JP2024007880A - Nonwoven fabric for absorbent article and nonwoven fabric manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric for absorbent article that can suppress delamination and is excellent in liquid permeability and liquid repellency.

SOLUTION: A nonwoven fabric for absorbent article 16 has a first fiber layer 26 and a second fiber layer 28 in order in a thickness direction T. The first fiber layer 26 has a first surface 22 and is formed of thermally fusible fibers. The second fiber layer 28 includes water-absorbing fibers and thermally fusible fibers. A portion of the thermally fusible fibers of the first fiber layer 26 enters into the second fiber layer 28 and fuses with a portion of the thermally fusible fibers of the second fiber layer 28. The water-absorbing fibers of the second fiber layer 28 are not exposed to the first surface 22.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a nonwoven fabric for absorbent articles and a method for manufacturing the nonwoven fabric.

As a nonwoven fabric for absorbent articles, for example, Patent Document 1 discloses that a cotton web and a synthetic short fiber web containing heat-adhesive short fibers are laminated, and the constituent fibers of the cotton web are laminated together, and the cotton and synthetic short fiber web are laminated. It is a composite nonwoven fabric in which the constituent fibers of the synthetic short fiber web and the constituent fibers of the synthetic short fiber web are three-dimensionally intertwined and integrated, and the intersection points of the fibers are thermally bonded by the fusion of the thermal adhesive component. A composite nonwoven fabric is disclosed.

Moreover, Patent Document 2 includes a first fiber layer and a second fiber layer located on one main surface of the first fiber layer, the first fiber layer includes a first core-sheath type composite fiber, and a second fiber layer includes a first fiber layer and a second fiber layer located on one main surface of the first fiber layer. The fiber layer includes a second core-sheath type composite fiber and a cellulose fiber, the fineness of the first core-sheath type composite fiber is smaller than the fineness of the second core-sheath type composite fiber, and the fineness of the first core-sheath type composite fiber is smaller than the fineness of the first core-sheath type composite fiber. is 1.0 to 2.8 dtex, the fineness of the second core-sheath composite fiber is 1.7 to 5.6 dtex, the fineness of the cellulose fiber is 1.2 to 6.0 dtex, and the second fiber A nonwoven fabric for an absorbent article is disclosed, the layer comprising cellulosic fibers in a proportion of 5% to 40% by weight, based on the total weight of the second fibrous layer.

Japanese Patent Application Publication No. 11-229256 JP2020-171688A

In the nonwoven fabric of Patent Document 1, by applying high-pressure fluid treatment to the laminated webs, the constituent fibers of the cotton web, the constituent fibers of the cotton and synthetic short fiber web, and the constituent fibers of the synthetic short fiber web are three-dimensionally bonded to each other. are intertwined and integrated. The nonwoven fabric has a low bulk because the web receives a large force in the thickness direction from the high-pressure fluid. When a nonwoven fabric is used as a top sheet of an absorbent article, it has a low bulk, so it is difficult for liquid to pass through the fabric in the thickness direction, and the nonwoven fabric has poor liquid permeability.

Patent Document 2 states that it is preferable to join the first fiber layer and the second fiber layer by the air-through method (hot air penetration type heat treatment method) because it is easy to obtain a nonwoven fabric with good texture. There was a problem that since there were few contact points between the fibers of the first fiber layer and the second fiber layer, there were few places where the fibers could be fused together, and the first fiber layer and the second fiber layer were likely to separate. As the number of cellulose fibers included in the second fiber layer increases, the number of fused portions between the first fiber layer and the second fiber layer decreases, and therefore it becomes easier for separation between the first fiber layer and the second fiber layer.

An object of the present invention is to provide a nonwoven fabric for absorbent articles that can suppress delamination and has excellent liquid permeability, and a method for producing the nonwoven fabric for absorbent articles.

The present invention is a nonwoven fabric for an absorbent article comprising a first fiber layer and a second fiber layer in order in the thickness direction, wherein the first fiber layer has a first surface and is made of heat-fusible fibers. The second fiber layer includes water-absorbing fibers and heat-fusible fibers, and a portion of the heat-fusible fibers of the first fiber layer enters the second fiber layer to form the second fiber layer. The water-absorbing fibers of the second fiber layer are a nonwoven fabric that is fused to some of the heat-fusible fibers of the fiber layer and is not exposed to the first surface.

The present invention provides for a first fiber web made of heat-fusible fibers and a second fiber web containing water-absorbing fibers and heat-fusible fibers stacked in order in the thickness direction, on the side of the first fiber web. a first step of injecting gas from the fiber web, and melting the surfaces of the heat-fusible fibers of the first fiber web and the heat-fusible fibers of the second fiber, and fusing the heat-fusible fibers to each other. a second step of moving the heat-fusible fibers of the first fibrous web in a thickness direction that is larger than a movement amount of the heat-fusible fibers of the first fiber web in a width direction perpendicular to the machine direction. This is a method for producing a nonwoven fabric for absorbent articles, in which the gas is injected under certain conditions.

The nonwoven fabric for absorbent articles according to the present invention can suppress delamination and has excellent liquid permeability. The method for manufacturing a nonwoven fabric for absorbent articles according to the present invention can suppress delamination and produce a nonwoven fabric with excellent liquid permeability.

FIG. 1 is a diagram schematically showing an absorbent article according to an embodiment. 2 is an end view schematically showing a cross section taken along line II-II in FIG. 1. FIG. FIG. 3 is a partially enlarged sectional view of the top sheet. It is a schematic diagram showing the manufacturing process of the nonwoven fabric concerning this embodiment. FIG. 7 is a partially enlarged sectional view schematically showing a nonwoven fabric according to a modified example. 1 is a microscopic photograph of a cross section of a nonwoven fabric according to Example 1. 1 is a microscopic photograph of a cross section of a nonwoven fabric according to Comparative Example 1. 3 is a microscopic photograph of a cross section of a nonwoven fabric according to Comparative Example 2. 1 is a microscopic photograph of a cross section of a nonwoven fabric according to Reference Example 1.

Embodiments of the present invention relate to the following aspects.

[Aspect 1]
A nonwoven fabric for an absorbent article comprising a first fiber layer and a second fiber layer in order in the thickness direction,
The first fiber layer has a first surface and is made of heat-fusible fibers,
The second fiber layer includes water-absorbing fibers and heat-fusible fibers,
Some of the heat-fusible fibers of the first fiber layer enter the second fiber layer and are fused with some of the heat-fusible fibers of the second fiber layer, The water-absorbing fibers of the fibrous layer are not exposed on the first surface.
In the nonwoven fabric, some of the heat-fusible fibers of the first fiber layer and some of the heat-fusible fibers of the second fiber layer are fused together. That is, some of the heat-fusible fibers of the first fiber layer enter the second fiber layer, contact and fuse with some of the heat-fusible fibers included in the second fiber layer. Therefore, in the nonwoven fabric, since the first fiber layer and the second fiber layer are firmly joined, delamination between the first fiber layer and the second fiber layer can be suppressed.
The water-absorbing fibers of the second fiber layer are formed in the second fiber layer by some of the heat-fusible fibers of the first fiber layer and some of the heat-fusible fibers of the second fiber layer being fused to each other. Retained. The water-absorbing fibers of the second fiber layer are not exposed to the first surface, so they are difficult to fall off from the first surface. Therefore, in the nonwoven fabric, the fibers of the second fiber layer are prevented from coming off.

