JP2013111169A - Absorbent article - Google Patents

Abstract

The present invention provides an absorbent article that further enhances absorption performance and further reduces liquid return and station residue.
An absorbent having 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 an absorber 3 interposed between the both sheets. It is an article, and at least the non-skin contact surface side of the top sheet 1 is dotted with back surface convex portions to form an uneven shape, and a liquid-permeable sublayer 6 is provided between the top sheet and the absorber. An absorbent article in which the sublayer 6 and the rear surface convex portion of the top sheet 1 are in contact with each other at the contact portion, and the fiber density of the sublayer at the contact portion is higher than the other portions of the sublayer. .
[Selection] Figure 1

Description

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

  In absorbent articles, such as a disposable diaper, the material and structure of each member were improved and the function and the feeling of wear have been improved. As an improvement of a good wearing feeling, a device for increasing the apparent member thickness while maintaining the distance between the skin contact portion of the diaper and the absorbent body can be mentioned. Thereby, the liquid return to the goods skin contact surface side and the humidity rise in a diaper can be suppressed. Specifically, there are those obtained by laminating sublayers under the surface sheet, those obtained by forming the surface sheet into irregularities with embossing, etc., and those obtained by bonding and fixing the shaped sheet to other nonwoven fabric sheets by pressure bonding etc. . Developments have been made with the intention of such improvements, and in recent years, various types of improved functionality have been proposed in accordance with usage conditions and types of articles.

Patent Document 1 discloses a surface sheet having an uneven structure composed of two layers. The topsheet has a central region in which a large number of convex portions and concave portions are formed and side regions on both sides of the central region. The concave portion of the upper layer sheet in the central region is heated and pressurized by the lower layer sheet and a heat roll, so that the two layers are firmly fixed. Thereby, the said surface sheet has the high liquid return prevention property in which the convex part with a height is stably maintained in the center area | region. And it is supposed that a high leak-proof property can be obtained by the side region excellent in the liquid transfer to the absorber.
Patent Document 2 discloses a two-layer surface sheet having an uneven shape formed by a pin roll. The liquid introduction recess provided on the skin contact surface side of the surface sheet reduces the liquid flow on the skin contact surface side, and is excellent in air permeability and cushioning properties.

JP 2009-118920 A JP 2009-89965 A

By increasing the thickness due to the conventional member lamination, the drawability of the liquid was increased and liquid return was prevented, and a good wearing feeling could be achieved.
The present invention further enhances the absorption performance of conventional absorbent articles, reduces the liquid residue on the skin side that may occur depending on the use state and excretion amount, etc., as well as liquid return and humidity control inside the article. It is an object to provide an absorbent article that can further reduce the burden on the skin of a person.

  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. Further, the non-skin contact surface side of the top sheet has a concavo-convex shape dotted with back surface convex portions, and a liquid-permeable sublayer is disposed between the top sheet and the absorber. And the rear surface convex portion of the top sheet are in contact with each other at the contact portion, and the fiber density of the sublayer in the contact portion is higher than that of the other portions of the sublayer to solve the above problem. It is.

  The absorbent article of the present invention further enhances the absorption performance of conventional absorbent articles, and further reduces the liquid residue on the skin side that may occur depending on the use state, excretion amount, etc., as well as liquid return and suppression of humidity inside the article. And the outstanding effect that the burden on a wearer's skin can be reduced further is produced.

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 partial expanded sectional view which shows typically the arrangement | positioning relationship of a surface sheet and a sublayer. 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 convex part, a sublayer, and an absorber. 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 FIGS. It is explanatory drawing which shows typically the relationship between the back surface convex part and back surface recessed 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 surface sheet. It is explanatory drawing which shows the modification of an absorptive core. It is the drawing substitute photograph which imaged the state after test implementation of the surface sheet in an Example. It is a drawing substitute photograph which imaged the state after test implementation of the surface sheet in a comparative example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
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. A liquid-permeable sublayer 6 is disposed between the top sheet 1 and the absorber 3. The absorbent body 3 is formed by covering an absorbent core with a covering sheet (not shown).
The sublayer 6 is a member that improves the absorption performance by quickly drawing in the liquid from the top sheet 6, spreading the liquid in the planar direction, and efficiently delivering the liquid to the absorber 3. Moreover, the sublayer 6 can increase a member thickness by providing a predetermined distance between the skin contact surface side of the diaper 10 and the absorber 3. Thereby, the liquid return to the surface sheet 1 side is suppressed, and it is effective for suppression of the humidity inside the diaper 10.

