JP7753245B2 - Nonwoven fabric, nonwoven fabric laminate, article, and method for manufacturing nonwoven fabric - Google Patents

Description

The present invention relates to nonwoven fabrics, nonwoven fabric laminates, articles, and methods for manufacturing nonwoven fabrics, and more specifically to nonwoven fabrics, nonwoven fabric laminates, articles, and methods for manufacturing nonwoven fabrics that have improved softness and bulkiness.

The final physical properties of nonwoven fabrics are determined by the method of web formation and bonding.

When manufacturing existing spunbond nonwoven fabrics, webs are formed through single-filament or core-sheath composite spinning. Webs formed in this way have a simple structure without crimps and are bonded by a heated calendar to form thin nonwoven fabrics.

Thin nonwoven fabrics are used for the top sheet and back sheet in diaper manufacturing, but they have the problem of being significantly less bulky and softer than short-fiber air-through nonwoven fabrics, which are made by forming a web through carding and bonding it with hot air.

In addition, the web is not crimped during formation, resulting in reduced bulkiness. During diaper manufacturing, a large area comes into direct contact with the baby's bottom skin. Furthermore, there is no space between the top sheet and the ADL (acquisition distribution layer) during nonwoven fabric lamination, meaning some urine remains on the top sheet during urination, causing sores on the baby's bottom and potentially leading to rashes. Another problem is urine leakage to the outside of the diaper.

One embodiment of the present invention provides a nonwoven fabric with improved softness and bulkiness.

Another embodiment of the present invention provides a nonwoven fabric laminate comprising two or more sheets of the nonwoven fabric.

Another embodiment of the present invention provides an article comprising the nonwoven fabric laminate.

Another embodiment of the present invention provides a method for producing the nonwoven fabric.

One aspect of the present invention is
A nonwoven fabric containing crimped composite fibers,
The crimped composite fiber has a thickness direction cross section including a side A and a side B,
The ratio (Side B/Side A) of the melt flow rate (MFR) of Side A to Side B measured by ASTM D1238 (measurement temperature: 230°C, load: 2.16 kg) is 0.65 to 1.51 ;
The component ratio represented by the side A/the side B (weight ratio) is 50/50 to 70/30,
The nonwoven fabric has a ratio of molecular weight distribution of the side A to the side B (side B/side A) of 0.5 to 1.5.

Side A includes a first propylene-based polymer, and Side B includes a second propylene-based polymer, and the first propylene-based polymer and the second propylene-based polymer have different melting indices and molecular weight distributions.

Side B further includes a third propylene-based polymer, and the second propylene-based polymer and the third propylene-based polymer have different melting indices and molecular weight distributions, and a component ratio (weight ratio) of the third propylene-based polymer to the second propylene-based polymer is 20/80 to 50/50 .

The nonwoven fabric has a thickness of 0.25 mm or more and a crimp count of 20 or more per 10 mm.

The nonwoven fabric also has a coefficient of friction (COF) of 0.60 or less.

The crimped composite fiber can also be a side-by-side or sandwich composite fiber.

The nonwoven fabric may also be a spunbond nonwoven fabric.

Another aspect of the present invention is
The present invention provides a nonwoven fabric laminate having a layer structure of at least two layers, at least one of which is the nonwoven fabric.

The nonwoven fabric is a spunbond nonwoven fabric, and the nonwoven fabric laminate is configured so that the spunbond nonwoven fabric is exposed on only one of the two surface layers.

Yet another aspect of the present invention is
An article is provided that includes the nonwoven laminate.

The article may be a diaper, absorbent article, toilet product, support layer, back sheet, waistband, or top sheet.

