JP5806867B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as disposable diapers, sanitary napkins, and incontinence pants.

  In absorbent articles such as disposable diapers, the material and structure of each member have been improved to improve the functional wearing feeling. For example, surface sheets and absorbent bodies as members have also been developed with the aim of such improvements, and recently, various types having improved functionality in accordance with the use situation and the type of article have been proposed.

  Patent Document 1 discloses an absorbent article in which the absorbent body itself is in close contact with the surface sheet to form an uneven shape. Thereby, the internal transferability of the liquid is enhanced, and a soft touch can be realized. Patent Document 2 discloses a sanitary napkin that has a large number of recesses extending from the skin contact surface side to the inside in the excretion facing region of the sanitary napkin. In this napkin, the surface area on the skin contact surface side of the absorber is increased, and the liquid is captured by the concave portion and drawn into the inside. Therefore, the diffusion of the liquid on the skin surface side is suppressed, and the spot absorbability is excellent. This is due to the shape of the absorber itself.

JP 2009-1119022 A JP 2008-18048 A

  The present invention further enhances the absorption performance of the conventional absorbent article, and even when there is repeated excretion fluid or a large amount of excretion fluid, while the diffusion of the liquid in the surface sheet is suppressed, the liquid is quickly drawn in and the inside of the absorber It is an object of the present invention to provide an absorbent article that can be diffused and efficiently absorbed and held.

  The present invention is an absorbent article having a liquid-permeable surface sheet disposed on the skin contact surface side, a back sheet disposed on the non-skin contact surface side, and an absorbent body interposed between the both sheets. The surface sheet is made of a nonwoven fabric, and the absorbent body has an absorbent core and a covering sheet that covers the absorbent core, and the surface sheet is recessed toward the skin contact surface side on the non-skin contact surface side. A plurality of back surface recesses are arranged adjacent to each other, the covering sheet enters the back surface recesses, and the above problem is caused by the absorbent article in which a space portion exists between the entering coating sheet and the absorbent core. Is a solution.

  In the absorbent article of the present invention, by allowing a space portion to exist between the back surface concave portion, the covering sheet that has entered the covering sheet, and the covering sheet and the absorbent core, liquid diffusion on the surface sheet side is suppressed to the inside of the liquid. The drawing force can be increased, and the drawn liquid can be diffused in the absorbent core to quickly fix the liquid inside. Therefore, the absorbent article of the present invention further enhances the absorption performance of the conventional absorbent article, and even if there is a repeated excretion liquid or a large amount of excretion liquid, the liquid is suppressed while suppressing the diffusion of the liquid on the surface sheet side. It can be promptly drawn and diffused inside the absorbent body to efficiently absorb and hold, thereby exhibiting an excellent effect of suppressing wetness of the skin and providing a good wearing feeling.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway perspective view schematically showing a disposable diaper as a preferred embodiment of an absorbent article in the present invention from the skin contact surface direction. (A) is sectional drawing of the II-II line cross section shown in FIG. 1, (b) is a partially expanded sectional view which expands and partially shows the cross section of a surface sheet, (c) is surface. It is a partially expanded sectional view which shows typically the arrangement | positioning relationship of a sheet | seat and a covering sheet. It is a drawing substitute photograph which imaged the section of the disposable diaper of this embodiment. It is explanatory drawing which shows typically the relationship between the surface sheet in a back surface recessed part, a coating sheet, and an absorptive core. It is a perspective view which shows typically the surface sheet used for the diaper of embodiment by a partial cross section. It is the partially expanded sectional view which expanded and showed a part of predetermined | prescribed cross section of Fig.2-1 (a). It is explanatory drawing which shows typically the relationship between the back surface recessed part and back surface convex part in the non-skin contact surface side of a surface sheet by planar view. It is a drawing substitute photograph which imaged the section of the surface sheet of this embodiment. It is explanatory drawing which shows the modification of the cross-sectional shape of a back surface recessed part. It is explanatory drawing which shows the modification of the cross-sectional shape of a surface sheet. It is explanatory drawing which shows the modification of an absorptive core. It is explanatory drawing which shows typically the diffusion state of the liquid in an Example and a comparative example. It is explanatory drawing which shows typically the diffusion state of the liquid in an Example and a comparative example.

  FIG. 1 is a partially cutaway perspective view schematically showing a disposable diaper as a preferred embodiment of an absorbent article according to the present invention from the skin contact surface direction. The diaper shown in the figure is a tape-type disposable diaper, and is shown in a state where the diaper developed in a plane is bent slightly and viewed from the inside (skin contact surface side).

First, the outline | summary of the said disposable diaper 10 of this embodiment is demonstrated.
The disposable diaper 10 of the present embodiment includes a liquid-permeable top sheet 1 disposed on the skin contact surface side, a back sheet 2 disposed on the non-skin contact surface side, and absorption interposed therebetween. And a body 3. The absorbent body 3 has an absorbent core 31 and covering sheets 31 and 32. The skin contact side surface and the non-skin contact side surface of the absorbent core 31 have a flat shape. The skin contact surface side is covered with a covering sheet 32, the non-skin contact surface side is covered with a covering sheet 33, and both the covering sheet and the absorbent core 31 are spray-coated with a hot melt adhesive. Are joined intermittently. Moreover, the width direction edge part of both coating sheets is mutually joined by the both-sides edge outer side of an absorptive core.

  The back sheet 2 is in the unfolded state and has a substantially hourglass shape in which both side edges are bound inward in the center in the longitudinal direction (Y direction) to form the outer shape of the diaper. The outer shape of the diaper 10 is, as its developed state, an abdominal side F disposed on the abdomen side of the wearer in the longitudinal direction (Y direction), a back side R disposed on the back side, and a crotch C positioned therebetween. It is divided into and. The crotch C includes an area corresponding to the excretion part of the wearer (excretion part corresponding area). The back sheet 2 may be composed of a single sheet or a plurality of sheets. On the back sheet 2, the top sheet 1 and the absorber 3 are arranged so that the top sheet 1 covers the upper side of the absorber 3. Each of the top sheet 1 and the absorber 3 has a substantially rectangular shape that is narrower than the back sheet 2, and is arranged such that the longitudinal direction thereof coincides with the longitudinal direction of the back sheet 2. Furthermore, a pair of side sheets 4 and 4 are laminated | stacked toward the width direction (X direction) outward from the longitudinal direction both-sides edge of the surface sheet 1. FIG. A leak-proof cuff 41 provided with an elastic member is formed at the end of the side seat 4 near the center in the width direction, and leg gathers 42 provided with an elastic member are formed outward in the width direction. By these, it is possible to effectively prevent side leakage of liquid or the like in the hip joint part due to the movement of the infant. In the diaper 10 of this embodiment, you may provide a functional structure part, a sheet | seat material, etc. further.

