JP7581111B2 - Sheet for absorbent article and absorbent article including same - Google Patents

Description

The present invention relates to a sheet for absorbent articles. The present invention also relates to an absorbent article equipped with the sheet for absorbent articles.

There is a known technology for using a nonwoven fabric having an uneven surface as a component of an absorbent article. For example, Patent Document 1 describes a laminated material composed of a first substantially non-stretchable layer and a second layer. The second layer and the first layer are attached by a plurality of spaced adhesive regions. As a result, the laminated material has a plurality of adhesive regions and non-adhesive regions, and a bulky pillow portion is formed in the laminated material. This laminated material is used as a back sheet of an absorbent article.

Patent Document 2 describes how a honeycomb pattern (hexagonal concave pattern) is imparted to a spunbond-meltblown-meltblown-spunbond nonwoven fabric by embossing, with the center of the pattern raised. This nonwoven fabric is used as a leg cuff for an absorbent article.

Japanese Patent Application Publication No. 6-255006 JP 2004-129810 A

As described above, the nonwoven fabrics described in Patent Documents 1 and 2 are used as components of absorbent articles that require leakproofing. However, the nonwoven fabrics described in these documents do not have sufficient leakproofing properties in situations where liquid leakage is likely to occur, such as when a wearer moves while wearing the absorbent article.
SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a sheet for absorbent articles which can overcome the above-mentioned drawbacks of the prior art.

The present invention relates to a sheet for absorbent articles comprising a plurality of nonwoven fabric layers laminated together,
At least one surface of the sheet has a concave-convex structure,
The present invention provides a sheet for absorbent articles that has water repellency against a liquid having a surface tension of 60 mN/m.

The absorbent sheet of the present invention is highly leak-proof, even though it is made of nonwoven fabric. Therefore, even if a wearer moves around while wearing an absorbent article equipped with this absorbent sheet, liquid is unlikely to seep through the absorbent sheet.

FIG. 1 is an explanatory diagram showing the width, pitch and height of protrusions in an absorbent article sheet of the present invention. FIG. 2 is a perspective view showing one embodiment of the sheet for absorbent articles of the present invention. FIG. 3 is a perspective view showing another embodiment of the sheet for absorbent articles of the present invention. 4(a) to (c) are schematic diagrams showing the cross-sectional structure in the thickness direction of the absorbent article sheet of the present invention. FIG. 5 is a schematic diagram showing a cross-sectional structure in the thickness direction of the absorbent article sheet of the present invention. 6(a) and (b) are schematic diagrams showing the cross-sectional structure in the thickness direction of the absorbent article sheet of the present invention. 7(a) and (b) are schematic diagrams showing the cross-sectional structure in the thickness direction of the absorbent article sheet of the present invention. FIG. 8 is a schematic diagram showing a cross-sectional structure in the thickness direction of the absorbent article sheet of the present invention. 9(a) and (b) are schematic diagrams showing the cross-sectional structure in the thickness direction of the absorbent article sheet of the present invention. FIG. 10 is a schematic diagram showing a cross-sectional structure in the thickness direction of the absorbent article sheet of the present invention. FIG. 11 is a schematic diagram showing an example of a suitable apparatus used for producing the absorbent article sheet of the present invention. FIG. 12 is a schematic diagram showing an example of another preferred apparatus used for producing the absorbent article sheet of the present invention. 13(a) to (d) are schematic diagrams showing an example of another suitable apparatus used for producing the absorbent article sheet of the present invention, and schematic diagrams showing the sheet production process using the apparatus. 14(a) to (e) are schematic diagrams showing an example of another suitable apparatus used for producing the absorbent article sheet of the present invention, and schematic diagrams showing the sheet production process using the apparatus. FIG. 15 is a schematic diagram showing an example of another preferred apparatus used for producing the absorbent article sheet of the present invention. FIG. 16 is a schematic diagram showing an example of another preferred apparatus used for producing the absorbent article sheet of the present invention.

The present invention will now be described based on its preferred embodiments.
The sheet for absorbent articles of the present invention (hereinafter, also simply referred to as "sheet") is a fiber sheet composed of a nonwoven fabric. The sheet of the present invention is used as a constituent member of an absorbent article. The sheet of the present invention is a fiber sheet and does not have a film of a liquid-impermeable layer.
The absorbent article using the sheet of the present invention generally has a vertically elongated shape with a longitudinal direction corresponding to the direction extending from the wearer's abdominal side through the crotch region to the dorsal side and a width direction perpendicular to the longitudinal direction. The absorbent article has a crotch portion disposed in the crotch region of the wearer, and abdominal and dorsal portions extending in front and behind the crotch portion. The crotch portion has an excretory portion-facing portion that is disposed facing the excretory portion of the wearer when the absorbent article is worn, and the excretory portion-facing portion is usually located in the longitudinal center of the absorbent article or in the vicinity thereof.

Absorbent articles generally comprise a top sheet located on the wearer's skin-facing side, a back sheet located on the non-skin-facing side, and an absorbent interposed between the two sheets. The top sheet can be a liquid-permeable sheet, such as a nonwoven fabric or a perforated film. The skin-facing side of the top sheet may be uneven. For example, a plurality of scattered convex portions can be formed on the skin-facing side of the top sheet. Alternatively, ridges and grooves extending in one direction can be formed alternately on the skin-facing side of the top sheet. For such purposes, the top sheet can be formed using two or more sheets of nonwoven fabric. On the other hand, the back sheet can be made of a nonwoven fabric that is poorly permeable to liquids, for example.

The absorbent body has an absorbent core. The absorbent core is composed of, for example, a stack of hydrophilic fibers such as cellulose including pulp, a mixed stack of the hydrophilic fibers and an absorbent polymer, a stack of absorbent polymer, a laminated structure in which an absorbent polymer is supported between two absorbent sheets, or the like. At least the skin-facing surface of the absorbent core may be covered with a liquid-permeable core wrap sheet, or the entire surface including the skin-facing surface and the non-skin-facing surface may be covered with the core wrap sheet. As the core wrap sheet, for example, tissue paper made of hydrophilic fibers or liquid-permeable nonwoven fabric can be used. As described later, the sheet of the present invention is preferably used as a back sheet.

In addition to the above-mentioned top sheet, back sheet and absorbent body, depending on the specific use of the absorbent article, leakage prevention cuffs extending along the longitudinal direction may be arranged on both sides along the longitudinal direction of the skin-facing side. The leakage prevention cuffs generally have a base end and a free end. The leakage prevention cuffs have a base end on the skin-facing side of the absorbent article and stand up from the skin-facing side. The leakage prevention cuffs are made of a liquid-resistant or water-repellent material and are breathable. The sheet of the present invention is preferably used as leakage prevention cuffs. An elastic member made of rubber thread or the like may be arranged in a stretched state at or near the free end of the leakage prevention cuff. When the absorbent article is worn, this elastic member contracts, causing the leakage prevention cuffs to stand up toward the wearer's body, effectively preventing liquid excreted on the top sheet from leaking out along the top sheet to the outside of the width direction of the absorbent article.

The absorbent article may further have an adhesive layer on the non-skin-facing surface. The adhesive layer is used to secure the absorbent article to underwear or another absorbent article when the absorbent article is worn.

Examples of absorbent articles having the above configuration include, but are not limited to, flat-type disposable diapers, pants-type disposable diapers, sanitary napkins, and incontinence pads.

Due to its high leak-proofing properties, the sheet of the present invention is suitable for use as a component of an absorbent article that requires leak-proofing. For example, the sheet of the present invention can be used as a back sheet. Or, the sheet of the present invention can be used as a leak-proof cuff.

The sheet of the present invention has a structure in which a plurality of nonwoven fabric layers are laminated. Furthermore, it is preferable that at least one surface of the sheet of the present invention has an uneven structure.
One of the features of the sheet of the present invention is its high water repellency. In detail, the sheet of the present invention is preferably water repellent to a liquid having a surface tension of 60 mN/m (hereinafter also referred to as "low surface tension liquid"), more preferably water repellent to a liquid having a surface tension of 50 mN/m, and even more preferably water repellent to a liquid having a surface tension of 40 mN/m. By having such water repellency, the sheet of the present invention exhibits high leakproofness. In order for the sheet of the present invention to exhibit such water repellency, as described above, it is preferable that at least one surface of the sheet has an uneven structure. In addition, in order for the sheet of the present invention to exhibit such water repellency, it is advantageous for the sheet to have a nanofiber layer described later. In order to further increase the water repellency, a water repellent agent may be applied to the sheet of the present invention. Details of the water repellent agent will be described later.
It should be noted that surface tension depends on temperature, and the above surface tension values are those at 25°C.

Whether or not the sheet of the present invention has water repellency to a low surface tension liquid is judged by the following method.
As a low surface tension liquid, a "mixture for wetting tension test" available from Kanto Chemical Co., Ltd. is prepared.
A sheet of the present invention having an area capable of covering the entire area of a filter paper with a diameter of 7 cm is placed on the sheet of the present invention. A dry pulp sheet (basis weight 44 g/m ² ) cut to the same size as the sheet is placed on the sheet of the present invention. 1 g of low surface tension liquid is dropped on the center of the dry pulp sheet, and an acrylic resin plate with a diameter of 6 cm is placed at the dropping position. A weight is placed on the plate so that a pressure of 2 kPa is applied to the sheet of the present invention. After applying this pressure for 1 hour, the filter paper is removed and the area of the low surface tension liquid attached to the filter paper is measured. For example, the area can be measured by photographing the filter paper or scanning it with a scanner, and binarizing the image obtained by this with image analysis software. The area measured in this way is divided by the area of the filter paper, and if the area ratio (%) obtained by multiplying it by 100 is less than 5%, the sheet is judged to have water repellency. The area ratio is measured for 10 different sheets, and the arithmetic average value thereof is taken as the value of the area ratio.

In the sheet of the present invention, it is preferable that the width of the convex portions in the concave-convex structure formed on at least one surface is set to a specific range. The inventors have found that such a sheet has excellent ability to prevent liquid penetration.
The width of the convex portion of the concave-convex structure is defined according to the shape of the concave-convex structure. For example, as shown in Fig. 2 described later, when the convex portions are arranged in a scattered manner, the width of the convex portion means the linear distance between the most depressed portion located between the convex portions as the starting point and the end point (linear distance when the sheet is viewed in a plan view) when the start point passes through the top of the convex portion and the end point is the depressed portion located opposite to the start point in the plan view of the sheet.
On the other hand, for example, as shown in Figure 3 described later, when the convex portion is formed in the form of a stripe extending continuously along one direction, the width of the convex portion means the straight-line distance between the start point and the end point (the straight-line distance when the sheet is viewed in a plane) when the start point is the most recessed point in the thickness direction located between the convex portions in a direction perpendicular to the direction in which the convex portions extend, and the end point is a recessed point that passes through the top of the convex portion and is located opposite the start point when viewed in a plane of the sheet.

Regardless of the shape of the unevenness structure, it is preferable that the width of the convex portion is 0.5 mm or more in terms of ease of forming the unevenness structure, and from this viewpoint, it is more preferable that the width of the convex portion is 1 mm or more, and even more preferable that it is 1.5 mm or more.
On the other hand, the width of the convex portion is preferably 8 mm or less, since the convex portion is less likely to be crushed and the concave-convex structure can be stably maintained. From the viewpoint of making this advantage more prominent, the width of the convex portion is more preferably 6 mm or less, and even more preferably 4 mm or less.
Considering all of the above, the width of the convex portion is preferably 0.5 mm or more and 8 mm or less, more preferably 1 mm or more and 6 mm or less, and even more preferably 1.5 mm or more and 4 mm or less.

The width W of the protrusion is measured by the following method.
As shown in FIG. 1, the sheet is cut along its thickness direction so that the convex portions 11 and the concave portions 12 are arranged alternately, and the cut sheet is placed on a smooth table so that the convex portions 11 face upward. A flat plate is placed on the sheet, and a pressure of 49 Pa is applied. The shortest linear distance (length of a line segment parallel to the table) from the most recessed portion of the concave portion 12 to the most recessed portion of the adjacent concave portion 12, passing through the top of the convex portion, is measured by a microscope. When the concave portion 12 is an embossed portion (fused portion), the distance is the distance from the edge of the embossed portion closest to the convex portion 11 to the edge of the opposing embossed portion (the edge of the embossed portion closest to the convex portion). Five different cross sections are measured, and the distance is measured at three positions per cross section. The arithmetic average of a total of 15 measured values is calculated, and this value is the width W of the convex portion 11. The calculation is performed in millimeter order, and the value is rounded off to the nearest decimal place.