Yet another aspect of the present invention is
Step (S10) of melting a polymer for forming Side A and a polymer for forming Side B in separate extruders at a temperature of 180°C to 250°C in separate sections to form a melt for forming Side A and a melt for forming Side B;
(S20) discharging each of the melts through a spinneret having a composite spinning nozzle;
A step (S30) of dividing each of the discharged melts into an upper region and a lower region, and stretching the melts by passing them through a stretching region in which the volume of the upper region is 90% or more of the volume of the lower region;
and discharging each of the drawn melts through a diffuser (S40),
The diffuser has a trapezoidal longitudinal cross section, and the ratio of top width: middle width: bottom width is 1:1.5 or more:2.0 or more.

The method for manufacturing the nonwoven fabric may further include a step (S50) of imparting mechanical properties to the nonwoven fabric formed in step (S40) through an embossing process using a heated embossing roll or a thermal fusion method using high-temperature airflow.

The method for manufacturing the nonwoven fabric further includes the step (S50) of supplying the nonwoven fabric formed in step (S50) to post-processing equipment and imparting a three-dimensional shape to the surface of the nonwoven fabric by deep embossing or corrugating using a processing roll. The processing roll of the post-processing equipment can impart a thickness of 0.3 mm to 0.7 mm to the nonwoven fabric through deep embossing at 10 to 50 holes/inch, or impart a three-dimensional shape to the surface of the nonwoven fabric through corrugation at 2 to 8 ea/inch.

The nonwoven fabric according to one embodiment of the present invention has a fine crimp morphology, exhibits abundant crimp, has excellent shape stability, and has excellent physical qualities, particularly improved softness and bulkiness.

As a result, diapers containing this nonwoven fabric do not irritate the wearer's skin or cause rashes.

1 is a cross-sectional view of a crimped composite fiber forming a nonwoven fabric according to an embodiment of the present invention.

Below, a nonwoven fabric according to one embodiment of the present invention will be described in detail.

As used herein, "molecular weight distribution (or polydispersity index)" refers to the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn) measured by gel permeation chromatography (GPC).

In addition, in this specification, "melting point" is a value measured using a differential scanning calorimeter (DSC).

A nonwoven fabric according to one embodiment of the present invention includes crimped composite fibers (hereinafter simply referred to as "composite fibers").

(i) The ratio (Side B/Side A) of the melt flow rate (MFR) between Side A and Side B measured by ASTM D1238 (measurement temperature: 230°C, load: 2.16 kg) is 0.65 to 1.51 , (ii) the component ratio expressed by Side A/Side B (weight ratio) is 50/50 to 70/30, and (iii) the ratio (Side B/Side A) of the molecular weight distribution between Side A and Side B is 0.5 to 1.5.

When Side A and Side B satisfy all of the above conditions (i) to (iii), the composite fiber has crimping properties, and a nonwoven fabric made from the composite fiber can have excellent softness and bulkiness.

Side A and Side B are arranged so as to occupy substantially their respective areas within the cross section of the composite fiber and extend continuously along the longitudinal direction, and at least a portion of Side A and Side B may form at least a portion of the peripheral surface continuously along the longitudinal direction of the composite fiber.

Side A includes a first propylene-based polymer, and Side B includes a second propylene-based polymer, and the first propylene-based polymer and the second propylene-based polymer have different melting indices and molecular weight distributions.

The first propylene-based polymer and the second propylene-based polymer each may contain a propylene homopolymer.

The first propylene-based polymer further contains 1 to 5 wt. % of a nucleating agent in addition to the propylene-based polymer component that is the main component, thereby making the crystallization temperature of the first propylene-based polymer higher than the crystallization temperature of the second propylene-based polymer.

The nucleating agent increases the crystallization temperature of the first propylene-based polymer and differentiates the crystallization temperature of Side A from that of Side B, thereby improving the thickness of the nonwoven fabric through the development of crimp and further improving the softness and bulkiness of the nonwoven fabric.

