JP2020165011A - Nonwoven fabric and absorbent article using the same - Google Patents

Abstract

To provide a nonwoven fabric capable of maintaining its form under high load while suppressing a basis weight of the nonwoven fabric, and thereby suppressing liquid return.SOLUTION: There is provided a through-air nonwoven fabric in which a ratio of a thickness under a load of 50 gf/cm2 to a thickness under a load of 3.5 gf/cm2 is 0.5-0.8, and a fiber surface area per volume under the load of 50 gf/cm2 is 70-120 cm2/cm3.SELECTED DRAWING: None

Description

The present invention relates to a non-woven fabric used as a member of an absorbent article and an absorbent article using the same.

Conventionally, absorbent articles such as disposable diapers have a top sheet that is in direct contact with the skin and allows excrement fluid such as urine to permeate, an absorber that holds the excretory fluid on the back side, and an excretory fluid that is between them. A second sheet that diffuses urine throughout the absorber is widely used. In an absorbent article, the excrement is held by the absorber, but when a load is applied, the excrement may flow back to the skin side. The phenomenon in which the excrement fluid flows back from the absorber to the skin side in this way is called liquid return, and the liquid return causes damp discomfort and skin irritation due to water. Therefore, the absorbent article is required not to return the excrement liquid held by the absorber to the skin side, and the configuration of the second sheet corresponding to this demand has been studied.

The second sheet of the absorbent article is mainly composed of a through-air non-woven fabric. The through-air non-woven fabric is a non-woven fabric that is classified as a thermal bonded non-woven fabric and is sometimes called an air-through non-woven fabric. For example, by heat-treating a web of composite fibers composed of at least two types of thermoplastic resins having different melting points. can get. As a method of heat-treating the web, for example, a method of heat-bonding the fibers to each other by a heat treatment apparatus (for example, a hot air penetration type heat treatment machine, a hot air blowing type heat treatment machine) provided with a transport support for supporting and transporting the web to form a non-woven fabric. It has been known.

Regarding the second sheet, for example, Patent Document 1 has an effect of increasing the absorption rate on the surface of the diaper, preventing the reversion of body fluids, preventing the surface of the diaper from getting wet and fogging, and the surface of the diaper is highly flexible. It is an object to provide, and an absorbent article having a second sheet having a defined compressive hardness has been proposed. It is disclosed that the second sheet of Patent Document 1 is obtained by heat-bonding heat-adhesive composite fibers having a specific range of fineness with an air-through type heat treatment machine and then consolidating them. Further, it is disclosed that the thickness of the second sheet under a load of 0.5 gf / cm ² is 0.7 to 0.9 mm. The second sheet of Patent Document 1 is characterized by having a high density and abundant flexibility.

In addition, a non-woven fabric that suppresses liquid return by ensuring the thickness when a load is applied has been proposed. For example, Patent Document 2 discloses an air-through or air-laid nonwoven fabric having a basis weight of 30 g / m ² or more and a thickness of 0.35 mm to 1 mm under a load of 50 gf / cm ² as a second sheet. An object of the invention of Patent Document 2 is to provide a disposable diaper that does not easily return to liquid even when a large amount of urine is absorbed, and to this problem, a load applied by the weight of the wearer while wearing the diaper. It is considered that an excellent liquid return reducing effect can be achieved by maintaining the required thickness even under a high load (50 gf / cm ² ) assuming the above.

Further, for example, Patent Document 3 describes a spunlace non-woven fabric having a basis weight of 40 to 60 g / m ^{2 and made} of a polyester fiber having a single fiber fineness of 2 to 8 dtex and having a fiber surface hydrolyzed. A second sheet has been proposed, which is characterized by being formed of a binder.

Japanese Unexamined Patent Publication No. 2005-52186 Japanese Unexamined Patent Publication No. 2007-159943 JP-A-2017-148284

The second sheet of Patent Document 1 constitutes a sheet having a high density and a softness in order to obtain effects such as a highly flexible surface portion of the diaper in addition to preventing liquid return. However, due to this softness, the thickness under load becomes small, and the liquid return prevention property may not be sufficiently exhibited. Further, it is described that the thickness of the second sheet of Patent Document 2 is about 1.4 to 1.9 mm under a low load (49 Pa = 0.5 gf / cm ² ) in order to secure the thickness under a load. It was a non-woven fabric with a large thickness under a low load. Further, since the non-woven fabric of Patent Document 3 is a spunlace non-woven fabric, it has excellent flexibility but weak compression resistance, and it is necessary to increase the basis weight in order to secure the liquid return prevention property. It is disclosed that the basis weight is preferably 40 to 60 g / m ² .

