Nonwoven fabrics for absorbent articles and top sheets

Abstract

To provide an absorbent article that enhances both liquid drainage at the top sheet and absorption performance. [Solution] The absorbent article 1 has a longitudinal direction, a width direction, and a thickness direction, and comprises a top sheet 7 and an absorbent body 8 located on the non-skin side of the top sheet 7. The top sheet 7 includes a flat portion 51 that is in contact with the skin, and a plurality of recesses 52 that are recessed from the skin-side surface of the flat portion 51 toward the absorbent body 8. Each of the plurality of recesses 52 includes a bottom portion BS that is in contact with the absorbent body 8, and a peripheral wall portion SW that extends from the periphery of the bottom portion BS toward the flat portion 51. The thickness of the flat portion 51 and the thickness of the bottom portion BS are 0.7 to 1.3 times that of the other.

Description

TECHNICAL FIELD

[0001] The present invention relates to an absorbent article and a nonwoven fabric for a topsheet.

BACKGROUND ART

[0002] Absorbent articles including a topsheet having recesses and / or protrusions on the surface are known. For example, Patent Document 1 discloses a topsheet for an absorbent article in which a nonwoven fabric is formed with a surface portion whose surface side comes into contact with the skin, and a large number of liquid-guiding recesses whose surface side is concave and whose back surface side protrudes toward the absorbent body. In this topsheet for an absorbent article, the liquid-guiding recess has a peripheral wall portion and a bottom surface portion, the bottom surface portion is located closer to the absorbent body than the back surface of the surface portion, and the thickness of the portion of the peripheral wall portion adjacent to the bottom surface portion is smaller than the thickness of the surface portion.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0003]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0004] In Patent Document 1, in the topsheet, by increasing the fiber density near the bottom surface of the recess (liquid-guiding recess), a capillary phenomenon is induced, so that body fluid is efficiently and quickly transferred to the absorbent body through the recess, thereby attempting to improve the absorption performance.

[0005] However, when there is a large amount of bodily fluid, capillary action in the recesses alone is insufficient to quickly transfer the fluid to the absorbent material. Furthermore, the thickness of the part that comes into contact with the skin (the surface) is greater than the thickness of the part adjacent to the bottom surface of the peripheral wall, and is therefore too thick, making it easier for the part in contact with the skin to retain bodily fluid. Consequently, bodily fluid is more likely to be temporarily retained in the part in contact with the skin before it can transfer from the part in contact with the skin to the bottom surface. In other words, the liquid drainage performance of the top sheet decreases. As a result, the top sheet is more likely to become wet during use, which may cause discomfort to the user.

[0006] Therefore, the object of the present invention is to provide an absorbent article and a nonwoven fabric for a top sheet that can improve absorption performance while enhancing liquid drainage at the top sheet. [Means for solving the problem]

[0007] The absorbent article in the present invention comprises a top sheet having a longitudinal direction, a width direction, and a thickness direction, and an absorbent body located on the non-skin side of the top sheet, wherein the top sheet includes a flat portion in contact with the skin and a plurality of recesses that are recessed from the skin-side surface of the flat portion toward the absorbent body, and each of the plurality of recesses includes a bottom portion in contact with the absorbent body and a peripheral wall portion extending from the periphery of the bottom portion toward the flat portion, and the thickness of the flat portion and the thickness of the bottom portion are 0.7 to 1.3 times that of the other, in the present invention.

[0008] The nonwoven fabric for top sheet in the present invention is a nonwoven fabric for top sheet of an absorbent article, wherein the nonwoven fabric includes a flat portion having a first surface and a plurality of recesses that are recessed from the first surface of the flat portion toward the absorbent, and each of the plurality of recesses includes a bottom surface and a peripheral wall portion that extends from the periphery of the bottom surface toward the flat portion, and the thickness of the flat portion and the thickness of the bottom surface are 0.7 to 1.3 times that of the other. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an absorbent article and a nonwoven fabric for a top sheet that can improve absorption performance while enhancing liquid drainage at the top sheet. [Brief explanation of the drawing]

[0010] [Figure 1] This is a plan view showing an example of the structure of an absorbent article according to an embodiment, in an unfolded state. [Figure 2] This is a cross-sectional view along the longitudinal centerline CL in Figure 1. [Figure 3] This is a cross-sectional view along the widthwise centerline CW in Figure 1. [Figure 4] This is a schematic plan view showing an example of the configuration of a nonwoven fabric for a top sheet according to the embodiment. [Figure 5] This is a cross-sectional view along the Va-Va and Vb-Vb lines in Figure 4. [Figure 6] This is a schematic diagram illustrating an example of a method for manufacturing a nonwoven fabric for a top sheet according to an embodiment. [Modes for carrying out the invention]

[0011] This embodiment relates to the following aspects.

[0012] [Aspect 1] An absorbent article comprising a top sheet having a longitudinal direction, a width direction and a thickness direction, and an absorbent body located on the non-skin side of the top sheet, wherein the top sheet includes a flat portion in contact with the skin and a plurality of recesses that are recessed from the skin-side surface of the flat portion toward the absorbent body, and each of the plurality of recesses includes a bottom portion in contact with the absorbent body and a peripheral wall portion extending from the periphery of the bottom portion toward the flat portion, and the thickness of the flat portion and the thickness of the bottom portion are 0.7 to 1.3 times that of the other.

[0013] In this absorbent article, the bottom surface of each of the multiple recesses is in contact with the absorbent material. Therefore, bodily fluids can be quickly transferred from each of the multiple recesses to the absorbent material via the bottom surface. As a result, the absorbent material can quickly absorb bodily fluids. Furthermore, the thickness of the flat portion that comes into contact with the skin is approximately the same as (0.7 to 1.3 times) the thickness of the bottom portion that comes into contact with the absorbent material, and is not too thick. In this way, the thickness of the flat portion is not too thick, which reduces the amount of liquid that is temporarily held in the flat portion. In addition, the thickness of the flat portion is not too thick, which allows for a wider gap between the flat portion and the absorbent material, thereby allowing bodily fluids to be quickly transferred from the flat portion to that gap. As a result, the liquid drainage of the flat portion, and consequently the top sheet, is improved. Consequently, the top sheet is less likely to become wet during use, and the user is less likely to feel discomfort. Therefore, it is possible to provide an absorbent article that can improve both the liquid drainage of the top sheet and the absorption performance. Furthermore, because the recessed and flat areas are easily visible before and after use, users can easily perceive the instantaneous absorption of bodily fluids due to the indented shape of the recessed area, and the diffusion of bodily fluids in the longitudinal and widthwise directions due to the planar shape of the flat area, thus providing a sense of security.

[0014] [Aspect 2] The absorbent article according to embodiment 1, wherein the flat portion includes a plurality of longitudinal flat portions extending along the longitudinal direction and arranged at intervals in the width direction, and a plurality of width direction flat portions arranged between adjacent longitudinal flat portions among the plurality of longitudinal flat portions, extending along the width direction and arranged at intervals in the longitudinal direction.

[0015] In this absorbent article, the flat portion includes a plurality of longitudinal flat sections extending along the longitudinal direction, and a plurality of width-direction flat sections arranged between adjacent longitudinal flat sections and extending along the width direction. That is, the longitudinal flat sections form a continuous linear path in the longitudinal direction. On the other hand, the width-direction flat sections are interrupted by the longitudinal flat sections, forming discontinuous linear paths in the width direction, that is, zigzag paths. Therefore, body fluid tends to diffuse quickly in the longitudinal direction along the longitudinal flat sections. Accordingly, the body fluid can be quickly spread over a wide region in the longitudinal direction of the absorber and absorbed quickly. On the other hand, when body fluid diffuses along the width-direction flat sections, its progress tends to be slowed by the longitudinal flat sections, and it tends to be guided toward the longitudinal direction midway. Accordingly, while the absorber is used for absorbing body fluid over a wide region in the width direction, leakage of body fluid from the edge in the width direction (side leakage) can be suppressed. Therefore, side leakage can be suppressed while the absorber is used over a wide region, so that the absorption performance can be further improved.

[0016] [Aspect 3] The absorbent article according to Aspect 1 or 2, wherein the shortest distance between the recesses adjacent in the width direction in each of the plurality of recesses is larger than the shortest distance between the recesses adjacent in the longitudinal direction in each of the plurality of recesses.

[0017] In this absorbent article, the shortest distance between the recesses adjacent in the width direction is larger than the shortest distance between the recesses adjacent in the longitudinal direction. In other words, in the flat portion, the portion that exists between the recesses adjacent in the width direction and extends in the longitudinal direction (longitudinal flat section) is relatively thick, and the portion that exists between the recesses adjacent in the longitudinal direction and extends in the width direction (width-direction flat section) is relatively thin. Therefore, body fluid tends to diffuse quickly in the longitudinal direction along the relatively thick portion extending in the longitudinal direction in the flat portion. Accordingly, the body fluid can be quickly spread over a wide region in the longitudinal direction of the absorber and absorbed quickly. Thereby, the absorption performance can be further improved. Furthermore, the presence of flat portions on both longitudinal sides of the recess makes it easier for bodily fluids to diffuse to a certain extent in the width direction, compared to a case where the recesses are continuous in the longitudinal direction. Therefore, the absorber can be used to absorb bodily fluids over a wide region not only in its longitudinal direction but also in its width direction. As a result, the absorption performance can be further enhanced.