In the sheet of the present invention, the uneven structure is observed when no pressure is applied to the sheet. In addition, it is preferable from the viewpoint of improving leak resistance that the uneven structure be observed even when a pressure of 49 Pa is applied to the sheet of the present invention.

The sheet of the present invention can sufficiently prevent liquid penetration as long as it has an uneven structure on at least one surface. Therefore, the other surface may be a flat surface or may have an uneven structure.

The sheet of the present invention may have, for example, a configuration in which protrusions are arranged in a scattered manner on one surface of the sheet, and recesses are located between adjacent protrusions. Specifically, the sheet of the present invention may have, on one surface, protrusions and recesses arranged alternately along one direction, and protrusions and recesses arranged alternately along a direction perpendicular to the one direction. An example of a sheet of this configuration is shown in Figure 2. In the sheet 10 shown in the figure, the protrusions are indicated by the reference numeral 11, and the recesses are indicated by the reference numeral 12.

In the sheet 10 having the configuration shown in Fig. 2, the shape of the protrusions 11 in plan view may be, for example, a circle or an ellipse; a polygon such as a triangle, a rectangle, or a hexagon; or a combination thereof. The shapes of the protrusions 11 in plan view may all be the same or different.
On the other hand, in the sheet 10 having the configuration shown in FIG. 2, the shape of the recesses 12 in plan view may be, for example, a circle or an ellipse; a polygon such as a triangle, a rectangle, or a hexagon; a cross; or a combination thereof.

Another embodiment of the sheet of the present invention is one in which, on one surface of the sheet, protrusions that extend continuously in stripes along one direction within the surface and recesses that extend continuously in stripes along the one direction are alternately arranged in a direction perpendicular to the one direction. An example of a sheet of this type is shown in Figure 3. In the sheet 10 shown in the figure, the protrusions are indicated by the reference numeral 11 and the recesses are indicated by the reference numeral 12.

In either case of the sheet of the present invention having the embodiment shown in Fig. 2 or Fig. 3, the pitch of the convex portions is preferably 1 mm or more in terms of ease of forming a concave-convex structure. From the viewpoint of making this advantage more prominent, the pitch of the convex portions is more preferably 1.5 mm or more, and even more preferably 2 mm or more.
On the other hand, it is preferable that the pitch of the convex portions is 10 mm or less, because this allows a sufficient number of concaves and convexes to be provided per unit area, and the convex portions are less likely to be crushed, so that the concave-convex structure can be stably maintained. From the viewpoint of making this advantage more prominent, it is more preferable that the pitch of the convex portions is 9 mm or less, and even more preferable that it is 8 mm or less.
Considering all of the above, the pitch of the convex portions is preferably 1 mm or more and 10 mm or less, more preferably 1.5 mm or more and 9 mm or less, and even more preferably 2 mm or more and 8 mm or less.

Whether the sheet of the present invention is of the embodiment shown in FIG. 2 or FIG. 3, the pitch of the convex portions refers to the distance between the apexes of adjacent convex portions. If the pitch is not constant, the arithmetic average value is taken as the pitch of the convex portions.

The pitch P of the protrusions is measured by the following method.
As shown in FIG. 1, the sheet is cut along its thickness direction so that the convex portions 11 and the concave portions 12 are arranged alternately, and the cut sheet is placed on a smooth table so that the convex portions 11 face upward. A flat plate is placed on the sheet, and a pressure of 49 Pa is applied. The shortest linear distance (length of a line segment parallel to the table) from the highest point of the convex portion 11 to the highest point of the adjacent convex portion 11 across the concave portion 12 is measured using a microscope. Five different cross sections are measured, and the distance is measured at three positions per cross section. The arithmetic average of a total of 15 measured values is calculated, and this value is taken as the pitch P of the convex portions 11. The calculation is performed in millimeter order, and the first decimal place is rounded off.

2 and 3, the protrusions in the sheet may be solid or hollow. The protrusions being solid means that they are filled with fibers. The protrusions being hollow means that there is space inside the protrusions.
When the inside of the protrusions is hollow, the space inside the protrusions prevents liquid from passing through, which is advantageous in that the leakproofness of the sheet of the present invention is improved, whereas when the inside of the protrusions is solid, the sheet of the present invention is advantageous in that a cushioning feeling is imparted and the protrusions are unlikely to be crushed.

Regardless of whether the convex portions in the sheet of the present invention are solid or hollow, the height of the convex portions in the sheet is preferably 0.5 mm or more, more preferably 0.7 mm or more, and even more preferably 0.9 mm or more, from the viewpoint of imparting high leak-proofing properties to the sheet.
The height of the protrusions is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. By making the height of the protrusions lower than this value, it is possible to effectively prevent the protrusions from being excessively crushed by the pressure resistance of the wearer when the absorbent article is worn.
Considering all of the above, the height of the convex portion is preferably 0.5 mm or more and 5 mm or less, more preferably 0.7 mm or more and 4 mm or less, and even more preferably 0.9 mm or more and 3 mm or less.

The height H of the protrusion is measured by the following method.
As shown in FIG. 1, the sheet is cut along its thickness direction so that the convex portions 11 and the concave portions 12 are arranged alternately, and the cut sheet is placed on a smooth table so that the convex portions 11 face upward. A flat plate is placed on the sheet, and with a pressure of 49 Pa applied, an imaginary line is drawn parallel to the plate and the table, passing through the top of the concave portions 12. The distance between the imaginary line and the bottom surface of the plate is measured using a microscope. Five different cross sections are measured, and the distance is measured at three positions per cross section. The arithmetic average of a total of 15 measured values is calculated, and this value is the height H of the convex portions 11. The calculation is performed in millimeters and rounded off to the nearest tenth.

As described above, the sheet of the present invention has a structure in which multiple nonwoven fabric layers are laminated, and it is preferable that the multiple nonwoven fabric layers include at least a nanofiber layer. The nanofiber layer is a layer formed by depositing nanofibers. In this specification, nanofibers generally refer to fibers whose thickness is expressed as a circle equivalent diameter of 0.01 μm or more and 3 μm or less.

The nanofiber layer can be, for example, a meltblown layer. Also, the nanofiber layer can be, for example, an electrospun layer.
The meltblown layer is a layer of nonwoven fabric produced by the meltblown method, and more specifically, is a layer of nonwoven fabric produced by forming fibers by stretching a molten liquid of a raw material resin having fiber-forming ability with hot air, and then depositing the fibers on a collector.
The electrospinning layer is a layer of nonwoven fabric produced by the electrospinning method. More specifically, the electrospinning layer is a layer of nonwoven fabric produced by charging a solution or melt of a resin having fiber-forming ability and discharging it into an electric field, stretching the discharged liquid by the electric field to form fibers, and depositing the fibers on a collector.
Nanofibers having the above-mentioned thickness can be easily produced by either the meltblowing method or the electrospinning method.

The nanofiber layer preferably contains fibers with a fiber diameter of 1 μm or less. In particular, the inventors have found that a sheet made of a nonwoven fabric having a nanofiber layer with an uneven surface structure has an even better ability to block liquid penetration. The inventors believe that the reason for this is that liquid penetration is blocked by a synergistic effect between the nanofiber layer made of fine fibers and the uneven surface structure. However, the present invention is not bound by this theory.

From the viewpoint of further improving the leakproofness, the fiber diameter of the constituent fibers of the nanofiber layer is preferably 1 μm or less, more preferably 0.9 μm or less, as described above. There is no particular limit to the lower limit of the fiber diameter, and the smaller the fiber diameter, the higher the leakproofness of the sheet of the present invention, but sufficient leakproofness is achieved when the fibers are as thin as about 0.4 μm.
Considering the above points, the fiber diameter of the fibers constituting the nanofiber layer is preferably 0.4 μm or more and 1 μm or less, and more preferably 0.4 μm or more and 0.9 μm or less.
To produce a nanofiber layer made of fibers having a fiber diameter of 1 μm or less, for example, by a meltblown method, it is sufficient to appropriately adjust conditions during production, such as the temperature and discharge amount of the resin, the temperature, volume and speed of the hot air, the temperature of the spinning die, and the nozzle diameter, and the setting of these conditions is within the scope of common technical knowledge of a person skilled in the art.

The fiber diameter of the constituent fibers of the nanofiber layer is measured by the following method.
Five small samples are randomly taken from the nanofiber layer. Next, a scanning electron microscope is used to take a photograph at 1,000 to 10,000 times magnification so that 20 to 60 fibers of the nanofiber layer are captured in the field of view. The fiber diameters of 100 or more fibers are measured so that each fiber in the field of view is counted once, and the average value is calculated in micrometer order and rounded off to one decimal place. The value obtained in this manner is the fiber diameter of the fibers constituting the nanofiber layer.

When the sheet of the present invention has a nanofiber layer, from the viewpoint of further enhancing the leakproofness of the sheet, the nanofiber layer preferably has a basis weight of 1 g/m2 or ^more , more preferably 1.5 g/m2 or ^more , and even more preferably 2 g/ ^m2 or more. The greater the basis weight of the nanofiber layer, the higher the leakproofness, but from the viewpoints of the feel of the sheet and economy, the basis weight is preferably 10 g/ ^m2 or less, more preferably 9 g/m2 or ^less , and even more preferably 8 g/m2 or ^less .
Taking all of this into consideration, the nanofiber layer preferably has a basis weight of 1 g/m2 or ^{more and} 10 g/m2 ^or less, more preferably 1.5 g/m2 or ^more and 9 g/m2 or ^less , and even more preferably ² g/m2 or more and 8 g/m2 or ^less .

The basis weight of the nanofiber layer is measured by the following method.
A test piece measuring 10 cm x 10 cm is cut out from the sheet of the present invention using a razor. If a test piece of this size cannot be cut out, a test piece with as large an area as possible is cut out. The nanofiber layer is carefully removed from the test piece using hands or tweezers. The mass of the nanofiber is measured and divided by the area of the test piece to obtain the basis weight of the nanofiber layer.

In relation to the above-mentioned basis weight, from the viewpoint of further enhancing the leakproofness of the sheet of the present invention, the thickness of the nanofiber layer is preferably 3 μm or more and 150 μm or less, more preferably 10 μm or more and 120 μm or less, and even more preferably 15 μm or more and 100 μm or less.

The thickness of the nanofiber layer is measured by the following method.
The sheet of the present invention is cut in its thickness direction with a razor or the like so that convex portions and concave portions are arranged alternately, and a photograph is taken with a scanning electron microscope at a magnification of 150 to 1000 times so that the nanofiber layer is in the center of the field of view and the layers adjacent to the nanofiber layer above and below it.
A boundary line is drawn between the nanofiber layer and adjacent layers based on the difference in fiber diameter.
The shortest straight line distance between two boundaries sandwiching the nanofiber layer is measured.
This operation is performed on 10 different cross sections, and the arithmetic mean value of the measured values is calculated for one point per cross section, for a total of 10 points. The mean value is calculated in the order of micrometers and rounded off to the nearest integer.

The fibers constituting the nanofiber layer are preferably made of a thermoplastic resin having fiber-forming ability. The fibers constituting the nanofiber layer are preferably made of, for example, polyolefins such as polypropylene, polyethylene, and ethylene-α-olefin copolymers, and polyesters such as polyethylene terephthalate. From the viewpoint of easily producing a nanofiber layer with a fine fiber diameter, it is preferable to use polypropylene.

The sheet of the present invention preferably includes another nonwoven fabric layer in addition to the nanofiber layer. The other nonwoven fabric layer is used for the purpose of, for example, imparting a good feel to the sheet of the present invention, imparting an uneven structure to the surface of the sheet of the present invention, or supporting the nanofiber layer. Examples of the other nonwoven fabric layer include layers manufactured by various nonwoven fabric manufacturing methods, such as a spunbond layer, an air-through layer, an airlaid layer, a spunlace layer, and a needle punch layer. In addition, it is also preferable that the other nonwoven fabric layer has elasticity, since this can improve the ability to follow the wearer's movements when wearing an absorbent article including the sheet of the present invention.

When the sheet of the present invention has a nanofiber layer, it is preferable that the nanofiber layer in the sheet is a meltblown layer, and that the meltblown layer has a spunbond layer disposed on at least one side thereof. As described above, the meltblown layer is composed of fine fibers, and therefore tends to have low strength. Therefore, by disposing a spunbond layer adjacent to the meltblown layer on at least one side of the meltblown layer, the strength of the meltblown layer is maintained. From this viewpoint, it is further preferable that the meltblown layer has a spunbond layer disposed adjacent to the meltblown layer on both sides thereof.

