Sheet member and absorbent article

Abstract

Provided is a sheet member 25 for an absorbent article, comprising a skin-side layer 25a that can come into contact with the skin of a wearer and a non-skin-side layer 25b provided on the non-skin side of the skin-side layer 25a. The sheet member 25 is characterized in that: skin-side fibers 25as, which are base fibers of the skin-side layer 25a, have a higher hydrophilicity than non-skin-side fibers 25bs, which are base fibers of the non-skin-side layer 25b; the skin-side layer 25a has specific-basis-weight portions 25aP including the skin-side fibers 25as with a specific basis weight and low-basis-weight portions 25aL including the skin-side fibers 25as with a lower basis weight than the specific-basis-weight portions 25aP; and the sheet member 25 has areas where the specific-basis-weight portions 25aP and the non-skin-side layer 25b overlap each other, and areas where the low-basis-weight portions 25aL and the non-skin-side layer 25b overlap each other when viewed in the thickness direction.

Description

Sheet member and absorbent article

[0001] The present invention relates to a sheet member and an absorbent article.

[0002] Sheet members for absorbent articles come into contact with the wearer's skin and absorb moisture such as sweat while the wearer is wearing the sheet. 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. The sweat-absorbing sheet in Patent Document 1 transfers absorbed sweat from the inner layer located on the skin side to the outer layer located on the non-skin side, thereby preventing moisture from remaining on the skin side of the sweat-absorbing sheet.

[0003] Japanese Patent Application Laid-Open No. 2001-327534

[0004] In general, hydrophobic fibers are inferior in feel to hydrophilic fibers, and therefore, there is a demand for improved feel of sweat-absorbent sheets that come into contact with the skin. However, because hydrophilic fibers have the property of easily absorbing and retaining moisture, it has been difficult to provide hydrophilic fibers on the skin-side surface of a sweat-absorbent sheet.

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

[0006] The main invention for achieving the above object is 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 base fibers of the skin-side layer, is higher than the hydrophilicity of the non-skin-side fibers, which are base fibers of the non-skin-side layer, the skin-side layer has a predetermined basis weight portion having the skin-side fibers of a predetermined basis weight and a low basis weight portion having a basis weight of the skin-side fibers lower than that of the predetermined basis weight portion, and the sheet member has, in the thickness direction, a portion where the predetermined basis weight portion and the non-skin-side layer overlap and a portion where the low basis weight portion and the non-skin-side layer overlap. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[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.

[0008] 4A is a schematic perspective view of a pants-type disposable diaper 1. FIG. 4B is a schematic plan view of the diaper 1 in an unfolded and stretched state, as seen from the skin side of a wearer. FIG. 4C is a schematic cross-sectional view taken along line A-A in FIG. 2. FIG. 4D is a schematic cross-sectional view of the sheet portion 25. FIG. 4E is a diagram illustrating the sheet portion 25 as seen from the skin side. FIG. 4F is an enlarged schematic view of a portion X in FIG. 2. FIG. 4C is a first variation of the arrangement of the sheet portion 25 of the present invention. FIG. 4D is a second variation of the arrangement of the sheet portion 25 of the present invention. FIG. 4E is a third variation of the arrangement of the sheet portion 25 of the present invention. FIG. 4F is a fourth variation of the arrangement of the sheet portion 25 of the present invention.

[0009] The present specification and the accompanying drawings make at least the following clear: (Aspect 1) A sheet member for an absorbent article having a skin-side layer that can come into contact with the skin of a wearer and a non-skin-side layer that is provided on the non-skin-side side of the skin-side layer, wherein the hydrophilicity of the skin-side fibers that are base fibers of the skin-side layer is higher than the hydrophilicity of the non-skin-side fibers that are base fibers of the non-skin-side layer, the skin-side layer has a predetermined basis weight section including the skin-side fibers of a predetermined basis weight and a low basis weight section in which the basis weight of the skin-side fibers is lower than that of the predetermined basis weight section, and the sheet member has, when viewed in the thickness direction, a portion where the predetermined basis weight section and the non-skin-side layer overlap and a portion where the low basis weight section and the non-skin-side layer overlap.

[0010] According to the sheet member of aspect 1, the highly hydrophilic skin-side layer improves the absorbency and feel of the sheet member, while also facilitating the transfer of moisture absorbed by the skin-side layer from the low basis weight portion to the non-skin side of the sheet member, thereby reducing the risk of moisture absorbed by the sheet member remaining in contact with the wearer's skin and reducing discomfort and adverse effects on the wearer's skin.

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

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

[0013] (Aspect 3) The sheet member according to aspect 1 or 2, wherein the skin side fibers are cotton fibers.

[0014] According to the sheet member of aspect 3, the fiber shape of the skin-side fiber of the skin-side layer that can come into contact with the wearer's skin is rounded cotton fiber, which feels good against the wearer's skin and reduces irritation to the wearer's skin when worn.

[0015] (Aspect 4) The sheet member is any of aspects 1 to 3, characterized in that the sheet member has a vertical direction and a horizontal direction perpendicular to the thickness direction, the predetermined basis weight portions and the low basis weight portions are alternately arranged in the vertical direction, and the predetermined basis weight portions and the low basis weight portions are alternately arranged in the horizontal direction.

[0016] According to the sheet member of aspect 4, the specified basis weight portion of the skin-side layer improves water absorbency and feel, while facilitating the transfer of moisture absorbed by the skin-side layer from the low basis weight portion to the non-skin-side layer, thereby reducing the risk of moisture absorbed by the sheet member remaining in contact with the wearer's skin and reducing discomfort and adverse effects on the wearer's skin.

[0017] (Aspect 5) The sheet member according to any one of Aspects 1 to 4, wherein 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.

[0018] According to the sheet member of aspect 5, the skin-side layer improves water absorbency and feel, while the moisture absorbed by the skin-side layer is more easily transferred from the low basis weight portion to the non-skin-side layer, thereby reducing the risk of moisture absorbed by the sheet member remaining in contact with the wearer's skin and reducing discomfort and adverse effects on the wearer's skin.

[0019] (Aspect 6) The sheet member according to any one of aspects 1 to 5, wherein at least a portion of the non-skin side fibers are present on the skin side surface of the skin side layer.

[0020] According to the sheet member of aspect 6, absorbed liquid can be easily transferred from the skin-side layer to the non-skin-side layer, thereby reducing the risk of moisture absorbed by the sheet member remaining in contact with the wearer's skin, and reducing discomfort and adverse effects on the wearer's skin.

[0021] (Aspect 7) The sheet member according to any one of Aspects 1 to 6, wherein the sheet member is not provided with an adhesive.

[0022] According to the sheet member of aspect 7, it is possible to reduce the risk of the sheet member becoming hard and the risk of the adhesive interfering with moisture absorption, while suppressing irritation to the skin of the wearer of an absorbent article using this sheet member.

[0023] (Embodiment 8) The sheet member according to any one of embodiments 1 to 7, wherein the sheet member does not have a portion where the sheet member is compressed in the thickness direction.

[0024] According to the sheet member of aspect 8, the risk of the sheet member becoming hard can be reduced, and irritation to the skin of a wearer of an absorbent article using this sheet member can be suppressed.

[0025] (Aspect 9) The sheet member according to any one of Aspects 1 to 7, wherein the sheet member has the skin side layer and a sheet compressed portion obtained by compressing a part of the skin side layer in the thickness direction.

[0026] According to the sheet member of Aspect 9, the risk of separation between the skin side layer and the non-skin side layer can be reduced.

[0027] (Aspect 10) The absorbent article is a sheet member according to any one of aspects 1 to 9, characterized in that the absorbent article has a hydrophilic member having fibers that are more hydrophilic than the non-skin-side fibers, and the sheet member is used in the absorbent article on the skin side of the hydrophilic member in the thickness direction and in a position that overlaps the hydrophilic member when viewed in the thickness direction.

[0028] According to the sheet member of aspect 10, when the absorbent article is worn, moisture absorbed from the sheet member side can be more easily transferred to the non-skin side, thereby reducing the discomfort and adverse effects caused by moisture continuing to adhere to the wearer's skin.

[0029] (Aspect 11) The absorbent article is a sheet member according to any one of aspects 1 to 9, characterized in that the absorbent article has a non-hydrophilic member having fibers that are less hydrophilic than the non-skin-side fibers, and the sheet member is used in the absorbent article on the skin side of the non-hydrophilic member in the thickness direction and in a position that overlaps the non-hydrophilic member when viewed in the thickness direction.

[0030] According to the sheet member of Aspect 11, the non-hydrophilic member is provided on the non-skin side of the non-skin side layer, which makes it easier to prevent moisture absorbed from the sheet member side from migrating from the non-skin side layer to the non-hydrophilic member when the absorbent article is worn, thereby reducing the risk of the non-skin side of the absorbent article becoming sticky. Furthermore, since the low basis weight portion has a low basis weight of skin-side fibers, the low basis weight portion is thin and easily recessed toward the non-skin side, thereby reducing the risk of moisture continuing to adhere to the wearer's skin. This makes it easier to reduce discomfort on both the skin side and non-skin side of the absorbent article when worn.

[0031] (Aspect 11) The absorbent article is the sheet member of any one of Aspects 1 to 10, characterized in that the absorbent article has a stretchable elastic member, and the sheet member is used in a position overlapping at least a portion of the stretchable member when viewed in the thickness direction of the absorbent article in an unfolded and stretched state.

[0032] According to the sheet member of aspect 11, the sheet member improves the feel of the absorbent article against the skin, and by forming wrinkles in at least a portion of the sheet member, the breathability of the sheet member is improved, thereby reducing stuffiness and irritation to the skin when the absorbent article is worn.

[0033] (Aspect 12) The absorbent article is a sheet member according to any one of aspects 1 to 11, characterized in that it has a compression member having a portion compressed in the thickness direction, the sheet member is provided in the absorbent article on the skin side of the compression member, and the portion where the low basis weight portion and the non-skin side layer overlap in the thickness direction has a portion that overlaps with the compressed portion of the compression member.

[0034] According to the sheet member of Aspect 12, the compressing member has a portion with a high density due to compression, which facilitates the transfer of moisture from the sheet member to the compressing member due to capillary action.

