Sheet member and absorbent article

Abstract

To provide a sheet member that reduces discomfort and poor influence on a wearer's skin.SOLUTION: Provided is a sheet member 25 for an absorbent article with a skin side layer 25a capable of coming into contact with a wearer's skin, and a non-skin side layer 25b provided on a non-skin side of the skin side layer 25a. In the sheet member 25, the hydrophilicity of a skin side fiber 25as, which is a base material fiber of the skin side layer 25a, is higher than that of a non-skin side fiber 25bs, which is a base material fiber of the non-skin side layer 25b; and the skin side layer 25a has a predetermined basis weight part 25aP with the skin side fiber 25as having a predetermined basis weight, and a low basis weight part 25aL having a basis weight of the skin side fiber 25as lower than that of the predetermined basis weight part 25aP, and when viewed in a thickness direction, has a portion where the predetermined basis weight part 25aP overlaps with the non-skin side layer 25b, and a portion where the low basis weight part 25aL overlaps with the non-skin side layer 25b.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a sheet member.

Background Art

[0002] Since the sheet member for absorbent articles comes into contact with the skin of the wearer, it absorbs moisture such as sweat of the wearer during wearing. For example, Patent Document 1 discloses a sweat-absorbing sheet formed of an inner layer made of hydrophobic fibers and an outer layer made of hydrophilic fibers. This sweat-absorbing sheet of Patent Document 1 moves the sweat absorbed from the inner layer located on the skin side to the outer layer located on the non-skin side, so that moisture does not remain on the skin side surface of the sweat-absorbing sheet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, since hydrophobic fibers have a poorer touch than hydrophilic fibers, improvement in the touch of the sweat-absorbing sheet that comes into contact with the skin side is desired. However, since hydrophilic fibers have the property of easily absorbing and retaining moisture, there has been a problem that it is difficult to provide hydrophilic fibers on the skin side surface of the sweat-absorbing sheet.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a sheet member that reduces discomfort and adverse effects on the skin of the wearer.

Means for Solving the Problems

[0006] The main invention for achieving the above object is a sheet member for an absorbent article having a skin-side layer that can contact the wearer's skin and a non-skin-side layer provided on the non-skin side of the skin-side layer, wherein the hydrophilicity of the skin-side fibers, which are the base fibers of the skin-side layer, is higher than the hydrophilicity of the non-skin-side fibers, which are the base fibers of the non-skin-side layer, and the skin-side layer has a predetermined basis weight portion provided with the skin-side fibers of a predetermined basis weight and a low basis weight portion having a lower basis weight of the skin-side fibers than the predetermined basis weight portion, and in a thickness direction view, there are a portion where the predetermined basis weight portion overlaps with the non-skin-side layer and a portion where the low basis weight portion overlaps with the non-skin-side layer. Other features of the present invention will be clarified by the description in this specification and the attached drawings.

Effect of the Invention

[0007] According to the present invention, it is possible to provide a sheet member that reduces discomfort and adverse effects on the wearer's skin.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] From the description of this specification and the accompanying drawings, at least the following matters will become clear. (Aspect 1) A sheet member for an absorbent article having a skin-side layer capable of contacting the wearer's skin and a non-skin-side layer provided on the non-skin side of the skin-side layer, wherein the hydrophilicity of the skin-side fibers, which are the base fibers of the skin-side layer, is higher than the hydrophilicity of the non-skin-side fibers, which are the base fibers of the non-skin-side layer, and the skin-side layer has a predetermined basis weight portion provided with the skin-side fibers of a predetermined basis weight and a low basis weight portion having a lower basis weight of the skin-side fibers than the predetermined basis weight portion, and in a thickness direction view, has a portion where the predetermined basis weight portion overlaps with the non-skin-side layer and a portion where the low basis weight portion overlaps with the non-skin-side layer.

[0010] According to the sheet member of Aspect 1, while improving the water absorbency and touch of the sheet member by the skin-side layer with high hydrophilicity, the water absorbed by the skin-side layer is easily moved from the low basis weight portion to the non-skin side of the sheet member, so that the possibility that the water absorbed by the sheet member continues to contact the wearer's skin can be reduced, and the discomfort and adverse effects on the wearer's skin can be reduced.

[0011] (Aspect 2) The sheet member of Aspect 1, characterized by having a portion where the skin-side fibers and the non-skin-side fibers are entangled.

[0012] According to the sheet member of Aspect 2, the flexibility of the sheet member can be improved, and the touch of the absorbent article using the sheet member can be improved.

[0013] (Aspect 3) The sheet member of Aspect 1 or 2, characterized in that the skin-side fibers are cotton fibers.

[0014] According to the sheet member of Aspect 3, since the fiber shape of the skin-side fibers of the skin-side layer that can contact the wearer's skin is round cotton fibers, the contact with the wearer's skin is good, and the irritation to the wearer's skin during wearing can be reduced.

[0015] (Aspect 4) The sheet member has a longitudinal direction and a transverse direction orthogonal to the thickness direction. In the longitudinal direction, the predetermined basis weight portion and the low basis weight portion are alternately arranged. In the transverse direction, the predetermined basis weight portion and the low basis weight portion are alternately arranged. The sheet member is any one of the sheet members of Aspects 1 to 3, characterized in that.

[0016] According to the sheet member of Aspect 4, while improving water absorption and touch feeling by the predetermined basis weight portion of the skin-side layer, it becomes easier to move the moisture absorbed in the skin-side layer from the low basis weight portion to the non-skin-side layer. Therefore, the risk that the moisture absorbed by the sheet member continues to contact the wearer's skin can be reduced, and the discomfort and adverse effects on the wearer's skin can be reduced.

[0017] (Aspect 5) The sheet member is any one of the sheet members of Aspects 1 to 4, characterized in that the density of the skin-side fibers of the low basis weight portion is lower than the density of the skin-side fibers of the predetermined basis weight portion.

[0018] According to the sheet member of Aspect 5, while improving water absorption and touch feeling by the skin-side layer, it becomes easier to move the moisture absorbed in the skin-side layer from the low basis weight portion to the non-skin-side layer. Therefore, the risk that the moisture absorbed by the sheet member continues to contact the wearer's skin can be reduced, and the discomfort and adverse effects on the wearer's skin can be reduced.

[0019] (Aspect 6) The sheet member is any one of the sheet members of Aspects 1 to 5, characterized in that at least a part of the non-skin-side fibers is present on the skin-side surface of the skin-side layer.

[0020] According to the sheet member of Aspect 6, since it becomes easier to move the liquid absorbed from the skin side layer to the non-skin side layer, it is possible to reduce the risk that the moisture absorbed by the sheet member continues to contact the skin of the wearer, and it is possible to reduce discomfort and adverse effects on the skin of the wearer.

[0021] (Aspect 7) The sheet member is any one of the sheet members of Aspects 1 to 6, characterized in that no adhesive is provided.

[0022] According to the sheet member of Aspect 7, it is possible to reduce the risk that the sheet member becomes hard, reduce the risk that moisture absorption is hindered by the adhesive, and suppress irritation to the skin of the wearer of the absorbent article using this sheet member.

[0023] (Aspect 8) The sheet member is any one of the sheet members of Aspects 1 to 7, characterized in that no portion obtained by squeezing a part of the sheet member in the thickness direction is provided.

[0024] According to the sheet member of Aspect 8, it is possible to reduce the risk that the sheet member becomes hard and suppress irritation to the skin of the wearer of the absorbent article using this sheet member.

[0025] (Aspect 9) The sheet member is any one of the sheet members of Aspects 1 to 7, characterized in that it has a sheet squeezing portion obtained by squeezing a part of the skin side layer in the thickness direction.

[0026] According to the sheet member of Aspect 9, it is possible to reduce the risk that the skin side layer and the non-skin side layer separate.

[0027] (Aspect 10) The absorbent article has a hydrophilic member provided with fibers having a higher hydrophilicity than the non-skin side fibers, and in the absorbent article, the sheet member is used on the skin side in the thickness direction and at a position overlapping the hydrophilic member when viewed in the thickness direction, and is any one of the sheet members of Aspects 1 to 9.

[0028] According to the sheet member of Aspect 10, when the absorbent article is worn, since it becomes easier to move the moisture absorbed from the sheet member side to the non-skin side, it is possible to reduce the discomfort and adverse effects caused by the continuous adhesion of moisture to the wearer's skin.

[0029] (Aspect 11) The absorbent article has a non-hydrophilic member provided with fibers having a lower hydrophilicity than the non-skin side fibers, In the absorbent article, the sheet member is used on the skin side in the thickness direction from the non-hydrophilic member and at a position overlapping the non-hydrophilic member when viewed in the thickness direction, and is a sheet member according to any one of Aspects 1 to 9.

[0030] According to the sheet member of Aspect 11, since the non-hydrophilic member is provided on the non-skin side from the non-skin side layer, when the absorbent article is worn, it is easy to suppress the transfer of moisture absorbed from the sheet member side from the non-skin side layer to the non-hydrophilic member, thus reducing the risk of the non-skin side surface of the absorbent article becoming sticky. Further, since the basis weight of the low basis weight portion is low in the basis weight of the skin side fibers, the low basis weight portion is thin in thickness and is likely to be recessed on the non-skin side, so that the risk of moisture continuously adhering to the wearer's skin can be reduced. Therefore, it becomes easier to reduce the discomfort on both the skin side and the non-skin side of the absorbent article during wearing.

[0031] (Aspect 11) The absorbent article has a stretchable member, and in the absorbent article in a deployed and extended state, the sheet member is used at a position overlapping at least a part of the stretchable member when viewed in the thickness direction, and is a sheet member according to any one of Aspects 1 to 10.

[0032] According to the sheet member of Aspect 11, while improving the touch of the absorbent article by the sheet member, by forming wrinkles in at least a part of the sheet member, the air permeability of the sheet member is improved, and the stuffiness and irritation to the skin during wearing of the absorbent article can be reduced.

[0033] (Aspect 12) The absorbent article has a squeezing member having a portion squeezed in the thickness direction. In the absorbent article, the sheet member is provided closer to the skin side than the squeezing member, and in the thickness direction, a portion where the low basis weight portion and the non-skin side layer overlap has a portion overlapping with the squeezed portion of the squeezing member, and it is the sheet member of any one of Aspects 1 to 11.

[0034] According to the sheet member of Aspect 12, since the squeezing member has a portion with a high density due to squeezing, it becomes easier for moisture to move from the sheet member to the squeezing member by capillary action.

[0035] (Aspect 13) The sheet member has a portion where the skin side fibers and the non-skin side fibers are melt-bonded, and it is the sheet member of any one of Aspects 1 to 12.

[0036] According to the sheet member of Aspect 13, the possibility of separation between the skin side layer and the non-skin side layer can be reduced.

[0037] (Aspect 14) The non-skin side fibers are thermoplastic fibers. In the absorbent article, in the thickness direction, there is an adjacent member provided at a position overlapping with the sheet member. The absorbent article includes a welded joint portion where the sheet member and the adjacent member are welded and joined in the thickness direction. When the absorbent article is viewed in the thickness direction, a portion where the low basis weight portion and the non-skin side layer overlap has at least a part overlapping with the welded joint portion, and it is the sheet member of any one of Aspects 1 to 13.

[0038] According to the sheet member of Aspect 14, the possibility of a decrease in the joint strength of the welded joint portion can be reduced.

[0039] (Aspect 15) The non-skin-side fibers are thermoplastic fibers, and the absorbent article has a joined portion where both left and right sides in the lateral direction of a pair of waist-around portions are joined by welding. When viewed in the thickness direction, the sheet member is used at a position overlapping at least a part of the joined portion, and the joined portion overlaps at least a part of a portion where the low basis weight portion and the non-skin-side layer overlap. The sheet member is any one of aspects 1 to 14 characterized by this.

[0040] According to the sheet member of aspect 15, it is possible to reduce the risk of a decrease in the joining strength of the joined portions on both left and right sides in the lateral direction of a pair of waist-around portions.