[0018] [Aspect 4] The absorbent article according to any one of Aspects 1 to 3, wherein each of the plurality of recesses has a longer length in the longitudinal direction than a length in the width direction in a plan view.

[0019] In the present absorbent article, each recess has a longer length in the longitudinal direction than the length in the width direction in a plan view. Thereby, the flat portions existing between the recesses adjacent in the width direction can be made to extend relatively long in the longitudinal direction. Therefore, bodily fluids can easily diffuse quickly in the longitudinal direction along the portions of the flat portions that extend relatively long in the longitudinal direction (longitudinal flat portions). Accordingly, bodily fluids can be quickly spread over a wide region in the longitudinal direction of the absorber and rapidly absorbed. As a result, the absorption performance can be further enhanced.

[0020] [Aspect 5] The absorbent article according to any one of Aspects 1 to 4, wherein the length in the width direction of each of the plurality of recesses is longer than the shortest distance between the recesses adjacent in the width direction among the plurality of recesses.

[0021] In the present absorbent article, the length in the width direction of each recess is longer than the shortest distance between adjacent recesses. Therefore, when bodily fluids excreted onto the top sheet diffuse in the width direction, they are easily captured by any of the recesses. Accordingly, the bodily fluids are drawn into one of the recesses without leaking out from the edge in the width direction (side leakage), and are reliably absorbed by the absorber. Thereby, bodily fluids can be reliably and quickly absorbed by the plurality of recesses, and the absorption performance can be further enhanced.

[0022] [Aspect 6] The absorbent article according to any one of embodiments 1 to 5, wherein the thickness of the peripheral wall portion gradually decreases from the flat portion side toward the bottom portion side.

[0023] In this absorbent article, the thickness of the peripheral wall gradually decreases from the flat side to the bottom side. As a result, the fiber density of the peripheral wall gradually increases from the flat side to the bottom side, which suppresses the flow of bodily fluids in the recesses towards the flat side. This makes it easier for bodily fluids stored in each of the multiple recesses to transfer to the absorbent material, thereby improving the absorption performance.

[0024] [Aspect 7] The absorbent article according to any one of embodiments 1 to 6, wherein the thickness of the portion of the peripheral wall adjacent to the flat portion is smaller than the thickness of the flat portion.

[0025] In this absorbent material, the thickness of the portion of the peripheral wall adjacent to the flat portion is smaller than the thickness of the flat portion itself. Therefore, bodily fluids from the flat portion easily migrate to the peripheral wall (which has a relatively high fiber density). Consequently, the flat portion is prevented from retaining bodily fluids. Furthermore, the bodily fluids stored in the flat portion are migrated to the space between the flat portion and the absorbent material, and also to the bottom surface via the peripheral wall of the recess, both of which can be easily migrated to the absorbent material. Thus, the absorption performance can be further enhanced.

[0026] [Aspect 8] The absorbent article according to any one of embodiments 1 to 7, wherein the area ratio of the plurality of recesses on the top sheet is greater than the area ratio of the flat portion on the top sheet.

[0027] In this absorbent material, the area ratio of the recesses in the top sheet is larger than the area ratio of the flat areas, resulting in a larger area of ​​the recesses (and their bottom surfaces) in contact with the absorbent material. This allows for rapid transfer of bodily fluids to the absorbent material via the recesses, even in large quantities, thus ensuring effective absorption. Furthermore, because the recessed area is easily visible before and after use, the user can more easily feel the instantaneous absorption of bodily fluids due to the indented shape of the recess, and thus feel more secure.

[0028] [Aspect 9] The absorbent article according to any one of embodiments 1 to 8, wherein the distance between the flat portion and the absorbent is longer than the distance between the bottom portion and the absorbent.

[0029] In this absorbent product, the distance between the flat section and the absorbent material is longer than the distance between the bottom section and the absorbent material. Therefore, because there is a larger space between the flat section and the absorbent material, bodily fluids can be transferred to that space more quickly through the flat section. This improves the liquid drainage of the flat section, and consequently the top sheet. Also, when excrement excreted on the top sheet is being absorbed into the absorbent material, the liquid drainage is higher in the flat section, making it more difficult to see the color of the excrement compared to the recessed area. As a result, the user is more likely to feel dry and more secure.

[0030] [Aspect 10] An absorbent article according to any one of embodiments 1 to 9, wherein the flat portion or the plurality of recesses have openings.

[0031] In this absorbent article, having openings in the flat portion or the multiple recesses allows for good absorption of bodily fluids with a certain degree of viscosity through these openings. This further enhances the absorbent performance of the absorbent article.

[0032] [Aspect 11] The absorbent article according to any one of embodiments 1 to 10, further comprising a material adjacent to the non-skin side of the top sheet, wherein the color of the top sheet is different from the color of the material.

[0033] In this absorbent product, the color of the top sheet differs from the color of the material adjacent to the non-skin side of the top sheet. In this case, the color of the adjacent material viewed through the flat part of the top sheet and the color of the adjacent material viewed through the recessed part appear to be different. Therefore, the flat part and the recessed part can be easily seen. As a result, the user can more easily perceive the instantaneous absorption of bodily fluids due to the indented shape of the recessed part and the rapid diffusion of bodily fluids in the longitudinal / width directions due to the planar shape of the flat part, and thus feel more secure.

[0034] [Aspect 12] The absorbent article according to any one of embodiments 1 to 11, further comprising a material disposed on the non-skin side of the absorbent body and a packaging bag for enclosing the absorbent article, wherein at least one of the non-skin surface of the material and the outer surface of the packaging bag has a pattern design that includes the flat portion and the plurality of recesses of the top sheet.

[0035] In this absorbent product, the non-skin-facing material of the absorbent core and at least one of the packaging bag for the absorbent product are printed with a pattern design that includes flat and recessed areas of the top sheet. This allows the user to recognize the pattern including the flat and recessed areas of the top sheet through the appearance of the packaging bag, the absorbent product, and the surface of the top sheet during a series of actions such as purchasing, using, and disposing of the product. As a result, the instantaneous absorption of bodily fluids due to the indented shape and the rapid diffusion of bodily fluids in the longitudinal and widthwise directions due to the planar shape of the flat areas can be recognized even before using the absorbent product, making it easier for the user to feel and feel more secure.

[0036] [Aspect 13] A nonwoven fabric for a top sheet of an absorbent article, wherein the nonwoven fabric includes a flat portion having a first surface and a second surface which is the back surface of the first surface, and a plurality of recesses that are recessed from the first surface toward the second surface of the flat portion, each of the plurality of recesses including a bottom surface and a peripheral wall portion extending from the periphery of the bottom surface toward the flat portion, and the thickness of the flat portion and the thickness of the bottom surface are 0.7 to 1.3 times that of the other.

[0037] When this nonwoven fabric for top sheets is used as a top sheet for absorbent articles, the bottom surface of each of the multiple recesses is positioned in contact with the absorbent material. In this case, bodily fluids can be quickly transferred from each of the multiple recesses to the absorbent material via the bottom surface. This allows the absorbent material to quickly absorb bodily fluids. Furthermore, the thickness of the flat portion that comes into contact with the skin is approximately the same as (0.7 to 1.3 times) the thickness of the bottom portion that comes into contact with the absorbent material, and is not too thick. By keeping the thickness of the flat portion not too thick, the amount of liquid temporarily held in the flat portion can be reduced. In addition, keeping the thickness of the flat portion not too thick allows for a wider gap between the flat portion and the absorbent material, which allows bodily fluids to be quickly transferred from the flat portion to that gap. As a result, the liquid drainage of the flat portion, and consequently the top sheet, can be improved. Consequently, the top sheet is less likely to become wet during use, and the user is less likely to experience discomfort. Therefore, by being used as a top sheet for absorbent articles, it is possible to provide an absorbent article that can enhance absorption performance while improving liquid drainage at the top sheet. Furthermore, when this top sheet nonwoven fabric is used as a top sheet for an absorbent article, the recessed and flat areas are easily visible before and after use, making it easier for the user to feel the instantaneous absorption of bodily fluids due to the indented shape of the recessed areas and the diffusion of bodily fluids in the longitudinal / width directions due to the planar shape of the flat areas, thus providing a sense of security.

[0038] Hereinafter, absorbent articles and nonwoven fabrics for top sheets of absorbent articles according to embodiments of the present invention will be described, with pant-type disposable diapers being used as an example of the absorbent article. However, the present invention is not limited to its embodiments and examples, and can be applied to other types of absorbent articles, such as tape-type disposable diapers, urine pads, sanitary napkins, panty liners, and other absorbent articles for absorbing bodily fluids, without departing from the subject matter of the present invention.

[0039] Figures 1 to 3 show a pant-type disposable diaper 1 according to this embodiment. Figure 1 is a plan view showing an unfolded state of an example of the configuration of the disposable diaper 1, and therefore shows a state in which the elastic member is extended and the side seal portion (described later) is not joined. Figure 2 is a cross-sectional view along the longitudinal center line CL (described later) in Figure 1. Figure 3 is a cross-sectional view along the widthwise center line CW (described later) in Figure 1.