  On the ventral side F and the back side R of the diaper 10, a back side flap 4 and a back side flap 2 are laminated and a back side flap portion 51 and a ventral side flap portion 52 are formed that project outward in the width direction. . A fastening tape 53 is provided on the back flap portion 51. The diaper can be mounted and fixed by applying the tape 53 to a tape application part (not shown) provided on the ventral flap part 52. At this time, the center of the diaper in the longitudinal direction is gently bent inward, and the absorbent body 3 is worn so as to run along the baby's buttocks and lower abdomen. As a result, excreta is absorbed and held in the absorber 3 accurately.

  Although details of the material of the top sheet 1, the back sheet 2, and the absorbent portion 3 will be described later, in this embodiment, the top sheet 1 quickly absorbs excreted body fluid and transmits it to the absorber, and the touch. From the viewpoint of goodness, a hydrophilic air-through nonwoven fabric is used. Further, as the back sheet 7, a breathable film having air permeability is used. About the absorber 3, the absorptive core 31 uses what was comprised from the pulp fiber and the superabsorbent polymer, and the coating sheets 32 and 33 use the highly hydrophilic raw material.

  In the present invention, unless otherwise specified, the surface in contact with the human body is referred to as the skin side surface or skin contact surface or surface, and the opposite surface is referred to as the non-skin surface or non-skin contact surface or back surface. Of these two surfaces, the side close to the skin side or the extending direction is called the skin side, the skin contact surface side or the surface side, and the side close to the non-skin surface or the extending direction is the non-skin side, non-skin It is called the contact side or the back side. The direction positioned on the front side of the human body when worn is referred to as the front, and its end is referred to as the front end, and the direction positioned on the rear is referred to as the rear, and the end is referred to as the rear end. The normal direction of the front or back surface of the absorbent article is called the thickness direction, and the amount is called thickness. Furthermore, in a plan view of the absorbent article, a direction from the abdominal side to the back side through the crotch is referred to as a longitudinal direction or a longitudinal direction, and a direction orthogonal to the longitudinal (longitudinal) direction is referred to as a width direction. The vertical direction typically coincides with the front-rear direction of the human body when worn.

  Next, with reference to FIGS. 2-1 and 2-2, the cross-sectional shape of the diaper 10 is demonstrated. 2-1 (a) is a cross-sectional view taken along the line II-II shown in FIG. 1, (b) is a partially enlarged cross-sectional view schematically showing a partially enlarged cross-section of the surface sheet, (C) is a partial expanded sectional view which shows typically the arrangement relation of a surface sheet and a covering sheet. FIG. 2-2 is a drawing-substituting photograph in which a cross-section of the disposable diaper 10 of the present embodiment is imaged. The entire cross-section is shown in the center photograph, of which one of the back surface recesses is enlarged and shown in the lower right. Yes. In the enlarged view of the back surface concave portion 7, the space portion 72 located below the portion (entrance portion 71) where the covering sheet enters is shown as a portion surrounded by a broken-line circle. In addition, the absorptive core 31 is a fiber assembly which consists of pulp fiber etc., and the outer surface has fine undulations, such as the fiber of an outer edge fuzzing. Therefore, in FIG. 2-1 (a), the outline of the outer shape of the absorbent core 31 is indicated by a two-dot chain line as an approximate range of the fiber assembly (the same applies to FIGS. 3 and 5).

As shown in FIG. 2A, the cross-sectional shape of the diaper 10 is such that the topsheet 1 and the covering sheet 31 have an uneven shape with respect to the absorbent core 31. With this shape, in particular, the structure formed by the back surface concave portion 7 and the member therebelow, it is possible to improve the liquid drawability, the liquid diffusibility inside the absorber, and the liquid immobilization speed, which will be described later. The cross-sectional shapes of the topsheet 1 and the covering sheet 31 will be further described with reference to FIGS. 2-1 (b) and (c).
As shown in FIG. 2-1 (b), on the non-skin contact surface side of the top sheet 1, a back surface recess recessed from the non-skin contact surface side (z ₂ ) to the skin contact surface side (z ₁ ). 7 is formed. A large number of the back surface recesses 7 are periodically arranged adjacent to each other at substantially equal intervals in the plane direction, and the non-skin contact surface side of the top sheet 1 has an uneven shape by this arrangement. That between the back surface recess comprises skin contact surface side from (z ₁₎ and the back surface convex portion 8 that protrudes to the non-skin facing side (z _2). Here, "a plurality of back surface recesses are arranged in a distributed manner adjacent to each other" means that a top portion 7a, which will be described later, which is the bottom of the recess of the back surface recess portion 7, and 7a adjacent to each other are arranged through the bottom portion 7c. Therefore, the individual back surface recesses 7 are arranged so as to diffuse in each direction in a plan view. A plurality of streak depressions are not arranged in parallel. In the present embodiment, a surface convex portion 78 is formed on the skin contact surface side of the top sheet 1 corresponding to the back surface concave portion 7, and on the skin contact surface side of the top sheet 1 corresponding to the back surface convex portion 8. A surface recess 88 is formed.
As shown in FIGS. 2-1 (c) and 2-2, a part of the covering sheet 32 that covers the skin contact surface side of the absorbent body 3 protrudes and enters the back surface concave portion 7 of the top sheet 1. A portion 71 is formed. When the covering sheet 32 and the absorbent core 31 are intermittently joined with a hot-melt adhesive as in the diaper 10 of the present embodiment, the covering sheet 32 is raised between the adhesives and the entry portion 71. It is preferable that Furthermore, as FIG. 2-1 (c) and FIG. 2-2 show, between the coating sheet 32 and the absorptive core 31 in the back surface recessed part 7, the space part 72 is formed. The space portion 72 is formed along with the formation of the entry portion 71 due to the protrusion of the covering sheet 32. The penetration depth (h ₂ ) of the entry portions 71, 71,... Is not necessarily uniform, and is not limited to a deep depth as shown in FIG. ₁ )> There may be an entry portion 71 having a penetration depth (h ₂ ) (see FIG. 2-1 (C)). In such a back surface concave portion 7, a gap is also formed between the top sheet 1 and the covering sheet 32, which is preferable as a buffer gap portion 73 that reduces the influence of the force from the top sheet 1 side.