[0041] (Aspect 16) The pair of waist-around portions have a plurality of joined portions intermittently in the vertical direction, and in the vertical direction, the distance between the centers of adjacent joined portions is longer than the distance between the centers of the low basis weight portions. The sheet member is of aspect 15 characterized by this.

[0042] According to the sheet member of aspect 16, while making it easier for the moisture absorbed by the skin-side layer to move from the low basis weight portion to the non-skin-side layer, it is possible to reduce the risk of a decrease in the joining strength of the joined portions on both left and right sides in the lateral direction of a pair of waist-around portions.

[0043] (Aspect 17) The joined portion is provided intermittently in the vertical direction. The sheet member has a longitudinal direction and a lateral direction orthogonal to the thickness direction, and the area of the region defined by a straight line connecting the centers of four adjacent low basis weight portions in the longitudinal direction and the lateral direction is smaller than the maximum area of the joined portion. The sheet member is of aspect 15 or 16 characterized by this.

[0044] According to the sheet member of aspect 17, compared to the case where the area of the region defined by a straight line connecting the centers of four adjacent low basis weight portions in the longitudinal direction and the lateral direction is made larger than the maximum area of the joined portion, it becomes easier to provide a wider region where the low basis weight portion and the joined portion overlap when viewed in the thickness direction, and it becomes easier to increase the joining strength at the joined portion.

[0045] (Aspect 18) The joint part is provided intermittently in the vertical direction. The sheet member has a longitudinal direction and a lateral direction orthogonal to the thickness direction, and the area of the region defined by the straight line connecting the centers of the four low basis weight portions adjacent to each other in the longitudinal direction and the lateral direction is larger than the minimum area of the joint part. The sheet member is according to Aspect 15 or 16.

[0046] According to the sheet member of Aspect 18, when the area of the region defined by the straight line connecting the centers of the four low basis weight portions adjacent to each other in the longitudinal direction and the lateral direction is made larger than the minimum area of the joint part, the region where the low basis weight portion and the joint part overlap when viewed in the thickness direction becomes wider, so that the bonding strength becomes excessively strong, and the possibility of making it difficult to separate the ventral body circumference part and the dorsal body circumference part after use of the absorbent article can be reduced.

[0047] (Aspect 19) An absorbent article having an absorber and a sheet member provided closer to the skin side than the absorber, wherein the sheet member has a skin-side layer capable of contacting the wearer's skin and a non-skin-side layer provided on the non-skin side of the skin-side layer, and the hydrophilicity of the skin-side fibers, which are the base fibers of the skin-side layer, is higher than the hydrophilicity of the non-skin-side fibers, which are the base fibers of the non-skin-side layer. The skin-side layer has a predetermined basis weight portion provided with the skin-side fibers of a predetermined basis weight and a low basis weight portion having a lower basis weight of the skin-side fibers than the predetermined basis weight portion. When viewed in the thickness direction, the absorbent article is characterized by having a portion where the predetermined basis weight portion overlaps with the non-skin-side layer and a portion where the low basis weight portion overlaps with the non-skin-side layer.

[0048] According to the absorbent article of Aspect 19, while improving the water absorption and the feel of the sheet member by the skin-side layer having high hydrophilicity, it becomes easier to move the moisture absorbed by the skin-side layer from the low basis weight portion to the non-skin side of the sheet member. Therefore, the possibility that the moisture absorbed by the sheet member continues to contact the wearer's skin can be reduced, and the discomfort and adverse effects on the wearer's skin can be reduced.

[0049] ===Embodiment=== Hereinafter, regarding the sheet member for the absorbent article according to the present embodiment, an adult pants-type disposable diaper 1 (hereinafter, also simply referred to as "diaper 1") will be taken as an example of the absorbent article and described. As an example of the sheet member, the sweat-absorbing sheets (sheet parts 25 and 35) of the waist-around parts 20 and 30 for diaper 1 will be taken as an example and described. However, the absorbent article according to the present embodiment is not limited to the above, and can also be applied, for example, as a pants-type disposable diaper for infants, a shorts-type napkin, a tape-type disposable diaper, etc. Further, as the sheet member, any member that can contact the skin side of each absorbent article may be used regardless of the sweat-absorbing sheet.

[0050] <Basic configuration of the pants-type disposable diaper 1> FIG. 1 is a schematic perspective view of diaper 1 seen from the ventral side. FIG. 2 is a schematic plan view of diaper 1 in a deployed and stretched state seen from the skin side of the wearer. FIG. 3 is a schematic cross-sectional view taken along line A-A in FIG. 2.

[0051] The "deployed state" of diaper 1 means that by releasing the joining of the side joining parts SS (described later) on both sides in the left-right direction of diaper 1 in the pants-type state of FIG. 1, the ventral waist-around part 20 (described later) and the dorsal waist-around part 30 (described later) are separated, and by opening diaper 1 in the vertical direction, diaper 1 is in a state of being deployed on a plane. Further, the "stretched state" of diaper 1 means a state in which the product (diaper 1) is stretched without wrinkles. Specifically, it means a state in which the dimensions of each member constituting diaper 1 (for example, the absorbent main body 10, the ventral waist-around part 20, etc.) are extended until they match or are close to the dimensions of the member alone.

[0052] Diaper 1 has a pant-like shape when worn as shown in Fig. 1, with vertical, horizontal, and front-back directions that intersect each other, and has a waist opening BH and a pair of leg openings LH. In the vertical direction, the side of the waist opening BH is the upper side, and the side that becomes the wearer's crotch is the lower side. In the front-back direction, the side that becomes the wearer's abdominal side is the front side, and the side that becomes the back side is the rear side. Also, in the unfolded and extended state shown in Fig. 2, diaper 1 has a longitudinal direction, a horizontal direction, and a thickness direction (the direction penetrating the paper surface in Fig. 2) as three mutually orthogonal directions. Note that the longitudinal direction is along the aforementioned vertical direction. One side of the longitudinal direction corresponds to the abdominal side (front side), and the other side corresponds to the back side (rear side). Also, diaper 1 has a thickness direction in which materials are laminated as shown in Fig. 3. The side that contacts the wearer in the thickness direction is the skin side, and the opposite side is the non-skin side.

[0053] Diaper 1 has an absorbent body 10 and an outer cover 18. The outer cover 18 has a pair of waist portions 20, 30 and a crotch portion 40 located at the wearer's crotch. The outer cover 18 is joined to the non-skin side surface of the absorbent body 10 with an adhesive or the like. Of the pair of waist portions 20, 30, the one located on the abdominal side (front side) of the wearer is also called the abdominal waist portion 20, and the one located on the back side (rear side) is also called the back waist portion 30. The abdominal waist portion 20 and the back waist portion 30 are joined by a pair of side joining portions SS on both sides in the horizontal direction. Examples of the joining method by the side joining portions SS include heat welding, ultrasonic welding, and a joining method using an adhesive.

[0054] As shown in FIG. 3, the absorbent body 10 has an absorbent core (absorbent) 11, a liquid-permeable topsheet 12 disposed closer to the skin side than the absorbent core 11, a liquid-impermeable backsheet 13 disposed closer to the non-skin side than the absorbent core 11, and an outer wrapper sheet 14. The absorbent core 11 may be any material that can absorb and hold excreted fluids. Examples include those formed by shaping liquid-absorbent materials such as pulp fibers and superabsorbent polymers (SAP) into a predetermined shape. Further, the absorbent core 11 may be covered with a liquid-permeable sheet such as tissue paper or non-woven fabric. The topsheet 12 is formed of, for example, a non-woven fabric such as an air-through non-woven fabric or a spunbond non-woven fabric. The backsheet 13 is, for example, a liquid-impermeable and breathable film such as polyethylene or polypropylene. The outer wrapper sheet 14 is formed of, for example, a non-woven fabric equivalent to the topsheet 12.

[0055] As shown in FIG. 2, on both sides of the absorbent body 10 in the left-right direction, a plurality of elastic members 15 (e.g., thread rubber) that stretch along the longitudinal direction of the absorbent body 10 are provided around the legs. Further, an anti-leakage wall portion that can stand up on the skin side may be provided by, for example, providing an elastic member that stretches in the longitudinal direction inside the elastic members 15 around the legs in the left-right direction.

[0056] As shown in FIGS. 2 and 3, the outer package 18 has an inner layer sheet 21, a ventral outer layer sheet 22 (outer layer sheet), and a dorsal outer layer sheet 32 (outer layer sheet).

[0057] The inner layer sheet 21 is disposed from the ventral body circumference portion 20 through the crotch portion 40 to the dorsal body circumference portion 30 (FIG. 3). The width (length in the left-right direction) of the inner layer sheet 21 at the ventral body circumference portion 20 and the dorsal body circumference portion 30 is larger than the width (length in the left-right direction) of the inner layer sheet 21 at the crotch portion 40 (FIG. 2). As the inner layer sheet 21, an air-through non-woven fabric, a spunbond non-woven fabric, an SMS non-woven fabric (spunbond-meltblown-spunbond non-woven fabric), a waterproof film, etc. can be used.

[0058] As shown in FIGS. 2 and 3, the ventral outer layer sheet 22 is provided on the non-skin side of the inner layer sheet 21, and the ventral outer layer sheet 22 and the inner layer sheet 21 constitute the ventral body circumferential portion 20. The outer end (upper end) of the ventral outer layer sheet 22 in the longitudinal direction is folded back to the skin side. The folded portion 22r of the ventral outer layer sheet 22 wraps around one end (outer end) of the inner layer sheet 21 in the longitudinal direction. Note that the outer end (upper end) of the ventral outer layer sheet 22 in the longitudinal direction may not be folded back.

[0059] Similarly, as shown in FIGS. 2 and 3, the dorsal outer layer sheet 32 is provided on the non-skin side of the inner layer sheet 21, and the dorsal outer layer sheet 32 and the inner layer sheet 21 constitute the dorsal body circumferential portion 30. The outer end (upper end) of the dorsal outer layer sheet 32 in the longitudinal direction is folded back to the skin side. The folded portion 32r of the dorsal outer layer sheet 32 wraps around the other end (outer end) of the inner layer sheet 21 in the longitudinal direction. Note that the outer end (upper end) of the dorsal outer layer sheet 32 in the longitudinal direction may not be folded back.

[0060] As the ventral outer layer sheet 22 and the dorsal outer layer sheet 32, an air-through nonwoven fabric, a spunbond nonwoven fabric, an SMS nonwoven fabric (spunbond-meltblown-spunbond nonwoven fabric), etc. can be used.

[0061] The ventral body circumferential portion 20 and the dorsal body circumferential portion 30 each have body circumferential elastic members 23 and 33 that can expand and contract in the left-right direction. The plurality of body circumferential elastic members 23 and 33 are arranged at intervals in the up-down direction between the inner layer sheet 21 and the ventral outer layer sheet 22 and between the inner layer sheet 21 and the dorsal outer layer sheet 32, and are fixed in an extended state in the left-right direction (see FIGS. 2 and 3). Therefore, the ventral body circumferential portion 20 and the dorsal body circumferential portion 30 expand and contract in the left-right direction and fit the wearer's body circumference. Note that examples of the body circumferential elastic members 23 and 33 include thread-like elastic members such as thread rubber and elongated elastic sheets.

[0062] In addition, in the present embodiment, in the dorsal trunk portion 30, the hind-leg-around elastic member 34 is provided between the inner layer sheet 21 and the dorsal outer layer sheet 32. The hind-leg-around elastic member 34 may be, for example, a plurality of thread rubbers, an elastic sheet in the form of a stretchable band, or the like. The hind-leg-around elastic member 34 is joined and fixed by an adhesive such as a hot melt adhesive in an extended state.