[0040] Disposable diaper 1, in the unfolded state shown in Figures 1 to 3, has a longitudinal direction L, a width direction W, and a thickness direction T that are mutually orthogonal. The imaginary line passing through the center of the width direction W of disposable diaper 1 and extending along the longitudinal direction L is called the longitudinal centerline CL, and the width centerline passing through the center of the longitudinal direction L and extending along the width direction W is called the width centerline CW. Here, the direction and side approaching the longitudinal centerline CL are considered the inward and inward directions of the width direction W, respectively, and the direction and side moving away from the width centerline CL are considered the outward and outward directions of the width direction W, respectively. On the other hand, the direction and side approaching the width centerline CW are considered the inward and inward directions of the longitudinal direction L, respectively, and the direction and side moving away from the width centerline CW are considered the outward and outward directions of the longitudinal direction L, respectively. Furthermore, viewing disposable diaper 1 placed on a plane parallel to the plane containing the longitudinal direction L and the width direction W from above the plane in the thickness direction T is called a "planar view," and the shape perceived in a planar view is called the "planar shape." Any direction within a plane including the longitudinal direction L and the width direction W is called the "plane direction". When disposable diaper 1 is worn, the side of the disposable diaper 1 that is relatively closer to the wearer's skin and the side that is farther away from the wearer's skin in the thickness direction T are also called the "skin side" and the "non-skin side", respectively. In disposable diaper 1, the surface that comes into contact with the skin and the surface opposite it are also called the "skin-contact surface" and the "non-skin-contact surface", respectively. In the longitudinal direction L, the side that is relatively closer to the ventral side (described later) or farther away from the dorsal side (described later) is also called the ventral side or anterior side, and the side that is relatively closer to the dorsal side or farther away from the ventral side is also called the dorsal side or posterior side. The above definitions are also applied to each material of disposable diaper 1 and to disposable diaper 1 when it is worn.

[0041] In disposable diapers 1, the statement that its components, structure, and shape are aligned with a predetermined direction (for example, the longitudinal direction L, the width direction W, and the thickness direction T) includes not only cases where the components are parallel to the predetermined direction, but also cases where they are within a range of ±30° with respect to the predetermined direction. For curved or curved components, the components are evaluated as described above with respect to the tangents at each point on the curve.

[0042] The disposable diaper 1 comprises an abdominal portion 3, a dorsal portion 2, and a crotch portion AX. The abdominal portion 3, dorsal portion 2, and crotch portion AX are the parts of the disposable diaper 1 that cover the wearer's abdomen, back, and crotch, respectively, and are connected in the longitudinal direction. In this embodiment, the crotch portion AX is the portion between the abdominal portion 3 and the dorsal portion 2. The disposable diaper 1 further comprises an absorbent body 4 on the skin side of at least the crotch portion AX. The absorbent body 4 is the part of the disposable diaper 1 that generally covers the wearer's crotch, and includes an absorbent material 8. At least the front and rear ends of the absorbent body 4 in the longitudinal direction L extend to the central portion in the width direction W of the abdominal portion 3 and dorsal portion 2, respectively.

[0043] In this embodiment, the absorbent body 4 has at least its front and rear ends in the longitudinal direction L that extend to the central portion in the width direction W of the ventral portion 3 and dorsal portion 2, respectively. The front and rear ends of the absorbent body 4 are connected to the central portion in the width direction W of the ventral portion 3 and dorsal portion 2, respectively, by an adhesive (example: hot melt adhesive, the same applies hereinafter). In this case, the front and rear ends of the absorbent body 4 reach approximately the central portion in the longitudinal direction L of the ventral portion 3 and dorsal portion 2, respectively, but may also reach approximately the outer ends in the longitudinal direction L.

[0044] When the fold line FL, formed by folding the unfolded disposable diaper 1 in half along its longitudinal direction L, is defined as a boundary (virtual), the disposable diaper 1 has, in a plan view, a ventral region FS located ventrally to the longitudinal direction L from the fold line FL (boundary), and a dorsal region BA located dorsally to the longitudinal direction L. The ventral region FS includes the ventral part 3 and approximately half of the front of the crotch part AX (absorbent body 4). The dorsal region BA includes the dorsal part 2 and approximately half of the rear of the crotch part AX (absorbent body 4). In this embodiment, the fold line FL is the widthwise center line CW.

[0045] Disposable diaper 1 is formed by joining together a pair of ventral joining portions 3a located at both ends of the width direction W of the ventral portion 3 and extending along the longitudinal direction L, and a pair of dorsal joining portions 2a located at both ends of the width direction W of the dorsal portion 2 and extending along the longitudinal direction L. When unused, disposable diaper 1 is folded in half along the fold line FL and stored, for example, in a packaging bag. The portion where the pair of ventral joining portions 3a and the pair of dorsal joining portions 2a are joined together is also called a pair of side seal portions. In this case, in disposable diaper 1, the ventral portion 3 and the dorsal portion 2, joined together by the pair of side seal portions, form a waist circumference portion that covers the wearer's waist. In addition, the outer ends of the ventral portion 3 and the dorsal portion 2 in the longitudinal direction L define a waist circumference opening through which the wearer's waist passes. Furthermore, in the disposable diaper 1, the ends on both sides in the width direction W of the absorbent body 4, as well as the inner ends in the longitudinal direction L of the ventral portion 3 and dorsal portion 2, define a pair of leg openings through which the wearer's pair of legs can pass.

[0046] In this embodiment, when unfolded, the ventral portion 3 and the dorsal portion 2 each have a rectangular shape that is generally long in the width direction W, and are spaced apart from each other in the longitudinal direction L. The absorbent body 4 has a rectangular shape that is generally long in the longitudinal direction L, and one end in the longitudinal direction L is connected to the ventral portion 3, and the other end is connected to the dorsal portion 2. The ventral portion 3, the absorbent body 4, and the dorsal portion 2 are formed separately from each other. Therefore, the disposable diaper 1 is a 3-piece type. At least two of the ventral portion 3, the absorbent body 4, and the dorsal portion 2 may be formed as a single unit, or they may be connected as a single unit by another outer sheet or the like. For example, if the ventral portion 3 and the dorsal portion 2 share at least one of the sheet members that make up the ventral portion 3 and the dorsal portion 2, and are formed as a single unit by a continuous sheet member, then the disposable diaper 1 can be said to be a 2-piece type composed of that and the absorbent body 4. A two-piece disposable diaper is a disposable diaper that, when unfolded, has an abdominal section, a crotch section, and a dorsal section, with the abdominal, crotch, and dorsal sections joined together by a single outer covering.

[0047] The ventral portion 3 is formed by laminating an inner sheet member 31 located on the skin side and an outer sheet member 32 located on the non-skin side in the thickness direction T, and joining them with an adhesive or heat seal (hereinafter also simply referred to as "adhesive, etc."). Similarly, the dorsal portion 2 is formed by laminating an inner sheet member 21 located on the skin side and an outer sheet member 22 located on the non-skin side in the thickness direction T, and joining them with an adhesive, etc.

[0048] In this embodiment, the outer sheet member 32 on the non-skin side of the ventral portion 3 has its outer end in the longitudinal direction L folded back towards the skin and overlapping with the inner sheet member 31 on the skin side. In this case, the outer sheet member 32 that has been folded back and is located on the skin side is considered to be the inner sheet member 31. Similarly, in this embodiment, the outer sheet member 22 on the non-skin side of the dorsal portion 2 has its outer end in the longitudinal direction L folded back towards the skin and overlapping with the inner sheet member 21 on the skin side. In this case, the outer sheet member 22 that has been folded back and is located on the skin side is considered to be the inner sheet member 21.

[0049] In this embodiment, the ventral portion 3 and the dorsal portion 2 are joined at multiple locations by adhesive or the like, with inner sheet members 31 and 21 and outer sheet members 32 and 22, respectively. Therefore, adhesive is scattered at multiple locations on the inner sheet members 31 and 21 and outer sheet members 32 and 22, respectively, in the ventral portion 3 and the dorsal portion 2.

[0050] In the ventral portion 3, multiple waist elastic members 13 for waist gathering are arranged between the inner sheet member 31 located on the skin side and the outer sheet member 32 located on the non-skin side. The multiple waist elastic members 13 extend along the width direction W from one end to the other in the width direction W of the ventral portion 3, except for the region that overlaps with the central part of the absorbent body 8 in the thickness direction T, and are spaced apart in the longitudinal direction L. The inner sheet member 31 and the outer sheet member 32 and the multiple waist elastic members 13 are joined together with an adhesive or the like. In the region of the ventral portion 3 that overlaps with the central part of the absorbent body 8 in the thickness direction T, the waist elastic members 13 are present at both ends of the width direction W of the absorbent body 8, but not in the central part of the width direction W of the absorbent body 8. This is to suppress the absorption performance from decreasing due to the absorbent body 8 contracting in the width direction W.

[0051] In the back portion 2, multiple waist elastic members 12 for waist gathering are arranged between the inner sheet member 21 located on the skin side and the outer sheet member 22 located on the non-skin side. The multiple waist elastic members 12 extend along the width direction W from one end to the other in the width direction W of the back portion 2, except for the region that overlaps with the central part of the absorber 8 in the thickness direction T, and are spaced apart in the longitudinal direction L. The inner sheet member 21 and the outer sheet member 22 and the multiple waist elastic members 12 are joined together with an adhesive or the like. In the region of the back portion 2 that overlaps with the central part of the absorber 8 in the thickness direction T, the waist elastic members 12 are present at both ends of the width direction W of the absorber 8, but not in the central part of the width direction W of the absorber 8. This is to suppress the absorption performance from decreasing due to the absorber 8 contracting in the width direction W.