When the nonwoven fabric is used as a top sheet of an absorbent article and the first surface is the skin-facing surface, body fluids supplied to the skin-facing surface migrate from the skin-facing surface to the inside of the first fiber layer. Furthermore, when the second surface is the skin-facing surface, the body fluid supplied to the skin-facing surface migrates from the skin-facing surface into the inside of the second fiber layer. Since the nonwoven fabric includes a first fiber layer made of heat-fusible fibers and a second fiber layer containing water-absorbing fibers and heat-fusible fibers, it is bulky and has excellent liquid permeability.

As a result, the nonwoven fabric can suppress delamination between the first fiber layer and the second fiber layer, and has excellent liquid permeability.

[Aspect 2]
The nonwoven fabric according to aspect 1, wherein the first fiber layer has no recesses formed in the thickness direction on the first surface.
If a concave portion recessed in the thickness direction is formed on the first surface, the liquid permeability will decrease because the volume of this portion is low.
On the other hand, the nonwoven fabric of the present invention does not have a concave portion depressed in the thickness direction on the first surface, so body fluids are prevented from accumulating in a specific location. Therefore, the nonwoven fabric has excellent liquid permeability.

[Aspect 3]
The nonwoven fabric according to aspect 1 or 2, comprising a third fiber layer made of heat-fusible fibers on the opposite side of the second fiber layer to the first fiber layer.
In the nonwoven fabric, the surface of the third fiber layer disposed on the opposite side of the first fiber layer of the second fiber layer and the opposite side of the second fiber layer serves as the second surface. The second fiber layer is covered by the third fiber layer, and exposure of the water absorbent fibers from the second surface is suppressed. Therefore, in the nonwoven fabric, the water-absorbing fibers are prevented from coming off.

[Aspect 4]
A further part of the heat-fusible fibers of the first fiber layer that have entered the second fiber layer penetrate the second fiber layer, enter the third fiber layer, and form the third fiber layer. The nonwoven fabric according to aspect 3, wherein the nonwoven fabric is fused to some of the heat-fusible fibers of the layer.

In the nonwoven fabric, some of the heat-fusible fibers of the first fiber layer are further fused to some of the heat-fusible fibers of the third fiber layer. That is, some of the heat-fusible fibers in the first fiber layer have entered the second fiber layer, and further, some of them have penetrated the second fiber layer, entered the third fiber layer, and formed the third fiber. It is fused with some of the heat-fusible fibers of the layer. Therefore, since the nonwoven fabric is firmly bonded not only between the first fiber layer and the second fiber layer but also between the second fiber layer and the third fiber layer, delamination can be suppressed.
The water-absorbing fibers of the second fiber layer pass through some of the heat-fusible fibers of the first fiber layer and some of the heat-fusible fibers of the second fiber layer, which are fused to each other, and the second fiber layer. A further part of the heat-fusible fibers of the first fiber layer and a part of the heat-fusible fibers of the third fiber layer hold each other in the second fiber layer. Therefore, in the nonwoven fabric, the loss of fibers in the second fiber layer is further suppressed.

[Aspect 5]
Some of the heat-fusible fibers of the second fiber layer enter the third fiber layer, and a further part of the heat-fusible fibers of the first fiber layer and the heat-fusible fibers of the third fiber layer enter the third fiber layer. The nonwoven fabric according to aspect 4, which is fused to a part of the adhesive fibers.

Some of the heat-fusible fibers of the second fiber layer have entered the third fiber layer, and are fused with some of the heat-fusible fibers of the third fiber layer in the third fiber layer, Further, it is fused to a further portion of the heat-fusible fibers of the first fiber layer that have penetrated the second fiber layer and entered the third fiber layer. Therefore, in the nonwoven fabric, since the second fiber layer and the third fiber layer are more firmly joined, delamination can be further suppressed.
The water-absorbing fibers of the second fiber layer are a part of the heat-fusible fibers of the second fiber layer and a part of the heat-fusible fibers of the third fiber layer, which are fused to each other, and the second fiber layer is fused to each other. The fibers are held in the second fiber layer by a further part of the heat-fusible fibers of the first fiber layer and a part of the heat-fusible fibers of the second fiber layer that have penetrated through them. Therefore, in the nonwoven fabric, the loss of fibers in the second fiber layer is further suppressed.

[Aspect 6]
The nonwoven fabric according to any one of aspects 1 to 5, wherein the first surface of the first fiber layer is a skin-facing surface.
When a nonwoven fabric is used as the top sheet of an absorbent article and the first surface is the skin-facing surface, body fluids supplied to the skin-facing surface migrate from the skin-facing surface into the inside of the first fiber layer. Since the water-absorbing fibers are not exposed on the surface facing the skin, body fluids are less likely to remain on the surface facing the skin. The body fluid that has migrated into the first fiber layer further migrates in the thickness direction and reaches the interface between the first fiber layer and the second fiber layer. The body fluid smoothly transfers to the second fiber layer because some of the heat-fusible fibers of the first fiber layer have entered the second fiber layer. The body fluid transferred to the second fiber layer is absorbed by the water absorbent fibers included in the second fiber layer. When the nonwoven fabric is used as a top sheet of an absorbent article, body fluids absorbed by the water absorbent fibers are absorbed by the absorbent body placed on the non-skin side. In this way, the nonwoven fabric smoothly transfers body fluids supplied to the skin-facing surface from the first fiber layer to the second fiber layer, and absorbs them with the water-absorbing fibers of the second fiber layer, resulting in improved liquid repellency. Excellent.

[Aspect 7]
The nonwoven fabric according to aspect 6, wherein the second fiber layer has a uniform basis weight in a plane direction.
Since the basis weight of the second fiber layer is uniform in the surface direction, body fluids supplied to the skin-facing surface and transferred in the thickness direction are uniformly absorbed regardless of the position in the surface direction. Therefore, the nonwoven fabric can provide excellent liquid repellency regardless of its position in the surface direction.