The nucleating agent may include a particulate additive, a self-assembling nucleating agent, a reactive nucleating agent, or a combination thereof. The particulate additive may include sodium benzoate, titanium dioxide, silica, nanoclay, sodium salt, calcium titanate, a metal oxide, a metal hydroxide, or a combination thereof. The self-assembling nucleating agent may include bis(p-methylbenzylidene)sorbitol, dibenzylidene sorbitol, monobenzylidene sorbitol (MBS), bis(p-methylbenzylidene)sorbitol, a derivative thereof, or a combination thereof. The reactive nucleating agent may include a metal salt, 4-biphenylcarboxylic acid, 4-biphenylmethanol, adipic acid, or a combination thereof.

The melting point of the first propylene polymer and the melting point of the second propylene polymer are each independently in the range of 120 to 175°C.

The first propylene polymer has a molecular weight distribution of 2.0 to 3.0, and the second propylene polymer has a molecular weight distribution of 2.5 to 3.5.

In addition, Side B may further contain a third propylene-based polymer, and the second propylene-based polymer and the third propylene-based polymer may have different melting indices and molecular weight distributions.

The third propylene polymer may also include a propylene homopolymer.

The melting point of the third propylene polymer is also in the range of 120 to 175°C.

The third propylene polymer also has a molecular weight distribution of 4.0 to 5.0.

The component ratio expressed by the third propylene polymer/the second propylene polymer (weight ratio) is 20/80 to 50/50 .

The nonwoven fabric also has a hydrophilic agent impregnation (OPU) of 0.7% or less, which allows the nonwoven fabric to have a rewetability index of 5.0 or less and a water absorption durability of 10 seconds or less.

The hydrophilic agent may include a wax emulsion, a reactive softener, a silicon-based compound, a surfactant, or a combination thereof. The silicon-based compound may include an amino group-containing silicon, an oxyalkylene group-containing silicon, or a combination thereof. The surfactant may include anionic surfactants such as carboxylate-based anionic surfactants, sulfonate-based anionic surfactants, sulfate ester-based anionic surfactants, and phosphate ester-based anionic surfactants (particularly alkyl phosphate ester salts); polyhydric alcohol mono-fatty acid esters such as sorbitan fatty acid esters, diethylene glycol monostearate, diethylene glycol monooleate, glyceryl monostearate, glyceryl monooleate, and propylene glycol monostearate; N-(3-oleyloxy-2-hydroxypropyl)diethanolamine, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan beeswax, polyisoprene, and the like. Nonionic surfactants such as oxyethylene sorbitan sesquistearate, polyoxyethylene monooleate, polyoxyethylene glyceryl monooleate, polyoxyethylene monostearate, polyoxyethylene monolaurate, polyoxyethylene monooleate, polyoxyethylene cetyl ether, and polyoxyethylene lauryl ether; cationic surfactants such as quaternary ammonium salts, amine salts, or amines; amphoteric surfactants such as aliphatic derivatives of secondary or tertiary amines, including carboxy, sulfonate, and sulfate, or aliphatic derivatives of heterocyclic secondary or tertiary amines; or combinations thereof.

Specifically, the hydrophilic agent is also a non-ionic hydrophilic agent.

The nonionic hydrophilic agent may include silicon-based compounds such as amino group-containing silicon and oxyalkylene group-containing silicon; nonionic surfactants such as sorbitan fatty acid esters, polyhydric alcohol mono-fatty acid esters such as diethylene glycol monostearate, diethylene glycol monooleate, glyceryl monostearate, glyceryl monooleate, and propylene glycol monostearate; N-(3-oleyloxy-2-hydroxypropyl)diethanolamine, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitan beeswax, polyoxyethylene sorbitan sesquistearate, polyoxyethylene monooleate, polyoxyethylene glyceryl monooleate, polyoxyethylene monostearate, polyoxyethylene monolaurate, polyoxyethylene monooleate, polyoxyethylene cetyl ether, and polyoxyethylene lauryl ether; or combinations thereof.

More specifically, the nonionic hydrophilic agent also includes a surfactant having a solids content of 90% by weight or more (i.e., a nonionic surfactant).

The average diameter of the composite fibers is also 1 to 50 μm.

The first propylene-based polymer, the second propylene-based polymer, and the third propylene-based polymer can be produced using a highly stereoregular polymerization catalyst.