[0052] In this embodiment, the ventral portion 3 may include a ventral cover sheet member 43 positioned on the skin-facing surface so as to cover the ventral end of the absorbent body 4 in the longitudinal direction L from the skin side. The ventral cover sheet member 43 prevents the ventral end of the absorbent body 4 from directly touching the wearer's skin, thereby suppressing skin friction. Similarly, the dorsal portion 2 may include a dorsal cover sheet member 42 positioned on the skin-facing surface so as to cover the dorsal end of the absorbent body 4 in the longitudinal direction L from the skin side. The dorsal cover sheet member 42 prevents the dorsal end of the absorbent body 4 from directly touching the wearer's skin, thereby suppressing skin friction. The ventral cover sheet member 43 and the dorsal cover sheet member 42 are made of the same material as the inner sheet members 31 and 21, for example.

[0053] Multiple waist elastic members 12 and 13 expand and contract the waist area. There are no particular restrictions on the type of elastic member, but examples include thread-like or sheet-like rubber. There are no particular restrictions on the material of each elastic member, but examples include styrene-butadiene rubber and urethane rubber. The characteristics of each elastic member, such as the size of the cross-section (wire diameter, etc.) and the elongation ratio, are appropriately selected according to the magnitude of the tightening force corresponding to the position within the waist WP.

[0054] The sheet materials described above are not particularly limited as long as they can be used for absorbent articles, but examples include liquid-impermeable sheets. Examples of liquid-impermeable sheets include liquid-impermeable nonwoven fabrics, synthetic resin films, and composite sheets thereof. There are no particular restrictions on the type of nonwoven fabric, but examples include meltblown nonwoven fabrics, spunbond nonwoven fabrics, airlaid nonwoven fabrics, and air-through nonwoven fabrics. The materials for the nonwoven fabrics and synthetic resin films of the sheet materials are not particularly limited as long as they can be used for sanitary products, but examples include thermoplastic resins. Examples of thermoplastic resins include polyolefin resins such as polypropylene and polyethylene, polyamide resins such as 6-nylon and 6,6-nylon, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. The basis weight of the nonwoven fabric of the sheet material is, for example, 5 to 100 g / m². 2The amount is preferably 10-50 g / m². 2 The length (thickness) of the sheet member in the thickness direction T is, for example, 0.1 to 5 mm, preferably 0.1 to 2 mm. The sheet members constituting the ventral portion 3 and the dorsal portion 2 may be two sheets, the inner sheet member and the outer sheet member, one sheet, or three or more sheets (not shown). The sheet members do not need to be folded (not shown).

[0055] In this embodiment, the disposable diaper 1 further comprises an outer sheet member 14 that bridges the gap between the ventral portion 3 and the dorsal portion 2. The outer sheet member 14 is a liquid-impermeable sheet member, such as a nonwoven fabric. The outer sheet member 14 is laminated at both ends in the longitudinal direction L to the ventral portion 3 and the dorsal portion 2, respectively, on the skin-side or non-skin-side of the ventral portion 3 and the dorsal portion 2, and joined with an adhesive or the like. In this embodiment, the outer sheet member 14 is laminated to the skin-side of the ventral portion 3 and the dorsal portion 2. The type and material of the nonwoven fabric are as described above.

[0056] The outer sheet member 14 is generally attached to the non-skin side of the absorbent body 4, which is positioned between the ventral portion 3 and the dorsal portion 2, using adhesive or the like, thereby supporting and protecting the absorbent body 4 from the non-skin side. The outer sheet member 14 may be composed of two or more sheet members (not shown). The outer sheet member 14 may completely cover at least one of the width direction W and the longitudinal direction L of the absorbent body 4 (not shown).

[0057] The disposable diaper 1 may further include a sheet-like stretchable member (not shown) that is attached with adhesive to the non-skin side (or skin side) of at least one of the ventral portion 3 and the dorsal portion 2, and that extends along the width direction W and stretches in the width direction W. The sheet-like stretchable member is, for example, a sheet-like member that is stretchable in the width direction W, and functions as a waist gather and / or sweat-absorbing sheet. Examples of the types of sheet-like stretchable members include stretchable nonwoven fabrics that are composites of styrene rubber, olefin rubber, urethane rubber, etc., with nonwoven fabric or paper, etc.

[0058] The absorbent body 4 is located in the center of the width direction W and has a central body portion 10 that extends along the longitudinal direction L, and may further have a pair of leg gather portions 5 located at both ends of the width direction W and extending along the longitudinal direction L. Each of the pair of leg gather portions 5 extends along the longitudinal direction L and has a plurality of leg elastic members 5a that are spaced apart in the width direction W.

[0059] The central part 10 of the main body has a roughly rectangular shape and includes a liquid-permeable top sheet 7, a liquid-impermeable back sheet 9, and an absorbent 8 located between the top sheet 7 and the back sheet 9 that absorbs and retains liquid. The absorbent 8 is joined to the top sheet 7 and the back sheet 9 by adhesive, and the top sheet 7 and the back sheet 9 are joined to each other by adhesive at their peripheral edges. The shape of the central part 10 of the main body is not limited to the above example as long as it is long in the longitudinal direction L, for example, a rectangle with rounded corners, a rectangle with a short side that curves outward, or an hourglass shape.

[0060] Examples of top sheets 7 include liquid-permeable single-layer or multi-layer nonwoven fabrics. Examples of back sheets 9 include liquid-impermeable single-layer or multi-layer nonwoven fabrics, synthetic resin films, and composite sheets thereof. There are no particular restrictions on the type of nonwoven fabric, and examples include meltblown nonwoven fabrics, spunbond nonwoven fabrics, airlaid nonwoven fabrics, air-through nonwoven fabrics, and spunlace nonwoven fabrics. There are no particular restrictions on the type of synthetic resin film, and known film materials can be used. There are no particular restrictions on the material of the nonwoven fabric or synthetic resin film as long as it can be used for sanitary products, but examples include thermoplastic resins. Examples of thermoplastic resins include olefin resins such as polyethylene and polypropylene, polyamide resins such as 6-nylon and 6,6-nylon, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. These resins may be used alone or in combination of two or more types of resins. Furthermore, the structure of the fibers constituting the nonwoven fabric is not particularly limited. Examples include core-sheath fibers, side-by-side fibers, island / sea fibers, and other composite fibers; hollow fibers; flat, Y-shaped, C-shaped fibers; three-dimensional crimped fibers with latent or apparent crimping; and split fibers that are divided by physical loads such as water flow, heat, or embossing. These fibers may be used individually or in combination of two or more types. In this embodiment, the fibers constituting the nonwoven fabric are heat-fusible fibers, specifically composite core-sheath fibers with polyethylene terephthalate as the core and polyethylene as the sheath. Cellulose fibers, semi-synthetic fibers such as acetate, and regenerated fibers such as rayon may be mixed as the material for the nonwoven fabric. To provide breathability, the synthetic resin film may contain inorganic particles such as calcium carbonate. The basis weight of the top sheet 7 is, for example, 5 to 500 g / m². 2 These include 10-100g / m². 2 Preferably, 20-50 g / m 2 This is preferable.

[0061] The absorbent body 8 includes an absorbent core 8b that absorbs and retains liquid, and a core wrap 8a that encloses the absorbent core 8b, and may include grooves that allow the liquid to diffuse in the longitudinal direction L and the width direction W. As the material of the absorbent core 8b, at least one of an absorbent material, such as a cellulose fiber and a superabsorbent polymer, can be used. Examples of cellulose fibers include natural cellulose fibers such as wood pulp fibers, cross-linked pulp fibers, and non-wood pulp fibers, as well as regenerated cellulose fibers and semi-synthetic cellulose fibers. In the case of pulp fibers, the average major diameter of the fibers is, for example, several tens of μm, preferably 20 to 40 μm, and the average fiber length is, for example, several millimeters, preferably 2 to 5 mm. Examples of superabsorbent polymers (SAP) include polyacrylate-based, polysulfonate-based, and maleate anhydride-based superabsorbent polymers. As the size (when dry) of the superabsorbent polymer, the average particle size is, for example, several hundred μm, preferably 200 to 500 μm. For example, the basis weight of the cellulose fibers and superabsorbent polymers is 100 to 400 g / m², respectively. 2 Examples include liquid-permeable sheets such as nonwoven fabric or tissue paper, which can be used as materials for Corewrap 8a.