In view of such a situation, the present invention provides a non-woven fabric that keeps the basis weight of the non-woven fabric low and maintains a constant thickness even under a high load, thereby suppressing liquid return.

The inventors have made repeated studies to solve the above-mentioned problems, and as a result, have come up with the idea of producing a non-woven fabric that is relatively thin under a low load and can maintain a constant thickness even under a high load. Then, in grasping the fragility of the non-woven fabric, pay attention to the thickness at low load (3.5 gf / cm ² load) and the thickness at high load (50 gf / cm ² load), and consider the thickness. The present invention was completed with the finding that by controlling the ratio and the surface area of the fiber per volume under a load of 50 gf / cm ² , liquid return can be reduced, and a non-woven fabric having low graininess and liquid return property can be obtained. did.

The present invention has the following configurations.
[1] for 3.5 gf / cm ² Thickness under load, the ratio of the thickness of the under 50 gf / cm ² load is 0.5 to 0.8, and, 50 gf / cm ² per volume under load Through-air non-woven fabric having a fiber surface area of 70 to 120 cm ² / cm ³ .
[2] The through-air non-woven fabric according to [1], which has a basis weight of 20 to 35 g / m ² .
[3] It is composed of polyethylene terephthalate and polyethylene, and is composed of a composite fiber which is one selected from the group consisting of a parallel type composite fiber, an eccentric sheath core type composite fiber and a concentric sheath core type composite fiber, [1] or The through-air non-woven fabric according to [2].
[4] A step of producing a web of a composite fiber which is composed of polyethylene terephthalate and polyethylene and is selected from the group consisting of a parallel type composite fiber, an eccentric sheath core type composite fiber and a concentric sheath core type composite fiber. The production of the through-air nonwoven fabric according to any one of [1] to [3], which comprises a step of heat-treating the web obtained in 1) by a through-air method and a step of compacting the web immediately after the heat treatment step. Method.
[5] An absorbent article comprising the through-air nonwoven fabric according to any one of [1] to [3].

The ratio of the thickness of the thickness and 50 gf / cm under a ² weight under 3.5 gf / cm ² load to maintain the shape of the nonwoven fabric by a 0.5 to 0.8, it is once absorbed into the absorbent body excretion The return of the liquid to the skin side can be suppressed. Further, by setting the fiber surface area per volume to 70 to 120 cm ² / cm ³ , it is possible to suppress the liquid diffusion due to the capillary phenomenon, and thereby the liquid return can be reduced. As described above, according to the present invention having the above-mentioned configuration, it has sufficient absorbency to the excreted liquid and the liquid return is suppressed even under a load.

Non-woven fabric of the present invention, to the thickness of the under 3.5 gf / cm ² load, a ratio of the thickness of the under 50 gf / cm ² load is 0.5 to 0.8, and, 50 gf / cm under ² Load at It is a through-air non-woven fabric having a fiber surface area of 70 to 120 cm ² / cm ³ per volume, and is suitably used as a second sheet of an absorbent article.

The non-woven fabric of the present invention is a through-air non-woven fabric, and as a raw material thereof, a non-woven fabric containing heat-adhesive fibers capable of adhering fibers to each other by heat can be used. For example, it may be a single type or a plurality of types of heat-adhesive composite fibers, or a plurality of types of heat-adhesive fibers may be mixed (mixed) and used. Preferably, a composite fiber having heat adhesiveness, in which a plurality of resins having different melting points are composited, can be mentioned. The heat-adhesive component of the composite fiber may be a thermoplastic resin component that heat-melts by passing hot air through the web made of the fiber to form an adhesive point. The thermal adhesion points between the fibers are formed by melting the thermoplastic resin component having a low melting point by hot air treatment. The resin component constituting the heat-adhesive fiber is a polyolefin-based (for example, polypropylene, propylene copolymer [a copolymer containing propylene as a main component and another α-olefin; for example, ethylene-propylene binary; Copolymer, propylene-butene-1 binary copolymer, propylene-hexene-1 binary copolymer, etc.], polyethylene, etc.), polyester-based (for example, polyethylene terephthalate), polyamide-based (for example, nylon 6, etc.) Can be exemplified. Specific combinations of the low melting point component and the high melting point component in the composite fiber include polyethylene (low melting point component) and polypropylene (high melting point component), polyethylene (low melting point component) and polyethylene terephthalate (high melting point component), and the like. Particularly, a composite fiber composed of polyethylene (low melting point component) and polyethylene terephthalate (high melting point component) is preferable in terms of bulkiness and strength of the non-woven fabric.