[0063] In addition, in the present embodiment, in a predetermined region on the outermost skin side of the ventral trunk portion 20 and the dorsal trunk portion 30, sheet portions 25 and 35 that are likely to absorb the sweat of the wearer are provided (the hatched portions in FIG. 2). The sheet portions 25 and 35 are disposed closer to the skin side than the absorbent body 10 (absorbent core 11), are shorter in the vertical direction than the inner layer sheet 21, the ventral and dorsal outer layer sheets 22 and 32, etc., and are strip-shaped sheet members disposed so as to cover the longitudinal end portions of the absorbent body 10. Details of the sheet portions 25 and 35 will be described later.

[0064] The basic configuration of the diaper 1 has been described above, but the configuration of the diaper 1 described above is merely an example and is not limited thereto. For example, in the diaper 1 of the present embodiment, the outer package 18 having three parts, namely, the ventral trunk portion 20, the dorsal trunk portion 30, and the crotch portion 40 connecting them, is provided. However, the present invention is not limited to this. For example, the ventral trunk portion 20 and the dorsal trunk portion 30 may be formed of separate members, and the diaper may have a configuration in which the non-skin side surface of the absorbent body 10 is exposed in the crotch portion, or the diaper may have an outer package member formed of a single member continuous from the ventral trunk portion 20 to the dorsal trunk portion 30.

[0065] <Regarding the sheet portions 25 and 35> Hereinafter, the specific configurations of the sheet portions 25 and 35 according to the present embodiment will be described. In the present embodiment, the sheet portion 25 provided in the ventral body circumferential portion 20 and the sheet portion 35 provided in the dorsal body circumferential portion 30 have substantially the same configuration. Therefore, in the following description, for the content common to both the sheet portion 25 and the sheet portion 35, only the sheet portion 25 will be described on behalf of both. For the sheet portion 35, specific descriptions will be omitted, such as indicating the reference numerals of the members corresponding to the sheet portion 25 in parentheses as necessary.

[0066] FIG. 4 is a schematic cross-sectional view of the sheet portion 25. FIG. 5A is a diagram for explaining the state of the sheet portion 25 viewed from the skin side. FIG. 5B is an enlarged schematic view of a part of FIG. 4A. As described above, in the present embodiment, the sheet portion 25 constitutes a part of the surface that contacts the skin of the wearer in the ventral body circumferential portion 20 (FIG. 3). And as shown in FIG. 4, the sheet portion 25 has a skin-side layer 25a arranged to contact the skin of the wearer and a non-skin-side layer 25b located on the non-skin side in the thickness direction of the skin-side layer 25a.

[0067] The skin-side layer 25a is a layer having cotton fibers, which are hydrophilic fibers, as base fibers. Note that the above-mentioned "base material" means a material whose mass ratio in each layer (skin-side layer 25a, non-skin-side layer 25b) exceeds 50%. As the non-skin-side fibers, which are the base fibers of the non-skin-side layer 25b, polyester fibers, polypropylene fibers, polyethylene fibers, polyurethane fibers, and composite fibers thereof can be used. However, any of the above-mentioned fibers may be used, whether they are those with a hydrophilic treatment on the fiber surface or those without a hydrophilic treatment. Hereinafter, the base fibers of the skin-side layer 25a will also be referred to as "skin-side fibers", and the base fibers of the non-skin-side layer 25b will also be referred to as "non-skin-side fibers".

[0068] In addition, in the sheet member constituting the sheet portion 25 of the present embodiment, the skin-side fibers (cotton fibers) 25as, which are the base fibers of the skin-side layer 25a, are entangled with the non-skin-side fibers 25bs, which are the base fibers of the non-skin-side layer 25b (FIG. 4). As a method of integrating the skin-side layer 25a and the non-skin-side layer 25b by entanglement, for example, a known water jet entanglement method or the like can be used.

[0069] Although the non-skin-side fibers 25bs of the non-skin-side layer 25b of the present embodiment are hydrophobic fibers, those obtained by previously applying a hydrophilizing agent to the non-skin-side fibers 25bs are entangled with the skin-side fibers 25as using the water jet entanglement method to form a sheet. In the process of this entanglement, the hydrophilizing agent applied to the surface of the base fibers of the non-skin-side layer 25b is partially removed by the water flow. Therefore, the non-skin-side fibers 25bs of the non-skin-side layer 25b in the present embodiment include fibers in which the hydrophilizing agent has been completely removed to become hydrophobic fibers, fibers in which a part of the hydrophilizing agent has been removed but the hydrophilizing agent remains partially, and fibers in which the hydrophilizing agent remains completely.

[0070] The sheet portion 25 can be provided on the skin side surface of the diaper 1, and the thickness direction of the sheet portion 25 follows the thickness direction of the diaper 1. The longitudinal direction and the lateral direction of the sheet portion 25 may or may not follow the vertical direction and the horizontal direction of the diaper 1, respectively. If the plane of the sheet portion 25 and the plane of the diaper 1 are along each other, the sheet portion 25 can be used in any direction.

[0071] Since the sheet portion 25 is a member that comes into contact with the skin of the wearer during wearing, it is preferably soft to the touch. Therefore, it is preferable that the member constituting the sheet portion 25 is a fiber with a good touch. As fibers with a good touch, for example, hydrophilic fibers such as cotton and rayon are known. On the other hand, the higher the hydrophilicity of the fiber, the easier it is for the fiber itself to absorb moisture and the easier it is to continuously hold the absorbed moisture. Therefore, there is a risk that the diaper 1 becomes stuffy due to the sheet portion 25, moisture continuously adheres to the skin of the wearer, causing discomfort to the skin of the wearer, or having an adverse effect such as rough skin.

[0072] On the other hand, the sheet portion 25 that can contact the wearer's skin and is used for the diaper 1 has a skin-side layer 25a and a non-skin-side layer 25b provided on the non-skin side of the skin-side layer 25a. And the hydrophilicity of the skin-side fibers 25as of the skin-side layer 25a is higher than that of the non-skin-side fibers 25bs of the non-skin-side layer 25b. Further, the skin-side layer 25a has a predetermined basis weight portion 25aP provided with skin-side fibers 25as of a predetermined basis weight and a low basis weight portion 25aL where the basis weight of the skin-side fibers 25as is lower than that of the predetermined basis weight portion 25aP. And as shown in FIGS. 4 and 5, when the sheet portion 25 (diaper 1) is viewed in the thickness direction, there are a portion where the predetermined basis weight portion 25aP and the non-skin-side layer 25b overlap and a portion where the low basis weight portion 25aL overlaps.

[0073] As described above, the fibers in the sheet portion 25 tend to have improved water absorption and texture as the hydrophilicity of the fibers increases. In particular, hydrophilic fibers such as cotton fibers and rayon fibers are fibers with high hydrophilicity that are soft and have a rounded fiber shape, resulting in less irritation to the skin and a good feel on the skin. Therefore, the skin-side layer 25a provided with the skin-side fibers 25as having a high hydrophilicity is provided closer to the skin side than the non-skin-side layer 25b having a lower hydrophilicity than the skin-side fibers 25as. When the sheet portion 25 is viewed in the thickness direction, the predetermined basis weight portion 25aP of the skin-side layer 25a and the non-skin-side layer 25b overlap, so that during wearing, the predetermined basis weight portion 25aP in the sheet portion 25 comes into contact with the skin of the wearer, improving the water absorption and texture of the sheet portion 25 (diaper 1) during wearing. On the other hand, the sheet portion 25 has a low basis weight portion 25aL with a low basis weight of the skin-side fibers. When the sheet portion 25 is viewed in the thickness direction, the low basis weight portion 25aL and the non-skin-side layer 25b overlap, so that during wearing, the portion where the predetermined basis weight portion 25aP and the non-skin-side layer 25b overlap when viewed in the thickness direction absorbs moisture such as sweat from the skin of the wearer, making it easier for the moisture absorbed by the predetermined basis weight portion 25aP to evaporate from the low basis weight portion 25aL with a low basis weight of the skin-side fibers 25as or facilitating the movement of moisture from the low basis weight portion 25aL to the non-skin-side layer 25b. Also, even when the skin-side layer 25a absorbs moisture such as sweat during wearing, the portion of the skin-side layer 25a that comes into contact with the skin of the wearer can be made smaller, so that even when the skin-side fibers 25as of the skin-side layer 25a absorb moisture, the risk of making the wearer feel sticky on the skin can be reduced. Therefore, the risk of the skin-side layer 25a continuously retaining excessive moisture can be reduced, and the risk of the diaper 1 becoming stuffy or having an adverse effect such as skin roughness on the wearer can be reduced. As a result, by the diaper 1 having such a sheet portion 25, the discomfort and adverse effects on the skin of the wearer of the diaper 1 can be reduced.

[0074] The "low basis weight part 25aL" may be a part where the basis weight of the skin-side fibers 25as is lower than that of the predetermined basis weight part 25aP, including the case where the skin-side fibers 25as are provided in the low basis weight part 25aL and the case where the skin-side fibers 25as are not provided. In any case, it is preferable that the low basis weight part 25aL is a part recessed on the non-skin side compared to the predetermined basis weight part 25aP. Since the low basis weight part 25aL is recessed on the non-skin side compared to the predetermined basis weight part 25aP, when worn, among the skin-side layers 25a of the sheet part 25, the predetermined basis weight part 25aP becomes a part that easily contacts the wearer's skin, improving the skin contact with the wearer while the low basis weight part 25aL becomes a part that hardly contacts the wearer's skin. Therefore, it becomes easier to move moisture such as sweat and humidity to the non-skin side layer 25b through the low basis weight part 25aL with few skin-side fibers 25as, or even when the skin-side layer 25a absorbs moisture such as sweat during wearing, the part of the skin-side layer 25a that contacts the wearer's skin is reduced, and even when the skin-side fibers 25as of the skin-side layer 25a absorb moisture, the fear of making the wearer feel sticky on the skin can be reduced.

[0075] The low basis weight part 25aL of the present embodiment is a part where almost no skin-side fibers 25as are provided, and there is a part where the basis weight of the skin-side fibers 25as is 0 (zero). Plainly speaking, it is a part where the skin-side layer 25a is missing in the thickness direction. Therefore, when the sheet part 25 is viewed from the skin side, the non-skin side layer 25b (non-skin side fibers 25bs) can be visually recognized through the low basis weight part 25aL. Since the skin-side fibers 25as are soft fibers and have some fluidity, the part where the basis weight of the skin-side fibers 25as is 0 (zero) does not mean that the skin-side fibers 25as are completely absent (zero), and it may be a part where several skin-side fibers 25as are provided in the low basis weight part 25aL.

[0076] With respect to the skin-side layer 25a, it is preferable that the non-skin-side layer 25b is provided over substantially the entire area of the sheet portion 25 when viewed in the thickness direction of the sheet portion 25. Therefore, when the basis weight of the skin-side fibers 25as is 0 (zero), the portion where the low-basis-weight portion 25aL and the non-skin-side layer 25b overlap is not blocked by the skin-side fibers 25as when viewed from the skin side, so that the non-skin-side layer 25b can be directly visually recognized. Since the non-skin-side layer 25b is formed by entanglement of fibers such as non-skin-side fibers 25bs, there are gaps between the fibers. Since these gaps between the fibers are extremely small, it can be said that the non-skin-side layer 25b is provided over the entire area of the sheet portion 25. That is, the non-skin-side layer 25b is a layer that does not have openings such as intentionally provided through holes.

[0077] As in the present embodiment, when the basis weight of the skin-side fibers 25as in the low-basis-weight portion 25aL is 0 (zero), during wearing, among the skin-side layers 25a of the sheet portion 25, the predetermined-basis-weight portion 25aP is likely to come into contact with the skin of the wearer, and the low-basis-weight portion 25aL is less likely to come into contact with the skin of the wearer. Therefore, in the low-basis-weight portion 25aL, moisture such as sweat is less likely to be retained by the skin-side fibers 25as and is more likely to be absorbed by the non-skin-side layer 25b. As a result, while improving the skin contact with the wearer by the contact of the predetermined-basis-weight portion 25aP with the skin of the wearer, it becomes easier to promote the absorption of moisture by the non-skin-side layer 25b, so that it becomes easier to reduce the risk of continuously retaining moisture in the skin-side layer 25a.