  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. The upper side of the absorber 3 is laminated so that the top sheet 1 and the sublayer 6 cover it, and is disposed on the back sheet 2. Each of the top sheet 1, the sublayer 6, 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. Further, a pair of side sheets 4 and 4 are laminated so as to cover both side edges in the longitudinal direction of the surface sheet 1 and further outward in the width direction (X direction). 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, the absorbing portion 3 and the sublayer 6 will be described later, in this embodiment, the top sheet 1 quickly absorbs excreted body fluid and transmits it to the absorber. And the hydrophilic air through nonwoven fabric is used from a viewpoint of the touch. Further, as the back sheet 7, a breathable film having air permeability is used. About the absorber 3, the absorber 3 uses what was comprised from the pulp fiber and the superabsorbent polymer.
The sublayer 6 is made of a sheet mainly composed of a liquid permeable fiber material. The sublayer 6 is preferably one having a fiber density lower than that of the top sheet from the viewpoint of liquid permeability and diffusibility.

  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, and the structure of the surface sheet 1 and the sublayer 6 is demonstrated. 2A is a cross-sectional view taken along the line II-II shown in FIG. 1, and FIG. 2B is a partially enlarged cross-sectional view schematically showing the arrangement relationship between the topsheet and the sublayer 6. FIG. 2-2 is a drawing-substituting photograph in which a cross section of the disposable diaper 10 is imaged. In the drawing-substituting photograph of FIG. 2B, the portion where the back surface convex portion 8 of the top sheet 1 is in contact with the sublayer 6 is shown as a portion surrounded by a broken-line circle.

As shown in FIGS. 2-1 (a) and 2-2, the cross-sectional shape of the diaper 10 has a concavo-convex shape in which the topsheet 1 alternately repeats the back surface protrusions 8 and the back surface recesses 7 with respect to the absorber 3. doing. The top sheet 1 and the sublayer 6 are in contact with each other at the back surface convex portion 8.
In the present invention, the structure of the contact portion between the topsheet 1 and the sublayer 6 (hereinafter, the contact portion is denoted by reference numeral 63) retains the liquid drawing property, liquid diffusibility, and liquid return preventing property of the sublayer. And further reduction of the liquid residue mentioned later is realized. The configurations of the topsheet 1 and the sublayer 6 will be further described with reference to FIG.

As shown in FIG. 2-1 (b), on the non-skin surface side of the top sheet 1, a back surface convex portion protruding from the skin contact surface side (Z ₁ ) to the non-skin contact surface side (Z ₂ ). 8 is formed. A large number of back surface convex portions 8 are periodically arranged adjacent to each other at substantially equal intervals in the surface direction. Then, between the rear surface protrusion 8, and a rear surface recess 7 which is recessed from the non-skin contact surface side (Z ₂₎ to the skin contact surface side (Z _1). This arrangement is an arrangement in which the individual back surface protrusions 8 are scattered in each direction in a plan view. Thereby, the non-skin contact surface side of the topsheet 1 has an uneven shape. In the present embodiment, a surface concave portion 88 is formed on the skin contact surface side of the top sheet 1 corresponding to the back surface convex portion 8, and on the skin contact surface side of the top sheet 1 corresponding to the back surface recess 7. A surface convex portion 78 is formed.

  As described above, the back surface convex portion 8 is a portion protruding toward the absorber 3 on the non-skin contact surface side of the top sheet 1. And the back surface convex part 8 is in contact with the sublayer 6 at the contact part 63 (see FIG. 3). The contact portion 63 fills the gap between the absorber 3 and the top sheet 1, and the suction force from the absorber 3 is easily transmitted to the top sheet 1 through the sublayer 6. Further, the fiber density of the sublayer 6 in the contact portion 63 is higher than the fiber density of the other sublayers (hereinafter, the portion of the sublayer 6 having a high fiber density is referred to as a dense portion 61, and the sublayer having a low fiber density) The portion 6 is referred to as a rough portion 62). Thereby, the capillary force of the dense portion 61 of the sublayer 6 is easier to draw the liquid than the rough portion 62 of the sublayer 6, and in combination with the suction force of the absorbent body 3, it tends to remain on the topsheet 1, particularly the back surface convex portion 8. The liquid can be actively drawn in. Then, the sublayer 6 efficiently delivers the liquid to the absorber 3. As a result, the liquid residue suppression of the surface sheet 1 is further improved, and the humidity suppression between the skin and the surface sheet 1 is further improved.

