Absorbent articles

Abstract

To provide an absorbent article having excellent performance in preventing leakage of body fluids. [Solution] The absorbent article (1) has a high basis weight section (55) in which the basis weight of the absorbent core (5) is within a predetermined range, and a back-side low basis weight section (56R) located in the back section (R) and in which the basis weight of the absorbent core (5) is smaller than that of the high basis weight section (55). The back-side low basis weight section (56R) is located outward in the longitudinal direction (X) from the high basis weight section (55) and adjacent to the high basis weight section (55). A pair of longitudinally stretchable sections (70, 70) each have a portion that is in the same position in the longitudinal direction (X) as the back-side low basis weight section (56R). When the absorbent article (1) is worn, a back-side pleat (20) formed by deformation of a portion of the topsheet (3) located in the back-side low basis weight section (56R) extends in the transverse direction (Y) on the skin-facing surface of the topsheet (3)

Description

Technical Field

[0001] The present invention relates to absorbent articles such as disposable diapers.

Background Art

[0002] As an absorbent article, there is known one including an absorbent core that absorbs and holds body fluids, a surface sheet disposed on the skin-facing side of the absorbent core and contacting the wearer's skin during wearing, and a pair of leak-proof cuffs disposed corresponding to both side portions along the longitudinal direction (the direction corresponding to the front-rear direction of the wearer) of the absorbent core. Patent Documents 1 to 3 describe disposable diapers having such a configuration.

[0003] The diapers described in Patent Documents 1 and 2 have a fold extending in the lateral direction on the skin-facing surface of the surface sheet in the region sandwiched between one and the other of the pair of leak-proof cuffs. In the diapers described in Patent Documents 1 and 2, the basis weight of the absorbent core is uniform, and the fold is provided at a position overlapping the absorbent core of the uniform basis weight in plan view. The fold functions as a leak-proof wall for blocking relatively highly fluid body fluids such as soft feces, and according to the diapers described in Patent Documents 1 and 2, it is said that the fold can prevent the body fluids from leaking out from the longitudinal ends of the diaper. The fold in the diaper described in Patent Document 1 is formed by a folded portion (tack) of the surface sheet. In the diaper described in Patent Document 2, a plurality of surface sheets are arranged so as to overlap in the longitudinal direction, and a free edge (a non-fixed portion of the surface sheet with respect to other members in the surface sheet) of the surface sheet located at the overlapping portion of the plurality of surface sheets forms the fold.

[0004] The diaper described in Figures 19 and 20 of Patent Document 3 has a folded portion 19 formed by folding the vertical end of the absorbent body 2 (absorbent) back towards the surface sheet 3 side using a widthwise bending structure portion 7' ​​formed on the absorbent body 2 as a fold line 18, and is characterized by being compact despite having a folded portion 19 (see

[0067] ,

[0068] and

[0004] of Patent Document 3). The folded portion 19 functions as a leak-proof wall. According to the diaper described in Patent Document 3, because the leak-proof wall is absorbent, the area effective for absorbing bodily fluids is large, and the entire surface of the part that comes into contact with the wearer's skin contributes to urine absorption, thus eliminating material waste. The widthwise bending structure portion 7' ​​is a linear portion of the absorbent body 2 that is processed to allow the absorbent body 2 to be easily folded back, and is specifically a slit or a cut portion (see

[0027] and

[0028] of Patent Document 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-29597 [Patent Document 2] Japanese Patent Application Publication No. 10-314226 [Patent Document 3] Japanese Patent Publication No. 2008-23365 [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention relates to providing an absorbent article with excellent performance in preventing leakage of bodily fluids. [Means for solving the problem]

[0007] The present invention relates to an absorbent article comprising: an absorbent core having an abdominal portion positioned on the wearer's abdominal side when worn, a dorsal portion positioned on the wearer's back, and a crotch portion located between them, and having a longitudinal direction extending from the abdominal portion through the crotch portion to the dorsal portion and a transverse direction perpendicular to the longitudinal direction, and absorbing and retaining bodily fluids; a surface sheet positioned on the skin-facing side of the absorbent core and in contact with the wearer's skin when worn; and a pair of longitudinally stretchable portions positioned corresponding to both sides of the absorbent core along the longitudinal direction and extending in the longitudinal direction from the abdominal portion to the dorsal portion. In one embodiment of the absorbent article of the present invention, the article has a high basis weight portion in which the basis weight of the absorbent core is within a predetermined range, and a low basis weight portion on the back side located on the back side, wherein the basis weight of the absorbent core is smaller than that of the high basis weight portion, and it is preferable that the low basis weight portion on the back side is located further outward in the vertical direction than the high basis weight portion and is adjacent to the high basis weight portion. In one embodiment of the absorbent article of the present invention, it is preferable that each of the pair of longitudinally expandable portions has a portion that is in the same position in the longitudinal direction as the low-basis-weight portion on the back side. In one embodiment of the absorbent article of the present invention, it is preferable that when worn, a dorsal fold formed by the deformation of the portion located in the low-basis-weight portion on the back of the surface sheet extends in the lateral direction on the skin-facing surface of that portion. Other features, effects, and embodiments of the present invention are described below. [Effects of the Invention]

[0008] According to the present invention, an absorbent article with excellent performance in preventing leakage of bodily fluids is provided. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic perspective view of the back side of a pant-type disposable diaper, which is one embodiment of the absorbent article of the present invention. [Figure 2] Figure 2 is a plan view of the skin-facing side of the diaper shown in Figure 1, in its unfolded and stretched state. [Figure 3]Figure 3(a) is a schematic cross-sectional view showing a cross-section of the diaper shown in Figure 2 along line II (a cross-section along the transverse and thickness directions in the crotch area), and Figure 3(b) is a cross-sectional view of the same diaper when worn. [Figure 4] Figure 4 is a schematic cross-sectional view showing a cross-section of the diaper shown in Figure 2 along the line II-II (a cross-section along the vertical and thickness directions in the central part in the transverse direction). [Figure 5] Figure 5 is an enlarged view of a portion of the diagram corresponding to Figure 4 (dorsal fold and its vicinity) of another embodiment of the absorbent article of the present invention. [Modes for carrying out the invention]

[0010] The present invention will be described below with reference to the drawings, based on its preferred embodiments. Parts identical across multiple drawings are denoted by the same reference numerals. The drawings are generally schematic, and dimensions, dimensional ratios between parts, etc., may differ from those of the actual device.

