene-based polymer for sheath formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured in accordance with ASTM D1238, 40 parts by weight of a first polypropylene-based polymer for core formation having a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured in accordance with ASTM D1238, A core-type composite fiber and nonwoven fabric were manufactured in the same manner as in Example 1, except that 60 parts by weight of a second polypropylene polymer for forming a core having a melting point (Tm) of 130°C, a measured temperature of 230°C, a load of 2.16 kg, and a melting point (Tm) of 18.5 g / 10 min was used.

[0131] Comparative Example 11: Manufacturing of side-by-side composite fibers and nonwoven fabrics

[0132] A nonwoven fabric composed of side-by-side composite fibers (1) having the structure of Fig. 2 was manufactured by the following method. Specifically, 70 parts by weight of a first polypropylene polymer for forming side A, having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured according to ASTM D1238, and 30 parts by weight of a second polypropylene polymer for forming side B, having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured according to ASTM D1238, were each melted by separate extruders to form a melt for forming side A and a melt for forming side B. Thereafter, each of the above melts was extruded through a spinneret having a composite spinning nozzle. Thereafter, each of the discharged melts was cooled by cooling air and tension was applied by drawing air to obtain a predetermined fineness. Thereafter, the cooled and drawn side-by-side composite fibers were collected on a collecting belt and deposited to a predetermined thickness to form a nonwoven fabric. Thereafter, mechanical properties were imparted to the formed nonwoven fabric by embossing using a heated embossing roll. As a result, a nonwoven fabric was obtained.

[0133] Comparative Example 12: Manufacturing of side-by-side composite fibers and nonwoven fabrics

[0134] Instead of using 70 parts by weight of a first polypropylene-based polymer for forming side A having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 51 g / 10 min and a melting point (Tm) of 155°C as measured in accordance with ASTM D1238 and 30 parts by weight of a second polypropylene-based polymer for forming side B having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 18.5 g / 10 min and a melting point (Tm) of 130°C as measured in accordance with ASTM D1238, 50 parts by weight of a first polypropylene-based polymer for forming side A having a melt flow rate (MFR: measured at 230°C, load 2.16 kg) of 60 g / 10 min and a melting point (Tm) of 160°C as measured in accordance with ASTM D1238 and a melt flow rate (MFR: Side-by-side composite fibers and nonwoven fabrics were manufactured in the same manner as in Comparative Example 11, except that 50 parts by weight of a second polypropylene polymer for forming side B, having a melting point (Tm) of 130°C, a measurement temperature of 230°C, a load of 2.16 kg, and a melting point (Tm) of 20 g / 10 min, was used.

[0135] In the above Examples 1 to 11 and Comparative Examples 1 to 12, the MFR of the first polypropylene-based polymer (PP1) for forming the core or side A, the MFR of the second polypropylene-based polymer (PP2) for forming the first part or side B, and the weight ratio of the first part (side B) and the core (side A) are shown in Table 1 below.

[0136] Example 12345 Core MFR (g / 10min) 5132705151 Core melting point (℃) 155155155145165 Initial MFR (g / 10min) 18.518.518.518.518.5 Initial melting point (℃) 130130130130130 Initial: Core weight ratio 3:73:73:73:73:7 Example 678910 Core MFR (g / 10min) 5151515151 Core melting point (℃) 155155155155155 Initial MFR (g / 10min) 102718.518.518.5 Initial melting point (℃) 130130120140130 Initial: Core Weight ratio 3:73:73:73:71:9Example 111234Core MFR (g / 10min) 5128745151Core melting point (℃) 155155155140170Initial MFR (g / 10min) 18.518.518.518.518.518.5Initial melting point (℃) 130130130130130Initial:Core Weight ratio 5:53:73:73:73:7 Denier of core-sheath composite fiber 4.74.84.84.74.9 Thickness of nonwoven fabric (mm) 0.360.320.350.330.34Comparative example 5678910Core MFR (g / 10min) 515151515151Core Melting point (℃) 155 155 155 155 155 155 Initial MFR (g / 10min) 730 18.5 18.5 18.5 18.5 Initial melting point (℃) 130 130 115 145 130 130 Initial:core weight ratio 3:73:73:73:70.5:9.5 6:4 Comparative example 1112 MFR (g / 10min) 51:18.5 (Side A:Side B) 60:20 (Side A:Side B) Melting point (℃) 155:130 (Side A:Side B) 160:130 (Side A:Side B) Initial:core weight ratio 7:3 (Side A:Side B) 5:5 (Side A:Side B)