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

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

[0037] (Aspect 14) The sheet member of any of Aspects 1 to 13, wherein the non-skin side fibers are thermoplastic fibers, the absorbent article has an adjacent member that is arranged at a position that overlaps the sheet member when viewed in the thickness direction, the absorbent article has a welded joint where the sheet member and the adjacent member are welded and joined in the thickness direction, and when the absorbent article is viewed in the thickness direction, the portion where the low basis weight portion and the non-skin side layer overlap overlaps at least a portion of the welded joint.

[0038] According to the sheet member of aspect 14, it is possible to reduce the risk of a decrease in the joining strength of the welded joint.

[0039] (Aspect 15) The sheet member of any one of Aspects 1 to 14, wherein the non-skin side fibers are thermoplastic fibers, the absorbent article has a joint where both left and right side portions of a pair of waistband portions are welded together, the sheet member is used in a position overlapping at least a portion of the joint when viewed in the thickness direction, and the joint overlaps at least a portion of the portion where the low basis weight portion and the non-skin side layer overlap.

[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 joints at both sides of the pair of waistband portions in the left-right direction.

[0041] (Aspect 16) The sheet member of Aspect 15, wherein the pair of waistband portions have a plurality of intermittent joints in the up-down direction, and the distance between the centers of adjacent joints in the up-down direction is longer than the distance between the centers of the low basis weight portions.

[0042] According to the sheet member of aspect 16, it is possible to facilitate the transfer of moisture absorbed by the skin-side layer from the low basis weight portion to the non-skin-side layer, while reducing the risk of a decrease in the bonding strength of the joints at both sides of the pair of waistband portions in the left-right direction.

[0043] (Aspect 17) The sheet member of Aspect 15 or 16, characterized in that the joints are provided intermittently in the up-down direction, the sheet member has a vertical direction and a horizontal direction perpendicular to the thickness direction, and the area of ​​a region defined by straight lines connecting the centers of four low basis weight sections adjacent to each other in the vertical direction and the horizontal direction is smaller than the maximum area of ​​the joints.

[0044] According to the sheet member of aspect 17, it is easier to provide a wider area where the low basis weight section and the joint overlap in the thickness direction than when the area defined by the straight lines connecting the centers of four adjacent low basis weight sections in the vertical and horizontal directions is made larger than the maximum area of ​​the joint, making it easier to increase the bonding strength at the joint.

[0045] (Aspect 18) The sheet member of Aspect 15 or 16, characterized in that the joints are provided intermittently in the up-down direction, the sheet member has a vertical direction and a horizontal direction perpendicular to the thickness direction, and the area of ​​the region defined by straight lines connecting the centers of four low basis weight sections adjacent to each other in the vertical direction and the horizontal direction is larger than the minimum area of ​​the joints.

[0046] According to the sheet member of aspect 18, the area where the low basis weight sections and the joints overlap in the thickness direction is larger than when the area of ​​the region defined by the straight lines connecting the centers of four adjacent low basis weight sections in the vertical and horizontal directions is made larger than the minimum area of ​​the joints, thereby reducing the risk of the joint strength becoming excessively strong and making it difficult to separate the ventral waistline section and the dorsal waistline section after use of the absorbent article.

[0047] (Aspect 19) An absorbent article having an absorbent body and a sheet member provided on the skin side of the absorbent body, wherein the sheet member has a skin-side layer that can come into contact with 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 that are base fibers of the skin-side layer is higher than the hydrophilicity of the non-skin-side fibers that are base fibers of the non-skin-side layer, wherein the skin-side layer has a predetermined basis weight section including the skin-side fibers of a predetermined basis weight and a low basis weight section in which the basis weight of the skin-side fibers is lower than that of the predetermined basis weight section, and wherein, when viewed in the thickness direction, the absorbent article has a portion where the predetermined basis weight section and the non-skin-side layer overlap and a portion where the low basis weight section and the non-skin-side layer overlap.

[0048] According to the absorbent article of aspect 19, the highly hydrophilic skin-side layer improves the absorbency and feel of the sheet member, while also facilitating the transfer of moisture absorbed by the skin-side layer from the low basis weight portion to the non-skin side of the sheet member, thereby reducing the risk of moisture absorbed by the sheet member remaining in contact with the wearer's skin and reducing discomfort and adverse effects on the wearer's skin.

[0049] ===Embodiment=== Hereinafter, a sheet member for an absorbent article according to this embodiment will be described using a pants-type disposable diaper 1 for adults (hereinafter simply referred to as "diaper 1") as an example of an absorbent article, and a sweat-absorbing sheet (sheet portions 25, 35) of the waist portion 20, 30 of the diaper 1 as an example of a sheet member. However, the absorbent article according to this embodiment is not limited to the above, and can also be applied, for example, to pants-type disposable diapers for infants, shorts-type napkins, tape-type disposable diapers, etc. Furthermore, the sheet member may be any member that can contact the skin side of each absorbent article, regardless of whether it is a sweat-absorbing sheet.

[0050] <Basic Structure of Pants-Type Disposable Diaper 1> Fig. 1 is a schematic perspective view of the diaper 1 as seen from the ventral side. Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and stretched state as seen from the wearer's skin side. Fig. 3 is a schematic cross-sectional view taken along line A-A in Fig. 2.

[0051] The "unfolded state" of the diaper 1 refers to a state in which the diaper 1 is unfolded on a plane by separating the ventral waistband 20 (described later) and the dorsal waistband 30 (described later) from the pants-type diaper 1 in Fig. 1 at the side seams SS (described later) on both the left and right sides, and opening the diaper 1 vertically. The "stretched state" of the diaper 1 refers to a state in which the product (diaper 1) is stretched without wrinkles, specifically, a state in which the dimensions of each component (e.g., the absorbent main body 10, the ventral waistband 20, etc.) constituting the diaper 1 are stretched to the extent that they match or are close to the dimensions of the individual components.

[0052] When worn in a pants-like state as shown in FIG. 1 , the diaper 1 has intersecting vertical, horizontal, and front-to-back directions, and has a waist opening BH and a pair of leg openings LH. In the vertical direction, the waist opening BH side is the upper side, and the side facing the wearer's crotch is the lower side. In the front-to-back direction, the side facing the wearer's belly side is the front side, and the side facing the wearer's back side is the back side. In the unfolded and stretched state shown in FIG. 2 , the diaper 1 has three mutually intersecting directions: a longitudinal direction, a lateral direction, and a thickness direction (a direction passing through the paper in FIG. 2 ). The longitudinal direction is aligned with the above-mentioned vertical direction. One longitudinal side corresponds to the ventral side (front side), and the other longitudinal side corresponds to the back side (rear side). The diaper 1 also has a thickness direction in which materials are layered, as shown in FIG. 3 . The side in contact with the wearer in the thickness direction is the skin side, and the opposite side is the non-skin side.

[0053] The diaper 1 includes an absorbent body 10 and an outer casing 18. The outer casing 18 includes a pair of waistband sections 20, 30 and a crotch section 40 located between the wearer's legs. The outer casing 18 is joined to the non-skin side of the absorbent body 10 with an adhesive or the like. Of the pair of waistband sections 20, 30, the one located on the ventral side (front side) of the wearer is also referred to as the ventral waistband section 20, and the one located on the dorsal side (rear side) is also referred to as the dorsal waistband section 30. The ventral waistband section 20 and the dorsal waistband section 30 are joined on both lateral sides by a pair of side joining sections SS. Examples of joining methods using the side joining sections SS include thermal welding, ultrasonic welding, and adhesive joining.

[0054] As shown in FIG. 3 , the absorbent body 10 includes an absorbent core (absorbent body) 11, a liquid-permeable top sheet 12 disposed closer to the skin than the absorbent core 11, a liquid-impermeable back sheet 13 disposed closer to the skin than the absorbent core 11, and an exterior sheet 14. The absorbent core 11 may be any material capable of absorbing and retaining excrement, such as a liquid-absorbent material such as pulp fiber or superabsorbent polymer (SAP) molded into a predetermined shape. The absorbent core 11 may also be covered with a liquid-permeable sheet such as tissue paper or a nonwoven fabric. The top sheet 12 is formed of, for example, a nonwoven fabric such as an air-through nonwoven fabric or a spunbond nonwoven fabric. The back sheet 13 is, for example, a liquid-impermeable and breathable film such as polyethylene or polypropylene. The exterior sheet 14 is formed of, for example, the same nonwoven fabric as the top sheet 12.

[0055] 2, a plurality of leg-hole elastic members 15 (e.g., rubber threads) that stretch along the longitudinal direction of the absorbent body 10 are provided on both lateral sides of the absorbent body 10. Furthermore, by providing, for example, an elastic member that stretches in the longitudinal direction on the inner side of the leg-hole elastic members 15 in the lateral direction, a leakage prevention wall that can stand up against the skin side may be provided.

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

[0057] The inner layer sheet 21 is disposed from the ventral waistline portion 20 through the crotch portion 40 to the back waistline portion 30 (FIG. 3). The width (length in the left-right direction) of the inner layer sheet 21 in the ventral waistline portion 20 and the back waistline portion 30 is greater than the width (length in the left-right direction) of the inner layer sheet 21 in the crotch portion 40 (FIG. 2). The inner layer sheet 21 may be an air-through nonwoven fabric, a spunbond nonwoven fabric, an SMS nonwoven fabric (spunbond-meltblown-spunbond nonwoven fabric), a waterproof film, or the like.

[0058] 2 and 3, the ventral outer layer sheet 22 is located closer to the skin than the inner layer sheet 21, and the ventral outer layer sheet 22 and the inner layer sheet 21 together form the ventral waistline portion 20. The outer end (upper end) of the ventral outer layer sheet 22 in the longitudinal direction is folded back toward the skin. The folded-back portion 22r of the ventral outer layer sheet 22 encloses one end (outer end) of the inner layer sheet 21 in the longitudinal direction. However, the outer end (upper end) of the ventral outer layer sheet 22 in the longitudinal direction may not be folded back.

[0059] 2 and 3, the back outer sheet 32 ​​is disposed closer to the skin than the inner sheet 21, and the back outer sheet 32 ​​and the inner sheet 21 together form the back waistband portion 30. The outer end (upper end) of the back outer sheet 32 ​​in the longitudinal direction is folded back toward the skin. The folded-back portion 32r of the back outer sheet 32 ​​encloses the other end (outer end) of the inner sheet 21 in the longitudinal direction. The outer end (upper end) of the back outer sheet 32 ​​in the longitudinal direction may not be folded back.