  In this embodiment, the back surface convex part 8 is made into the rounded top part 8a, and the contact area with the sublayer 6 in the contact part 63 is suppressed suitably. Thereby, liquid return can be suppressed and liquid remaining at the contact portion 63 can be reduced. Moreover, by suppressing the contact area, the liquid absorption performance in the back surface recess 7 described later is not hindered, and is effective in suppressing wetting on the top sheet 1. As long as this effect is exhibited, the back surface convex portion 8 of the top sheet 1 is not limited to the top portion 8a of the present embodiment, and may be a planar shape.

  In the present invention, from the viewpoint of reducing the liquid residue, the constituent fibers of the back surface convex portion 8 that abuts against the abutting portion 63 and the dense portion 61 of the sublayer 6 are not formed into films, and the gaps between the fibers are maintained. This is different from the conventional fiber film formation by heat sealing or the like, and the liquid transfer is not hindered. And the liquid in the surface sheet 1 can be strongly guided to the absorber 3 by utilizing the capillary force of the dense portion 61 of the sublayer 6. Further, since the film is not formed into a film, the contact portion 63 is not made rigid and the touch is improved. And the bulkiness and cushioning property by the surface sheet 1 and the sublayer 6 are not inhibited, and a good wearing feeling is obtained. Further, since the contact portion 63 does not have rigidity due to film formation, even if there is a pressing in the thickness direction from the top sheet 1 side, the force is softened by the contact portion 63 without being transmitted downward. Therefore, liquid return due to pressing is less likely to occur, which is preferable.

Furthermore, it is preferable that the contact portion 63 between the back surface convex portion 8 and the sublayer 6 includes a portion joined by a hot melt adhesive or the like and a portion not joined by the adhesive or the like. Thereby, the balance between the reduction of the remaining liquid and the stabilization of the contact portion 63 can be achieved in a well-balanced manner. In addition, it is preferable that the part joined by an adhesive agent is made the minimum necessary, and it is also preferable to reduce the joint part in the excretion part corresponding | compatible area | region also about the range. By doing so, it is possible to obtain a flexible wearing feeling while preventing the flow of the liquid, which will be described later, to the smooth absorbent body from being hindered by the adhesive. Moreover, the part which the back surface convex part 8 and the dense part 61 in the sublayer 6 contact | connect does not need to be the whole region of the surface sheet 1, and it is preferable to be given to the crotch part C including the excretion part corresponding | compatible area | region at least. The excretion part corresponding region is a part directly receiving excretion of urine or feces and the vicinity thereof.
In this respect, the proportion of the number of contact portions which are joined by an adhesive or the like _{(g 1)} the number of the contact portion unbonded _{(g 2) (g 1 /} g 2) is 1 / 1-1 / 8 is preferable and 1/2 to 1/4 is more preferable. By setting it as the said minimum or more, joining of the surface sheet 1 and the sublayer 6 becomes stable, and the absorption inhibition by an adhesive agent can be prevented by setting it as the said upper limit or less. In the contact portion 63 bonded with a hot melt adhesive or the like, it is preferable that the two fibers are spot-bonded by spray coating or the like without forming an adhesive film. Thereby, even if the fibers of the back surface convex portion 8 and the dense portion 61 of the sublayer 6 are joined together, the gap between the fibers is easily maintained.

  Further, from the viewpoint of stabilization of the contact portion 63, as shown in FIG. 3, the dense portion 61 of the sublayer 6 has a recessed portion that is recessed toward the non-skin contact surface side, and the back surface protruding portion 8 enters the recessed portion. It is preferable that they are in contact with each other. In this state, even if the dense portion 61 and the back surface convex portion 8 are not firmly bonded, the contact state is not easily broken and is easily stabilized. Moreover, since the surface where the back surface convex part 8 touches the dense part 61 spreads moderately in the entering part without expanding the area of the dense part 61, the transfer efficiency to the absorber 3 is improved. On the other hand, it is preferable that the rough portion 62 of the sublayer 6 is bulky and slightly enters the space 72 in the back surface concave portion 7 described later, because the liquid in the space portion 72 is easily guided. The concave portion thickness of the dense portion 61 is preferably 30 to 90%, more preferably 50 to 70% with respect to the thickness of the rough portion 62. By setting it to the above lower limit or more, liquid return at the contact portion and water vapor transpiration into the diaper are suppressed, and by setting the upper limit or less, the contact state between the topsheet 1 and the sublayer 6 is stably maintained. It will be.