[0062] The central part 10 of the main body is provided with a pair of leak-proof walls 6 arranged facing each other on both sides in the width direction W and extending along the longitudinal direction L. Each leak-proof wall 6 is formed of a leak-proof sheet member 6b that extends along the longitudinal direction L and contains a plurality of leak-proof elastic members 6a arranged at intervals in the width direction W. The outer end of each leak-proof wall 6 in the width direction W is joined to at least one of the top sheet 7, absorbent 8, and back sheet 9 with an adhesive or the like to form a fixed end, and the inner end in the width direction W is spaced apart from the other sheets, including the top sheet 7, to form a free end. The plurality of leak-proof elastic members 6a are joined with an adhesive near the free ends of the leak-proof sheet member 6b. Examples of leak-proof sheet members 6b include hydrophobic sheet members, and examples of hydrophobic sheet members include nonwoven fabrics containing thermoplastic resin fibers. The type and material of the nonwoven fabric are, for example, the same as in the case of the inner sheet members 31 and 21 described above. Multiple leak-proof elastic members 6a are exemplified by rubber threads, but the type and material of the elastic members are as described above. The characteristics of the elastic members, such as the size of the cross-section (wire diameter, etc.) and the elongation ratio, are appropriately selected according to the function of the leak-proof wall 6. Note that each leak-proof wall 6 may have its inner end in the width direction W folded back to the outside in the width direction W.

[0063] A pair of leg gather sections 5 are joined to both ends of the main body central section 10 in the width direction W. Each leg gather section 5 extends along the longitudinal direction L and comprises a plurality of leg elastic members 5a arranged at intervals in the width direction W, and a skin-side and a non-skin-side leg sheet member 5b that sandwiches the plurality of leg elastic members 5a. The inner end of each leg gather section 5 in the width direction W is joined to the non-skin-side surface of the end of the main body central section 10 in the width direction W with adhesive to form a fixed end, and the outer end in the width direction W is spaced apart from the main body central section 10 to form a free end. The plurality of leg elastic members 5a are joined with adhesive near the free ends of the skin-side and non-skin-side leg sheet members 5b. The plurality of leg elastic members 5a cause each leg gather section 5 to expand and contract. Examples of leg sheet members 5b include hydrophobic sheet members, and examples of hydrophobic sheet members include nonwoven fabrics containing thermoplastic fibers. The type and material of the nonwoven fabric are as described above. The multiple leg elastic members 5a are exemplified by elastic threads, and the type and material of these elastic members are as described above. The characteristics of the elastic members, such as the size of the cross-section (linearity, etc.) and the elongation ratio of the elastic members, are appropriately selected according to the magnitude of the tightening force corresponding to the position within the leg gather portion 5.

[0064] In the disposable diaper 1, a pair of leg gathers 5 are bridged by an outer sheet member 14. The outer sheet member 14 is laminated at both ends in the width direction W to the inner ends in the width direction W of each of the pair of leg gathers 5 and joined with an adhesive or the like, thus supporting and protecting the pair of leg gathers 5 from the non-skin side. The pair of leg gathers 5 may be formed integrally with the outer sheet member 14.

[0065] The dorsal portion 2 may include a dorsal extension that extends further inward from the inner edge in the longitudinal direction L of the dorsal main body portion, which occupies substantially the same area as the dorsal joint portion 2a in the longitudinal direction L. The dorsal extension is the inner region of the dorsal portion 2 in the longitudinal direction L. The portion of the dorsal extension that does not overlap with the absorbent main body 4, i.e., the portions on both sides in the width direction W, functions as a pair of buttock cover portions 40. The buttock cover portions 40 protect the wearer's buttocks from the outside. The buttock cover portions 40 include a buttock elastic member 41 that deforms the buttock cover portions 40 to conform to the wearer's buttocks.

[0066] Next, the nonwoven fabric for the top sheet of the absorbent article according to this embodiment will be described. Figures 4 and 5 show the top sheet 7 when the nonwoven fabric for the top sheet according to this embodiment is applied to the disposable diaper 1. Figure 4 is a schematic plan view showing an example of the configuration of the top sheet 7. Figure 5(a) is a cross-sectional view along the line Va-Va in Figure 4, and Figure 5(b) is a cross-sectional view along Vb-Vb in Figure 4.

[0067] The top sheet 7 comprises a skin-side surface Q1 (first surface) located on the skin side, and a non-skin-side surface Q2 (second surface) which is the back surface of the skin-side surface Q1 (first surface) and located on the non-skin side, and includes a flat portion 51 and a plurality of recesses 52.

[0068] The flat portion 51 is the part that comes into contact with the skin on the skin side Q1. The flat portion 51 is the flat portion of the top sheet 7 excluding the recesses 52. The degree of unevenness in the flat portion 51 is preferably less than or equal to the thickness of the flat portion 51. In this embodiment, the flat portion 51 includes a plurality of longitudinal flat portions 51a and a plurality of widthwise flat portions 51b. The plurality of longitudinal flat portions 51a extend along the longitudinal direction L and are spaced apart in the width direction W. The longitudinal flat portions 51a are substantially strip-shaped portions that extend along the longitudinal direction L. Between adjacent longitudinal flat portions 51a in the width direction W, a row of a plurality of recesses 52 are arranged spaced apart along the longitudinal direction L. On the other hand, the plurality of widthwise flat portions 51b are arranged between adjacent longitudinal flat portions 51a of the plurality of longitudinal flat portions 51a, extend along the width direction W, and are spaced apart in the longitudinal direction L. The widthwise flat portion 51b is a roughly rectangular portion that bridges the longitudinal flat portion 51a in the widthwise direction W. A recess 52 is positioned between adjacent widthwise flat portions 51b in the longitudinal direction L.

[0069] The multiple recesses 52 are recesses that extend from the skin-facing surface (skin-facing side Q1 (first surface)) of the flat portion 51 toward the absorbent 8, and therefore extend from the skin-facing side Q1 toward the non-skin-facing side Q2. The shape of each of the multiple recesses 52 in plan view is not particularly limited, but a shape that is long in the longitudinal direction L is preferred, and examples include an ellipse, oblong, rectangle, rounded rectangle, oval, polygon, etc., that are long in the longitudinal direction L. In this embodiment, the shape of the recess 52 in plan view is a rounded rectangle. Each of the multiple recesses 52 includes a bottom surface BS that is in contact with the absorbent 8, and a peripheral wall SW that extends from the periphery of the bottom surface BS toward the flat portion 51. In Figure 5, it is shown that there is a portion of the bottom surface BS that is not in contact with the absorbent 8 near the portion that is joined to the absorbent 8 via adhesive AD, but most of the bottom surface BS, which is not shown, is in contact with the absorbent 8.

[0070] One of the thicknesses dT1 of the flat portion 51 (the thickness dT1a of the longitudinally flat portion 51a and the thickness dT1b of the widthwise flat portion 51b) and the thickness dT2 of the bottom portion BS is 0.7 to 1.3 times, preferably 0.8 to 1.2 times, of the other. That is, the thickness dT1 of the flat portion 51 and the thickness dT2 of the bottom portion BS are approximately the same thickness. In this embodiment, the thickness dT1 of the flat portion 51 and the thickness dT2 of the bottom portion BS of the top sheet 7 can be, for example, 0.05 to 3 mm, preferably 0.08 to 2 mm, and more preferably 0.1 to 1.5 mm, from the viewpoint of the strength and liquid permeability of the top sheet 7.

[0071] <Method for measuring the thickness of nonwoven fabric> (1) When the nonwoven fabric is laid flat, the length direction is Y and the width direction is X. A predetermined position in the nonwoven fabric in the length direction Y and width direction X (for example, the center) is cut parallel to the length direction Y and width direction X to obtain a test piece measuring 30 mm (length direction Y) × 10 mm (width direction X). However, the length direction Y and the width direction X correspond to the longitudinal direction L and the width direction W, respectively. (2) Let Z be the thickness direction perpendicular to the length direction Y and the width direction X. Position the test specimen upright so that the cross-section of the specimen described in (1) above can be observed. When positioning the specimen upright, it may be sandwiched between rectangular prisms or the like (for example, a block of rectangular prisms) without crushing it. When measuring the cross-section in the X direction (cross-section viewed from the X direction) while the specimen is upright, the measurement range will be Y: 30 mm, Z: 10 mm. When measuring the cross-section in the Y direction (cross-section viewed from the Y direction), the measurement range will be X: 10 mm, Z: 10 mm. (3) Prepare a digital microscope VHX-7000 (manufactured by KEYENCE) as the measuring instrument, adjust the position of the test specimen so that the lens is directly above the cut surface of the specimen, and perform observation and measurement. (4) Measurement mode: Measurement scale → Planar measurement → Main measurement → Two-point measurement to measure the length between one edge and the other edge of the cross section. The measurement is performed 10 minutes after cutting in a 25°C atmosphere. (5) Perform steps (1) to (4) above on three test specimens, calculate the average value, and use that as the thickness.

[0072] As described above, in the disposable diaper 1 according to this embodiment, when the nonwoven fabric for the top sheet according to this embodiment is applied to the top sheet 7, the bottom surface BS of each of the multiple recesses 52 is in contact with the absorbent material 8. Therefore, bodily fluids can be quickly transferred from each of the multiple recesses 52 to the absorbent material 8 via the bottom surface BS. As a result, the absorbent material 8 can quickly absorb bodily fluids.

[0073] Furthermore, the thickness dT1 (dT1a, dT1b) of the flat portion 51 that comes into contact with the skin is approximately the same as (0.7 to 1.3 times) the thickness dT2 of the bottom portion BS that comes into contact with the absorbent 8, and is not too thick. In this way, by not having too thick a thickness dT1 of the flat portion 51, the amount of liquid temporarily held in the flat portion 51 can be reduced. In addition, by not having too thick a thickness dT1 of the flat portion 51, the gap VA between the flat portion 51 and the absorbent 8 can be widened, thereby allowing bodily fluids to be quickly transferred from the flat portion 51 to the gap VA. As a result, the liquid drainage of the flat portion 51, and consequently the top sheet 7, can be improved. Consequently, the top sheet 7 is less likely to become wet during use, and the user is less likely to experience discomfort.