[0060] The ventral outer layer sheet 22 and the dorsal outer layer sheet 32 ​​may be made of an air-through nonwoven fabric, a spunbond nonwoven fabric, an SMS nonwoven fabric (spunbond meltblown spunbond nonwoven fabric), or the like.

[0061] The ventral waist portion 20 and the back waist portion 30 each have waist elastic members 23, 33 that are stretchable in the left-right direction. The multiple waist elastic members 23, 33 are spaced apart in the vertical direction between the inner layer sheet 21 and the ventral outer layer sheet 22, and between the inner layer sheet 21 and the back outer layer sheet 32, and are fixed in a stretched state in the left-right direction (see Figures 2 and 3). Thus, the ventral waist portion 20 and the back waist portion 30 stretch in the left-right direction to fit the waist of the wearer. Examples of the waist elastic members 23, 33 include thread-like stretchable members such as rubber threads and elongated stretchable sheets.

[0062] In this embodiment, rear leg elastic members 34 are provided in the back waistband 30 between the inner sheet 21 and the back outer sheet 32. The rear leg elastic members 34 may be, for example, a plurality of rubber threads or a stretchable elastic sheet in the shape of a strip. The rear leg elastic members 34 are joined and fixed in a stretched state with an adhesive such as a hot melt adhesive.

[0063] In this embodiment, sheet portions 25, 35 that easily absorb the wearer's sweat are provided in predetermined regions of the ventral waistline portion 20 and the dorsal waistline portion 30 that are closest to the skin (hatched areas in Fig. 2 ). The sheet portions 25, 35 are arranged closer to the skin than the absorbent main body 10 (absorbent core 11), are shorter in the vertical direction than the inner layer sheet 21 and the ventral and dorsal outer layer sheets 22, 32, etc., and are strip-shaped sheet members arranged to cover the longitudinal ends of the absorbent main body 10. Details of the sheet portions 25, 35 will be described later.

[0064] The above describes the basic configuration of the diaper 1, but the above configuration of the diaper 1 is merely an example and is not intended to be limiting. For example, the diaper 1 of this embodiment is configured with an outer body 18 having three sections: a ventral waist section 20, a dorsal waist section 30, and a crotch section 40 connecting them. However, the present invention is not limited to this. For example, the diaper may have a configuration in which the ventral waist section 20 and the dorsal waist section 30 are formed from separate members, and the non-skin side of the absorbent main body 10 is exposed in the crotch section. Alternatively, the diaper may have an outer body member formed from a single member that is continuous from the ventral waist section 20 to the dorsal waist section 30.

[0065] <Regarding seat portions 25, 35> The specific configurations of seat portions 25 and 35 according to this embodiment will be described below. Note that in this embodiment, the seat portion 25 provided in the ventral waistline portion 20 and the seat portion 35 provided in the dorsal waistline portion 30 have substantially the same configuration. Therefore, in the following description, content common to both seat portion 25 and seat portion 35 will be described only for seat portion 25 as a representative of both. Regarding seat portion 35, reference numerals of components corresponding to seat portion 25 will be indicated in parentheses as necessary, and a specific description will be omitted.

[0066] Fig. 4 is a schematic cross-sectional view of the sheet portion 25. Fig. 5A is a diagram illustrating the sheet portion 25 as viewed from the skin side. Fig. 5B is an enlarged schematic view of a portion of Fig. 4A. As described above, in this embodiment, the sheet portion 25 constitutes part of the surface of the ventral waistline portion 20 that comes into contact with the wearer's skin (Fig. 3). As shown in Fig. 4, the sheet portion 25 has a skin-side layer 25a arranged to come into contact with the wearer's skin, and a non-skin-side layer 25b located on the non-skin side of the skin-side layer 25a in the thickness direction.

[0067] The skin-side layer 25a is a layer whose base fiber is cotton, a hydrophilic fiber. The term "base material" as used herein refers to a material that accounts for more than 50% of the mass of each layer (skin-side layer 25a, non-skin-side layer 25b). The non-skin-side fiber, which is the base fiber of the non-skin-side layer 25b, may be polyester fiber, polypropylene fiber, polyethylene fiber, polyurethane fiber, or a composite fiber thereof. These fibers may be either hydrophilically treated or not. Hereinafter, the base fiber of the skin-side layer 25a will also be referred to as the "skin-side fiber," and the base fiber of the non-skin-side layer 25b will also be referred to as the "non-skin-side fiber."

[0068] In the sheet member constituting the sheet portion 25 of this 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). The skin side layer 25a and the non-skin side layer 25b can be integrated by entanglement using a known hydroentangling method, such as a water jet.

[0069] In this embodiment, the non-skin side fibers 25bs of the non-skin side layer 25b are themselves hydrophobic fibers, but the non-skin side fibers 25bs are pre-coated with a hydrophilizing agent and then entangled with the skin side fibers 25as using a hydroentangling method to form a sheet. During this entanglement process, the hydrophilizing agent applied to the surface of the base fiber 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 this embodiment include fibers from which the hydrophilizing agent has been completely removed and which have retained some of the hydrophilizing agent, and fibers from which the hydrophilizing agent has been completely removed and which have retained some of the hydrophilizing agent.

[0070] The sheet member 25 can be provided on the skin side of the diaper 1, and the thickness direction of the sheet member 25 is aligned with the thickness direction of the diaper 1. The longitudinal and lateral directions of the sheet member 25 may or may not be aligned with the up-down and left-right directions, respectively, of the diaper 1. As long as the plane of the sheet member 25 is aligned with the plane of the diaper 1, the sheet member 25 can be used in any direction.

[0071] Since the sheet portion 25 is a member that contacts the wearer's skin when worn, it is preferable that it feel pleasant to the touch. Therefore, it is preferable that the member constituting the sheet portion 25 be made of a fiber that feels pleasant to the touch. Examples of fibers that are known to feel pleasant to the touch include hydrophilic fibers such as cotton and rayon. However, the more hydrophilic a fiber is, the more easily the fiber itself absorbs moisture and retains the absorbed moisture. This can cause the sheet portion 25 to make the diaper 1 damp, or cause moisture to continuously adhere to the wearer's skin, which can cause discomfort to the wearer's skin or lead to adverse effects such as rough skin.

[0072] In contrast, the sheet member 25 of the diaper 1, which is capable of contacting the wearer's skin, includes a skin-side layer 25a and a non-skin-side layer 25b disposed on the non-skin-side side of the skin-side layer 25a. The skin-side fibers 25as of the skin-side layer 25a have a higher hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b. The skin-side layer 25a also includes a predetermined basis weight portion 25aP having skin-side fibers 25as of a predetermined basis weight, and a low basis weight portion 25aL having a lower basis weight of the skin-side fibers 25as than the predetermined basis weight portion 25aP. As shown in Figures 4 and 5, when viewed in the thickness direction of the sheet member 25 (diaper 1), the predetermined basis weight portion 25aP overlaps with the non-skin-side layer 25b in a region where the low basis weight portion 25aL overlaps with the non-skin-side layer 25b.

[0073] As described above, the more hydrophilic the fibers in the sheet portion 25 are, the more likely they are to have improved absorbency and softness against the skin. Hydrophilic fibers, such as cotton and rayon, are particularly soft and rounded, which means they are less irritating to the skin and more comfortable against the skin. Therefore, the skin-side layer 25a, which includes the highly hydrophilic skin-side fibers 25as, is positioned closer to the skin than the non-skin-side layer 25b, which has a lower hydrophilicity than the skin-side fibers 25as. When viewed in the thickness direction of the sheet portion 25, the predetermined basis weight portion 25aP of the skin-side layer 25a and the non-skin-side layer 25b overlap. This allows the predetermined basis weight portion 25aP of the sheet portion 25 to contact the wearer's skin, thereby improving the absorbency and softness of the sheet portion 25 (diaper 1) when worn. On the other hand, since the sheet portion 25 has a low basis weight portion 25aL in which the skin-side fibers have a low basis weight and has a portion where the low basis weight portion 25aL and the non-skin-side layer 25b overlap when viewed in the thickness direction of the sheet portion 25, when worn, 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 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 in which the skin-side fibers 25as have a low basis weight, and more likely to transfer moisture from the low basis weight portion 25aL to the non-skin-side layer 25b. Furthermore, even when the skin-side layer 25a absorbs moisture such as sweat when worn, the portion of the skin-side layer 25a in contact with the wearer's skin can be made smaller, thereby reducing the risk of the wearer's skin feeling sticky even when the skin-side fibers 25as of the skin-side layer 25a absorb moisture. This reduces the risk of excessive moisture retention in the skin-side layer 25a, which in turn reduces the risk of the diaper 1 becoming damp or causing adverse effects such as rough skin on the wearer. Thus, by providing the diaper 1 with this sheet portion 25, discomfort and adverse effects on the wearer's skin can be reduced.

[0074] The "low basis weight portion 25aL" may be any portion having a lower basis weight of the skin-side fibers 25as than the predetermined basis weight portion 25aP, and may refer to a case where the low basis weight portion 25aL has skin-side fibers 25as or a case where the low basis weight portion 25aL does not have skin-side fibers 25as. In either case, the low basis weight portion 25aL is preferably a portion recessed away from the skin side from the predetermined basis weight portion 25aP. By recessing the low basis weight portion 25aL away from the skin side from the predetermined basis weight portion 25aP, when worn, the predetermined basis weight portion 25aP becomes a portion of the skin-side layer 25a of the sheet member 25 that is likely to come into contact with the wearer's skin, improving the feel against the wearer's skin, while the low basis weight portion 25aL becomes a portion that is less likely to come into contact with the wearer's skin. This makes it easier for moisture and humidity such as sweat to move to the non-skin side layer 25b via the low basis weight portion 25aL where there is less skin side fiber 25as, and even if the skin side layer 25a absorbs moisture such as sweat when worn, the portion of the skin side layer 25a that comes into contact with the wearer's skin is made smaller, thereby reducing the risk of the wearer's skin feeling sticky even if the skin side fiber 25as of the skin side layer 25a absorbs moisture.

[0075] In this embodiment, the low basis weight portion 25aL is a portion where the skin-side fibers 25as are almost absent and where the basis weight of the skin-side fibers 25as is zero. Put simply, this is a portion where the skin-side layer 25a is missing in the thickness direction. Therefore, when the sheet member 25 is viewed from the skin side, the non-skin-side layer 25b (non-skin-side fibers 25bs) is visible through the low basis weight portion 25aL. Because the skin-side fibers 25as are soft and have some fluidity, the portion where the basis weight of the skin-side fibers 25as is zero does not mean that there are no skin-side fibers 25as at all (zero), but may be a portion where only a few skin-side fibers 25as are present in the low basis weight portion 25aL.