The back surface recessed part 7 is a dent of the non-skin contact side surface of the top sheet 1, and is formed by a side wall part 7b from the top part 7a to the bottom part 7c formed by the top sheet 1 along the dent (FIG. 2-1). (See (b)). Since such a back surface recess 7 is made of a soft nonwoven fabric and cannot necessarily be defined as a perfect geometric figure, the cross-sectional shape of the back surface recess 7 formed by the side wall portion 7b has a shape similar to a parabola, and the space of the back surface recess 7 The shape is similar to a cone or a truncated cone having a round top portion 7a. Note that the three-dimensional shape of the back surface recess 7 is not limited to that of the present embodiment, and an arbitrary recess shape can be adopted. For example, a shape such as a cone or a column may be used. If there is an uneven shape on the skin contact surface side of the top sheet as in this embodiment, cones (cones, truncated cones, pyramids, truncated pyramids, slanted cones, etc.) according to the shape on the skin contact surface side ) Is preferable. In this embodiment, the top portion 7a is a part of the highest position of the non-skin contact side of the top sheet 1 which forms the inner wall of the three-dimensional space of the back surface recess 7 (Z ₁ direction), and the bottom 7c of the space of the site of lowest position (Z ₂ direction). Therefore, if the back surface concave portion 7 and the back surface convex portion 8 have an uneven shape that repeats alternately, the bottom portion 7 c of the back surface concave portion coincides with the top portion 8 a of the back surface convex portion 8. In addition, although the top part 7a and the bottom part 7c (the top part 8a of a back surface convex part) of the above-mentioned back surface recessed part 7 are shown as a vertex on a curved surface, the circumference | surroundings may be planar. In that case, the top portion 7a can be determined as the highest point in the center point or plane of the plane, and the bottom portion 7c (the top portion 8a of the convex portion on the back surface) can be determined as the lowest point in the center point or plane of the plane. In this definition, the depth (h ₁ ) of the back surface recess 7 refers to a difference in height of the non-skin contact side surface of the top sheet 1 and is a distance from the top 7a to the bottom 7c (FIG. 2-1 ( b)). Similarly, the depth (h ₂ ) of the entry portion 71 is a distance between the bottom portion 7c and the highest position on the skin contact surface side of the entry portion 71 (FIG. 2-1 (c)). reference).

Next, with reference to FIG. 3, the back surface recessed part 7 which is the basic structure part of this embodiment is further explained in full detail, and the effect is described. FIG. 3 is an explanatory view schematically showing the relationship between the top sheet 1, the covering sheet 32, and the absorbent core 31 in the back surface recess 7. In FIG. 3, two patterns (a) and (b) are shown. The pattern (a), the depth of the entry portion 71 _{(h 2)} is a recess depth of the backside recess 7 _{(h 1)} shallower than _(h 2 _<h 1), the depth with the space 72 _{(h 3} ) Is formed. In the pattern (b), (h ₁ = h ₂ ), and the space 72 is formed, but the buffer gap 73 is not formed.

In any of the patterns in FIGS. 3 (a) and (b), the back surface recess 7 is formed toward the non-skin contact surface side z ₂ of the topsheet 1 into skin contact surface side z ₁ Thus, an internal space of the liquid-retaining absorbent 3 under the surface sheet is formed at a position close to the wearer's skin. Thereby, the permeation | transmission distance of the liquid to internal space becomes short, and it is effective for the improvement of the absorptivity of a liquid. Furthermore, the presence of the entry portion 71 in the back surface concave portion 7 makes the highly hydrophilic coating sheet close to the skin, so that the rapid withdrawal of the excretory fluid into the absorbent core 31 can be ensured. From the viewpoint of this liquid drawing property, it is preferable that the side wall portion 7b and the entry portion 71 in the back surface concave portion 7 are in contact with each other and closely bonded to each other at the interface (hereinafter referred to as a bonding portion 74). Thereby, the approach part 71 can draw in the excretion liquid in the surface sheet 1 directly. There is a method of bonding with a hot-melt adhesive or the like as a method of forming the bonding portion 74, but it is preferable to perform point bonding between both fibers by spray coating or the like without forming an adhesive film. Thereby, the distance between the fibers of the side wall portion 7b (surface sheet 1) made of a liquid-permeable non-woven fabric is maintained, the liquid can be quickly transmitted, and the entry portion 71 (covering sheet 32) made of a highly hydrophilic material. ) Becomes a suction force of the liquid, and the liquid can be directly taken into the inside, that is, the absorbent core 31. Such a structure between the members in the back surface concave portion 7 is preferably arranged at least in the crotch portion C of the diaper 10 from the viewpoint of quickly drawing out the excretory fluid without diffusing.

In order to make the above-mentioned liquid drawing-in property effective, the depth (h ₂ ) of the entry portion 71 is 50% or more with respect to the depth (h ₁ ) of the back surface recess 7. Is preferable, and it is more preferable that it is 75% or more. By setting it as the said minimum or more, the liquid remaining amount of the top part 7a of the surface sheet 1 can be reduced especially. In practice, the depth (h ₂ ) of entry of the entry portion 71 into the back surface recess 7 is not necessarily uniform in each back surface recess 7, or in some cases, the back surface recess where the entry portion 71 is not substantially formed. 7 may be broken. In this case, it is preferable that the number of the depth (h ₂ ) of the entry portion 71 to be 50% or more in the entire back surface recess is 50% or more, and more preferably 70% or more. By setting it to the above lower limit or more, the amount of liquid that touches the skin after liquid absorption can be reduced.

Furthermore, the pattern (a) in the above-mentioned preferable range and satisfying (h ₂ <h ₁ ) is preferable because an inherent action can be exerted by the presence of the buffer gap 73 while realizing improvement of the drawability of the liquid. . Specifically, the influence of the force applied from the top sheet 1 side on the absorber 3 can be reduced. Moreover, since the top part 7a of the back surface recessed part 7 in the position closest to the skin is not in contact with the entry part 71, the liquid return can be suppressed even if the entry part 71 contains moisture, and the top sheet 1 can be satisfactorily dried. A feeling can be realized. On the other hand, the pattern (b) which satisfies (h ₂ = h ₁ ) is preferable from the viewpoint of the drawability of the liquid because the entry part 71 enters from the side wall part 7b to the top part 7a. Accordingly, the ratio (a) / (b) between the (a) pattern and the (b) pattern in the entire back surface recess 7 formed in the top sheet 1 is (b) in the vicinity of the urine portion where the liquid draw-in property is important. ) It is preferable that the ratio of the pattern is high, and it is preferable that the ratio of the pattern (a) is high in the vicinity of the buttocks where emphasis is placed on liquid return suppression. The ratio (a) / (b) between the (a) pattern and the (b) pattern of the back surface recess 7 formed on the top sheet in the vicinity of the urination portion is 4/6 to 0 from the viewpoint of emphasizing liquid drawability. / 10 is preferable, and 2/8 to 0/10 is more preferable. The ratio (a) / (b) between the (a) pattern and the (b) pattern of the back surface recess 7 formed on the top sheet 1 in the vicinity of the collar portion is 6/4 to 10 from the viewpoint of emphasizing liquid return suppression. / 0 is preferable, and 8/2 to 10/0 is more preferable.