In the following description, a laminate structure consisting of a nanofiber layer such as a meltblown layer or an electrospun layer and a pair of spunbond layers arranged adjacent to the nanofiber layer on both sides of the nanofiber layer is also referred to as an "SNS layer."

When the sheet of the present invention has an SNS layer, the spunbond layers in the SNS layer may be the same or different in basis weight and/or thickness, and the resin type of the constituent fibers of the spunbond layers in the SNS layer may be the same or different.
Each spunbond layer in the SNS layer preferably has a basis weight of 3 g/m2 or ^more and 50 g/ ^m2 or less, more preferably 4 g/m2 ^{or more} and 40 g/m2 ^{or less} , and even more preferably 5 g/m2 or ^more and 30 g/m2 or ^less .
Each spunbond layer in the SNS layer preferably has a thickness of 50 μm to 500 μm, more preferably 60 μm to 400 μm, and even more preferably 70 μm to 300 μm. The thickness of the spunbond layer is measured in the same manner as the method for measuring the thickness of the nanofiber layer described above.
It is preferred that the resin of the constituent fibers of each spunbond layer in the SNS layer is independently composed of, for example, polyolefin such as polypropylene, polyethylene, ethylene-α-olefin copolymer, or polyester such as polyethylene terephthalate.

When the sheet of the present invention has an SNS layer, the SNS layer may (a) constitute the uneven structure of the sheet of the present invention, (b) be present in a portion other than the uneven structure, or (c) be present in both the uneven structure and in a portion other than the uneven structure.
In the case of (a), there is an advantage that the SNS layer itself is not easily pulled even if the sheet itself is pulled. Therefore, even if the wearer moves while wearing the absorbent article including the sheet of the present invention, the leakproofness of the SNS layer is likely to be maintained.
In the case of (b), there is an advantage that the sheet can be easily produced without destroying the fiber structure of the SNS layer.
In the case of (c), even if the fiber structure of the SNS layer that constitutes the uneven structure is destroyed during the production of the sheet, the SNS layer existing in areas other than the uneven structure can ensure leakproofness.

4(a) shows a schematic cross-sectional structure in the thickness direction of the sheet of the present invention. The sheet 10 shown in the figure has a first surface 21 and a second surface 22 located on the opposite side. The first surface 21 side of the sheet 10 has an uneven structure. On the other hand, the second surface 22 is a flat surface.
A single spunbond layer 13 is located on the first surface 21 side of the sheet 10. The spunbond layer 13 forms protrusions 11 and recesses 12. The interior of the protrusions 11 is hollow.
On the second surface 22 side of the sheet 10, there is positioned a SNS layer 15 composed of a spunbond layer 13, a nanofiber layer 14 and a spunbond layer 13. Each surface of the SNS layer 15 is flat.
The spunbond layer 13 located on the first surface 21 side is bonded at its recess 12 to the spunbond layer 13 in the SNS layer 15 located on the second surface 22 side. This bonding forms a bonded portion 16. The shape of the bonded portion 16 in a plan view can be various shapes depending on the shape of the protruding portion 11 in a plan view. When the protruding portion 11 has a shape shown in FIG. 2, for example, the bonded portion 16 can be arranged in a scattered dot pattern, for example, a circle, an ellipse, a polygon, a cross, or the like. When the protruding portion 11 has a shape shown in FIG. 3, for example, the bonded portion 16 can be linear, curved, dashed, or the like.
The joint 16 is formed by various joining means such as fusion or adhesion.
The sheet 10 of the embodiment shown in FIG. 4(a) has the protrusions 11 and the nanofiber layer 14, and therefore exhibits high leak-proofing properties.

4(b), a SNS layer 15 consisting of a spunbond layer 13, a nanofiber layer 14 and a spunbond layer 13 is located on the first surface 21 side. The SNS layer 15 constitutes the protrusions 11 and the recesses 12. The interior of the protrusions 11 is hollow.
A single spunbond layer 13 is located on the second surface 22 of the sheet 10. The spunbond layer 13 has flat surfaces on both sides.
The SNS layer 15 is bonded at the recess 12 to the spunbond layer 13 located on the second surface 22 side. A bonded portion 16 is formed by this bonding.
The rest of the configuration is the same as that of the embodiment shown in FIG.
The sheet 10 of the embodiment shown in FIG. 4(b) has protrusions 11 and a meltblown layer 14 is located at the protrusions 11, and therefore exhibits even higher leak prevention properties than the embodiment shown in FIG. 4(a).

4(c) has a first SNS layer 15a, which is composed of a spunbond layer 13, a nanofiber layer 14 and another spunbond layer 13, located on the first surface 21 side of the sheet 10. The first SNS layer 15a constitutes the protrusions 11 and the recesses 12. The interior of the protrusions 11 is hollow.
A second SNS layer 15b is located on the second surface 22 side of the sheet 10. The second SNS layer 15b also comprises a spunbond layer 13, a nanofiber layer 14 and another spunbond layer 13. Each surface of the second SNS layer 15b is flat.
The rest of the configuration is similar to that of the embodiment shown in FIG.
According to the embodiment of the sheet 10 shown in FIG. 4(c), in addition to the nanofiber layer 14 being located on the convex portion 11, the nanofiber layer 14 is also located on the second surface 22 side, so that the leak-proofing is further improved compared to the embodiment shown in FIG. 4(b).

The sheet of the present invention preferably has an air-through layer. The air-through layer is used for the purpose of imparting a good feel to the sheet of the present invention. When the sheet of the present invention is manufactured by the method shown in FIG. 11 described later, the air-through layer is used for the purpose of imparting an uneven shape to the surface of the sheet of the present invention.

When the sheet of the present invention includes an air-through layer, the air-through layer can be disposed adjacent to the nanofiber layer. For example, an air-through layer can be disposed adjacent to one side of the nanofiber layer. Alternatively, an air-through layer can be disposed adjacent to each side of the nanofiber layer.

When an air-through layer is disposed on each side of the nanofiber layer, the air-through layers may be the same or different in basis weight and/or thickness, and the type of resin of the constituent fibers of the air-through layers may be the same or different.
The basis weight of each air-through layer is preferably 6 g/m2 or ^more and 70 g/m2 ^or less, more preferably 8 g/m2 ^{or more} and 60 g/m2 ^{or less} , and even more preferably 10 g/m2 ^or more and 50 g/m2 or ^less .
Each air-through layer preferably has a thickness of 0.3 mm or more and 5 mm or less, more preferably 0.4 mm or more and 4 mm or less, and even more preferably 0.5 mm or more and 3 mm or less. The thickness of the air-through layer is measured by the same method as the method for measuring the thickness of the nanofiber layer described above.
The resin of the constituent fibers of each air-through layer is preferably composed of, for example, polyolefin such as polypropylene, polyethylene, ethylene-α-olefin copolymer, or polyester such as polyethylene terephthalate. The type of resin of the constituent fibers of each air-through layer may be the same or different. Furthermore, each air-through layer may be composed of core-sheath type composite fibers or side-by-side type composite fibers containing these resins.

Fig. 5 shows a schematic cross-sectional structure in the thickness direction of the sheet of the present invention. The sheet 10 shown in the figure has a first surface 21 and a second surface 22 located on the opposite side. The first surface 21 side of the sheet 10 has an uneven structure. On the other hand, the second surface 22 is a flat surface.
5 has a structure in which air-through layers 17a, 17b are disposed on each side of a nanofiber layer 14. The nanofiber layer 14 and the pair of air-through layers 17a, 17b each protrude toward the first surface 21 to form a protrusion 11. The inside of the protrusion 11 is solid. The inside of the protrusion 11 is filled mainly with the constituent fibers of the air-through layer 17b located on the second surface 22 side.
Of the pair of air through layers 17a, 17b, the air through layer 17b located on the second surface 22 side has a flat outer surface (i.e., exposed surface).
The nanofiber layer 14 and the pair of air-through layers 17 a, 17 b are consolidated and integrally bonded in the recesses 12 of the sheet 10 .
The rest of the configuration is the same as that of the embodiment shown in FIG.
The sheet 10 of the embodiment shown in FIG. 5 has the protrusions 11 and the nanofiber layer 14 is located on the protrusions 11, and therefore exhibits high leakproofness.

When the sheet of the present invention has an SNS layer, it is also preferable that an air-through layer is disposed on the outer surface of at least one of the pair of spunbond layers in the SNS layer (i.e., the surface opposite to the surface facing the nanofiber layer). In other words, it is preferable that the sheet of the present invention has an SNS layer and an air-through layer disposed adjacent to the outer surface of at least one spunbond layer in the SNS layer. In the following description, the laminated structure of the SNS layer and the air-through layer disposed adjacent to the outer surface of at least one spunbond layer in the SNS layer is also referred to as the "SNS+AT layer."

When the sheet of the present invention has a [SNS+AT] layer, the air-through layer in the [SNS+AT] layer may (a) constitute the uneven structure of the sheet of the present invention, or (b) be present in a portion other than the uneven structure.
In the case of (a), when the uneven surface is the skin-facing surface, the uneven structure has the advantage of reducing the contact area with the absorbent and suppressing adhesion of body fluids to the SNS layer. On the other hand, when the uneven surface is the non-skin-facing surface, the sheet has the advantage of being able to have a designable appearance. In this case, the suitable basis weight of the air-through layer is as described above.
In the case of (b), when the air-through layer is located on the skin-facing side, there is an advantage that the contact area between the absorbent and the SNS layer can be reduced. When the air-through layer is located on the non-skin-facing side, there is an advantage that the feel against the skin can be improved. The suitable basis weight of the air-through layer in this case is as described above.

6(a) shows a schematic cross-sectional structure in the thickness direction of a sheet of the present invention having an [SNS+AT] layer. The sheet 10 shown in the figure has a first surface 21 and a second surface 22 located on the opposite side. The first surface 21 side of the sheet 10 has an uneven structure. On the other hand, the second surface is a flat surface.
6(a), the air through layer 17 is located on the first surface 21 side. The air through layer 17 constitutes the protrusions 11 and the recesses 12. The inside of the protrusions 11 is solid.
The SNS layer 15 is located on the second surface 22 side of the sheet 10. The SNS layer 15 has each flat surface.
The air-through layer 17 is consolidated and integrally joined to the SNS layer 15 located on the second surface 22 side at the recess 12. A joint 16 is formed by this joining.
The rest of the configuration is the same as that of the embodiment shown in FIG.
The sheet 10 shown in FIG. 6(a) has protrusions 11 and a nanofiber layer 14, and therefore exhibits high leak-proofing properties.

In the sheet 10 shown in Fig. 6(b), the inside of the protrusion 11 formed by the air-through layer 17 is hollow. The rest of the configuration is the same as that of the embodiment shown in Fig. 6(a).
In the sheet 10 shown in FIG. 6(b), the insides of the protrusions 11 are hollow, and therefore the sheet 10 has a higher liquid permeability barrier than the sheet shown in FIG. 6(a).

7(a) shows a schematic cross-sectional structure in the thickness direction of a sheet having an [SNS+AT] layer according to another embodiment of the present invention. The sheet 10 shown in the figure has a first surface 21 and a second surface 22 located on the opposite side. The first surface 21 side of the sheet 10 has an uneven structure. On the other hand, the second surface is a flat surface.
7A, the SNS layer 15 is located on the first surface 21 side. The SNS layer 15 constitutes the protrusions 11 and the recesses 12.
The air-through layer 17 is located on the second surface 22 side of the sheet 10. The outer surface (i.e., the exposed surface) of the air-through layer 17 is flat. The surface of the air-through layer 17 facing the SNS layer 15 has an uneven structure. This uneven structure has a complementary shape to the uneven structure formed by the SNS layer 15. Therefore, the inside of the protrusions 11 is solid, and is filled with the constituent fibers of the air-through layer 17.
The SNS layer 15 is consolidated and integrally joined at the recess 12 to the air-through layer 17 located on the second surface 22 side. A joint 16 is formed by this joining.
The rest of the configuration is the same as that of the embodiment shown in FIG.
The sheet 10 shown in FIG. 7(a) has protrusions 11 and a nanofiber layer 14, and therefore exhibits high leak-proofing properties.

In the sheet 10 shown in Fig. 7(b), the constituent fibers of the air-through layer 17 are present inside the protrusions 11. However, the constituent fibers of the air-through layer 17 do not completely fill the inside of the protrusions 11, and spaces exist inside the protrusions 11, making the insides of the protrusions hollow. The rest of the configuration is the same as in the embodiment shown in Fig. 7(a).
In the sheet 10 shown in FIG. 7(b), the insides of the protrusions 11 are hollow, and therefore the sheet 10 has a higher liquid permeability barrier than the sheet shown in FIG. 7(a).