[0076] In contrast to the skin-side layer 25a, the non-skin-side layer 25b is preferably 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 overlapping portion between the low basis weight portion 25aL and the non-skin-side layer 25b is not blocked by the skin-side fibers 25as when viewed from the skin side, and the non-skin-side layer 25b can be directly seen. Note that the non-skin-side layer 25b is formed by entanglement of fibers such as the non-skin-side fibers 25bs, and therefore has gaps between the fibers. Because these gaps between the fibers are very small, it can be said that the non-skin-side layer 25b is provided over the entire area of ​​the sheet portion 25. In other words, the non-skin-side layer 25b is a layer that does not have any intentionally provided openings such as through-holes.

[0077] In the present embodiment, when the basis weight of the skin-side fibers 25as in the low basis weight portion 25aL is zero, the predetermined basis weight portion 25aP of the skin-side layer 25a of the sheet portion 25 is likely to come into contact with the wearer's skin while the low basis weight portion 25aL is unlikely to come into contact with the wearer's skin. As a result, moisture such as sweat is less likely to be retained by the skin-side fibers 25as in the low basis weight portion 25aL and is more likely to be absorbed by the non-skin-side layer 25b. This improves the feel against the wearer's skin due to the predetermined basis weight portion 25aP coming into contact with the wearer's skin, while also promoting moisture absorption in the non-skin-side layer 25b, thereby reducing the risk of moisture being continuously retained in the skin-side layer 25a.

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

[0079] <Contact Angle Measurement Method> (1) First, cotton fibers and non-skin-side fibers were removed from designated locations on each layer. The removed fibers were cut to 10 mm lengths, and five samples of each fiber were prepared. (2) The measurement device used was an automatic micro-contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd., and the measurement environment was a room temperature of 22±2°C and a humidity of 65±2% RH. (3) The sample was placed on the measurement device, and 20 picoliters of distilled water (microdroplets) were dropped onto the surface of the fiber from the inkjet head installed on the device. The appearance of the microdroplets was recorded over time. (4) Images taken immediately after the microdroplets adhered to the fiber surface were analyzed, and the contact angle of the microdroplets relative to the fiber surface was calculated. (5) Contact angles were measured at 20 different locations per fiber. The contact angles of five samples were measured, and the average value of the 100 measurements was used as the contact angle. If the layer (sheet) to be measured is bonded to another member by adhesive, fusion, or the like, the adhesive strength of the bonded portion should be weakened by a cooling method such as cold spray to the extent that the contact angle of the fibers is not affected before removal.

[0080] It is preferable that the sheet portion 25 has a portion where the skin-side fibers 25as and the non-skin-side fibers 25bs are entangled. The sheet portion 25 is formed by entanglement of the fibers, which improves the flexibility of the sheet portion 25 and the feel of the diaper 1 using this sheet 25. The skin-side fibers 25as and the non-skin-side fibers 25bs can be entangled by a known method such as water jet or air.

[0081] Furthermore, it is preferable that the sheet portion 25 is not provided with an adhesive. By not providing the sheet portion 25 with an adhesive, the risk of the sheet portion 25 becoming hard is reduced, and the risk of the diaper 1 using the sheet portion 25 becoming less comfortable against the skin is reduced. Furthermore, the risk of the adhesive interfering with moisture absorption is reduced, and the risk of moisture such as sweat remaining on the surface of the sheet portion 25 is reduced, thereby reducing the risk of discomfort or adverse effects on the wearer's skin. While it is preferable that the sheet portion 25 itself is not provided with an adhesive, an adhesive may be used to secure the sheet portion 25 to a member or other component adjacent to the sheet portion 25 in the diaper 1. The sheet portion 25 may be secured to a predetermined position on the diaper 1 using an adhesive, or the adhesive used for this securing may be impregnated into the sheet portion 25.

[0082] Similarly, it is preferable that the sheet portion 25 does not have any portions that are compressed in the thickness direction of the sheet portion 25. Compressed portions provided in the sheet portion 25 can reduce the risk of the sheet portion 25 becoming hard, thereby reducing the risk of the diaper 1 using the sheet portion 25 becoming soft to the touch. Note that the "portions compressed in the thickness direction" of the sheet portion 25 refer to locally compressed portions of the sheet portion 25, and do not include portions where pressure is applied across the entire area of ​​the sheet portion 25 during the formation of the sheet portion 25.

[0083] The skin-side fibers 25as in the skin-side layer 25a of the sheet portion 25 are preferably cotton fibers. Cotton fibers are soft, have a rounded fiber shape, and are highly absorbent. Therefore, by using cotton fibers for the skin-side fibers 25as of the skin-side layer 25a that contacts the wearer's skin, the fabric feels comfortable against the wearer's skin and can reduce irritation to the wearer's skin while wearing the sheet.

[0084] The fibers forming the skin side layer 25a need only comprise the skin side fibers 25as, which are base fibers, in a weight ratio of greater than 50%, and may also contain fibers other than the skin side fibers 25as (e.g., hydrophobic fibers). Examples of the skin side fibers 25as include cellulosic fibers such as cotton and rayon, and thermoplastic resin fibers that have been hydrophilically treated. The skin side fibers 25as, which are base fibers of the skin side layer 25a, may be one type of fiber or multiple types of fibers. In the present embodiment, the skin side layer 25a is made up of 100% cotton fibers and is formed almost exclusively of cotton fibers (skin side fibers 25as).

[0085] Since the sheet portion 25 is formed into a sheet shape by entangling 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 some of the fibers of the non-skin side layer 25b (non-skin side fibers 25bs) are disposed in the skin side layer 25a. It is preferable that at least some of the skin side fibers 25as be present on the non-skin side of the non-skin side layer 25b. This further strengthens the entanglement between the skin side layer 25a and the non-skin side layer 25b, reducing the risk of separation between the skin side layer 25a and the non-skin side layer 25b.

[0086] The fibers forming the non-skin side layer 25b need only comprise the non-skin side fibers 25bs, which are base fibers, in a weight ratio greater than 50%, and may also contain fibers other than the non-skin side fibers 25bs (e.g., hydrophilic fibers). Examples of the non-skin side fibers 25bs include thermoplastic resin fibers. The non-skin side fibers 25bs, which are base fibers of the non-skin side layer 25b, may be one type of fiber or multiple types of fibers. In this embodiment, the non-skin side layer 25b is made up of 100% composite fibers having a sheath-core structure of polypropylene (PP) and polyethylene (PE), and the non-skin side layer 25b is formed almost entirely of composite fibers (non-skin side fibers 25bs) of PP and PE. Since the sheet portion 25 is formed into a sheet by intertwining the fibers of the skin side layer 25a (skin side fibers 25as) with the fibers of the non-skin side layer 25b (non-skin side fibers 25bs), at least a portion of the fibers of the skin side layer 25a (skin side fibers 25as) are arranged in the non-skin side layer 25b.

[0087] In addition, in the skin side layer 25a of the sheet portion 25, the basis weight of the skin side fibers 25as in the low basis weight portion 25aL is lower than the basis weight of the skin side fibers 25as in the specified basis weight portion 25aP, and it is more preferable that the basis weight of all fibers present in the low basis weight portion 25aL of the skin side layer 25a, not limited to the skin side fibers 25as, is lower than the basis weight of all fibers present in the specified basis weight portion 25aP.

[0088] It is also preferable that at least a portion of the non-skin-side fibers 25bs be present on the skin-side surface of the skin-side layer 25a. Because 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 transfer moisture, such as sweat, toward the non-skin-side layer 25b rather than absorbing it themselves. This reduces the risk of moisture absorbed by the sheet portion 25 remaining in contact with the wearer's skin, thereby reducing discomfort and adverse effects on the wearer's skin.

[0089] As described above, the skin-side sheet 25 is formed into a sheet shape by entangling 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. Therefore, in the skin-side layer 25a, the number of non-skin-side fibers 25bs entangled with the skin-side fibers 25as in the specified basis weight portion 25aP is preferably greater than the number of non-skin-side fibers 25bs entangled with the skin-side fibers 25as in the low basis weight portion 25aL. This facilitates the migration of moisture from the skin-side side of the specified basis weight portion 25aP to the non-skin-side side. This reduces the risk of moisture absorbed by the sheet portion 25 remaining in contact with the wearer's skin, thereby reducing discomfort and adverse effects on the wearer's skin.

[0090] In the sheet portion 25, the density of the skin-side fibers 25as in the low-basis-weight portion 25aL is preferably lower than the density of the skin-side fibers 25as in the specified-basis-weight portion 25aP. When worn, the overlapping portion of the specified-basis-weight portion 25aP and the non-skin-side layer 25b in the thickness direction absorbs moisture, such as sweat, from the wearer's skin. This facilitates evaporation of the moisture absorbed by the specified-basis-weight portion 25aP from the low-basis-weight portion 25aL, which has a low basis-weight of the skin-side fibers 25as, and facilitates moisture transfer from the low-basis-weight portion 25aL to the non-skin-side layer 25b. This reduces the risk of excessive moisture retention in the skin-side layer 25a, thereby reducing the risk of the diaper 1 becoming damp or causing adverse effects such as rough skin. This also reduces discomfort and adverse effects on the wearer's skin when wearing the diaper 1.

[0091] 5A and 5B , the sheet portion 25 preferably has predetermined basis weight portions 25aP and low basis weight portions 25aL alternately arranged in the up-down direction, and the predetermined basis weight portions 25aP and low basis weight portions 25aL alternately arranged in the left-right direction. In the diaper 1 of this embodiment, the up-down direction of the diaper 1 corresponds to the longitudinal direction of the sheet portion 25, and the left-right direction of the diaper 1 corresponds to the lateral direction of the sheet portion 25. The non-skinside layer 25b is provided over the entire area of ​​the sheet portion 25 in the up-down and left-right directions, and the skinside layer 25a is provided in a staggered pattern closer to the skin than the non-skinside layer 25b. As a result, when worn, the overlapping portions of the predetermined basis weight portions 25aP and the non-skinside layer 25b in the thickness direction absorb moisture such as sweat from the wearer's skin, and the moisture absorbed by the predetermined basis weight portions 25aP is easily evaporated from the low basis weight portions 25aL, which have a low basis weight of the skin-side fibers 25as, and moisture transfer from the low basis weight portions 25aL to the non-skinside layer 25b. This reduces the risk of excessive moisture retention in the skin-side layer 25a, thereby reducing the risk of the diaper 1 becoming stuffy or causing adverse effects such as rough skin. Furthermore, by alternately arranging the predetermined basis weight portions 25aP and the low basis weight portions 25aL in the vertical direction and the horizontal direction, discomfort and adverse effects on the wearer's skin caused by wearing the diaper 1 can be reduced over a wide area of ​​the sheet portion 25. The arrangement of the predetermined basis weight portions 25aP and the low basis weight portions 25aL in the sheet portion 25 is not limited to this. It is sufficient that the predetermined basis weight portions 25aP and the low basis weight portions 25aL are alternately arranged in the vertical direction and alternately arranged in the horizontal direction, and they may be arranged in a grid pattern or randomly, for example.