  As described above, the space portion 72 is formed in the back surface recess 7 ((a) and (b) of FIG. 3). The space part 72 can diffuse the excretion liquid drawn in by the entry part 71 inside the absorbent body 3 and directly and efficiently absorb it on the wide surface of the absorbent core. Thereby, the absorption speed | rate of the excretion liquid from the surface sheet 1 can improve, and the spreading | diffusion of the liquid by the skin contact surface side of the surface sheet 1 can be suppressed. Further, even when the amount of excreted liquid excreted becomes large at one time, the space 72 can temporarily hold the liquid from the top sheet 1 and serve as a liquid absorption adjusting valve. And since the space part 72 has low water retention power unlike the absorptive core 31 which consists of pulp fiber etc., a liquid can be quickly delivered to the absorptive core 31. FIG. Thus, since the space part 72 can recover the space immediately while holding the temporary liquid as a liquid regulating valve, not only in the case of a large amount of excretion but also in the case of repeated excretion sufficiently Is possible. Moreover, if the skin contact side surface of the absorptive core 31 is a substantially flat shape, the effect | action of this space part 72 will become more effective, and it is preferable. However, the skin contact side surface of the absorbent core 31 does not have to be smooth, and fluff of pulp fibers (see the inner circle in FIG. 2-1 (a)) reaches the space 72. It is preferable that the liquid is quickly transferred to the absorbent core.

(The depth of the backside recess 7 _(h 1), the depth of the entry portion 71 _(h 2), and the depth of the buffer clearance 73 (method of measuring _{h 3))}
The depth (h ₁ ) of the back surface recess 7 is measured by enlarging the cross section of the top sheet 1 passing through the top 7a and the bottom 7c, and the tangent t (see FIG. 2-1 (c)) of the adjacent bottom 7c and the top 7a. This is done by measuring the distance to the. The depth (h ₂ ) of the entry portion 71 is measured by measuring the distance between the top portion 71a of the skin contact surface side convex portion of the entry portion 71 and the tangent line of the bottom portion 7c. The difference was defined as the depth (h ₃ ) of the buffer gap 73. _{(H 3 = h 1 -h 2} ). For measurement, enlargement with a VH-3000 microscope manufactured by Keyence and measurement by a two-point measurement method after calibration setting were performed. An electron microscope may be used.

As described above, the diaper 10 has a structure having both a high liquid drawing force of the back surface concave portion 7 and the entry portion 71 and an efficient liquid delivery property of the space portion 72. That is, the structure of the back surface recess 7, the entry portion 71 of the covering sheet 32, the space portion 72, and the absorbent core 31 works in cooperation with the absorbent core 31 inside the absorbent body while suppressing liquid diffusion on the skin side surface. By diffusing the liquid, the liquid can be securely held and fixed. Thereby, the liquid residue and liquid return by the surface sheet 1 side are suppressed, and the favorable dry feeling to a wearer's skin is realizable.
Moreover, in the absorptive core 31 which can absorb and hold a liquid on a wide surface, the reach area of the liquid to the back sheet 2 side also becomes wide, and it becomes possible to discharge moisture from the back sheet 2 to the outside efficiently. . As a result, the lowering of the diaper temperature due to the heat of vaporization of moisture is realized on a wide surface on the back sheet 2 side, and moisture transpiration inside the diaper 10 (the part surrounded by the back sheet 2 and the skin of the wearer) is effective. Therefore, the diaper 10 can be prevented from becoming more stuffy.

In order to realize the above-described effects, the ratio (r ₁ ) between the distance (r ₁ ) between the bottom 7c and the bottom 7c in the back surface recess 7 and the depth (h ₁ ) of the back surface recess as shown in FIG. ₁ / h ₁ ) is preferably 1/1 to 3/1, and more preferably 10/8 to 10/4. Further, the ratio (w ₁ / h ₁ ) between the pitch (w ₁ ) between the top portions 7a-7a of the back surface recess and the depth (h ₁ ) of the back surface recess is preferably 1/1 to 3/1. 8-10 / 4 is preferable. By setting it as the said lower limit or more, it can be set as the surface sheet structure where a coating sheet enters easily, and the volume of the space 72 can be ensured large by setting it as the said upper limit or less.

  In the topsheet 1, as described above, the back surface convex portions 8 are formed between the back surface concave portions 7 and 7, and the back surface convex portions 8 preferably have a top portion 8a. In the back surface convex part 8, as shown in FIG. 3, the surface sheet 1 and the absorptive core 31 are made the contact in the top part 8a via the coating sheet 32, and this contact area can be suppressed suitably. By suppressing the contact area with the absorbent core 31, liquid diffusion on the absorbent core 31 is smoothed and the absorption speed is shortened, and liquid return to the surface sheet 1 side after liquid absorption is suppressed. Combined with the structure in the back surface recess 7, it is further effective in suppressing wetting on the top sheet 1.

  Furthermore, in the surface sheet 1, it is preferable that the skin contact surface side is an uneven | corrugated shape which the surface convex part 78 and the surface recessed part 88 repeat according to the undulation of the back surface recessed part 7 and the back surface convex part 8. FIG. It is preferable that a plurality of the concave and convex shapes integrated with the front and back are arranged in the plane direction so that the surface sheet 1 as a whole is formed with repeated irregularities in multiple directions (see FIG. 4). The shape of the topsheet 1 can not only reduce the contact area between the absorbent core 31 and the topsheet 1, but also reduce the contact area between the wearer's skin and the topsheet 1. This reduction of the contact area is more effective in suppressing skin wetting, and the air permeability is improved in the uneven portion, which is more effective in preventing stuffiness. Moreover, if the surface sheet 1 is uneven | corrugated shape on both surfaces, the three-dimensional cushioning property which will follow a three-dimensional movement well and will be supported by a point on both surfaces will express. If the top portion 78a of the surface convex portion 78 is a rounded curved surface shape, a soft touch feeling can be obtained in combination with this cushioning property.

In addition, as shown in FIG. 4, the concave and convex shape of the top sheet 1 is formed with a side wall surface 88b (= 78b) inclined downward from the top convex portion 78 to the top concave portion 88, and the top concave portion 88 is independent. It is preferably in a mortar shape or a cup shape. Thereby, the collection property of excretion fluid and the improvement of the liquid absorption performance become more effective. This point will be described with reference to FIG. FIG. 5 is a partially enlarged cross-sectional view showing a part of the predetermined cross section of FIG. 2-1 (a) in an enlarged manner. In addition, with respect to the concave and convex rows (k ₁ row) shown as the cross section, for the concave and convex rows (k ₂ row), the back surface convex portion is omitted for the sake of understanding the liquid permeation and the back surface convex portions are omitted. Only the part is shown. In the present embodiment, for example, the excretory fluid a ₁ tends to accumulate near the top portion 88a of the surface concave portion 88 below the side wall portion 78b (= 88b) rather than the top portion 78a of the surface convex portion 78 (arrow b ₁ ). It becomes difficult to move to. Thereby, the diffusibility of the excretion liquid on the skin contact surface side of the top sheet 1 can be further suppressed, and the excretion liquid can be moved to a position far from the skin in the thickness direction. Further, the excretory fluid that has moved to the front surface recess 88 is sucked from the side wall portion 88b (= the side wall portion 7b of the back surface recess portion 7) to the entry portion 71 via the internal joint portion 74 (b ₂ ), and into the space portion 72. Be drawn. And from the space 72 in the planar direction liquid is diffused (arrow b _3), is passed to the absorbent core 31 (arrow b ₄₎ are immobilized. Incidentally, the arrow b ₂ to b ₄ is a mechanism of action for the back surface recess is a basic structural part of the foregoing. Thus, the uneven shape of the front surface convex part 78 and the front surface 88 can make the function of the back surface concave part 7 more effective.