The highly stereospecific polymerization catalyst may include a diester component catalyst, a succinate component catalyst, a metallocene catalyst, or a combination thereof.

Nonwoven fabrics containing the above-mentioned composite fibers can be obtained using the usual composite melt spinning method without using any special equipment, but they can also be spunbonded nonwoven fabrics produced using the highly productive spunbonding method, for example.

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

A method for producing a nonwoven fabric according to one embodiment of the present invention also includes the following steps:
Step (S10) of melting a polymer for forming Side A and a polymer for forming Side B in separate extruders at a temperature of 180°C to 250°C in separate sections to form a melt for forming Side A and a melt for forming Side B;
Step (S20) of discharging each of the melts through a spinneret having a composite spinning nozzle;
A step of dividing each of the discharged melts into an upper region and a lower region, and passing the upper region through a stretching region in which the volume of the upper region is 90% or more of the volume of the lower region, and stretching the melts (S30); and a step of discharging each of the stretched melts through a diffuser (S40).

In step (S40), the diffuser has a trapezoidal cross section, and the ratio of top width: middle width: bottom width is 1:1.5 or more:2.0 or more. The special configuration of the diffuser can further improve the softness and bulkiness of the final nonwoven fabric.

The method for manufacturing the nonwoven fabric may further include a step (S50) of imparting mechanical properties to the nonwoven fabric formed in step (S40) by embossing using a heated embossing roll or by heat sealing using high-temperature airflow.

For example, the embossing process can be carried out under conditions where the bonding rate (i.e., embossing area rate) is 13% or less and the non-embossing unit area is 0.2 ^mm2 or more, for example, 0.2 to 0.7 ^mm2 . Here, the non-embossing unit area refers to the maximum area of a rectangle inscribed in the embossment in the smallest unit of non-embossing area surrounded on all four sides by embossed areas. By carrying out the embossing process under conditions within this range, a nonwoven fabric with greater bulkiness can be obtained while maintaining the required nonwoven fabric strength.

The bonding rate and non-embossed unit area can also be adjusted by changing the embossing pattern.

As a result of the embossing process, the nonwoven fabric includes embossed and non-embossed areas, and the embossed areas are of an open embossing type and include multiple unit embossing pattern areas arranged in succession at the same or different intervals.

In addition, the area of each embossing pattern included in the unit embossing pattern portion is 0.2 to 0.7 mm ² .

The nonwoven fabric manufacturing method may further include a step (S50) of supplying the nonwoven fabric formed in step (S50) to post-processing equipment and imparting a three-dimensional shape to the surface of the nonwoven fabric by applying a deep embossing or corrugated pattern using a processing roll.

In step (S50), the processing rolls of the post-processing equipment are configured to give the nonwoven fabric a thickness of 0.3 mm to 0.7 mm through deep embossing at 10 to 50 holes/inch, and to give the surface of the nonwoven fabric a three-dimensional shape through wrinkle processing at 2 to 8 ea/inch. The post-processing (particularly perforation) in step (S50) can further improve the softness and bulkiness of the final nonwoven fabric.

The nonwoven fabric may further contain a fatty acid amide having 5 to 25 carbon atoms in an amount of 0.01 to 3 wt % based on the total weight of the nonwoven fabric.

The fatty acid amide can act as a slip agent.

The fatty acid amide may also include oleamide, erucamide, stearamide, or a combination thereof.

The composite fiber may contain other components, as necessary, in addition to the first propylene polymer, the second propylene polymer, and/or the third propylene polymer, to the extent that the objectives of the present invention are not impaired. The other components may include known heat stabilizers, weather stabilizers, various stabilizers, antistatic agents, antiblocking agents, anticlouding agents, fillers, dyes, pigments, natural oils, synthetic oils, waxes, or combinations thereof.

The stabilizer may also include antioxidants 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, beta-(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 combinations thereof.

The filler may also include silica, diatomaceous earth, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloons, 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.