8 is a schematic diagram showing a cross-sectional structure in the thickness direction of a sheet having an [SNS+AT] layer according to another embodiment of the present invention. The sheet 10 shown in the figure has a first surface 21 and a second surface 22 located on the opposite side. The first surface 21 of the sheet 10 has an uneven structure. On the other hand, the second surface 22 is a flat surface.
The sheet 10 shown in Fig. 8 has a structure in which air-through layers 17a, 17b are arranged on each side of the SNS layer 15. The SNS layer 15 and the pair of air-through layers 17a, 17b each protrude toward the first surface 21 to form a convex portion 11. The inside of the convex portion 11 is solid. The inside of the convex portion 11 is filled mainly with the constituent fibers of the air-through layer 17b located on the second surface 22 side.
Of the pair of air through layers 17a, 17b, the air through layer 17b located on the second surface 22 side has a flat outer surface (i.e., exposed surface).
The SNS layer 15 and the pair of air-through layers 17a, 17b are consolidated and integrally joined in the recesses 12 of the sheet 10.
The rest of the configuration is the same as that of the embodiment shown in FIG.
The sheet 10 of the embodiment shown in FIG. 8 has the protrusions 11 and the nanofiber layer 14 is located on the protrusions 11, and therefore exhibits high leakproofness.

9(a) shows a schematic cross-sectional structure in the thickness direction of a sheet having an [SNS+AT] layer according to another embodiment of the present invention. The sheet 10 shown in the figure has a first surface 21 and a second surface 22 located on the opposite side. The first surface 21 side of the sheet 10 has an uneven structure. On the other hand, the second surface is a flat surface.
9(a), a first SNS layer 15a consisting of a spunbond layer 13, a nanofiber layer 14 and another spunbond layer 13 is located on the first surface 21 side of the sheet 10. The first SNS layer 15a constitutes the protrusions 11 and the recesses 12.
A second SNS layer 15b is located on the second surface 22 side of the sheet 10. The second SNS layer 15b also comprises a spunbond layer 13, a nanofiber layer 14 and another spunbond layer 13. Each surface of the second SNS layer 15b is flat.
An air-through layer 17 is disposed between the first SNS layer 15a and the second SNS layer 15b. The air-through layer 17 is located within the protrusions 11 so as to fill the entire space of the protrusions 11 defined by the first SNS layer 15a and the second SNS layer 15b. Therefore, the inside of the protrusions 11 is solid and is filled with the constituent fibers of the air-through layer 17.
According to the embodiment of the sheet 10 shown in FIG. 9( a ), in addition to the nanofiber layer 14 being located on the convex portion 11, the nanofiber layer 14 is also located on the second surface 22 side, thereby further improving the leakproofness.

In the sheet 10 shown in Fig. 9(b), the constituent fibers of the air-through layer 17 are present inside the protrusions 11 defined by the first SNS layer 15a and the second SNS layer 15b. However, the constituent fibers of the air-through layer 17 do not completely fill the inside of the protrusions 11, and spaces exist inside the protrusions 11, making the inside of the protrusions hollow. The rest of the configuration is the same as that of the embodiment shown in Fig. 9(a).
In the sheet 10 shown in FIG. 9(b), the insides of the protrusions 11 are hollow, and therefore the sheet 10 has a higher liquid permeability barrier than the sheet shown in FIG. 9(a).

Figure 10 shows yet another embodiment of the sheet 10 of the present invention. The sheet 10 shown in the figure has a first surface 21 and a second surface 22 located on the opposite side. The first surface 21 side of the sheet 10 has an uneven structure. On the other hand, the second surface 22 is a flat surface. The sheet 10 has a first nonwoven fabric layer 23 with an uneven structure located on the first surface 21 side. The second nonwoven fabric layer 24 is located on the second surface 22 side. The two nonwoven fabric layers 23, 24 are joined at a joint 16.

The first nonwoven fabric layer 23 of the sheet 10 constitutes the protrusions 11 and the recesses 12. The inside of the protrusions 11 is hollow.
The first nonwoven fabric layer 23 is made of a nanofiber layer or a nonwoven fabric layer containing a nanofiber layer.
When the first nonwoven fabric layer 23 is made of a nanofiber layer, the nanofiber layer is preferably a meltblown layer or an electrospun layer.
On the other hand, when the first nonwoven fabric layer 23 is made of a nonwoven fabric layer containing a nanofiber layer, the first nonwoven fabric layer 23 is preferably a laminated nonwoven fabric in which a spunbonded nonwoven fabric or an air-through nonwoven fabric is laminated on one or both sides of the nanofiber layer. The nanofiber layer is preferably a meltblown layer or an electrospun layer.

The second nonwoven fabric layer 24 located on the second surface 22 side of the sheet 10 shown in FIG. 10 has flat surfaces.
The second nonwoven fabric layer 24 is preferably a nonwoven fabric containing elastic filaments, and a particularly preferred nonwoven fabric is a nonwoven fabric containing elastic filaments and inelastic fibers.
In the second nonwoven fabric layer 24, the elastic filaments 25 are preferably bonded in a substantially unstretched state to nonwoven fabrics 26, 26 containing inelastic fibers. Also, the second nonwoven fabric layer 24 preferably has a configuration in which a plurality of elastic filaments 25 are bonded to two nonwoven fabrics 26, 26.
The elastic filaments 25 are preferably arranged to extend in one direction X without crossing each other, thereby enabling the elastic filaments 25 to be stretched in the one direction X. As long as the elastic filaments 25 do not cross each other, they may extend linearly or may extend in a meandering manner.
Moreover, the elastic filaments 25 are preferably arranged at intervals in a direction perpendicular to the X direction (i.e., perpendicular to the paper surface).

It is preferable that each of the nonwoven fabrics 26, 26 constituting the second nonwoven fabric layer 24 is extensible. The nonwoven fabrics 26, 26 typically contain substantially inelastic fibers and are substantially inelastic.
The "elasticity" of the elastic filaments 25 and the non-elastic "elasticity" of the nonwoven fabric 26 refer to the property of being able to be stretched and returning to a length of 110% or less of the original length when the force is released from a state stretched 50% of the original length (a state in which the length is 150% of the original length, i.e., 1.5 times the original length).
It is preferable that the nonwoven fabrics 26, 26 are stretchable in the same direction as the X direction in which the elastic filaments 25 extend.
In this specification, "stretchable" includes (i) the case where the constituent fibers of the nonwoven fabrics 26, 26 themselves stretch, and (ii) the case where the constituent fibers themselves do not stretch, but the nonwoven fabric as a whole stretches as a result of fibers that were bonded at intersections becoming separated, the three-dimensional structure formed by multiple fibers due to bonding between fibers, etc., changing structurally, constituent fibers breaking, or slack fibers being stretched.
Each of the nonwoven fabrics 26, 26 may already be extensible in the state of a raw roll before being joined to the elastic filament 25. Alternatively, the nonwoven fabrics 26, 26 may not be extensible in the state of a raw roll before being joined to the elastic filament 25, but may be processed so as to become extensible after being joined to the elastic filament 25. Specific methods for making the nonwoven fabric 26 extensible include heat treatment, stretching between rolls, biting stretching by teeth or gears, and tensile stretching by a tenter. In view of a suitable manufacturing method for the sheet 10 described later, it is preferable that the nonwoven fabric 26 is not extensible in the state of its raw roll, in order to improve the transportability of the nonwoven fabric 26 when the elastic filament 25 is fused to the nonwoven fabric 26.

The multiple elastic filaments 25 constituting the second nonwoven fabric layer 24 are preferably each substantially continuous over the entire length of the second nonwoven fabric layer 24. Each elastic filament 25 typically contains an elastic resin.

The elastic filaments 25 may be synthetic or natural rubber in the form of threads. Alternatively, they may be obtained by dry spinning (melt spinning) or wet spinning. The elastic filaments 25 are preferably obtained by direct melt spinning without being wound up. Also, the elastic filaments 25 are preferably obtained by drawing undrawn threads.
In addition, the elastic filaments 25 are preferably formed by stretching the elastic resin in a molten or softened state, which makes it easier to bond the elastic filaments 25 to the nonwoven fabric 26 in a non-stretched state.
Specific examples of the stretching operation include (a) melt-spinning the resin that is the raw material of the elastic filaments 25 to obtain an unstretched yarn, and then reheating the elastic filaments of the unstretched yarn to stretch them at a temperature equal to or higher than the softening temperature (glass transition temperature Tg of the hard segment), and (b) directly stretching the molten fibers obtained by melt-spinning the resin that is the raw material of the elastic filaments 25. In a suitable method for producing the sheet 10 described below, the elastic filaments 25 are obtained by directly stretching the molten fibers obtained by melt-spinning.

Each elastic filament 25 is preferably bonded to the nonwoven fabrics 26, 26 along its entire length.
"Bonded throughout its entire length" does not require that all fibers (constituent fibers of nonwoven fabric 26) in contact with elastic filament 25 are bonded to said elastic filament 25, but means that elastic filament 25 and constituent fibers of nonwoven fabric 26 are bonded in such a manner that there are no intentionally formed unbonded portions in elastic filament 25.
The elastic filament 25 and the nonwoven fabrics 26, 26 may be joined by, for example, welding or bonding with an adhesive. It is also preferable to weld the elastic filament 25 to the nonwoven fabric 26 before solidification of the elastic filament 25 obtained by melt spinning. In this case, before joining the nonwoven fabric 26 and the elastic filament 25, an adhesive can be applied as an auxiliary joining means. Alternatively, after joining each nonwoven fabric 26 and the elastic filament 25, a heat treatment (steam jet, heat embossing) or mechanical entanglement (needle punch, spun lace) can be performed as an auxiliary joining means.
The bonding between the nonwoven fabric 26 and the elastic filaments 25 is preferably achieved simply by the elastic filaments 25 in a molten or softened state solidifying when in contact with the nonwoven fabric 26, i.e., without using any adhesive, in order to improve the flexibility of the second nonwoven fabric layer 24.

The stretchability of the second nonwoven fabric layer 24 is due to the elasticity of the elastic filaments 25. When the second nonwoven fabric layer 24 is stretched in the same direction as the elastic filaments 25 extend, the elastic filaments 25 and the nonwoven fabrics 26, 26 are stretched. When the stretching of the second nonwoven fabric layer 24 is released, the elastic filaments 25 contract, and as a result of this contraction, the nonwoven fabric 26 returns to its state before it was stretched.

As the second nonwoven fabric layer 24, it is preferable to use a non-stretchable composite material produced by joining elastic filaments 25 in a non-stretched state to non-stretchable nonwoven fabrics 26, 26, and then passing this composite material as a raw sheet between a pair of interlocking uneven surfaces having alternating ridges and grooves, specifically, between a pair of rolls having toothed grooves, to exhibit elasticity. Details of this manufacturing method will be described later.

In the sheet of the present invention, it is preferable that a part or all of the nanofiber layer is located on one side of the half of the thickness direction. This further enhances the leakproofness of the sheet of the present invention. In particular, in a state in which the sheet of the present invention is incorporated into an absorbent article as a constituent member of the absorbent article, it is preferable that a part or all of the nanofiber layer is located closer to the absorbent body than the half of the thickness direction of the sheet, and in particular that the entire nanofiber layer is located, in order to further enhance the leakproofness. From this viewpoint, for example, in the embodiments shown in Figures 4(b), 4(c), 5, 7(a), 7(b), 8, 9(a), 9(b), and 10, it is preferable to arrange the sheet 10 so that the first surface 21 faces the absorbent body, and in the embodiments shown in Figures 4(a), 6(a), and 6(b), it is preferable to arrange the sheet 10 so that the second surface 22 faces the absorbent body.
The above-mentioned "half of the thickness direction" refers to half of the thickness measured in a state where a pressure of 49 Pa is applied to the sheet of the present invention.

Regardless of which embodiment of the sheet of the present invention is shown in Figures 4 to 10, when the sheet of the present invention is used as a component of an absorbent article, it is preferable to arrange the surface of the sheet having the uneven structure so that it faces the absorbent body. For example, the sheet of the present invention can be arranged on the non-skin-facing surface of the absorbent body and arranged so that the surface of the sheet having the uneven structure faces the absorbent body, and used as a back sheet. The sheet of the present invention can also be used as a leak-proof cuff, with the surface of the sheet having the uneven structure being the inner surface (i.e., the surface facing the absorbent body). By arranging the sheet of the present invention in this way, it is possible to further improve the leak-proofness of the sheet.