[0137]

[0138] Evaluation example: Evaluation of physical properties of nonwoven fabric

[0139] The physical properties of each nonwoven fabric manufactured in Examples 1 to 11 and Comparative Examples 1 to 12 were evaluated using the following method, and the results are shown in Table 2 below.

[0140] (1) Melting point (℃): Melting point was measured using DISCOVERY DSC according to ASTM D3418.

[0141] (2) Thickness (mm): The thickness was measured using a thickness measuring device (MITUTOYO (Japan), DIGITAL GAUGE, 547-301 MODEL) while applying a load of 1.5 N or less to the nonwoven fabric in accordance with the KS K 9073-2 test method. The thickness was measured at 21 locations on the nonwoven fabric, and the average value was taken as the thickness.

[0142] (3) Basic weight (gsm): Measured according to ASTM D 3776-1985.

[0143] (4) Denier evaluation: Using a SEM measuring device, the average value after 40 analyses was recorded as the denier (denier). The denier was measured separately for the fine-fiber nonwoven layer and the crimped nonwoven layer.

[0144] (5) Tensile strength: Using a tensile strength tester (Instron) measuring equipment, a tensile test was performed according to the KSK 0520 method under the conditions of a specimen width of 5 cm, spacing of 10 cm, and a tensile speed of 500 mm / min to obtain the maximum tensile load.

[0145] (6) Tensile elongation: The elongation at maximum elongation was obtained by measuring it using the method (4) above.

[0146] (7) Cantilever: Measured according to NWSP 90.1 (KS K 9073-7).

[0147] (8) Elastic modulus: Measured according to NWSP 110.4 (Strip Tensile).

[0148] (9) Air permeability: Using the FX3300 air permeability meter, the sample was installed in the meter according to the KSK 0507 method, and the air permeability (air permeability) was measured under the measurement area and measurement pressure. The unit of air permeability is ccs (cm 3 / cm 2 / sec).