[0074] Therefore, by applying the nonwoven fabric for the top sheet according to this embodiment to the top sheet 7, it is possible to provide a disposable diaper 1 according to this embodiment that can improve the absorption performance while enhancing the liquid drainage of the top sheet 7. Furthermore, because the recessed portion 52 and the flat portion 51 are easily visible before and after use, the user can easily feel the instantaneous absorption of bodily fluids due to the indenting shape of the recessed portion 52 and the diffusion of bodily fluids in the longitudinal direction L / width direction W due to the planar shape of the flat portion 51, and thus feel more secure.

[0075] Of the flat portion 51, the length (width) dW1 in the width direction W of the longitudinal flat portion 51a can be, for example, 0.3 to 5 mm, preferably 0.5 to 4 mm, and more preferably 0.7 to 3 mm. Here, the length (width) dW1 in the width direction W of the longitudinal flat portion 51a refers to the shortest distance (dP1: described later) between adjacent recesses 52 in the width direction W. If the length (width) dW1 in the width direction W of the longitudinal flat portion 51a is 0.3 mm or more, the width of the longitudinal flat portion 51a becomes wider, and the diffusion of bodily fluids in the longitudinal direction L increases. If it is 5 mm or less, the number of recesses 52 increases, and the diffusion of bodily fluids downward through the recesses 52 increases, making it easier to obtain the effects described above. In this embodiment, it is approximately 1.5 mm. The length in the longitudinal direction L of the longitudinal flat portion 51a can be, for example, the length in the longitudinal direction L of the absorbent 8, and may be greater than or equal to that.

[0076] <Methods for measuring width, length, and distance> (1) Place the nonwoven fabric on the measuring table so that its surface can be observed. (2) A digital microscope VHX-7000 (manufactured by KEYENCE) was prepared as the measuring instrument, and measurements were performed using the measurement modes: Depth Up → Live Depth Synthesis → Automatic Synthesis mode, to obtain 2D data in which the color differs depending on the depth of the nonwoven fabric. (3) For the obtained 2D data, identify the ends of shapes with the same depth (e.g., ellipses), and measure the distance (width, length) between the ends using the measurement mode: Measurement / Scale → Planar Measurement → Main Measurement → Measurement between Two Points. (4) Perform steps (1) to (3) above on three test specimens, calculate the average value, and use it as the distance (width, length) between the ends.

[0077] Of the flat portion 51, the length (width) dL1 in the longitudinal direction L of the widthwise flat portion 51b can be, for example, 0.2 to 4 mm, preferably 0.4 to 3 mm, and more preferably 0.6 to 2 mm. Here, the length (width) dL1 in the longitudinal direction L of the widthwise flat portion 51b refers to the shortest distance (dP2: described later) between adjacent recesses 52 in the longitudinal direction L. If the length (width) dL1 in the longitudinal direction L of the widthwise flat portion 51b is 0.2 mm or more, the width of the widthwise flat portion 51b becomes wider, and the diffusion of bodily fluids in the widthwise direction W increases. If it is 4 mm or less, the number of recesses 52 increases, and the diffusion of bodily fluids downward through the recesses 52 increases, making it easier to obtain the effects described above. In this embodiment, it is approximately 1.3 mm. The length in the widthwise direction W of the widthwise flat portion 51b is the same as the length (width) dW2 of the recesses 52 in the widthwise direction.

[0078] Among the flat portions 51, the distance dH between adjacent longitudinal flat portions 51a in the width direction W can be, for example, 0.55 to 10 mm, preferably 0.85 to 8 mm, and more preferably 1.2 to 6 mm. Here, the distance dH between adjacent longitudinal flat portions 51a refers to the distance between the approximate center positions in the width direction W of each longitudinal flat portion 51a. If the distance dH between adjacent longitudinal flat portions 51a is 0.55 mm or more, the gap between the flat portion 51 and the recess 52 will not become too narrow, and if it is 10 mm or less, the gap between the flat portion 51 and the recess 52 will not become too wide, making it easier to obtain the effects described above. In this embodiment, it is approximately 3.5 mm.

[0079] In a preferred embodiment of this disposable diaper 1, as described above, the flat portion 51 includes a plurality of longitudinal flat portions 51a and a plurality of widthwise flat portions 51b. That is, the longitudinal flat portions 51a form a continuous straight path in the longitudinal direction L. On the other hand, the widthwise flat portions 51b are blocked by the longitudinal flat portions 51a and form a discontinuous straight path, i.e., a zigzag path, in the widthwise direction W. Therefore, bodily fluids can easily diffuse quickly in the longitudinal direction L along the longitudinal flat portions 51a. Thus, bodily fluids can be quickly spread over a wide area in the longitudinal direction L of the absorbent material 8 and absorbed quickly. On the other hand, when bodily fluids diffuse along the widthwise flat portions 51b, their progress is easily slowed by the longitudinal flat portions 51a, and they tend to turn towards the longitudinal direction L midway. Therefore, the absorbent material 8 can be used to absorb body fluids over a wide area in the width direction W, while preventing leakage of body fluids from the edges in the width direction W (lateral leakage). Thus, since the absorbent material 8 can be used over a wide area while lateral leakage is suppressed, the absorption performance can be further improved.

[0080] The depth Dp2 of the recess 52 can be, for example, 0.25 to 5 mm, preferably 0.5 to 3 mm, and more preferably 0.75 to 2 mm. Here, the depth Dp2 of the recess 52 refers to the depth from the highest point on the adjacent longitudinal flat portion 51a (skin side Q1 of the nonwoven fabric) to the deepest point on the bottom portion BS (skin side Q1 of the nonwoven fabric). If the depth Dp2 is 0.25 mm or more, the recess 52 is not too shallow, and bodily fluids are less likely to overflow from the recess 52. If the depth Dp2 is 5 mm or less, the recess 52 is not too deep, the recess 52 does not retain too much bodily fluid, and the bodily fluids can be dispersed to the flat portion 51 and diffused in the longitudinal direction L, making it easier to obtain the effects described above. In this embodiment, it is approximately 1.2 mm.

[0081] The length dL2 of the longitudinal direction L of the recess 52 can be, for example, 0.5 to 10 mm, preferably 0.75 to 8 mm, and more preferably 1 to 6 mm. Here, the length dL2 of the longitudinal direction L of the recess 52 refers to the longest length in the longitudinal direction L of the recess 52. If the length dL2 of the longitudinal direction L of the recess 52 is 0.5 mm or more, the recess 52 is not too small, and bodily fluids are less likely to overflow from the recess 52. If it is 10 mm or less, the recess 52 is not too large, and bodily fluids can be dispersed to the flat portion 51 and diffused in the longitudinal direction L more easily, making it easier to obtain the effects described above. In this embodiment, it is approximately 4.0 mm.

[0082] On the other hand, the length dW2 in the width direction W of the recess 52 can be, for example, 0.25 to 5 mm, preferably 0.35 to 4 mm, and more preferably 0.5 to 3 mm. Here, the length dW2 in the width direction W of the recess 52 refers to the longest length in the width direction W of the recess 52. If the length dW2 in the width direction W of the recess 52 is 0.25 mm or more, the recess 52 is not too small, and bodily fluids are less likely to overflow from the recess 52. If it is 5 mm or less, the recess 52 is not too large, and bodily fluids can be dispersed into the flat portion 51 and diffused in the longitudinal direction L, making it easier to obtain the effects described above. In this embodiment, it is approximately 2.2 mm.

[0083] In a preferred embodiment of this disposable diaper 1, each of the multiple recesses 52 has a length dL2 in the longitudinal direction L that is longer than the length dW2 in the width direction W when viewed from above. This allows the flat portions 51 (longitudinal flat portions 51a) that exist between adjacent recesses 52 in the width direction W to be relatively long in the longitudinal direction L. As a result, bodily fluids can quickly diffuse in the longitudinal direction L along the portions of the flat portions 51 that are relatively long in the longitudinal direction L (longitudinal flat portions 51a). Therefore, bodily fluids can be quickly spread over a wide area in the longitudinal direction L of the absorbent material 8 and quickly absorbed. This further enhances the absorption performance.

[0084] In a preferred embodiment of this disposable diaper 1, the shortest distance dP1 between adjacent recesses 52 in the width direction W in each of the plurality of recesses 52 is greater than the shortest distance dP2 between adjacent recesses 52 in the longitudinal direction L in each of the plurality of recesses 52 (dP1 > dP2). In other words, in the flat portion 51, the portion that exists between adjacent recesses 52 in the width direction W and extends in the longitudinal direction L (longitudinal flat portion 51a) is relatively thick, and the portion that exists between adjacent recesses 52 in the longitudinal direction L and extends in the width direction W (widthwise flat portion 51b) is relatively thin.