[0011] Figures 1-4 show a disposable pant-type diaper 1, which is one embodiment of the absorbent article of the present invention. The diaper 1 has an abdominal portion F that is positioned on the wearer's abdominal side when worn, a dorsal portion R that is positioned on the wearer's back side, and a crotch portion M located between the abdominal portion F and the dorsal portion R. It also has a longitudinal direction X that extends from the abdominal portion F through the crotch portion M to the dorsal portion R, corresponding to the wearer's front-to-back direction, and a transverse direction Y that is perpendicular to the longitudinal direction X. The diaper 1 also includes an absorbent core 5 that absorbs and retains bodily fluids, a surface sheet 3 positioned on the skin-facing side of the absorbent core 5 and in contact with the wearer's skin when worn, and a pair of longitudinal stretchable portions 70, 70 positioned corresponding to both sides along the longitudinal direction X of the absorbent core 5 and extending in the longitudinal direction X from the abdominal portion F to the dorsal portion R.

[0012] In this embodiment, as shown in Figures 2 and 3, the diaper 1 is equipped with a leak-proof cuff 7 which is positioned on the skin-facing side of the absorbent core 5 and has an upright portion that stands up toward the wearer's skin when worn, and this upright portion is a vertically expandable portion 70.

[0013] The lower crotch part M extends in the longitudinal direction X across the longitudinal center line CL1 of the diaper 1. The longitudinal center line CL1 is a virtual straight line that bisects the diaper 1 in the longitudinal direction X in the unfolded and extended state as shown in FIG. 2 and extends in the transverse direction Y. The lower crotch part M includes an excretion part facing part (not shown) facing the excretion part such as the penis of the wearer, and typically includes the part where the length (width) in the transverse direction Y is the shortest in the diaper 1. In the present invention, the ventral part F, the lower crotch part M, and the dorsal part R can be the respective regions when the absorbent article in the unfolded and extended state is trisected in the longitudinal direction X.

[0014] As used herein, the “unfolded and extended state” means that the absorbent article is spread out flat to be in the unfolded state, and the elastic members of each part of the absorbent article in the unfolded state are extended until they reach the same dimensions as when the absorbent article is spread out flat in a state where the influence of the elastic members is completely excluded. In the case of an absorbent article having a side seal part, such as a pant-type disposable diaper, the absorbent article is separated at the side seal part and spread out flat to be in the unfolded state.

[0015] In the present embodiment, the diaper 1 includes an absorbent main body 2 containing an absorbent core 5 and an outer package 10 disposed on the non-skin-facing surface side of the absorbent main body 2. The absorbent main body 2 and the outer package 10 are joined by known joining means such as an adhesive.

[0016] As used herein, the “skin-facing surface” is the surface of the absorbent article or its constituent member (for example, the absorbent core) that faces the skin side of the wearer when the absorbent article is worn, that is, the side relatively close to the wearer's skin, and the “non-skin-facing surface” is the surface of the absorbent article or its constituent member that faces the side opposite to the skin side when the absorbent article is worn, that is, the side relatively far from the wearer's skin. Here, the “when worn” means a state where the normal proper wearing position, that is, the correct wearing position of the absorbent article is maintained.

[0017] The absorbent body 2 includes a liquid-permeable surface sheet 3 disposed at a position relatively close to the wearer's skin, a liquid-impermeable or liquid-hardly-permeable or water-repellent back sheet 4 disposed at a position relatively far from the wearer's skin, an absorbent core 5 interposed between the two sheets 3 and 4, and a core wrap sheet 6 having a portion that contacts the skin-facing surface or the non-skin-facing surface of the absorbent core 5. These members constituting the absorbent body 2 are integrated by known joining means such as an adhesive. The surface sheet 3 forms the outermost layer on the skin-facing surface side of the diaper 1 and can contact the wearer's skin during wearing of the diaper 1.

[0018] The core wrap sheet 6 includes a skin-side sheet 6A having a portion that contacts the skin-facing surface of the absorbent core 5 and a non-skin-side sheet 6B having a portion that contacts the non-skin-facing surface of the absorbent core 5. In the present embodiment, the core wrap sheet 6 is a single sheet, and the skin-side sheet 6A and the non-skin-side sheet 6B are each part of the single sheet. However, in the present invention, the form of the core wrap sheet is not limited to this, and the skin-side sheet 6A and the non-skin-side sheet 6B may be separate sheets from each other. That is, the core wrap sheet 6 may be configured to include a plurality of sheets 6A and 6B.

[0019] In the present embodiment, the surface sheet 3, the back sheet 4, and the core wrap sheet 6 each have an extension portion that extends outward from the peripheral edge of the absorbent core 5. That is, the surface sheet 3 covers the entire skin-facing surface of the absorbent core 5 and, as shown in FIG. 3, extends from the skin-facing surface side of the absorbent core 5 over the non-skin-facing surface side of the absorbent core 5 through both side edges (both ends in the transverse direction Y) along the longitudinal direction X of the absorbent core 5. Also, as shown in FIG. 4, it extends outward from the longitudinal ends 5X of the absorbent core 5 in the longitudinal direction X in the ventral portion F and the dorsal portion R. Further, the back sheet 4 covers the entire non-skin-facing surface of the absorbent core 5 and, as shown in FIG. 3, extends outward in the transverse direction Y from both side edges along the longitudinal direction X of the absorbent core 5. Also, as shown in FIG. 4, it extends outward from the longitudinal ends 5X of the absorbent core 5 in the longitudinal direction X in the ventral portion F and the dorsal portion R. Furthermore, as shown in Figure 4, the core wrap sheets 6 (6A, 6B) extend outward in the longitudinal direction X from the longitudinal end 5X of the absorbent core 5 in the ventral F and dorsal R portions. In this technical field, the portion where the absorbent core 5 and the core wrap sheets 6 overlap is sometimes referred to as the "absorbent material".

[0020] The surface sheet 3, back sheet 4, and core wrap sheet 6 can each be any material commonly used in this type of absorbent article, without any particular limitations. The surface sheet 3 and core wrap sheet 6 can be various permeable sheets, such as nonwoven fabrics, woven fabrics, and paper. The back sheet 4 can be a leak-proof sheet, specifically a sheet that is impermeable to liquids (not permeable to liquids at all) or has low permeability to liquids (not completely impermeable, but difficult to permeate), such as a moisture-permeable resin film or a laminate of the resin film and a nonwoven fabric.

[0021] The absorbent core 5 is mainly composed of a water-absorbing material. Examples of the water-absorbing material include hydrophilic fibers and water-absorbing polymers, and one of these can be used alone or in combination of two or more. Examples of the hydrophilic fibers include natural fibers such as wood pulp and hydrophilic synthetic fibers. As for the water-absorbing polymer, any polymer conventionally used in this type of absorbent can be used without particular limitation, and examples include polymers or copolymers of acrylic acid or alkali metal acrylate salts.