[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 this is not limited thereto. For example, the sheet portion 25 may have a sheet compressed portion (not shown) in which parts of the skin side layer 25a and the non-skin side layer 25b are compressed in the thickness direction. In other words, the sheet portion 25 itself may be compressed. This reduces the risk of separation of the skin side layer 25a and the non-skin side layer 25b.

[0093] Alternatively, the sheet portion 25 may have a portion where only the skin side layer 25 a or only the non-skin side layer 25 b is compressed. For example, in the manufacturing process of the sheet portion 25, the non-skin side fibers 25 bs may be compressed together in the thickness direction to form a layer, and then the non-skin side fibers 25 bs and the skin side fibers 25 as may be entangled to form the sheet portion 25.

[0094] Alternatively, 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 together. In other words, the sheet portion 25 may have a portion where the sheet portion 25 itself is melted. This reduces the risk of separation between the skin side layer 25a and the non-skin side layer 25b.

[0095] In addition, the sheet portion 25 may be configured such that the skin side fibers 25as and the non-skin side fibers 25bs are intertwined, and further include a sheet compression portion or a portion where the skin side fibers 25as and the non-skin side fibers 25bs are melt-bonded.

[0096] Furthermore, the diaper 1 preferably includes a hydrophilic member comprising fibers that are more hydrophilic than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet member 25, and more preferably, the sheet member 25 is disposed on the skin-side side of the hydrophilic member in the thickness direction of the diaper 1 and in a position that overlaps the hydrophilic member when viewed in the thickness direction of the diaper 1. Specifically, in this embodiment, as shown in Fig. 3, the diaper 1 includes a top sheet 12 comprising fibers that are more hydrophilic than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet member 25, and the top sheet 12 corresponds to the hydrophilic member. The fibers of the top sheet 12 or the top sheet 2 itself have been subjected to a hydrophilic treatment by a well-known method, so that the fibers of the top sheet 12 are more hydrophilic than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet member 25. The diaper 1 includes a sheet portion 25 positioned closer to the skin than the top sheet 12 and overlapping the top sheet in the thickness direction of the diaper 1. This facilitates the transfer of moisture, such as sweat, absorbed from the sheet portion 25 to the non-skin side when the diaper 1 is worn, thereby reducing discomfort and adverse effects on the wearer's skin caused by continued moisture adhering to the wearer's skin. The hydrophilic member in the diaper 1 is not limited to the top sheet 12, but may be any member that includes fibers with 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 in the thickness direction. The absorber 11, the inner layer sheet 21, etc. may also be hydrophilic. The hydrophilicity of the non-skin-side fibers 25bs and the fibers of the top sheet 12 can be compared using the hydrophilicity measurement method described above.

[0097] Alternatively, the diaper 1 may have a non-hydrophilic member comprising fibers having a lower hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b of the sheet member 25, and the sheet member 25 may be provided on the skin side of the non-hydrophilic member in the thickness direction of the diaper 1, at a position overlapping the non-hydrophilic member when viewed in the thickness direction of the diaper 1. For example, in the diaper 1, the top sheet 12 provided on the non-skin side of the non-skin-side layer 25b may comprise fibers having 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 member 25 when viewed in the thickness direction. Although the top sheet 12 of this embodiment has been subjected to a hydrophilization treatment, the top sheet 12 as a non-hydrophilic member may comprise fibers having a lower hydrophilicity than the non-skin-side fibers 25bs of the non-skin-side layer 25b. The non-hydrophilic member provided on the non-skin-side side of the non-skin-side layer 25b prevents moisture absorbed by the sheet portion 25 from migrating from the non-skin-side layer 25b toward the non-hydrophilic member during wear of the diaper 1, allowing the non-skin-side layer 25b to retain moisture more easily. This reduces the risk of moisture absorbed from the sheet portion 25 penetrating the non-skin-side side of the diaper 1 and causing the non-skin-side side of the diaper 1 to become sticky. Furthermore, because the low-basis weight portion 25aL has a low basis weight of skin-side fibers 25as, the low-basis weight portion 25aL is thinner than the specified-basis weight portion 25aP and is therefore more likely to sink toward the non-skin side than the specified-basis weight portion 25aP. This reduces the risk of moisture remaining on the wearer's skin in the area overlapping the low-basis weight portion 25aL in the thickness direction. This reduces discomfort on both the skin-side and non-skin-side sides of the diaper 1 during wear.

[0098] Preferably, the diaper 1 has a stretchable elastic member, and the sheet portion 25 is provided at a position overlapping at least a portion of the stretchable member in the thickness direction of the diaper 1 in the unfolded and stretched state. As shown in Fig. 3 , the diaper 1 of this embodiment has waist elastic members 23 stretchable in the left-right direction, and the sheet portion 25 is provided at a position overlapping at least a portion of the waist elastic members 23 in the thickness direction of the diaper 1 in the unfolded and stretched state. Contraction of the waist elastic members 23 allows wrinkles to be formed in the ventral waist portion 20 and the sheet portion 25. Therefore, the sheet portion 25 improves the feel of the diaper 1 against the skin, while the wrinkles formed in at least a portion of the sheet portion 25 improve the breathability of the sheet portion 25, thereby reducing stuffiness and irritation to the wearer's skin when the diaper 1 is worn.

[0099] As described above, the ventral waistline portion 20 and the back waistline portion 30 are joined at a pair of side seams (seams) SS on both lateral sides. Figure 6 is an enlarged schematic view of portion X in Figure 2 . In this embodiment, the inner layer sheet 21 and the ventral outer layer sheet 22 of the ventral waistline portion 20 are formed of nonwoven fabrics made of thermoplastic resin fibers, and therefore the side seams SS are composed of a plurality of seams 70 welded together. In Figure 6 , the seams 70 are indicated by hatched areas slanting downward to the left. In such a case, it is preferable that the non-skinside fibers 25bs of the sheet portion 25 be thermoplastic fibers. As shown in Figures 2 and 6 , the sheet portion 25 is positioned so as to overlap at least a portion of the side seams SS when viewed in the thickness direction of the diaper 1 (sheet portion 25), and the side seams SS preferably overlap at least a portion of the overlapping portion between the low basis weight portion 25aL and the non-skinside layer 25b. This reduces the risk of a decrease in the joining strength of the side joints SS on both sides of the pair of waistbands 20, 30 in the left-right direction.

[0100] Specifically, when the garment is in a pants-type configuration, the side joint SS is formed by stacking 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 ​​in that order from front to back in the front-to-back direction, and a welding joint 70 is formed by applying ultrasound, pressure, heat, etc. (see Figures 2 and 3). In the diaper 1, sheet portions 25, 35 are provided on the side closest to the skin of the waist portions 20, 30 and closer to the skin than the absorbent main body 10 (absorbent body 11), and the sheet portions 25, 35 are provided between the inner layer sheet 21 of the ventral waist portion 20 and the inner layer sheet 21 of the dorsal waist portion 30, and the sheet portions 25, 35 are superimposed on the ventral outer layer sheet 22, the inner layer sheet 21 of the ventral waist portion 20, the inner layer sheet 21 of the dorsal waist portion 30, and the dorsal outer layer sheet 32, and a joint 70 is formed by welding the sheet portions 25, 35 together in a state where all of these sheets overlap in the thickness direction, thereby forming a side joint SS.

[0101] The skin-side layer 25a of the sheet portion 25 preferably uses highly hydrophilic fibers such as cotton or rayon as the skin-side fibers 25as, but these fibers are difficult to melt even when subjected to ultrasonic waves or heat, and therefore tend to interfere with welding and may reduce the bonding strength of the side joint SS. However, even if the sheet portion 25 of this embodiment is provided at a position overlapping the side joint SS in the thickness direction, the sheet portion 25 has a predetermined basis weight portion 25aP and a low basis weight portion 25aL, and the side joint SS overlaps at least a portion of the portion where the low basis weight portion 25aL overlaps with the non-skin-side layer 25b in the thickness direction of the diaper 1. As a result, the low basis weight portion 25aL has a small amount of skin side fibers 25as, and the thermoplastic fibers that are the non-skin side fibers 25bs of the non-skin side layer 25b are more likely to melt with the fibers of the inner layer sheet 21, etc., thereby reducing the risk of interference with melt-bonding due to the presence of the sheet portion 25 and reducing a decrease in bond strength at the side bond region SS. In particular, in this embodiment, the basis weight of the skin side fibers 25as in the low basis weight portion 25aL is zero, so that in the low basis weight portion 25aL, the inner layer sheet 21, etc. and the non-skin side fibers 25bs of the non-skin side layer 25b of the sheet portion 25 can be melt-bonded without the skin side fibers 25as in between. This further reduces the risk of a decrease in bond strength at the side bond region SS.

[0102] Furthermore, as shown in Figure 6, when the side joints SS of a pair of waistband portions of the diaper 1 have multiple joints 70 intermittently arranged in the vertical direction, 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 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 and adverse effects on the wearer caused by moisture continuing to come into contact with the skin, while making it easier to provide a wider overlapping area between the joint 70 and the low-basis weight portion 25aL when viewed in the thickness direction of the diaper 1 than when the distance L70 between the centers 70c of the joints 70 in the vertical direction is shorter than the distance L3 between the centers P of the low-basis weight portions 25aL, thereby reducing the risk of a decrease in the bonding strength of the side joints SS (joints 70) on both left and right sides of the pair of waistband portions 20, 30.