When the surface of the sheet of the present invention having the uneven structure is arranged to face the absorbent body, the sheet preferably has a nonwoven fabric layer flatter than the skin-facing surface on the non-skin-facing side of the nanofiber layer. This makes it easier to maintain the uneven structure. Therefore, even if the wearer moves while wearing the absorbent article including the sheet of the present invention, the effect of being able to stably reduce the contact area between the sheet of the present invention and the absorbent body is achieved. The nonwoven fabric layer flatter than the skin-facing surface is preferably a layer other than the nanofiber layer, but may be a nanofiber layer or a layer including a nanofiber layer. From this viewpoint, for example, in the embodiments shown in Figures 4(b), 4(c), 5, 7(a), 7(b), 8, 9(a), 9(b), and 10, it is preferable to arrange the sheet 10 so that the first surface 21 faces the absorbent body.

When the surface of the sheet of the present invention having the uneven structure is disposed so as to face an absorbent body, the sheet also preferably has an air-through layer on the non-skin facing side of the nanofiber layer, which enhances the cushioning effect of the air-through layer and improves the feel of the absorbent article against the skin.
For example, in the embodiments shown in Figures 5, 7(a), 7(b), 8, 9(a), 9(b) and 10, it is preferable to use the first surface 21 as the skin-facing surface and the second surface 22 as the non-skin-facing surface.

When the surface of the sheet of the present invention having the uneven structure is disposed so as to face an absorbent body, the sheet also preferably has an air-through layer on the skin-facing side of the nanofiber layer, which enhances the cushioning effect of the air-through layer and improves the feel of the absorbent article against the skin.
For example, in the embodiment shown in FIG. 5, it is preferable to use the first surface 21 as the skin-facing surface and the second surface 22 as the non-skin-facing surface.

Regardless of which embodiment of the sheet of the present invention is shown in Figs. 4 to 10, the sheet of the present invention may or may not have elasticity. If the sheet of the present invention has elasticity, there is an advantage that the sheet can better follow the wearer's movements when wearing an absorbent article including the sheet of the present invention. In this specification, elasticity refers to the property of being stretchable in a specific direction and shrinking when the stretch is released.

Next, a preferred method for manufacturing the sheet of the present invention will be described. FIG. 11 shows a schematic diagram of an example of a preferred apparatus used to manufacture the sheet of the present invention. The apparatus 40 shown in the figure is suitable for use in manufacturing the sheet 10 shown in, for example, FIGS. 7(a), 7(b) and 8.

The device 30 shown in FIG. 11 includes a carding machine 31. In the carding machine 31, a carded web 32 is produced. The carded web 32 preferably contains heat-shrinkable fibers that can shrink when heat is applied. It is preferable to use latent crimp fibers as the heat-shrinkable fibers, since this allows the production of a sheet with clear protrusions.

The card web 32 unwound from the carding machine 31 is overlapped with the SNS web 33 during the transport process. The SNS web 33 is a three-layer laminated web in which a spunbond layer is disposed on each side of a meltblown layer. In the SNS web 33, the three layers may be bonded and integrated by various bonding means such as heat embossing or adhesives. Alternatively, the three layers may be laminated without being bonded. Note that instead of the SNS web 33, a meltblown web or a two-layer laminated web in which a spunbond layer is disposed on one side of a meltblown layer may be used.

The card web 32 and the SNS web 33 are introduced into a thermal embossing roll device 34 equipped with an embossing roll 34a and an anvil roll 34b, where they are thermally embossed. The thermal embossing process partially bonds and integrates the two webs 32, 33. This results in a precursor 35 of the desired sheet.

The obtained sheet precursor 35 is introduced into a heat treatment device 36 arranged on the transport path thereof and subjected to a heat treatment. The heat treatment is performed at a temperature equal to or higher than the heat shrinkage initiation temperature of the heat-shrinkable fiber contained in the card web 32.
The heat treatment causes the heat-shrinkable fibers in the carded web 32 to shrink, and the dimension of the carded web 32 in the surface direction is shortened. On the other hand, since the SNS web 33 does not contain heat-shrinkable fibers, the SNS web 33 does not shrink due to heat. Even if the dimension of the carded web 32 in the surface direction is shortened, the dimension of the SNS web 33 in the surface direction does not change, so the fibers constituting the SNS web 33 have nowhere to go and move in the thickness direction. As a result, the SNS web 33 bulges. The SNS web 33 bulges between the joints between the carded web 32 and the SNS web 33. This causes a large number of protrusions to be formed on the SNS web 33. The joints become recesses located between the protrusions. In this way, the desired sheet 10 is obtained.
The heat treatment in the heat treatment device 36 may be performed by blowing hot air using an air-through method, or may be performed by irradiating microwaves, blowing steam, irradiating infrared rays, or contacting with a heat roll.
During the heat treatment, it is preferable to fix the sheet precursor 35 with a pin tenter from the viewpoint of forming clear protrusions 11 .

By appropriately controlling the heat treatment conditions in the heat treatment device 36 to increase the degree of shrinkage of the card web 32, a sheet 10 is obtained in which the inside of the protrusions 11 is filled with fibers, as shown in FIG. 7(a). On the other hand, when the degree of shrinkage of the card web 42 is small, a sheet 10 is obtained in which the inside of the protrusions 11 has spaces, as shown in FIG. 7(b).

Figure 12 shows a schematic diagram of an example of an apparatus suitable for use in producing the sheet of the present invention. The apparatus 40 shown in the figure is suitable for use in producing the sheets 10 shown in, for example, Figures 4(a), 4(b), 4(c), 6(b), and 7(b).

12, the manufacturing of the sheet 10 involves a step of overlapping the second fiber sheet 42 on one side of the first fiber sheet 41 having been shaped to have projections and recesses, and a step of bonding the first fiber sheet 41 and the second fiber sheet 42. Before the bonding step, a step of forming the first fiber sheet 41 to have projections and recesses is performed.
The first fiber sheet 41 is a raw sheet of a nonwoven fabric layer located on the first surface 21 side of the sheet 10, and in the sheet 10 shown in FIG. 4(a), for example, it is a raw sheet of a spunbond layer 13 having a concavo-convex structure.
The second fiber sheet 42 is a raw sheet of a nonwoven fabric layer located on the second surface 22 side of the sheet 10, and is, for example, a raw sheet of the SNS layer 15 in the sheet 10 shown in FIG.

The manufacture of the sheet 10 using the device 40 shown in Fig. 12 will be described in detail. First, the uneven shaping of the first fiber sheet 41 will be described. The uneven shaping of the first fiber sheet 41 is preferably performed by a shaping device 45 including a first roll 43 having an uneven peripheral surface and a second roll 44 having an uneven peripheral surface that meshes with the uneven surface of the first roll 43.
It is preferable that each of the first roll 43 and the second roll 44 has a structure in which convex streak portions 46A and concave streak portions 46B extending along the rotation axis of the roll are alternately arranged along the rotation direction of the roll.
The first roll 43 and the second roll 44 are configured to rotate in opposite directions with the peripheral surfaces of the two rolls meshing with each other.

With both rolls 43, 44 engaged, the first fiber sheet 41 is fed to the meshing portion of the rolls 43, 44 to give the first fiber sheet 41 an uneven shape. At the meshing portion of the rolls 43, 44, multiple locations of the first fiber sheet 41 are pressed into the grooves of the first roll 43 by the convex portions of the second roll 44, and the pressed-in portions become the convex portions 11 of the desired sheet 10.

When forming the unevenness, it is preferable to suck air from the outside of the peripheral surface of the first roll 43 toward the inside of the roll 43 to adhere the first fiber sheet 41 to the peripheral surface, in order to ensure that the first fiber sheet 41 is formed with unevenness. For this purpose, it is preferable to provide suction holes (not shown) in the grooves provided in the first roll 43, and to suck air from the outside of the roll 43 toward the inside through the suction holes.

It is preferable that the first fiber sheet 41 having the irregular shape is conveyed while being held on the peripheral surface of the first roll 43, and moves from the meshing portion.
Meanwhile, the second fiber sheet 42 is unwound from its original roll and overlapped with the unevenly shaped first fiber sheet 41. Simultaneously with or after overlapping of the two sheets 41, 42, the two sheets 41, 42 are introduced into a joining device 47. The joining device 47 may be, for example, a heat roll as shown in the figure. Alternatively, the joining device 47 may be an ultrasonic sealing device (not shown) equipped with an ultrasonic horn.
In the joining device 47 , the first fiber sheet 41 and the second fiber sheet 42 are partially joined together to form the above-mentioned joined portion 16 .

When manufacturing the sheet 10 using the device 40 shown in FIG. 12, it is preferable to set the supply speed V1 of the first fiber sheet 41 faster than the supply speed V2 of the second fiber sheet 42. This makes the first fiber sheet 41 less susceptible to damage when the unevenness is formed on the first fiber sheet 41. This is particularly effective when the first fiber sheet 41 contains a meltblown layer. This is because the meltblown layer has a relatively low strength and is easily damaged by the unevenness. The supply speed V1 of the first fiber sheet 41 should be faster than the supply speed V2 of the second fiber sheet 42 to the extent that unevenness can be formed, and the speed should be set appropriately depending on the degree of the unevenness structure.

Figures 13(a) to (d) show another example of an apparatus suitable for use in producing the sheet of the present invention. The apparatus 50 shown in the figure is suitable for use in producing the sheet 10 shown in Figures 4(a), 4(b) and 4(c), for example.

In the device 50 shown in FIG. 13(a), multiple partition walls 52 are arranged in parallel at regular intervals on the main surface of a flat substrate 51. This device 50 is used as a member for forming uneven surfaces in a sheet.

As shown in FIG. 13(b), a first fiber sheet 53 is placed on the partition wall 52 of the device 50 shown in FIG. 13(a). The first fiber sheet 53 can be, for example, a spunbond layer or an SNS layer.

13(c), the first fiber sheet 53 is pushed into the space between the partition walls 52 using a pushing member 54 to give the first fiber sheet 53 an uneven shape. There are no particular limitations on the type of material for the pushing member 54, so long as it is capable of pushing the first fiber sheet 53 into the space between the partition walls 52. Therefore, the pushing member 54 may be, for example, a filament-like body. Of course, the pushing member 54 may also be a rigid body such as a rod-like body.

After the first fiber sheet 53 has been formed with projections and recesses, as shown in Fig. 13(d) , the second fiber sheet 55 is placed on the first fiber sheet 53. Since the first fiber sheet 53 has been formed with projections and recesses as described above, the tops of the projections on the first fiber sheet 53 come into contact with the second fiber sheet 55. The second fiber sheet 55 can be, for example, a spunbond layer or an SNS layer.
With the second fiber sheet 55 disposed on the first fiber sheet 53, heat is applied to both sheets 53, 55 to bond the two sheets 53, 55 at the contacting portions of the two sheets 53, 55. Methods of applying heat include, for example, pressing a heater against the second fiber sheet 55, blowing hot air, and irradiating infrared rays.

Figures 14(a) to (e) show another example of an apparatus suitable for use in producing the sheet of the present invention. The apparatus 60 shown in the figure is suitable for use in producing the sheet 10 shown in, for example, Figures 4(a), 4(b), 4(c) and 6(b).

In the device 60 shown in Fig. 14(a), a plurality of columnar members 62 are arranged at regular intervals in the vertical and horizontal directions on the main surface of a flat substrate 61. This device 60 is used as a member for forming irregularities in a sheet. The columnar members 62 may be cylindrical or may be rectangular.
As shown in Fig. 14(b) , in the device 60, a shaping restricting member 63 is disposed between adjacent columnar members 62. The shaping restricting member 63 is disposed for the purpose of adjusting the degree of uneven shaping applied to the first fiber sheet 64 in the process shown in Fig. 14(d) described later.
14(b), a first fiber sheet 64 is placed on the columnar member 62 of the device 60 as shown in Fig. 14(c). The first fiber sheet 64 may be, for example, a spunbond layer or an SNS layer. Alternatively, the first fiber sheet 64 may be a carded web.

Next, as shown in FIG. 14(d), the first fiber sheet 64 is pressed into the spaces between the columnar members 62 using a pressing member 65 to form the first uneven shape on the first fiber sheet 64. The pressing member 65 may be a rigid body such as a rod-shaped body. The pressing of the first fiber sheet 64 by the pressing member 65 is adjusted to a certain degree by the shape forming restriction member 63.