On the other hand, the back surface concave portion 7 is a depression on the non-skin contact side surface of the topsheet 1, and is formed by a side wall portion 7b from the top 7a to the bottom portion 7c formed by the topsheet 1 along the depression (FIG. 2). -1 (b)). A rough portion 62 of the sublayer 6 is disposed at the position of the back surface recess 7. A space 72 is formed between the back surface recess 7 and the rough portion 62 of the sublayer 6. The space portion 72 is substantially a void portion even if there is a material in which the fiber material of the topsheet 1 or the sublayer 6 slightly enters. By being a space | gap, the liquid flow resistance of the liquid permeate | transmitted from the surface sheet 1 is low. And since the space part 72 exists in the position comparatively close to the skin side by being in the back surface recessed part 7, it is easy to take in a liquid quickly from the top part 7a or the side wall part 7b, and makes the liquid which the surface sheet 1 received permeate | transmitted actively. easy. In addition, such a space part 72 is preferable also as a buffer part which relieves the influence of the force from the surface sheet 1 side.
Further, since the coarse portion 62 of the sublayer 6 is not as high in fiber as the dense portion 61, the liquid drawability and liquid diffusibility, which are the original functions of the sublayer 6, can be exhibited. The rough portion 62 can quickly deliver the liquid taken into the space portion 72 to the absorber 3 with a large area. From this viewpoint, the fiber density of the sublayer 6 is preferably lower than the fiber density in the vicinity of the back surface recess 7 of the top sheet 1. Moreover, the distance between a wearer's skin and an absorber can be expanded by the structure of the surface sheet 1, the space part 72, and the rough part 62 of the sublayer 6, and thickness can be ensured. Thereby, the liquid return to the skin side can be suppressed suitably.

  As described above, the combination of the space portion 72 and the rough portion 62 of the sublayer 6 improves the absorption rate of the excretory fluid from the topsheet 1 and improves the amount of liquid on the skin contact surface side of the topsheet 1. Diffusion 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 absorbent body 3 which consists of pulp fibers etc., combined with the liquid diffusion effect | action of the sublayer 6, it can deliver a liquid to the absorber 3 rapidly. As described above, the combination of the space portion 72 and the rough portion 62 of the sublayer 6 can quickly recover the space while holding the temporary liquid as a liquid regulating valve, so that not only a large amount of excretion but also repeated excretion Even in this case, it is possible to cope sufficiently. Moreover, if the skin contact side surface of the absorber 3 is substantially flat, this action is more effective and preferable.

From the viewpoint of the absorption speed, the shape of the back surface recess 7 is such that the cross-sectional shape of the back surface recess 7 formed by the side wall portion 7b is a substantially parabolic shape, and the space shape of the back surface recess 7 is a cone such as a cone or a truncated cone with a round top portion 7a The shape is preferably close to a body (cone, truncated cone, pyramid, truncated pyramid, inclined cone, etc.). The gentle inclination of the cone shape allows more liquid to be quickly drawn into the space portion 72 while allowing the liquid to permeate in the thickness direction without impairing the pressure when the liquid is excreted.
Further, the back surface recess 7, 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), the the bottom 7c it is the site of the lowest position of the space (Z ₂ direction). 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 periphery may be planar shape. In this case, the top portion 7a can be determined as the center point of the plane or the highest point in the plane, and the bottom portion 7c can be determined as the center point of the plane or the lowest point in the plane. In this definition, the depth (h ₁ ) of the back surface recess 7 is a height difference of the non-skin contact side surface of the top sheet 1 and is a distance from the top 7a to the bottom 7c (see FIG. 2-1 (b)). ).

The depth of the back recess 7 _{(h 1)} is not uniquely determined varies depending on the size and use of the absorbent article, preferably 0.5 to 4 mm, 1 to 3 mm is more preferable. The depth (h ₁ ) of the back surface recess 7 is obtained by enlarging the cross section of the topsheet 1 passing through the top 7a and the bottom 7c, and the tangent t ₁ (see FIG. 2-1 (b)) of the adjacent bottom 7c and the top 7a. This is done by measuring the distance. The measurement is performed by enlargement using a VH-3000 microscope manufactured by Keyence, and a two-point measurement method after calibration setting. An electron microscope may be used.