[0078] The "hydrophilicity" of the above-described fibers is evaluated based on the contact angle of the fibers measured by the following method. Specifically, the smaller the measured contact angle, the higher the hydrophilicity, and the larger the contact angle, the lower the hydrophilicity.

[0079] <Method for Measuring Contact Angle> (1) First, cotton fibers and non-skin-side fibers are taken out from predetermined portions of each layer. The taken-out fibers are cut to a fiber length of 10 mm, and five fibers of each are prepared as samples. (2) As the measuring device, an automatic minimum contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used, and the measuring environment is a room temperature of 22 ± 2°C and a humidity of 65 ± 2%RH. (3) Place the sample on the measuring device, drop 20 picoliters of distilled water (micro-droplets) from the inkjet head mounted on the device onto the surface of the fiber, and record the state of the micro-droplets over time. (4) Analyze the image immediately after the micro-droplets adhere to the surface of the fiber, and calculate the contact angle of the micro-droplets with respect to the fiber surface. (5) Measure the contact angles at 20 different locations for each fiber. Measure the contact angles of 5 samples respectively, and adopt the average value of the 100 measured values in total as the contact angle. In addition, when the layer (sheet) to be measured is joined to other members by an adhesive, fusion, etc., weaken the adhesive force with a cooling means such as cold spray within a range that does not affect the contact angle of the fiber, and then take it out.

[0080] In the sheet portion 25, it is preferable to have a portion where the skin-side fibers 25as and the non-skin-side fibers 25bs are intertwined. By forming the sheet portion 25 by the intertwining of the fibers, the flexibility of the sheet portion 25 can be improved, and the touch of the diaper 1 using this sheet 25 can be improved. The intertwining of the skin-side fibers 25as and the non-skin-side fibers 25bs can be performed by a well-known method such as a water flow or air.

[0081] Also, it is preferable that no adhesive is provided on the sheet portion 25. By the sheet portion 25 not having an adhesive, the possibility of the sheet portion 25 becoming hard can be reduced, and the possibility of the touch of the diaper 1 using the sheet portion 25 decreasing can be reduced. Also, the possibility of the absorption of moisture being hindered by the adhesive can be reduced, and the possibility of moisture such as sweat remaining on the surface of the sheet portion 25 can be reduced, and the possibility of giving discomfort or adverse effects to the skin of the wearer can be reduced. Although it is preferable that no adhesive is provided on the sheet portion 25 itself, an adhesive may be used to fix the sheet portion 25 to a member adjacent to the sheet portion 25 in the diaper 1. The sheet portion 25 may be fixed at a predetermined position of the diaper 1 using an adhesive, and the adhesive used for this fixing may impregnate the sheet portion 25.

[0082] Similarly, it is preferable that the sheet portion 25 is not provided with a portion where a part of the sheet portion 25 is squeezed in the thickness direction. By the squeezed portion provided in the sheet portion 25, it is possible to reduce the risk of the sheet portion 25 becoming hard and reduce the risk of the texture of the diaper 1 using the sheet portion 25 deteriorating. Note that the "portion squeezed in the thickness direction" of the sheet portion 25 is a portion where the sheet portion 25 is locally squeezed, and does not include a case where pressure is applied over the entire area of the sheet portion 25 during the formation of the sheet portion 25.

[0083] Regarding the skin-side fibers 25as in the skin-side layer 25a of the sheet portion 25, it is preferable that the skin-side fibers 25as are cotton fibers. Cotton fibers are soft, have a rounded fiber shape, and have high water absorbency. Therefore, by making the skin-side fibers 25as of the skin-side layer 25a that contacts the skin of the wearer cotton fibers, the skin feel on the wearer is good, and the irritation to the skin of the wearer during wearing can be reduced.

[0084] As the fibers forming the skin-side layer 25a, the weight ratio of the skin-side fibers 25as, which are the base fibers, may be greater than 50%, and fibers other than the skin-side fibers 25as (for example, hydrophobic fibers) may be included. Further, examples of the skin-side fibers 25as include cellulose-based fibers such as cotton and rayon, and thermoplastic resin fibers subjected to a hydrophilization treatment. The skin-side fibers 25as, which are the base fibers of the skin-side layer 25a, may be only one type of fiber or a plurality of fibers. In the skin-side layer 25a of the present embodiment, the skin-side fibers 25as are 100% cotton fibers, and the skin-side layer 25a is formed almost entirely of cotton fibers (skin-side fibers 25as).

[0085] Note that, since the sheet portion 25 is formed into a sheet shape by the entanglement of the fibers of the skin-side layer 25a (skin-side fibers 25as) and the fibers of the non-skin-side layer 25b (non-skin-side fibers 25bs), at least a part of the fibers of the non-skin-side layer 25b (non-skin-side fibers 25bs) is arranged in the skin-side layer 25a. And it is preferable that at least a part of the skin-side fibers 25as exists on the non-skin side surface of the non-skin-side layer 25b. Thereby, the entanglement between the skin-side layer 25a and the non-skin-side layer 25b can be made stronger, and the possibility of the separation between the skin-side layer 25a and the non-skin-side layer 25b can be reduced.

[0086] As the fibers forming the non-skin-side layer 25b, the weight ratio of the non-skin-side fibers 25bs which are the base fibers only needs to be greater than 50%, and fibers other than the non-skin-side fibers 25bs (for example, hydrophilic fibers) may be included. Further, examples of the non-skin-side fibers 25bs include thermoplastic resin fibers and the like. The non-skin-side fibers 25bs which are the base fibers of the non-skin-side layer 25b may be only one kind of fiber, or may be a plurality of fibers. In the non-skin-side layer 25b of the present embodiment, the non-skin-side fibers 25bs are 100% of the composite fibers having a sheath-core structure of polypropylene (PP) and polyethylene (PE), and the non-skin-side layer 25b is formed substantially only of the composite fibers (non-skin-side fibers 25bs) of PP and PE. Note that, since the sheet portion 25 is formed into a sheet shape by the entanglement of the fibers of the skin-side layer 25a (skin-side fibers 25as) and the fibers of the non-skin-side layer 25b (non-skin-side fibers 25bs), at least a part of the fibers of the skin-side layer 25a (skin-side fibers 25as) is arranged in the non-skin-side layer 25b.

[0087] In addition to the basis weight of the skin-side fibers 25as in the low basis weight portion 25aL being lower than the basis weight of the skin-side fibers 25as in the predetermined basis weight portion 25aP in the skin-side layer 25a of the sheet portion 25, it is more preferable that not only the skin-side fibers 25as but also the basis weight of all the fibers existing in the low basis weight portion 25aL of the skin-side layer 25a is lower than the basis weight of all the fibers existing in the predetermined basis weight portion 25aP.

[0088] Further, it is preferable that at least a part of the non-skin-side fibers 25bs is present on the skin side surface of the skin side layer 25a. Since the non-skin-side fibers 25bs have lower liquid retention than the skin side fibers 25as, the non-skin-side fibers 25bs present on the skin side surface of the skin side layer 25a are more likely to move moisture toward the non-skin side layer 25b than the non-skin-side fibers 25bs themselves absorb moisture such as sweat. Therefore, it is possible to reduce the risk that the moisture absorbed by the sheet portion 25 continues to contact the wearer's skin, and it is possible to reduce discomfort and adverse effects on the wearer's skin.

[0089] As described above, in the skin side sheet 25, since the skin side fibers 25as of the skin side layer 25a and the non-skin side fibers 25bs of the non-skin side layer 25b are formed into a sheet shape by entanglement, the skin side fibers 25as and the non-skin side fibers 25bs have fibers entangled with each other. Therefore, in the skin side layer 25a, in the predetermined basis weight portion 25aP, the number of non-skin side fibers 25bs entangled with the skin side fibers 25as is preferably larger than the number of non-skin side fibers 25bs entangled with the skin side fibers 25as in the low basis weight portion 25aL. Thereby, it becomes easier to promote the movement of moisture from the skin side surface to the non-skin side surface of the predetermined basis weight portion 25aP by the non-skin side fibers 25bs located in the predetermined basis weight portion 25aP. Therefore, it is possible to reduce the risk that the moisture absorbed by the sheet portion 25 continues to contact the wearer's skin, and it is possible to reduce discomfort and adverse effects on the wearer's skin.

[0090] In the sheet portion 25, it is preferable that the density of the skin side fibers 25as in the low basis weight portion 25aL is lower than the density of the skin side fibers 25as in the predetermined basis weight portion 25aP. When worn, the portion where the predetermined basis weight portion 25aP and the non-skin side layer 25b overlap in the thickness direction absorbs moisture such as sweat from the wearer's skin, and promotes the evaporation of the moisture absorbed by the predetermined basis weight portion 25aP from the low basis weight portion 25aL where the basis weight of the skin side fibers 25as is low, or makes it easier to promote the movement of moisture from the low basis weight portion 25aL to the non-skin side layer 25b. Therefore, it is possible to reduce the risk of excessive moisture retention in the skin side layer 25a, and to reduce the risk of the diaper 1 becoming stuffy or causing adverse effects such as skin roughness. And it is possible to reduce discomfort and adverse effects on the skin of the wearer of the diaper 1.

[0091] As shown in FIGS. 5A and 5B, in the sheet portion 25, in the vertical direction, a predetermined basis weight portion 25aP and a low basis weight portion 25aL are alternately arranged, and in the left - right direction, it is preferable that the predetermined basis weight portion 25aP and the low basis weight portion 25aL are alternately arranged. In the disposable diaper 1 of the present embodiment, the vertical direction of the disposable diaper 1 is along the longitudinal direction of the sheet portion 25, and the left - right direction of the disposable diaper 1 is along the lateral direction of the sheet portion 25. And, in the sheet portion 25, the non - skin - side layer 25b is provided over the entire vertical and horizontal directions, and the skin - side layer 25a is provided in a chevron pattern on the skin - side of the non - skin - side layer 25b. Thereby, when worn, the portion where the predetermined basis weight portion 25aP and the non - skin - side layer 25b overlap in the thickness direction absorbs moisture such as sweat of the wearer's skin, and the moisture absorbed by the predetermined basis weight portion 25aP is more likely to evaporate from the low basis weight portion 25aL where the basis weight of the skin - side fibers 25as is low, and it is easier to promote the movement of moisture from the low basis weight portion 25aL to the non - skin - side layer 25b. Therefore, it is possible to reduce the risk of continuously retaining excessive moisture in the skin - side layer 25a, and to reduce the risk of the disposable diaper 1 becoming stuffy or causing adverse effects such as skin roughness. And, by alternately arranging the predetermined basis weight portion 25aP and the low basis weight portion 25aL in the vertical direction and alternately arranging the predetermined basis weight portion 25aP and the low basis weight portion 25aL in the left - right direction, it is possible to reduce the discomfort and adverse effects on the skin of the wearer of the disposable diaper 1 in a wide range in the sheet portion 25. Note that the arrangement of the predetermined basis weight portion 25aP and the low basis weight portion 25aL in the sheet portion 25 is not limited to this. In the vertical direction, as long as the predetermined basis weight portion 25aP and the low basis weight portion 25aL are alternately arranged, and in the left - right direction, as long as the predetermined basis weight portion 25aP and the low basis weight portion 25aL are alternately arranged, for example, they may be arranged in a grid pattern or randomly arranged.

[0092] In the above - described embodiment, the skin - side layer 25a and the non - skin - side layer 25b are integrated by entangling the skin - side fibers 25as and the non - skin - side fibers 25bs of the sheet portion 25, but it is not limited to this. For example, the sheet portion 25 may have a sheet pressing portion (not shown) in which a part of the skin - side layer 25a and the non - skin - side layer 25b is pressed in the thickness direction. That is, the sheet portion 25 itself may be pressed. Thereby, the risk of the skin - side layer 25a and the non - skin - side layer 25b separating can be reduced.