In addition to the above-mentioned heat-adhesive composite fibers, natural fibers (wooden fibers, etc.), recycled fibers (rayons, etc.), semi-synthetic fibers (acetates, etc.) and chemical fibers are used on the web for producing through-air non-woven fabrics. Fibers that are not so-called heat-adhesive fibers such as fibers and synthetic fibers (polyester, acrylic, nylon, vinyl chloride, etc.) (hereinafter referred to as "non-heat-adhesive fibers") may be included. The "non-thermally adhesive fiber" refers to a fiber that does not undergo a thermal change (melting or softening) that is involved in thermal bonding in the thermal bonding performed when manufacturing a non-woven fabric. When non-heat-adhesive fibers are included, the proportion of non-heat-adhesive fibers to the total weight of the web is not limited as long as it does not interfere with the effects of the invention, but can be, for example, 1-30% by weight, preferably 1-30% by weight. It is 3 to 15% by weight.

The shape of the composite fiber can be exemplified by a concentric sheath core type, an eccentric sheath core type, and a parallel type in a cross section perpendicular to the longitudinal direction thereof. In the case of concentric sheath-core type composite fibers and eccentric sheath-core type composite fibers, it is preferable that the low melting point component constitutes the sheath component and the high melting point component constitutes the core component.

When the web is produced by a card machine using the composite fiber as a raw material, the composite fiber needs to have crimping. In the case of concentric sheath-core type composite fibers, a crimper can be used to impart a zigzag-shaped mechanical crimp. Further, in the case of the eccentric sheath core type composite fiber, a zigzag-shaped mechanical crimp can be imparted by a crimper, and a three-dimensional crimp can be imparted by a stretching or drying step. If the number of crimps is 7.0 to 20.0 ridges / 2.54 cm, the passability of the card machine is good, and if it is 11.0-16.0 ridges / 2.54 cm, the obtained web The condition of is good.

Through-air nonwoven fabric of the present invention, the ratio of the thickness of the under 50 gf / cm ² load to the thickness under 3.5 gf / cm ² load has a characteristic of being 0.5 to 0.8. It is considered that the non-woven fabric that does not change significantly in thickness under low load and high load and is "hard to crush" can sufficiently separate the absorber from the top sheet and has excellent liquid return prevention properties. Has been done. A conventional second sheet that is relatively thick under a low load (for example, 1 mm or more) and that can maintain a constant thickness even if most of the thickness of the low load is crushed under a high load has been studied. I came. However, in the present invention, by using a non-woven fabric that is relatively thin from a low load and is not easily crushed even under a high load, the thickness of the water-absorbent article itself can be reduced when mounted on the absorbent article, and the absorbency is also reduced. It is possible to suppress the stiffness of the surface portion of the article. It is important that the thickness ratio is 0.5 to 0.8, preferably 0.6 to 0.7.

Further, the through-air nonwoven fabric of the present invention is characterized in that the fiber surface area per volume under a load of 50 gf / cm ² is 70 to 120 cm ² / cm ³ . Here, the fiber surface area per volume is the total surface area of the fibers contained in 1 cm ³ (1 cc) of the non-woven fabric, and is a value calculated from the surface area of the constituent fibers and the fiber density of the non-woven fabric. The fiber surface area and the fiber surface area per volume are calculated by the following equations (1) and (2).

(1) Fiber surface area (cm ² / g) = fiber diameter (μm) ÷ 10000 (μm / cm) × π × 10000 (m) × 100 (cm / m) ÷ fiber 10000 m weight (g)

(2) Fiber surface area per volume (cm ² / cm ³ ) = Fiber surface area (cm ² / g) x Fiber density of non-woven fabric (g / cm ³ )

Although not particularly bound by theory, in the present invention, the fiber surface area per volume of the nonwoven fabric under load is considered to be related to the capillary phenomenon occurring in the nonwoven fabric, and under a load of 50 gf / cm ² . In the range where the fiber surface area per volume is 70 to 120 cm ² / cm ³ , excellent permeability of excrement liquid such as urine to the absorber can be obtained, and liquid return can be suppressed. The through-air non-woven fabric of the present invention has excellent liquid permeability and excellent liquid return, particularly when the above-mentioned "difficulty of crushing" is within a certain range and the fiber surface area per volume of the non-woven fabric is within a certain range. It is believed that preventive properties can be obtained.