Once the first fiber sheet 64 has been formed into the primary unevenness, the pushing member 65 is moved aside and the shaping control member 63 is removed. Next, as shown in FIG. 14(e), hot air is blown onto the first fiber sheet 64 to form the secondary unevenness. Hot air may be blown only once, or may be blown two or more times. When blowing hot air two or more times, it is preferable to set the hot air temperature the same for the first and second or subsequent blows and to set the hot air speed slower than the first blow, as this allows for clear unevenness to be formed.

Once the first fiber sheet 64 has been shaped to have projections and recesses in this manner, a second fiber sheet (not shown) is placed on the first fiber sheet 64 in the same manner as in the procedure shown in FIG. 13(d) described above. The second fiber sheet can be, for example, a spunbond layer or an SNS layer. Thereafter, the first fiber sheet and the second fiber sheet are joined in the same manner as in the procedure shown in FIG. 13(d) described above to obtain the desired sheet. Note that a hot melt adhesive can also be used to join the first fiber sheet and the second fiber sheet.

Another example of a suitable apparatus used for producing the sheet of the present invention is shown in Figures 15 and 16. The apparatus 70 shown in Figure 16 is suitable for producing the sheet 10 shown in Figure 10, for example.
16, a manufacturing method of the sheet 10 using the manufacturing apparatus 70 includes a joining step of partially joining a first fiber sheet 23A, which is an original roll of the first nonwoven fabric layer 23, and a second fiber sheet 24A, which is an original roll of the second nonwoven fabric layer 24, to obtain the sheet 10. Specifically, the manufacturing method preferably includes a step of overlapping the second fiber sheet 24A, which has elasticity, on one side of the first fiber sheet 23A while the second fiber sheet 24A is in a stretched state, and a step of partially joining both sheets 23A, 24A.

The method for manufacturing the sheet 10 using the manufacturing apparatus 70 preferably includes a precursor manufacturing step of manufacturing a composite material 24B, which is a precursor of the second fiber sheet 24A, as shown in FIG. 15, as the raw material for the second nonwoven fabric layer 24, and an elasticity developing step of stretching the composite material 24B to obtain the second fiber sheet 24A, which is the raw material for the second nonwoven fabric layer 24, as shown in FIG. 16.

In the precursor manufacturing process, as shown in FIG. 15, it is preferable to bond a plurality of elastic filaments 25 to the nonwoven fabrics 26, 26 so as to extend in one direction and in a substantially unstretched state, to obtain a composite material 24B, which is a precursor of the second fiber sheet 24A. More specifically, it is preferable to weld the elastic filaments 25 to the two nonwoven fabrics 26, 26 so that the elastic filaments 25 are arranged in one direction without crossing each other before solidification, while drawing out a large number of molten elastic filaments 25 spun from the spinning nozzle 86 at a predetermined speed. In this way, a composite material 24B is manufactured as a precursor of the second fiber sheet 24A, in which a plurality of elastic filaments 25 are bonded to the nonwoven fabrics 26, 26 over their entire length in a substantially unstretched state.

In the stretchability development treatment step in this embodiment, a groove-drawing device 75 is used to perform a drawing treatment on the composite material 24B serving as a precursor of the second fiber sheet 24A.
This stretching process is a process for stretching the composite material 24B along the extending direction of the elastic filaments 25 to impart extensibility to both nonwoven fabrics 26, 26. The imparting of extensibility here also includes a case where the extensibility of the nonwoven fabric 26, which already has some extensibility, is greatly improved.

It is preferable that the tooth groove extension device 75 has teeth, which are axially extending convex portions, and grooves formed between the teeth and extending in the axial direction, which are alternately arranged in the circumferential direction, and is provided with a pair of tooth groove rolls 76, 77 that mesh with each other.
In the elasticity developing treatment step using the tooth groove stretching device 75, the composite material 24B obtained in the precursor manufacturing step is supplied between a pair of tooth groove rolls 76, 77, and the composite material 24B is stretched to obtain a second fiber sheet 24A in which the nonwoven fabrics 26, 26 contained in the composite material 24B are stretchable. In order to effectively perform the stretching, it is preferable to arrange a first nip roll 88 on the upstream side of the tooth groove stretching device 75 and a second nip roll 89 on the downstream side of the tooth groove stretching device 75, and to perform the elasticity developing treatment step under a state in which tension is applied to the composite material 24B.
As the tooth profile of the tooth groove rolls 76, 77, a general involute tooth profile or cycloid tooth profile is used, and in particular, those having a narrow tooth width are preferable.

In this manner, the composite material 24B is partially stretched by the pair of grooved rolls 76, 77, etc., to obtain the second fiber sheet 24A. The obtained second fiber sheet 24A exhibits elasticity along the extension direction of the elastic filaments 25.
Figures 15 and 16 show a case in which the composite material 24B is wound into a roll to form a roll-shaped object 24R, and then the composite material 24B unwound from the roll-shaped object 24R is subjected to a stretching process. However, the manufactured composite material 24B may also be introduced into a groove stretching device using groove rolls 76, 77 without being wound into a roll.
As shown in FIG. 16, the first fiber sheet 23A can be used by unwinding it from a roll 23R of the first fiber sheet 23A.
The above describes a method of stretching the composite material 24B using the grooved rolls 76, 77 to impart elasticity to the composite material 24B. However, instead of this method, it is also possible to produce the second fiber sheet 24A by using an elastic nonwoven fabric as the second fiber sheet without using the grooved rolls and bonding the nonwoven fabric in a stretched state.

In the joining process in this embodiment, it is preferable that a joining process is performed on the laminated sheet 10A, in which the second fiber sheet 24A and the first fiber sheet 23A in an extended state are stacked, to partially join the first fiber sheet 23A and the second fiber sheet 24A.
For the joining process, any device capable of partially joining the first fiber sheet 23A and the second fiber sheet 24A can be used, such as a heat sealing device, an ultrasonic sealing device, or a high-frequency sealing device.
16 shows a state in which the first fiber sheet 23A and the second fiber sheet 24A are partially bonded together using an ultrasonic sealing device 71A. The ultrasonic sealing device 71A includes an ultrasonic horn 72 and an anvil roll 71 disposed opposite the horn 72. The laminated sheet 10A is transported along the circumferential surface of the anvil roll 71. During the transport process, the laminated sheet 10A is irradiated with ultrasonic waves by the ultrasonic horn 72, thereby partially bonding the second fiber sheet 24A and the first fiber sheet 23A together.

In the manufacture of the sheet of the present invention using the above-mentioned devices 30, 40, 50, 60, and 70 shown in Figures 11 to 16, a water repellent agent can be applied to the sheet 10 after manufacture. Alternatively, a water repellent agent can be applied to the raw roll before manufacture. By applying a water repellent agent, the leakproofness of the sheet of the present invention is further improved. A water repellent agent may be added to the resin used when spinning the spunbond nonwoven fabric, meltblown nonwoven fabric, or electrospun nonwoven fabric. The water repellent agent added to the resin bleeds out, imparting water repellency to the fiber surface.
Examples of the water repellent include nonionic water repellents, anionic water repellents, cationic water repellents, amphoteric water repellents, silicone water repellents, fluorine compound water repellents, and oils and fats. As long as the effects of the present invention are achieved, the water repellent is not limited to these water repellents, but from the viewpoint of water repellency, it is preferable to use fluorine compound water repellents and oils and fats. As the oils and fats, triglycerides are preferable, and palmitic acid triglyceride, stearic acid triglyceride, palm extremely hardened oil, and high erucic rapeseed hardened oil are more preferable.

Although the present invention has been described based on the preferred embodiment, the present invention is not limited to the above embodiment.
For example, in the embodiment shown in Figures 4 to 10, the first surface 21 of the sheet 10 has an uneven structure and the second surface 22 is a flat surface, but instead, both the first surface 21 and the second surface 22 may have an uneven structure.

In relation to the above-mentioned embodiment, the present invention further discloses the following sheet for absorbent articles.
＜1＞
A sheet for absorbent articles comprising a plurality of nonwoven fabric layers laminated together,
At least one surface of the sheet has a concave-convex structure,
A sheet for absorbent articles, which has water repellency against liquids with a surface tension of 60 mN/m.

＜2＞
The absorbent article sheet according to <1> above, which has water repellency against a liquid having a surface tension of preferably 50 mN/m, and more preferably 40 mN/m.
＜3＞
The absorbent article sheet according to <1> or <2>, wherein on one surface of the sheet, convex portions and concave portions are alternately arranged along one direction, and convex portions and concave portions are alternately arranged along a direction perpendicular to the one direction.
＜4＞
The absorbent article sheet according to <1> or <2>, wherein convex portions extending continuously in stripes along one direction on one surface of the sheet and concave portions extending continuously in stripes along the one direction are alternately arranged along a direction perpendicular to the one direction.
＜5＞
The sheet for absorbent articles according to any one of <1> to <4>, wherein the width of the convex portions in the concave-convex structure is 0.5 mm or more and 8 mm or less.
＜6＞
The width of the convex portion in the concave-convex structure is preferably 1 mm or more, and more preferably 1.5 mm or more.
The absorbent article sheet according to <5> above, wherein the width of the convex portions in the concave-convex structure is preferably 6 mm or less, and more preferably 4 mm or less.

＜７＞
The pitch of the convex portions in the concave-convex structure is preferably 1 mm or more, more preferably 1.5 mm or more, and even more preferably 2 mm or more.
The sheet for absorbent articles described in any one of <1> to <6>, wherein the pitch of the convex portions in the uneven structure is preferably 10 mm or less, more preferably 9 mm or less, and even more preferably 8 mm or less.
＜8＞
The height of the convex portions in the concave-convex structure is preferably 0.5 mm or more, more preferably 0.7 mm or more, and even more preferably 0.9 mm or more.
The height of the convex portions in the uneven structure is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. The absorbent article sheet according to any one of <1> to <7>.
＜9＞
The absorbent article sheet according to any one of <1> to <8>, wherein the inside of the convex portions in the concave-convex structure is solid.
＜10＞
The absorbent article sheet according to any one of <1> to <8>, wherein the inside of the protrusions in the uneven structure is hollow.
<11>
The sheet for absorbent articles according to any one of <1> to <10>, comprising a nanofiber layer.

＜12＞
The sheet for absorbent articles according to <11> above, wherein the nanofiber layer has an uneven structure.
＜13＞
The absorbent article sheet according to <11> or <12>, wherein a part or the whole of the nanofiber layer is located on one side of the halfway point in the thickness direction.
＜14＞
The absorbent article sheet according to <13>, wherein the entirety of the nanofiber layer is located on one side of the halfway point in the thickness direction.
＜15＞
The absorbent article sheet according to any one of <11> to <14>, comprising the nanofiber layer having fibers with a fiber diameter of 1 μm or less as constituent fibers.
＜16＞
The fiber diameter of the constituent fibers of the nanofiber layer is preferably 1 μm or less, and more preferably 0.9 μm or less.
The absorbent article sheet according to any one of <11> to <15>, wherein the fiber diameter of the constituent fibers of the nanofiber layer is preferably 0.4 μm or more.

＜１７＞
The sheet for absorbent articles according to any one of <11> to <16>, wherein the nanofiber layer has a thickness of preferably 3 μm or more and 150 μm or less, more preferably 10 μm or more and 120 μm or less, and even more preferably 15 μm or more and 100 μm or less.
＜18＞
In addition to the nanofiber layer, another nonwoven fabric layer is provided,
The absorbent article sheet according to any one of <11> to <17>, wherein the other nonwoven fabric layer has elasticity.
＜19＞
The nanofiber layer is a meltblown layer,
The absorbent article sheet according to any one of <11> to <18>, wherein the meltblown layer is disposed between a pair of spunbond layers.
＜20＞
The sheet for absorbent articles described in <19>, wherein the SNS layer formed by disposing the meltblown layer between a pair of the spunbond layers constitutes the uneven structure.
＜21＞
The sheet for absorbent articles according to any one of <1> to <20> above, which has an air-through layer.

＜22＞
The SNS layer has a nanofiber layer disposed between a pair of spunbond layers,
The absorbent article sheet according to <21>, wherein an air-through layer is disposed on an outer surface of at least one of the pair of spunbond layers in the SNS layer.
＜23＞
The sheet for absorbent articles according to <21> or <22>, wherein the air-through layer constitutes the uneven structure.
＜24＞
The absorbent article sheet according to <21> or <22>, wherein the air-through layer is present in a portion other than the uneven structure.
＜25＞
The air-through layer is disposed on each side of the nanofiber layer,
Each of the nanofiber layer and the air-through layer protrudes toward one surface side of the sheet to form a convex portion,
The absorbent article sheet according to any one of <21> to <24>, wherein the inside of the protrusions is solid.
＜26＞
The sheet for absorbent articles according to any one of <21> to <25>, wherein the air-through layer contains crimped fibers.