[0093] Further, it may have a portion where only the skin-side layer 25a or only the non-skin-side layer 25b is squeezed. For example, in the manufacturing process of the sheet portion 25, after forming into a layer by squeezing the non-skin-side fibers 25bs in the thickness direction, the non-skin-side fibers 25bs and the skin-side fibers 25as may be intertwined to form the sheet portion 25.

[0094] Further, the sheet portion 25 may have a portion (not shown) where the skin-side fibers 25as of the skin-side layer 25a and the non-skin-side fibers 25bs of the non-skin-side layer 25b are melt-bonded. That is, the sheet portion 25 may have a portion where the sheet portion 25 itself is melted. Thereby, the possibility of separation between the skin-side layer 25a and the non-skin-side layer 25b can be reduced.

[0095] Regarding the sheet portion 25, after intertwining the skin-side fibers 25as and the non-skin-side fibers 25bs, it may further include a sheet squeezing portion or a portion where the skin-side fibers 25as and the non-skin-side fibers 25bs are melt-bonded.

[0096] Also, it is preferable that the diaper 1 has a hydrophilic member provided with fibers having a higher hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet portion 25. In the diaper 1, it is more preferable that the sheet portion 25 is used on the skin side in the thickness direction from the hydrophilic member and at a position overlapping the hydrophilic member when the diaper 1 is viewed in the thickness direction. Specifically, in the present embodiment, as shown in FIG. 3, the diaper 1 includes a topsheet 12 provided with fibers having a higher hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet portion 25, and the topsheet 12 corresponds to the hydrophilic member. The fibers of the topsheet 12 or the topsheet 2 itself are subjected to a hydrophilic treatment by a well-known method, so that the fibers of the topsheet 12 have a higher hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet portion 25. And in the diaper 1, the sheet portion 25 is used on the skin side from the topsheet 12 and at a position overlapping the topsheet when the diaper 1 is viewed in the thickness direction. Thereby, when the diaper 1 is worn, it becomes easier to move moisture such as sweat absorbed from the sheet portion 25 side to the non-skin side, so that it is possible to reduce the discomfort caused by the continuous adhesion of moisture to the skin of the wearer and the adverse effects on the skin of the wearer. Note that the hydrophilic member in the diaper 1 is not limited to the topsheet 12, and any member may be used as long as it is provided with fibers having a higher hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet portion 25 and overlaps the sheet portion 25 when viewed in the thickness direction. For example, the absorber 11, the inner layer sheet 21, etc. may be the hydrophilic member. Regarding the comparison of the hydrophilicity of the non-skin-side fibers 25bs and the fibers of the topsheet 12, the above-described method for measuring hydrophilicity can be used.

[0097] On one hand, the diaper 1 has a non-hydrophilic member including fibers with a lower hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet portion 25. In the diaper 1, the sheet portion 25 may be provided on the skin side in the thickness direction from this non-hydrophilic member and at a position overlapping the non-hydrophilic member when the diaper 1 is viewed in the thickness direction. For example, in the diaper 1, the topsheet 12 provided on the non-skin side from the non-skin-side layer 25bs may include fibers with a lower hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b and may be provided at a position overlapping the sheet portion 25 when viewed in the thickness direction. Although the topsheet 12 of the present embodiment is subjected to a hydrophilic treatment, the topsheet 12 as a non-hydrophilic member may be provided with fibers having a low hydrophilicity without being subjected to a hydrophilic treatment. By providing the non-hydrophilic member on the non-skin side from the non-skin-side layer 25b, when the diaper 1 is worn, the moisture absorbed by the sheet portion 25 is suppressed from migrating from the non-skin-side layer 25b toward the non-hydrophilic member, and it becomes easier to retain moisture in the non-skin-side layer 25b. Therefore, it is possible to reduce the risk that the moisture absorbed from the sheet portion 25 side penetrates to the non-skin side of the diaper 1 and makes the non-skin side surface of the diaper 1 sticky. Further, since the basis weight of the skin-side fibers 25as of the low-basis-weight portion 25aL is low, the thickness of the low-basis-weight portion 25aL is thinner than that of the predetermined-basis-weight portion 25aP, and it is more likely to be recessed on the non-skin side than the predetermined-basis-weight portion 25aP. Therefore, in the portion overlapping the low-basis-weight portion 25aL when viewed in the thickness direction, it is possible to reduce the risk that moisture continues to adhere to the skin of the wearer. Therefore, it is possible to reduce the discomfort on both the skin side and the non-skin side of the diaper 1 when worn.

[0098] In addition, the diaper 1 has an expandable and contractible member. In the diaper 1 in the deployed and extended state, it is preferable that a sheet portion 25 is provided at a position overlapping at least a part of the expandable and contractible member when viewed in the thickness direction. In the diaper 1 of the present embodiment, as shown in FIG. 3, it has a waist elastic member 23 that can expand and contract in the left-right direction. In the diaper 1 in the deployed and extended state, the sheet portion 25 is used at a position overlapping at least a part of the waist elastic member 23 when viewed in the thickness direction. By the contraction of the waist elastic member 23, wrinkles can be formed in the ventral waist portion 20 and the sheet portion 25. Therefore, while improving the texture of the diaper 1 by the sheet portion 25, the breathability of the sheet portion 25 can be improved by the wrinkles formed in at least a part of the sheet portion 25, and the stuffiness when wearing the diaper 1 and the irritation to the wearer's skin can be reduced.

[0099] As described above, the ventral waist portion 20 and the dorsal waist portion 30 are joined by a pair of side joining portions (joining portions) SS on both sides in the left-right direction. FIG. 6 is an enlarged schematic view of a portion X in FIG. 2. In the present embodiment, since the inner layer sheet 21 and the ventral outer layer sheet 22 of the ventral waist portion 20 are formed of a non-woven fabric made of thermoplastic resin fibers, the side joining portion SS is composed of a plurality of joining portions 70 joined by welding. In FIG. 6, the joining portion 70 is indicated by a left-diagonal downward hatched portion. In such a case, it is preferable that the non-skin-side fibers 25bs of the sheet portion 25 are thermoplastic fibers. Then, as shown in FIGS. 2 and 6, etc., when the diaper 1 (sheet portion 25) is viewed in the thickness direction, the sheet portion 25 is provided at a position overlapping at least a part of the side joining portion SS, and the side joining portion SS preferably overlaps at least a part of the portion overlapping the low basis weight portion 25aL and the non-skin-side layer 25b. Thereby, the possibility of a decrease in the joining strength of the side joining portion SS on both sides in the left-right direction of the pair of waist portions 20 and 30 can be reduced.

[0100] Specifically, in the pant-type state, the side joint SS is stacked in the front-to-back direction from the front side to the back side in the order of the ventral outer layer sheet 22, the inner layer sheet 21, (the folded portion 22r, the folded portion 32r,) the inner layer sheet 21, and the dorsal outer layer sheet 32, and a welded joint 70 is formed by applying ultrasonic waves, pressure, heat, etc. (see FIGS. 2 and 3). In the diaper 1, sheet portions 25 and 35 are provided on the innermost side of the body circumferential portions 20 and 30 and closer to the skin side than the absorbent main body 10 (absorbent body 11). The sheet portions 25 and 35 are provided between the inner layer sheet 21 of the ventral body circumferential portion 20 and the inner layer sheet 21 of the dorsal body circumferential portion 30. The sheet portions 25 and 35 are overlapped with the ventral outer layer sheet 22, the inner layer sheet 21 of the ventral body circumferential portion 20, the inner layer sheet 21 of the dorsal body circumferential portion 30, and the dorsal outer layer sheet 32, and a welded joint 70 is formed by welding in a state where all these sheets overlap in the thickness direction, thereby forming the side joint SS.

[0101] The skin-side layer 25a of the sheet portion 25 is preferably formed of fibers with high hydrophilicity such as cotton fibers and rayon fibers as the skin-side fibers 25as. However, since such fibers are difficult to melt even when ultrasonic waves, heat, etc. are applied, they tend to hinder the welding joint and may reduce the joint strength of the side joint portion SS. However, in the sheet portion 25 of the present embodiment, even if the sheet portion 25 is provided at a position overlapping the side joint portion SS when viewed in the thickness direction, the sheet portion 25 has a predetermined basis weight portion 25aP and a low basis weight portion 25aL. When viewed in the thickness direction of the diaper 1, the side joint portion SS overlaps at least a part of the portion where the low basis weight portion 25aL overlaps the non-skin-side layer 25b. As a result, in the low basis weight portion 25aL, it is a portion where the amount of the skin-side fibers 25as is small, and the thermoplastic fibers, which are the non-skin-side fibers 25bs of the non-skin-side layer 25b, are easily melted with the fibers of the inner sheet 21 or the like, thereby reducing the possibility of hindering the fusion bonding due to the provision of the sheet portion 25 and reducing the decrease in the joint strength of the side joint portion SS. In particular, in the present embodiment, since the basis weight of the skin-side fibers 25as in the low basis weight portion 25aL is 0 (zero), in the low basis weight portion 25aL, the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet portion 25 and the inner sheet 21 or the like can be fusion-bonded without the skin-side fibers 25as in between. Thereby, the possibility of the joint strength of the side joint portion SS decreasing can be further reduced.

[0102] Furthermore, as shown in FIG. 6, when there are a plurality of joints 70 intermittently in the vertical direction at the side joint SS of the pair of waist portions of the diaper 1, it is preferable that the distance L70 between the centers 70c of adjacent joints 70 in the vertical direction is longer than the distance L3 between the centers P of the low basis weight portions 25aL (L70 > L3). This makes it easier for the moisture absorbed from the skin-side layer 25a of the sheet portion 25 to move from the low basis weight portion 25aL to the non-skin-side layer 25b, reducing the discomfort of the wearer and the adverse effects on the skin caused by the moisture continuously contacting the wearer's skin. At the same time, in the vertical direction, compared with the case where the distance L70 between the centers 70c of the joints 70 is shorter than the distance L3 between the centers P of the low basis weight portions 25aL, when looking at the diaper 1 in the thickness direction, it is easier to provide a wider overlapping portion between the joint 70 and the low basis weight portion 25aL. Therefore, the possibility of reducing the bonding strength of the side joints SS (joints 70) on both sides in the left-right direction of the pair of waist portions 20 and 30 can be reduced.

[0103] Also, when there are a plurality of joints 70 intermittently in the vertical direction at the side joint SS of the pair of waist portions of the diaper 1, it is preferable that the area of the region Z defined by the straight line (virtual line in FIG. 6) connecting the centers P of four adjacent low basis weight portions 25aL in the vertical direction (longitudinal direction) and the horizontal direction (lateral direction) is larger than the minimum area of the joint 70. By doing so, compared with the case where the area of the region Z is made larger than the minimum area of the joint 70, when looking in the thickness direction, the overlapping region between the low basis weight portion 25aL and the joint 70 is more likely to be widened. The possibility that this overlapping region becomes too wide and the bonding strength of the side joint SS (joint 70) becomes excessively strong, making it difficult to separate the ventral waist portion 20 and the dorsal waist portion 30 after using the diaper 1, can be reduced.

[0104] On one hand, when there are a plurality of joints 70 intermittently in the vertical direction at the side joint SS of the pair of waist circumferential parts of the diaper 1, the area of the region Z defined by a straight line (virtual line in FIG. 6) connecting the centers P of four low basis weight parts 25aL adjacent to each other in the vertical direction (longitudinal direction) and the horizontal direction (lateral direction) may be smaller than the maximum area of the joint 70. By this, compared with the case where the area of the region Z is made larger than the maximum area of the joint 70, when looking at the diaper 1 in the thickness direction, it becomes easier to widely provide a region where the low basis weight part 25aL and the joint 70 overlap, and it becomes easier to increase the joint strength at the side joint SS (joint 70).