  On the non-skin contact surface side of the topsheet 1, the individual back surface protrusions 8 are surrounded by a plurality of back surface recesses 7 and are arranged independently from each other in the plane direction, and each back surface recess 7 has a space in the plane direction. It is preferable that they are connected to each other. The above-described independent arrangement is not limited to the case where the rear surface protrusions 8 and 8 are completely separated from each other, and includes those that are partially connected if at least the periphery of the top 8a is separated. . This preferred arrangement will be described with reference to FIG. FIG. 6 is an explanatory diagram schematically showing the relationship between the back surface concave portion and the back surface convex portion on the non-skin contact surface side of the top sheet in a plan view, and is simplified and modeled based on the arrangement relationship of the top portions 7a and 8a. It shows. Specifically, the top portion 7a of the back surface concave portion 7 is shown as a white circle, and the top portion 8a of the back surface convex portion 8 is shown as a black circle. In FIG. 6, the respective regions between the top 8a and the top 7a and the top 8a, between the top 7a and the top 7a, and between the top 8a and the top 8a are side walls. Among them, the side wall portion in the region between the top portion 8a and the top portion 8a is indicated by a long and slender hourglass-shaped figure and has a symbol m for understanding of the preferable arrangement. In addition, the said side wall part is a part which forms the back surface recessed part 7 and the back surface convex part 8 continuously, and means both the above-mentioned side wall parts 7b and 8b.

As shown in FIG. 6, the side wall part m is distribute | arranged between the top part 8a-top part 8a of the back surface convex part 8. As shown in FIG. The side wall portions m is not a shape that connects the top portion 8a of the back protrusion 8 completely, as an elongated hourglass shape shown in FIG. 6, z ₂ in the sheet thickness direction (Fig. 2-1 (b) at the center thereof it is preferable from a shape having a constricted z ₁ direction). The back surface convex portions 8 and 8 are incomplete but divided and become independent at the constricted portion, and the back surface concave portion 7 is connected to the space at the constricted portion of the side wall portion m. That is, on the non-skin contact surface side of the topsheet 1, not only between the top 8a-top 7a-top 8a but also between the top 8a-top 8a is uneven, so that the back surface recesses 7, 7 are A connecting space will be formed. For example, as shown in FIG. 7, the side wall part m is preferably formed in an arch shape. The space of each back surface concave portion 7 along the arch shape of the side wall portion m is in a state where it can freely come and go as indicated by the white arrows shown in FIG. 6 and FIG. If the topsheet 1 is in this preferable shape, the entrance portion 71 of the covering sheet 32 is formed along this shape, and the space portions 72 below the entrance portion 71 are connected to each other. As a result, the excreted liquid drawn into the space 72 can be freely diffused by separating the support of the back recess 7 as shown by the white arrows shown in FIGS. The excretory fluid can be efficiently absorbed and retained and immobilized on a wide surface.

3 and 5 of the diaper 10, it is preferable that there is a density difference or density gradient in which the fiber density of the nonwoven fabric of the top sheet 1 in the back surface concave portion increases from the top 7 a to the bottom 7 c. By doing so, the liquid can be quickly transmitted from the skin contact surface side, and the liquid can be drawn into the inside more strongly. For example, in the predetermined cross section of the back surface concave portion 7 shown in FIG. 2-1 (b), the density difference and the density gradient are obtained by changing the top sheet 1 extending from the top portion 7a to the bottom portion 7c to the height (h ₁ ) of the back surface concave portion 7. It can be shown by equally dividing (A part, B part, C part), and comparing the average of each fiber density (n ₁ , n ₂ , n ₃ ) in these parts. The fiber density of part A, part B and part C is preferably (n ₁ ) <(n ₂ ) <(n ₃ ), and the ratio (n ₁ / n ₂ / n ₃ ) is 2/6/10 8/9/10 is preferable, and 3/5/10 to 5/7/10 is more preferable. By setting it as the said lower limit or more, the good touch can be ensured, and the liquid residue of the surface sheet 1 can be reduced by setting it as the said upper limit or less.

(Density measurement method)
The density (n ₁ , n ₂ , n ₃ ) of the top portion 7a, the side wall portion 7b, and the bottom portion 7c of the top sheet 1 in the above-described back surface recess 7 can be measured by the following method.
Based on the depth (h ₁ ) in the back surface recess 7, the top sheet 7 from the top 7 a to the bottom 7 b is divided into three equal parts, A part, B part, and C part, and the top part 7 a and bottom part of the top sheet The cut surface passing through 7b is magnified using the following scanning electron microscope (adjusted to a magnification capable of measuring 30 to 60 fiber cross-sections; 150 to 500 times) and cut by the cut surface per fixed area. The number of cross sections of the fibers was counted. Next, it was converted into the number of cross-sections of the fibers around 1 mm ² , and this was defined as the fiber density (lines / mm ² ). The measurement was performed at three locations, and the fiber density of the sample was averaged.
Scanning electron microscope: JCM-5100 (trade name) manufactured by JEOL Ltd.

(Modified example of cross-sectional shape of back surface recess and top sheet)
In the diaper 10, the cross-sectional shape of the back surface recess 7 is not limited to the above-described form (see FIG. 2-1 (b)), and may be any shape as long as it has the above-described liquid absorbability. For example, as shown in FIG. 8, the top 7a has a spire shape (a), the top 7a has a plurality (b), the top 7a is flat (c), and the top 7a is between the side walls 7b and 7b. (D) etc. which are swollen with respect to the width of. Similarly, the cross-sectional shape of the top sheet 1 is not limited to the concavo-convex shape of the present embodiment, and any shape can be used as long as it allows the disposition relationship between the back surface recess and the covering sheet 32 and the absorbent core 31 thereunder. It can be a shape. For example, as shown in FIG. 9, a shape (a) where the skin contact surface side is flat, a shape (b) where the back surface concave portions 7, 7 are spaced apart and the top portion of the back surface convex portion is flat, and the like. In the case of the shape as shown in FIG. 9B, the bottom portion 7 c of the back surface concave portion 7 is an intersecting portion between the plane where the top portion 8 a of the back surface convex portion 8 is located and the aspect of the side wall portion 7 b of the back surface concave portion 7.