As described above, the region of the back surface concave portion 7 (combination of the space portion 72 and the rough portion 62) and the region of the back surface convex portion 8 (the contact portion 63 of the back surface convex portion 8 and the dense portion 61) work together. The liquid absorption performance is improved and the liquid is quickly delivered to the absorber 3 to suppress the liquid return, and at the same time the liquid remaining suppression is improved. Thereby, the contact of the liquid to a wearer's skin is further suppressed and the humidity reduction effect between skin and the skin surface side of the diaper 10 further improves. Such a structure between the members is preferably arranged at least at the crotch part C of the diaper 10. A good dry feeling on the wearer's skin can be realized.
Further, the absorber 3 absorbs and holds the liquid diffused by the sublayer 6 and the space portion 72 on a wide surface, and the area where the liquid reaches the back sheet 2 side is also widened. And it becomes possible to discharge | emit moisture to the exterior from the back surface sheet 2 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 the present invention, from the viewpoint of realizing the above effects, the fiber density (m ₆₁ ) of the dense portion 61 of the sublayer 6 is preferably 15 / mm ^{2 to} 120 / mm ² , and 20 / mm. More preferably, it is ² to 80 / mm ² . Also, the fiber density _{(m 62)} of the rough portion 62 of the sublayer 6 is preferably ten ^/ mm 2 to 100 present / mm ^2, further from 15 present ^/ mm 2 to 60 present / mm ² preferable. Then, the ratio of the fiber density of the dense portion 61 and _{(m 61)} and the fiber density of the coarse portion _{62 (m 62) (m 61} / m 62) is preferably 6 / 5-3 / 1, 7 / 5-2 / 1 is more preferable.
Furthermore, from the same viewpoint, the ratio (n ₆₃ / n ₆ ) of the area (n ₆₃ ) of the dense portion 61 in the area (n ₆ ) on the skin contact surface side of the sublayer 6 is 1/20. 2/5 is preferable, and 1/10 to 1/5 is more preferable. The area (n ₆₃ ) of the planar view region is a region area when the sublayer 6 is planarly viewed from the skin contact surface side without considering a hollow wall surface in the thickness direction.

(Distinction method of dense part 61 and rough part 62)
The dense portion 61 and the rough portion 62 of the sublayer are usually difficult to discriminate boundaries with a clear density. Therefore, the dense portion 61 can be distinguished from the rough portion 62 as a recessed portion or the dense portion 61 as a portion in contact with the back surface convex portion 8.
More specifically, an area in which the cross-section of the sublayer 6 passing through the adjacent dense portions 61 of the sublayer is enlarged, and the curve on the skin side surface of the sublayer 6 is curved and rounded as a concave curve on the non-skin contact surface side. Let's assume the sandwiched part. The cross section of the skin-side surface of the sublayer has an uneven shape in which a curve that is recessed toward the non-skin contact surface and a curve that protrudes toward the skin contact surface are continuously repeated. At the boundary between the dent and the protrusion, the direction of bending changes through a region that is substantially a straight line. A dent portion surrounded by a boundary where the straight line starts to bend and round is defined as a dent.

(Density measurement method)
Using the following scanning electron microscope, magnified observation (adjusted to a magnification capable of measuring 30 to 60 fiber cross sections; 150 to 500 times), and counted the number of cross sections of the fibers cut by the cut surface per fixed area It was. 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.

  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 with the sublayer 6 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. For example, the excretion liquid tends to accumulate in the vicinity of the top portion 88a of the surface concave portion 88 below the side wall portion 78b (= 88b) of the top portion 78a of the surface convex portion 78 (arrow b ₁ ), and is difficult to move in the planar direction. 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.
In this case, as shown in FIG. 5, the excreted liquid that has moved to the front surface recess 88 is drawn into the space 72 from the side wall 88b (= the side wall 7b of the back surface recess 7) (arrow b ₂ ). 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. And the liquid which accumulated much in the surface recessed part 88 cannot fully permeate | transmit at the part, but a liquid residue tends to arise. However, since the non-skin surface side is in contact with the dense portion 61 of the sublayer 6 and the contact portion 63 as the rear surface convex portion 8, the stronger pulling force of the sublayer 6 and the suction force of the absorber 3 are combined. The liquid residue can be effectively eliminated (arrow b ₅ ). Thus, the uneven shape of the front surface convex part 78 and the front surface 88 can make the back surface convex part 8 and the back surface concave part 7 and the sublayer 6 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.