[0105] <Arrangement of the sheet part 25 in the diaper 1> FIGS. 7 to 10 are modified examples of the arrangement of the sheet member of the present invention. In each modified example, the sheet part 25 is a sheet member having the above-described characteristics.

[0106] (Modified Example 1) Figs. 7A and 7B are diagrams for explaining Modification Example 1 of the arrangement of the sheet portion 25 of the present invention. In Modification Example 1, a separate sheet member is not provided as the sheet portion 25, and the folded-back portion 22r (32r) of the ventral outer layer sheet 22 (dorsal outer layer sheet 32) is used as the sheet portion 25 (35). In this modification, at least the portion of the ventral outer layer sheet 22 (dorsal outer layer sheet 32) that becomes the sheet portion 25 (35) has a skin-side layer (cotton layer) 25a on the skin side and a non-skin-side layer 25b on the non-skin side in the thickness direction of the skin-side layer 25a. And a joint portion (not shown) where the sheet portion 25 (35), which is a part of the ventral outer layer sheet 22 (dorsal outer layer sheet 32), and the inner layer sheet 21 (adjacent sheet member) adjacent to the sheet portion 25 (35) from the non-skin surface side in the thickness direction are joined by welding or adhesion, and a non-joint portion (not shown) where the sheet portion 25 (35) and the inner layer sheet 21 (adjacent sheet member) are not joined by welding or adhesion are provided, so that the same operational effects as those of the above-described embodiment can be obtained. Note that the folded-back portion 22 (32r) that is the sheet portion 25 (35) of this modification is a portion where the tightening is strong at the ventral body circumference portion 20 (dorsal body circumference portion 30). Because the skin-side layer 25a is present on the skin contact surface of such a portion, the wearer can more vividly feel the softness of the skin-side fibers 25as such as cotton fibers. Also, because of the non-joint portion, it becomes easier to follow the movement of the body circumference, so the friction with the skin can be reduced and the fluffing of the skin-side fibers 25as such as cotton fibers can be suppressed. Note that in Modification Example 1, the sheet portion 25 (35) is configured to replace the folded-back portion 22r (32r), but it is not limited thereto. Whether or not the diaper 1 has the folded-back portion 22r (32r), the sheet portion 25 (35) may be arranged at the position shown in Fig. 7.

[0107] (Modification Example 2) FIG. 8 is a diagram for explaining a second modification of the arrangement of the sheet portion 25 of the present invention. In the second modification shown in FIG. 8, the sheet portion 25 (35) is not provided up to both left and right ends of the ventral body circumferential portion 20 (dorsal body circumferential portion 30), but is provided at the central portion in the left - right direction of the ventral body circumferential portion 20 (dorsal body circumferential portion 30) and so as to straddle the upper end 10e of the absorbent body 10 in the vertical direction. Since the upper end 10e of the absorbent body 10 is a portion where the unevenness is relatively large, by arranging the sheet portion 25 (35) so that at least the entire upper end 10e is covered, the friction against the skin during wearing can be suppressed, and the irritation to the skin can be reduced.

[0108] (Modification 3) FIG. 9 is a diagram for explaining a third modification of the arrangement of the sheet portion 25 of the present invention. In the third modification shown in FIG. 9, a sheet member that becomes the sheet portion 25 (35) is provided between the absorbent body 10 and the inner layer sheet 21. Further, the sheet member that becomes the sheet portion 25 is provided in the ventral body circumferential portion 20 between one end and the other end in the left - right direction of a pair of side joining portions SS and in the region from the upper end to the lower end in the vertical direction of the pair of side joining portions SS. In the dorsal body circumferential portion 30, the sheet member that becomes the sheet portion 35 is provided between one end and the other end in the left - right direction of a pair of side joining portions SS and in the region from the upper end to near the lower end in the vertical direction of the pair of side joining portions SS. With such a configuration, the skin - side layer 25a exists in most of the skin - contact surfaces in the regions of the ventral body circumferential portion 20 (dorsal body circumferential portion 30) other than the region where the absorbent body 10 is arranged, and the feel of the skin is improved. Also, since the sheet portion 25 (35) has a non - joined portion where it is not joined to the inner layer sheet 21 by welding or adhesion, the sheet portion 25 (35) can easily follow the movement of the wearer's body circumference, and the friction with the skin can be reduced. Thus, even if the proportion of the skin - side layer 25a in contact with the skin increases, the fluffing of the skin - side fibers 25as such as cotton fibers can be suppressed. In the body circumferential portions 20 and 30, instead of the inner layer sheets 21 and 31, the sheet portions 25 and 35 may be arranged as the sheets located closest to the skin side of the body circumferential portions 20 and 30.

[0109] Further, when the non-skin-side fibers 25bs are thermoplastic fibers, the diaper 1 has an adjacent member provided at a position overlapping the sheet portion 25 when viewed in the thickness direction. The diaper 1 is provided with a welded joint portion where the sheet portion 25 and the adjacent member are welded and joined in the thickness direction. The diaper 1 may be configured such that at least a part of the welded joint portion overlaps a portion where the low basis weight portion 25aL and the non-skin-side layer 25b overlap when viewed in the thickness direction. For example, in Modifications 1 to 3 shown in FIGS. 7 to 9, when the inner layer sheet 21 (or the ventral outer layer sheet 22) at a position overlapping the sheet portion 25 of the ventral body circumference portion 20 is used as the adjacent member when viewed in the thickness direction, a welded joint portion (not shown) where the sheet portion 25 and the inner layer sheet 21 (or the ventral outer layer sheet 22) are welded and joined in the thickness direction may be provided. In such a case, when viewed in the thickness direction, it is preferable that at least a part of the welded joint portion overlaps a portion where the low basis weight portion 25aL and the non-skin-side layer 25b of the sheet portion 25 overlap. Thereby, it is possible to reduce the risk of a decrease in the bonding strength of the welded joint portion for welding the sheet portion 25 and the inner layer sheet 21 (or the outer layer sheet 22).

[0110] In addition, in the above-described embodiments and Modifications 1 to 3, the sheet portion 25 is provided at the ventral body circumference portion 20 and the sheet portion 35 is provided at the dorsal body circumference portion 30, but the present invention is not limited to this. In each diaper 1, a configuration may be adopted in which only the sheet portion 25 is provided at the ventral body circumference portion 20 and the sheet portion 35 is not provided at the dorsal body circumference portion 30, or a configuration may be adopted in which only the sheet portion 35 is provided at the dorsal body circumference portion 30 and the sheet portion 25 is not provided at the ventral body circumference portion 20.

[0111] (Modification 4) FIG. 10 is a diagram for explaining Modification 4 of the arrangement of the sheet portion 25 of the present invention. In Modification 4 shown in FIG. 10, the sheet portion 25 is provided as the top sheet 12 of the absorbent body 10. Since the top sheet 12 is a member that contacts the skin of the wearer in the absorbent body 10, by providing the sheet portion 25 as the top sheet 12, the texture can be improved by the skin-side fibers 25as of the skin-side layer 25a, and the discomfort to the skin of the wearer and the adverse effects on the skin of the wearer can be reduced.

[0112] Note that the disposable diaper 1 of the modified example shown in FIG. 10 may have a squeezing member having a portion (not shown) squeezed in the thickness direction. Examples of the squeezing member include members such as the absorbent core 11. In the disposable diaper 1, a sheet portion 25 (top sheet 12) is provided closer to the skin side than the squeezing member (absorbent core 11), and in a portion where the low basis weight portion 25aL and the non-skin side layer 25b overlap when viewed in the thickness direction, a portion overlapping the squeezed portion of the squeezing member (absorbent core 11) may be provided. Generally, since the squeezed portion is a portion with a high fiber density, it becomes a portion that easily absorbs moisture due to capillary action. Therefore, when the squeezing member (absorbent core 11) has a portion with a high density due to squeezing, it becomes easier to move moisture from the sheet portion 25 (top sheet 12) to the squeezing member located on the non-skin side of the sheet portion 25.

[0113] <Regarding other aspects of the absorbent article 1> Regarding the absorbent article 1, in addition to the above-described aspects, the following aspects are also possible.

[0114] (Other aspect 1) An absorbent article 1 having a vertical direction and a thickness direction that intersect each other, and including an absorbent body 10, a ventral body circumferential portion 20 located on the ventral side of the wearer, and a dorsal body circumferential portion 30 located on the dorsal side of the wearer, wherein at least one of the ventral body circumferential portion 20 and the dorsal body circumferential portion 30 includes a cotton layer (skin side layer) 25a having cotton fibers (skin side fibers) 25as as a base material, and a sheet portion 25 (35) at least a part of which is disposed above the absorbent body 10 in the vertical direction is provided. When a region disposed above the absorbent body 10 in the vertical direction in the sheet portion 25 (35) is defined as an upper disposed region, the absorbent article 1 may be characterized by having a joined portion where the upper disposed region and an adjacent sheet member adjacent to the upper disposed region from the non-skin side in the thickness direction are joined by welding or adhesion, and a non-joined portion where the upper disposed region and the adjacent sheet member are not joined by welding or adhesion. According to this aspect, the non-bonded part of the sheet portion in contact with the skin is a part that is easily deformed freely. When movement occurs in the torso area, the non-bonded part follows such movement to reduce friction with the skin, thereby suppressing the fluffing of the cotton fibers 25as. At the same time, by having a bonded part, the shedding of the cotton fibers 25as can also be suppressed. Furthermore, by continuously contacting the skin with the cotton layer 25a while reducing friction with the skin, the softness of the cotton can be felt while suppressing irritation to the skin.

[0115] (Other Aspect 2) In the unfolded state and the extended state, the absorbent article 1 may have a total area of the non-bonded parts larger than the total area of the bonded parts when viewed in plan in the upper placement area. According to this aspect, since the total area of the non-bonded parts is larger, there are more parts that can follow the movement when movement occurs around the torso, thereby reducing friction with the skin and suppressing the fluffing of the cotton layer 25a.

[0116] (Other Aspect 3) In the vertical direction, the absorbent article 1 may have a total length of the bonded parts longer than the total length of the non-bonded parts. According to this aspect, providing more non-bonded parts can suppress the fluffing of the cotton layer 25a. On the other hand, there is a risk that the bond between the sheet portion 25(35) and the adjacent sheet member may peel off. By making the total length of the bonded parts in the vertical direction longer than the total length of the non-bonded parts, the peeling of the bond can be made difficult.

[0117] (Other Aspect 4) The sheet portion may have a non-skin-side layer 25b located on the non-skin side in the thickness direction of the cotton layer 25a, and the average fiber length of the non-skin-side fibers 25bs, which are the base fibers of the non-skin-side layer 25b, may be longer than the average fiber length of the cotton fibers 25as. According to this aspect, by joining the cotton fibers 25as with fibers having a long average fiber length, the durability of the cotton layer 25a is improved, and the cotton fibers 25as are less likely to fall off. Also, in the joining of the sheet portion 25(35) and the adjacent sheet member, since the average fiber length of the non-skin-side fibers 25bs located on the non-skin side in the sheet portion 25(35) is long, the joining is less likely to peel off, and the followability to the adjacent sheet member is improved.

[0118] (Other Aspect 5) The sheet portion 25(35) may have a non-skin-side layer 25b located on the non-skin side in the thickness direction of the cotton layer 25a, and the absorbent article 1 may be such that the thermal conductivity of the cotton fibers 25as is lower than the thermal conductivity of the non-skin-side fibers 25bs which are the base fibers of the non-skin-side layer 25b. According to this aspect, since the thermal conductivity of the cotton fibers 25as that come into contact with the wearer's skin is low, even if the cotton layer 25a gets wet with sweat or the like during wearing, the cotton layer 25a is not likely to become cold immediately. Also, since the non-skin-side fibers 25bs in the non-skin-side layer 25b have a higher thermal conductivity than the cotton fibers 25as, heat exchange is likely to be promoted. Therefore, the heat that has moved to the non-skin-side layer 25b is released further to the non-skin side than the non-skin-side layer 25b, making it difficult for heat to accumulate in the sheet portion 25.