[0085] The shortest distance dP1 between adjacent recesses 52 in the width direction W can be, for example, 0.3 to 5 mm, preferably 0.5 to 4 mm, and more preferably 0.7 to 3 mm. If the shortest distance dP1 is 0.3 mm or more, the width of the longitudinally flat portion 51a increases, and the diffusion of bodily fluids in the longitudinal direction L increases. If it is 5 mm or less, the number of recesses 52 increases, and the diffusion of bodily fluids downward through the recesses 52 increases, making it easier to obtain the effects described above. In this embodiment, it is approximately 1.5 mm.

[0086] On the other hand, the shortest distance dP2 between adjacent recesses 52 in the longitudinal direction L can be, for example, 0.2 to 4 mm, preferably 0.4 to 3 mm, and more preferably 0.6 to 2 mm. If the shortest distance dP2 is 0.2 mm or more, the width of the widthwise flat portion 51b becomes wider, and the diffusion of bodily fluids in the widthwise direction W increases. If it is 4 mm or less, the number of recesses 52 increases, and the diffusion of bodily fluids downward through the recesses 52 increases, making it easier to obtain the effects described above. In this embodiment, it is approximately 1.3 mm.

[0087] Thus, because the longitudinally flat portion 51a is relatively thick and the widthwise flat portion 51b is relatively thin, body fluids can easily diffuse quickly in the longitudinal direction L along the relatively thicker longitudinally flat portion 51a of the flat portion 51. Therefore, body fluids can be quickly distributed over a wide area in the longitudinal direction L of the absorbent 8 and absorbed quickly. This further enhances the absorption performance.

[0088] Furthermore, the presence of flat portions 51 (widthwise flat portions 51b) on both sides of the longitudinal direction L of the recess 52 allows for a certain degree of diffusion of body fluids in the widthwise direction W compared to the case where the recess 52 is continuous in the longitudinal direction L. Therefore, the absorbent material 8 can be used for absorbing body fluids not only over a wide area in its longitudinal direction L but also over a wide area in the widthwise direction W. This further enhances the absorption performance.

[0089] In a preferred embodiment of this disposable diaper 1, the length dW2 in the width direction W of each of the multiple recesses 52 is longer than the shortest distance dP1 between adjacent recesses 52 in the width direction W of each of the multiple recesses 52. Therefore, the length dW2 in the width direction W of the recess 52 is longer than the length (width) dW1 of the length W of the longitudinal flat portion 51a.

[0090] Therefore, when bodily fluids excreted on the top sheet 7 diffuse in the width direction W, they are more easily captured by one of the recesses 52. Consequently, bodily fluids are drawn into one of the recesses 52 without leaking out from the edges in the width direction W (lateral leakage) and are reliably absorbed into the absorbent material. This allows for rapid and reliable absorption of bodily fluids in multiple recesses, thereby further enhancing absorption performance.

[0091] In a preferred embodiment of this disposable diaper 1, the thickness dsw of the peripheral wall SW gradually decreases from the flat portion 51 side toward the bottom portion BS side. For example, the thickness dT1 of the flat portion 51 (the thickness dT1a of the longitudinally flat portion 51a and the thickness dT1b of the widthwise flat portion 51b) and the thickness dT2 of the bottom portion BS are approximately the same, but the thickness dT1 of the flat portion 51 is made slightly thicker than the thickness dT2 of the bottom portion BS. As a result, in the peripheral wall SW located between the slightly thicker flat portion 51 and the slightly thinner bottom portion BS, the thickness dsw gradually decreases from the flat portion 51 side toward the bottom portion BS side.

[0092] Therefore, the fiber density of the peripheral wall SW gradually increases from the flat portion 51 side toward the bottom portion BS side. Consequently, it is possible to suppress the flow of bodily fluids in the recesses 52 toward the flat portion 51 side, that is, the flow of bodily fluids in the reverse direction. This makes it easier for bodily fluids stored in each of the multiple recesses 52 to be transferred to the absorbent 8, thereby improving the absorption performance.

[0093] In a preferred embodiment of this disposable diaper 1, the thickness dsw1 of the portion of the peripheral wall SW adjacent to the flat portion 51 is smaller than the thickness dT1 (dT1a, dT1b) of the flat portion 51. For example, as described above, the thickness dT1 of the flat portion 51 is made slightly thicker than the thickness dT2 of the bottom portion BS. Consequently, the fiber density of the portion of the peripheral wall SW adjacent to the flat portion 51 becomes higher than that of the flat portion 51.

[0094] Therefore, bodily fluids in the flat portion 51 are more easily transferred to the peripheral wall portion SW (relatively high fiber density). This prevents the flat portion from retaining bodily fluids. Furthermore, the bodily fluids stored in the flat portion are transferred to the space between the flat portion and the absorbent, and also to the bottom portion via the peripheral wall portion of the recess, both of which are more easily transferred to the absorbent. Consequently, the absorption performance can be further enhanced.

[0095] In a preferred embodiment of this disposable diaper 1, the area ratio of the multiple recesses 52 on the top sheet 7 is greater than the area ratio of the flat portions 51 on the top sheet 7. For example, the area ratio of the multiple recesses 52 on the top sheet 7 can be 51 to 90%, preferably 51 to 85%, and more preferably 53 to 80%. The remaining area ratio is the area ratio of the flat portions 51 on the top sheet 7.

[0096] <Method for measuring area> (1) Place the nonwoven fabric on the measuring table so that its surface can be observed. (2) A digital microscope VHX-7000 (manufactured by KEYENCE) was prepared as the measuring instrument, and measurements were performed using the measurement modes: Depth Up → Live Depth Synthesis → Automatic Synthesis mode, to obtain 2D data in which the color differs depending on the depth of the nonwoven fabric. (3) For the obtained 2D data, the area of ​​the recess is obtained by individually measuring the periphery of the ellipse with the same depth using the measurement mode: Measurement / Scale → Planar Measurement → Area Measurement → Specify Shape and Measure Area → Specify with Free Line. (Area of ​​recess 52) (4) For the obtained 2D data, the measurement mode is: Measurement / Scale → Planar Measurement → Area Measurement → Specify the shape and measure the area → Specify a repeating pattern of concave and flat areas using a rectangle, and perform individual measurements to obtain the area of ​​the repeating pattern including the concave and flat areas. (Area of ​​the repeating pattern) (5) The area of ​​the flat portion is obtained by [Area of ​​repeating pattern] - [Area of ​​concave portion] = [Area of ​​convex portion]. (Area of ​​flat portion 51)

[0097] Therefore, the area of ​​the recess 52 (the bottom surface BS) that contacts the absorbent material 8 is also large. As a result, even if there is a large amount of bodily fluid, the fluid can be quickly transferred to the absorbent material 8 via the recess 52, ensuring absorption performance. In addition, because the recess 52 is easily visible before and after use, the user can more easily feel the instantaneous absorption of bodily fluid due to the retractable shape of the recess 52, and feel more secure.

[0098] In a preferred embodiment of this disposable diaper 1, the distance dTA (dTAa, dTAb) between the flat portion 51 (longitudinal flat portion 51a, widthwise flat portion 51b) and the absorbent material 8 is longer than the distance dT2B between the bottom portion BS and the absorbent material 8. Therefore, since the gap VA between the flat portion 51 and the absorbent material 8 is wide, bodily fluids can be transferred to the gap VA more quickly through the flat portion 51. This improves the drainage of liquids in the flat portion 51 and, consequently, in the top sheet 7. Also, when excrement excreted on the top sheet 7 is being absorbed by the absorbent material 8, the color of the excrement is less visible in the flat portion 51 compared to the recess 52 because of its high drainage. This makes it easier for the user to feel dry and secure.

[0099] In a preferred embodiment of this design, the disposable diaper 1 has openings in the flat portion 51 (longitudinal flat portion 51a, widthwise flat portion 51b) or in a plurality of recesses 52 (bottom portion BS, peripheral wall portion SW). However, the size of the openings, in terms of the diameter of the smallest circle surrounding the opening, can be, for example, 0.01 to 0.2 mm, preferably 0.02 to 0.15 mm, and more preferably 0.05 to 0.1 mm. If the size of the opening (diameter of the smallest circle) is 0.01 mm or larger, viscous bodily fluids can be easily transferred to the absorbent material through the opening, and if it is 0.2 mm or smaller, the opening is not too large, making it easier to maintain the strength of the top sheet 7.

[0100] In this disposable diaper 1, by having openings in the flat portion 51 or multiple recesses 52, bodily fluids with a certain degree of viscosity can be absorbed well through these openings. This further enhances the absorbency performance of the disposable diaper 1.

[0101] In another embodiment of this design, the disposable diaper 1 may further include a material (not shown) adjacent to the non-skin side of the top sheet 7. An example of this material is a liquid-permeable second sheet. The color of the top sheet 7 differs from the color of the material. Examples of colors include red, orange, pink, yellow, green, sky blue, blue, purple, black, gray, white, and mixtures of these colors. The colors of the top sheet 7 and the adjacent material are preferably colors that are one or more colors apart on the Ostwald color circle (not shown), preferably two or more colors apart, and preferably three or more colors apart.

[0102] In that case, the color of the adjacent material (not shown) viewed through the flat portion 51 of the top sheet 7 and the color of the adjacent material (not shown) viewed through the recess 52 appear to be different. Therefore, the flat portion 51 and the recess 52 can be easily seen. As a result, the user can more easily perceive the instantaneous absorption of bodily fluids due to the indenting shape of the recess 52 and the rapid diffusion of bodily fluids in the longitudinal direction L / width direction W due to the planar shape of the flat portion 51, and thus feel more secure.