(Modification of the cross-sectional shape of the top sheet)
In the diaper 10, the cross-sectional shape of the top sheet 1 is not limited to the uneven shape of the present embodiment, and any shape is possible as long as the back surface convex portion 8 and the back surface concave portion 7 and the underlying sublayer 6 can be arranged. It can be made into the shape. For example, as shown in FIG. 8, the shape (a) where the skin contact surface side is flat, the shape (b) where the top of the back surface convex portion 8 is flat, and the like can be mentioned. In the case of the shape as shown in FIG. 8B, the bottom portion 7 c of the back surface concave portion 7 is an intersecting portion between the flat surface having the top portion 8 a of the back surface convex portion 8 and the curved surface of the side wall portion 7 b of the back surface concave portion 7.
In these modifications of the topsheet 1, the back surface convex portion 8 is thicker than the back surface concave portion 7. Therefore, the liquid residue tends to occur inside the back surface convex portion. However, even in this case, since the rear surface convex portion 8 is in contact with the dense portion 61 of the sublayer 6, the stronger pull-in force of the sublayer 6 and the suction force of the absorber 3 combine to effectively remove the liquid residue. Can be resolved. Also in this modified example, 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 portion 7a to the bottom portion 7c. By doing so, the liquid can be quickly transmitted from the thin portion of the topsheet 1 to the space portion 72, and the sublayer 6 can powerfully deliver the liquid into the absorber.

(Modification of absorber)
Further, in the diaper 10, the shape of the absorbent core constituting the absorbent body is not limited to the shape of the skin contact side surface of the present embodiment being flat, and the liquid taken in is diffused widely and quickly absorbed and retained. What can be made to adopt is arbitrarily employable. For example, as shown in FIG. 9, 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. An absorbent core 90 (FIG. 9 (a)), 90a (FIG. 9 (b)) composed of 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, the back surface convex part 8, and the contact part 63)
The absorbent article which has the back surface recessed part 7, the back surface convex part 8, and the contact part 63 as shown to FIGS. 2-2 can be obtained in the normal manufacturing process in this kind of goods. 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 it so as to hit a pressure roll. However, since this pressurization and heating are intended to shape the topsheet 1 and form the contact portion 63, it is not so strong as to form a film, such as crimping and fixing between sheets. In this case, the pressurizing condition is preferably 0.2 to 0.8 MPa, more preferably 0.3 to 0.6 MPa. Moreover, when overheating is performed together with pressurization, the heating is preferably from room temperature to 100 ° C, more preferably from 40 to 80 ° C.
Furthermore, when forming a back surface recessed part with the said pressure roll, if the shaping sheet | seat which has an uneven | corrugated shape as shown in FIG. 4 and an uneven | corrugated shape as shown in FIG. The contact portion 63 is more reliably formed, and in this case, it is preferable because a portion having a sub-layer 6 in the contact portion 63 is recessed and a high density 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 sublayer 6, the back sheet 2, the absorber 3 and the side sheet 4, those usually used for absorbent articles can be used.
As the surface sheet 1, for example, a hydrophilic non-woven fabric is preferable, 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.

As the sublayer 6, it is preferable to use a non-woven fabric or a bulky pulp sheet, for example, taking into account the above-described function of diffusing and transmitting the liquid. Specific examples of the nonwoven fabric include air-through nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, and meltblown nonwoven fabric. When these nonwoven fabrics are comprised of hydrophobic fibers, it is preferable to make them hydrophilic using a hydrophilizing agent. The basis weight of the sublayer 5 is preferably ²⁰ to 100 g / m ² , particularly preferably 30 to 80 g / m ² .

  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 body is not limited to that of the above-described embodiment as long as it has a function of absorbing and retaining the liquid therein, and is, for example, a sheet-like thin article. Also good. Further, in the absorbent article of the present invention, the sublayer is not 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 absorber and delivering the liquid to the absorber. It is not limited to a single layer and may be 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 diaper including those having a relationship between a topsheet, a sublayer, and an absorber. If a part of the diaper is broken, it may be a diaper that can be used as a tape, or a urine collection pad, a sanitary napkin, a panty liner, or a 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. While shaping, by fusing each fiber, both the front and back surfaces are in an uneven shape (pitch (w ₁ ) between the top portions 8a-8a of the back surface recesses 8mm 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 hydrophilic air-through nonwoven fabric having a basis weight of 40 g / m ² was used as the sublayer. Non-liquid-permeable back sheet, absorbent core (pulp basis weight 200 g / m ² , superabsorbent polymer basis weight 286 g / m ² ) laminated with hydrophilic paper, laminated in order of sub-layer, top sheet, respectively Were bonded with hot melt. A hot-melt spiral pattern was used for bonding between the sublayer and the top sheet, and the contact portion between the sublayer and the top surface convex portion of the top sheet was mixed with non-bonded ones. This layered sample is sealed at the same pack pressure as the current commercially available diaper “Mary's Sarasara Air Through M Size” manufactured by Kao Corporation, and stored at room temperature for 1 month to create a sublayer uneven structure and fiber dense structure. Formed.
The ratio (m ₆₁ / m ₆₂ ) between the fiber density (m ₆₁ ) of the dense part and the fiber density (m ₆₂ ) of the coarse part of the sublayer was 1.65.