The basis weight of the through-air nonwoven fabric of the present invention is not limited as long as it satisfies the above constitution and the effect of the present invention can be obtained, but it can be, for example, 20 to 35 g / m ² and 25 to 33 g / m ^2. Is more preferable. The through-air non-woven fabric of the present invention has a relatively low basis weight as a second sheet, but has excellent liquid return prevention properties, so that the weight and compactness of the entire absorbent article can be reduced.

The fineness of the fibers constituting the through-air nonwoven fabric of the present invention is not limited as long as it satisfies the above constitution and the effect of the present invention can be obtained, but can be, for example, 2.0 to 20 dtex, preferably 3 to 15 dtex. , More preferably in the range of 5-10 dtex. If a fiber having a fineness of 20 dtex or more is used, it becomes a non-woven fabric having a hard tactile sensation, which adversely affects the tactile sensation of the surface when mounted on an absorbent article, and is high by using a fiber having a fineness of 2.0 dtex or less. It is thought that the thickness cannot be maintained under load and the liquid return is promoted.

To the non-woven fabric of the present invention, a deodorant component, an anti-allergen component, an antibacterial component, a wetting component, a moisturizing component and the like can be added as long as the effects of the present invention are not impaired. These components are added by a method of adhering to the non-woven fabric by spraying or the like, a method of kneading into at least one of the thermoplastic composite fibers of the non-woven fabric, or a method of adhering to the fiber surface. Can be done.

The absorbent article using the non-woven fabric of the present invention as a second sheet is used, for example, as a diaper such as a disposable diaper, a urine pad, a menstrual blood absorbing pad, and the like. The absorbent article using the nonwoven fabric of the present invention as a second sheet may have a conventionally known configuration other than using the above-mentioned through-air nonwoven fabric as the second sheet. Specifically, for example, the following configuration is used. can do.

Absorbent articles include a top sheet, a second sheet, an absorber, and a waterproof back sheet. As the top sheet, for example, a through-air non-woven fabric single layer or laminated can be used. The absorber is typically composed of an absorbent material. As the absorbent material, a known absorbent material that can be used for an absorbent article such as a disposable diaper can be used. Specific examples thereof include fluff pulp, super absorbent polymer (SAP), hydrophilic sheet and the like, and one or more of these can be used.

As the fluff pulp, wood pulp or non-wood pulp defibrated into cotton is preferable. As the SAP, sodium polyacrylate is preferable. As the hydrophilic sheet, non-woven fabric can be used in addition to tissue paper and absorbent paper. When a non-woven fabric is used, it is preferably hydrophilized. Further, as a measure against shape loss, synthetic fibers such as heat-sealed fibers may be included. These materials may be used alone or in combination. For example, as a preferable absorbent material, a material in which about 10 to 500 parts by mass of SAP is used in combination with 100 parts by mass of fluff pulp can be mentioned. Be done.

The absorber is usually used in the form of a single-layer or multi-layer mat. When the fluff pulp and the SAP are used together, the SAP may be uniformly mixed in the mat of the fluff pulp, or may be arranged in layers between the layers of the multi-layered fluff pulp. Further, when SAP is used as the absorber in this way, the entire absorber layer is made hydrophilic in order to prevent leakage of SAP from the absorber layer and to impart shape stability to the absorber layer. It is preferable to cover with a sheet.

A waterproof back sheet is provided on the lower surface side of the absorber in order to prevent the object to be absorbed from leaking to the outside of the absorbent article. The back sheet forms the outermost layer of the absorbent article, and is a layer located on the clothing side of the wearer when the absorbent article is worn by the wearer. Examples of the material constituting the back sheet include a liquid-impermeable film made of a resin such as polyethylene, and among them, a microporous polyethylene film is preferably used. The microporous polyethylene film has a large number of fine pores of 0.1 to several μm formed, and is impermeable to liquid but has moisture permeability. Therefore, by using this, an absorbent article can be obtained. Can prevent internal stuffiness.

A cover made of paper cloth, woven fabric, spunlace non-woven fabric, spunbond non-woven fabric, etc. is provided on the outermost surface of the back sheet to further reinforce it and improve the feel during use. A sheet may be provided. Among them, spunbonded non-woven fabric is preferably used in terms of strength and cost.