[0022] In this embodiment, as shown in Figure 2, the absorbent core 5 has a shape that is elongated in one direction in a plan view, specifically a rectangular shape, with its longitudinal direction coinciding with the vertical direction X of the diaper 1, extending from the ventral part F through the crotch area M to the dorsal part R. Since the crotch area M is the area where bodily fluids excreted from the wearer's excretory parts concentrate, it is preferable that the absorbent core 5, which has the ability to absorb and retain bodily fluids, be placed at least in the crotch area M. In this embodiment, the absorbent core 5 has a single-layer structure, but it may also have a laminated structure in which multiple layers are stacked in the thickness direction.

[0023] In this embodiment, the absorbent core 5 has a recess 51 extending in the vertical direction X, as shown in Figures 2 and 3. The recess 51 is located at least in the crotch area M and is formed symmetrically on one side and the other side with respect to the transverse center line CL2. The transverse center line CL2 is a virtual straight line that bisects the unfolded and extended diaper 1 in the transverse direction Y and extends in the vertical direction X. The recess 51 only needs to have an opening on at least one of the skin-facing surface and the non-skin-facing surface. It may be a through-type recess with openings on both the skin-facing surface and the non-skin-facing surface, or it may be a non-through-type recess with an opening on one of the skin-facing surface and a bottom on the other. The through-type recess 51 consists of a space where the material forming the absorbent core 5 (water-absorbing material) is substantially absent. In this embodiment, the recess 51 is of the through-type. The recess 51 functions as a channel for bodily fluids such as urine to flow, and can also function as a bending guide for the absorbent core 5. Therefore, because the absorbent core 5 has the recess 51, the liquid permeability or liquid diffusion in the absorbent core 5 is appropriately controlled, which is expected to improve the leak-proof properties of the diaper 1, and the desirable deformation of the absorbent core 5 during wear of the diaper 1 is promoted, which is expected to improve the wearing comfort of the diaper 1. One example of a method for forming the recess 51 is to avoid depositing the forming material (water-absorbing material) of the absorbent core 5 in the area where the recess 51 is to be formed during the manufacturing process of the absorbent core 5. Another example of a method for forming the recess 51 is to manufacture a precursor of the absorbent core 5 in which the amount of forming material deposited is uniform, and then remove the forming material from the area where the recess 51 is to be formed in the precursor.

[0024] As shown in Figures 2 and 3, the diaper 1 of this embodiment includes core stretching elastic members 52 that are stretchable in the longitudinal direction X and are positioned in the crotch area M to correspond to each of the side edges of the absorbent core 5 along the longitudinal direction X. One purpose of positioning the core stretching elastic members 52 is to cause both sides of the absorbent core 5 in the lateral direction Y (the side edges and their vicinity), more specifically, the portion of the absorbent core 5 located outward in the lateral direction Y from the recess 51, to stand up toward the wearer's skin when the diaper 1 is worn, as shown in Figure 3(b). This is expected to further improve the fit and leak-proof properties of the diaper 1. The core stretching elastic members 52 only need to be positioned in the crotch area M, and may extend from the crotch area M to the ventral side F and / or dorsal side R. Furthermore, the core stretching elastic members 52 only need to be positioned in correspondence with the side edges of the absorbent core 5 along the longitudinal direction X, that is, to be positioned on or near the side edges, and do not need to be in contact with the side edges. For example, in the illustrated configuration, the core expansion / contraction elastic member 52 is positioned between the absorbent core 5 and the core wrap sheet 6, but it may also be positioned between the core wrap sheet 6 and the surface sheet 3. The core expansion / contraction elastic member 52 is fixed in an extended state to other members such as the absorbent core 5 by known fixing means such as an adhesive.

[0025] The outer casing 10 includes an outer layer sheet 11 that forms the outer surface of the diaper 1 and an inner layer sheet 12 that forms the inner surface of the diaper 1. The two sheets 11 and 12 are joined together and integrated by adhesive. The outer casing 10 forms the outer shape of the diaper 1 in its unfolded and extended state as shown in Figure 2, and the periphery of the outer casing 10 forms the contour line of the diaper 1 in its unfolded and extended state. The outer casing 10 has a constriction in the crotch area M.

[0026] As shown in Figure 1, the diaper 1 has a pair of side seal portions S,S, which are formed by joining the two side edges of the ventral portion F and dorsal portion R of the outer body 10, along the longitudinal direction X, by known joining means such as heat sealing, ultrasonic sealing, or adhesive. The annular portion of the diaper 1 including the pair of side seal portions S,S is a waist portion that is positioned around the wearer's waist. The diaper 1 has a waist opening WH through which the wearer's waist passes, and below the waist portion (on the crotch side M), there is a pair of leg openings LH,LH through which the wearer's lower limbs pass.

[0027] The waist portion has multiple thread-like waist elastic members 13 that extend in the lateral direction Y between a pair of side seal portions S, S and are intermittently arranged in the vertical direction X. The waist elastic members 13 are fixed in an extended state in the lateral direction Y to at least one surface of the outer layer sheet 11 and the inner layer sheet 12, and have elastic stretchability in the lateral direction Y, contracting in their natural state. When the diaper 1 is worn, the waist portion adheres closely to the wearer's waist due to the contraction of the waist elastic members 13, and at that time, multiple folds (waist gathers) are formed on the surface of the waist portion (skin-facing surface and non-skin-facing surface) in a direction intersecting the extension direction (lateral direction Y) of the waist elastic members 13. In addition, thread-like leg elastic members 14 are arranged at the opening edges of each of the pair of leg openings LH, LH. The leg elastic member 14 is fixed in an extended state to the sheet (in this embodiment, the outer layer sheet 11 and the inner layer sheet 12) that constitute the area where it is positioned, and is contracted in its natural state. When the diaper 1 is worn, the contraction of the leg elastic member 14 forms multiple folds (leg gathers) around the entire circumference of the opening edge of the leg opening LH. In order to prevent unintended deformation of the absorbent core 5 due to the expansion and contraction of the waist elastic member 13 and the leg elastic member 14, the portions of both elastic members 13 and 14 that overlap with the absorbent core 5 in a plan view may be divided into multiple sections, thereby hindering their elasticity.