[0103] Furthermore, when the side seams SS of a pair of waistbands of the diaper 1 have a plurality of seams 70 spaced apart in the up-down direction, it is preferable that the area of ​​a region Z defined by lines (imaginary lines in FIG. 6 ) connecting the centers P of four adjacent low-basis weight sections 25aL in the up-down direction (vertical direction) and left-right direction (horizontal direction) be larger than the minimum area of ​​the seams 70. This makes it easier to widen the overlapping region between the low-basis weight sections 25aL and the seams 70 in the thickness direction than when the area of ​​region Z is larger than the minimum area of ​​the seams 70. This reduces the risk that the overlapping region becomes too wide, resulting in an excessively strong bond at the side seams SS (seams 70), which could make it difficult to separate the ventral waistband section 20 and the back waistband section 30 after use of the diaper 1.

[0104] On the other hand, when the side seams SS of a pair of waistbands of the diaper 1 have a plurality of seams 70 spaced apart in the up-down direction, the area of ​​a region Z defined by lines (imaginary lines in FIG. 6 ) connecting the centers P of four adjacent low-basis weight regions 25aL in the up-down (vertical) and left-right (horizontal) directions may be smaller than the maximum area of ​​the seams 70. This makes it easier to provide a wider region where the low-basis weight regions 25aL and the seams 70 overlap when viewed in the thickness direction of the diaper 1 than when the area of ​​region Z is larger than the maximum area of ​​the seams 70, and thus makes it easier to increase the bond strength at the side seams SS (seams 70).

[0105] 7 to 10 show modified examples of the arrangement of the sheet member of the present invention. In each of the modified examples, the sheet member 25 is a sheet member having the above-mentioned characteristics.

[0106] 7A and 7B are diagrams illustrating a first modification of the arrangement of the sheet portion 25 of the present invention. In the first modification, no separate sheet member is 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) serves 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 will become 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. Furthermore, by having a joint portion (not shown) where the sheet portion 25 (35), which is 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 side in the thickness direction are joined by welding or adhesive, and a non-joined portion (not shown) where the sheet portion 25 (35) and the inner layer sheet 21 (adjacent sheet member) are not joined by welding or adhesive, it is possible to obtain the same effect as in the present embodiment described above. The folded-back portion 22 (32r) of the sheet portion 25 (35) in this modification is a tightly constricting portion of the ventral waistband 20 (dorsal waistband 30). The presence of the skin-side layer 25a on the skin-contacting surface of this portion allows the wearer to feel the softness of the skin-side fibers 25as, such as cotton fibers, more effectively. Furthermore, the non-bonded portion allows the sheet portion 25 (35) to more easily follow the movement of the waistband, thereby reducing friction with the skin and suppressing pilling of the skin-side fibers 25as, such as cotton fibers. While the first modification employs the folded-back portion 22r (32r) instead of the sheet portion 25 (35), this is not a limitation. The sheet portion 25 (35) may be positioned as shown in FIG. 7 regardless of whether the diaper 1 has the folded-back portion 22r (32r).

[0107] (Variation 2) Fig. 8 is a diagram illustrating Variation 2 of the arrangement of the sheet portion 25 of the present invention. In Variation 2 shown in Fig. 8, the sheet portion 25 (35) is not provided to both ends in the left-right direction of the ventral waistline portion 20 (dorsal waistline portion 30), but is provided in the left-right central portion of the ventral waistline portion 20 (dorsal waistline portion 30) and so as to straddle in the vertical direction the upper end 10e of the absorbent main body 10. Since the upper end 10e of the absorbent main body 10 is a portion where the unevenness is relatively large, by arranging the sheet portion 25 (35) so as to completely cover at least the upper end 10e, it is possible to suppress friction on the skin when worn and reduce irritation to the skin.

[0108] (Variation 3) Fig. 9 is a diagram illustrating Variation 3 of the arrangement of the sheet portion 25 of the present invention. In Variation 3 shown in Fig. 9, a sheet member that becomes the sheet portion 25 (35) is provided between the inner layer sheet 21 of the absorbent main body 10. The sheet member that becomes the sheet portion 25 is provided in the ventral waistline portion 20, between one end and the other end of the pair of side joints SS in the left-right direction, and in a region from the upper end to the lower end of the pair of side joints SS in the up-down direction. In the back waistline portion 30, the sheet member that becomes the sheet portion 35 is provided in the region from one end to the other end of the pair of side joints SS in the left-right direction, and in a region from the upper end to the vicinity of the lower end of the pair of side joints SS in the up-down direction. With this configuration, the skin-side layer 25a is present in most of the skin-contacting surface of the ventral waistline portion 20 (back waistline portion 30) in a region other than the region where the absorbent main body 10 is disposed, thereby improving the feel against the skin. Furthermore, since the sheet portion 25 (35) and the inner layer sheet 21 have a non-joined portion that is not joined by welding or adhesive, the sheet portion 25 (35) can easily follow the movement of the wearer's waist and reduce friction with the skin, thereby suppressing pilling of the skin-side fibers 25as, such as cotton fibers, even if the proportion of the skin-side layer 25a that comes into contact with the skin increases. Note that in the waistband portions 20 (30), the sheet portion 25 (35) may be arranged as the sheet located closest to the skin of the waistband portions 20 (30) instead of the inner layer sheets 21 (31).

[0109] Furthermore, when the non-skin-side fibers 25bs are thermoplastic fibers, the diaper 1 may have an adjacent member disposed at a position overlapping the sheet portion 25 in the thickness direction, the diaper 1 may have a welded joint where the sheet portion 25 and the adjacent member are welded in the thickness direction, and at least a portion of the welded joint overlaps the portion where the low basis weight portion 25aL and the non-skin-side layer 25b overlap in the thickness direction of the diaper 1. For example, in Modifications 1 to 3 shown in Figures 7 to 9, when the inner layer sheet 21 (or the ventral-side outer layer sheet 22) is positioned at a position overlapping the sheet portion 25 of the ventral waistband portion 20 in the thickness direction, the sheet portion 25 and the inner layer sheet 21 (or the ventral-side outer layer sheet 22) may have a welded joint (not shown) where the sheet portion 25 is welded in the thickness direction. In such a case, it is preferable that, when viewed in the thickness direction, at least a portion of the welded joint overlaps the portion where the low basis weight portion 25aL of the sheet portion 25 and the non-skin side layer 25b overlap, thereby reducing the risk of a decrease in the bonding strength of the welded joint that welds the sheet portion 25 and the inner layer sheet 21 (or the outer layer sheet 22).

[0110] In the above-described embodiment and Modifications 1 to 3, the sheet portion 25 is provided in the ventral waist portion 20 and the sheet portion 35 is provided in the back waist portion 30, but this is not limiting. Each diaper 1 may be configured such that the sheet portion 25 is provided only in the ventral waist portion 20 and the sheet portion 35 is not provided in the back waist portion 30, or such that the sheet portion 35 is provided only in the back waist portion 30 and the sheet portion 25 is not provided in the ventral waist portion 20.

[0111] (Variation 4) Figure 10 is a diagram illustrating Variation 4 of the arrangement of the sheet portion 25 of the present invention. In Variation 4 shown in Figure 10, the sheet portion 25 is provided as the top sheet 12 of the absorbent main body 10. The top sheet 12 is the member of the absorbent main body 10 that contacts the wearer's skin, and therefore, by providing the sheet portion 25 as the top sheet 12, it is possible to improve the feel against the skin by the skin-side fibers 25as of the skin-side layer 25a, while reducing discomfort to the wearer's skin and adverse effects on the wearer's skin.

[0112] The diaper 1 of the modified example shown in FIG. 10 may have a compressing member having a portion (not shown) compressed in the thickness direction. Examples of the compressing member include the absorbent core 11 and other components. The diaper 1 may have a sheet portion 25 (top sheet 12) disposed closer to the skin than the compressing member (absorbent core 11), and the portion where the low basis weight portion 25aL and the non-skin-side layer 25b overlap with the compressed portion of the compressing member (absorbent core 11) in the thickness direction. Generally, compressed portions have a high fiber density and are therefore more likely to absorb moisture due to capillary action. Therefore, if the compressing member (absorbent core 11) has a portion with a high density due to compression, moisture can be more easily transferred from the sheet portion 25 (top sheet 12) to the compressing member located closer to the skin than the sheet portion 25.

[0113] <Other Aspects of the Absorbent Article 1> In addition to the above-described aspects, the absorbent article 1 can have the following aspects.

[0114] (Other aspect 1) The absorbent article 1 may have a vertical direction and a thickness direction that intersect with each other, and include an absorbent main body 10, a ventral waistline portion 20 located on the ventral side of a wearer, and a back-side waistline portion 30 located on the back side of the wearer, wherein a sheet portion 25 (35) is provided on the side closest to the skin of at least one of the ventral waistline portion 20 and the back-side waistline portion 30, the sheet portion 25 (35) including a cotton layer (skin-side layer) 25 a based on cotton fibers (skin-side fibers) 25 as, and at least a portion of the sheet portion 25 (35) is located above the absorbent main body 10 in the vertical direction, and when a region of the sheet portion 25 (35) that is located above the absorbent main body 10 in the vertical direction is defined as an upper arrangement region, the absorbent article 1 may have a joint portion where the upper arrangement region and an adjacent sheet member adjacent to the upper arrangement region from the non-skin-side side in the thickness direction are joined by welding or adhesive, and a non-join portion where the upper arrangement region and the adjacent sheet member are not joined by welding or adhesive. According to this embodiment, the non-jointed portions of the sheet portion that come into contact with the skin are easily deformed, and when movement occurs in the waistband portion, the non-jointed portions follow such movement, reducing friction with the skin and thereby suppressing pilling of the cotton fibers 25as. At the same time, the presence of the joined portions also prevents the cotton fibers 25as from falling off. Furthermore, by continuously contacting the skin with the cotton layer 25a while reducing friction with the skin, the user can experience the softness of the cotton while suppressing irritation to the skin.

[0115] (Other Aspect 2) In the unfolded state and the stretched state, the total area of ​​the non-joined portions when the upper arrangement region is viewed in plan may be larger than the total area of ​​the joined portions of the absorbent article 1. According to this aspect, the larger total area of ​​the non-joined portions increases the number of portions that can follow movement when movement occurs around the waist, thereby reducing friction with the skin and suppressing pilling of the cotton layer 25a.