[Aspect 8]
The nonwoven fabric according to aspect 6 or 7, wherein the second fiber layer contains the water-absorbing fibers in an amount of 40% by mass or more and 70% by mass or less.
Since the nonwoven fabric contains 40% by mass or more and 70% by mass or less of water-absorbing fibers in the second fiber layer, body fluids discharged from the wearer are more reliably absorbed by the water-absorbing fibers. Therefore, the nonwoven fabric has excellent liquid repellency when body fluids are repeatedly supplied.

[Aspect 9]
Injecting gas from the first fiber web side to a first fiber web made of heat-fusible fibers and a second fiber web including water-absorbing fibers and heat-fusible fibers, which are stacked in order in the thickness direction. The first step of
a second step of melting the surfaces of the heat-fusible fibers of the first fiber web and the heat-fusible fibers of the second fiber, and fusing the heat-fusible fibers to each other;
The first step includes injecting and absorbing the gas under conditions such that the amount of movement in the thickness direction of the heat-fusible fibers of the first fiber web is larger than the amount of movement in the width direction perpendicular to the machine direction. A method for producing nonwoven fabrics for sexual articles.

A first fibrous web made of heat-fusible fibers and a second fibrous web including water-absorbing fibers and heat-fusible fibers, which are stacked in the thickness direction, inject gas from the first fiber web side. In the first step, gas is injected under conditions such that the amount of movement of the heat-fusible fibers of the first fiber web in the thickness direction is larger than the amount of movement in the width direction orthogonal to the machine direction. can be formed. That is, the present manufacturing method provides a nonwoven fabric for an absorbent article comprising a first fiber layer and a second fiber layer in order in the thickness direction, the first fiber layer is made of heat-fusible fibers, and the first fiber layer is made of heat-fusible fibers, The second fiber layer includes water-absorbing fibers and heat-fusible fibers, and a portion of the heat-fusible fibers of the first fiber layer enters the second fiber layer and the heat-fusible fibers of the second fiber layer. It is possible to form a nonwoven fabric in which the water-absorbing fibers of the second fiber layer are fused to the heat-fusible fibers and are not exposed on the first surface.

Hereinafter, nonwoven fabrics for absorbent articles according to embodiments will be described in detail with reference to the drawings.

(Composition of absorbent article)
FIG. 1 is a diagram schematically showing an absorbent article 10 according to an embodiment, FIG. 2 is an end view schematically showing a cross section taken along line II-II in FIG. 1, and FIG. 3 is a partially enlarged sectional view of a topsheet. It is.

The absorbent article 10 shown in FIG. 1 is a sanitary napkin, and has a longitudinal direction L, a width direction W, and a thickness direction T that are orthogonal to each other, and has a main body part 12 extending in the longitudinal direction L, and approximately at the center of the longitudinal direction L. A pair of flap portions 14 extending on both sides in the width direction W are provided. Since the longitudinal direction L, width direction W, and thickness direction T of the absorbent article 10 coincide with the longitudinal direction L, width direction W, and thickness direction T of each material to be described later, hereinafter, the absorbent article 10 and A longitudinal direction L, a width direction W, and a thickness direction T are commonly used for each material. "Skin-facing surface side" and "non-skin-facing surface side" refer to the side that is relatively close to the skin surface of the wearer in the thickness direction T when the absorbent article 10 is worn by the wearer. Each refers to the far side, and is commonly used for each material of the absorbent article 10. In this specification, the "skin-facing surface" and "non-skin-facing surface" of the absorbent article 10 and each material (e.g., top sheet, absorbent body, back sheet, etc.) constituting the absorbent article 10 are used. The surface of the skin may be simply referred to as the "skin-facing surface" and the "non-skin-facing surface," respectively.

As shown in FIG. 2, the absorbent article 10 includes a topsheet 16, an absorbent core 18, and a backsheet 20 in order from the skin-facing surface in the thickness direction T. The top sheet 16 is a liquid permeable sheet located on the side facing the wearer's skin. The absorbent body 18 is a liquid-absorbing and liquid-retaining material located between the top sheet 16 and the back sheet 20. Examples of materials constituting the absorbent body 18 include pulp fibers, synthetic fibers, absorbent polymers, and the like. The back sheet 20 is a liquid-impermeable sheet located on the non-skin facing side of the wearer. Examples of the back sheet 20 include any liquid-impermeable sheet such as a liquid-impermeable nonwoven fabric, a synthetic resin film, a composite sheet thereof, and an SMS nonwoven fabric. An exterior sheet (not shown) may be laminated on the non-skin facing side of the backsheet 20 to reinforce the backsheet 20 and improve the feel. Examples of the exterior sheet include any water-repellent sheet, such as the same material as the back sheet 20, a water-repellent nonwoven fabric, a synthetic resin film, and a composite sheet thereof. The absorbent body 18, the top sheet 16, and the back sheet 20 are each bonded with an adhesive. As the bonding adhesive between the topsheet 16, the absorbent body 18, and the backsheet 20, a known material commonly used in the absorbent article 10, such as a thermoplastic adhesive, can be used.

(Top sheet)
Hereinafter, the top sheet 16 will be explained with reference to FIG. 3. The top sheet 16 is made of the nonwoven fabric according to this embodiment. The top sheet 16 has a longitudinal direction L, a width direction W, and a thickness direction T, and has a first surface 22 on one surface and a second surface 24 on the opposite side to the first surface 22. The first surface 22 and the second surface 24 each intersect with the thickness direction T. The first surface 22 and the second surface 24 according to this embodiment are each substantially flat. One direction of the thickness direction T is directed upward, and the other direction is directed downward.

The topsheet 16 includes a first fiber layer 26 and a second fiber layer 28 in the thickness direction T in the above order. The first fiber layer 26 is made of heat-fusible fibers and has a first surface 22 that is the skin-facing surface of the top sheet 16 (liquid-permeable sheet). The type of nonwoven fabric for the topsheet 16 is not particularly limited as long as it can be used for absorbent articles, but a thermal bond nonwoven fabric in which heat-fusible fibers are fused together is preferable, and an air-through nonwoven fabric is more preferable. preferable. The thickness of the topsheet 16 is, for example, 0.5 to 3.0 mm.

The basis weight of the first fiber layer 26 is generally uniform in the plane direction, and is, for example, 6 to 200 g/m ² . The heat-fusible fibers included in the first fiber layer 26 are fibers made of thermoplastic resin, such as olefin resin such as polyethylene (PE), polypropylene (PP), and ethylene-vinyl acetate copolymer (EVA); Known resins include polyester resins such as polyethylene terephthalate (PET) and polylactic acid (PLA); polyamide resins such as 6-nylon; these resins can be used alone or in combination with two or more types of resins. may be used together. The structure of the fibers made of such thermoplastic resin is not particularly limited, and examples include composite fibers such as core-sheath type fibers such as PET/PE, side-by-side type fibers, island/sea type fibers; hollow type Fibers include irregular cross-section fibers such as flat, Y-shaped, and C-shaped fibers, and fibers having these structures may be used alone or two or more types of fibers may be used in combination. The fineness of the heat-fusible fiber is, for example, 1 to 20 dtex.