[0028] In this embodiment, as shown in Figures 1, 2, and 4, a disposal tape 15 is positioned on the non-skin-facing surface of the outer covering 10 (outer layer sheet 11) on the back side R. The disposal tape 15 is used to maintain the rolled-up state of the diaper 1 when it is rolled up for disposal, and includes a fixing portion to the outer covering 10 and a free portion that is positioned to be unfoldable starting from the fixing portion. Any type of disposal tape used in this type of absorbent article can be used without particular limitation as the disposal tape 15.

[0029] As shown in Figures 2 and 3, the leak-proof cuffs 7 are arranged in pairs on the skin-facing side of the absorbent core 5, corresponding to both sides of the absorbent core 5 in the transverse direction Y. The pair of leak-proof cuffs 7, 7 are formed symmetrically on one side and the other side with respect to the transverse center line CL2. The leak-proof cuff 7 comprises a cuff sheet 8 extending longitudinally X from the ventral side F through the crotch area M to the dorsal side R, and a cuff elastic member 9 fixed to the cuff sheet 8 and expandable and contractible longitudinally X at least in the crotch area M.

[0030] The cuff sheet 8, together with the surface sheet 3, forms the outermost layer on the skin-facing side of the diaper 1 and can come into contact with the wearer's skin while the diaper 1 is being worn. As shown in Figure 2, the cuff sheet 8 has a pair of fixing portions 80 at both ends in the vertical direction X that secure it to other members (in this embodiment, the surface sheet 3). One of the pair of fixing portions 80, 80 is located on the ventral side F, and the other is located on the dorsal side R. Furthermore, as shown in Figure 3, the portion of the cuff sheet 8 sandwiched between the pair of fixing portions 80, 80 has a fixing portion 81 at one end in the horizontal direction Y that secures it to other members (in this embodiment, the surface sheet 3 and the back sheet 4), and the other end is a free edge portion 82. The aforementioned end of the cuff sheet 8 is located on the non-skin-facing side of the absorbent core 5. The means of securing the cuff sheet 8 to the other members at the fixing portions 80, 81 are not particularly limited and may be, for example, adhesive or fusion.

[0031] In this embodiment, the elastic cuff member 9 includes a first elastic cuff member 9A positioned on the free edge 82 of the cuff sheet 8, and a second elastic cuff member 9B positioned between the fixing portion 81 (the fixing portion 81 located at the outermost edge in the lateral direction Y) and the free edge 82. More specifically, the cuff sheet 8 has a two-layer structure formed by folding the cuff sheet 8 in the lateral direction Y, and a thread-like elastic cuff member 9 is fixed in an extended state in the vertical direction X between the opposing cuff sheets 8, 8 that constitute the two-layer structure.

[0032] As described above, the leak-proof cuff 7 has a vertically expandable portion 70 as the upright portion, and the portion of the leak-proof cuff 7 in which the elastic cuff member 9 is fixed in an extended state (the portion where the elastic cuff member 9 is located, shown by the dotted line in Figure 2) is the vertically expandable portion 70. The vertically expandable portion 70 is positioned corresponding to the side portion of the absorbent core 5 along the vertical direction X, extends in the vertical direction X from the ventral side F to the dorsal side R, and is expandable in the vertical direction X. When the diaper 1 is worn, as shown in Figure 3(b), the vertically expandable portion 70 stands up toward the wearer's skin, thereby effectively preventing the inconvenience of excreted bodily fluids such as urine flowing outward in the horizontal direction Y from the diaper 1 (so-called lateral leakage). Furthermore, although not shown in the diagram, when the vertically expandable portion 70 is in an upright position, the elastic member 9 for the cuff contracts, causing the entire diaper 1 to curve and deform so that the central part of the absorbent body 2 in the vertical direction X becomes convex towards the non-skin-facing side (back sheet 4 side), making it easier for the diaper 1 to fit the wearer's body shape.

[0033] As the cuff sheet 8, any material used as a leak-proof cuff material in this type of absorbent article can be used without particular limitations. For example, a single-layer or multi-layer water-repellent nonwoven fabric, a laminate of resin film and nonwoven fabric, etc., can be used. The number of elastic cuff members 9 in each of the pair of leak-proof cuffs 7, 7 is not particularly limited and may be one or more. One of the main purposes of the elastic cuff members 9 is to make the leak-proof cuff 7 (cuff sheet 8) stand upright towards the wearer's skin when the diaper 1 is worn. To achieve this purpose, it is sufficient that at least one elastic cuff member 9 is placed on the free edge 82 of the cuff sheet 8. Therefore, the second elastic cuff member 9B is not necessary.

[0034] As shown in Figure 4, diaper 1 has a high basis weight section 55 in which the basis weight of the absorbent core 5 is within a predetermined range, and a low basis weight section 56R on the back side R, in which the basis weight of the absorbent core 5 is smaller than that of the high basis weight section 55. The low basis weight section 56R on the back side is located further outward in the vertical direction X than the high basis weight section 55 and is adjacent to the high basis weight section 55. In this embodiment, the high-basis-weight portion 55 is located on the back side R, but in the present invention, the position of the high-basis-weight portion 55 is not limited to the back side R, but may be located in the crotch area M.

[0035] In this embodiment, the basis weight of the absorbent core 5 in the dorsal low basis weight portion 56R is zero. Specifically, in this embodiment, except for the recess 51, the basis weight of the absorbent core 5 is uniform, and as shown in Figure 4, the absorbent core 5 with uniform basis weight extends in the longitudinal direction X along the entire length of the crotch area M, and further extends to the ventral portion F and the dorsal portion R respectively. In the dorsal portion R, there is a high basis weight portion 55 (the area where the absorbent core 5 is present) and a dorsal low basis weight portion 56R (the area where the absorbent core 5 is not present), and the longitudinal end 5X on the dorsal portion R side of the absorbent core 5 is the boundary between the two. In the dorsal low basis weight portion 56R, instead of the material that forms the absorbent core 5 (water-absorbing material), there is a surface sheet 3, a back sheet 4, a core wrap sheet 6 (skin-side sheet 6A, non-skin-side sheet 6B), and an outer covering 10 (outer layer sheet 11, inner layer sheet 12).