Further, the absorbent article may have a fixing means for preventing the absorbent article from being displaced. Examples of the fixing means include an adhesive tape and the like, which are provided at one or more places on the outermost surface of the absorbent article. In addition, for example, an elastic band, an elastic tape, gathers for forming a three-dimensional shape, and the like can have any various configurations depending on the purpose.

(Production method)
The non-woven fabric of the present invention is a through-air non-woven fabric, and a method for producing a web can be obtained by appropriately selecting known methods and conditions. As described above, it is preferable to prepare a web using a composite fiber having heat adhesiveness in which a plurality of resins having different melting points are composited. The obtained web is placed on a transport support (belt conveyor) and fed into the heat treatment apparatus. In the heat treatment device, heating is performed to a temperature at which only the low melting point resin of the composite fiber melts, and the melted low melting point resins adhere to each other (heat adhesion), so that the intersections of the fibers are fused and then cooled. As a result, a through-air non-woven fabric having a three-dimensional structure is manufactured. Further, in the present invention, it is preferable that the web is compacted by, for example, a roll or a plate in a state where the low melting point resin of the fiber is melted by a heat treatment machine, and the fibers are forcibly brought into contact with each other to be thermally bonded. Consolidation may be performed after the heat treatment, but is preferably performed immediately after the heat treatment following the heat treatment. By this step, the adhesive points in the non-woven fabric are increased, and a non-woven fabric that is not easily crushed under a high load can be obtained.

Hereinafter, the present invention will be described in more detail by way of examples, but the following examples are for purposes of illustration only. The scope of the present invention is not limited to this embodiment.

The measurement method and definition of the physical property values used in the examples and comparative examples are shown below.

<Metsuke of non-woven fabric>
A non-woven fabric was cut into a square of 10 cm × 10 cm, the weight of the non-woven fabric was measured, converted per unit area, and rounded off to the first decimal place.

<Thickness of non-woven fabric>
Cut out the non-woven fabric into a square of 10 cm x 10 cm, and compress the non-woven fabric with a 2 cm ² pressure plate using "Handy-Compressor KES-G5" (trade name) manufactured by Katou Tech, and 3.5 gf / cm ² , 50 gf /. The thickness at each cm ² was measured.

<Thickness ratio of non-woven fabric>
For 3.5 gf / cm ² load at a thickness, a ratio of the thickness at 50 gf / cm ² load, represented by the following formula.
Thickness ratio = 50 gf / cm Thickness under ² loads ÷ 3.5 gf / cm Thickness under ² loads

<Fiber surface area per volume of non-woven fabric under 50 gf / cm ² load>
The fiber surface area was calculated from the fiber diameter of the composite fiber constituting the non-woven fabric. For the fiber diameter, a magnified photograph of the surface of the non-woven fabric was taken using a scanning electron microscope (SEM), the diameters of 20 fibers were measured, and the arithmetic mean value was used. The fiber surface area and the fiber surface area per volume were calculated by the following equations (1) and (2).
(1) Fiber surface area (cm ² / g) = fiber diameter (μm) ÷ 10000 (μm / cm) × π × 10000 (m) × 100 (cm / m) ÷ fiber 10000 m weight (g)
(2) Fiber surface area per volume (cm ² / cm ³ ) = Fiber surface area (cm ² / g) x Fiber density of non-woven fabric (g / cm ³ )
By multiplying the nonwoven density under 50 gf / cm ² load to fiber surface area was calculated fiber surface area per nonwoven volume under 50 gf / cm ² load ^(cm 2 / cm ^3).

<Liquid return test>
It was evaluated by a method according to EDANA-ERT 151.1-96. The absorbent paper used was Kim Towel (trade name) manufactured by Crecia Co., Ltd. cut into approximately 90 mm x 90 mm (adjusted to 5.00 to 5.05 g), and 15 ml of physiological saline was permeable. Absorbed. The amount of liquid return was determined according to the following criteria. It was judged that the smaller the amount of liquid returned, the better the non-woven fabric.
◯: less than 2.0 g Δ: 2.0 g or more, less than 3.0 g ×: 3.0 g or more

[Example 1]
A non-woven fabric having a basis weight of 31 g / m ² was produced, which consisted of a sheath-core type composite fiber having a fineness of 5.6 dtex, a sheath component of polyethylene, and a core component of polyethylene terephthalate. First, the composite fiber was made into a web by a carding method. A hot air circulation type suction band dryer at 138 ° C. was used to pass hot air through the obtained web to bond the interfiber confounding points constituting the web, and immediately after that, the web was compressed using a metal roller. It was produced by forcibly promoting thermal adhesion between fibers.
The nonwoven fabric fiber surface area per volume during nonwoven thickness ratio = 0.69,50gf / cm ² load is 95cm ² / cm ^3, liquid return was obtained good results with 1.6 g.