(Modification of absorbent core)
Furthermore, in the diaper 10, the shape of the absorbent core is not limited to the shape in which the skin contact side surface of the present embodiment is flat, but the liquid taken into the inside can be diffused widely and quickly absorbed and held and fixed. Can be arbitrarily adopted. For example, as shown in FIG. 10, a groove-shaped concave portion 91, a block-shaped protruding absorbing portion 93 divided into the concave portions, and a concave portion absorbing portion 94 that connects one surface side of the protruding absorbing portion 93 corresponding to the concave portion 91. And absorbent core 90 (FIG. 10A), 90a (FIG. 10B), and the like. When this absorbent core is used, the liquid drawn into the space 72 is diffused along the concave portions 91 and the concave portion absorbing portions 94 thereunder, dispersed in the protruding absorbing portions 93, absorbed, held, and fixed. . Since the liquid is reliably fixed in a wide range by such a path, the liquid does not easily return to the surface sheet side. Furthermore, in the absorbent cores 90 and 90a, when the concave portion absorbing portion 94 has a lower basis weight than the protruding absorbent portion 93, the liquid passage resistance in the concave portion absorbing portion 94 is reduced, and liquid diffusion is easy. Further, the liquid retainability is reduced, and the liquid is easily transferred to the protruding absorption portion 93. From the same viewpoint, it is preferable that the low-basis weight recessed portion absorbing portion 94 has a lower density than the high-basis weight protruding absorbing portion 93. The absorbent cores 90 and 90a may have either the surface with the concave portion 91 or the surface of the concave portion absorbent portion 94 with a low basis weight on the skin contact surface side, and may be arbitrarily selected depending on the purpose of the absorbent article. It can be arranged.
When this absorptive core 90 or 90a is adopted, it is preferable that the concave portion 91 or the concave portion absorbing portion 94 overlaps the space portion 72 of the back surface concave portion 7 in the crotch portion C including at least the excretory portion corresponding region. As a result, the liquid in the space portion 72 is easily transferred to the concave portion 91 or the concave portion absorbing portion 94, and is easily diffused and fixed.

(Formation method of the back surface recessed part 7 and the approach part 71)
The absorbent article which has the back surface recessed part 7 and the approach part 71 as shown to FIGS. 2-2 can be obtained in the normal manufacturing process in this kind of article. For example, in the process of assembling the diaper, the topsheet 1 is added between the pressure roll in which the concavo-convex portion is formed and the anvil roll disposed opposite to the pressure roll in the lamination step of the absorber and the topsheet. It can be formed by introducing the laminate and partially pressing and heating it so as to hit a pressure roll. At that time, it is preferable that the hot melt adhesive is intermittently bonded by slot spray coating, spiral coating, or the like so that the nonwoven fabric of the top sheet 1 and the covering sheet are in close contact with each other and a back surface recess is formed. Moreover, it is preferable to adhere more loosely between the covering sheet and the absorbent core by spiral coating or the like. The adhesive application density (q ₁ ) between the surface sheet and the cover sheet is preferably higher than the application density (q ₂ ) of the hot melt adhesive between the cover sheet and the absorbent core. The ratio of (q ₁ / q ₂ ) is preferably 2/1 to 10/1, more preferably 3/1 to 5/1. Furthermore, when forming a back surface recessed part with the said pressure roll, using the shaping sheet | seat which has an uneven | corrugated shape as shown in FIG. 4 and an uneven | corrugated shape as shown in FIG. 9 further, and what has the fluff of a fiber as a coating sheet, If there is a wrinkle or a wrinkle and a stretchable one is used, the adhesion between the topsheet 1 and the entry portion 71 in the back recess is further improved, and the entry portion 71 that has entered deeper can be formed.

The shaped sheet can be produced as follows. The fiber web before being fused is supplied from the card machine to the web shaping device so as to have a predetermined thickness, and the fiber web is fixed on a pedestal having a large number of protrusions and air permeability. Next, hot air is blown onto the fiber web on the pedestal at a temperature at which each fiber can be appropriately fused to shape the fiber web along the protrusions on the pedestal, and the fibers are fused. The temperature of the hot air at this time is preferably 0 to 70 ° C higher than the melting point of the thermoplastic fiber constituting the fiber web, and more preferably 5 to 50 ° C higher. Examples of the thermoplastic fiber include polyolefins such as polypropylene and polyethylene, polyesters, polyamides such as nylon 6 and nylon 66, polyacrylonitriles, etc., or a core-sheath type or a side-by-side type composite composed of two or more of these. A fiber etc. can be mentioned. When a composite fiber containing a low melting point component and a high melting point component is used as the thermoplastic fiber, the temperature of the hot air blown onto the fiber web is preferably equal to or higher than the melting point of the low melting point component and lower than the melting point of the high melting point component. The temperature of the hot air blown onto the fiber web is more preferably the melting point of the low melting point component + 0 ° C. to the melting point of the high melting point component −10 ° C., and the melting point of the low melting point component + 5 ° C. to the melting point of the high melting point component −20 ° C. More preferably. The fiber web and the nonwoven fabric preferably contain 30 to 100% by mass of thermoplastic fibers, and more preferably 40 to 80% by mass. The fiber web and the nonwoven fabric may contain fibers that do not inherently have heat-fusibility (for example, natural fibers such as cotton and pulp, rayon, and acetate fibers).
The wind speed of the hot air when shaping the fiber web is more preferably 20 to 130 m / sec, more preferably 30 to 100 m / sec, from the viewpoints of shapeability and texture. When the wind speed is equal to or higher than this lower limit, the three-dimensional effect is sufficient, and the effects of cushioning and excrement collection are sufficiently exhibited. When the wind speed is less than or equal to this upper limit value, the sheet does not open and the compression resistance is maintained well, which is preferable because the effects of cushioning and excrement collection can be sufficiently exhibited.
In consideration of continuous production, there is a mode in which the pedestal is a conveyor type or drum type that can be conveyed, and the typed nonwoven fabric that is conveyed is wound up by a roll. Note that the MD direction and the CD direction may be directed to the nonwoven fabric of this embodiment.

As a material for forming the top sheet 1, the back sheet 2, the absorbent body 3, and the side sheet 4, those normally used for absorbent articles can be used.
As the surface sheet 1, for example, a hydrophilic non-woven fabric is preferable, and an air-through non-woven fabric, a point-bonded non-woven fabric, a spun-bonded non-woven fabric, a spunlace non-woven fabric, a non-woven fabric called a three-dimensional shaped non-woven fabric, and the fibers are natural fibers such as cotton. Polypropylene single fiber, polypropylene / polyethylene composite fiber, polyethylene terephthalate / polyethylene composite fiber and the like are preferably subjected to hydrophilic treatment, and those having a basis weight of 15 to 50 g / m ² can be suitably used. Further, a hydrophilic perforated film or a hydrophilic nonwoven fabric may be partially overlapped on the crotch portion of the topsheet 1 on the non-skin surface side of the topsheet 1.