[0116] (Other Aspect 3) The absorbent article 1 may have a structure in which the total length of the joined portions in the vertical direction is longer than the total length of the non-jointed portions. According to this aspect, providing a large number of non-jointed portions can suppress pilling of the cotton layer 25a, but on the other hand, there is a risk that the joint between the sheet portion 25 (35) and the adjacent sheet member may peel off. By making the total length of the joined portions in the vertical direction longer than the total length of the non-jointed portions, it is possible to make the joint less likely to peel off.

[0117] (Other Aspect 4) The sheet portion may have a non-skin-side layer 25b located on the non-skin-side side of the cotton layer 25a in the thickness direction, and the absorbent article 1 may have non-skin-side fibers 25bs, which are base fibers of the non-skin-side layer 25b, having a longer average fiber length than the average fiber length of the cotton fibers 25as. According to this aspect, the cotton fibers 25as are bonded to fibers with a longer average fiber length, thereby improving the durability of the cotton layer 25a and making the cotton fibers 25as less likely to fall off. Furthermore, when the sheet portion 25 (35) is bonded to an adjacent sheet member, the longer average fiber length of the non-skin-side fibers 25bs located on the non-skin-side side of the sheet portion 25 (35) makes the bond less likely to come off, improving conformity to the adjacent sheet member.

[0118] (Other Aspect 5) The sheet portion 25 (35) may have a non-skin-side layer 25b located on the non-skin-side side of the cotton layer 25a in the thickness direction, and the absorbent article 1 may have cotton fibers 25as with a lower thermal conductivity than non-skin-side fibers 25bs, which are the base fibers of the non-skin-side layer 25b. According to this aspect, the cotton fibers 25as that contact the wearer's skin have a low thermal conductivity, so even if the cotton layer 25a becomes wet with sweat or the like while being worn, the cotton layer 25a is unlikely to immediately cool down. Furthermore, because 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, heat transferred to the non-skin-side layer 25b is released further away from the non-skin-side layer 25b, making it less likely for heat to build up 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 that are the base fibers of the cotton layer 25a is higher than the hydrophilicity of the non-skin-side fibers 25bs that are the base fibers of the non-skin-side layer 25b. According to this aspect, the cotton layer 25a, which has highly hydrophilic cotton fibers 25as as its base fibers, is disposed on the surface that contacts the wearer's skin, thereby improving water absorption, and the non-skin-side fibers 25bs that are the base fibers of the non-skin-side layer 25b have a lower hydrophilicity than the cotton fibers 25as, so that when moisture such as sweat absorbed by the cotton fibers 25as moves to the non-skin side, the non-skin-side layer 25b does not excessively retain moisture and promotes evaporation, thereby preventing stuffiness.

[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, the inclusion of cotton fibers 25as allows the user to feel a pleasant texture against the skin, and at the same time, the low mass proportion of cotton fibers 25as suppresses pilling of the cotton layer 25a.

[0121] (Other Aspect 8) The cotton layer 25a may be an absorbent article 1 having a predetermined basis weight portion 25aP including cotton fibers 25as of a predetermined basis weight and a low basis weight portion 25aL including cotton fibers 25as with a lower basis weight than the predetermined basis weight portion 25aP. According to this aspect, the low basis weight portion 25aL having a low basis weight can prevent the cotton fibers 25as, which have a short average fiber length, from falling out. Therefore, it is possible to achieve both a comfortable feel due to the cotton fibers 25as included in the predetermined basis weight portion 25aP and prevention of the cotton fibers 25as from falling out.

[0122] (Other Aspect 9) An absorbent article 1 may have a left-right direction perpendicular to the up-down direction and the thickness direction, and at least one of the ventral waistline portion 20 and the back-side waistline portion 30 has an inner layer sheet 21, an outer layer sheet 22, 32 arranged closer to the skin than the inner layer sheet 21, and a plurality of left-right stretchable waistline elastic members 23, 33 arranged at intervals in the up-down direction between the inner layer sheet 21 and the outer layer sheet 22, 32, and the cotton layer 25a has a plurality of low basis weight portions 25aL arranged at intervals in the up-down direction, and the minimum value of the distance between the centers P of adjacent low basis weight portions 25aL in the up-down direction is smaller than the minimum value of the distance between the centers P of adjacent waistline elastic members 23, 33 in the up-down direction. According to this aspect, by providing a plurality of low basis weight portions 25aL with small intervals in the up-down direction, it is possible to further suppress shedding of cotton fibers 25as, which have a short average fiber length, and to further suppress irritation to the skin due to shedding of fibers.

[0123] (Other Aspect 10) The sheet portion 25 (35) may be an absorbent article 1 that is a sheet member that is arranged closer to the skin than the inner layer sheet 21. According to this aspect, the waist elastic members 23, 33 are arranged between the inner layer sheet 21 and the outer layer sheets 22, 32, and therefore there is an area of ​​interference between the waist elastic members 23, 33 and the sheet portion (sheet member) that includes the cotton layer 25a. This prevents the cotton layer 25a on the skin side from stretching excessively, reducing friction between the cotton layer 25a and the skin and suppressing shedding and fluffing of the cotton fibers 25as.

[0124] (Other aspect 11) The sheet portion 25 (35) is arranged below and spaced from the upper end of at least one of the ventral waistline portion 20 and the back waistline portion 30 in the vertical direction, and when the region in the vertical direction from the upper end of the ventral waistline portion 20 or the back waistline portion 30 where the sheet portion 25 is provided to the upper end of the sheet portion 25 is defined as a non-arrangement region, and the region in the vertical direction from the upper end to the lower end of the sheet portion 25 of the ventral waistline portion 20 or the back waistline portion 30 where the sheet portion is provided is defined as a arrangement region, the portion of the non-arrangement region closest to the skin contains hydrophobic fibers, and the magnitude of the force required to stretch the non-arrangement region of a unit width in the vertical direction by a unit length in the horizontal direction may be greater than the magnitude of the force required to stretch the arrangement region of a unit width in the vertical direction by a unit length in the horizontal direction. According to this embodiment, the skin-facing side of the non-placement area, which has a strong grip, contains hydrophobic fibers, thereby suppressing stickiness and reducing discomfort to the wearer's body, and the placement area of ​​the sheet portion, which is prone to pilling when the grip is strong, has a weaker gripping force, thereby reducing friction with the skin and suppressing pilling of the cotton fibers.

[0125] (Other Aspect 12) The absorbent article 1 may have a length in the up-down direction of the sheet portion 25 (35) that is equal to or less than half the length of the ventral waistline portion 20 or the dorsal waistline portion 30. According to this aspect, the cotton layer 25a of the sheet portion 25 reduces friction on the skin, while reducing the length of the cotton layer 25a suppresses pilling. Therefore, the cotton layer 25a provides a pleasant feel to the skin, reduces irritation to the skin, and prevents pilling.

[0126] (Other Aspect 13) At least one of the ventral waistline portion 20 and the dorsal waistline portion 30 may have an inner layer sheet 21, an outer layer sheet 22 (32) disposed closer to the skin than the inner layer sheet 21, and a folded-back portion 22r (32r) formed by folding back the upper end of the outer layer sheet 22 in the vertical direction toward the skin, and the absorbent article 1 may have a length of the sheet portion 25 longer in the vertical direction than the length of the folded-back portion 22r. According to this aspect, by providing the sheet portion longer than the vertical length of the folded-back portion 22r, it becomes easier to feel the pleasant feel of the cotton layer 25a against the skin.

[0127] (Other Aspect 14) At least one of the ventral waistline portion 20 and the dorsal waistline portion 30 may have an inner layer sheet 21, an outer layer sheet 22 (32) disposed closer to the skin than the inner layer sheet 21, and a folded-back portion 22r (32r) formed by folding back the upper end of the outer layer sheet 22 in the vertical direction toward the skin, and the length of the sheet portion 25 in the vertical direction may be shorter than the length of the folded-back portion 22r. According to this aspect, by not disposing the sheet portion 25 to be excessively long in the vertical direction, the possibility of pilling of the cotton layer 25a is further reduced.

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

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

[0130] (Other aspect 17) The absorbent article 1 may be an absorbent article 1 having an absorbent main body 10, a ventral waistline portion 20 located on the ventral side of a wearer, and a dorsal waistline portion 30 located on the dorsal side of the wearer, wherein the absorbent article 1 has a sheet portion 25 (35) located closest to the skin of at least one of the ventral waistline portion 20 and the dorsal waistline portion 30, the sheet portion 25 (35) and an adjacent sheet member adjacent to the sheet portion 25 (35) from the non-skin-facing side are joined by adhesion or welding, the sheet portion 25 (35) has a skin-side layer 25 a that abuts the wearer's skin, and a non-skin-side layer 25 b that is located on the non-skin-facing side of the skin-side layer, and the hydrophilicity of the skin-side fiber 25 as that is the base fiber of the skin-side layer 25 a is higher than the hydrophilicity of the non-skin-side fiber 25 bs that is the base fiber of the non-skin-side layer 25 b. According to this embodiment, the skin-side layer 25a easily absorbs sweat and excrement because the skin-side fibers 25as have high hydrophilicity. On the other hand, the non-skin-side layer 25b, which is the base fiber of the non-skin-side fibers 25bs, has lower hydrophilicity than the skin-side fibers 25as. This allows the sheet portion 25 to maintain its adhesive strength with the adjacent sheet member even when it gets wet, preventing it from peeling off. This allows the sheet portion 25 to perform its intended function and prevents the sheet portion 25 from peeling off, which could impair the comfort of wearing the garment.

[0131] (Other Aspect 18) The absorbent article 1 may be characterized in that the content of the skin side fibers 25as in the sheet portion 25 is 50 mass % or less. According to this aspect, if the mass proportion of the highly hydrophilic skin side fibers 25as in the entire sheet portion 25 becomes too high, there is a risk that the adhesive strength between the sheet portion 25 and adjacent sheet members may be weakened when the sheet portion 25 becomes wet. However, this can be avoided by reducing the mass proportion of the skin side fibers 25as in the entire sheet portion 25.

[0132] (Other Aspect 19) The absorbent article 1 may be characterized in that at least a portion of the skin-side fibers 25as in the skin-side layer 25a are flush with the non-skin-side surface of the non-skin-side layer 25b. According to this aspect, moisture absorbed by the skin-side layer 25a can be rapidly transferred to the non-skin-side layer 25b along the extending skin-side fibers 25as. This allows excess moisture in the skin-side layer 25a to 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 retain too much of the transferred moisture and can maintain its adhesive strength with the adjacent sheet member. This prevents the sheet portion 25 from peeling off unexpectedly, thereby preventing a loss of comfort when worn.