[0103] In a preferred embodiment of this design, the disposable diaper 1 further comprises a material placed on the non-skin side of the absorbent material 8 and a packaging bag that encloses the disposable diaper 1. A pattern design including the flat portion 51 and a plurality of recesses 52 of the top sheet 7 is depicted on at least one of the non-skin side surface of the material and the outer surface of the packaging bag. Examples of patterns include a part or all of the top sheet 7 as seen in plan, as shown in Figure 4, perspective views thereof, and stylized versions thereof.

[0104] However, the material placed on the non-skin side of the absorbent body 8 may include, for example, at least one of the inner sheet member 21 and outer sheet member 22 of the dorsal portion 2, and the inner sheet member 31 and outer sheet member 32 of the ventral portion 3. Furthermore, the packaging bag (not shown) for wrapping the disposable diaper 1 may include, for example, at least one of an individual packaging bag for individually packaging a disposable diaper 1, and a packaging bag for packaging multiple disposable diapers 1 together. The material for the packaging bag may include, for example, a sheet member made of a synthetic resin such as polyethylene, polypropylene, polyethylene terephthalate, or ethylene vinyl alcohol copolymer resin.

[0105] As a result, during a series of actions such as purchasing the product, using the product, and disposing of the product, the user can recognize the pattern including the flat portion 51 and recessed portion 52 of the top sheet 7 through the appearance of the packaging bag, the appearance of the absorbent material, and the surface of the top sheet 7. This allows the user to recognize the instantaneous absorption of bodily fluids due to the indenting shape of the recessed portion 52 and the rapid diffusion of bodily fluids in the longitudinal direction L / width direction W due to the planar shape of the flat portion 51 even before using the absorbent material, making it easier for the user to perceive and feel more secure.

[0106] The nonwoven fabric for the top sheet according to this embodiment, and therefore the method for manufacturing the top sheet 7, is not particularly limited, but for example, it may be manufactured by the following method.

[0107] The manufacturing apparatus for producing top sheet 7 includes a preheating device and a shaping device. The preheating device includes a pair of heating rolls. The preheating device heats the nonwoven fabric to be processed by wrapping it around a rotating lower heating roll, then passes it to a rotating upper heating roll, which further heats the nonwoven fabric to be processed.

[0108] As shown in Figure 6, the shaping device comprises a pair of upper and lower stretching rolls 63 and 64. The shaping device shapes the heated nonwoven fabric 60 to be processed to form flat sections 51 and recesses 52. Specifically, the stretching roll 63 has multiple rows of ridges 63a arranged parallel to each other along its outer circumferential surface, and multiple rows of grooves 63b provided between adjacent ridges 63a, arranged at regular intervals in the roll width direction (left-right direction in the figure). On the other hand, the stretching roll 64 has multiple pins 64a on its outer circumferential surface that interlock with the grooves 63b of the stretching roll 63. These pins 64a are arranged at regular intervals in the roll width direction (left-right direction in the figure) so as not to contact the ridges 63a of the stretching roll 63, and are arranged substantially linearly at regular intervals along the outer circumferential surface in the circumferential direction of the roll. Furthermore, the multiple pins 64a of the stretching roll 64 are arranged in a staggered pattern on its circumferential surface.

[0109] A method for manufacturing a nonwoven fabric for a top sheet, and therefore a top sheet 7, using the above-described manufacturing apparatus, comprises a preheating step of applying preheat to the nonwoven fabric 60 to be processed, and a shaping step of stretching and shaping the nonwoven fabric 60 that has undergone the preheating step.

[0110] The preheating process involves sequentially bringing the nonwoven fabric 60 to be processed, which has been conveyed along the conveying direction, into contact with the outer surfaces of a pair of rotating heating rolls of a preheating device, thereby preheating it. The preheating temperature depends on the type of synthetic resin fiber that makes up the nonwoven fabric 60 to be processed, but for example, in the case of a core-sheath type composite fiber of polyethylene terephthalate (PET) and high-density polyethylene (HDPE), it is preferable that the temperature of the outer surface of the heating rolls be around 60 to 120°C.

[0111] In the shaping process, the nonwoven fabric 60 to be processed, which has been transported after the preheating process, is placed in the shaping device between a pair of interlocking stretching rolls 63 and 64, and the nonwoven fabric 60 is stretched and shaped between the protruding ridges 63a and recessed grooves 63b of the interlocking stretching roll 63 and the pins 64a of the stretching roll 64. When performing the shaping process, it is preferable to heat the stretching rolls 63 and 64 to 60-120°C to facilitate shaping.

[0112] At this time, the stretching roll 63 pushes the portion of the protruding ridge 63a that is in contact with the nonwoven fabric 60 to be processed in the direction of the stretching roll 64, thereby forming a flat portion 51. Meanwhile, the stretching roll 64 pushes the portions of the multiple pins 64a that are in contact with the nonwoven fabric 60 to be processed into the grooves 63b of the stretching roll 63, thereby forming multiple recesses 52. At this time, the portion of the nonwoven fabric 60 to be processed that was in contact with the tip portions of the pins 64a is formed into the bottom surface BS of the recesses 52.

[0113] Furthermore, when openings are made in the nonwoven fabric 60 to be processed, the tension generated when the protrusions 63a and pins 64a are pressed into the nonwoven fabric 60 during the shaping process causes some of the constituent fibers of the nonwoven fabric 60 to be separated or broken. Openings can be made more easily created by reducing the basis weight of the nonwoven fabric 60 to be processed.

[0114] The nonwoven fabric after the shaping process is complete can be used as a top sheet nonwoven fabric including a flat portion 51 and a recessed portion 52, and therefore as a top sheet 7.

[0115] The absorbent articles and nonwoven fabrics for top sheets of absorbent articles of the present invention are not limited to the embodiments described above, and appropriate combinations and modifications of the technologies described in the embodiments and known technologies are possible without departing from the purpose and spirit of the present invention. [Explanation of Symbols]

[0116] 1. Absorbent items (disposable diapers) 7 Top Sheet 8 Absorbent 51 Flat area 52 recess BS bottom part SW peripheral wall

Claims

1. An absorbent article having a longitudinal direction, a width direction and a thickness direction, comprising a top sheet and an absorbent material located on the non-skin side of the top sheet, The aforementioned top sheet is The flat part that comes into contact with the skin, Multiple recesses are formed from the skin-facing surface of the flat portion toward the absorbent, Includes, Each of the aforementioned plurality of recesses is The bottom surface that comes into contact with the absorbent, A peripheral wall portion extending from the periphery of the bottom portion toward the flat portion, Includes, The thickness of the flat portion and the thickness of the bottom portion are 0.7 to 1.3 times that of the other. Absorbent material.

2. The flat portion extends along the longitudinal direction and comprises a plurality of longitudinal flat portions arranged at intervals in the width direction, A plurality of widthwise flat portions are arranged between adjacent longitudinal flat portions among the plurality of longitudinal flat portions, extending along the widthwise direction and spaced apart in the longitudinal direction, including, The absorbent article according to claim 1.

3. The shortest distance between adjacent recesses in the width direction in each of the plurality of recesses is greater than the shortest distance between adjacent recesses in the longitudinal direction in each of the plurality of recesses. The absorbent article according to claim 1 or 2.

4. Each of the aforementioned plurality of recesses, in a plan view, has a length in the longitudinal direction that is longer than the length in the width direction. The absorbent article according to claim 1 or 2.

5. The length in the width direction of each of the plurality of recesses is longer than the shortest distance between adjacent recesses in the width direction among the plurality of recesses. The absorbent article according to claim 1 or 2.

6. The thickness of the peripheral wall portion gradually decreases from the flat portion side toward the bottom portion side. The absorbent article according to claim 1 or 2.

7. The thickness of the portion of the peripheral wall adjacent to the flat portion is smaller than the thickness of the flat portion. The absorbent article according to claim 1 or 2.

8. The area ratio of the plurality of recesses to the top sheet is greater than the area ratio of the flat portion to the top sheet. The absorbent article according to claim 1 or 2.

9. The distance between the flat portion and the absorbent is longer than the distance between the bottom portion and the absorbent. The absorbent article according to claim 1 or 2.

10. The flat portion or the plurality of recesses has openings, The absorbent article according to claim 1 or 2.

11. The material further comprises material adjacent to the non-skin side of the top sheet, The color of the top sheet is different from the color of the material. The absorbent article according to claim 1 or 2.

12. The material placed on the non-skin side of the absorbent, A packaging bag for enclosing the absorbent article, Furthermore, A pattern design including the flat portion and the plurality of recesses of the top sheet is depicted on at least one of the non-skin surface of the material and the outer surface of the packaging bag. The absorbent article according to claim 1 or 2.

13. Nonwoven fabric for top sheet of absorbent articles, The aforementioned nonwoven fabric is A flat portion having a first surface and a second surface which is the back surface of the first surface, The flat portion comprises a plurality of recesses that are indented from the first surface toward the second surface, Includes, Each of the aforementioned plurality of recesses is The bottom part, A peripheral wall portion extending from the periphery of the bottom portion toward the flat portion, Includes, The thickness of the flat portion and the thickness of the bottom portion are 0.7 to 1.3 times that of the other. Nonwoven fabric for top sheet.

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