The aforementioned propylene-based polymer and the other components used as needed can be mixed using known methods.

The composite fiber may also be a side-by-side or sandwich type composite fiber.

For example, referring to FIG. 1, composite fiber 1 is also a side-by-side composite fiber whose thickness direction cross section includes side A made of the first propylene-based polymer and side B made of the second propylene-based polymer and/or the third propylene-based polymer.

The nonwoven fabric has a thickness of 0.25 mm or more and a crimp count of 20 or more per 10 mm.

The nonwoven fabric also has a coefficient of friction (COF) of 0.60 or less.

The fineness and basis weight of the nonwoven fabric are appropriately selected depending on the application, but generally, the fineness is 1.0 to 2.5 denier, for example, 0.7 to 2.0 denier, and the basis weight is 15 to 100 g/m ² , for example, 7 to 30 g/m ² .

Below, a nonwoven fabric laminate according to one embodiment of the present invention will be described in detail.

A nonwoven fabric laminate according to one embodiment of the present invention is a laminate having a layer structure of at least two layers, at least one of which is the nonwoven fabric described above.

The nonwoven fabric laminate also includes spunbond nonwoven fabric, one of the nonwoven fabrics mentioned above.

For example, the crimped nonwoven fabric may be a spunbond nonwoven fabric, and the nonwoven fabric laminate may be configured so that the spunbond nonwoven fabric is exposed on only one of the two surface layers.

The nonwoven fabric laminate may also be formed by laminating four sheets of the spunbond nonwoven fabric, and in this case, the nonwoven fabric laminate has a uniformity (CV%) of 3% or less. In this specification, "uniformity (CV%)" refers to the percentage obtained by cutting the nonwoven fabric laminate into 1 ^m2 pieces to make 30 test pieces, and then dividing the weight deviation of the 30 test pieces by the average weight of the plurality of test pieces.

The nonwoven fabric laminate, which is formed by stacking four sheets of the spunbond nonwoven fabric, has a thickness of 0.2 mm or more, a crimp count of 10 or more per 10 mm, a bonding rate of 18% or less, and an MD stiffness, which indicates the softness of the nonwoven fabric laminate, of 50 mm or less. In this specification, "MD stiffness" refers to the bending deformation in the machine direction of the nonwoven fabric laminate (i.e., the degree to which the nonwoven fabric laminate is warped).

An article according to one embodiment of the present invention will now be described in detail.

An article according to one embodiment of the present invention includes the nonwoven fabric laminate described above.

The article may also be a diaper, an absorbent article, a toilet article, a support layer, a back sheet, a waistband or a top sheet.
When the article is a diaper, the nonwoven fabric laminate has a hydrophilic agent pick-up (OPU) of 0.7% or less, and when applied to the top sheet layer of the diaper, has a durable water absorption rate of 10 seconds or less.

The hydrophilic agent impregnation amount (OPU) can also be calculated by the following Equation 1.
[Formula 1]
OPU (%) = (W1-W0)/W0X100
In Equation 1, W0 is the weight of the nonwoven fabric laminate without a hydrophilic agent, and W1 is the weight of the nonwoven fabric laminate with a hydrophilic agent. Also, in Equation 1, W1 is the sum of the weight of the nonwoven fabric laminate without a hydrophilic agent and the weight of only the solid component of the hydrophilic agent.

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

Examples 1-9 and Comparative Examples 1 and 2: Production of Nonwoven Fabrics First, the polymer for forming Side A and the polymer for forming Side B were melted in separate extruders at temperatures between 180°C and 250°C to form melts for forming Side A and Side B, respectively. The melts were then extruded through a spinneret with a multi-spinning nozzle. The extruded melts were then divided into upper and lower regions, and passed through a stretching zone where the volume of the upper region was 90% of the volume of the lower region, where they were stretched. The extruded melts were then discharged through a diffuser with a trapezoidal cross section. Mechanical properties were imparted to the formed nonwoven fabrics by embossing using a heated embossing roll. Subsequently, as an optional post-processing step, the formed nonwoven fabrics were fed to a post-processing facility, where a deep embossing roll was used to impart a three-dimensional shape to the surface of the nonwoven fabric. The processing roll of the post-processing equipment was configured to perform deep embossing processing through perforations of 30 holes/inch, and to impart a three-dimensional shape to the surface of the nonwoven fabric.