[0149] Example 12345 Basis weight of nonwoven fabric (gsm) 5555555555 Denier of core-sheath composite fiber 4.9 5.05.04.95.1 Thickness of nonwoven fabric (mm) 0.34 0.35 0.34 0.35 0.36 Tensile strength in MD direction of nonwoven fabric (N / 5cm) 116.6 119.01 14.2 117.7 12 0.9 Tensile strength in CD direction of nonwoven fabric (N / 5cm) 90.2 9 2.0 8 8.39 1.0 9 3.5 Tensile elongation in MD direction of nonwoven fabric (%) 3334313435 Tensile elongation in CD direction of nonwoven fabric (%) 3738363839 Stiffness in MD direction of nonwoven fabric (mm) 7577747876 Tensile strength in CD direction of nonwoven fabric Stiffness (mm) 5354525553 Air permeability (ccs) of nonwoven fabric 270276265279272 Stiffness in MD direction per basic weight of nonwoven fabric (mm / gsm) 1.41.41.31.41.4 Stiffness in CD direction per basic weight of nonwoven fabric (mm / gsm) 1.01.00.91.01.0 Stiffness in MD direction per unit thickness of nonwoven fabric (mm / mm) 221.9220.0217.4225.1213.1 Stiffness in CD direction per unit thickness of nonwoven fabric (mm / mm) 155.6154.3152.5157.9149.4 Elasticity modulus in MD direction of nonwoven fabric (N·% / 5cm) 3.533.503.693.463.45 CD direction of nonwoven fabric Elasticity modulus (N·% / 5cm) 2.44 2.42 2.42 2.42 2.42 Elasticity modulus in MD+CD direction of nonwoven fabric (N·% / 5cm) 5.97 5.92 6.11 5.88 5.88 Elasticity modulus in MD+CD direction per basis weight of nonwoven fabric (N·% / 5cm·gsm) 0.109 0.108 0.11 10.107 0.107 Example 67 89 10 Basic weight of nonwoven fabric (gsm) 5 5 5 5 5 5 5 5 5 5 5 5 Denier of core-sheath composite fiber 5.0 5.0 4.8 5.2 5.4 Thickness of nonwoven fabric (mm) 0.35 0.35 0.34 0.36 0.36 MD direction of nonwoven fabric Tensile strength (N / 5cm)115.4120.2114.2123.8126.2 CD direction tensile strength of nonwoven fabric (N / 5cm)89.292.988.395.797.6 MD direction tensile elongation of nonwoven fabric (%) 35 34 32 35 34 CD direction tensile elongation of nonwoven fabric (%) 37 38 36 40 40 MD direction stiffness of nonwoven fabric (mm) 75 79 80 74 75 CD direction stiffness of nonwoven fabric (mm) 53 55 56 52 52 Air permeability of nonwoven fabric (ccs) 27 0 28 22 8 7 26 5 267 MD ​​direction stiffness per basic weight of nonwoven fabric (mm / gsm) 1.4 1.4 1.5 1.3 1.4 CD direction stiffness per basic weight of nonwoven fabric (mm / gsm) 1.0 1.0 1.0 0.9 1.0 MD direction stiffness per unit thickness of nonwoven fabric (mm / mm) 213.3 22 6.7 23 8.3 203.1 207.3 CD direction stiffness per unit thickness of nonwoven fabric Tensile strength (mm / mm) 149.6 159.0 167.1 142.4 145.4 MD direction elastic modulus of nonwoven fabric (N·% / 5cm) 3.30 3.54 3.57 3.52 3.71 CD direction elastic modulus of nonwoven fabric (N·% / 5cm) 2.4 12.4 2.4 2.39 2.42 MD+CD direction elastic modulus of nonwoven fabric (N·% / 5cm) 5.7 15.9 65.9 95.9 16.13 MD+CD direction elastic modulus per basic weight of nonwoven fabric (N·% / 5cm·gsm) 0.10 4 0.10 8 0.10 9 0.10 7 0.11 2 Preliminary comparative example 1 1 1 2 3 4 Basic weight of nonwoven fabric (gsm) 5 ... Denier 4.7 4.8 4.8 4.7 4.9 Thickness of nonwoven fabric (mm) 0.36 0.32 0.35 0.33 0.34 Tensile strength in MD direction of nonwoven fabric (N / 5cm) 122.4 209.118 1.9 19 1.9 19 5.4 Tensile strength in CD direction of nonwoven fabric (N / 5cm) 94.6 123.6 107.5 113.4 115.4 Tensile elongation in MD direction of nonwoven fabric (%) 347 4646769 Tensile elongation in CD direction of nonwoven fabric (%) 397 3626670 Tensile strength in MD direction of nonwoven fabric (mm) 77 49 425 253 Tensile strength in CD direction of nonwoven fabric (mm) 54 3329 3536 