[0036] If the basis weight of the absorbent core 5 in the low basis weight section 56R on the back side is not zero, the ratio of the basis weight of the absorbent core 5 in the low basis weight section 56R on the back side to the basis weight of the absorbent core 5 in the high basis weight section 55 is, from the viewpoint of appropriately adjusting the difference in rigidity between the low basis weight section 56 and the high basis weight section 55 on the back side and making the formation of the back side folds 20, described later, more certain to be certain, assuming that the former < the latter, preferably the former / latter is 0.2 or more, more preferably 0.3 or more, and preferably 0.8 or less, more preferably 0.7 or less. The basis weight of the absorbent core 5 in the high basis weight section 55 is preferably 250 g / m², from the viewpoint of balancing the liquid absorption capacity of the absorbent core 5 with the wearing comfort of the diaper 1. 2 More than 700g / m 2 The following applies:

[0037] In this embodiment, the diaper 1 has low-basis-weight sections in both the dorsal and ventral portions F, such as the dorsal low-basis-weight section 56R, where the basis weight of the absorbent core 5 is relatively small. That is, as shown in Figure 4, the diaper 1 in this embodiment has a high-basis-weight section 55 and a ventral low-basis-weight section 56F in the ventral portion F, where the basis weight of the absorbent core 5 is smaller than that of the high-basis-weight section 55. The ventral low-basis-weight section 56F is located further outward in the vertical direction X than the high-basis-weight section 55 and is adjacent to the high-basis-weight section 55. In this embodiment, the basis weight of the absorbent core 5 in the ventral low-basis-weight section 56F is zero. That is, in this embodiment, the ventral portion F has a high-basis-weight section 55 and a ventral low-basis-weight section 56F (a region where the absorbent core 5 does not exist), and the vertical end 5X on the ventral portion F side of the absorbent core 5 is the boundary between the two.

[0038] As shown in Figure 2, each of the pair of vertically expandable sections 70, 70 has a portion that is in the same position in the vertical direction X as the back low-basis-weight section 56R. In other words, when the pair of vertically expandable sections 70, 70 and the back low-basis-weight section 56R are projected in the horizontal direction Y, at least a portion of the projected image of the pair of vertically expandable sections 70, 70 and the projected image of the back low-basis-weight section 56R overlap.

[0039] As shown in Figures 2 and 4, diaper 1 is characterized in that, when worn, a dorsal fold 20, formed by the deformation of the portion located in the dorsal low-basis-weight portion 56R of the surface sheet 3, extends in the lateral direction Y. As mentioned above, the dorsal low-basis-weight portion 56R is adjacent to the high-basis-weight portion 55 in the vertical direction X. Therefore, in diaper 1 having such characteristics, there is a difference in basis weight between the region where the dorsal fold 20 is formed (the region enclosed by the smallest area of ​​a hypothetical rectangle that encloses the entire dorsal fold 20 in a plan view of the skin-facing side of diaper 1 as shown in Figure 2) and the region located inward in the vertical direction X from the formed region (high-basis-weight portion 55). The dorsal fold 20 is typically formed when a portion of the low-basis-weight portion 56R on the dorsal side of the surface sheet 3 is folded in the longitudinal direction X with its non-skin-facing side facing inward, in other words, it is folded along an imaginary line extending in the transverse direction Y. The reason why the dorsal folds 20 are formed in the dorsal low-basis-weight portion 56R is that a pair of longitudinally stretchable portions 70, 70, which are stretchable in the longitudinal direction X, are positioned at the same location in the longitudinal direction X as the dorsal low-basis-weight portion 56R. As mentioned above, the pair of longitudinally stretchable portions 70, 70 are positioned corresponding to both sides of the absorbent core 5 along the longitudinal direction X, so the dorsal low-basis-weight portion 56R has a portion sandwiched between one and the other of the pair of longitudinally stretchable portions 70, 70. Therefore, when the pair of longitudinally stretchable portions 70, 70 contract in the longitudinal direction X when the diaper 1 is worn, the contraction force acts on the region sandwiched between the pair of longitudinally stretchable portions 70, 70, and in that region, the basis weight of the absorbent core 5 is relatively small and therefore the rigidity is relatively low, so the dorsal folds 20 are formed on the surface sheet 3 of the dorsal low-basis-weight portion 56R. The dorsal fold 20 functions as a leak-proof barrier that blocks bodily fluids such as loose stool that flow along the skin-facing surface of the surface sheet 3. Therefore, with diaper 1, the inconvenience of bodily fluids leaking out from the longitudinal X end on the dorsal side R is prevented. In particular, since fecal leakage tends to occur more frequently on the dorsal side R than on the ventral side F, the dorsal fold 20 is effective in preventing fecal leakage.

[0040] Leak-proof walls for preventing leakage from the longitudinal ends of absorbent articles, such as the dorsal fold 20, are also described in Patent Documents 1 to 3. However, the leak-proof walls described in these documents are formed by folding the surface sheet to form a tuck, arranging multiple surface sheets to overlap in the longitudinal direction, or folding the absorbent material at a linear bending structure such as a slit. In all cases, these are formed through a bending process of the constituent members of the absorbent article, regardless of the presence of a longitudinally expandable portion such as the longitudinally expandable portion 70. In contrast, the dorsal fold 20 is formed in the dorsal low-basis-weight portion 56R when the longitudinally expandable portion 70 contracts in the longitudinal direction X, and is not formed through the aforementioned bending process. Furthermore, the longitudinally expandable portion 70 was originally adopted as the upright portion of the leak-proof cuff 7, as described above, and was not adopted solely for the purpose of forming the dorsal fold 20. In other words, the dorsal fold 20 can be formed using only common components in absorbent articles such as leak-proof cuffs, without requiring a special process for forming the dorsal fold 20, such as the aforementioned folding process. Therefore, the absorbent article of the present invention, represented by the diaper 1, has a relatively simple structure with a basic configuration similar to conventionally known absorbent articles, but it can be said to have superior leakage prevention performance for bodily fluids compared to conventionally known absorbent articles.

[0041] Furthermore, when worn, a ventral fold (not shown) formed by the deformation of the ventral low-basis-weight portion 56F of the surface sheet 3 may extend in the transverse direction Y on the skin-facing surface of that portion. However, typically, the dorsal fold 20 is taller than the ventral fold. This is because, as shown in Figure 2, the ventral low-basis-weight portion 56F is located further outward in the longitudinal direction X than each of the pair of longitudinal stretch portions 70, 70, and does not have a portion in the same position as them in the longitudinal direction X. Therefore, it is less affected by the contraction force when they contract in the longitudinal direction X. In other words, the dorsal fold 20 can typically be distinguished from ordinary folds (wrinkles) formed on the surface sheet in this type of absorbent article by being taller than such folds (wrinkles).

[0042] Typically, the dorsal fold 20 is present only in the low-basis-weight section 56R on the dorsal side, as shown in Figure 2, and not in the high-basis-weight section 55. That is, typically, in a plan view of the skin-facing side (surface sheet 3 side) of the diaper 1 as shown in Figure 2, the entire dorsal fold 20 overlaps with the low-basis-weight section 56R on the dorsal side. However, depending on the stretching characteristics of the longitudinal stretchable section 70, the type of surface sheet 3, etc., the dorsal fold 20 may exist across both the low-basis-weight section 56R and the high-basis-weight section 55 on the dorsal side.