＜27＞
A first surface and a second surface located opposite the first surface,
The first surface side has an uneven structure,
The second surface is a flat surface,
A single spunbond layer is located on the first surface side,
The spunbond layer forms protrusions and recesses,
The inside of the protrusion is hollow,
A SNS layer including a spunbond layer, a nanofiber layer, and a spunbond layer is located on the second surface side,
The sheet for absorbent articles according to any one of <1> to <26>, wherein each surface of the SNS layer is a flat surface.
＜28＞
A first surface and a second surface located opposite the first surface,
A SNS layer including a spunbond layer, a nanofiber layer, and a spunbond layer is located on the first surface side,
The SNS layer comprises a convex portion 11 and a concave portion 12,
The inside of the protrusion is hollow,
A single spunbond layer is located on the second surface side,
The absorbent article sheet according to any one of <1> to <26>, wherein each surface of the spunbond layer is flat.
＜29＞
A first surface and a second surface located opposite the first surface,
A first SNS layer consisting of a spunbond layer, a nanofiber layer and a spunbond layer is located on the first surface side,
The first SNS layer comprises a convex portion and a concave portion,
The inside of the protrusion is hollow,
A second SNS layer consisting of a spunbond layer, a nanofiber layer and a spunbond layer is located on the second surface side,
The sheet for absorbent articles according to any one of <1> to <26>, wherein each surface of the second SNS layer is a flat surface.
＜30＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
The structure has an air-through layer disposed on each side of the nanofiber layer,
The nanofiber layer and the pair of air-through layers each have a convex portion protruding toward the first surface side,
The inside of the protrusion is solid,
the inside of the protrusion is filled mainly with constituent fibers of the air-through layer located on the second surface side,
Of the pair of air-through layers, the air-through layer located on the second surface side has a flat outer surface,
The absorbent article sheet according to any one of <1> to <26>, wherein the nanofiber layer and the pair of air-through layers are compressed and integrally joined in the recesses of the sheet.
＜31＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
An air-through layer is located on the first surface side,
The air-through layer has a convex portion and a concave portion,
The inside of the protrusion is solid,
A SNS layer is located on the second surface side, the SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The SNS layer has flat surfaces on each side,
The sheet for absorbent articles described in any one of <1> to <26>, wherein the air-through layer is compressed and integrally joined to the SNS layer located on the second surface side at the recess.

＜32＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
An air-through layer is located on the first surface side,
The air-through layer has a convex portion and a concave portion,
The inside of the protrusion is hollow,
A SNS layer is located on the second surface side, the SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The SNS layer has flat surfaces on each side,
The sheet for absorbent articles described in any one of <1> to <26>, wherein the air-through layer is compressed and integrally joined to the SNS layer located on the second surface side at the recess.
＜33＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
A SNS layer is located on the first surface side, the SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The SNS layer comprises a convex portion and a concave portion,
An air-through layer is located on the second surface side,
The air-through layer has a flat outer surface,
The surface of the air-through layer facing the SNS layer has an uneven structure,
The uneven structure has a shape complementary to the uneven structure formed by the SNS layer,
The inside of the protrusion is solid,
The inside of the protrusion is filled with the constituent fibers of the air-through layer,
The SNS layer is compressed and integrally joined to the air-through layer located on the second surface side at the recessed portion.
＜34＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
A SNS layer is located on the first surface side, the SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The SNS layer comprises a convex portion and a concave portion,
An air-through layer is located on the second surface side,
The air-through layer has a flat outer surface,
The surface of the air-through layer facing the SNS layer has an uneven structure,
The fibers constituting the air-through layer are present inside the protrusions,
the constituent fibers of the air-through layer do not completely fill the inside of the protrusions, and spaces exist inside the protrusions, making the inside of the protrusions hollow;
The SNS layer is compressed and integrally joined to the air-through layer located on the second surface side at the recessed portion.
＜35＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
The SNS layer is formed by disposing a nanofiber layer between a pair of spunbond layers, and an air-through layer is disposed on each side of the SNS layer.
The SNS layer and the pair of air-through layers each have a convex portion protruding toward the first surface side,
The inside of the protrusion is solid,
the inside of the protrusion is filled mainly with constituent fibers of the air-through layer located on the second surface side,
The air-through layer located on the second surface side has a flat outer surface,
The absorbent article sheet according to any one of <1> to <26>, wherein the SNS layer and the pair of air-through layers are consolidated and integrally joined in the recesses of the sheet.
＜36＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
A first SNS layer is located on the first surface side, the first SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The first SNS layer comprises a convex portion and a concave portion,
A second SNS layer is located on the second surface side, the second SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The second SNS layer has flat surfaces on each side,
An air-through layer is disposed between the first SNS layer and the second SNS layer,
The air-through layer is located within the convex portion so as to fill the entire space of the convex portion defined by the first SNS layer and the second SNS layer,
The inside of the protrusion is solid,
The absorbent article sheet according to any one of <1> to <26>, wherein the inside of the protrusions is filled with constituent fibers of the air-through layer.

＜３７＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
A first SNS layer is located on the first surface side, the first SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The first SNS layer comprises a convex portion and a concave portion,
A second SNS layer is located on the second surface side, the second SNS layer being formed by disposing a nanofiber layer between a pair of spunbond layers,
The second SNS layer has flat surfaces on each side,
An air-through layer is disposed between the first SNS layer and the second SNS layer,
The air-through layer has constituent fibers present inside a convex portion defined by the first SNS layer and the second SNS layer,
The absorbent article sheet according to any one of <1> to <26>, wherein the constituent fibers of the air-through layer do not completely fill the insides of the protrusions, and spaces exist inside the protrusions, making the insides of the protrusions hollow.
＜３８＞
A first surface and a second surface located opposite the first surface,
The first surface has an uneven structure,
The second surface is a flat surface,
A first nonwoven fabric layer having a concave-convex structure is located on the first surface side,
A second nonwoven fabric layer 24 is located on the second surface side,
The first nonwoven fabric layer defines a protrusion and a recess,
The inside of the protrusion is hollow,
the first nonwoven fabric layer is a nanofiber layer or a nonwoven fabric layer containing a nanofiber layer;
The second nonwoven fabric layer has flat surfaces on each side,
The second nonwoven fabric layer is a nonwoven fabric containing elastic filaments and inelastic fibers,
The absorbent article sheet according to any one of <1> to <26>, wherein the second nonwoven fabric layer is bonded to a nonwoven fabric containing the inelastic fibers in a substantially unstretched state by the elastic filaments.
＜３９＞
An absorbent article comprising an absorbent body and the sheet for absorbent articles according to any one of <1> to <38>,
The sheet for absorbent articles is disposed so that the surface of the sheet for absorbent articles having the uneven structure faces the absorbent body.
＜40＞
The sheet for absorbent articles has a nanofiber layer,
The absorbent article according to <39>, further comprising a nonwoven fabric layer on a non-skin-facing side of the nanofiber layer, the nonwoven fabric layer being flatter than the skin-facing side.
＜41＞
The absorbent article according to <40> above, further comprising an air-through layer on the skin-facing side of the nanofiber layer.
＜42＞
The absorbent article according to any one of <39> to <41>, wherein the sheet for absorbent articles is disposed on a non-skin facing side of the absorbent body.

The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, "%" means "% by mass."

Example 1
In this example, the apparatus shown in FIG. 11 was used to manufacture a sheet for absorbent articles having the structure shown in FIG. 2 and FIG. 7(b).
(1) Production of carded web A carded web having a basis weight of 27 g/m2 was produced using eccentric sheath-core conjugate fibers having a core made of low-density polyethylene (hereinafter also referred to as "LDPE") and a sheath made of polyethylene (hereinafter also referred to as "PE" ⁾ . This eccentric sheath-core conjugate fiber had a fineness of 2.3 dtex and a fiber length of 51 mm. This eccentric sheath-core conjugate fiber is a latent crimp fiber that develops crimp when heat is applied.
(2) Production of SNS Web A meltblown nonwoven fabric made of PP fibers and having a basis weight of 5 g/ ^m2 was laminated on a spunbond nonwoven fabric made of polypropylene (hereinafter also referred to as "PP") fibers having an average fiber diameter of 20 μm and having a basis weight of 9 g/ ^m2 , and a spunbond nonwoven fabric made of PP fibers having an average fiber diameter of 20 μm and having a basis weight of 9 g/ ^m2 was further laminated on top of that to produce an SNS web having a three-layer structure. The fiber diameter of the constituent fibers of the meltblown nonwoven fabric was 0.8 μm.
(3) Bonding of card web and SNS web An SNS web, which was continuously transported in one direction, was superimposed on a card web, which was continuously transported in the same direction, and the two were bonded by ultrasonic embossing. The linear pressure of the ultrasonic embossing was set to 60 N/cm. A sheet precursor was obtained in this way. The shape of the bonded portion was a cross shape.
(4) Heat treatment of sheet precursor While both side edges of the sheet precursor continuously conveyed in one direction were fixed by pin tenters, hot air was blown onto the sheet precursor by the air-through method. This caused the eccentric core-sheath type composite fibers constituting the carded web to develop crimps and shrink. As a result, many convex portions were formed on the SNS web. In this way, a sheet for absorbent articles having the structure shown in Figure 7 (b) was obtained. This sheet for absorbent articles had elasticity.
The temperature of the hot air was set to 105° C., and the speed of the hot air was set to 1.7 m/sec. The shrinkage rate of the sheet precursor was 80% in the conveying direction and 90% in the direction perpendicular to the conveying direction.
(5) Addition of Water Repellent An ethanol solution (concentration 1%) of Asahi Guard AG-E082, a fluorine-based water and oil repellent available from AGC Inc., was prepared. The absorbent article sheet obtained in (4) was immersed in this ethanol solution, and then annealed and dried at 80° C. for 2 hours to add the water repellent to the sheet.

Example 2
In Example 1, the fiber diameter of the constituent fibers of the meltblown nonwoven fabric in the SNS web was set to 2 μm. Except for this, a sheet for absorbent articles having the structure shown in Fig. 2 and Fig. 7(b) was obtained in the same manner as in Example 1. This sheet for absorbent articles had elasticity.

Example 3
In this example, the apparatus shown in FIG. 11 was used to manufacture a sheet for absorbent articles having the structure shown in FIG. 2 and FIG.
(1) Production of carded web The same as in Example 1 was carried out.
(2) Production of Meltblown Composite Web A meltblown composite web having a two-layer structure was produced by laminating a meltblown nonwoven fabric having a basis weight of 5 g/ ^m2 made of PP fiber on an air-through nonwoven fabric having a basis weight of 9 g/ ^m2 made of core-sheath composite fiber with a core made of polyethylene terephthalate and a sheath made of PE. The fiber diameter of the constituent fibers of the meltblown nonwoven fabric was 0.8 μm.
The core-sheath type composite fiber constituting the air-through nonwoven fabric had a fineness of 2.4 dtex and a fiber length of 51 mm.
(3) Bonding of the carded web and the meltblown composite web The meltblown composite web, which was continuously transported in one direction, was superposed on the carded web, which was continuously transported in the same direction. The superposition was performed so that the meltblown nonwoven fabric in the meltblown composite web faced the carded web. The rest was the same as in Example 1.
(4) Heat Treatment of Sheet Precursor The same as in Example 1 was carried out.
(5) Addition of Water Repellent Agent The same procedure was carried out as in Example 1. The sheet for absorbent articles thus obtained had stretchability.

Example 4
In this example, the apparatus shown in FIG. 13 was used to manufacture a sheet for absorbent articles having the structure shown in FIG. 3 and FIG. 4(b).
(1) Production of SNS Web A meltblown nonwoven fabric made of PP fiber with a basis weight of 5 g/ ^m2 was laminated on a spunbonded nonwoven fabric made of PP fiber with an average fiber diameter of 20 μm with a basis weight of 9 g/ ^m2 , and a spunbonded nonwoven fabric made of PP fiber with an average fiber diameter of 20 μm with a basis weight of 9 g/ ^m2 was further laminated on the meltblown nonwoven fabric to produce an SNS web having a three-layer structure. The fiber diameter of the constituent fibers of the meltblown nonwoven fabric was 0.8 μm. The three were bonded by ultrasonic embossing. The linear pressure of the ultrasonic embossing was set to 60 N/cm.
(2) Forming unevenness in SNS web Using the apparatus 50 shown in FIG. 13(a), an SNS web was formed into unevenness in the procedure shown in FIG. 13(b) and FIG. 13(c).
(3) Lamination of spunbond webs In the procedure shown in Fig. 13(d), a spunbond web having a basis weight of 9 g/ ^m2 and made of PP fibers having an average fiber diameter of 20 µm was placed on the SNS web having the irregularities formed thereon. Next, a heater heated to 155°C was pressed against the spunbond nonwoven fabric to bond the spunbond web and the SNS web.
(4) Addition of Water Repellent Agent The same procedure was carried out as in Example 1. The sheet for absorbent articles thus obtained had no stretchability.