Air permeability (ccs) of nonwoven fabric 275 23220 2247 251 Tensile strength in CD direction of nonwoven fabric Tensile modulus in MD direction per basis weight (mm / gsm)1.40.90.80.91.0Tensile modulus in CD direction per basis weight of nonwoven fabric (mm / gsm)1.00.60.50.60.6Tensile modulus in MD direction per unit thickness of nonwoven fabric (mm / mm)213.5152.6121.4157.1155.3Stiffness per unit thickness of nonwoven fabric in CD direction (mm / mm) 149.7 10 2.88 1.8 10 5.8 10 4.6Elastic modulus in MD direction of nonwoven fabric (N·% / 5cm) 3.60 2.83 2.84 2.86 2.83Elastic modulus in CD direction of nonwoven fabric (N·% / 5cm) 2.43 1.69 1.73 1.72 1.65Elastic modulus in MD+CD direction of nonwoven fabric (N·% / 5cm) 6.03 4.52 4.58 4.58 4.48Elastic modulus per basic weight of nonwoven fabric in MD+CD direction (N·% / 5cm·gsm) 0.110 0.08 20.08 30.08 30.08 1Comparative example 56789 10Basic weight of nonwoven fabric (gsm) 5555555555555Core-sheath type Denier of composite fiber 5.25.04.84.94.84.9Thickness of nonwoven fabric (mm) 0.340.350.350.340.340.34Tensile strength in MD direction of nonwoven fabric (N / 5cm) 201.5209.6186.7198.0190.1194.0Tensile strength in CD direction of nonwoven fabric (N / 5cm) 119.1123.8110.3117.0112.3114.7Tensile elongation in MD direction of nonwoven fabric (%) 777466706769Tensile elongation in CD direction of nonwoven fabric (%) 697267706865Stiffness in MD direction of nonwoven fabric (mm) 494954494952Tensile strength in CD direction of nonwoven fabric Stiffness (mm) 333336333335 Air permeability (ccs) of nonwoven fabric 234232256233235249 Stiffness in MD direction per basis weight of nonwoven fabric (mm / gsm) 0.90.91.00.90.91.0 Stiffness in CD direction per basis weight of nonwoven fabric (mm / gsm) 0.60.60.70.60.60.6 Stiffness in MD direction per unit thickness of nonwoven fabric (mm / mm) 144.9139.3154.0144.1145.6154.2 Stiffness in CD direction per unit thickness of nonwoven fabric (mm / mm) 97.693.8103.797.198.0103.9 MD direction of nonwoven fabric Elasticity modulus (N·% / 5cm)2.622.832.832.832.832.832.83 Elasticity modulus in CD direction of nonwoven fabric (N·% / 5cm)1.721.721.651.671.651.76 Elasticity modulus in MD+CD direction of nonwoven fabric (N·% / 5cm)4.344.554.484.504.484.59 Elasticity modulus in MD+CD direction per basis weight of nonwoven fabric (N·% / 5cm·gsm)0.0790.0830.0810.0820.0810.084Comparative Example 1112Basic weight of nonwoven fabric (gsm) 5555Denier of core-sheath composite fiber 4.84.9Thickness of nonwoven fabric (mm) 0.330.35Tensile strength in MD direction of nonwoven fabric (N / 5cm) 188.2197.6Tensile strength in CD direction of nonwoven fabric (N / 5cm) 111.2116.8Tensile elongation in MD direction of nonwoven fabric (%) 6670Tensile elongation in CD direction of nonwoven fabric (%) 6669Tenderness in MD direction of nonwoven fabric (mm) 4443Tenderness in CD direction of nonwoven fabric (mm) 3029Air permeability (ccs) 209203Tenderness in MD direction per basic weight of nonwoven fabric (mm / gsm) 0.80.8Nonwoven fabric Tensile strength in CD direction per basis weight (mm / gsm)0.50.5Tensile strength in MD direction per unit thickness of nonwoven fabric (mm / mm)133.2121.8Tensile strength in CD direction per unit thickness of nonwoven fabric (mm / mm)89.782.1Elastic modulus in MD direction of nonwoven fabric (N·% / 5cm)2.852.82Elastic modulus in CD direction of nonwoven fabric (N·% / 5cm)1.691.69Elastic modulus in MD+CD direction of nonwoven fabric (N·% / 5cm)4.544.52Elastic modulus in MD+CD direction of nonwoven fabric (N·% / 5cm·gsm)0.0830.082.