The second fiber layer 28 includes water absorbent fibers and heat-fusible fibers, and has a second surface 24 that is the non-skin facing surface of the topsheet 16. The second fiber layer 28 preferably contains 40% by mass to 60% by mass of water-absorbing fibers. The water absorbent fibers are not exposed from the first surface 22.

The basis weight of the second fiber layer 28 is generally uniform in the plane direction, and is, for example, 6 to 200 g/m ² . Examples of the water-absorbing fibers included in the second fiber layer 28 include natural cellulose fibers such as pulp, cotton, and hemp; regenerated cellulose fibers such as rayon, lyocell, and cupro; One type of fiber may be used alone, or two or more types of fiber may be used in combination. The fineness of the water absorbent fibers is, for example, 0.5 to 5.0 dtex.

The heat-fusible fibers included in the second fiber layer 28 can be selected from the heat-fusible fibers exemplified in the first fiber layer 26, and are the same as the heat-fusible fibers of the first fiber layer 26. It may be different, or it may be different. The fineness of the thermoplastic resin fibers included in the second fiber layer 28 is, for example, 1 to 20 dtex. The fiber diameter of the heat-fusible fibers included in the second fiber layer 28 may be the same as or different from the fiber diameter of the heat-fusible fibers included in the first fiber layer 26.

The topsheet 16 may further include a third fiber layer 30 made of heat-fusible fibers on the second surface 24 side. That is, the topsheet 16 may include the first fiber layer 26, the second fiber layer 28, and the third fiber layer 30 in this order in the thickness direction T. The third fiber layer 30 may be made of the same material as the first fiber layer 26. The basis weight of the third fiber layer 30 is generally uniform in the plane direction, and is, for example, 6 to 200 g/m ² . The third fibrous layer 30 can have the same configuration as the first fibrous layer 26. The third fiber layer 30 is in contact with the second fiber layer 28 on the surface facing the skin. When the topsheet 16 includes the third fiber layer 30, the surface of the third fiber layer 30 on the non-skin facing side becomes the second surface 24, which is the non-skin facing surface of the topsheet 16.

The boundary between the first fiber layer 26 and the second fiber layer 28 and the boundary between the second fiber layer 28 and the third fiber layer 30 can be defined by the presence or absence of water-absorbing fibers. That is, in the cross section of the topsheet 16, the upper end in the thickness direction T where the water absorbent fibers are present is the boundary between the first fiber layer 26 and the second fiber layer 28, and the side where the water absorbent fibers are present is the boundary between the second fiber layer 28. , the side where no water-absorbing fibers are present may be used as the first fiber layer 26. Similarly, in the cross section of the topsheet 16, the lower end in the thickness direction T where the water absorbent fibers are present is the boundary between the second fiber layer 28 and the third fiber layer 30, and the side where the water absorbent fibers are present is the second fiber layer. 28. The third fiber layer 30 may be the side where no water-absorbing fibers are present. Although the boundary between the first fiber layer 26 and the second fiber layer 28 and the boundary between the second fiber layer 28 and the third fiber layer 30 defined in this way are linear in FIG. 3, the present invention The present invention is not limited to this, and the thickness direction T may be somewhat undulating. The water-absorbing fibers can be visually recognized by dyeing them using the method described below.

The thickness of the first fiber layer 26, that is, the height from the boundary between the first fiber layer 26 and the second fiber layer 28 to the first surface 22, is, for example, 0.3 to 2.0 mm. The skin-facing surface (the first surface 22 of the nonwoven fabric) of the first fiber layer 26 has no concave portion recessed in the thickness direction T. In this specification, a concavity is one that is intentionally formed by bending or moving the fibers by gear processing or spraying an air jet, and is a concave part that is formed intentionally by bending or moving the fibers, such as by gear processing or spraying an air jet, and is a concave part that is formed intentionally by bending or moving the fibers. Does not include undulations formed in In the height from the boundary between the first fiber layer 26 and the second fiber layer 28 to the first surface 22, the minimum height is preferably 50% or more of the maximum height, and more preferably 70% to 95% or less. preferable. The thickness of the second fiber layer 28, that is, the height from the boundary between the first fiber layer 26 and the second fiber layer 28 to the boundary between the second fiber layer 28 and the third fiber layer 30, is, for example, 0.2. ~1.0mm is mentioned. The thickness of the third fiber layer 30, that is, the height from the boundary between the second fiber layer 28 and the third fiber layer 30 to the second surface 24, is, for example, 0.2 to 0.5 mm.

Some of the heat-fusible fibers of the first fiber layer 26 are fused to some of the heat-fusible fibers of the second fiber layer 28 within the second fiber layer 28 . That is, some of the heat-fusible fibers of the first fiber layer 26 bend toward the second fiber layer 28 side in the thickness direction T, enter the second fiber layer 28, and become heat-fusible fibers contained in the second fiber layer 28. It comes in contact with some of the sex fibers and is fused.

A further part of the heat-fusible fibers of the first fiber layer 26 that have entered the second fiber layer 28 are contained in the third fiber layer 30. It is fused with. That is, a part of the heat-fusible fibers of the first fiber layer 26 bends toward the second fiber layer 28 side in the thickness direction T and enters the second fiber layer 28, and furthermore, a part of the heat-fusible fibers of the first fiber layer 26 bend toward the second fiber layer 28 side in the thickness direction T and enter the second fiber layer 28. 28, enters the third fiber layer 30, contacts some of the heat-fusible fibers of the third fiber layer 30, and is fused.

Some of the heat-fusible fibers of the second fiber layer 28 are fused to some of the heat-fusible fibers of the third fiber layer 30 within the third fiber layer 30 . That is, some of the heat-fusible fibers of the second fiber layer 28 bend toward the third fiber layer 30 side in the thickness direction T, enter the third fiber layer 30, and become heat-fusible fibers included in the third fiber layer 30. It comes in contact with some of the sex fibers and is fused.

(Production method)
Hereinafter, a method for manufacturing the topsheet 16 will be described with reference to FIG. 4. FIG. 4 is a schematic diagram showing the manufacturing process of the top sheet 16 including the first fiber layer 26 and the second fiber layer 28. The top sheet 16 is produced through a first step, a second step, a third step, and a fourth step. In FIG. 4, MD indicates the machine direction (conveyance direction).

In the first step, heat-fusible fibers and water-absorbing fibers are supplied to the first card machine 32 to form a second fiber web 34. In the second step, the heat-fusible fibers are supplied to the second card machine 36 to form the first fiber web 38. The first fiber web 38 is stacked on the second fiber web 34 to obtain a laminated web 40. The laminated web 40 is transported to the third step.