[0043] The height 20H of the dorsal fold 20 (see Figure 4) is preferably higher from the viewpoint of improving the leak-proof function, and specifically, preferably 1 mm or more, more preferably 3 mm or more. The "height of the dorsal fold 20" referred to here refers to the maximum height of the dorsal fold 20, regardless of whether the diaper 1 is in its natural state (a state in which no external force is acting on the diaper 1) or in an extended state. There is no particular upper limit to the height 20H of the dorsal fold 20, but as mentioned above, the dorsal fold 20 is mainly formed by arranging a pair of vertically expanding and contracting parts 70, 70 at the same position in the vertical direction X with the dorsal low basis weight part 56R, and from the viewpoint of stably forming a dorsal fold 20 with sufficient leak-proof function with such a relatively simple structure of absorbent article, it is preferably 12 mm or less, more preferably 10 mm or less. The height 20H of the dorsal fold 20 can be adjusted, for example, by appropriately adjusting the stretchability of the longitudinal stretchable portion 70, the type of surface sheet 3, etc. The stretchability of the longitudinal stretchable portion 70 can be adjusted, for example, by adjusting the elongation rate, thickness, etc. of the elastic cuff member 9 that constitutes the longitudinal stretchable portion 70.

[0044] The dorsal fold 20 is typically curved convexly outward in the longitudinal direction X in a plan view, as shown in Figure 2. The apex of the convex dorsal fold 20 in a plan view is located in the center of the dorsal low-basis-weight portion 56R in the transverse direction Y, and both ends of the dorsal fold 20 in the transverse direction Y are located at or near the boundary between the high-basis-weight portion 55 and the dorsal low-basis-weight portion 56R (in this embodiment, the longitudinal end 5X on the dorsal R side of the absorbent core 5) on the longitudinal X side of the apex. The dorsal fold 20 has such a curved shape in a plan view, which can further improve the fluid damming function of the dorsal fold 20. In addition to the form shown in Figure 2, which consists of a single dorsal fold 20 continuous in the transverse direction Y, there may also be a form, although not shown, in which multiple small folds are substantially connected in the transverse direction Y to form a single dorsal fold 20 as a whole. Furthermore, in the form shown in Figure 2, only a part of the dorsal fold 20 (both ends in the transverse direction Y) is in the same position as the pair of longitudinal expansion / contraction parts 70, 70 in the longitudinal direction X, but there may also be a case where the entire dorsal fold 20 is in the same position as the pair of longitudinal expansion / contraction parts 70, 70 in the longitudinal direction X. The planar shape of the dorsal fold 20 can be adjusted, for example, by appropriately adjusting the stretching characteristics of the longitudinal stretchable portion 70, the type of surface sheet 3, etc.

[0045] The length 20Ly (see Figure 2) of the dorsal fold 20 along the transverse direction Y is preferably 40% or more, more preferably 50% or more, and preferably 100% or less, and more preferably 95% or less, of the maximum length of the absorbent core 5 in the transverse direction Y. The length 20Ly of the dorsal fold 20 is preferably 50 mm or more, more preferably 60 mm or more, and preferably 135 mm or less, more preferably 130 mm or less. The length 20Ly of the dorsal fold 20 can be adjusted, for example, by appropriately adjusting the stretchability of the longitudinal stretchable portion 70, the type of surface sheet 3, etc.

[0046] As shown in Figure 4, the dorsal fold 20 is oriented so that its tip 20T faces the crotch area M; in other words, it is preferable that the dorsal fold 20 is inclined toward the crotch area M. Since bodily fluids such as loose stools usually flow from the crotch area M toward the dorsal fold 20, this orientation of the dorsal fold 20 is expected to further improve its leak-proof function. This orientation of the dorsal fold 20 can be adjusted, for example, by appropriately adjusting the stretchability characteristics of the longitudinal stretchable portion 70, the type of surface sheet 3, etc.

[0047] In this embodiment, as described above, the diaper 1 is equipped with core wrap sheets 6 (6A, 6B) that have portions that come into contact with the skin-facing or non-skin-facing surface of the absorbent core 5, and the dorsal fold 20 overlaps with the core wrap sheet 6 in a plan view. More specifically, in this embodiment, as shown in Figure 4, in the dorsal low basis weight portion 56R, there is a non-core wrap sheet 6 area where only the outer casing 10 is placed, located outward in the vertical direction X from the core wrap sheet 6 placement area. However, the dorsal fold 20 overlaps with the core wrap sheet 6 placement area in a plan view, but does not overlap with the non-core wrap sheet 6 area in a plan view. Thus, by having the dorsal fold 20 in a position that overlaps with the core wrap sheet 6 in a plan view, a further improvement in the leak-proof effect of the dorsal fold 20 can be expected.

[0048] In the configuration shown in Figure 4, the dorsal fold 20 is composed only of the surface sheet 3. However, depending on the expansion and contraction characteristics of the longitudinal expansion portion 70, the types of other materials present in the low-basis-weight portion 56R on the dorsal side other than the surface sheet 3, etc., other materials may be present inside the dorsal fold 20.

[0049] For example, in the configuration shown in Figure 5, the core wrap sheet 6 is located inside the dorsal fold 20. More specifically, in the configuration shown in Figure 5, the core wrap sheet 6 includes a skin-side sheet 6A and a non-skin-side sheet 6B, with both sheets 6A and 6B folded inside the dorsal fold 20, that is, between one and the other of the folded two-layer surface sheet 3. In the present invention, a modification of the configuration shown in Figure 5 includes a configuration in which only the skin-side sheet 6A is located inside the dorsal fold 20, and the non-skin-side sheet 6B is absent. Since the core wrap sheet 6 (6A, 6B) is typically made from a material that can absorb bodily fluids (nonwoven fabric, woven fabric, paper, etc.), the presence of the core wrap sheet 6 inside the dorsal fold 20 improves the bodily fluid absorption capacity of the dorsal fold 20, and further improvement in leak-proof function can be expected.