[Examples 2 to 3]
The non-woven fabric shown in Table 1 was prepared in the same manner as in Example 1 using the concentric sheath core type heat-adhesive composite fibers shown in Table 1. Table 1 shows the results of evaluation in the same manner as in Example 1. As the raw material fiber, a sheath-core type composite fiber having a sheath component of polyethylene and a core component of polyethylene terephthalate having 9.0 dtex in Example 2 and 20 dtex in Example 3 was used as a raw material for the non-woven fabric.
In all cases, liquid return was suppressed and good results were obtained.

[Comparative Example 1]
A non-woven fabric having a basis weight of 30 g / m ² was produced, which consisted of a sheath-core type composite fiber having a fineness of 5.6 dtex, a sheath component of polyethylene, and a core component of polyethylene terephthalate. First, the composite fiber was made into a web by a carding method. The interfiber entanglement points constituting the web were adhered by passing hot air through the obtained web using a hot air circulation type suction band dryer at 138 ° C. Then, the non-woven fabric was produced without compressing the web using a metal roller. The nonwoven fabric fiber surface area per volume during nonwoven thickness ratio 0.12,50gf / cm ² load was 555cm ² / cm ^3, liquid return was obtained 2.6g and poor outcome.

[Comparative Examples 2-3]
The non-woven fabric shown in Table 1 was prepared in the same manner as in Comparative Example 1 using the concentric sheath core type heat-adhesive composite fibers shown in Table 1. Table 1 shows the results of evaluation in the same manner as in Comparative Example 1. As the raw material fiber, a sheath-core type composite fiber having a sheath component of polyethylene and a core component of polyethylene terephthalate having 5.6 dtex in Comparative Example 2 and 9.0 dtex in Comparative Example 3 was used as a raw material for the non-woven fabric. In each case, the liquid return could not be suppressed and poor results were obtained.

Example 1 and Comparative Example 1 and Example 2 and Comparative Example 3 are examples in which the fibers constituting the non-woven fabric are the same, and only the presence or absence of consolidation treatment after the production of the through-air non-woven fabric is different. As shown in Table 1, Example 1 and Comparative Example 1, respectively Comparative Example 3 and Example 2, the thickness of the under 3.5 gf / cm ² load is almost the same, 50 gf / cm under ² Load at It can be seen that the non-woven fabrics of Examples 1 and 2 are not easily crushed even under a load, and the fiber surface area per volume is maintained within a certain range even under a load. As shown in Table 1, by controlling the non-woven fabric thickness ratio of the through-air non-woven fabric and the fiber surface area per volume under a load of 50 gf / cm ² within a specified range, liquid return could be significantly suppressed.

The through-air non-woven fabric of the present invention can be used as a second sheet mounted on diapers such as disposable diapers, urine pads, menstrual blood absorption pads and the like.

Claims (5)

For 3.5 gf / cm ² Thickness under load, the ratio of the thickness of the under 50 gf / cm ² load is 0.5 to 0.8, and fiber surface area per volume under 50 gf / cm ² load A through-air non-woven fabric having a surface area of 70 to 120 cm ² / cm ³ . The through-air nonwoven fabric according to claim 1, which has a basis weight of 20 to 35 g / m ² . The first or second claim, wherein the polyethylene terephthalate and polyethylene are composed of a composite fiber which is one of the group consisting of a parallel type composite fiber, an eccentric sheath core type composite fiber and a concentric sheath core type composite fiber. Through-air non-woven fabric. A step of producing a web of composite fibers, which is composed of polyethylene terephthalate and polyethylene and is selected from the group consisting of parallel type composite fibers, eccentric sheath core type composite fibers and concentric sheath core type composite fibers.
A step of heat-treating the web obtained in the above step by the through-air method, and
A step of compacting the web immediately after the heat treatment step is included.
The method for producing a through-air nonwoven fabric according to any one of claims 1 to 3. An absorbent article comprising the through-air nonwoven fabric according to any one of claims 1-3.