In the third step, first, the laminated web 40 is placed on the circumferential surface of the suction drum 42. The suction drum 42 includes a fixed inner cylinder 44 and an air permeable outer cylinder 46 that is concentric with the inner cylinder 44 and rotates in the machine direction MD. The suction drum pressure measured with a pressure gauge is appropriately selected depending on the basis weight of each fiber web and the flow rates of the first air and second air, which will be described later. It is preferably 5 to 8 kPa, and more preferably 5 to 8 kPa. The laminated web 40 is placed on the circumferential surface of the outer cylinder 46 and conveyed together with the outer cylinder 46 in the machine direction MD at a predetermined speed, for example, 100 m/min. Inner cylinder 44 has a suction area 48 . Above the suction region 48, there is a first manifold 50 having a plurality of nozzles arranged in the cross direction CD perpendicular to the machine direction MD, and a second manifold 50 having a plurality of nozzles arranged parallel to the first manifold 50 and arranged in the cross direction CD. A manifold 52 is provided. The nozzle has a predetermined opening diameter, for example 1 mm in diameter. The first manifold 50 injects first air made of heated gas at, for example, 200° C. toward the laminated web 40 . The flow rate of the first air injected from the first manifold 50 is, for example, 3 to 5 m ³ /min. Subsequently, the second manifold 52 injects second air made of heated gas at, for example, 200° C. toward the laminated web 40 . The flow rate of the second air injected from the second manifold 52 is, for example, 3 to 5 m ³ /min.

In the laminated web 40, the heat-fusible fibers of the first fibrous web 38 located directly under the first manifold 50 and the second manifold 52 move as the first air and the second air are sequentially injected. By setting the flow rate of the first air and the second air to 3 to 5 m ³ /min, the heat-fusible fibers of the first fiber web 38 move more in the thickness direction than in the width direction W (crossing direction CD). The amount of movement of T increases. In other words, the first air and the second air are injected under the condition that the amount of movement in the thickness direction T is larger than the amount of movement in the cross direction CD (width direction W) perpendicular to the machine direction MD. As a result, the heat-fusible fibers of the first fibrous web 38 hardly move in the width direction W, and some of them bend toward the second fibrous web 34 side in the thickness direction T and enter the second fibrous web 34 .

The surface of the first fibrous web 38 moves less in the width direction W and is pressed in the thickness direction T due to the injection of the first air and second air under the predetermined conditions. This can result in a smoother surface structure with fewer irregularities. Therefore, the top sheet 16 can be formed by disposing the first fiber layer 26 based on the first fiber web on the skin side.

In the fourth step, the laminated web 40 passes through the dryer 54. The dryer 54 blows heated air onto the laminated web 40 at a temperature that can melt the surface of the heat-fusible fibers, for example, 120° C. to 150° C. In the laminated web 40, heat-fusible fibers are fused together. As described above, some of the heat-fusible fibers of the first fiber web 38 have entered the second fiber web 34, so that the heat-fusible fibers contained in the second fiber web 34 are absorbed into the second fiber web 34. Welds with some of the sex fibers.

By cooling the laminated web 40 conveyed from the dryer 54 to room temperature, a topsheet 16 that can be used for absorbent articles is obtained. The topsheet (nonwoven fabric) 16 obtained as described above is an air-through nonwoven fabric, and therefore has excellent bulkiness.

The top sheet 16 including the third fiber layer 30 is prepared by supplying heat-fusible fibers to a carding machine (not shown) prior to the first step, forming a third fiber web, and disposing the first fiber layer on the third fiber web. The second fibrous web 34 formed in the step is overlapped, and the first fibrous web 38 formed in the second step is further overlapped to form a laminated web. The top sheet 16 including the first fiber layer 26, the second fiber layer 28, and the third fiber layer 30 is obtained by subjecting the laminated web to the third step and the fourth step.

(action and effect)
The absorbent article 10 is worn with the top sheet 16 placed on the side facing the wearer's skin. Body fluids discharged from the wearer are supplied to the top sheet 16. The body fluid migrates from the first surface 22 to the first fibrous layer 26 in the thickness direction T. The body fluid is drawn further into the interior by the water absorbent fibers from the first fiber layer 26 to the second fiber layer 28, and a portion of the body fluid is absorbed by the water absorbent fibers. The body fluid drawn in and absorbed by the water-absorbing fibers is absorbed by the topsheet 16 and the absorbent body 18 disposed on the non-skin side.

The topsheet 16 is for an absorbent article that includes a first fiber layer 26 and a second fiber layer 28 in order in the thickness direction T, and the first fiber layer 26 has a skin-facing surface and is heat-fusible. The second fiber layer 28 includes water-absorbent fibers and heat-fusible fibers, and a portion of the heat-fusible fibers of the first fiber layer 26 enters the second fiber layer 28 and forms the second fiber layer 28. The water-absorbing fibers of the second fiber layer 28 are not exposed to the skin-facing surface because they are fused to some of the heat-fusible fibers of the fiber layer 28 .

In the topsheet 16, some of the heat-fusible fibers of the first fiber layer 26 and some of the heat-fusible fibers of the second fiber layer 28 are fused together. That is, some of the heat-fusible fibers of the first fiber layer 26 bend toward the second fiber layer 28 side in the thickness direction T, enter the second fiber layer 28, and become heat-fusible fibers contained in the second fiber layer 28. It comes in contact with some of the sex fibers and is fused. Therefore, in the topsheet 16, since the first fiber layer 26 and the second fiber layer 28 are firmly joined, delamination between the first fiber layer 26 and the second fiber layer 28 can be suppressed.

The water-absorbing fibers of the second fiber layer 28 are formed by a portion of the heat-fusible fibers of the first fiber layer 26 and a portion of the heat-fusible fibers of the second fiber layer 28, which are fused to each other. Retained within layer 28. Therefore, in the topsheet 16, the fibers of the second fiber layer 28 are prevented from coming off.

Since the body fluid supplied to the skin-facing surface is transferred from the skin-facing surface to the inside of the first fiber layer 26 by the heat-fusible fibers of the first fiber layer 26, the body fluid is unlikely to remain on the skin-facing surface of the top sheet 16. Therefore, the top sheet 16 has excellent liquid permeability. The top sheet 16 is an air-through nonwoven fabric. For this reason, the top sheet 16 has excellent bulkiness and therefore excellent liquid permeability.

Since the water-absorbing fibers are not exposed on the skin-facing surface, the body fluid that has migrated into the first fiber layer 26 further migrates in the thickness direction T, and is transferred to the interface between the first fiber layer 26 and the second fiber layer 28. reach. The body fluid smoothly transfers to the second fiber layer 28 because some of the heat-fusible fibers of the first fiber layer 26 have entered the second fiber layer 28. The body fluid transferred to the second fiber layer 28 is absorbed by the water-absorbing fibers included in the second fiber layer 28. The body fluid absorbed by the water absorbent fibers is absorbed by the absorbent body 18 placed on the non-skin side. In this way, the top sheet 16 smoothly transfers the body fluid supplied to the skin-facing surface from the first fiber layer 26 to the second fiber layer 28 and absorbs it with the water-absorbing fibers of the second fiber layer 28. , excellent liquid drainage.