[0050] As described above in this embodiment, the basis weight of the absorbent core 5 in the low basis weight section 56R on the back side is zero, and the absorbent core 5 is not arranged in the low basis weight section 56R on the back side. However, in the present invention, there are cases in which the absorbent core 5 is arranged in the low basis weight section 56R on the back side. In that case, there may be a form (hereinafter also referred to as "Form A") in which the absorbent core 5 (specifically, a portion of the absorbent core 5 with a smaller basis weight than the portion arranged in the high basis weight section 55) exists inside the back side pleat 20. An example of Form A is a form in which the skin-side sheet 6A, the absorbent core 5, and the non-skin-side sheet 6B are folded inside the back side pleat 20 in order from closest to the surface sheet 3 that constitutes the back side pleat 20. According to the above-described embodiment A, since the absorbent core 5 is present inside the dorsal fold 20, the fluid absorption capacity of the dorsal fold 20 is improved, and further improvement in the leak-proof function can be expected.

[0051] As described above in this embodiment, the backing sheet 4 is arranged on the non-skin-facing side of the absorbent core 5. However, in the present invention, there is a form in which the backing sheet 4 is located inside the dorsal fold 20 (hereinafter also referred to as "form B"). An example of form B is a form in which the core wrap sheet 6 (6A and / or 6B) and the backing sheet 4 are folded inside the dorsal fold 20 in order of proximity to the surface sheet 3 that constitutes the dorsal fold 20. Another example of form B is a form in which, in an example of form B, the absorbent core 5 is folded between the skin-facing sheet 6A and the non-skin-facing sheet 6B that constitute the core wrap sheet 6. Since the back sheet 4 is typically formed from a leak-proof sheet, according to embodiment B, a further improvement in the leak-proof function of the dorsal fold 20 can be expected.

[0052] As described above in this embodiment, the diaper 1 comprises an absorbent body 2 and an outer casing 10. However, in the present invention, there is a form in which the outer casing 10 (outer layer sheet 11 and / or inner layer sheet 12) is located inside the dorsal fold 20 (hereinafter also referred to as "form C"). An example of form C is a form in which the core wrap sheet 6 (6A and / or 6B), the back sheet 4, and the outer casing 10 are folded inside the dorsal fold 20 in order from closest to the surface sheet 3 that constitutes the dorsal fold 20. Another example of form C is a form in which, in an example of form C, the absorbent core 5 is folded between the skin-side sheet 6A and the non-skin-side sheet 6B. Because the outer casing 10 is located inside the dorsal fold 20, the size (height, etc.) of the dorsal fold 20 becomes larger compared to the case where the outer casing 10 is not present. Therefore, according to embodiment C, a further improvement in the leak-proof function of the dorsal fold 20 can be expected.

[0053] As a modification of the above-mentioned form C, in which the outer casing 10 is located inside the dorsal fold 20, a form is provided in which a disposal tape used when disposing of absorbent articles is fixed to the non-skin-facing surface of the portion of the outer casing 10 that overlaps with the dorsal fold 20 in a plan view. For example, in diaper 1, as shown in Figure 2, the dorsal fold 20 and the disposal tape 15 overlap in a plan view, and a form in which the outer casing 10 is located inside this dorsal fold 20 (not shown) corresponds to a modification of the above-mentioned form C. In the modification of the above-mentioned form C, one and the other of the two-layer structure of the outer casing 10 folded inside the dorsal fold 20 are fixed by the disposal tape 15, so the dorsal fold 20 is always present regardless of whether the absorbent article is in its natural state, worn, or in the unfolded and stretched state as shown in Figure 2, and therefore the leakage prevention effect of the dorsal fold 20 is more reliably achieved.

[0054] The present invention is applicable to absorbent articles in general. The term "absorbent article" as used herein broadly includes articles used to absorb bodily fluids (urine, loose stools, menstrual blood, sweat, etc.) discharged from the human body, and in addition to the pant-type disposable diaper described above, it also includes, for example, unfoldable disposable diapers, sanitary shorts, incontinence pads, etc. The unfoldable disposable diaper is a disposable diaper in which the abdominal and dorsal parts are not connected when unused, and the waist portion that is positioned around the wearer's waist does not form a ring. Typically, a fastening tape is provided on the dorsal part, and when in use, the fastening tape is fastened to the non-skin-facing side of the abdominal part and attached to the body.

[0055] Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above embodiments and can be modified as appropriate without hindering the predetermined effects of the present invention. For example, in the above embodiment, the upright portion of the leak-proof cuff 7 was the longitudinally expandable portion according to the present invention. However, the longitudinally expandable portion is not limited to a part of the leak-proof cuff 7, as long as it is arranged in correspondence with the side portion of the absorbent core 5 along the longitudinal direction X, extends in the longitudinal direction X from the ventral portion F to the dorsal portion R, and is expandable in the longitudinal direction X. For example, the core expansion elastic member 52 may be the longitudinally expandable portion according to the present invention, provided that the core expansion elastic member 52 has a portion that is in the same position in the longitudinal direction X as the dorsal low-basis-weight portion 56R. Furthermore, in the above embodiment, the outer casing 10 was a type of outer casing that extended continuously from the ventral part F through the crotch area M to the dorsal part R, but it may also be a divided type of outer casing that is divided into a member located on the ventral side and a member located on the dorsal side.

[0056] With regard to the embodiments of the present invention described above, the following additional information is disclosed. <1> It has an abdominal portion that is positioned on the wearer's abdominal side when worn, a dorsal portion that is positioned on the wearer's back, and a crotch portion located between them, and has a longitudinal direction extending from the abdominal portion through the crotch portion to the dorsal portion and a transverse direction perpendicular to the longitudinal direction. An absorbent article comprising: an absorbent core that absorbs and retains bodily fluids; a surface sheet disposed on the skin-facing side of the absorbent core and in contact with the wearer's skin when worn; and a pair of longitudinally stretchable portions disposed corresponding to both sides of the absorbent core along the longitudinal direction and extending in the longitudinal direction from the ventral side to the dorsal side, The absorbent core has a high basis weight portion where the basis weight is within a predetermined range, and a low basis weight portion on the back side where the basis weight of the absorbent core is smaller than that of the high basis weight portion, and the low basis weight portion on the back side is located further outward in the vertical direction than the high basis weight portion and is adjacent to the high basis weight portion. Each of the pair of vertically expanding portions has a portion that is in the same position in the vertical direction as the low basis weight portion on the back side, An absorbent article in which, when worn, a dorsal fold formed by deformation of the portion located in the low-basis-weight portion on the dorsal side of the surface sheet extends in the lateral direction on the skin-facing surface of the portion located in the low-basis-weight portion on the dorsal side. <2> The leak-proof cuff is provided, which is positioned on the skin-facing side of the absorbent core and has an upright portion that stands up toward the wearer's skin when worn, wherein the upright portion is the vertically stretchable portion, <1> Absorbent articles as described above. <3> The ventral portion has a high basis weight portion and a ventral low basis weight portion where the basis weight of the absorbent core is smaller than that of the high basis weight portion, and the ventral low basis weight portion is located further outward in the longitudinal direction than the high basis weight portion and is adjacent to the high basis weight portion. When worn, the portion of the surface sheet located in the ventral low-basis-weight area has a ventral fold that extends in the lateral direction, formed by the deformation of that portion. The dorsal fold is taller than the ventral fold, <1> or <2> Absorbent articles as described above.