[0150]

[0151] In addition, the required properties of nonwoven fabrics suitable for the purpose of the present invention are shown in Table 3 below.

[0152] Required properties of nonwoven fabric Tensile strength (N / 5cm) MD direction 200 or less CD direction 100 or less Tensile elongation (%) MD direction 70 or less CD direction 70 or less Tensile strength (mm) MD direction 50 or more CD direction 35 or more Tensile strength per basic weight (mm / gsm) MD direction 1.0 or more CD direction 0.7 or more Tensile strength per unit thickness (mm / mm) MD direction 150~300 CD direction 100~250 Elastic modulus (N·% / 5cm) MD direction 3.0 or more CD direction 2.0 or more Elastic modulus per basic weight (N·% / (5cm·gsm)) MD direction 0.055 or more CD direction 0.035 or more MD+CD elastic modulus of nonwoven fabric per basic weight (N·% / 5cm·gsm) 0.09 or more Air permeability (ccs) 250 or more

[0153]

[0154] Referring to Tables 2 and 3 above, the nonwoven fabrics manufactured in Examples 1 to 11 were found to satisfy all of the required properties of MD tensile strength, CD tensile strength, MD tensile elongation, CD tensile elongation, MD stiffness, CD stiffness, MD stiffness per basis weight, CD stiffness per basis weight, MD stiffness per unit thickness, CD stiffness per unit thickness, MD modulus of elasticity, CD modulus of elasticity, MD modulus of elasticity per basis weight, CD modulus of elasticity per basis weight, sum of MD modulus of elasticity per basis weight and CD modulus of elasticity per basis weight, and air permeability.

[0155] On the other hand, the nonwoven fabrics manufactured in Comparative Examples 1 to 12 were found to not satisfy at least one of the required properties of MD tensile strength, CD tensile strength, MD tensile elongation, CD tensile elongation, MD stiffness, CD stiffness, MD stiffness per basis weight, CD stiffness per basis weight, MD stiffness per unit thickness, CD stiffness per unit thickness, MD modulus of elasticity, CD modulus of elasticity, MD modulus of elasticity per basis weight, CD modulus of elasticity per basis weight, sum of MD modulus of elasticity per basis weight and CD modulus of elasticity per basis weight, and air permeability.

[0156] While the present invention has been described with reference to the drawings and examples, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent implementations are possible. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

[0157] [Explanation of symbols]

[0158] 100: Core-type composite fiber 110: Core

[0159] 120: First part

Claims

1. A core comprising a first polypropylene polymer having a melting point (Tm1) of 145 to 165°C as measured according to ASTM D3418; and A core-sheath composite fiber comprising a first portion comprising a second polypropylene polymer having a melting point (Tm2) of 120 to 140°C as measured according to ASTM D3418.

2. In paragraph 1, The first polypropylene polymer has a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 32 to 70 g / 10 min as measured according to ASTM D1238, and the second polypropylene polymer has a melt flow rate (MFR: measured at a temperature of 230°C, a load of 2.16 kg) of 10 to 27 g / 10 min as measured according to ASTM D1238.

3. In paragraph 1, A core-type composite fiber having a weight ratio of the above-mentioned superstructure to the above-mentioned core structure of 1 to 5:9 to 5.

4. A nonwoven fabric comprising a core-type composite fiber according to any one of paragraphs 1 and 3.

5. In paragraph 4, The above nonwoven fabric is a nonwoven fabric having a strength per basic weight (Cantilever) of 1.0 mm / gsm or more in MD direction or 0.7 mm / gsm or more in CD direction, as measured according to NWSP 90.1 (KS K 9073-7) and expressed by the following mathematical formula 1: [Mathematical Formula 1] Strength per basis weight (mm / gsm) = Strength (mm) / basis weight (gsm).

6. In paragraph 4, The above nonwoven fabric is a nonwoven fabric having a strength per unit thickness (Cantilever) of 150 to 300 in the MD direction or 100 to 250 in the CD direction, as measured according to NWSP 90.1 (KS K 9073-7), as expressed by the following mathematical formula 2: [Equation 2] Strength per unit thickness = Strength (mm) / Unit thickness (mm).

7. In paragraph 4, The above nonwoven fabric is a nonwoven fabric having a sum of the elastic modulus in the MD direction per basis weight and the elastic modulus in the CD direction per basis weight, expressed by the following mathematical formula 3, of 0.09 N·% / (5 cm·gsm) or more, as measured according to NWSP 110.4 (Strip Tensile): [Equation 3] Elastic modulus per basis weight = Elastic modulus (N·% / 5cm) / basic weight (gsm), In the above mathematical expression 3, the elastic modulus is expressed by the following mathematical expression 4: [Equation 4] Elastic modulus = tensile strength (N / 5cm) / tensile elongation (%).

8. In paragraph 4, The above nonwoven fabric is a spunbond nonwoven fabric.

9. In paragraph 4, The above nonwoven fabric is a nonwoven fabric composed of two or more layers.

10. Articles containing nonwoven fabrics according to Article 4.

11. In paragraph 10, The above article is an article including a support for a filter or a filter.

Images