As a result, the topsheet 16 can suppress delamination between the first fiber layer 26 and the second fiber layer 28, and has excellent liquid permeability and liquid drainage.

In this specification, liquid permeability refers to the time required for bodily fluids to permeate into the top sheet 16 from the skin-facing surface, and liquid drainage refers to the time required for body fluids to drain from the skin-facing surface to the non-skin-facing surface from within the top sheet 16. It is evaluated based on the time it takes for it to disappear.

If the first surface of the first fiber layer is the skin-facing surface and a recessed portion is formed in the skin-facing surface in the thickness direction, the recessed portion will absorb the water absorbency contained in the second fiber layer from the skin-facing surface. The distance to the fiber is short. In other words, since the water-absorbing fibers that have absorbed body fluids are located close to the skin-facing surface, the fluids supplied to the skin-facing surface do not migrate in the thickness direction and accumulate in the recesses, resulting in a decrease in liquid permeability. will decrease.

Since the top sheet 16 of the present embodiment does not have a concave portion recessed in the thickness direction T on the skin-facing surface, body fluids are prevented from accumulating in specific locations. Therefore, the top sheet 16 has excellent liquid permeability.

In the topsheet 16, the basis weight of the second fiber layer 28 is uniform in the surface direction. Since the basis weight of the second fiber layer 28 is uniform in the surface direction, body fluids supplied to the skin-facing surface and transferred in the thickness direction T are uniformly absorbed regardless of the position in the surface direction. Therefore, the top sheet 16 can provide excellent liquid repellency regardless of its position in the surface direction.

Since the topsheet 16 contains water-absorbing fibers in the second fiber layer 28 in an amount of 40% by mass or more and 70% by mass or less, the body fluids discharged from the wearer are more reliably absorbed by the water-absorbing fibers. Therefore, the top sheet 16 has excellent liquid repellency when body fluids are repeatedly supplied.

When the third fiber layer 30 made of heat-fusible fibers is provided on the non-skin side of the second fiber layer 28, the second fiber layer 28 is covered with the third fiber layer 30, and the water-absorbing fibers are on the non-skin facing side. Exposure is suppressed. Therefore, in the top sheet 16, the water-absorbing fibers are prevented from coming off.

A further part of the heat-fusible fibers of the first fiber layer 26 that have entered the second fiber layer 28 penetrate the second fiber layer 28 and enter the third fiber layer 30. It may be fused with a part of the heat-fusible fibers. That is, a part of the heat-fusible fibers of the first fiber layer 26 bends toward the second fiber layer 28 side in the thickness direction T and enters the second fiber layer 28, and furthermore, a part of the heat-fusible fibers of the first fiber layer 26 bend toward the second fiber layer 28 side in the thickness direction T and enter the second fiber layer 28. 28, enters the third fiber layer 30, and is fused to some of the heat-fusible fibers of the third fiber layer 30. Therefore, since the topsheet 16 is firmly bonded not only between the first fiber layer 26 and the second fiber layer 28 but also between the second fiber layer 28 and the third fiber layer 30, delamination can be suppressed.

The water-absorbing fibers of the second fiber layer 28 include a portion of the heat-fusible fibers of the first fiber layer 26 and a portion of the heat-fusible fibers of the second fiber layer 28, which are fused to each other, and the second fibers. A further portion of the heat-fusible fibers of the first fiber layer 26 and a portion of the heat-fusible fibers of the third fiber layer 30 penetrate the layer 28 and are retained within the second fiber layer 28 . Therefore, in the topsheet 16, the loss of fibers from the second fiber layer 28 is further suppressed.

Some of the heat-fusible fibers of the second fiber layer 28 enter the third fiber layer 30 , and further part of the heat-fusible fibers of the first fiber layer 26 and the heat-fusible fibers of the third fiber layer 30 enter the third fiber layer 30 . It may be fused to a part of the fiber. That is, some of the heat-fusible fibers of the second fiber layer 28 bend toward the third fiber layer 30 side in the thickness direction T and enter the third fiber layer 30. Further, some of the heat-fusible fibers of the first fiber layer 26 are fused with some of the heat-fusible fibers of the fiber layer 30 and further penetrate the second fiber layer 28 and enter the third fiber layer 30. Some parts are fused. Therefore, in the topsheet 16, the second fibrous layer 28 and the third fibrous layer 30 are more firmly joined, so that delamination can be further suppressed.

The water-absorbing fibers of the second fiber layer 28 are a part of the heat-fusible fibers of the second fiber layer 28 and a part of the heat-fusible fibers of the third fiber layer 30, which are fused to each other, and The heat-fusible fibers of the first fiber layer 26 and the second fiber layer 28 are held within the second fiber layer 28 by a further portion of the heat-fusible fibers that have penetrated the fiber layer 28 . Therefore, in the topsheet 16, the loss of fibers from the second fiber layer 28 is further suppressed.

(Modified example)
The present invention is not limited to the embodiments described above, and can be modified as appropriate within the scope of the gist of the present invention. For example, the top sheet 60 shown in FIG. 5 may have irregularities. That is, the top sheet 60 has a plurality of solid convex portions 62 on the first surface 22 that protrude in the direction from the second surface 24 toward the first surface 22 and a plurality of convex portions 62 that are solid and protrude in the direction from the first surface 22 toward the second surface 24. It has a plurality of depressed recesses 64. In this specification, "solid" means that there is no space where the fiber density is significantly lower than the surrounding area, which would impede the movement of liquid within the convex portion 62. If d is the difference in height between the highest part of the first surface 22 with the highest height and the lowest part of the first surface 22 with the lowest height, above the position d/2 height from the deepest part The portion that protrudes to the side can be referred to as a convex portion 62, and the portion that is recessed downward can be referred to as a concave portion 64. The surface sheet 60 having irregularities may be formed by further performing a gear processing step after the fourth step in the above manufacturing method. In the gear processing step, the nonwoven fabric in which the first fiber layer 26, the second fiber layer 28, and the third fiber layer are joined is sandwiched between a pair of gear processing rolls and locally pressed, thereby forming a plurality of recesses 64. can be formed to obtain the topsheet 60.
Although not shown, the topsheet 60 may include a compressed portion. The compressed parts are arranged intermittently along the longitudinal direction L in the recessed part 64. The compressed parts may be arranged at equal intervals in the longitudinal direction L in the recessed part 64, or may be arranged at non-equal intervals. In the recesses 64 adjacent in the width direction W, the positions may be the same in the longitudinal direction L, or may be at different positions. The compressed portion is formed by being sandwiched between the upper part of the first fiber layer 26 and the lower part of the third fiber layer 30 disposed with the second fiber layer 28 in between in the thickness direction T. The fiber layer 28 and the third fiber layer 30 are joined.