  The back sheet 2 is not particularly limited as long as it is waterproof and moisture permeable, for example, but is, for example, a hydrophobic thermoplastic resin, a fine inorganic filler made of calcium carbonate or the like, or an organic high compatibility material. Examples include a porous film obtained by melt-kneading molecules and the like to form a film, and uniaxially or biaxially stretching the film. Examples of the thermoplastic resin include polyolefin. Examples of the polyolefin include high to low density polyethylene, linear low density polyethylene, polypropylene, polybutene and the like, and these can be used alone or in combination.

As the absorber 3, what is normally used for an absorbent article can be used. Specifically, as the absorbent core, for example, a fiber assembly or a combination of this and a superabsorbent polymer can be used. As the fibers constituting the fiber assembly, hydrophilic natural fibers such as pulp fibers, synthetic fibers (preferably subjected to hydrophilic treatment), and the like can be used. The basis weight is not particularly ^limited, preferably ^{150g / m 2 ~500g / m 2} .
In addition, as a covering sheet for covering the absorbent core, for example, thin paper (thin paper) such as hydrophilic tissue paper, crepe paper, nonwoven fabric made of hydrophilic fibers such as cotton and rayon, and synthetic resin fibers are hydrophilized. A non-woven fabric formed by treatment, for example, an air-through non-woven fabric, a point bond non-woven fabric, a spunlace non-woven fabric, a spunbond non-woven fabric, a spunbond-meltblown-spunbond (SMS) non-woven fabric or the like can be used.

  As the side sheet 4, for example, a water-repellent nonwoven fabric is preferable, and specifically, a spunbond nonwoven fabric, a spunbond-meltblown (SM) nonwoven fabric, a spunbond-meltblown-spunbond (SMS) nonwoven fabric, or the like is used. As an elastic member for three-dimensional gathers and an elastic member for leg gathers of the side sheet 4, normal elastic members used for this type of article can be used. For example, as materials, styrene-butadiene, butadiene, isoprene, neoprene, etc. Synthetic rubber, natural rubber, EVA, stretchable polyolefin, polyurethane, etc., and the form is a thread-like or string-like shape (flat rubber, etc.) having a rectangular, square, circular, or polygonal cross section, or A multifilament type filament or the like can be used.

In the absorbent article of the present invention, the absorbent core is not limited to that of the above-described embodiment as long as it has a function of absorbing and retaining liquid therein, and is, for example, a sheet-like thin article. May be. In the absorbent article of the present invention, the covering sheet is limited to that of the above embodiment as long as it has a function of covering at least the skin contact surface side of the absorbent core and delivering the liquid to the absorbent core. For example, it may be a member having liquid diffusion performance, and may be not only a single layer but also a plurality of layers.
The absorbent article of the present invention is not limited to the deployable disposable diaper of the above-described embodiment, and includes, for example, a pants-type disposable diaper and a pants-type disposable including those having a relationship between a topsheet, a covering sheet, and an absorbent core. It may be a diaper that can be used as a tape when partly broken, and may be a urine collection pad, sanitary napkin, panty liner, or light incontinence pad. The absorbent article of the present invention is effective not only for menstrual blood but also urine, olimono, loose stool and the like. Moreover, the absorbent article of the present invention may incorporate other members as appropriate in accordance with the use and function of the present embodiment.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited thereto.

[Example 1]
A web-forming device is fixed with a core-sheath composite fiber web having a core of polyethylene terephthalate and a sheath of polyethylene, and hot air is blown onto the fiber web on the pedestal so that the fiber web is moved along the protrusions on the pedestal. Both the front and back surfaces are shaped by fusing each fiber together with shaping (pitch (w ₁ ) between the tops 7a-7a of the back surface recesses 5mm and the depth (h ₁ ) of the back surface recesses 2mm). A shaped sheet having the shape shown in 4 was formed and used as a top sheet. A liquid-impermeable back sheet, an absorbent core (pulp basis weight 200 g / m ² , superabsorbent polymer basis weight 286 g / m ² ) are coated with hydrophilic paper in this order, and the top sheet is laminated in this order. Bonded with melt. The back sheet, the absorbent body shape, and the configuration were the same as the current commercially available diaper “Merry's Sarasara Air Through M Size” (trade name) manufactured by Kao Corporation. At this time, the adhesive application density (q ₁ ) between the top sheet and the cover sheet is 15 g / m ² , and the hot melt adhesive application density (q ₂ ) between the cover sheet and the absorbent core is 5 g / m ² . It was m ^2. The laminated sample was sealed at a diaper product pack pressure and stored at room temperature for 1 month to form an intrusion portion of the covering sheet.
The back surface recess depth (h ₁ ) was 1.5 mm on average. Moreover, the penetration depth (h ₂ ) of the entry portion was 1.3 mm on average. The ratio of the back surface concave portions in which (h ₂ ) / (h ₁ ) was 50% or more was 95%. Moreover, the ratio of what completely (100%) entered among the back surface recessed parts in which (h ₂ ) / (h ₁ ) is 50% or more was 60%.

[Example 2]
The laminated sample of Example 1 was sealed at a diaper product pack pressure and stored at room temperature for 3 days.
(1) The depth (h ₁ ) of the back surface recess was an average of 2.0 mm.
(2) Moreover, the penetration depth (h ₂ ) of the entry portion was an average of 0.8 mm.
(3) The ratio of the back surface concave portion in which (h ₂ ) / (h ₁ ) is 50% or more was 30%.
(4) Of the back surface concave portions in which (h ₂ ) / (h ₁ ) is 50% or more, the ratio of those completely (100%) entering was 5%.

[Comparative Example 1]
A sample of Comparative Example 1 was a hand-made product having the same specifications as that of a commercially available disposable diaper (trade name “Merry's Sarasara Air Through M size”) manufactured by Kao Corporation.

[Comparative Example 2]
A flat air-through nonwoven fabric composed of a core-sheath type composite fiber having a core of polyethylene terephthalate and a sheath of polyethylene was used as the top sheet, and the liquid-impervious back sheet, absorbent core (pulp basis weight 200 g / m ² , superabsorbent polymer basis weight 286 g / m ² ) were laminated in the order of an absorbent body coated with hydrophilic paper and a surface sheet, and each was bonded by hot melt. Take out only the pedestal of the device for shaping the fiber web described above, place it on the sample surface sheet so that the pedestal protrusion is in contact with the surface sheet side, pressurize it, and let it stand for one month. A shape was formed to obtain a sample of Comparative Example 2.