[Comparative Example 1]
The sample of Comparative Example 1 was prepared immediately after the laminated sample of Example 1 was not sealed and stored. The sub-layer of the sample did not have a concavo-convex structure and a fiber density structure like those of Example 1, but remained flat.

[Comparative Example 2]
Of the configuration of the laminated sample of Example 1, the sample of Comparative Example 2 (without sublayer) is obtained by laminating the absorber and the topsheet directly without laminating the sublayer between the absorber and the topsheet, and not sealingly storing it. It was.
[Comparative Example 3]
A commercially available disposable diaper (trade name “Merry's Sarah Air Through M size”) manufactured by Kao Corporation was used as a sample of Comparative Example 3. The sample is a diaper using a two-layer surface sheet formed by heat sealing and having a concave and convex skin surface side and a flat non-skin surface side, and a sub-layer.

[Performance evaluation]
About the sample (disposable diaper) of an Example and a comparative example, the liquid return amount and absorption time in the division | segmentation injection under pressure, and the liquid residual amount to a surface sheet were measured. As the measurement test, the following two types of tests (1) and (2) were performed.
(Test 1)
First, for each sample of Example 1 and Comparative Examples 1 to 3, the central portion of the absorbent body in the width direction at a length of 155 mm from the ventral absorber end of the sample developed in a plane to the back end is injected into the liquid. Points. An acrylic plate with a cylindrical injection portion is placed on the sample so that the liquid injection point of the sample is at the center of the injection portion, and a weight is further placed on the acrylic plate, and 2.0 kPa (20 gf / cm ² ) A load was applied. The injection part provided in the acrylic plate has a cylindrical shape (height 53 mm) with an inner diameter of 36 mm. The acrylic plate has a cylindrical part of the cylindrical injection part at a third portion in the longitudinal direction and the central axis in the width direction. A through hole having an inner diameter of 36 mm is formed so that the central axes coincide with each other and communicates between the inside of the cylindrical injection portion and the surface sheet facing surface of the acrylic plate.
While maintaining the liquid height of 10 mm from the injection part, 40 g of artificial urine was injected. The time from the start of injection until the artificial urine disappeared from the top sheet was taken as the absorption time. 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 mass, water 96.88% by mass and polyoxyethylene lauryl ether EO added mole number 41 (about 0.07%), with surface tension adjusted to 53 ± 1 dyne / cm (23 ° C.) It is.
The artificial urine was injected four times at 10-minute intervals and allowed to stand for 10 minutes. Then, the weight and the acrylic plate were removed, 16 filter papers (ADVANTEC 5C 10 mm × 10 mm) were placed on the sample, and the weight was further placed thereon. A load of 3.4 kPa (35 gf / cm @ 2) was applied. After leaving in that state for 2 minutes, the mass of artificial urine absorbed by the filter paper was measured, and the amount was taken as the liquid return amount.

(Test 2)
About each sample of Example 1 and Comparative Examples 1 to 3, the central part of the absorbent body in the width direction at a length of 155 mm in the longitudinal direction from the end part of the ventral side absorbent body of the sample developed in a plane is defined as a liquid injection point. did. A notch was cut in advance in the surface sheet (10 mm × 20 mm) around the injection point, and 80 g of artificial urine was injected at a rate of 5 g / sec using a pump. After standing for 10 minutes, the surface sheet was gently peeled off and the mass was measured. Artificial urine absorbed in the top sheet was sucked up with a Kim towel or the like, and the top sheet was left to dry overnight, and a value obtained by subtracting the mass after drying from the above mass was defined as the remaining liquid amount.

  The evaluation results are shown in Table 1 below. Samples used in the liquid residue test are shown in FIGS. FIG. 10 shows the state after the test of the top sheet of the test body of Example 1, and FIG. 11 shows the state after the test of the top sheet of the test body of Comparative Example 1. 10 and 11, (a) shows the skin contact surface side of the top sheet, (b) shows the non-skin contact surface side, and (c) partially enlarges (b). It is the drawing substitute photograph shown. In any drawing-substituting photograph, the black portion indicates the liquid residue.