[0133] (Other Aspect 20) The absorbent article 1 may be characterized in that, when the welded portions are defined as portions where fibers are welded to each other in the skin side layer 25a and the non-skin side layer 25b, the total volume of the welded portions per unit volume of the non-skin side layer 25b is larger than the total volume of the welded portions 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 contained in the skin side layer 25a and the non-skin side layer 25b. For example, if the skin-side layer 25a contains thermoplastic fibers other than cotton fibers (skin-side fibers) 25as, the welded portions in the skin-side layer 25a may be portions where the thermoplastic fibers in the skin-side layer 25a are welded to the non-skin-side fibers 25bs, which are thermoplastic fibers in the non-skin-side layer 25b. If the skin-side layer 25a is formed solely of cotton fibers (skin-side fibers) 25as, no welded portions exist. According to this embodiment, the skin-side layer 25a has few (or no) welded portions, allowing moisture to easily penetrate between the fibers and absorb moisture from the wearer's skin. Meanwhile, the non-skin-side layer 25b has welded portions, ensuring a smooth surface and making it easier to maintain adhesive strength even when the sheet portion becomes wet. Furthermore, the presence of welded portions in the non-skin-side layer 25b improves the overall strength of the sheet portion 25, thereby making it less likely to separate from adjacent sheet members.

[0134] (Other Aspect 21) The absorbent article 1 may be characterized in that the ratio of the total volume of the welded portions to the entire volume of the non-skin side layer 25b is 5% or more and 25% or less. According to this aspect, the presence of the welded portions at such a ratio ensures the smoothness of the surface of the non-skin side layer 25b, makes it easier for the sheet portion 25 to maintain its adhesive strength even when it gets wet, and improves the strength of the sheet portion 25 as a whole. This makes it less likely for the sheet portion 25 to peel from the adjacent sheet member.

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

[0136] (Other Aspect 23) The non-skin side layer 25b may have a non-skin side portion of the non-skin side located on the skin side in the thickness direction of the non-skin side layer 25b and a non-skin side portion of the non-skin side located on the non-skin side, and the fiber density of the non-skin side fibers 25bs in the non-skin side portion of the non-skin side layer may be higher than the fiber density of the non-skin side fibers 25bs in the non-skin side portion of the non-skin side layer. According to this aspect, a higher fiber density makes it easier to absorb liquid, and when the fiber density of the non-skin side portion of the non-skin side layer is high, the high fiber density portion of the non-skin side fibers 25bs is located adjacent to the highly hydrophilic skin side layer 25a, so that moisture absorbed by the skin side fibers 25as is absorbed into the skin side portion of the non-skin side layer, reducing the moisture in the skin side layer 25a and suppressing stickiness, etc., of the portion in contact with the skin.

[0137] (Other Aspect 24) The absorbent article 1 may be characterized in that the non-skin side layer 25b has a non-skin side portion of the non-skin side located on the skin side in the thickness direction of the non-skin side layer 25b and a non-skin side portion of the non-skin side of the non-skin side layer, and the hydrophilicity of the non-skin side fibers 25bs in the non-skin side portion of the non-skin side layer is higher than the hydrophilicity of the non-skin side fibers 25bs in the non-skin side portion of the non-skin side layer. According to this aspect, the non-skin side portion of the non-skin side layer is a portion that abuts the skin side fibers 25as of the skin side layer 25a, and increasing the hydrophilicity of the non-skin side fibers 25bs in the non-skin side portion of the non-skin side layer facilitates the transfer of moisture 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 portion of the non-skin side layer, which has low hydrophilicity, and evaporation is more easily promoted. Since moisture is less likely to accumulate in the non-skin side portion of the non-skin side layer, adhesion between the non-skin side layer 25b and the adjacent sheet member can be more easily maintained.

[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 of at least one of polypropylene, polyethylene, and polyurethane that have been hydrophilized. According to this aspect, the skin-side layer 25a contains cotton fibers, which facilitates moisture absorption from the skin. The non-skin-side layer 25b contains the hydrophobic fibers (or hydrophilized fibers), which allow excess moisture from the skin-side layer 25a to be removed without retaining moisture after transferring to the non-skin-side layer 25b, thereby maintaining adhesive strength with the adjacent sheet member. This prevents unintended peeling of the sheet portion 25, which would impair comfort.

[0139] (Other Aspect 26) The absorbent article 1 may be characterized in that the non-skin side layer 25b has a predetermined basis weight portion including non-skin side fibers 25bs of a predetermined basis weight and a low basis weight portion having non-skin side fibers 25bs with a lower basis weight than the predetermined basis weight portion 25b, and 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, the overlapping portion promotes the drawing of 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. This allows moisture to be removed more quickly from the sheet portion 25, thereby maintaining adhesive strength and preventing peeling of the sheet portion 25.

[0140] ===Other=== The above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0141] DESCRIPTION OF SYMBOLS 1 Diaper (pants-type disposable diaper, absorbent article) 10 Absorbent body 10e Upper end 11 Absorbent core (absorbent body) 12 Top sheet 13 Back sheet 14 Outer sheet 15 Leg-hole elastic member 18 Outer body 20 Abdominal waist portion 20e Upper end 21 Inner layer sheet 22 Abdominal outer layer sheet 22r Folded-back portion 23 Waist elastic member 25 Sheet portion 25a Skin-side layer (cotton layer) 25aL Low basis weight portion 25aP Predetermined basis weight portion 25as Skin-side fiber (cotton fiber) 25b Non-skin-side layer 25bs Non-skin-side fiber 30 Back waist portion 32 Back outer layer sheet 32r Folded-back portion 33 Waist elastic member 34 Rear leg-hole elastic member 35 Sheet portion 40 Crotch SS Side joint (joint)

Claims

1. A sheet member for absorbent articles 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 fiber which is the base fiber of the skin side layer is higher than the hydrophilicity of the non-skin side fiber which is the base fiber of the non-skin side layer, the skin side layer has a predetermined basis weight section comprising the skin side fiber of a predetermined basis weight, and a low basis weight section in which the basis weight of the skin side fiber is lower than that of the predetermined basis weight section, and the sheet member has, when viewed in the thickness direction, a portion where the predetermined basis weight section and the non-skin side layer overlap, and a portion where the low basis weight section and the non-skin side layer overlap.

2. A sheet member according to claim 1, characterized in that the skin side fibers and the non-skin side fibers have a portion where they are entangled.

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

4. A sheet member as described in claim 1 or 2, characterized in that the sheet member has a vertical direction and a horizontal direction perpendicular to the thickness direction, the specified basis weight sections and the low basis weight sections are arranged alternately in the vertical direction, and the specified basis weight sections and the low basis weight sections are arranged alternately in the horizontal direction.

5. A 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 specified basis weight portion.

6. A sheet member according to claim 1 or 2, characterized in that at least a portion of the non-skin side fibers are present on the skin side of the skin side layer.

7. A sheet member according to claim 1 or 2, characterized in that no adhesive is provided on the sheet member.

8. A sheet member according to claim 1 or 2, characterized in that the sheet member does not have a portion where the sheet member is compressed in the thickness direction.

9. A sheet member according to claim 1 or 2, characterized in that the sheet member has a sheet compression portion in which the skin side layer and a part of the skin side layer are compressed in the thickness direction.

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

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

12. A sheet member as described in claim 1 or 2, wherein the absorbent article has a stretchable member, and the sheet member is used in a position overlapping at least a portion of the stretchable member when viewed in the thickness direction in the absorbent article in an unfolded and stretched state.

13. A sheet member as described in claim 1 or 2, wherein the absorbent article has a compressing member having a portion compressed in the thickness direction, and in the absorbent article, the sheet member is provided on the skin side of the compressing member, and when viewed in the thickness direction, a portion where the low basis weight portion and the non-skin side layer overlap has a portion that overlaps with the compressed portion of the compressing member.

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

15. A sheet member as described in claim 1 or 2, wherein the non-skin side fibers are thermoplastic fibers, the absorbent article has an adjacent member arranged at a position overlapping the sheet member when viewed in the thickness direction, the absorbent article has a welded joint where the sheet member and the adjacent member are welded and joined in the thickness direction, and the sheet member is characterized in that when the absorbent article is viewed in the thickness direction, the portion where the low basis weight portion and the non-skin side layer overlap overlaps at least a portion of the welded joint.

16. A sheet member as described in claim 1 or 2, wherein the non-skin side fibers are thermoplastic fibers, the absorbent article has a joint where both left and right side portions of a pair of waistband portions are welded together, the sheet member is used in a position overlapping at least a portion of the joint when viewed in the thickness direction, and the joint overlaps at least a portion of the portion where the low basis weight portion and the non-skin side layer overlap.

17. A sheet member as described in claim 16, wherein the pair of waistband portions have a plurality of intermittent joints in the vertical direction, and the distance between the centers of adjacent joints in the vertical direction is longer than the distance between the centers of the low basis weight portions.

18. A sheet member as described in claim 16, wherein the joints are provided intermittently in the vertical direction, the sheet member has a vertical direction and a horizontal direction perpendicular to the thickness direction, and the area of ​​a region bounded by straight lines connecting the centers of four low basis weight sections adjacent to each other in the vertical direction and the horizontal direction is smaller than the maximum area of ​​the joints.

19. A sheet member as described in claim 16, wherein the joints are provided intermittently in the up-down direction, the sheet member has a vertical direction and a horizontal direction perpendicular to the thickness direction, and the area of ​​a region bounded by straight lines connecting the centers of four low basis weight sections adjacent to each other in the vertical direction and the horizontal direction is larger than the minimum area of ​​the joints.

20. An absorbent article comprising: an absorbent body; and a sheet member provided on the skin side of the absorbent body, 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, wherein the hydrophilicity of the skin side fiber which is the base fiber of the skin side layer is higher than the hydrophilicity of the non-skin side fiber which is the base fiber of the non-skin side layer, wherein the skin side layer has a predetermined basis weight section comprising the skin side fiber of a predetermined basis weight, and a low basis weight section in which the basis weight of the skin side fiber is lower than that of the predetermined basis weight section, and wherein, when viewed in the thickness direction, the absorbent article has a portion where the predetermined basis weight section and the non-skin side layer overlap, and a portion where the low basis weight section and the non-skin side layer overlap.

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