[0057] <4> The dorsal fold is present only in the dorsal low basis weight portion, <1> ~ <3> The absorbent article described in any one of the following (1). <5> The height of the dorsal fold is 1 mm or more, <1> ~ <4> The absorbent article described in any one of the following (1). <6> The dorsal fold is curved convexly outward in the longitudinal direction when viewed in plan, <1> ~ <5> The absorbent article described in any one of the following (1). <7> The dorsal fold is oriented such that the tip of the dorsal fold faces the crotch area. <1> ~ <6> The absorbent article described in any one of the following (1). <8> The core wrap sheet comprises a portion that contacts the skin-facing or non-skin-facing surface of the absorbent core, and the dorsal fold overlaps with the core wrap sheet in a plan view. <1> ~ <7> The absorbent article described in any one of the following (1). <9> The core wrap sheet is located inside the dorsal fold, <8> Absorbent articles as described above.

[0058] <10> Within the dorsal fold, there exists a portion located in the low-basis-weight portion on the dorsal side of the absorbent core, <1> ~ <9> The absorbent article described in any one of the following (1). <11> The absorbent core is provided with a backing sheet positioned on the non-skin-facing side, The back sheet is located inside the dorsal fold, <1> ~ <10> The absorbent article described in any one of the following (1). <12> The absorbent body comprises the surface sheet and the absorbent core, and an outer casing disposed on the non-skin-facing side of the absorbent body. The outer casing is located inside the dorsal fold, and a disposal tape used when disposing of the absorbent article is fixed to the non-skin-facing surface of the portion of the outer casing that overlaps with the dorsal fold in a plan view, <1> ~ <11> The absorbent article described in any one of the following (1). <13> The basis weight of the absorbent core in the low basis weight portion on the back side is zero, <1> ~ <12> The absorbent article described in any one of the following (1). [Explanation of Symbols]

[0059] 1. Pant-type disposable diapers (absorbent material) 2 Absorbent body 3. Surface sheet 4. Backing sheet 5 Absorbent core 51 Recess 6 Core Wrap Sheets 6A Skin-side sheet 6B Non-skin side sheet 7 Leak proof cuff 70 Vertically expandable section 10 Exterior 15 Disposal Tape 20 Dorsal folds 55 High basis weight part 56R Dorsal low basis weight part 56F Ventral low basis weight part X vertical direction Y (horizontal direction) F ventral part M Inseam R dorsal part

Claims

1. It has an abdominal portion that is positioned on the wearer's abdominal side when worn, a dorsal portion that is positioned on the wearer's back, and a crotch portion located between them, and has a longitudinal direction extending from the abdominal portion through the crotch portion to the dorsal portion and a transverse direction perpendicular to the longitudinal direction. An absorbent article comprising: an absorbent core that absorbs and retains bodily fluids; a surface sheet disposed on the skin-facing side of the absorbent core and in contact with the wearer's skin when worn; a pair of longitudinally stretchable portions disposed corresponding to both sides of the absorbent core along the longitudinal direction and extending longitudinally from the ventral side to the dorsal side; and a waist elastic member that extends transversely in a waist portion disposed around the wearer's waist, The absorbent core has a high basis weight portion where the basis weight is within a predetermined range, and a low basis weight portion on the back side where the basis weight of the absorbent core is smaller than that of the high basis weight portion, and the low basis weight portion on the back side is located further outward in the vertical direction than the high basis weight portion and is adjacent to the high basis weight portion. The basis weight of the absorbent core in the low basis weight portion on the back side is zero. Each of the pair of vertically expanding portions has a portion that is in the same position in the vertical direction as the low basis weight portion on the back side, When worn, a dorsal fold, formed by the deformation of the portion of the surface sheet located in the low-basis-weight portion on the back, extends in the lateral direction on the skin-facing surface of that portion. The dorsal fold is formed when a portion of the surface sheet located in the low-basis-weight area on the dorsal side is folded in the longitudinal direction with its non-skin-facing surface facing inward. An absorbent article in which the elastic member around the torso is not present inside the dorsal fold.

2. The absorbent article according to claim 1, further comprising a leak-proof cuff having an upright portion disposed on the skin-facing side of the absorbent core and which stands up toward the wearer's skin when worn, wherein the upright portion is the longitudinally stretchable portion.

3. The ventral portion has a high basis weight portion and a ventral low basis weight portion where the basis weight of the absorbent core is smaller than that of the high basis weight portion, and the ventral low basis weight portion is located further outward in the longitudinal direction than the high basis weight portion and is adjacent to the high basis weight portion. When worn, the portion of the surface sheet located in the ventral low-basis-weight area has a ventral fold that extends in the lateral direction, formed by the deformation of that portion. The absorbent article according to claim 1 or 2, wherein the dorsal fold is taller than the ventral fold.

4. The absorbent article according to claim 1 or 2, wherein the height of the dorsal fold is 1 mm or more.

5. The absorbent article according to claim 1 or 2, wherein the dorsal fold is oriented such that the tip of the dorsal fold faces the crotch area.

6. The absorbent article according to claim 1 or 2, comprising a core wrap sheet having a portion that contacts the skin-facing or non-skin-facing surface of the absorbent core, wherein the dorsal fold overlaps with the core wrap sheet in a plan view.

7. The absorbent article according to claim 6, wherein the core wrap sheet is located inside the dorsal fold.

8. The absorbent article according to claim 1 or 2, wherein a portion located in the low-basis-weight portion on the dorsal side of the absorbent core exists inside the dorsal side fold.

9. The absorbent core is provided with a backing sheet positioned on the non-skin-facing side, The absorbent article according to claim 1 or 2, wherein the backing sheet is located inside the dorsal fold.

10. The absorbent body comprises the surface sheet and the absorbent core, and an outer casing disposed on the non-skin-facing side of the absorbent body. The absorbent article according to claim 1 or 2, wherein the outer casing is located inside the dorsal fold, and a disposal tape used when disposing of the absorbent article is fixed to the non-skin-facing surface of the portion of the outer casing that overlaps with the dorsal fold in a plan view.

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