Example 5
In this example, the apparatus shown in FIG. 14 was used to manufacture a sheet for absorbent articles having the structure shown in FIG. 2 and FIG. 6(b).
(1) Production of carded web A carded web was produced using a core-sheath type composite fiber having a fineness of 1.8 dtex. The core of the core-sheath type composite fiber was made of polyethylene terephthalate (hereinafter also referred to as "PET") and the sheath was made of PE. The mass ratio of the core to the sheath was 5:5.
(2) Primary unevenness formation on card web Using the device 60 shown in Fig. 14(a) and Fig. 14(b), the card web was primarily unevenly formed in the manner shown in Fig. 14(c) and Fig. 14(d). The pressing depth of the pressing member 65 was set to 2 mm.
(3) Secondary unevenness formation of carded web Hot air was blown onto the carded web in the procedure shown in Fig. 14(e) to form secondary unevenness. Hot air was blown twice. The first blowing was performed under the conditions of a temperature of 160°C, a wind speed of 68 m/sec, and a blowing time of 5 seconds. The second blowing was performed under the conditions of a temperature of 160°C, a wind speed of 6.0 m/sec, and a blowing time of 5 seconds. The carded web after unevenness formation had a constituent fiber fineness of 1.8 dtex and a basis weight of 40 g/ ^m2 .
(4) Lamination of SNS Webs A meltblown nonwoven fabric made of PP fibers and having a basis weight of 5 g/ ^m2 was laminated on a spunbonded nonwoven fabric made of PP fibers and having a basis weight of 9 g/ ^m2 with an average fiber diameter of 20 μm, and a spunbonded nonwoven fabric made of PP fibers and having a basis weight of 9 g/ ^m2 with an average fiber diameter of 20 μm was further laminated on the meltblown nonwoven fabric to produce an SNS web having a three-layer structure. The fiber diameter of the constituent fibers of the meltblown nonwoven fabric was 0.8 μm. After applying a hot melt adhesive to the above-mentioned card web, an SNS web was placed on the applied surface, and the SNS web and the card web were joined together.
(5) Addition of Water Repellent Agent The same procedure was carried out as in Example 1. The sheet for absorbent articles thus obtained had no stretchability.

Example 6
In Example 1, the joining pattern between the card web and the SNS web was changed, and the width and pitch of the convex portions were changed. Except for this, a sheet for absorbent articles having the structure shown in Fig. 2 and Fig. 7(b) was obtained in the same manner as in Example 1. The sheet for absorbent articles obtained in this manner had stretchability.

Example 7
In Example 1, fibers that do not develop crimps when heat is applied were used as the fibers used in producing the carded web. Except for this, a sheet for absorbent articles having the structure shown in Fig. 2 and Fig. 7(b) was obtained in the same manner as in Example 1. The sheet for absorbent articles thus obtained had no stretchability.

Example 8
In Example 1, the joining pattern between the card web and the SNS web was changed, and the width and pitch of the convex portions were changed. Except for this, a sheet for absorbent articles having the structure shown in Fig. 3 and Fig. 7(b) was obtained in the same manner as in Example 1. The sheet for absorbent articles obtained in this manner had stretchability.

Example 9
In this example, a sheet having the structure shown in FIG. 10 was manufactured according to the method shown in FIGS.
(1) Preparation of First Fiber Sheet A spunbond nonwoven fabric made of PP resin having an average fiber diameter of 15 μm and a basis weight of 18 g/m ² was prepared.
(2) Manufacturing of the first fiber sheet A nanofiber layer made of PP resin was formed on one surface of the spunbond nonwoven fabric by electrospinning. The nanofiber layer had a basis weight of 3 g/ ^m2 and an average fiber diameter of 500 nm.
(3) Production of second fiber sheet Two sheets of spunbond nonwoven fabric made of PP resin with an average fiber diameter of 18 μm and a basis weight of 18 g/ ^m2 were used, and a plurality of elastic filaments with a diameter of 100 μm were arranged between the two nonwoven fabrics to produce a composite material 24B shown in Fig. 15. The total basis weight of the elastic filaments was 9 g/ ^m2 relative to the area of the composite material 24B. The composite material 24B was passed between a pair of grooved rolls 76 and 77 shown in Fig. 16 to develop elasticity, producing a second fiber sheet 24A.
(4) Manufacturing of Sheet According to the method shown in FIG. 16, the first fiber sheet 23A having the nanofiber layer and the second fiber sheet 24A were overlapped and bonded together while the second fiber sheet 24A was in an elongated state, to manufacture a sheet.

Comparative Example 1
(1) Production of SNS Web A meltblown nonwoven fabric made of PP fiber with a basis weight of 5 g/ ^m2 was laminated on a spunbonded nonwoven fabric made of PP fiber with an average fiber diameter of 20 μm with a basis weight of 9 g/ ^m2 , and a spunbonded nonwoven fabric made of PP fiber with an average fiber diameter of 20 μm with a basis weight of 9 g/ ^m2 was further laminated on the meltblown nonwoven fabric to produce an SNS web having a three-layer structure. The fiber diameter of the constituent fibers of the meltblown nonwoven fabric was 0.8 μm. The three were bonded by ultrasonic embossing. The linear pressure of the ultrasonic embossing was set to 60 N/cm.
(2) Addition of Water Repellent Agent The same procedure was carried out as in Example 1. The sheet for absorbent articles thus obtained had no stretchability.

Comparative Example 2
The SNS web obtained in Comparative Example 1 was pressed with a concave-convex shaping press equipped with a pair of mutually interlocking shaping plates. The pressing pressure was 0.4 MPa. Except for this, a sheet for absorbent articles was obtained in the same manner as in Comparative Example 1. The sheet for absorbent articles thus obtained had no stretchability.

〔evaluation〕
For the absorbent article sheets obtained in the Examples and Comparative Examples, the width W, height H, and pitch P of the protrusions were measured by the above-mentioned method. In addition, the water repellency against low surface tension liquid was evaluated by the above-mentioned method. The results are shown in Table 1.
Furthermore, the degree of penetration of the low surface tension liquid into the meltblown layer was evaluated by the method described below. The results are shown in Table 1.
Furthermore, the absorbent sheets obtained in the Examples and Comparative Examples were incorporated into sanitary napkins, and a dynamic seepage test was carried out according to the following procedure, and the leakproofness was evaluated according to the following criteria. The results are shown in Table 1.

[Dynamic Exudation Test]
The back sheet of Kao Corporation's sanitary napkin "LAURIER (registered trademark) F Happy Bare Skin Super Slim Daytime" (manufactured in 2019, 22.5 cm) was carefully removed using cold spray. In place of the removed back sheet, the absorbent article sheets obtained in the Examples and Comparative Examples were adhered to the absorbent body with hot melt. The absorbent article sheets were arranged so that the first surface having an uneven structure faced the absorbent body. A hot melt adhesive was applied to the non-skin side of the absorbent article sheet to secure the napkin to the shorts.
The sanitary napkin thus obtained was placed horizontally with the topsheet facing vertically upward, and in this state, an elliptical injection port (major axis 50 mm, minor axis 23 mm) was placed on the topsheet. 6.0 g of defibered horse blood with adjusted viscosity was injected through the elliptical injection port and allowed to stand for 1 minute. The defibered horse blood was manufactured by Nippon Biotest Co., Ltd., and its viscosity was adjusted to 8 cp at a liquid temperature of 25°C. The viscosity was measured using a TVB-10M viscometer manufactured by Toki Sangyo Co., Ltd., using a rotor with the rotor name L/AdP (rotor code 19) at a rotation speed of 12 rpm.
The sanitary napkin into which the fiber-free horse blood had been injected was attached to a movable female waist model shown in Fig. 9 of JP-A-9-187476, and shorts were then attached over the sanitary napkin. After the model was made to walk at a speed of 100 steps/min for one hour, the shorts and sanitary napkin were removed and visually observed to see whether or not horse blood had seeped out of the shorts.
When the absorbent sheets obtained in the Examples and Comparative Examples were incorporated into a napkin, the uneven surface of the sheet was made to face the absorbent body, except for the sheet obtained in Example 6, in which the uneven surface faced the outer surface of the napkin.

[Degree of penetration into meltblown layer]
After the dynamic seepage test, the sanitary napkin was removed from the shorts. The non-skin side of the absorbent article sheet in the removed sanitary napkin was visually observed. When horse blood was found to have reached the surface of the non-skin side of the absorbent article sheet, the number of spots was visually counted. When horse blood had not reached the surface of the non-skin side of the absorbent article sheet, 10 sites were selected where the redness of the horse blood looked darker than the surroundings when the absorbent article sheet was visually observed from the non-skin side. Each site was cut in the thickness direction from the non-skin side with a razor or the like, and the cross section was observed under a microscope. When horse blood had seeped into the entire thickness direction of the meltblown layer, the number of spots where the horse blood had seeped into the meltblown layer was counted.

As is clear from the results shown in Table 1, the sheets for absorbent articles obtained in each Example have water repellency against low surface tension liquids.
It is also evident that when the sheets for absorbent articles obtained in the respective Examples are used as the backsheet of a sanitary napkin, the seepage of liquid is prevented.

REFERENCE SIGNS LIST 10: Sheet for absorbent article 11: Convex portion 12: Concave portion 13: Spunbond layer 14: Meltblown layer 15: SNS layer 16: Bonded portion 17: Air-through layer 21: First surface 22: Second surface

Claims (12)

A sheet for absorbent articles comprising a plurality of nonwoven fabric layers laminated together,
The nonwoven fabric layers include an SNS layer in which a nanofiber layer is disposed between a pair of spunbond layers, and an air-through layer located on an outer surface of at least one of the pair of spunbond layers in the SNS layer,
The fiber diameter of the constituent fibers of the nanofiber layer is 0.4 μm or more and 1 μm or less,
The absorbent article sheet has a first surface on which the SNS layer is located and a second surface on which the air-through layer is located,
The sheet for absorbent articles has an uneven structure on the first surface side , and the SNS layer constitutes a convex portion and a concave portion,
The surface of the air-through layer facing the SNS layer has an uneven structure, and fibers constituting the air-through layer are present inside the protrusions,
The outer surface of the air-through layer is flat,
A sheet for absorbent articles, which has water repellency against liquids with a surface tension of 60 mN/m. The absorbent article sheet according to claim 1, wherein the width of the convex portions in the uneven structure is 0.5 mm or more and 8 mm or less. The absorbent sheet according to claim 1 or 2, wherein the insides of the protrusions are filled with constituent fibers of the air-through layer . The absorbent article sheet according to claim 1 or 2 , wherein the insides of the protrusions are not completely filled with the constituent fibers of the air-through layer, and spaces exist inside the protrusions . 5. The absorbent article sheet according to claim 1, wherein on one surface of the sheet, convex portions and concave portions are alternately arranged along one direction, and convex portions and concave portions are alternately arranged along a direction perpendicular to the one direction. The sheet for absorbent articles according to claim 1 , wherein the nanofiber layer is a meltblown layer. 5. The absorbent article sheet according to claim 1, wherein convex portions extending continuously in stripes along one direction on one surface of the sheet and concave portions extending continuously in stripes along the one direction are alternately arranged in a direction perpendicular to the one direction . The sheet for absorbent articles according to claim 1 , wherein the air-through layer comprises crimped fibers. The absorbent article sheet according to claim 1 , wherein the pitch of the projections in the uneven structure is from 1 mm to 10 mm . The absorbent article sheet according to claim 1 , wherein the nanofiber layer has a thickness of 3 μm or more and 150 μm or less . An absorbent article comprising an absorbent body and the sheet for absorbent articles according to any one of claims 1 to 10 ,
The sheet for absorbent articles is arranged so that the surface of the SNS layer having the uneven structure in the sheet for absorbent articles faces the absorbent body. The absorbent article according to claim 11 , wherein the sheet for absorbent articles is disposed on a non-skin facing side of the absorbent body.

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