(Table 1)
---------------------------------------
Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3
---------------------------------------
Liquid return amount in pressure division injection 0.14 g 0.33 g 0.84 g 1.09 g
---------------------------------------
Absorption time (at the time of the fourth injection) 38 seconds 65 seconds 92 seconds 33 seconds (injection amount 160 g, standing time 10 minutes)
---------------------------------------
Liquid remaining amount of surface sheet 0.11 g 0.16 g 0.10 g 0.27 g
(Injection amount 80 g, standing time 10 minutes)
---------------------------------------

As is apparent from the results shown in Table 1, in the diaper (Comparative Example 3) of the two-layer surface sheet shaped by heat sealing, the space is maintained without the unevenness on the skin side of the surface sheet entering the sub-layer even under pressure. Therefore, although the absorption rate was fast, the amount of liquid retained and the amount of liquid returned retained inside the surface material was less in the disposable diapers of Example 1 and Comparative Examples 1 and 2. This is because, in the disposable diapers of Example 1 and Comparative Examples 1 and 2, since the topsheet is an uneven shape and has one layer, the thickness is reduced particularly under pressure, and the back surface convex portion of the topsheet absorbs the lower layer. By entering the body and sublayers.
Furthermore, when comparing the disposable diaper of Example 1 and Comparative Example 1 with a sub-layer and Comparative Example 2 without a sub-layer, the sub-layer plays a large role in suppressing the amount of liquid return, and in particular, there is a sub-layer in pressurized divided injection As a result, it was found that the liquid return amount was greatly reduced. Moreover, it became clear that absorption time was quicker than the comparative example 2 without a sublayer from the role which becomes bulky by having a sublayer, hold | maintains a liquid temporarily, and spread | diffuses in a plane direction.
In addition, the disposable diaper of Example 1 further reduced the amount of liquid return compared with Comparative Example 1, and the absorption time was shortened to an extent comparable to that of Comparative Example 3 to improve the original function of the sublayer. In addition, the liquid residue was suppressed as compared with Comparative Example 1. This can also be seen from the manner in which the remaining liquid black in FIG. 10 (Example 1) is clearly thinner than that in FIG. 11 (Comparative Example 1). The result of the liquid remaining suppression in this Example 1 is that the sub-layer makes it difficult for the absorbent body to absorb water due to the surface sheet being far from the absorbent body, and the liquid remaining amount on the surface sheet tends to increase. This shows that (Comparative Example 1) was overcome and the liquid residue could be reduced to a level equivalent to that of Comparative Example 2 with no sublayer. That is, it can be seen that the disposable diaper using the uneven sublayer of Example 1 is excellent in achieving both the merit with the sublayer and the merit without the sublayer.

DESCRIPTION OF SYMBOLS 1 Top sheet 2 Back sheet 3 Absorber 4 Side sheet 6 Sublayer 61 Dense part 62 Rough part 7 Back surface recessed part 8 Back surface convex part

Claims (7)

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,
On the non-skin contact surface side of the top sheet, a back surface convex portion is dotted to form an uneven shape, and a liquid-permeable sublayer is disposed between the top sheet and the absorber, and the sublayer and the The back surface convex part of the top sheet is in contact with the contact part,
An absorbent article in which the fiber density of the sublayer in the contact portion is higher than that of other portions of the sublayer.   The peripheral portion of the back surface convex portion on the non-skin contact surface side of the top sheet forms a back surface recess recessed from the non-skin contact surface side to the skin contact surface side, and between the back surface recess and the sublayer The absorbent article according to claim 1, wherein a space portion is formed, and a fiber density of the sublayer located at the position of the space portion is lower than a fiber density of the sublayer in contact with the back surface convex portion.   The absorbent article according to claim 1 or 2, which has a fiber structure in which a gap between fibers of both members is maintained at a contact portion between the back surface convex portion of the top sheet and the sublayer.   The absorptive article given in any 1 paragraph of Claims 1-3 in which a thing stuck and a non-adhesion thing are mixed in a contact part of a back surface convex part of said surface sheet, and said sublayer. .   In the contact portion between the back surface convex portion of the top sheet and the sub layer, the sub layer has a concave portion recessed toward the non-skin contact surface side, and the back surface convex portion of the top sheet enters and contacts the concave portion of the sub layer. The absorbent article according to any one of claims 1 to 4.   The absorbent article according to any one of claims 1 to 5, wherein a ratio of a region area of a contact portion with a back surface convex portion to a sheet area of the sublayer is 1/20 to 2/5. The absorbent article according to any one of claims 1 to 6, wherein the fiber density of the sublayer in the contact portion with the back surface convex portion of the top sheet is 15 pieces / mm ^{2 to} 120 pieces / mm ² .