The type and use of the absorbent article 10 are not particularly limited, and include, for example, sanitary and sanitary products such as panty liners, disposable diapers (tape type, pants type), incontinence pads, sweat sheets, etc. The target may be a human or a non-human animal such as a pet. The liquid to be absorbed by the absorbent article 10 is not particularly limited, and examples thereof include liquid excrement and body fluids of the wearer.

In the above embodiment, a case has been described in which the first fiber layer is arranged on the skin side, but the present invention is not limited to this. For example, the nonwoven fabric may be applied to the topsheet with the first fiber layer disposed on the non-skin side and the second or third fiber layer disposed on the skin side. That is, the second surface is the skin-facing surface. In this case, the nonwoven fabric includes a first fiber layer made of heat-fusible fibers and a second fiber layer containing water-absorbing fibers and heat-fusible fibers, so it is bulky and has excellent liquid permeability. The water-absorbing fibers of the second fiber layer are not exposed to the first surface, so they are difficult to fall off from the first surface.

(Measuring method)
<Basic weight, thickness, fiber density and fineness of top sheet>
The basis weight, thickness, fiber density, and fineness of the top sheet in the above embodiment are measured by the following method.
(1) Basis weight of top sheet: A sample is cut out from the top sheet into an appropriate size, for example, 10 cm x 10 cm, and the mass is measured after leaving it in an atmosphere of 20° C. and 65% humidity for 24 hours. Calculate the basis weight of the sample by dividing the measured mass by the area of the sample. The average value of the basis weights of 10 samples is taken as the basis weight of the top sheet.
(2) Thickness of top sheet: 15cm ² Using a thickness gauge (Model FS-60DS manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), measuring load of 3gf/cm ² (0.3kPa) Measure the thickness of the top sheet under the following conditions. The thickness of one sample is measured at three locations, and the average value of the three locations is defined as the thickness of the top sheet.
(3) Fiber density of the top sheet: The fiber density of the top sheet is calculated by dividing the weight of the top sheet determined by the above method by the thickness of the top sheet determined by the above method.
(4) Fiber fineness: The fiber fineness is determined by measuring the cross-sectional area of the fiber by enlarging the cross-sectional shape of the target fiber using a scanning electron microscope. Calculated from the specific gravity of the fiber components.

<Thickness of each part>
The thickness of each part of the first fiber layer, second fiber layer, and third fiber layer of the topsheet is measured by the following method. First, the hydrophilic fibers are dyed, and then the thickness of each part is measured. Dyeing of hydrophilic fibers is carried out using the following procedure. (1) Prepare the top sheet whose thickness is to be measured. (2) Pour 1L of water into a pot and heat to 60°C to 70°C. (3) Put the reagent Kayastain Q (Shokusensha Co., Ltd.) into the pot of (2) and dissolve. (4) Heat the pot to 80℃. (5) Place the top sheet into the pot from (4) and leave it for 30 minutes. (5) After that, wash the top sheet with running water. (6) Dry in an oven at 80°C for 1 hour. As a result of the above procedure, the absorbent fiber (rayon) is dyed blue and the heat-fusible fiber (PET) is dyed yellow.
The thickness is measured using the following procedure. (1) The dyed surface sheet is cut out to a length of 5 mm in the machine direction (MD) and 20 mm in the cross direction (CD) to prepare a sample. (2) Fix the sample to a jig with double-sided tape so that the CD cross section can be observed. (3) Take an enlarged photograph of the cross section with a digital microscope VHX-7000 manufactured by Keyence Corporation, select the distance between two points for planar measurement, and Measure the thickness of each part of the fiber layer.

<Water-absorbing fiber content>
The content of the water absorbent fibers in the second fiber layer can be obtained as follows. (1) After cutting out a sample in the target area from a top sheet that has been dried in advance at 105° C. for 1 hour, the initial mass (g) of the sample is measured. (2) The sample is immersed in 70% sulfuric acid for 1 hour to dissolve the water absorbent fibers. (3) After immersing in sulfuric acid, the sample is washed with about 6 liters of water while suctioning it on a Buchner funnel, and then further washed with about 1 liter of pure water. (4) After drying the washed sample at 105° C. for 2 hours, the processed mass (g) of the sample is measured. (5) Calculate the water-absorbent fiber content mass (g) in the sample by subtracting the processed mass of the sample from the initial mass of the sample, and then calculate the obtained water-absorbent fiber content mass per unit planar area. The content of water-absorbing fibers can be obtained by converting to the mass of .

(Example)
A nonwoven fabric corresponding to the topsheet according to the above embodiment was produced and evaluated. The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

(A) Sample According to the above-mentioned manufacturing method, PE/PET core-sheath type fibers were used as heat-fusible fibers, and fibers made of rayon were used as water-absorbing fibers, and the first fiber layer, second fiber layer, and A nonwoven fabric according to Example 1 having three fiber layers was produced. The flow rate of the first air and the second air in the third step was 5 m ³ /min, and the suction drum pressure was 5.6 kPa. The temperature of the heated air in the fourth step was 136°C. The specific configuration is as shown in Table 1.

As a comparative example, a nonwoven fabric of Comparative Example 2 was produced in the same manner as in the above example except that the third and fourth steps in the above manufacturing method were not performed and the hydroentangling method was used.

Further, as a reference example, a nonwoven fabric of Reference Example 1 was produced in the same manner as in the above example except that the third step in the above manufacturing method was not performed. Further, it is provided with a first fiber layer made of PE/PET core-sheath type fibers, and a second fiber layer containing cotton as a water-absorbing fiber and thermoplastic resin fibers of PE/PET core-sheath type fibers, and manufactured as described above. A reference example in which the first surface has an uneven structure by injecting an air jet with a flow rate of 9 m ³ /min of the first air and second air in the third step of the method and setting the suction drum pressure to 8.6 kPa. A nonwoven fabric of No. 2 was produced. A nonwoven fabric of Reference Example 1 was produced through the same steps as in the above example except that a concavo-convex structure was formed. Microscopic photographs of cross sections of the obtained nonwoven fabric are shown in FIGS. 6 to 9.

(B) Evaluation method Various tests were conducted according to the following procedures.