[0119] (Other Aspect 6) The sheet portion 25(35) may have a non-skin-side layer 25b located on the non-skin side in the thickness direction of the cotton layer 25a, and the absorbent article 1 may be such that the hydrophilicity of the cotton fibers 25as which are the base fibers of the cotton layer 25a is higher than the hydrophilicity of the non-skin-side fibers 25bs which are the base fibers of the non-skin-side layer 25b. According to this aspect, by disposing the cotton layer 25a having the cotton fibers 25as with high hydrophilicity as the base fibers on the surface that comes into contact with the wearer's skin, the water absorption is improved, and since the hydrophilicity of the non-skin-side fibers 25bs which are the base fibers of the non-skin-side layer 25b is lower than that of the cotton fibers 25as, when the moisture such as sweat absorbed by the cotton fibers 25as moves to the non-skin side, the non-skin-side layer 25b does not retain excessive moisture and promotes transpiration, making it less likely to feel stuffy.

[0120] (Other Aspect 7) The absorbent article 1 may have a ratio of cotton fibers 25as in the sheet portion 25(35) of less than 50% by mass. According to this aspect, by including the cotton fibers 25as, a good texture can be felt, and at the same time, by reducing the mass ratio of the cotton fibers 25as, the fuzzing of the cotton layer 25a is suppressed.

[0121] (Other aspect 8) The absorbent article 1 may have a predetermined basis weight portion 25aP provided with cotton fibers 25as of a predetermined basis weight and a low basis weight portion 25aL having a lower basis weight of cotton fibers 25as than the predetermined basis weight portion 25aP. According to this aspect, by having the low basis weight portion 25aL with a low basis weight, the shedding of the cotton fibers 25as with a short average fiber length can be suppressed. Therefore, it is possible to achieve both a comfortable texture by the cotton fibers 25as provided in the predetermined basis weight portion 25aP and the suppression of the shedding of the cotton fibers 25as.

[0122] (Other aspect 9) The absorbent article 1 has a left - right direction orthogonal to the up - down direction and the thickness direction, and at least one of the ventral body - surrounding portion 20 and the dorsal body - surrounding portion 30 has an inner layer sheet 21, outer layer sheets 22, 32 disposed on the non - skin side of the inner layer sheet 21, and a plurality of body - surrounding elastic members 23, 33 arranged at intervals in the up - down direction and stretchable in the left - right direction between the inner layer sheet 21 and the outer layer sheets 22, 32. In the cotton layer 25a, a plurality of low basis weight portions 25aL are provided at intervals in the up - down direction, and the minimum value of the distance P between the centers in the up - down direction of adjacent low basis weight portions 25aL in the up - down direction is smaller than the minimum value of the distance between the centers in the up - down direction of adjacent body - surrounding elastic members 23, 33 in the up - down direction. According to this aspect, by providing a plurality of low basis weight portions 25aL at small intervals in the up - down direction, the shedding of the cotton fibers 25as with a short average fiber length can be further suppressed, and the irritation to the skin caused by fiber shedding can be further suppressed.

[0123] (Other aspect 10) The sheet part 25(35) may be an absorbent article 1 which is a sheet member disposed closer to the skin side than the inner layer sheet 21. According to this aspect, since the waist elastic members 23, 33 are disposed between the inner layer sheet 21 and the outer layer sheets 22, 32, there exists a region where interference occurs between the waist elastic members 23, 33 and the sheet part (sheet member) including the cotton layer 25a. Thereby, it is possible to avoid excessive expansion and contraction of the cotton layer 25a on the skin surface side, reduce the friction between the cotton layer 25a and the skin, and suppress the shedding and fuzzing of the cotton fibers 25as.

[0124] (Other aspect 11) The sheet part 25(35) is disposed at a distance downward from at least one of the upper ends in the vertical direction of the ventral waist part 20 and the dorsal waist part 30. When the region from the upper end of the ventral waist part 20 or the dorsal waist part 30 where the sheet part 25 is provided to the upper end of the sheet part 25 in the vertical direction is defined as a non - disposed region, and the region from the upper end to the lower end of the sheet part 25 of the ventral waist part 20 or the dorsal waist part 30 where the sheet part is provided in the vertical direction is defined as a disposed region, the portion closest to the skin surface side in the non - disposed region contains hydrophobic fibers, and the magnitude of the force required to extend the non - disposed region with a unit width in the vertical direction by a unit length in the horizontal direction is greater than the magnitude of the force required to extend the disposed region with a unit width in the vertical direction by a unit length in the horizontal direction. The absorbent article 1 may be such. According to this aspect, the portion closest to the skin surface side of the non - disposed region with strong tightening contains hydrophobic fibers, which reduces stickiness and suppresses discomfort to the wearer's body. The disposed region of the sheet part where fuzzing is likely to occur when the tightening becomes strong has a reduced tightening force, reducing friction with the skin and suppressing the fuzzing of cotton fibers.

[0125] (Other aspect 12) In the vertical direction, the absorbent article 1 may be such that the length of the sheet part 25(35) is half or less of the length of the ventral waist part 20 or the dorsal waist part 30. According to this aspect, the cotton layer 25a of the sheet portion 25 suppresses fuzzing by reducing the friction against the skin while suppressing the length of the cotton layer 25a. Therefore, it is possible to experience the good feel of the cotton layer 25a on the skin, reduce the irritation to the skin, and prevent fuzzing.

[0126] (Other Aspect 13) At least one of the ventral body circumferential portion 20 and the dorsal body circumferential portion 30 has an inner layer sheet 21, an outer layer sheet 22(32) disposed on the non-skin side of the inner layer sheet 21, and a folded-back portion 22r(32r) where the upper and lower ends of the outer layer sheet 22 are folded back to the skin side. In the vertical direction, the absorbent article 1 may have a length of the sheet portion 25 longer than the length of the folded-back portion 22r. According to this aspect, by providing a sheet portion longer than the vertical length of the folded-back portion 22r, it becomes easier to experience the good feel of the cotton layer 25a.

[0127] (Other Aspect 14) At least one of the ventral body circumferential portion 20 and the dorsal body circumferential portion 30 has an inner layer sheet 21, an outer layer sheet 22(32) disposed on the non-skin side of the inner layer sheet 21, and a folded-back portion 22r(32r) where the upper and lower ends of the outer layer sheet 22 are folded back to the skin side. In the vertical direction, the absorbent article 1 may have a length of the sheet portion 25 shorter than the length of the folded-back portion 22r. According to this aspect, by not arranging the sheet portion 25 to be excessively long in the vertical direction, the possibility of fuzzing of the cotton layer 25a is further reduced.

[0128] (Other Aspect 15) The sheet portion 25 may be an absorbent article 1 that straddles the upper and lower ends of the absorbent body 10 in the vertical direction in at least one of the ventral body circumferential portion 20 and the dorsal body circumferential portion 30. According to this aspect, the upper end of the absorbent body 10 is a portion where the unevenness is relatively large. By covering the upper end, the friction against the skin can be suppressed and the irritation to the skin can be reduced.

[0129] (Other Aspect 16) The absorbent article 1 may be such that no surface fastener is provided between the sheet portion 25(35) and the adjacent sheet member in the thickness direction. According to this aspect, providing a surface fastener increases rigidity and makes it difficult to follow the movement of the adjacent sheet member. However, not providing such a surface fastener improves the followability.

[0130] (Other Aspect 17) An absorbent article 1 having an absorbent body 10, a ventral body circumferential portion 20 located on the ventral side of the wearer, and a dorsal body circumferential portion 30 located on the dorsal side of the wearer, having a sheet portion 25(35) disposed on the most skin-side of at least one of the ventral body circumferential portion 20 and the dorsal body circumferential portion 30, and the sheet portion 25(35) and an adjacent sheet member adjacent to the non-skin side of the sheet portion 25(35) are joined by adhesion or welding. The sheet portion 25(35) has a skin-side layer 25a that contacts the skin of the wearer and a non-skin-side layer 25b that is located on the non-skin side of the skin-side layer. The hydrophilicity of the skin-side fibers 25as, which are the base fibers of the skin-side layer 25a, is higher than the hydrophilicity of the non-skin-side fibers 25bs, which are the base fibers of the non-skin-side layer 25b. The absorbent article 1 may be such that. According to this aspect, since the skin-side layer 25a has a high hydrophilicity of the skin-side fibers 25as, it is easy to absorb sweat and excretions. On the other hand, since the non-skin-side layer 25b has a lower hydrophilicity of the non-skin-side fibers 25bs, which are the base fibers, than the skin-side fibers 25as, even if the sheet portion 25 gets wet, the adhesive strength with the adjacent sheet member can be maintained, preventing the sheet portion 25 from peeling off. Thereby, the original function of the sheet portion 25 can be exhibited, and the wearing feeling can be prevented from being impaired due to the peeling of the sheet portion 25.

[0131] (Other Aspect 18) The absorbent article 1 may be such that the content rate of the skin-side fibers 25as in the sheet portion 25 is 50 mass% or less. According to this aspect, if the mass ratio of the skin-side fibers 25as with high hydrophilicity becomes too high throughout the sheet part 25, when the sheet part 25 gets wet, the adhesive strength with the adjacent sheet member may become weak. However, by lowering the mass ratio of the skin-side fibers 25as throughout the sheet part 25, this can be avoided.

[0132] (Other aspect 19) The absorbent article 1 may be characterized in that at least a part of the skin-side fibers 25as in the skin-side layer 25a is present on the same surface as the non-skin-side surface of the non-skin-side layer 25b. According to this aspect, the moisture absorbed by the skin-side layer 25a can be quickly transferred to the non-skin-side layer 25b along the extending skin-side fibers 25as. Thereby, the excess moisture in the skin-side layer 25a can be removed to the non-skin-side layer 25b. Since the non-skin-side layer 25b has a low proportion of skin-side fibers 25as, it does not hold too much of the transferred moisture and can maintain the adhesive strength with the adjacent sheet member. Therefore, it is possible to prevent the wearing feeling from being impaired due to the unexpected peeling of the sheet part 25.

[0133] (Other aspect 20) The absorbent article 1 may be characterized in that when the welded parts where the fibers are welded to each other in the skin-side layer 25a and the non-skin-side layer 25b are defined as the welded parts, the total volume of the welded parts per unit volume of the non-skin-side layer 25b is larger than the total volume of the welded parts per unit volume of the skin-side layer 25a. Note that the "fibers" of the skin-side layer 25a and the non-skin-side layer 25b refer to the skin-side fibers 25as, the non-skin-side fibers 25bs, and other fibers included in the skin-side layer 25a and the non-skin-side layer 25b. For example, in the case where the welded part in the skin-side layer 25a is such that the skin-side layer 25a has thermoplastic fibers other than cotton fibers (skin-side fibers) 25as, it may be the part where the thermoplastic fibers in the skin-side layer 25a and the non-skin-side fibers 25bs which are thermoplastic fibers in the non-skin-side layer 25b are welded. In the case where the skin-side layer 25a is formed only of cotton fibers (skin-side fibers) 25as, there is no state where a welded part exists. According to this aspect, since the skin-side layer 25a has few (or no) welded portions, moisture easily enters between the fibers and it easily absorbs moisture from the wearer's skin. On the other hand, the non-skin-side layer 25b has welded portions to ensure surface smoothness and easily maintain adhesive strength even when the sheet portion is wet. Also, since the presence of welded portions in the non-skin-side layer 25b improves the strength of the entire sheet portion 25, it is possible to make it difficult for the adhesion to an adjacent sheet member to peel off.