[Performance evaluation]
About the sample (disposable diaper) of an Example and a comparative example, the liquid diffusion area in each layer of a surface sheet, a coating sheet, and an absorptive core was measured. As the measurement test, the following two types of tests (1) and (2) were performed. The liquid diffusion in the absorbent core is a diffusion region of red artificial urine obtained by placing a projection device under a sample and transmitting the light when irradiated.
(Test 1)
First, for each of the samples of Examples 1 and 2 and Comparative Examples 1 and 2, the central part of the absorbent body in the width direction at a length of 155 mm in the longitudinal direction from the end of the ventral absorbent body of the sample developed in a plane. As a liquid injection point, 40 g of artificial urine was injected at a rate of 5 g / sec using a pump. The composition of artificial urine is 1.94% by weight of urea, 0.795% by weight of sodium chloride, 0.11% by weight of magnesium sulfate, 0.062% by weight of calcium chloride, 0.197% by weight of potassium sulfate, red No. 2 (dye ) 0.010% by weight, water 96.88% by weight and polyoxyethylene lauryl ether (about 0.07%), and the surface tension was adjusted to 53 ± 1 dyne / cm (23 ° C.). After leaving still for 10 minutes, the surface sheet was peeled off and photographed, and the diffusion area of the artificial urine was copied onto the OHP sheet. The absorber upper covering sheet after the surface sheet was peeled off was similarly photographed, and the diffusion area of the artificial urine was copied onto the OHP sheet. The artificial urine diffusion region obtained by placing the sample on the projection table and irradiating and transmitting light from the back sheet side was copied onto the OHP sheet. The image of the OHP sheet was captured by a scanner, and the diffusion area was calculated using image analysis software Image-Pro Plus (manufactured by Nippon Roper).

(Test 2)
About each sample of Example 1 and Comparative Example 1, the pump was formed using the central part of the absorbent body in the width direction at 155 mm in the longitudinal direction from the end part of the abdominal side absorbent body of the sample developed in a plane as the liquid injection point. 40 g of artificial urine was injected at a rate of 5 g / sec. After standing for 10 minutes, a photograph was taken from above, and 40 g of artificial urine was injected at a rate of 5 g / sec from the same injection point. After standing still for 10 minutes, the diffusion area was analyzed in the same manner as in Test 1. In Test 2, it is impossible to analyze the diffusion area after injection of 40 g. In Test 2, it was confirmed by a photographic image taken before the second artificial urine injection that the artificial urine diffusion state on the surface sheet by the first artificial urine injection was the same as the sample of Test 1.

  The evaluation results are shown in Tables 1 and 2 below. Moreover, the diffusion range of the sample liquid used in the liquid diffusion test is shown in FIGS. Table 1 and FIG. 11 show the measurement results of (Test 1), and Tables 2 and 12 show the measurement results of (Test 2). The values of 40 g injection in Table 2 and FIG. 12 are the values of Example 1 and Comparative Example 1 implemented in Test 1 arranged for comparison. In FIGS. 11 and 12, the liquid diffusion range of the top sheet is shown as a part with a black circle on the photographed substitute photograph, and the liquid diffusion range of the covering sheet and the absorbent core is shown as a part surrounded by a black line. ing. The change in the liquid diffusion area between the layers in each sample shown in FIGS. 11 and 12 and the difference in area between Examples 1 and 2 and Comparative Examples 1 and 2 correspond to the measurement results in Tables 1 and 2. It is.

As is clear from the results shown in Table 1 and FIG. 11, the disposable diapers of Examples 1 and 2 have suppressed the diffusion of the liquid in the surface sheet as compared with Comparative Example 1, while In the internal structure under the surface sheet such as the covering sheet and the absorbent core, the liquid diffusion is sufficiently performed as in the comparative example. Furthermore, as is clear from the results shown in Table 2 and FIG. 12, the disposable diaper of Example 1 is a liquid diffusion area on the surface sheet in two liquid injections in Test 2 and only one liquid injection in Test 1. Was confined to substantially the same size. Moreover, the disposable diaper of Example 1 was fully diffused according to the liquid accumulation amount inside the absorber, although the liquid diffusion of the surface sheet was suppressed. On the other hand, in the comparative example, the liquid diffusion area of the top sheet after the two liquid injections in Test 2 was about twice as large as that of the single liquid injection in Test 1.
Based on the above, the disposable diaper of the example efficiently absorbs the liquid by drawing it in quickly by suppressing the diffusion of the liquid in the surface sheet, regardless of the amount of liquid such as repeated excretion. It has been found that it has an excellent effect of suppressing wetness of the skin and providing a good feeling of wearing.

DESCRIPTION OF SYMBOLS 1 Surface sheet 2 Base sheet 3 Absorber 31 Absorbent core 32, 33 Cover sheet 7 Back surface recessed part 71 Entry part (entrance part of cover sheet)
72 Space part 73 Buffer gap part 74 Joint part 8 Back surface convex part 78 Surface convex part 88 Surface convex part 10 Absorber

Claims (10)

An absorbent article having a liquid-permeable surface sheet disposed on the skin contact surface side, a back sheet disposed on the non-skin contact surface side, and an absorbent body interposed between the both sheets,
The surface sheet is made of a nonwoven fabric, and the absorbent body has an absorbent core composed of pulp fibers and a covering sheet covering the absorbent core,
The non-skin contact surface side of the topsheet, plurality of skin back surface recess recessed into contacting side, adjacent, are distributed scattered to diffuse in each direction in a plan view ,
The absorbent cover sheet enters the back recess, and between the cover sheet and the absorbent core that has entered, a space as an internal space of the absorber enters the back recess of the top sheet, An absorbent article in which pulp fibers of the absorbent core are fluffed inside the space .   The absorbent article according to claim 1, wherein the non-skin contact surface side of the top sheet has an uneven shape due to a periodic arrangement of the back surface recesses.   The absorptive article according to claim 1 or 2 whose skin contact surface side of said surface sheet is uneven.   The absorbent article according to any one of claims 1 to 3, wherein the skin contact surface side of the absorbent core has a flat shape.   The absorbent article according to any one of claims 1 to 4, wherein a depth of penetration of the covering sheet in the back surface recess of the top sheet is 50% or more of a recess depth of the back surface recess.   The absorptive article according to any one of claims 1 to 5 which has a crevice between said surface sheet and the portion which said cover sheet entered in said back surface crevice. The said back surface recessed part has the top part which consists of a surface sheet, a side wall part, and a bottom part, and there exists a part with which the surface sheet of the said side wall part and the coating sheet which entered the said back surface recessed part are joined. The absorbent article of Claim 1.   A plurality of back surface concave portions and a plurality of back surface convex portions are arranged on the non-skin contact surface side of the top sheet, and each of the back surface convex portions is surrounded by the plurality of back surface concave portions and arranged independently of each other. The absorbent article according to any one of claims 1 to 7, wherein the back surface recesses have spaces connected to each other.   The said back surface recessed part has the top part which consists of a surface sheet, a side wall part, and a bottom part, and there exists a density difference or density gradient of the nonwoven fabric fiber of the surface sheet which increases toward the bottom part from the said top part. Absorbent article as described in 1. The absorbent article according to any one of claims 1 to 9, wherein the absorbent core has a dense structure of fiber density, and there is a portion where the coarse portion of the absorbent core and the space portion overlap each other. .