(Liquid permeability and liquid drainage test)
(1) A sample cut into a size of 200 mm x 100 mm and an acrylic plate having the same size as the sample and a through hole of 40 mm x 10 mm in the center were prepared.
(2) An acrylic plate was placed on the center of the surface of the sample on the first fiber layer side.
(3) A stopwatch was started at the same time as 2 ml of horse blood was dropped using a micropipette.
(4) The time required for horse blood to disappear from the sample and around the holes in the acrylic plate (transmission time) was measured.
(5) Continuously, the time until the horse blood in the acrylic plate was separated (liquid separation time) was measured.
(6) 30 seconds after the start of the measurement, 2 ml of the second horse blood was dropped (the second measurement was started even if the first horse blood was not completely drained).
(7) The measurements in (4) and (5) above were carried out in order.
(8) 60 seconds after the start of the measurement, remove the acrylic plate, and 90 seconds after the start of the measurement, add 10 pieces of pre-weighed filter paper (35mm x 50mm) and a weight (35mm x 50mm, 525g) to the area where horse blood was dropped. I posted it.
(9) After 60 seconds, the weight was removed and the weight of the filter paper was measured.

(10) Subtract the mass of the filter paper before placing it on the sample from the mass of the filter paper after placing it on the sample to find the rewet (g), and find the ratio to the amount of horse blood absorbed (2 ml≒2 g). Ta(%).

(Fiber shedding test)
(1) After drying the membrane filter in an oven at 90° C. for 1 hour, it was left to cool in a desiccator for 30 minutes.
(2) Five samples cut out to a size of 100 mm x 100 mm were prepared.
(3) Five 300 ml beakers containing 300 ml of tap water were prepared.
(4) A rotor was placed in a beaker and stirred using a magnetic stirrer.
(5) Fold the sample into an inverted conical shape with the smoother surface facing outward.
(6) The sample from (5) was gently dropped into the center of the water surface of the beaker and a stopwatch was started when the sample touched the center of the water surface.
(7) After stirring for 10 minutes, the sample was taken out.
Operations (4) to (7) were performed for each sample.
(8) The weight of the membrane filter in (1) was measured.
(9) A membrane filter was placed on top of the suction bottle, and a funnel was placed on it and fixed with a holder.
(10) Ethanol was added from the funnel to moisten the membrane filter, and the vacuum pump was turned on to suck it.
(11) Water from the stirred beaker was poured into the funnel and suctioned.
(12) Once the water in the stirred beaker was suctioned, first remove the hose connected to the suction bottle and turn off the vacuum pump.
(13) The funnel was removed and the membrane filter with accumulated fibers was taken out into a Petri dish.
(14) The petri dish was covered with plastic wrap to allow air to enter, and the time was written on the plastic wrap.
(15) The membrane filter of (14) was dried in an oven at 90° C. for 1 hour, left to cool in a desiccator for 30 minutes, and then weighed.
Operations (9) to (15) were performed for each sample.
(16) The average value of the measured weights (n=5) was defined as the amount of fiber shedding (mg/m ² ).

(C) Evaluation Results As shown in Table 1, the nonwoven fabric according to Example 1 had excellent results in terms of liquid permeability and liquid drainage in both the first and second tests. Furthermore, it was confirmed that the nonwoven fabric according to Example 1 had excellent rewetting properties.

Since the nonwoven fabric according to Comparative Example 1 was produced by a hydroentangling method, it had a low bulk, resulting in poor liquid permeability, and the presence of water-absorbing fibers on the surface, resulting in poor liquid repellency.

In comparison with Example 1, Reference Example 1 was inferior in liquid removal properties and rewet properties, and had a large amount of fibers falling off. Since the nonwoven fabric according to Reference Example 1 did not undergo the third step in the manufacturing method of the above embodiment, it is considered that the liquid could not smoothly transfer from the first fiber layer to the second fiber layer. Furthermore, in the nonwoven fabric of Reference Example 1, it is thought that the amount of fibers falling off increased because the water-absorbing fibers were difficult to be retained in the second fiber layer.

It is thought that the nonwoven fabric according to Reference Example 2 had a concavo-convex structure formed on the first surface by spraying an air jet, which caused liquid to easily accumulate in the concave portions, resulting in poor liquid permeability and liquid drainage.

10 Absorbent article 12 Main body portion 14 Flap portion 16 Top sheet (nonwoven fabric)
18 Absorber 20 Back sheet 22 First surface (skin facing surface)
24 Second surface (non-skin facing surface)
40 Laminated web 42 Suction drum 44 Inner tube 46 Outer tube 48 Suction area 54 Dryer 60 Top sheet 62 Convex portion 64 Concave portion CD Cross direction MD Machine direction L Longitudinal direction T Thickness direction W Width direction

Claims (9)

A nonwoven fabric for an absorbent article comprising a first fiber layer and a second fiber layer in order in the thickness direction,
The first fiber layer has a first surface and is made of heat-fusible fibers,
The second fiber layer includes water-absorbing fibers and heat-fusible fibers,
Some of the heat-fusible fibers of the first fiber layer enter the second fiber layer and are fused with some of the heat-fusible fibers of the second fiber layer,
The water absorbent fibers of the second fiber layer are nonwoven fabrics that are not exposed on the first surface. The nonwoven fabric according to claim 1, wherein the first fiber layer has no recesses formed in the thickness direction on the first surface. The nonwoven fabric according to claim 1, further comprising a third fiber layer made of heat-fusible fibers on the opposite side of the second fiber layer to the first fiber layer. A further part of the heat-fusible fibers of the first fiber layer that have entered the second fiber layer penetrate the second fiber layer, enter the third fiber layer, and form the third fiber layer. 4. The nonwoven fabric according to claim 3, wherein the nonwoven fabric is fused to a portion of the heat-fusible fibers of the layer. Some of the heat-fusible fibers of the second fiber layer enter the third fiber layer, and a further part of the heat-fusible fibers of the first fiber layer and the heat-fusible fibers of the third fiber layer enter the third fiber layer. The nonwoven fabric according to claim 4, wherein the nonwoven fabric is fused to a part of the adhesive fibers. The nonwoven fabric according to claim 1, wherein the first surface of the first fiber layer is a skin-facing surface. The nonwoven fabric according to claim 6, wherein the second fiber layer has a uniform basis weight in a plane direction. The nonwoven fabric according to claim 6, wherein the second fiber layer contains the water-absorbing fibers in an amount of 40% by mass or more and 70% by mass or less. Injecting gas from the first fiber web side to a first fiber web made of heat-fusible fibers and a second fiber web including water-absorbing fibers and heat-fusible fibers, which are stacked in order in the thickness direction. The first step of
a second step of melting the surfaces of the heat-fusible fibers of the first fiber web and the heat-fusible fibers of the second fiber web, and fusing the heat-fusible fibers together;
The first step includes injecting and absorbing the gas under conditions such that the amount of movement in the thickness direction of the heat-fusible fibers of the first fiber web is larger than the amount of movement in the width direction perpendicular to the machine direction. A method for producing nonwoven fabrics for sexual articles.

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