[0134] (Other Aspect 21) The absorbent article 1 may be characterized in that the ratio of the total volume of the welded portions in the total volume of the non-skin-side layer 25b is 5% or more and 25% or less. According to this aspect, due to the presence of the welded portions at such a ratio, the non-skin-side layer 25b ensures surface smoothness, easily maintains adhesive strength even when the sheet portion 25 is wet, and also improves the strength of the entire sheet portion 25. Thereby, the adhesion to an adjacent sheet member becomes difficult to peel off.

[0135] (Other Aspect 22) The non-skin-side layer 25b has a non-skin-side layer skin-side portion located on the skin side and a non-skin-side layer non-skin-side portion located on the non-skin side in the thickness direction of the non-skin-side layer 25b, and the fiber density of the non-skin-side fibers 25bs of the non-skin-side layer non-skin-side portion is higher than the fiber density of the non-skin-side fibers 25bs of the non-skin-side layer skin-side portion. The absorbent article 1 may be such. According to this aspect, the non-skin-side layer non-skin-side portion is the portion on the side that adheres to the adjacent sheet member, and since the fiber density of the non-skin-side portion 25bB is higher among the non-skin-side layer 25b, the adhesive strength to the adjacent sheet member can be increased.

[0136] (Other Aspect 23) The non-skin-side layer 25b has a non-skin-side layer skin-side portion located on the skin side and a non-skin-side layer non-skin-side portion located on the non-skin side in the thickness direction of the non-skin-side layer 25b, and the fiber density of the non-skin-side fibers 25bs of the non-skin-side layer skin-side portion is higher than the fiber density of the non-skin-side fibers 25bs of the non-skin-side layer non-skin-side portion. The absorbent article 1 may be such. According to this aspect, a higher fiber density makes it easier to draw in liquid. When the fiber density of the non-skin side layer skin side portion is high, a portion with a high fiber density of the non-skin side fibers 25bs is arranged adjacent to the skin side layer 25a with a high hydrophilicity. In this way, the moisture absorbed by the skin side fibers 25as can be drawn into the non-skin side layer skin side portion, reducing the moisture content of the skin side layer 25a and suppressing the stickiness and other sensations of the portion touching the skin.

[0137] (Other Aspect 24) The non-skin side layer 25b has a non-skin side layer skin side portion located on the skin side and a non-skin side layer non-skin side portion located on the non-skin side in the thickness direction of the non-skin side layer 25b. The absorbent article 1 may be characterized in that the hydrophilicity of the non-skin side fibers 25bs in the non-skin side layer skin side portion is higher than the hydrophilicity of the non-skin side fibers 25bs in the non-skin side layer non-skin side portion. According to this aspect, the non-skin side layer skin side portion is the portion on the side that contacts the skin side fibers 25as of the skin side layer 25a. By increasing the hydrophilicity of the non-skin side fibers 25bs in the non-skin side layer skin side portion, it becomes easier for moisture to transfer from the skin side fibers 25as to the non-skin side fibers 25bs. The transferred moisture is less likely to remain in the non-skin side layer non-skin side portion with low hydrophilicity and is more likely to promote transpiration. Since it is difficult for moisture to accumulate in the non-skin side layer non-skin side portion, it becomes easier to maintain the adhesion between the non-skin side layer 25b and the adjacent sheet member.

[0138] (Other Aspect 25) The absorbent article 1 may be characterized in that the skin side fibers 25as are cotton fibers, and the non-skin side fibers 25bs are hydrophobic fibers containing at least one of polypropylene, polyethylene, and polyurethane, or fibers obtained by hydrophilically treating at least one of polypropylene, polyethylene, and polyurethane. According to this aspect, the skin-side layer 25a contains cotton fibers, making it easier to absorb moisture from the skin. The non-skin-side layer 25b contains the above hydrophobic fibers (or hydrophilized fibers), so that after the excessive moisture in the skin-side layer 25a transfers to the non-skin-side layer 25b, the moisture can be removed without being retained, maintaining the adhesion strength with the adjacent sheet member. Therefore, it is possible to prevent the wearing feeling from being impaired due to the unexpected peeling of the sheet portion 25.

[0139] (Other aspect 26) The non-skin-side layer 25b has a predetermined basis weight portion provided with non-skin-side fibers 25bs of a predetermined basis weight and a low basis weight portion where the basis weight of the non-skin-side fibers 25bs is lower than that of the predetermined basis weight portion 25. The absorbent article 1 may be characterized in that the low basis weight portion 25aL of the skin-side layer 25a and the low basis weight portion of the non-skin-side layer 25b have an overlapping portion when viewed in the thickness direction of the absorbent article 1. According to this aspect, in the overlapping portion, it promotes drawing the moisture absorbed by the skin-side layer 25a from the low basis weight portion 25aL of the skin-side layer 25a to the low basis weight portion of the non-skin-side layer 25b. Therefore, the adhesion strength can be maintained by removing the moisture from the sheet portion 25 more quickly, preventing the occurrence of peeling of the sheet portion 25.

[0140] ===Others=== The above embodiments are for facilitating the understanding of the present invention and are not for limiting the interpretation of the present invention. The present invention can be changed and improved without departing from its gist, and it goes without saying that the present invention includes its equivalents.

Explanation of reference numerals

[0141] 1 Diaper, (pant-type disposable diaper, absorbent article) 10 Absorbent main body, 10e Upper end 11 Absorbent core (absorbent body) 12 Top sheet 13 Back sheet 14 Outer wrapper sheet 15 Elastic member around the legs 18 Outer package 20 Ventral torso circumference part 20e Upper end 21 Inner layer sheet 22 Ventral outer layer sheet, 22r Folded-back part 23 Torso circumference elastic member 25 Sheet part 25a Skin side layer (cotton layer) 25aL Low basis weight part 25aP Predetermined basis weight part 25as Skin side fiber (cotton fiber) 25b Non-skin side layer, 25bs Non-skin side fiber 30 Dorsal torso circumference part 32 Dorsal outer layer sheet, 32r Folded-back part 33 Torso circumference elastic member 34 Hind leg circumference elastic member 35 Sheet part 40 Lower thigh part SS Side joint part (joint part)

Claims

1. A sheet member for an absorbent article, having a skin-side layer capable of contacting the skin of a wearer and a non-skin-side layer provided on the non-skin side of the skin-side layer, wherein the hydrophilicity of the skin-side fibers, which are the base fibers of the skin-side layer, is higher than the hydrophilicity of the non-skin-side fibers, which are the base fibers of the non-skin side layer, the skin-side layer has a predetermined basis weight portion provided with the skin-side fibers having a predetermined basis weight and a low basis weight portion having a lower basis weight of the skin-side fibers than the predetermined basis weight portion, in a thickness direction view, having a portion where the predetermined basis weight portion overlaps with the non-skin side layer and a portion where the low basis weight portion overlaps with the non-skin side layer A sheet member characterized by the above.

2. The sheet member according to claim 1, characterized by having a portion where the skin-side fibers and the non-skin side fibers are entangled.

3. The sheet member according to claim 1 or 2, characterized in that the skin-side fibers are cotton fibers.

4. The sheet member according to claim 1 or 2, the sheet member has a longitudinal direction and a lateral direction orthogonal to the thickness direction, in the longitudinal direction, the predetermined basis weight portion and the low basis weight portion are alternately arranged, in the lateral direction, the predetermined basis weight portion and the low basis weight portion are alternately arranged. A sheet member characterized by the above.

5. The sheet member according to claim 1 or 2, characterized in that the density of the skin-side fibers in the low basis weight portion is lower than the density of the skin-side fibers in the predetermined basis weight portion.

6. The sheet member according to claim 1 or 2, characterized in that at least a part of the non-skin side fibers is present on the skin side surface of the skin-side layer.

7. The sheet member according to claim 1 or 2, wherein no adhesive is provided on the sheet member.

8. The sheet member according to claim 1 or 2, wherein no portion obtained by compressing a part of the sheet member in the thickness direction is provided on the sheet member.

9. The sheet member according to claim 1 or 2, wherein the sheet member has a sheet compression portion obtained by compressing a part of the skin-side layer in the thickness direction on the skin-side layer.

10. The sheet member according to claim 1 or 2, wherein the absorbent article has a hydrophilic member including fibers having a higher hydrophilicity than the non-skin-side fibers, and in the absorbent article, the sheet member is used on the skin side in the thickness direction of the hydrophilic member and at a position overlapping the hydrophilic member when viewed in the thickness direction.

11. The sheet member according to claim 1 or 2, wherein the absorbent article has a non-hydrophilic member including fibers having a lower hydrophilicity than the non-skin-side fibers, and in the absorbent article, the sheet member is used on the skin side in the thickness direction of the non-hydrophilic member and at a position overlapping the non-hydrophilic member when viewed in the thickness direction.

12. The sheet member according to claim 1 or 2, wherein the absorbent article has a stretchable member, and in the absorbent article in a deployed and stretched state, the sheet member is used at a position overlapping at least a part of the stretchable member when viewed in the thickness direction.

13. The sheet member according to claim 1 or 2, The absorbent article has a squeezing member having a portion squeezed in the thickness direction. In the absorbent article, the sheet member is provided closer to the skin side than the squeezing member. A sheet member, wherein a portion where the low basis weight portion and the non-skin side layer overlap when viewed in the thickness direction has a portion overlapping with the squeezed portion of the squeezing member.

14. The sheet member according to claim 1 or 2, wherein the sheet member has a portion where the skin side fibers and the non-skin side fibers are melt-bonded.

15. The sheet member according to claim 1 or 2, wherein the non-skin side fibers are thermoplastic fibers, and in the absorbent article, there is an adjacent member provided at a position overlapping the sheet member when viewed in the thickness direction. The absorbent article includes a welded joint portion where the sheet member and the adjacent member are welded and joined in the thickness direction. A sheet member, wherein a portion where the low basis weight portion and the non-skin side layer overlap when the absorbent article is viewed in the thickness direction overlaps at least a part of the welded joint portion.

16. The sheet member according to claim 1 or 2, wherein the non-skin side fibers are thermoplastic fibers, and the absorbent article has a joint portion where both side portions in the left-right direction of a pair of body circumferential portions are welded and joined. When viewed in the thickness direction, the sheet member is used at a position overlapping at least a part of the joint portion. A sheet member, wherein the joint portion overlaps at least a part of a portion where the low basis weight portion and the non-skin side layer overlap.

17. The sheet member according to claim 16, wherein the pair of body circumferential portions has a plurality of joint portions intermittently in the vertical direction. A sheet member, wherein, in the vertical direction, the distance between the centers of adjacent joints is longer than the distance between the centers of the low basis weight portions.

18. The sheet member according to claim 16, wherein the joints are provided intermittently in the vertical direction, the sheet member has a longitudinal direction and a lateral direction orthogonal to the thickness direction, and an area of a region defined by a straight line connecting the centers of four adjacent low basis weight portions in the longitudinal direction and the lateral direction is smaller than a maximum area of the joints.

19. The sheet member according to claim 16, wherein the joints are provided intermittently in the vertical direction, the sheet member has a longitudinal direction and a lateral direction orthogonal to the thickness direction, and an area of a region defined by a straight line connecting the centers of four adjacent low basis weight portions in the longitudinal direction and the lateral direction is larger than a minimum area of the joints.

20. An absorbent article having an absorber and a sheet member provided on the skin side of the absorber, wherein the sheet member has a skin-side layer capable of contacting the wearer's skin and a non-skin-side layer provided on the non-skin side of the skin-side layer, a hydrophilicity of skin-side fibers, which are base fibers of the skin-side layer, is higher than a hydrophilicity of non-skin-side fibers, which are base fibers of the non-skin-side layer, the skin-side layer has a predetermined basis weight portion including the skin-side fibers having a predetermined basis weight and a low basis weight portion having a lower basis weight of the skin-side fibers than the predetermined basis weight portion, and, when viewed in the thickness direction, has a portion where the predetermined basis weight portion overlaps with the non-skin-side layer and a portion where the low basis weight portion overlaps with the non-skin-side layer. Absorbent article, characterized by the above.

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