The types, properties, and content ratios of the polymers for forming Side A and Side B are shown in Table 1 below. In Table 1 below, MFR refers to the melt index measured at a temperature of 230°C and a load of 2.16 kg according to ASTM D1238.

(1) PA1: Propylene homopolymer (H7700 (manufactured by LG Chemical))
(2) PB1: Propylene homopolymer (HP562T (manufactured by PMC))
(3) PB2: Propylene homopolymer (HP552R (manufactured by PMC))

The types, content ratios, physical properties, diffuser dimensions (top width: middle width: bottom width), and perforation levels of the polymers used in Examples 1 to 9 and Comparative Examples 1 and 2 are shown in Table 2 below. In Table 2 below, the physical properties of Side A refer to the physical properties of polymer (PA1), and the physical properties of Side B refer to the physical properties of the blend of polymer (PB1) and polymer (PB2).

Evaluation Example: Evaluation of Physical Properties of Nonwoven Fabrics The physical properties of the nonwoven fabrics produced in Examples 1 to 9 and Comparative Examples 1 and 2 were evaluated by the following methods, and the results are shown in Table 3 below.

(1) Weight per unit area (weight: g/m ² ): Measured according to ASTM D3776-1985.

(2) Tensile strength: Using an Instron tensile strength and elongation tester, a tensile test was conducted according to the KSK 0520 method, with test pieces 5 cm wide, spaced 10 cm apart, and at a tensile speed of 500 mm/min, to determine the maximum tensile load.

(3) Tensile elongation: The elongation at maximum elongation measured using the method in (2) above was determined.

(4) Coefficient of friction (C.O.F.): When a force is applied to a stationary object, the frictional force is proportional to the component of force perpendicular to the object. The proportionality constant is called the coefficient of static friction, and this coefficient of static friction is determined by the state of the contacting object and the state of the contact surface. The coefficient of static friction was measured using a KSM 3009.

(5) Thickness (mm): Measured using the block-cage thickness measurement method, which has a wide measurement area and allows for measurements with minimal load.

(6) Crimp count: The number of filament crimps within a 10 mm range was directly measured using a microscope.

(7) Spinnability: During melt spinning, filament sway was observed with the naked eye, and polymer drips were detected using a defect detector.

Referring to Table 3, it can be seen that the nonwoven fabrics produced in Examples 1 to 9 were thicker, had a lower coefficient of friction (COF), and had a higher number of crimps than the nonwoven fabrics produced in Comparative Examples 1 and 2.

Although the present invention has been described with reference to the drawings and embodiments, they are merely illustrative, and those skilled in the art will understand that various modifications and equivalent embodiments are possible therefrom. Therefore, the true technical scope of protection of the present invention is defined by the technical spirit of the claims.

Claims (11)

A nonwoven fabric containing crimped composite fibers,
The crimped composite fiber has a thickness direction cross section including a side A and a side B,
The ratio (Side B/Side A) of the melt flow rate (MFR) of Side A to Side B measured by ASTM D1238 (measurement temperature: 230°C, load: 2.16 kg) is 1.21 to 1.51,
The component ratio represented by the side A/the side B (weight ratio) is 50/50 to 70/30,
the ratio of the molecular weight distribution of the side A to the molecular weight distribution of the side B (the side B/the side A) is 1.32 to 1.5;
the side A includes a first propylene-based polymer, and the side B includes a second propylene-based polymer, the first propylene-based polymer and the second propylene-based polymer having different melt indexes and molecular weight distributions, respectively;
the melting point of the first propylene polymer and the melting point of the second propylene polymer are each independently in the range of 120 to 175°C;
the first propylene polymer has a molecular weight distribution of 2.0 to 3.0, and the second propylene polymer has a molecular weight distribution of 2.5 to 3.5;
Side B further comprises a third propylene polymer, the second propylene polymer and the third propylene polymer having different melting points and molecular weight distributions, and a component ratio (weight ratio) of the third propylene polymer to the second propylene polymer is 20/80 to 50/50;
The third propylene polymer has a melting point in the range of 120 to 175°C and a molecular weight distribution of 4.0 to 5.0 . The nonwoven fabric according to claim 1, having a thickness of 0.25 mm or more and a crimp count of 20 or more per 10 mm. The nonwoven fabric according to claim 1, having a coefficient of friction (COF) of 0.60 or less. The nonwoven fabric according to claim 1, wherein the crimped composite fiber is a side-by-side or sandwich composite fiber. The nonwoven fabric according to claim 1, wherein the nonwoven fabric is a spunbond nonwoven fabric. A nonwoven fabric laminate having a layer structure of at least two layers, at least one of which is the nonwoven fabric according to any one of claims 1 to 5 . The nonwoven fabric laminate according to claim 6 , wherein the nonwoven fabric is a spunbonded nonwoven fabric, and the nonwoven fabric laminate is configured such that the spunbonded nonwoven fabric is exposed on only one of the two surface layers. An article comprising the nonwoven laminate of claim 7 . 9. The article of claim 8 , wherein the article is a diaper, an absorbent article, a toileting product, a support layer, a backsheet, a waistband, or a topsheet. Step (S10) of melting the polymer for forming Side A and the polymer for forming Side B in separate extruders at a temperature of 180°C to 250°C in separate sections to form a melt of the polymer for forming Side A and a melt of the polymer for forming Side B;
(S20) discharging each of the melts through a spinneret having a composite spinning nozzle;
A step (S30) of dividing each of the discharged melts into an upper region and a lower region, and passing the melts through a stretching region in which the volume of the upper region is 90% or more of the volume of the lower region, and stretching the melts;
and discharging each of the drawn melts through a diffuser (S40),
the diffuser has a trapezoidal cross section, and the ratio of top width: middle width: bottom width is 1:1.5 or more:2.0 or more;
the ratio (Side B/Side A) of the melt flow rate (MFR) of the polymer for forming Side A to the polymer for forming Side B, as measured in accordance with ASTM D1238 (measurement temperature: 230°C, load: 2.16 kg), is 1.21 to 1.51;
the component ratio represented by the polymer for forming the side A/the polymer for forming the side B (weight ratio) is 50/50 to 70/30,
the ratio of the molecular weight distribution of the polymer for forming side A to the molecular weight distribution of the polymer for forming side B (polymer for forming side B/polymer for forming side A) is 1.32 to 1.5;
the polymer for forming side A includes a first propylene-based polymer, and the polymer for forming side B includes a second propylene-based polymer, and the first propylene-based polymer and the second propylene-based polymer have different melt indexes and molecular weight distributions, respectively;
the melting point of the first propylene polymer and the melting point of the second propylene polymer are each independently in the range of 120 to 175°C;
the first propylene polymer has a molecular weight distribution of 2.0 to 3.0, and the second propylene polymer has a molecular weight distribution of 2.5 to 3.5;
the polymer for forming Side B further includes a third propylene-based polymer, the second propylene-based polymer and the third propylene-based polymer having different melting indices and molecular weight distributions, and a component ratio (weight ratio) of the third propylene-based polymer to the second propylene-based polymer is 20/80 to 50/50;
the third propylene polymer has a melting point in the range of 120 to 175°C and a molecular weight distribution of 4.0 to 5.0 . 11. The method of claim 10 , further comprising the step of (S50) imparting mechanical properties to the nonwoven fabric formed in the step (S40) by embossing using a heated embossing roll or by heat sealing by high-temperature airflow.